Distributed power supply system and energy regulation method based thereon

Abstract

The present invention discloses a distributed power supply system and an energy regulation method based thereon, wherein the distributed power supply system comprises a plurality of energy modules, a plurality of power conversion modules and a bus voltage controller, wherein the plurality of energy modules are electrically connected to a DC bus via corresponding power conversion modules, the bus voltage controller is connected to the plurality of power conversion modules, and the energy regulation method comprises: the power conversion module obtains at least one energy state parameter of the corresponding energy module, and calculates the cardinality signal of each power conversion module; the bus voltage controller generates a normalized control signal based on the bus voltage of the DC bus, and transmits the control signal to each power conversion module; the power conversion module obtains the control given quantity of each power conversion module according to the control signal and the cardinality signal, and regulates the corresponding energy module according to the control given quantity. The present invention can optimize the power distribution of multiple energy groups while controlling voltage / current.

Description

Technical Field

[0001] The invention relates to a distributed power supply system and an energy regulation method based thereon. Background Art

[0002] Fuel cell power supply system has the advantages of high efficiency, high power density, modularization, long life, etc., and is an important direction for future energy development. For example, the existing SOFC (Solid Oxide Fuel Cell) can achieve a comprehensive efficiency of 80% to 90%.

[0003] However, existing fuel cells have problems such as low output voltage, large fluctuation of DC voltage, and poor adaptability to low-frequency ripple, so DC / DC converters are needed for front-end boost and voltage regulation control. However, during the operation of high-power fuel cell power supply systems, DC / DC converters mainly control the DC bus voltage, and have poor current control and regulation capabilities for fuel cells.

[0004] On the one hand, in order to make each fuel cell module in the fuel cell power supply system share the output power equally, DC / DC converters usually adopt centralized communication and droop control methods. However, centralized communication methods have the defects of slow response speed and low reliability; and in droop control, the bus voltage accuracy and the current balance between each fuel cell module often need to be compromised. In order to achieve a higher bus voltage accuracy, the current imbalance between each fuel cell module still exists.

[0005] On the other hand, due to factors such as manufacturing process, age, and health status, there are differences in power generation efficiency, output voltage, and stack temperature among multiple groups of fuel cell modules. It is necessary to find ways to effectively utilize the characteristic parameters of fuel cells to optimize the operation of the fuel cell power supply system. Summary of the invention

[0006] The purpose of the present invention is to provide a distributed power supply system and an energy regulation method based thereon, which can optimize the power balance and energy allocation of multiple energy modules while realizing bus voltage / current control.

[0007] In order to achieve the above-mentioned object, the present invention provides an energy regulation method based on a distributed power supply system, which is characterized in that the distributed power supply system includes a plurality of energy modules, a plurality of power conversion modules and a bus voltage controller, the plurality of energy modules are electrically connected to a DC bus via the corresponding power conversion modules, the bus voltage controller is connected to the plurality of power conversion modules, and the energy regulation method includes:

[0008] The power conversion module obtains at least one energy state parameter of the corresponding energy module and calculates the cardinality signal of each power conversion module;

[0009] The bus voltage controller generates a normalized control signal based on the bus voltage of the DC bus, and transmits the control signal to each of the power conversion modules;

[0010] The power conversion module obtains the control given quantity of each power conversion module according to the control signal and the base signal, and adjusts the corresponding energy module according to the control given quantity.

[0011] In one embodiment of the present invention, the power conversion module obtains the energy status information from the corresponding energy module at a first update frequency; the bus voltage controller transmits the normalized control signal to each power conversion module at a second update frequency, wherein the second update frequency is greater than the first update frequency.

[0012] In one embodiment of the present invention, the power conversion module obtains the energy status information through digital communication at the first update frequency, and the bus voltage controller transmits the control signal to each power conversion module through broadcast communication at the second update frequency.

[0013] In one embodiment of the present invention, the power conversion module further obtains the rated output value of the corresponding energy module, and calculates the cardinality signal of each power conversion module according to the rated output value and the energy state parameter.

[0014] In one embodiment of the present invention, the power conversion module calculates the quotient of the energy state parameter of the corresponding energy module and the average of the energy state parameters of the multiple energy modules, and multiplies it by the rated output value to obtain the cardinality signal of each power conversion module.

[0015] In one embodiment of the present invention, the energy status parameter is at least one of the output voltage value of the energy module, the output voltage system set value, the output current set value, the temperature detection value, the power detection value, the conversion efficiency calculation value, the charge state detection value of the energy module, and the health level detection value of the energy module; and / or the control signal is a normalized current or power value.

