A control method and device for active power distribution in a multi-machine parallel system

Abstract

The present invention relates to the field of new energy power generation control technology, and particularly relates to a control method and device for active power distribution in a multi-machine parallel system. By constructing a target control structure for the multi-machine parallel system; wherein, the multi-machine parallel system is a parallel system of multiple electrolytic hydrogen production units, and an expression of k / (1 + Ts) is introduced into the phase feedforward path of the target control structure. Then, based on the circuit topology structure of the multi-machine parallel system, the expression of the active power distributed to each electrolytic hydrogen production unit is obtained. Finally, based on the target control structure and the expression of the active power distributed to each electrolytic hydrogen production unit, an equivalent closed-loop model of the multi-machine parallel system is constructed to perform active power distribution for each electrolytic hydrogen production unit using the equivalent closed-loop model. Therefore, the above technical solution can accurately achieve active power distribution according to the rated capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy power generation control, and particularly to a control method and device for active power distribution in a multi-machine parallel system. Background Art

[0002] Hydrogen production, as an important way to achieve the goal of carbon neutrality and promote the green transformation of the energy structure, provides a stable and reliable solution for power energy demand and consumption. In an actual power system, a single power source cannot meet the actual load demand. To increase the capacity of the microgrid system and improve the power supply reliability of the system, multiple inverters are often operated in parallel. Whether the active power between multi-machine (i.e., multiple electrolytic hydrogen production units) parallel systems can be distributed according to the rated value ratio will directly affect the power supply capacity of the system.

[0003] However, the current solutions for the active power distribution problem in multi-machine parallel systems cannot accurately achieve active power distribution according to the rated capacity.

[0004] Therefore, the present invention proposes a control method and device for active power distribution in a multi-machine parallel system to solve the above technical problems. Summary of the Invention

[0005] The present invention describes a control method and device for active power distribution in a multi-machine parallel system, which can accurately achieve active power distribution according to the rated capacity.

[0006] According to a first aspect, the present invention provides a control method for active power distribution in a multi-machine parallel system, including:

[0007] Constructing a target control structure of the multi-machine parallel system; wherein, the multi-machine parallel system is a parallel system of multiple electrolytic hydrogen production units, and an expression of k / (1 + Ts) is introduced into the phase feedforward path of the target control structure;

[0008] Based on the circuit topology structure of the multi-machine parallel system, obtaining the active power expressions allocated to each electrolytic hydrogen production unit;

[0009] Based on the target control structure and the active power expressions allocated to each electrolytic hydrogen production unit, constructing an equivalent closed-loop model of the multi-machine parallel system to perform active power distribution on each electrolytic hydrogen production unit by using the equivalent closed-loop model.

[0010] According to a second aspect, a control device for active power distribution in a multi-machine parallel system includes:

[0011] A construction unit configured to construct a target control structure of the multi-machine parallel system; wherein, the multi-machine parallel system is a parallel system of multiple electrolytic hydrogen production units, and an expression of k / (1 + Ts) is introduced into the phase feedforward path of the target control structure;

[0012] A determination unit, configured to determine an active power expression allocated to each of the electrolytic hydrogen production units based on the circuit topology of the multi-machine parallel system;

[0013] An allocation unit, configured to construct an equivalent closed-loop model of the multi-machine parallel system based on the target control structure and the active power expressions allocated to each of the electrolytic hydrogen production units, so as to allocate active power to each of the electrolytic hydrogen production units by using the equivalent closed-loop model.

[0014] In a third aspect, an embodiment of the present specification further provides an electronic device, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the method described in any embodiment of the present specification is implemented.

[0015] In a fourth aspect, an embodiment of the present specification further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed on a computer, the computer is made to execute the method described in any embodiment of the present specification.

