WO2010020385A2

WO2010020385A2 - Apparatus and method for monitoring individual photovoltaic modules of a photovoltaic system

Info

Publication number: WO2010020385A2
Application number: PCT/EP2009/005945
Authority: WO
Inventors: Jürgen REIMANN
Original assignee: Eprotech Reimann E.K.
Priority date: 2008-08-22
Filing date: 2009-08-17
Publication date: 2010-02-25
Also published as: DE202008012345U1; WO2010020385A3; DE102008039205A1

Abstract

The invention relates to an apparatus for monitoring individual photovoltaic modules of a photovoltaic system. A device for determining and/or evaluating electrical parameters of a photovoltaic module, in particular the voltage U and/or the current I, is connected to each of several photovoltaic modules, and at least one device for determining and/or evaluating electrical parameters of a photovoltaic module is coupled to a center in order to transmit data to said center in a wireless way and in intervals rather than in a permanent, i.e. uninterrupted, manner. The data is transmitted without modifying the frequency spectrum of an output variable of the respective photovoltaic module and by means of electromagnetic waves. Finally, the data to be transmitted is modulated onto an oscillator signal and is ultimately emitted via an antenna.

Description

Device and method for monitoring individual photovoltaic modules of a photovoltaic system

The invention is directed to a device for monitoring individual photovoltaic modules of a photovoltaic system, wherein in and / or at a plurality of photovoltaic modules depending on a device for determining and / or evaluation of electrical parameters of a photovoltaic module, in particular of voltage U and / or current I _{1 is} connected Furthermore, at least one device for determining and / or evaluating electrical parameters of a photovoltaic module for the purpose of transmitting information is coupled to a control center, and wherein the information is transmitted by a device for determining and / or evaluating electrical parameters of a photovoltaic module by wireless means and not permanently, ie without interruption, but at intervals.

A photovoltaic system generally includes a plurality of photovoltaic modules that capture the light energy of the sun and convert it into electrical energy. Each solar cell delivers an electrical voltage of about 0.5 volts due to the photovoltaic effect. In order to generate a rated voltage of, for example, 12 volts or 24 volts or more, several solar cells are usually connected in series and integrated into a photovoltaic module.

In a photovoltaic system, several photovoltaic modules - up to many thousands of modules - can be interconnected in order to multiply the energy yield. Here, in principle, series connections of photovoltaic modules are possible, with their voltages adding, but all modules are traversed by the same current, as well as parallel circuits, all photovoltaic modules have the same voltage, but the currents add up; In addition, combinations of these two types of circuit are conceivable. Regardless of the type of circuit, the energy yield or the efficiency of each individual photovoltaic module can fluctuate to a considerable extent. The maximum achievable efficiency is about 12% for monocrystalline silicon-based solar modules and about 10% for polycrystalline solar modules. However, the maximum efficiency results only at an optimum module temperature of about 25 ⁰ C. With increasing temperature, the efficiency drops significantly.

Optimum efficiency, however, only leads to a maximum energy yield with maximum solar radiation power. However, such a maximum solar radiation power almost inevitably entails a not inconsiderable heating of the modules, which in turn lowers the efficiency. It can be seen from this that, for example, optimal cooling of the modules can have a not insignificant influence on the energy yield.

Conversely, of course, shading of individual modules also results in a reduction in the energy yield of the photovoltaic modules affected. In this case, cooling does not improve the energy yield.

Furthermore, individual modules may be damaged, for example by hail, so that not all their solar cells work; even then a reduced energy yield is the result, but this can be remedied by replacing the relevant module.

Finally, the connection of individual solar modules can be damaged if, for example, - it was torn off by storm, but also by vandalism - cable. This goes up to the theft of solar modules, which unfortunately - due to the high value of a solar panel - occurs more frequently. From this it can be seen that the energy yield of a photovoltaic module is influenced by a whole series of factors, some of which are controllable. However, it is important - especially in large solar fields with a few hundred or even a few thousand modules - to recognize which modules are not working properly.

By transmitting company-specific data to a central office, it is possible to assess whether and, if so, which photovoltaic modules have experienced an irregularity or even a malfunction.

However, the cost of such monitoring should be kept as small as possible.

In addition, when connecting the decentralized sensor devices, it should be noted that photovoltaic modules can be connected in parallel and / or in parallel as required or as required by the connected consumer / supply device

Series can be switched and operated. Especially with a

Series connection, the individual modules are clearly different

Voltage potentials, so that potential problems can occur in a coupling via a line. To exclude this, a wireless data transmission is preferred according to the invention. On the other hand, however, this entails a certain power consumption, so that - i.a. to save energy - a permanent data transmission is omitted, but the same takes place only at intervals. Nevertheless, the required transmission energy should be further reduced to the efficiency of

Do not reduce modules by the monitoring device itself.

From the disadvantages of the prior art described results in the

Invention initiating problem, a generic device for monitoring individual photovoltaic modules of a photovoltaic system in such a way that defective or not properly connected Modules can be detected with the least possible effort; if possible, the required energy consumption should be minimal.

The solution to this problem succeeds in a generic device for monitoring individual photovoltaic modules of a photovoltaic system in that the information transfer without changing the

Frequency spectrum of an output of the relevant

Photovoltaic module takes place and by means of electromagnetic waves, wherein an oscillator signal, the information to be transmitted are modulated and finally emitted via an antenna.

By means of the transmission technology according to the invention, the structure of the relevant photovoltaic module as well as its mode of operation is not influenced; In particular, all individual solar cells of a module can be connected to one another unchanged and to the module connections galvanically or via semiconductors (diodes), as is also the case with conventional solar panels.

