Test system for power unit of energy storage system

Abstract

The utility model provides a test system for a power unit of an energy storage system, the test system comprises a main control module and a module to be tested, and the module to be tested comprises at least one power unit to be tested, a current sampling unit and a load reactor; the main control module is connected with the to-be-tested module; and the main control module receives current parameters obtained by sampling the load loop by the current sampling unit, and adjusts the modulation degree in a load switching mode according to the current parameters so as to adapt to different test environments. According to the exemplary embodiment, the testing flexibility is enhanced, and the testing efficiency of the power unit is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of energy storage, and particularly relates to a test system of a power unit of an energy storage system. BACKGROUND

[0002] The high-voltage cascaded energy storage system has large single-machine capacity and high system integration degree, and the number of cascaded units increases with the increase of capacity. Defects of products constituting the energy storage system will affect the stable operation of the entire energy storage system. Therefore, before formal completion, the conditions of the products in the actual use process need to be simulated, and the products need to be tested in the simulated environment.

[0003] In the related art, the test system of the power unit of the energy storage system usually tests the communication performance of the product, and the power units are tested one by one in the test process.

[0004] It should be noted that the statements herein only provide background information related to the present disclosure, and do not necessarily constitute the prior art. CONTENT OF THE INVENTION

[0005] In view of the above problems, a test system of a power unit of an energy storage system is proposed to overcome the above problems or at least partially solve the above problems.

[0006] The embodiments of the present disclosure adopt the following technical solutions:

[0007] In a first aspect, a test system of a power unit of an energy storage system is provided, the test system comprising: a master control module and a to-be-tested module, the to-be-tested module comprising at least one to-be-tested power unit, a current sampling unit, and a load reactor; the master control module is connected with the to-be-tested module; the master control module receives current parameters obtained by the current sampling unit sampling a load loop, and adjusts a regulation degree by load switching according to the current parameters to adapt to different test environments.

[0008] Preferably, the load reactor comprises a plurality of parallel reactors. The master control module comprises a master controller. The to-be-tested power unit comprises a plurality of to-be-tested power units, and the plurality of to-be-tested power units are cascaded in the to-be-tested module.

[0009] Preferably, the test system further comprises a power supply module, the power supply module comprising a voltage regulator, a transformer, and at least one rectifier bridge unit, an input end of the voltage regulator being connected with an alternating current power supply, an output end of the voltage regulator being connected with the transformer; an output end of the transformer is connected with the to-be-tested module through the rectifier bridge unit.

[0010] Preferably, the rectifier bridge unit comprises a plurality of rectifier bridge units connected in parallel to the power supply module; the output of the transformer is connected to each cascaded power unit to be tested through the plurality of parallel rectifier bridge units.

[0011] Preferably, the test system further comprises a liquid cooling module connected to the main control module. The current sampling unit comprises a Hall current sensor.

[0012] The above at least one technical solution adopted by the exemplary embodiments can achieve the following beneficial effects:

[0013] The exemplary embodiments of the present disclosure can batch test the power units for function and aging by the interaction between the main controller and the modules to be tested, and can make the power units to be tested run in a similar field working condition, realize long-time simulation running, and achieve the aging effect.

[0014] It should be understood that the present disclosure is not intended to identify key or essential features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of some embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which:

[0016] Figure 1 A schematic diagram of a test system for a power unit of an energy storage system in an embodiment of the present disclosure;

[0017] Figure 2 A connection diagram of a test system for a power unit of an energy storage system in an embodiment of the present disclosure;

[0018] Figure 3 A control strategy block diagram of a test system for a power unit of an energy storage system in an embodiment of the present disclosure;

[0019] Figure 4 A small current function test flowchart in an embodiment of the present disclosure;

[0020] Figure 5 A large current aging test flowchart in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0021] The principles of the present disclosure will now be described with reference to some embodiments. It should be understood that the description of these embodiments is merely intended to be illustrative and to assist in understanding and implementing the present disclosure, and does not in any way limit the scope of the present disclosure. The disclosure described herein can be implemented in a manner different from that described below.

[0022] In the following description and claims, unless otherwise defined, all 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 belongs.

[0023] Reference throughout this disclosure to "one embodiment", "an embodiment", "exemplary embodiment", or similar terms means that a described embodiment can include a particular feature, structure, or characteristic, but every embodiment can not necessarily include the particular feature, structure, or characteristic. Moreover, these terms do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is submitted that it is within the knowledge of those skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0024] It should be understood that although the terms "first" and "second" etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of example embodiments. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed terms.

