WO2011074009A1

WO2011074009A1 - Power management system

Info

Publication number: WO2011074009A1
Application number: PCT/IN2010/000818
Authority: WO
Inventors: Claes Otto Anders Hansson
Original assignee: Nsg Networks Private Limited
Priority date: 2009-12-16
Filing date: 2010-12-16
Publication date: 2011-06-23
Also published as: BR112012015003A2; CA2784831A1; EP2514067A1; RU2012125167A

Abstract

The present disclosure to provide a system and method for power management thereof, in which a primary source and one or more secondary power sources are combined to supply power to the load in a manner that the maximum power shared is by the primary power source.

Description

POWER MANAGEMENT SYSTEM

Technical Field

The present disclosure relates to power management, and more particularly, but not limited to effective power management in systems incorporating multiple power sources. Glossary

-Primary power source - is a preferred power source in a power system comprising multiple power sources. Secondary power source - is not a preferred power source but merely provides supplementary power to the load in a power system comprising multiple power sources.

Background

Several applications include multiple power sources including grid power supply and renewable power sources. However, currently effective utilization of renewable power energy plays little or no part in design of power supply systems. Even if these are included, such power supply systems do not have effective power management.

Figure 1 illustrates a block diagram showing a power management system according to conventional art. In the given figure, block 101 represents a solar power source and block 102 represents an AC/DC power source. Output power generated by the solar power source 101 and the AC/DC power source 102 is combined together to feed a load 103. A charge controller (or a battery) 104 accepts output power generated by solar and AC/DC power source 101, 102 simultaneously while delivering an accurately defined input voltage and current to the load 103. Further, a current sensor 105 is provided to measure the output current of AC/DC power source 102 and accordingly regulate the output of the AC/DC power source 102 independent of the solar power source 101. Such a regulation is implemented independently of output power generated by the solar power source 101. In existing multiple power source systems there is no arrangement for combining the outputs of the multiple power sources in a manner that ensures a maximum share of ower supply drawn from a preferred power source.

Summary

It is an object of the present disclosure to provide a system and method of power management in which output power generated by a primary source and one or more controllable secondary power sources is combined to supply power to the load such that the maximum share of power supplied to the load is provided by the primary power source.

An embodiment of the present disclosure illustrates a power management system comprising: a primary power source; one or more controllable secondary power sources; said primary and controllable secondary power sources having their outputs operatively combined to supply power to a load; and a power sharing control unit configured to ensure that maximum share of power provided to the load is supplied by the primary power source. Further, power sharing control unit comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled: to one or more control inputs of each said controllable secondary power source; one or more current reference inputs of each said controllable secondary power source; or one or more voltage reference inputs of each said controllable secondary power source.

Another embodiment of the present disclosure illustrates a power conditioner comprising: a primary power source; one or more controllable secondary power sources; said primary and secondary power sources having their outputs operatively combined to supply power to a load; and a power sharing control unit configured to ensure that maximum share of power provided to the load is supplied by the primary power source. Further, the power sharing control unit comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled: to one or more control inputs of each said controllable secondary power source; one or more current reference inputs of each said controllable secondary power source; or one or more voltage reference inputs of each said controllable secondary power source.

Another embodiment of the present disclosure illustrates a base transceiver station of a cellular network comprising a power management system Said power management system comprises: a primary power source; one or more controllable secondary power sources; said primary and secondary power sources having their outputs operatively combined to supply power to a load; and a power sharing control unit configured to ensure that maximum share of power provided to the load is supplied by the primary power source. Further, power sharing control unit comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled: to one or more control inputs of each said controllable secondary power source; one or more current reference inputs of each said controllable secondary power source; or one or more voltage reference inputs of each said controllable secondary power source.