The coupling to a central unit should be done without additional cables to be laid, namely by wireless means, so that the wiring effort in the construction of a solar panel remains minimal. In addition, a wiring in a theft can be easily cut with a pair of pliers, a wireless connection, however, not, at least not abruptly. In any case, a decentralized monitoring device cut off from the installation would detect the current flow "0" and could forward it to the control center, which would then be informed without delay.If at the same time the relevant voltage value is not equal to "0", this indicates, for example, a Connection problem, in extreme cases, even to the theft of the relevant module.

By not using the power cables for information transmission, the frequency spectrum is influential, clocked Power semiconductors superfluous, whereby the effort is further reduced; This also switching losses due to the timing are avoided. Since the information transmission according to the invention takes place on a separate channel and thus manages completely without influencing the tapped on a photovoltaic module current and / or Spanπungswerts, in particular - mechanical and / or electronic - switching means for chopping the voltage is not required - the modules can be used both in Row as well as be connected in parallel. Neither the voltage nor the current must be autodulated any information. This also makes expensive even more expensive power semiconductors. In addition, even in the case of a line break - whereby no transmission via the / the power cable would be more possible - at least the information is transmitted, if the module itself generates at least voltage. As a result, the error can possibly be limited to the connecting lines, the assumption of theft attempt is obvious.

In contrast to ultrasound, for example, electromagnetic waves do not disturb the surrounding nature and can therefore also be used in remote locations.

By modulating the information to be transmitted to an oscillator signal, the radio wave spectrum required for data transmission can be narrowed so that interference or interference with other radio signals is not to be feared. The low energy requirement required by such a transmission device can be covered by the respective photovoltaic module, the type of operation of the transmission device, in particular the interval operation, further reducing the energy requirement.

On the other hand, however, each decentralized evaluation device has its own (radio) transmitting device, so that possibly also a communication between individual modules - without participation of a central office - is possible. This technology has also the advantage of a further reduced transmission power, since a single module does not have to send directly to a central receiving station, but only up to a relay, a repeater or a coupled to an adjacent photovoltaic module evaluation. On the other hand, it is - in contrast to the use of purely passive transponders, which do not have their own transmitting device - thus possible to bridge larger distances of several meters, while transponders are limited to much shorter distances of a few centimeters and therefore for a coupling to an adjacent module or to remote (central) receiving antennas are hardly suitable.

Compared to a separate information cable has the advantage of easier connection. Due to the lack of an additional coupling galvanic, no potential problem can result from different power-related couplings of the individual modules - connected in parallel or in series. Each detection, evaluation and communication device can be directly connected to a terminal of the relevant module in terms of potential. Since there is no potential coupling between the modules in addition to the power cables, a decoupling is not required.

The coupling to a center is preferably carried out by means of waves, which can be transmitted in different ways, in particular by infrared light, and also by means of electromagnetic waves (radio). The latter transmission method is the least susceptible to interference from natural environmental influences and will therefore be preferable in many cases.

The invention is further distinguished by a device for measuring or detecting the temperature of a photovoltaic module.

Further advantages are provided by a device for measuring or detecting the light radiation intensity impinging on a photovoltaic module, and / or one Device for measuring or detecting the ambient brightness of a photovoltaic module.

Furthermore, it is also possible to provide a device for measuring or detecting the movement of a photovoltaic module, for example a rangefinder which measures the distance to the ground or to another, adjacent body, either one-dimensionally or multi-dimensionally.

The invention is supplemented by one or more means for converting the measurement results into digital values and providing them in serial or parallel form.

The transmission of information about the parameters of a photovoltaic module is independent of a request from a center, but spontaneously or triggered by adjacent, decentralized monitoring devices, in particular by signals received from there.

In a particularly preferred embodiment, the transmission of information takes place unidirectionally from a photovoltaic module to a central office. This has the advantage that a receiving device in the decentralized detection devices in the range of a photovoltaic module are dispensable.

Preferably, the transmission of information from different photovoltaic modules is not simultaneous.

It has proved to be favorable that the transmission of information from the photovoltaic modules to a central unit takes place asynchronously.

The invention is further distinguished by an oscillator for generating the oscillating signal. An alternative embodiment, however, includes a block for cyclically outputting a sequence of signal values of a periodic, preferably sinusoidal, waveform to a downstream digital-to-analogue converter for generating the oscillating signal.

To reduce the circuitry complexity is further provided that the frequency of the oscillating signal in some, several or all photovoltaic modules in the same radio band, especially in the same channel.

It has been proven to choose the frequency of the oscillating signal at 100 MHz or above, preferably at 200 MHz or above, especially at 400 MHz or above. On the other hand, the frequency of the oscillating signal should be 1500 MHz or less, preferably 1200 MHz or less, more preferably 1000 MHz or less.

For transmitting information by means of the oscillating signal is particularly suitable a module for modulating the oscillating signal according to a pulse modulation method, for example. A pulse amplitude modulation (PAM), or a pulse-code modulation (PCM), or a pulse frequency modulation (PFM) ₁ in particular by means of frequency shift keying ( Frequency Shift Keying (FSK), or a pulse phase modulation (PPM) method, or a

Pulse Width Modulation (PWM), or Pulse Pause Modulation (PPM).

The arrangement may be such that the device modulates the oscillating signal with an information signal of 2 or more data words per measurement sequence, preferably with an information signal of 3 or more data words per measurement sequence, in particular with an information signal of 4 or more data words per measurement sequence. It can - depending on Accuracy requirements - have a data word of 8 bits, for example, or a length of 16 bits, or even 32 or 64 bits.

A module for modulating the oscillating signal with a data or baud rate of 2000 baud or more, preferably 4000 baud or more, in particular 8000 baud or more, has proven particularly useful. The higher the data rate, the shorter the duration of the signal to be transmitted, and therefore the less susceptible to interference.