[0016] According to a control method and device for active power distribution of a multi-machine parallel system provided by the present invention, a target control structure of the multi-machine parallel system is constructed; wherein, the multi-machine parallel system is a parallel system of multiple electrolytic hydrogen production units, and an expression of k / (1 + Ts) is introduced into the phase feedforward path of the target control structure. Then, based on the circuit topology of the multi-machine parallel system, an active power expression allocated to each electrolytic hydrogen production unit is obtained. Finally, an equivalent closed-loop model of the multi-machine parallel system is constructed based on the target control structure and the active power expressions allocated to each electrolytic hydrogen production unit, so as to allocate active power to each electrolytic hydrogen production unit by using the equivalent closed-loop model. Therefore, the above technical solution can accurately achieve active power distribution according to the rated capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It shows a schematic flowchart of a control method for active power distribution of a multi-machine parallel system according to an embodiment;

[0019] Figure 2 It shows a schematic block diagram of a control device for active power distribution of a multi-machine parallel system according to an embodiment;

[0020] Figure 3Shows the circuit topology diagram of a multi-machine parallel system according to an embodiment;

[0021] Figure 4 Shows the target control structure diagram of a multi-machine parallel system according to an embodiment;

[0022] Figure 5 Shows the equivalent closed-loop model diagram before improvement according to an embodiment;

[0023] Figure 6 Shows the equivalent closed-loop model diagram according to an embodiment;

[0024] Figure 7 Shows the waveform diagram of active power distribution before improvement according to an embodiment;

[0025] Figure 8 Shows the waveform diagram of active power distribution of two parallel electrolytic hydrogen production units after improvement according to an embodiment;

[0026] Figure 9 Shows the waveform diagram of active power distribution of three parallel electrolytic hydrogen production units after improvement according to an embodiment. Detailed implementation manners

[0027] The following describes the solution provided by the present invention in conjunction with the accompanying drawings.

[0028] Figure 1 Shows a schematic flow diagram of a control method for active power distribution of a multi-machine parallel system according to an embodiment. It can be understood that this method can be executed by any device, equipment, platform, or device cluster with computing and processing capabilities. As Figure 1 shown, this method includes:

[0029] Step 100, construct the target control structure of the multi-machine parallel system; wherein, the multi-machine parallel system is a parallel system of multiple electrolytic hydrogen production units, and the expression of k / (1 + Ts) is introduced into the phase feedforward path of the target control structure;

[0030] Step 102, based on the circuit topology structure of the multi-machine parallel system, obtain the active power expression allocated to each electrolytic hydrogen production unit;

[0031] Step 104: Based on the target control structure and the active power expressions allocated to each electrolytic hydrogen production unit, construct an equivalent closed-loop model of the multi-machine parallel system to perform active power distribution on each electrolytic hydrogen production unit by using the equivalent closed-loop model.

[0032] Please refer to Figures 3 to 4, in this embodiment, the target control structure of the multi-machine parallel system is constructed; wherein, the multi-machine parallel system is a parallel system of multiple electrolytic hydrogen production units, and the expression k / (1 + Ts) is introduced into the phase feed-forward path of the target control structure. By deleting the original damping (i.e., removing the damping D in the following target control structure) to eliminate the influence of parameter coupling, and a compensation term is introduced in the phase feed-forward path to provide damping for the system. By setting appropriate k and T, sufficient damping support can be provided for the system. At the same time, there is no coupling relationship between the parameters in the compensation term and the frequency modulation coefficient. Then, based on the circuit topology structure of the multi-machine parallel system, the active power expression allocated to each electrolytic hydrogen production unit is obtained. Finally, based on the target control structure and the active power expressions allocated to each electrolytic hydrogen production unit, an equivalent closed-loop model of the multi-machine parallel system is constructed to perform active power distribution for each electrolytic hydrogen production unit using the equivalent closed-loop model. Therefore, the above technical solution can accurately achieve active power distribution according to the rated capacity.