[0025] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "including", "having" and / or "contains" as used herein, specifies the presence of stated features, elements and / or components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0026] As used in this disclosure, the term "circuitry" can refer to one or more or all of the following:

[0027] (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and

[0028] (b) combinations of hardware circuits and software, such as (as applicable):

[0029] (i) combinations of analog and / or digital hardware circuits with software / firmware and

[0030] (ii) any portions of hardware processor(s) with software (including digital signal processors); and

[0031] (c) hardware circuitry and / or a processor, e.g., a microprocessor(s) or a portion of microprocessor(s), that requires software (e.g., firmware) for operation, but need not necessarily have software (e.g., firmware) present.

[0032] This definition of circuitry applies to all uses of this term in this disclosure, including in any claims. As a further example, as used in this disclosure, the term circuitry also includes implementations having only hardware circuitry or only processor(s) (e.g., or portions of processor(s)) with accompanying software and / or firmware. The term circuitry also includes, for example, a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

[0033] The high-voltage cascaded energy storage system realizes direct connection to the high-voltage power grid without a step-up transformer by adopting a cascaded topology and a control algorithm, and each phase is shifted and superimposed by a plurality of H-bridge energy storage converter units in series. The single-machine power of the system is greatly improved compared with the traditional low-voltage scheme, and the single-machine rated output power ranges from 10 MW to 30 MW, which is particularly suitable for high-voltage large-capacity energy storage applications such as grid-side energy storage peak shaving and frequency modulation power stations, combined AGC frequency modulation of thermal power units, and increasing penetration of new energy power stations.

[0034] The high-voltage cascaded energy storage system has a large number of cascaded power units, and each unit needs to be tested and aged before formal completion, thereby reducing the system failure rate. The applicant has researched related technologies, and found that the current testing methods for the power units of the high-voltage cascaded system include the following.

[0035] One scheme is to only perform function verification, and by simulating the control signals of the main controller, the power unit performs corresponding input and output, which can fully verify the wiring problems and logic problems of the unit.

[0036] The second scheme is to build a small-current unit detection platform, and the power unit actually communicates with the main controller through optical fiber, and the system executes normal standby, operation, shutdown and other logic.

[0037] The above two schemes have the following problems in actual application:

[0038] The first method cannot truly communicate with the main controller, and cannot run current, so the detection capability is limited, and it is only used as a preliminary pre-detection test.

[0039] In the second mode, the power unit capacitor has a certain DC voltage, and can run a small current, but cannot perform large current test aging test, which has a large gap with the actual working condition. In addition, the small current function test system uses one source, one load and one controller to test only one power unit, which is very low in efficiency.

[0040] In the example embodiment, in view of the low efficiency and incomplete test of the power unit of the energy storage system in the related art, a universal test system for the power unit of the energy storage system is designed. The test system can perform function and aging test on the power unit in batches through the interaction and adjustment of the main control module and the test module, can make the power unit to be tested run in a working condition similar to the field, realize long-time simulation running, and achieve the aging effect.

[0041] The technical solutions provided by the embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0042] The disclosure embodiment provides a test system for a power unit of an energy storage system. As shown in Figure 1 The test system 100 of the disclosure embodiment includes a main control module 110 and a test module 120. The test module 120 includes at least one power unit 1203 to be tested, a current sampling unit 1201, and a load reactor 1202. The main control module 110 includes a main controller 1101. The main control module is connected to the test module. The main control module receives current parameters obtained by sampling a load loop by the current sampling unit, and adjusts the modulation degree by load switching according to the current parameters, so as to adapt to different test environments.

[0043] In one example, as shown in Figure 2 The test system further includes a power supply module. The power supply module includes a voltage regulator, a (multi-winding) transformer, and at least one rectifier bridge unit. The input end of the voltage regulator is connected to an AC power supply, and the output end of the voltage regulator is connected to the transformer. The output end of the transformer is connected to the test power unit through the rectifier bridge unit. The test module includes a plurality of power units to be tested, such as power unit A1, power unit A2, and power unit A3 as shown in Figure 2 According to the test needs, a plurality of power units can be connected in parallel for simultaneous test.

[0044] Continuing to refer to Figure 2When the to-be-tested module includes multiple to-be-tested power units, the output end of the transformer is connected with multiple parallel rectifier bridge units, and each rectifier bridge unit is connected with one to-be-tested power unit. The load reactor is connected in the load circuit. The load reactor includes multiple parallel reactors, each of which has the same rated current and the same inductance value, and the multiple reactors are combined in different ways to realize adjustment of different modulation degrees in response to the load switching by the master control module. The current sampling unit includes a Hall current sensor for collecting the load circuit current.

[0045] In some embodiments, the master control module includes a master controller that communicates with the to-be-tested power units through an optical fiber cable. The master control module is further configured to process the modulation degree in a first manner when the sampled load current parameter is less than a, in a second manner when the sampled load current parameter is greater than b, and in a third manner when the sampled load current parameter is greater than a and less than b, where a and b are integers.