[0016] In one embodiment of the present invention, the power conversion module is a DC / DC conversion module; and / or the energy module is a fuel cell.

[0017] In order to achieve the above object, the present invention further provides a distributed power supply system, which is characterized in that it includes:

[0018] Multiple energy modules;

[0019] A plurality of power conversion modules, each electrically connecting the corresponding energy module to a DC bus, and

[0020] a bus voltage controller, communicating with the plurality of power conversion modules;

[0021] Wherein, the power conversion module obtains at least one energy state parameter of the corresponding energy module and forms a cardinality signal of each power conversion module;

[0022] The bus voltage controller generates a normalized control signal based on the bus voltage of the DC bus, and transmits the control signal to each of the power conversion modules;

[0023] The power conversion module obtains the control given quantity of each power conversion module according to the control signal and the base signal, and adjusts the corresponding energy module according to the control given quantity.

[0024] In another embodiment of the present invention, the power conversion module obtains the energy status information from the corresponding energy module at a first update frequency; the bus voltage controller transmits the control signal to each power conversion module at a second update frequency, wherein the second update frequency is greater than the first update frequency.

[0025] In another embodiment of the present invention, the power conversion module obtains the energy status information through digital communication at the first update frequency, and the bus voltage controller transmits the control signal to each power conversion module through broadcast communication at the second update frequency.

[0026] In another embodiment of the present invention, the energy status parameter is at least one of the output voltage value of the energy module, the output voltage system set value, the output current set value, the temperature detection value, the power detection value, the conversion efficiency calculation value, the charge state detection value of the energy module, and the health level detection value of the energy module; and / or the control signal is a normalized current or power value.

[0027] In another embodiment of the present invention, the power conversion module is a DC / DC conversion module; and / or the energy module is a fuel cell.

[0028] In another embodiment of the present invention, the DC bus is further connected to a power grid via an AC / DC conversion module.

[0029] In another embodiment of the present invention, the bus voltage controller is integrated into the AC / DC conversion module, or is independently arranged outside the AC / DC conversion module.

[0030] The present invention introduces a cardinality factor in the control of each power conversion module, and the energy module adopts a normalized regulation signal and sends it to multiple power conversion modules in a digital broadcasting manner, so that the distributed power supply system has good scalability, maintainability and rapid response performance. On the basis of satisfying the common bus voltage control and the basic balance of the output power of each energy module, the energy / power optimization regulation based on the operating status of each energy module is realized.

[0031] Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0033] Figure 1 It is a structural schematic diagram of the distributed power supply system of the present invention;

[0034] Figure 2 It is a flow chart of the energy regulation method of the distributed power supply system based on the present invention. DETAILED DESCRIPTION

[0035] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0036] When introducing the elements / components / etc. described and / or illustrated herein, the terms "a", "an", "the", "said", and "at least one" are used to indicate the presence of one or more elements / components / etc. The terms "comprises", "includes", and "have" are used to indicate an open-ended inclusive meaning and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc. Relative terms may be used in the embodiments, such as "upper" or "lower" to describe the relative relationship of one component of the icon to another component. It is understood that if the device of the icon is turned over so that it is upside down, the component described on the "upper" side will become the component on the "lower" side. In addition, the terms "first", "second", etc. in the claims are used only as labels and are not numerical limitations on their objects.

[0037] like Figure 1As shown, the distributed power supply system 100 of the present invention mainly includes a plurality of energy modules 10, a plurality of power conversion modules 20 and a bus voltage controller 30. The plurality of power conversion modules 20 respectively electrically connect the corresponding energy modules 10 to a DC bus 40, for example, Figure 1 Six fuel cell energy modules 11-16 are shown, which are electrically connected to corresponding power conversion modules 21-26, and these power conversion modules 21-26 are electrically connected to the DC bus 40. The bus voltage controller 30 communicates with the multiple power conversion modules 20 by wire or wireless.

[0038] Preferably, these power conversion modules 21-26 can be DC / DC conversion modules, and can be further connected to a power grid 50 through an AC / DC conversion module 31 via the DC bus 40. These energy modules 11-16 can be fuel cells, for example, including but not limited to lithium batteries. The bus voltage controller 30 can be integrated into the AC / DC conversion module 31, or independently arranged outside the AC / DC conversion module 31.