According to another embodiment of the present disclosure, a method of power management in a power sharing scheme is described where said method comprises combining output power generated by a primary power source and one or more controllable secondary power sources to provide input power to a load, said method comprising: sensing the load current and/or the current supplied by the primary power source; and automatically adjusting one or more control inputs of each said controlled secondary power source so as to maximize the contribution of the primary power source to the power input to the load. Further, the power sharing scheme reduces the contribution of each said controllable secondary power source to the power input to the load, by adjusting: a current sense signal supplied to control input of each said controllable secondary power source, a current reference signal supplied to control input of each said controllable secondary power source, or a voltage reference signal supplied to control input of each said controllable secondary power source.

Brief Description of the Drawings The present disclosure explains the various embodiments of the instant disclosure in the following description, taken in conjunction with the accompanying drawings, wherein: FIGURE 1 illustrates a block diagram showing a power management system according to conventional art.

FIGURE 2 illustrates a block diagram of a power management system according to an embodiment of the present disclosure.

FIGURE 3 illustrates a block diagram of a power management system according to yet another embodiment of the present disclosure.

FIGURE 4 illustrates a block diagram of a power management system according to yet another embodiment of the present disclosure.

FIGURE 5 illustrates a block diagram of a power management system according to yet another embodiment of the present disclosure. FIGURE 6 illustrates a flow chart of a method for power management among multiple power sources according to an embodiment of the present disclosure.

Detailed Description

Exemplary embodiments now will be described with reference to the accompanying drawings. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. The terminology used in the detailed description of the .particular exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting. In the drawings, like numbers refer to like elements. The specification may refer to "an", "one" or "some" embodiment(s) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other emb'odiments.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms "includes", "comprises", "including" and/or "comprising" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. Furthermore, "connected" or "coupled" as used herein may include operatively connected or coupled. As used herein, the term "and/or" includes any and all combinations and arrangements of one or more of the associated listed items.

Unless otherwise defined, all terms (including technical and scientific terms) used"" herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

"Wireless communication system" includes any communication system or any combination of different communication systems. The communication system may be a fixed communication system or a wireless communication system or a communication system utilizing^' both fixed networks and wireless networks. The protocols used, the specifications of communication systems, servers and user terminals, especially in wireless communication, develop rapidly. Such development may require extra changes to an embodiment. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict the embodiment. The figures depict a simplified structure only showing some elements and functional entities, all being logical units whose implementation may differ from what is shown. The connections shown are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art: that the structure may also comprise other functions and structures. It should be appreciated that the functions, structures, elements and the protocols used in communication are irrelevant to the present disclosure. Therefore, they need not be discussed in more detail here.

Also, all logical units described and depicted in the figures include the software and/or hardware components required for the unit to function. Further, each unit may comprise within itself one or more components which are implicitly understood. These components may be operatively coupled to each other and be configured to communicate

Figure 2 illustrates a block diagram of a power management system according to an embodiment of the present disclosure. In the given figure, block 201 represents a primary power source i.e. a solar power source and block 202 represents a controllable secondary power source i.e. an AC/DC utility grid power source. Output power generated by the solar power source 201 and the AC/DC power source 202 is combined together to feed a load 203. A charge controller (or a battery) 204 accepts output power generated by the solar, and AC/DC power source 201, 202 simultaneously while delivering an · accurately defined input voltage and current to the load 203. Further, a load current sensor 205 measures the load current and regulates the AC/DC power source 202 independent of the solar power source 201. It will be apparent to those having ordinary skill in this art that the concept is not limited to two input power sources and can be extended to several input power sources, but presence of at least one primary power source is imperative for all of the possible embodiments.

Further, according to an embodiment of the present disclosure, the power sharing is the result of a current sharing control mechanism where the current originating from the secondary power source i.e. AC/DC power source 202 is minimized, while the solar power source 201 delivers maximum amount of available power at every given instant. The maximum amount of available power may be the entire output power being generated by the solar power source. It may also refer to a value less than the entire output power as the entire output power being generated by the solar power source 201 may not be required by the load 203 or any energy storage device that may be connected to the charge controller. Moreover, due to addition of a signal indicative of current from another power source, the AC/DC power source does not merely maintain itself at a well defined maximum AC/DC output current limit, but reduces the aforementioned limit so that the sum of solar and AC/DC output current stays constant. For example- during night time the net total charging and load current is delivered only by the AC/DC power supply by maximizing its supply as solar power is not available at that time. During daytime, the AC/DC power source 202 is fed a signal indicative of the total charging current to reduce contribution from the AC/DC power supply and allow the solar power source 201 to operate to its maximum current.