[0033] In an embodiment of the present invention, the active power expression is:

[0034]

[0035] In the formula, i and j represent the serial numbers of the electrolytic hydrogen production units, ΔP load is the disturbance of the common load, S E is the synchronous power coefficient, ω n is the rated angular frequency, ΔP i is the active power expression allocated to the i-th electrolytic hydrogen production unit.

[0036] In some embodiments, the damping term of the target control structure is removed to eliminate the coupling relationship between the damping and the frequency modulation coefficient, and the active power loop equation is:

[0037]

[0038] Among them, P ref is the reference active power value, P e is the output active power, J is the inertia parameter, k p is the frequency modulation coefficient, ω n is the rated angular frequency.

[0039] However, this will cause the damping characteristic of the system to become weaker, and a new damping term needs to be introduced. At the same time, it is necessary to avoid the coupling between the new damping and the frequency modulation coefficient. Considering the above comprehensively, the expression k / (1 + Ts) is selected to be introduced into the phase feed-forward path, and the new active power loop equation is:

[0040]

[0041] As can be seen from the above formula, the improved target control structure can not only provide damping support for the system by setting k and T, but also decouple the damping and frequency modulation coefficients.

[0042] In an embodiment of the present invention, step 104 includes:

[0043] Based on the equivalent closed-loop model and the target control structure, the open-loop transfer function assigned to each electrolytic hydrogen production unit is obtained;

[0044] Based on the open-loop transfer function and the equivalent closed-loop model, the closed-loop transfer function assigned to each electrolytic hydrogen production unit is obtained;

[0045] Based on the closed-loop transfer function, the active power distribution of each electrolytic hydrogen production unit is obtained.

[0046] Please refer to Figure 5 , in this embodiment, by combining Figure 3 and the circuit relationship, the active power expression assigned to the i-th unit can be obtained, and the active power expression is determined by the following formula:

[0047]

[0048] where δ is the phase difference between the electrolytic hydrogen production unit and the load.

[0049] For a clearer illustration, taking two parallel units as an example, the active power expression assigned to the i-th unit is determined by the following formula:

[0050]

[0051] where i and j represent the unit numbers, here i = 1, j = 2 or i = 2, j = 1, ΔP load is the disturbance of the common load, and based on this, the equivalent closed-loop model diagram before improvement is established, as Figure 5 shown.

[0052] For a two-parallel system, the open-loop transfer function between its output phase and the distributed power is determined by the following formula:

[0053]

[0054] where D is the damping, and then the closed-loop transfer function is derived respectively. The closed-loop transfer function is determined by the following formula:

[0055]

[0056] where ΔP VSG,i is the small disturbance component of the output power of each unit.

[0057] Furthermore, the active power distribution of each electrolytic hydrogen production unit is:

[0058]

[0059] According to the above formula, it can be seen that if the active power distribution among the parallel units is to satisfy k P1 / k P2 = 1:2, then D 1 / D 2 = 1:2, and it can be seen from the above formula that the active power sharing ratio depends on both the frequency modulation coefficient and the damping at the same time. When k p1 :k p2 = 1:2, the changes in D 1 and D 2 will have a significant impact on the power distribution, indicating that the multi-machine parallel system cannot distribute active power in proportion to the rated capacity due to the existence of damping.

[0060] Please refer to Figure 6 , in an embodiment of the present invention, the open-loop transfer function is:

[0061]

[0062] In the formula, J is the inertia parameter, k i is the amplification coefficient of the i-th electrolytic hydrogen production unit, T i is the time constant of the i-th electrolytic hydrogen production unit, and s is a complex variable.

[0063] In an embodiment of the present invention, the closed-loop transfer function is:

[0064]

[0065] In the formula, ΔP E_VSG,i is the small disturbance component of the output power of each unit.

[0066] In an embodiment of the present invention, the active power distribution is:

[0067]

[0068] In the formula, k p is the frequency modulation coefficient.

[0069] In this embodiment, the active power distribution is only related to the ratio of the frequency modulation coefficients and has nothing to do with other parameters, achieving the goal of distributing active power in proportion to the rated capacity in the multi-machine parallel system.