[0039] Combination Figure 1 ,like Figure 2 As shown, the energy regulation method of the distributed power supply system of the present invention includes:

[0040] In step S201, the power conversion module 20 obtains at least one energy state parameter of the corresponding energy module 10, and calculates the cardinality signal of each power conversion module 10;

[0041] In step S202, the bus voltage controller 30 generates a normalized control signal based on the bus voltage of the DC bus 40, and sends the control signal to each of the power conversion modules 20;

[0042] In step S203 , the power conversion module 20 obtains the control given quantity of each power conversion module 20 according to the control signal and the base signal, and adjusts the corresponding energy module 10 according to the control given quantity.

[0043] In the present invention, the step S202 and the step S203 may be performed at different times or at the same time. The power conversion module 20 may obtain the energy state information from the corresponding energy module 10 at a first update frequency through digital communication. The bus voltage controller 30 may send the normalized control signal to each of the power conversion modules 20 at a second update frequency through broadcast communication, and preferably, the second update frequency may be greater than the first update frequency.

[0044] In a preferred embodiment of the present invention, the first update frequency may be, for example, 10 Hz, which is usually determined by the time interval at which the energy state changes significantly; the second update frequency may be, for example, 1 kHz, which is usually determined by the control response time requirement of the bus voltage. Since the DC bus stores much less energy than the energy module, the change of its voltage state is more sensitive and faster than the change of the energy state parameter of the energy module. The appropriate selection of the update frequency can improve the overall performance of the distributed power supply system.

[0045] In one embodiment, the power conversion module 20 can also obtain the rated output value of the corresponding energy module 10, and calculate the cardinality signal of each power conversion module 20 according to the rated output value and the energy state parameter. For example, the power conversion module 20 can calculate the quotient of the energy state parameter of the corresponding energy module 10 and the average value of the energy state parameters of the multiple energy modules 10, and multiply it by the rated output value to obtain the cardinality signal of each power conversion module 20. Wherein, the cardinality signal is related to the energy state of each connection, and can be transmitted to each power conversion module through energy state information collection and communication, wherein the information collection and communication unit can be in the energy device (i.e., energy module) or in a device outside the energy device. The energy state parameters include but are not limited to the output voltage value of the energy module, the output voltage system given value, the output current given value, the temperature detection value, the power detection value, the conversion efficiency calculation value, the state of charge (SOC) detection value of the energy module, and at least one of the health level detection value of the energy module, which can be one or more factors that have restrictions or optimization requirements on the normal input or output power of the energy (i.e., the energy module), and can be obtained by each power conversion module from each energy device (i.e., the energy module) and the system device through communication calculation. Each power conversion module 20 can communicate with other components by adopting the RS485 serial communication standard, for example. The control signal is a normalized current or power value, which can be obtained by the bus voltage controller 30 detecting and error calculating the bus voltage of the DC bus 40, and its value is between -1 and 1, and is transmitted to each power conversion module 20 simultaneously via broadcast communication.

[0046] The present invention adopts a centralized bus voltage control mode. In the output control of the voltage / current or power of each power conversion module, the calculation of the output given value of each power conversion module is determined by the product of two input variables (i.e., the normalized control signal and the base signal). Energy module

[0047] The energy regulation method of the present invention and its advantages are described in detail below with reference to a specific embodiment. Specific embodiment 1:

[0049] A plurality of power conversion modules 20 are connected to a DC bus 40 and a plurality of energy modules 10 (e.g., lithium battery packs). A bus voltage controller 30 measures the bus voltage and generates a current or power control signal, which is sent in parallel to all power conversion modules 20 through digital communication. The bus voltage controller 30 can be integrated in a PCS (Power Conversion System, energy storage converter) module 31, or can be an independent external controller. To achieve fast communication control, the current command issued by the PCS is a normalized current value (-1 to 1); at the same time, the power conversion module 20 determines the base signal according to the current parameter and SOC (State of charge) parameter of the corresponding connected energy module 10. As a special case, the base signal can be the product of the rated current value of the energy module 10 and its SOC parameter, and the SOC parameter is equal to the quotient of the SOC value of the energy module 10 and the average SOC value of all battery packs.

[0050] In this way, the present invention introduces a cardinality factor in the control of each power conversion module, adopts a normalized adjustment signal, and sends it to multiple power conversion modules in a digital broadcasting manner. On the basis of satisfying the common bus voltage control and the basic balance of the output power of each energy module, the energy / power optimization adjustment based on the operating status of each energy module is realized, so that the distributed power supply system has good scalability, maintainability and fast response performance. The first update frequency is generally determined by the time interval at which the energy state of the energy module changes significantly. Taking the battery as an example, the SOC state update frequency of 10Hz is usually fast enough; the second update frequency is generally determined by the control response time requirement of the bus voltage. Taking the DC side of the inverter as an example, a voltage control quantity update frequency of 500Hz or higher is very necessary for the DC bus voltage stability and dynamic performance. The reason is that the DC bus stores much less energy than the energy module, so the change of its voltage state is more sensitive and faster than the change of the energy state parameter of the energy module. On the other hand, in a multi-energy integrated system, low-frequency energy status updates also allow the bus voltage controller to have more time to time-share the communications between multiple power conversion modules and multiple energy modules, which is conducive to low-cost and efficient use of communication resources and central processor time resources.