Further advantages are provided by at least one device for reducing or switching off the transmission power of the oscillating signal in the phases between the transmission of data.

For this purpose, for example, is a device for reducing or switching off the transmission power of the oscillating signal for a "short" transmission interval of 0.2 seconds or more, preferably for an interval of 0.5 seconds or more, especially for an interval of 1 second or more.

On the other hand, it is also possible to provide a device for reducing or switching off the transmission power of the oscillating signal for a "long" transmission interval of 2 seconds or more, preferably for an interval of 5 seconds or more, in particular for an interval of 10 seconds or more.

It is within the scope of the invention that the devices for a "short" transmission interval and for a "long" transmission interval are activated alternately following each data transmission, ie after one data transmission follows the next after a short transmission pause, then the third follows after a long pause, then the next again after a short pause, etc. The short or long pause can be fixed, or variable, for example. Affected by a device-specific, stored code. This can be achieved that the Send measuring devices of different photovoltaic modules all in pairs at different time intervals. As a result, a repeated temporal superimposition of transmission signals of different photovoltaic modules can be excluded. By - as the invention further provides - the transmission pauses, in particular the long transmission pause, a multiple of the duration of a transmission signal corresponds, for example, 200 times or more, preferably 500 times or more, especially 1000 times or more the probability of a random temporal superposition very low. Since, in addition, the stored, device-specific code of a monitoring module is transmitted with each data transmission, an exact assignment at the receiver or in the control center is possible. Should an overlay nevertheless occur, the resulting interference will lead to the fact that the received signal can not be assigned to a photovoltaic module, and is discarded. The two-time data transmission in the short transmission interval, a second, redundant transmission signal is provided in such a random overlay, which can replace the lost.

By the information transmission without changing the frequency response or frequency spectrum of an output of the photovoltaic module concerned takes place, for example. Its terminal impedance or its Eiπspeisespannung or feed, the energy input from the information transfer remains largely unaffected. In addition, so that band passes, especially frequency-dependent short circuits od. Like. Be avoided. In the context of the invention is not intended to couple the individual photovoltaic modules via inverter to a common rail; the performance shading is only parallel and / or in series; in the latter case, therefore, all photovoltaic modules could even be at the same potential. Such galvanic coupling has the advantage of least losses. The invention further provides that the transmission of information about the parameters of a photovoltaic module is independent of a request of the center, but spontaneously or triggered by adjacent, decentralized monitoring devices, in particular by signals received therefrom. A spontaneous transmission will take place when the module current sensed by a decentralized monitoring device abruptly goes back to "0", so that the suspicion of theft is obvious and rapid countermeasures are to be initiated, for example the activation of a siren, or the notification of persons, or For example, if several modules fail in short intervals - possibly even the police.

It has proved favorable that the transmission of information from different photovoltaic modules is not simultaneous; This makes it possible, if necessary to make do with a single transmission channel, so that all transmission devices can be identical, which minimizes the production cost.

It is possible to integrate at least one device for determining and / or evaluating electrical parameters of a photovoltaic module with a photovoltaic module. In this case, possibly in the manufacture of the solar panel or a solar cell of the same a corresponding (semiconductor) circuit can be incorporated simultaneously.

On the other hand, it is also possible that at least one device for determining and / or evaluating electrical parameters of a

Photovoltaic module is coupled to the electrical connections of a photovoltaic module or coupled. At the connections can be electricity and

Measure voltage of the relevant photovoltaic module; at the same time

Energy for supplying the monitoring circuit available; Finally, the connections of photovoltaic modules are usually standardized, so that a universal coupling is possible here. In this context, an arrangement proves to be particularly advantageous, wherein at least one device for determining and / or evaluating electrical parameters of a photovoltaic module is connected between the electrical connections of a photovoltaic module and from there further electrical cables. Thus, the module voltage between two terminals of the monitoring circuit, the module current even flows through the monitoring circuit and can therefore also be tapped.

In continuation of this inventive idea, it is provided that at least one device for determining and / or evaluating electrical

Parameter of a photovoltaic module has at least three electrical connections, preferably at least four. One between a module and its

Connecting lines connected monitoring circuit must have at least one two-pole input for voltage measurement and at least one output to flow out of the stream, so a total of at least three

Connecting contacts. The connection of an external cable is usually simplified, if - as well as for connection to the photovoltaic module itself - two connection contacts are available. The further connection of several photovoltaic module assemblies - each a photovoltaic module together with the monitoring device connected thereto - can then after

As desired, parallel and / or serial, as desired in each individual case.

The inventive construction can be further optimized by at least one device for determining and / or evaluation of electrical

Parameter of a photovoltaic module to their own power supply has a rechargeable energy storage, for example. A battery, capacitor od. Like. Such energy storage can during the day, i. at

Solar irradiation and generation of electricity to be charged by the relevant photovoltaic module and is then at dusk and

Darkness as an energy source available, so even at night - when the

Risk of theft is greatest - monitoring can be done if necessary, at longer intervals to save energy. However, in the event the module voltage is anyway zero at night, it may be sufficient in this case to check only the presence of the module by means of a short impedance measurement or even to signal only the presence of the monitoring device itself and its integrity.

It is within the scope of the invention that at least one device for determining and / or evaluating electrical parameters of a photovoltaic module has at least one antenna for transmitting and / or receiving radio signals. Such an antenna enables the device in question to participate in a conversation with the control center or with other monitoring devices wirelessly.