[0070] As Figure 7 shown, in some embodiments, the output powers of two parallel units P 1 are adjusted from 10 kW to 20 kW, and P 2 is adjusted from 16 kW to 26 kW. In the system before improvement, P 1 and P 2It is allocated proportionally, while in Figure 8 for two units, P 1 and P 2 are both allocated according to the frequency modulation coefficient of 1:2 to obtain the allocated power. Similarly, in Figure 9 for three units, they are all allocated according to the frequency modulation coefficient of 1:2:3 to obtain the allocated power.

[0071] From the waveform diagram of the active power distribution before improvement, it can be clearly seen that the allocated power of the two electrolytic hydrogen production units cannot accurately achieve the active power distribution according to the rated capacity. The existence of damping makes it often impossible for the multi-machine parallel system to accurately distribute the active power according to the rated capacity. Whether the active power distribution between the multi-machine parallel systems can be distributed according to the rated value ratio will directly affect the power supply capacity of the system, while the improved multi-machine parallel system has well solved this problem.

[0072] According to an embodiment on the other hand, the present invention provides a control device for active power distribution of a multi-machine parallel system. Figure 2 The schematic block diagram of a control device for active power distribution of a multi-machine parallel system according to an embodiment is shown. It can be understood that this device can be implemented by any device, equipment, platform, and equipment cluster with computing and processing capabilities. As Figure 2 shown, this device includes: a construction unit 200, a determination unit 202, and an allocation unit 204. The main functions of each component unit are as follows:

[0073] The construction unit 200 is configured to construct the target control structure of the multi-machine parallel system; wherein, the multi-machine parallel system is a parallel system of multiple electrolytic hydrogen production units, and the expression of k / (1 + Ts) is introduced into the phase feedforward path of the target control structure;

[0074] The determination unit 202 is configured to determine the active power expression allocated to each electrolytic hydrogen production unit based on the circuit topology structure of the multi-machine parallel system;

[0075] The allocation unit 204 is configured to construct an equivalent closed-loop model of the multi-machine parallel system based on the target control structure and the active power expressions allocated to each electrolytic hydrogen production unit, so as to use the equivalent closed-loop model to allocate the active power of each electrolytic hydrogen production unit.

[0076] As a preferred implementation manner, the active power expression is:

[0077]

[0078] In the formula, i and j represent the serial numbers of the electrolytic hydrogen production units, ΔP load is the disturbance of the common load, S E is the synchronous power coefficient, ω n is the rated angular frequency, ΔP iThe active power expression allocated to the i-th electrolytic hydrogen production unit.

[0079] As a preferred embodiment, the open-loop transfer function is:

[0080]

[0081] In the formula, J is the inertia parameter, k i is the amplification coefficient of the i-th electrolytic hydrogen production unit, T i is the time constant of the i-th electrolytic hydrogen production unit, and s is a complex variable.

[0082] As a preferred embodiment, the closed-loop transfer function is:

[0083]

[0084] In the formula, ΔP E_VSG,i is the small disturbance component of the output power of each unit.

[0085] As a preferred embodiment, the active power distribution is:

[0086]

[0087] In the formula, k p is the frequency modulation coefficient.

[0088] Among them, the distribution unit 204 can be specifically configured as:

[0089] Based on the equivalent closed-loop model and the target control structure, determine the open-loop transfer function allocated to each electrolytic hydrogen production unit;

[0090] Based on the open-loop transfer function and the equivalent closed-loop model, determine the closed-loop transfer function allocated to each electrolytic hydrogen production unit;

[0091] Based on the closed-loop transfer function, obtain the active power distribution of each electrolytic hydrogen production unit.

[0092] According to an embodiment of another aspect, there is also provided a computer-readable storage medium, on which a computer program is stored. When the computer program is executed in a computer, the computer is made to execute the method described in combination with Figure 1 the above.