Figure 3 illustrates a block diagram of a power management system according to yet another embodiment of the present disclosure. In the given figure, a load current sensor 301 is connected to one or more current reference inputs of each said controllable secondary power source 202. The current sensor senses the current reference signal and controls the AC/DC power source. The output power generated by the AC/DC power source is reduced in proportion to increase in output power generated by the solar power source during the daytime. Thus, providing the true value of the current reference signal and increasing the reliability of power management system.

Figure 4 illustrates a block diagram of a power management system according to yet another embodiment of the present disclosure. In the given figure, a load current sensor 401 is connected to one or more voltage reference inputs of each said controllable secondary power source 202. The current sensor senses the voltage reference signal and controls the AC/DC power source. The voltage reference for the controllable AC/DC power source is reduced such that both the AC/DC voltage and current reduce when current of the solar power source increases. This scheme provides an active load sharing during the entire operating range from idle condition to full power. Thus, providing the true value of the voltage reference signal and increasing the reliability of power management system.

Figure 5 refers to a block diagram of a power management system according to yet another embodiment of the present disclosure. In the given figure, a control unit 501 is provided to control the controllable secondary power source 202 based on the feedbacks provided by a primary source current sensor 502 and the load current sensor 503. Based upon the feedback provided by the primary current sensor and the load current sensor, control unit controls the controllable secondary power source and adjusts the overall current such that sum of currents provided by both power sources is maintained constant. Thus, effective power management and overall reliability of the system is ensured.

A preferred embodiment of the present disclosure describes a Base Transceiver Station (BTS) of a. cellular communication network comprising a power management system, wherein said power management system includes: a primary power source; one or more controllable secondary power sources; and output power generated by the primary power source and the controllable secondary power sources is combined to supply power to a load. The embodiment further comprises a power sharing control unit configured to ensure that maximum share of power provided to the load is supplied by the primary power source. Moreover, a load current sensor and/or a primary source current sensor, is provided: to sense current signals from one or more control inputs of each controllable secondary power source, to sense current reference signal or to sense voltage reference signal of each controllable secondary power source. Accordingly, the controllable secondary power source is adjusted. An embodiment of a method for a power management among multiple power sources is described in Figure 6. The method is illustrated as a collection of blocks in a logical flow graph, which represents a sequence of operations that can be implemented in hardware, software, or a combination thereof. The order in which the process is described is not intended to be construed as a limitation, and any number of the described blocks can be combined in any order to implement the process, or an alternate process.

Figure 6 illustrates a flow chart of a method for power management among multiple power sources according to an embodiment of the present disclosure. The method of power management in a power sharing scheme includes combining output power generated by a primary power source 201 and one or more controllable secondary power sources 202 as referred in figure 2, to provide power to a load. Accordingly in step 601, the load current and/or the current supplied by the primary power source are sensed by current sensors. Further, in step 602, one or more control inputs of each said controllable secondary power source are adjusted to maximize the contribution by the primary source in the power fed to the load. Further, the power sharing scheme reduces contribution of each said controllable secondary power source by adjusting: a current sense signal supplied to its control input, a current reference signal supplied to its control input or a voltage reference signal supplied to its control input.

Embodiments of the system and method of power management as disclosed in the^" present disclosure provide an efficient power control and sharing mechanism. The secondary power source which is not a preferred source of power supply reduces its contribution to supply power to load during the day time when the sunlight is in abundance and allows solar power source to supply maximum power. Hence, the cost of power supply is also reduced up to a great extent and even the power is conserved from the secondary power source.

The present disclosure is applicable to all types power systems used at several places to supply power to a variety of loads such as residential, industrial, communication networks etc.