It has proved to be advantageous that at least one device for determining and / or evaluating electrical parameters of a photovoltaic module has at least one device for mapping the module voltage and / or the module current to Qe), an approximately proportional current and / or voltage value. A voltage divider connected between the module terminals or between the output terminals of the monitoring device is suitable for generating a reduced voltage, a voltage value proportional to the module current can be generated by means of a shunt looped into the power line.

The invention can be further developed in that at least one device for determining and / or evaluating electrical parameters of a photovoltaic module has at least one device for multiplying an approximately proportional to the module voltage current and / or voltage value with an approximately proportional to the module current current and / or voltage value, in order to determine the power produced by the module. The power generated is a very meaningful parameter of a module and can be easily derived from electricity and electricity Determine voltage readings, either by an analog multiplier circuit or by a digital multiplication.

Furthermore, at least one device for determining and / or evaluating electrical parameters of a photovoltaic module can have at least one device for mathematically integrating a current and / or voltage value which is approximately proportional to the module voltage and / or to the module current and / or to the module power predetermined time intervals. The instantaneous value of the power provides by integration the generated energy - an extremely meaningful value via a photovoltaic module that masks out smaller variations in power and instead represents the electrical work substantially generated within an interval, preferably within constant intervals, especially between successive transfers of information ,

The invention further provides that at least one device for ascertaining and / or evaluating electrical parameters of a photovoltaic module has at least one device for sampling and / or (temporarily) holding constant one to the module voltage and / or to the module current and / or to the module output proportional and / or (intermittently) integrated current and / or voltage value, preferably at regular time intervals. Preferably, an integration interval is standardized and slightly shorter than the distance between two information transmissions. At the end of the integration process - or, if an integration is omitted, at a time between two information transmissions - a measurement signal is sampled and / or held constant for further processing.

Downstream of such a sample and / or hold circuit, a device for determining and / or evaluating electrical parameters of a photovoltaic module has at least one device for converting one to the module voltage and / or to the module current and / or to the module power approximately proportional and / or (eg., To the generated energy) integrated, preferably sampled and / or (temporarily) held constant current and / or voltage value in (each) a digital value. Such digital values are far better suited for precise information transmission to a control center than analog values which could be corrupted during transmission.

Furthermore, at least one device for determining and / or evaluating electrical parameters of a photovoltaic module should have at least one device for storing Oe) one approximately proportional to the module voltage and / or to the module current and / or to the module output and / or (for example to the generated Energy) on integrated, digitized value. As a result, the digitized measured value (s) is / are stored at least until the time of data transmission; the data transmission itself can, for example, be triggered in a time-controlled manner, that is to say take place spontaneously or, for example, be triggered by receiving a signal from a (neighboring) monitoring device.

In the context of a preferred embodiment of the invention, at least one device for determining and / or evaluating electrical parameters of a photovoltaic module has at least one device for storing a module- and / or device-specific code, for example a module- and / or device-specific number. As a result, the monitoring device concerned can provide the data or other information transmitted to a central station or to an adjacent monitoring module with a type of sender's mark, so that each recipient knows exactly from where a message originated.

According to the invention, at least one device for determining and / or evaluating electrical parameters of a photovoltaic module has at least one oscillator for generating a vibration in a predetermined one Frequency band. Preferably, the oscillator need not be adjustable, but can remain fixed when the information transfer is transmitted by means of amplitude or pulse modulation; if the data transmission should be done by means of frequency modulation, an adjustment would be required.

At least one gain element may be provided to generate the output of the oscillator at the required transmit power and / or to boost to the required transmit power. In the former case, the output signal of the amplifying element - preferably a transistor, for example. A field effect or bipolar transistor - fed back to its input (partially). In the latter case, an amplifier is connected downstream of the oscillator, wherein the amplification element could, for example, be operated in emitter or source circuit.

If at least one device for determining and / or evaluating electrical parameters of a photovoltaic module has at least one device for modulating a transmission signal with a module or device pacific code, for example a module- or device-specific number, and / or for its modulation with (one) each to the module voltage and / or to the module current and / or to the module power approximately proportional and / or (intervalwise) integrated, digitized value, the oscillator signal is used as a carrier signal to which a receiving station can be set, so that a transmission channel is opened ,

On the other hand, at least one device for determining and / or evaluating electrical parameters of a photovoltaic module may have at least one device for demodulating a received signal in order to obtain its transmitted information. In this way, a receiving station can in particular determine the sender of a received message and, for example, make preprogrammed actions, for example one's own Information - possibly together with the last received data - submit or forward.

For precisely this purpose, a device may also be provided in a decentralized monitoring component for temporary storage of the

Information content of a received signal, preferably in order to aufzumodulieren the transmitted information in a subsequent transmission step the carrier signal of the oscillator for the purpose of radiation again. Thus, the information of several monitoring components can be successively joined together to create a collective telegram, which after

Passing through all the monitoring components finally contains the information about all photovoltaic modules.

Finally, such - complete - collective telegram - but possibly also a message of a single monitoring component - preferably reaches a central receiving station for receiving one or more information of the device (s), which ultimately has the responsibility to evaluate the contained electrical parameters of individual photovoltaic modules.

Ideally, the central receiving station receives within a read-out interval, therefore, only a single collective telegram with the information of all photovoltaic modules. It may, however, be provided that, in the case of very extensive installations, a plurality of decentralized antennas and / or repeaters are provided in order to couple several partial areas of a solar field separately, for example via a separate, remote receiving antenna or via a repeater on site. As a result, on the one hand, possibly the transmission power required for operation can be further reduced; On the other hand, if communication fails, only part of the system would be affected. Since the data transmission path is not predetermined by hardware - there are no information transmission lines - it can also be provided that photovoltaic modules, which have lost their preferred receiving device - for example, by a theft or other defect - connect radio-technically another, intact transmission or data transmission branch or path - ie, for example, via another, also close solar module, so as to allow a redundant data transmission.