[0046] Reference Figure 2 , Figure 3 The DC side power supply of the to-be-tested power unit is a multi-winding (isolating) transformer that obtains the DC voltage U dc of the simulated battery cluster through a three-phase uncontrolled rectifier bridge.

[0047] The load side of the test system is a Hall current sampling and load reactor L. In one example, the power unit and the load are required to operate at the rated current, so liquid cooling (equipment) is added. The to-be-tested power units A1-A3 are cascaded, and can be expanded to multiple cascaded units according to test requirements.

[0048] It can be understood that in actual tests, single, two, and three combination tests can be performed according to different test conditions, and the test system has high flexibility.

[0049] The master controller communicates with the power unit and the liquid cooling module in real time through an optical fiber, has the functions of state input, emergency stop button input, load over-temperature input, and simultaneously outputs the running state. The Hall element samples the load current.

[0050] In one example, the DC side voltage is U dc , the inductance value of the AC side load reactor is L, and the rated current is I N , and the modulation degree of a single to-be-tested power unit under full load aging operation is Since too small modulation degree can easily lead to large current fluctuation and unstable control, the inductance value of the reactor L needs to be relatively large.

[0051] In another example, assuming the load reactor rated current I N = 600A, the DC side voltage U dc = 1000V, the load reactor is selected as L = 2.5mH, then m N = 0.471, the three units full load operating modulation degree is m N3 = 0.157.

[0052] The test system of the present disclosure can perform a small current function test and a large current test aging test, wherein the small current function test is a basic function test of a single unit, and the large current test aging test is a simultaneous test of multiple to-be-tested power units, i.e., a full load test. When performing the small current function test, the test power unit A1 is only closed K1, and the others are similar, which will not be described here.

[0053] In one example, when performing the small current function test, the small current effective value is I0= 30A, and if the aging test current parameter is run, the modulation degree is m0= 0.02355 at this time. At this time, the modulation degree is too low, and the modulation degree can be adjusted by adjusting the load reactor.

[0054] In one example, the total inductance value of the load reactor is 2.5mH, which is composed of multiple reactors in parallel to form a load that can be switched, thereby ensuring that the modulation degree is a suitable value. For example, 10 60A 25mH reactors can be connected in parallel to obtain this way, so that the modulation degree adjustment can be realized by switching. The small current function test input reactor is a 60A 10mH reactor, and the modulation degree can reach m1= 0.2355 at this time, and the operating condition is improved. The large current test aging test is calculated according to multiple 60A 10mH reactors used at the same time.

[0055] In some embodiments, the sampling load current parameter at least includes a Hall current, and the master control module is further configured to integrate and accumulate the modulation degree with a first step size when the Hall current is less than N times a given current value; integrate and accumulate the modulation degree with a second step size when the Hall current is greater than M times the given current value; and fine-tune the modulation degree using a PI controller when the Hall current is within the N-M times interval of the given current value.

[0056] Reference Figure 3 When the Hall current is less than a first preset value, such as 0.95 times the given current value, the modulation degree is integrated and accumulated with a certain step size m_Step: m_Step = K i *Ts; wherein Ki is an integral coefficient, and Ts is a sampling time.

[0057] When the Hall current is greater than the second preset value, such as 1.05 times the given current value, the modulation degree is integrated and accumulated in a certain step m_Step: m_Step = -K i *Ts; wherein, K1 is the integral coefficient, and Ts is the sampling time.

[0058] When the Hall current is between the first preset value and the second preset value, such as 0.95-1.05 times the given current value, a PI controller is used to fine-tune the modulation degree, so that the test system works stably. Wherein, m_Step is the modulation degree step, K1 is the integral coefficient, and Ts is the sampling time.

[0059] In some embodiments, the main controller circuit communicates with the power unit to be tested in real time through an optical fiber, so as to set a first given current, execute a start-up logic control strategy, and start software and hardware protection when performing a small current function test; set a second given current, execute a start-up logic control strategy of multiple power units to be tested, and start software and hardware protection when performing a large current aging test. When performing the test, the method comprises: powering on the test system; starting the power unit to be tested according to the given current value; receiving the sampling load current parameters obtained by sampling the load reactor by the current sampling module; and adjusting the different modulation degrees by switching to adapt to different test environments according to the sampling load current parameters.

[0060] In order to better illustrate the small current function test in the present application, reference is made to Figure 4 The small current function test process is as follows:

[0061] According to the power unit to be tested, once wiring is performed, a large impedance load is selected by switching to improve the control effect.

[0062] The human-computer interaction interface controls the main controller to enter the small current function test mode of the corresponding unit, sets the running parameters, including the given current value, the rated current value, the DC over-voltage and under-voltage protection value, etc., wherein the running rated current is set to 100A.