It will be apparent to those having ordinary skill in this art that various modifications and variations may be made to the embodiments disclosed herein, consistent with the present disclosure, without departing from the spirit and scope of the present disclosure. Other embodiments consistent with the present disclosure will become apparent from consideration of the specification and the practice of the description disclosed herein.

Claims

We claim:

1. A power management system comprising:

- a primary power source;

- one or more controllable secondary power sources;

► said primary and secondary power sources having their outputs operatively combined to supply power to a load; and

- a power sharing control mechanism that operates to ensure that maximum share of power provided to the load is supplied by the primary power source.

2. The system as claimed in claim 1, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more control inputs of each said controllable secondary power source.

3. The system as claimed in claim 1, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more current reference inputs of each said controllable secondary power source.

4. The system as claimed in claim 1, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more voltage reference inputs of each said controllable secondary power source.

5. The system as claimed in claim 1, wherein said primary power source is a solar power source.

6. The system as claimed in claim 1 , wherein said primary power source is a wind power source.

7. The system as claimed in claim 1, wherein said primary power source is a hydroelectric power source.

8. The system as claimed in claim 1, wherein at least^" one said secondary power source is an AC/DC power supply.

9. A power conditioner comprising:

a primary power source; - one or more controllable secondary power sources; said primary and secondary power sources having their outputs operatively combined to supply power to a load; and

power sharing control mechanism that operates to ensure that maximum share of power provided to the load is supplied by the primary power source.

10. The power conditioner as claimed in claim 9, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more control inputs of each said controllable secondary power source.

1 1. The power conditioner as claimed in claim 9, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more current reference inputs of each said controllable secondary power source.

12. The power conditioner as claimed in claim 9, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more voltage reference inputs of each said controllable secondary power source.

13. The power conditioner as claimed in. claim 9, wherein said primary power source is a solar power source.

14. The power conditioner as claimed in claim 9, wherein said primary power source is a wind power source.

15. The power conditioner as claimed in claim 9, wherein said primary power source is a hydroelectric power source.

16. The power conditioner as claimed in^" claim 9, wherein at least one said secondary power source is an AC/DC power supply.

17. A Base Transceiver Station of a cellular communication network includes a power management system, said power management system comprising:

- a primary power source;

- one or more controllable secondary power sources; said primary and secondary power sources having their outputs operatively combined to supply power to a load; and

18. The Base Transceiver Station as claimed in claim 17, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more control inputs of each said controllable secondary power source.

19. The Base Transceiver Station as claimed in claim 17, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more current reference inputs of each said controllable secondary power source.

20. The Base Transceiver Station as claimed in claim 17, wherein said power sharing control mechanism comprises a load current sensor and/or a primary source current sensor, said sensors being operatively coupled to one or more voltage reference inputs of each said controllable secondary power source.

21. The Base Transceiver Station as claimed in claim 17, wherein said primary power source is a solar power source.

22. The Base Transceiver Station as claimed in claim 17, wherein said primary power source is a wind power source.

23. The Base Transceiver Station as claimed in claim 17, wherein said primary power source is a hydroelectric power source.

24. The Base Transceiver Station as claimed in claim 17, wherein said secondary power source is an AC/DC power supply.

25. A method of power management in a power sharing scheme comprising a combination of a primary power source and one or more controllable secondary power sources to provide power to a load, said method comprising: sensing the load current and/or the current supplied by the primary power source; and automatically adjusting one or more control inputs of each said controlled secondary power source so as to maximize the contribution of the primary source.

26. The method as claimed in claim 25, wherein said power sharing scheme operates to reduce the contribution of each said controllable secondary power source by adjusting a current sense signal supplied to its control input.

27. The method as claimed in claim 25, wherein said power sharing scheme operates to reduce the contribution of each said controllable secondary power source by adjusting a current reference signal supplied to its control input.

28. The method as claimed in claim 25, wherein said power sharing scheme operates to reduce the contribution of said controllable secondary power source by adjusting a voltage reference signal supplied to its control input.