The central receiving station should have means for evaluating the received information, for example a microprocessor, and / or an arithmetic processor for determining mean values and deviations, scatters, etc.

Furthermore, the central receiving station can have means for the delivery and / or forwarding of signals. It may, for example, be connected to a telephone network in order to notify certain persons or organizations of predefined situations. It may also be coupled to one or more sirens; the switching on of light masts can also be provided in order to deter possible thieves, etc. Furthermore, the central receiving station can be coupled to a mass memory in order to document and / or to archive all system data.

A method according to the invention for monitoring individual photovoltaic modules of a photovoltaic system is characterized in that one or more electrical parameters, in particular voltage and / or current, are determined and / or evaluated in and / or at several photovoltaic modules, as well as these and / or information obtained therefrom a central office will be transmitted.

When transmitting any information to the control center, a module-specific code is added, so that the relevant information in the control center can be uniquely assigned to a specific module.

The received information can be compared with each other in the central office and / or with a mean value formed from the values of several or all photovoltaic modules, for example by significant deviations of individual ones Determine modules. The significantly different module parameters can be further evaluated, for example, to be able to draw conclusions about the cause, for example. To differentiate between a theft on the one hand and a hail or storm damage on the other hand and other impairments of the module performance, eg. Excessive heating of the same or shading to be able to.

In addition, when significant deviations are detected on one or more modules, a message about the event is generated.

Such reports of significant discrepancies may be collected and / or stored for documentation purposes and / or they may be sent to one or more given recipients.

Significant deviations can be used to trigger safety measures, such as turning on a siren.

A further advantage of the invention is that information is also transmitted between decentralized devices for monitoring parameters (each) of a photovoltaic module.

The invention can be further developed such that the transmission of information from / to a plurality of decentralized devices for monitoring parameters (each) of a photovoltaic module takes place on a common carrier medium, in particular on a common transmission channel.

Finally, it is the teaching of the invention that the transmission of information from / to several decentralized devices for monitoring parameters (each) of a photovoltaic module does not take place on the energy-carrying lines of the photovoltaic system. Further features, details, advantages and effects on the basis of the invention will become apparent from the following description of a preferred embodiment of the invention and from the drawing. Hereby shows:

Figure 1 shows the basic arrangement of a photovoltaic system for feeding the generated electricity into an existing power grid.

FIG. 2 is a schematic block diagram of the power components of the system of FIG. 1; FIG.

FIG. 3 shows the monitoring components for the system with the block diagram according to FIG. 2; FIG. such as

4 shows a circuit diagram section with the coupling of some monitoring components from FIG. 3 to a respective photovoltaic module according to FIG. 2.

In the photovoltaic system 1 of Fig. 1 is a so-called. Solar field, so a large plant with many hundreds or even thousands of photovoltaic modules 2, of which only a few are shown by way of example.

From Fig. 1 is further seen that the photovoltaic modules 2 are all connected together and the power lines 3, 4 are brought together in a control center 5, where the recovered solar power is converted into AC voltage and then fed into an existing power grid 6.

Finally, FIG. 1 also shows the case, which is not uncommon in large solar fields, that some photovoltaic modules 2 are exposed to direct solar radiation (left in FIG. 1), while other photovoltaic modules 2 are simultaneously Shadowed, for example, by a cloud (in Fig. 1 right). In this situation, the energy yield of the shaded modules 2 (right) would decrease rapidly, and in particular also the local module current. So that the sun-shined modules 2 (left) are not impaired, their (higher) module current can be conducted past the shaded modules 2 by bypass diodes 7, ie even with a series connection of photovoltaic modules 2 there is the possibility of different currents through the individual modules (The voltage can always be different in series connection anyway). Similar solutions are also available for the parallel connection of photovoltaic modules 2.

FIG. 2 shows by way of example two line strands 8 connected in parallel, each with four photovoltaic modules 2 connected in series, in order to explain that it is completely unimportant for the invention whether individual photovoltaic modules 2 are connected in parallel or in series with one another.

In the example shown, the line strands 8 are connected in the control center 5 together on a single generator connection box 9; this is followed by a main switch 10th

Beyond this main switch 10, an inverter 11 is connected, which converts the DC voltage of the strings 8 connected in parallel in the generator connection box 9 into an alternating voltage synchronous with the mains voltage 6, which is finally fed into the network 6.

To monitor the individual photovoltaic modules 2 is a monitoring system 12, which is shown in Fig. 3.

This consists of a plurality of decentralized monitoring devices 13 and at least one central monitoring station 14. While each decentralized monitoring device 13 is arranged in the immediate vicinity of each photovoltaic module 2 and is associated with this monitoring technology, the central monitoring station 14 is preferably located in or at the control center 5.

The coupling of a decentralized monitoring device 13 to a photovoltaic module 2 can be seen in FIG. 4: Similar to a battery, each photovoltaic module 2 has only two connections, namely a positive pole 15 or anode and a negative pole 16 or cathode. These two poles 15, 16 are usually provided with (each) a short cable 17, which is preferably terminated with (each) a standardized plug 18, a so-called MC plug, or socket, in order to provide adjacent photovoltaic modules 2 connect to.

The invention now provides that at a decentralized monitoring device 13 (each) to the plugs / sockets 18 complementary input plug and / or socket 19, 20 is provided so that the decentralized monitoring device 13 can be easily mated with the relevant photovoltaic module 2 ,

On the other hand, the decentralized monitoring device 13 also has two output plugs and / or sockets 21, 22, as shown in FIG. These assume the same function as the modular plugs 18 in the absence of monitoring device 13, that is, they are connected to adjacent module monitoring units 2, 13, for example by cable bridges 23.