[0051] The exemplary embodiments of the present invention are specifically shown and described above. It should be understood that the present invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. An energy regulation method based on a distributed power supply system, characterized in that: The distributed power supply system includes a plurality of energy modules, a plurality of power conversion modules and a bus voltage controller, wherein the plurality of energy modules are electrically connected to a DC bus via corresponding power conversion modules, and the bus voltage controller is connected to the plurality of power conversion modules, and the energy regulation method includes: The power conversion module obtains at least one energy state parameter and a rated output value of the corresponding energy module, calculates the quotient of the energy state parameter of the corresponding energy module and the average value of the energy state parameters of the multiple energy modules, and multiplies the quotient by the rated output value to obtain the cardinality signal of each power conversion module; The bus voltage controller generates a normalized control signal based on the bus voltage of the DC bus, and transmits the control signal to each of the power conversion modules; The power conversion module obtains the control given quantity of each power conversion module according to the product of the control signal and the base signal, and adjusts the corresponding energy module according to the control given quantity.

2. The energy regulation method based on the distributed power supply system according to claim 1 is characterized in that: The power conversion module obtains the energy state information from the corresponding energy module at a first update frequency; The bus voltage controller transmits the normalized control signal to each of the power conversion modules at a second update frequency, wherein the second update frequency is greater than the first update frequency.

3. The energy regulation method based on the distributed power supply system according to claim 2 is characterized in that: The power conversion module obtains the energy status information via digital communication at the first update frequency, and the bus voltage controller transmits the control signal to each of the power conversion modules via broadcast communication at the second update frequency.

4. The energy regulation method based on a distributed power supply system according to claim 1, characterized in that: The energy status parameter is at least one of an output voltage value of the energy module, an output voltage system given value, an output current given value, a temperature detection value, a power detection value, a conversion efficiency calculation value, a charge state detection value of the energy module, and a health level detection value of the energy module; and / or The control signal is a normalized current or power value.

5. The energy regulation method based on a distributed power supply system according to claim 1, characterized in that: The power conversion module is a DC / DC conversion module; and / or the energy module is a fuel cell.

6. A distributed power supply system, characterized in that: include: Multiple energy modules; A plurality of power conversion modules electrically connect the corresponding energy modules to a DC bus, and a bus voltage controller, communicating with the plurality of power conversion modules; The power conversion module obtains at least one energy state parameter and a rated output value of the corresponding energy module, calculates the quotient of the energy state parameter of the corresponding energy module and the average value of the energy state parameters of the multiple energy modules, and multiplies the quotient by the rated output value to obtain the cardinality signal of each power conversion module; The bus voltage controller generates a normalized control signal based on the bus voltage of the DC bus, and transmits the control signal to each of the power conversion modules; The power conversion module obtains the control given quantity of each power conversion module according to the product of the control signal and the base signal, and adjusts the corresponding energy module according to the control given quantity.

7. The distributed power supply system according to claim 6, characterized in that: The power conversion module obtains the energy state information from the corresponding energy module at a first update frequency; The bus voltage controller transmits the control signal to each of the power conversion modules at a second update frequency, wherein the second update frequency is greater than the first update frequency.

8. The distributed power supply system according to claim 7, characterized in that: The power conversion module obtains the energy status information via digital communication at the first update frequency, and the bus voltage controller transmits the control signal to each of the power conversion modules via broadcast communication at the second update frequency.

9. The distributed power supply system according to claim 6, characterized in that: The energy status parameter is at least one of an output voltage value of the energy module, an output voltage system given value, an output current given value, a temperature detection value, a power detection value, a conversion efficiency calculation value, a charge state detection value of the energy module, and a health level detection value of the energy module; and / or The control signal is a normalized current or power value.

10. The distributed power supply system according to claim 6, characterized in that: The power conversion module is a DC / DC conversion module; and / or the energy module is a fuel cell.

11. The distributed power supply system according to claim 6, characterized in that: The DC bus is also connected to a power grid via an AC / DC conversion module.

12. The distributed power supply system according to claim 11, characterized in that: The bus voltage controller is integrated into the AC / DC conversion module, or is independently arranged outside the AC / DC conversion module.

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