[0063] Click "Standby" to execute the single power unit soft start process, and judge whether the contactor action of the power unit to be tested in the DC soft start process is normal. If not, set the unit state to "fault".

[0064] After the standby is successful, the given current value is set to 30A, and "Start" is clicked. The test system executes the start-up logic control strategy, and simultaneously executes the software and hardware protection.

[0065] If a fault occurs in normal operation, the state of the power unit to be tested is set to "fault".

[0066] After normal operation, standby is performed, discharge operation is performed, and the unit state is set to "normal".

[0067] It can be understood that the small current function test tests the power unit in terms of basic function logic on one hand, and prepares for the subsequent unit aging test through the set unit state on the other hand.

[0068] Reference Figure 5 The large current aging test process is as follows:

[0069] The power unit in the small current function test with the unit state "normal" is connected once for aging test. The power unit for aging test can be 1, 2, 3…Y units, and is put into full load impedance.

[0070] The main controller is controlled to enter the large current test aging test mode through the man-machine interface, and the operating parameters are set, including the given current value, the rated current value, the DC overvoltage and undervoltage protection value, etc., wherein the operating rated current is set to 600A.

[0071] After standby is clicked, the soft start process of multiple power units is performed, and it is judged whether the contactor of the power unit in the "normal state" during the DC soft start process is normal. The unit in the "fault state" is not executed for standby action, and no fault judgment is made.

[0072] After standby is successful, the given current value 600A is set, and "start" is clicked, so that the test system executes the start logic control strategy of multiple power units, and simultaneously executes the software and hardware protection.

[0073] When the aging specified rated current operation duration is completed, the given current value is gradually reduced to 30A.

[0074] The standby is turned, the discharge operation is performed, and the large current aging test is completed.

[0075] It can be understood that the test system in the present disclosure can configure multiple series of power units, is easy to expand, the current control strategy of the power unit has good working condition adaptability, can smoothly realize the transition from the small current function test to the large current aging test, and improves the test efficiency. Secondly, the test platform can perform function test on the power unit in small current, can also adapt to different series of power units for large current test and aging test, can configure the power unit type through parameters, can also simulate the battery cluster under different voltage levels through the voltage regulator, improves the power unit test efficiency, improves the hardware resource utilization rate, and guarantees the product quality.

[0076] It should be noted that, in the description of the present application, the terms "first", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance. In addition, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified and limited.

[0077] In the present application, unless specifically defined and limited otherwise, the terms "mount", "connect", "connection", "fixed", and the like, should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection or communication with each other; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0078] In the present application, unless specifically defined and limited otherwise, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0079] Any process or method descriptions in flow charts or otherwise described herein can be understood as representing code modules, segments, or portions of code that include one or more executable instructions for implementing specific logic functions or other processes, and the various embodiments of the present application include additional implementations in which the functions described with reference to the figures are implemented in different orders, in different ways, or with different structures, as will occur to those skilled in the art. The scope of the present application is not limited to the described embodiments.

[0080] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0081] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that changes, modifications, substitutions and variations can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A test system for a power unit of an energy storage system, characterized by, The test system comprises a master control module and a module to be tested, the module to be tested comprising at least one power unit to be tested, a current sampling unit and a load reactor; the master control module is connected with the module to be tested. The master control module is configured to receive current parameters obtained by the current sampling unit sampling a load loop, and adjust a regulation degree by load switching according to the current parameters, so as to adapt to different test environments.

2. The test system of claim 1, wherein, The load reactor comprises a plurality of parallel reactors.

3. The test system of claim 2, wherein, The master control module comprises a master controller.

4. The test system of claim 3, wherein, The module to be tested comprises a plurality of power units to be tested, and the plurality of power units to be tested are cascaded in the module to be tested.

5. The test system of any of claims 1-4, wherein, The test system further comprises a power supply module, the power supply module comprising a voltage regulator, a transformer and at least one rectifier bridge unit; an input end of the voltage regulator is connected with an alternating current power supply, an output end of the voltage regulator is connected with the transformer; an output end of the transformer is connected with the module to be tested through the rectifier bridge unit.

6. The test system of claim 5, wherein, The rectifier bridge unit comprises a plurality of rectifier bridge units, and the plurality of rectifier bridge units are connected in parallel in the power supply module.

7. The test system of claim 6, wherein, The output end of the transformer is connected with each cascaded power unit to be tested through a plurality of parallel rectifier bridge units.

8. The test system of claim 3, wherein, The test system further comprises a liquid cooling module, and the liquid cooling module is connected with the master controller.

9. The test system of claim 7, wherein, The current sampling unit comprises a Hall current sensor.

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