4, an input terminal 19 of the decentralized monitoring device 13 is directly connected to an output terminal 21, that is looped through. In contrast, a shunt 24 is looped between the other two inputs and outputs 20, 22, at which the module current causes a (small) voltage drop, the tapped and is converted by an analog-to-digital converter 25 into a (binary) digital value I.

Between the two output terminals 21, 22 a voltage divider 26 is further connected to produce a voltage proportional to the module voltage measurement voltage. In this case, the output terminal 22 serves as a common Meßbezugspunkt for the analog voltage values for the module current and the module voltage. The voltage across the connected resistor 27 of the voltage divider 26 serves as a measured value for the module voltage and is converted in a downstream analog-to-digital converter 28 in a (binary) digital value U.

Furthermore, a sensor for measuring or detecting the temperature T of a photovoltaic module 2 can be provided in the monitoring device 13, and / or a sensor for measuring or detecting the light radiation Q incident on a photovoltaic module 2, and / or a sensor for measuring or detecting the ambient brightness H of a photovoltaic module 2, and / or a sensor for measuring or detecting the movement B or acceleration A of a photovoltaic module 2. These signal values T ₁ Q, H ₁ B and / or A are converted into a (binary) digital value.

The digital values U and I ₁ as well as possibly also T ₁ Q ₁ H, B and / or A ₁ reach a digital processing block 29 in the context of the decentralized monitoring device 13. This processing block 29 is powered by an energy store 30, preferably in the form of a rechargeable battery or Condenser, supplied with a positive operating voltage V ⁺ . The energy storage 30 is charged by the voltage of the photovoltaic module 2; an intermediate diode 31 prevents the energy storage 30 from discharging in the dark.

In the digital signal processing block 29 there is a memory for storing the measured values U, I for voltage and current as well as possibly for Storage of further information, for example temperature T, light radiation intensity Q, ambient brightness H, movement B and / or acceleration A, as well as a specific for the monitor 13 code C ₁ , C ₂ , etc., which this from the other, in particular adjacent monitoring devices 13th makes distinguishable.

Furthermore, a timer can be provided in the signal processing block 29 in order to transmit the stored information Ci, U, I ₁ T ₁ Q ₁ H ₁ B and / or A to the central monitoring station 14 or to a neighboring monitoring device 13 after a preset time interval ,

For this purpose, the monitoring device 13 is an antenna 32, which is preferably designed as a pure transmitting antenna, but could also be designed as a transmitting and receiving antenna.

In an upstream of the antenna 32 high-frequency part 33 is an oscillator or other, an oscillating signal generating circuit whose oscillating signal, the information C ₁ , U ₁ 1, T, Q, H, B and / or A are aufmoduliert, for example. by pulse modulation (PM) or pulse code modulation (PCM) or amplitude modulation (AM) or frequency modulation (FM) _1, and finally as a message or telegram with the content Ci U _C i, _C l i. Tci, Qci, H _C i, B _C i and / or Aa paid off via the antenna 32.

This message is collected by an antenna 34 of the central monitoring station 14, demodulated, and the information contained is buffered and evaluated. For example. can be determined from two values U _n , I _{n of} a module 2 by multiplying a power value P _n and also cached. Another method of operation envisages collecting the signal radiated by the antenna 32 of the first monitoring device 13 in an adjacent monitoring device 13, which is identical to a different code value C _2, and demodulating it in the local HF circuit 33 of the adjacent monitoring device 13; when the thus determined codeword C ₁ meets a certain requirement, for example, C ₁ = C ₂ -. 1, the received information U _C i, lci, T _C i, QCI, H _C1, B _C i and / or Aci optionally ., and finally a following telegram is compiled with the information: C ₁ , U _C1 , I _C1 , [T _C1 ], [Q _C i], [H _C i], [B _C i], [Aa]; C ₂ , U _C2 , Ic2, Fc ₂ ]. [Qcd, IHc ₂ ], IB _C2 ], [Ac ₂ ], with one or more of the parenthesized sizes being optional, depending on the embodiment. This telegram is in turn emitted and recovered by another monitoring device 13 and supplemented with information: C ₁ , U _C i, lci, U]; C ₂ , U _C2 , I _C 2, [•••]; C ₃ , U _C3 , Ics. [ "•]; etc. After passing through all the monitoring devices, a group telegram has been generated in this way, which contains information on all the monitored photovoltaic modules 2 and their respective "address" C _n This complete group telegram is then picked up by the antenna 34 of the central monitoring station 14, demodulated, and the For example, a power value P _n can be determined from two values U _n , I _{n of} a module 2 by multiplication and also buffered.

In the control center 14, an average value U _M , I _M , P _M is then formed from all approximately simultaneously received voltage values U and from all approximately simultaneously received current values I and possibly from all power values P and the deviation AU _n , Al _n , ΔP _n the parameters U _n , I _n , P _{n of} each module 2 are determined:

ΔU _n = U _M - U _n

Δl _n = I _M - I _n ΔP _n = P _M - Pn Particularly significant deviation AU _n , Al _n , AP _{n of} one or more photovoltaic modules 2 are thus detected and assigned to the respective photovoltaic module (s) 2.

Furthermore, it can be concluded on the basis of (further) plausibility checks, which could possibly be the cause of a suspected malfunction.

Then a message is generated, for example. "Photovoltaic module No. 738 defective" or "Photovoltaic module No. 738 presumably stolen", and this message can be forwarded in urgent cases to a person or organization, for example via an interface 35 to the telephone network. In very urgent cases, further actions can be taken, for example, a siren be turned on or the inverter 11 are turned off to keep a disturbance from the network 6. Finally, the messages as well as possibly further information are stored in a data memory, in particular in a mass memory, for documentation purposes.

LIST OF REFERENCE NUMBERS

Photovoltaic system 26 Voltage divider

Photovoltaic module 27 resistance

Power line 28 Analog-to-digital converter

Power line 29 digital processing block

Control center 30 Energy storage

Power grid 31 diode

Bypass diode 32 antenna

Wiring harness 33 RF circuit

Generator connection box 34 antenna

Main switch 35 interface

inverter

monitoring system

monitoring device

monitoring station

positive pole

minuspol

electric wire

Male / Female

Input plug / bush

Output Connector / bush

cable bridge

shunt

Analog to digital converter

Claims

claims

1. Device for monitoring individual photovoltaic modules (2) of a photovoltaic system (1), wherein in and / or at several

Photovoltaic modules (2) each means (13) for determining and / or evaluation of electrical parameters of a photovoltaic module (2), in particular of voltage U and / or current I _{1 is} connected, and wherein at least one means (13) for determining and / or Evaluation of electrical parameters of a photovoltaic module (2) to a

Central (14) for the purpose of transmitting information is coupled to this, and further wherein the information transmission from a device (13) for determining and / or evaluation of electrical parameters of a photovoltaic module (2) on wireless way and not permanently, so without interruption, but Intervallweise, characterized in that the information transmission without changing the frequency spectrum of an output of the photovoltaic module (2) takes place and by means of electromagnetic waves, wherein an oscillating signal generated in the device, the information to be transmitted are modulated and finally emitted via an antenna (32) become.

2. Apparatus according to claim 1, characterized by means (13) for measuring or detecting the temperature of a photovoltaic module (2).

3. A device according to any one of claims 1 or 2, characterized by means (13) for measuring or detecting the incident on a Photovoltaikmodυl (2) light radiation.

4. Device according to one of claims 1 to 3, characterized by means (13) for measuring or detecting the ambient brightness of a photovoltaic module (2).

5. Device according to one of the preceding claims, characterized by means (13) for measuring or detecting the movement of a photovoltaic module (2).

6. Device according to one of the preceding claims, characterized by one or more means for converting the measurement results into digital values and for providing the same in serial or parallel form.

7. Device according to one of the preceding claims, characterized in that the transmission of information about the

Parameter of a photovoltaic module (2) is independent of a request from a control center (14), but spontaneously or triggered by adjacent, decentralized monitoring devices (13), in particular by signals received therefrom.

8. Device according to one of the preceding claims, characterized in that the transmission of information unidirectionally from a photovoltaic module (2) to a control center (14).

9. Device according to one of the preceding claims, characterized in that the transmission of information from different photovoltaic modules (2) does not take place simultaneously.

10. Device according to one of the preceding claims, characterized in that the transmission of information from the

Photovoltaic modules (2) to a central station (14) takes place asynchronously.

11. Device according to one of the preceding claims, characterized by an oscillator for generating the oscillating signal.

12. Device according to one of claims 1 to 10, characterized by a block for the cyclical output of a sequence of signal values of a periodic, preferably sinusoidal curve to a downstream digital-to-analog converter for generating the oscillating signal.

13. Device according to one of the preceding claims, characterized in that the frequency of the oscillating signal in some, several or all photovoltaic modules in the same radio band, in particular in the same channel.

14. Device according to one of the preceding claims, characterized in that the frequency of the oscillating signal is 100 MHz or above, preferably at 200 MHz or above, in particular at 400 MHz or above.

15. Device according to one of the preceding claims, characterized in that the frequency of the oscillating signal is at or below 1,500 MHz, preferably at 1,200 MHz or below, in particular at 1,000 MHz or below.

16. Device according to one of the preceding claims, characterized by a module for modulating the oscillating signal with a pulse modulation method, for example. A pulse amplitude modulation method (PAM), or a pulse-code modulation method (PCM) ₁ or a

Pulse frequency modulation (PFM), in particular by means of frequency shift keying (FSK), or a Pulse phase modulation (PPM) method, or a

Pulse Width Modulation (PWM), or a

Pulse Pause Modulation Method (PPM).

17. Device according to one of the preceding claims, characterized by a module for modulating the oscillating signal with an information signal of a length of 2 or more data words per measurement sequence, preferably with an information signal of a length of 3 or more data words per measurement Sequence, in particular with an information signal of a length of 4 or more data words per measurement sequence.

18. Device according to one of the preceding claims, characterized by a module for modulating the oscillating signal with a data or baud rate of 2000 baud or more, preferably 4000 baud or more, in particular 8000 baud or more.

19. Device according to one of the preceding claims, characterized by at least one device for reducing or switching off the transmission power of the oscillating signal in the phases between the transmission of data.

20. Device according to one of the preceding claims, characterized by a device for reducing or

Switching off the transmission power of the oscillating signal for a "short" transmission interval of 0.2 seconds or more, preferably for an interval of 0.5 seconds or more, in particular for an interval of 1 second or more.

21. Device according to one of the preceding claims, characterized by a device for reducing or Switching off the transmission power of the oscillating signal for a "long" transmission interval of 2 seconds or more, preferably for an interval of 5 seconds or more, in particular for an interval of 10 seconds or more.

Apparatus according to claim 19 when appended to claim 20, characterized in that the means for a "short" transmission interval and for a "long" transmission interval following a data transmission are alternately activated.

23. Device according to one of the preceding claims, characterized in that the information transmission takes place without changing the frequency response of an output variable of the relevant photovoltaic module (2).

24. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) with a photovoltaic module (2) is integrated.

25. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) to the electrical connections (18) of a photovoltaic module (2) coupled or can be coupled.

26. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) between the electrical connections (18) of a

Photovoltaic module (2) and from there further electrical cable (23) is connected.

27. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) has at least three electrical connections, preferably at least four terminals (19-22 ).

28. Device according to one of the preceding claims, characterized in that a device (13) for determining and / or evaluation of electrical and / or other parameters of a

Photovoltaic module (2) together with the monitored photovoltaic module (2) form a jointly connectable module.

29. The device according to claim 28, characterized in that a device (13) for determining and / or evaluating electrical and / or other parameters of a photovoltaic module (2) is designed such that the power-related combination of several modules, each consisting of a photovoltaic module ( 2) and a device (13) for determining and / or evaluating electrical parameters of this photovoltaic module (2), both in parallel and in series.

30. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical parameters of a photovoltaic module

(2) has a rechargeable energy storage device (30) for its own power supply, for example a battery, capacitor or the like, which is charged during solar irradiation and generation of electricity by the relevant solar module (2).

31. The device according to claim 30, characterized in that the storage capacity of a rechargeable energy store (30) is sufficient, so that the storable during the day charge for the nightly operation of the device (13) is sufficient.

32. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a

Photovoltaic module (2) via at least one antenna (32) has to

Sending and possibly receiving radio signals.

33. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) has at least one device (24,26) for imaging the module voltage and / or of the module current to (each) an approximately proportional current and / or voltage value.

34. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) has at least one device for

Multiplying an approximately proportional to the module voltage current and / or voltage value with an approximately proportional to the module current current and / or voltage value, for the purpose of determining the power produced by the photovoltaic module (2).

35. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) has at least one device for integrating a to the module voltage and / or the module current and / or to the module power approximately proportional power and / or Voltage value, preferably over respectively predetermined time intervals.

36. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) has at least one device for storing Qe) one to the module voltage and / or to the module current and / or to the module power approximately proportional and / or (intervalwise) integrated, digitized value.

37. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical and / or other parameters of a photovoltaic module (2) comprises at least one device for

Saving a module- and / or device-specific code, for example a module- and / or device-specific number (Ci ₁ C ₂ ).

38. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical parameters of a photovoltaic module (2) has at least one gain element to produce the output signal of the oscillator with the required transmission power and / or to increase the required transmission power.

39. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluating electrical parameters of a photovoltaic module (2) has at least one device for modulating a transmission signal with a module or device-specific code, eg. a module- or device-specific number (C ₁₁ C ₂ ), and / or for its modulation with Qe) one to the module voltage and / or to the Module current and / or to the module performance about proportional and / or (intervalwise) integrated, digitized value.

40. Device according to one of the preceding claims, characterized in that at least one device (13) for determining and / or evaluation of electrical parameters of a photovoltaic module

(2) at least one device for demodulating a

Receive signal to gain its transmitted information.

41. Apparatus according to claim 40, characterized in that at least one device (13) for determining and / or evaluating electrical parameters of a photovoltaic module (2) has at least one device for buffering the information content of a received signal, preferably its transmitted information in a following Transmission step the carrier signal of the

Oscillator for the purpose of radiation aufzumodulieren again.

42. Device according to one of the preceding claims, characterized by a central receiving station (14) for receiving one or more information of the device (s) (13) for

Determination and / or evaluation of electrical parameters of individual photovoltaic modules (2).

43. Apparatus according to claim 42, characterized in that the central receiving station (14) is coupled via lines or by radio with one or more spatially remote antenna units, each communicating with different decentralized devices (13).

44. Apparatus according to claim 42 or 43, characterized in that the central receiving station (14) comprises means for evaluating the received information.

45. Device according to one of claims 42 to 44, characterized in that the central receiving station (14) comprises means (35) for the delivery and / or forwarding of signals.

46. A method for monitoring individual photovoltaic modules (2) of a photovoltaic system (1), in particular using a device according to one of the preceding claims, characterized in that in and / or at several photovoltaic modules (2) each one or more electrical parameters, in particular

Voltage and / or current, determined and / or evaluated and these and / or information obtained therefrom to a central office (14) are transmitted.

47. The method as claimed in claim 46, characterized in that a module-specific code (C ₁₁ C ₂ ) is added during the transmission of each piece of information to the control center (14), so that the relevant information in the control center (14) is clearly assigned to a specific photovoltaic module ( 2) can be assigned.

48. The method according to claim 46 or 47, characterized in that the received information in the central office (14) are compared with each other and / or with a mean value formed therefrom, for example, to determine significant deviations of individual photovoltaic modules (2).

49. The method according to any one of claims 46 to 48, characterized in that upon detection of significant deviations in one or more photovoltaic modules (2) a message is generated.

50. The method according to any one of claims 46 to 49, characterized in that messages about significant deviations for documentation purposes are collected and / or stored.

51. The method according to any one of claims 46 to 50, characterized in that messages about significant deviations to one or more predetermined recipient (s) are sent.

52. The method according to any one of claims 46 to 51, characterized in that messages about significant deviations to

Triggering of security measures can be used, for example, to turn on a siren.

53. The method according to any one of claims 46 to 52, characterized in that information also between decentralized

Means (13) for monitoring parameters (each) of a photovoltaic module (2) are transmitted.

54. The method according to any one of claims 46 to 53, characterized in that the transmission of information from / to a plurality of decentralized devices (13) for monitoring parameters (each) of a photovoltaic module (2) takes place on a common carrier medium, in particular on a common transmission channel.

55. The method according to any one of claims 46 to 54, characterized in that the transmission of information from / to a plurality of decentralized devices (13) for monitoring parameters Qe) of a photovoltaic module (2) not on the energy-carrying lines (3,4, 8,23) of the photovoltaic system (1).