[0093] According to an embodiment of still another aspect, there is also provided an electronic device, including a memory and a processor. An executable code is stored in the memory. When the processor executes the executable code, the method described in combination with Figure 1 the above is implemented.

[0094] Each embodiment in the present invention is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the apparatus embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, reference can be made to the corresponding descriptions in the method embodiments.

[0095] Those skilled in the art should be able to realize that in one or more of the above examples, the functions described in the present invention can be implemented by hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium.

[0096] The above specific implementation manners further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific implementation manners of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solution of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control method for active power distribution of a multi-machine parallel system, characterized in that: include: Constructing a target control structure of a multi-machine parallel system; wherein the multi-machine parallel system is a parallel system of multiple electrolysis hydrogen production units, and introducing an expression of k / (1+Ts) in a phase feedforward path of the target control structure; Based on the circuit topology of the multi-machine parallel system, an expression for the active power allocated to each of the electrolytic hydrogen production units is obtained; Based on the target control structure and the active power expression allocated to each of the electrolytic hydrogen production units, an equivalent closed-loop model of the multi-machine parallel system is constructed to allocate active power to each of the electrolytic hydrogen production units using the equivalent closed-loop model; The active power expression is determined by the following formula: In the formula, i and j represent the serial number of the electrolytic hydrogen production unit, ΔP load is the disturbance of the public load, S E is the synchronous power coefficient, Δδ is the phase difference between the electrolytic hydrogen production unit and the load, ω n is the rated angular frequency, ΔP i The expression of active power allocated to the i-th electrolysis hydrogen production unit; The method of using the equivalent closed-loop model to distribute active power to each of the electrolysis hydrogen production units includes: Based on the equivalent closed-loop model and the target control structure, an open-loop transfer function allocated to each of the electrolytic hydrogen production units is obtained; Based on the open-loop transfer function and the equivalent closed-loop model, a closed-loop transfer function allocated to each of the electrolytic hydrogen production units is obtained; Based on the closed-loop transfer function, obtaining the active power distribution of each of the electrolysis hydrogen production units; The open loop transfer function is determined by the following formula: Where J is the inertia parameter, k i is the gain factor of the i-th electrolytic hydrogen production unit, T i is the time constant of the i-th electrolytic hydrogen production unit, and s is a complex variable; The closed-loop transfer function is determined by the following formula: The active power distribution is determined by the following formula: In the formula, ΔP E_VSG,i is the small disturbance component of the output power of each unit, k p is the frequency modulation coefficient.

2. A control device for active power distribution of a multi-machine parallel system, characterized in that: include: A construction unit is configured to construct a target control structure of a multi-machine parallel system; wherein the multi-machine parallel system is a parallel system of multiple electrolysis hydrogen production units, and an expression of k / (1+Ts) is introduced in a phase feedforward path of the target control structure; A determination unit is configured to determine an expression for the active power allocated to each of the electrolysis hydrogen production units based on a circuit topology of the multi-machine parallel system; A distribution unit is configured to construct an equivalent closed-loop model of the multi-machine parallel system based on the target control structure and the active power expression allocated to each of the electrolytic hydrogen production units, so as to allocate active power to each of the electrolytic hydrogen production units using the equivalent closed-loop model; The allocation unit is specifically configured as follows: Based on the equivalent closed-loop model, determining the open-loop transfer function assigned to each of the electrolysis hydrogen production units; Determining the closed-loop transfer function assigned to each of the electrolytic hydrogen production units based on the open-loop transfer function and the equivalent closed-loop model; Based on the closed-loop transfer function, allocating active power distribution of each of the electrolytic hydrogen production units; The active power expression is determined by the following formula: In the formula, i and j represent the serial number of the electrolytic hydrogen production unit, ΔP load is the disturbance of the public load, S E is the synchronous power coefficient, Δδ is the phase difference between the electrolytic hydrogen production unit and the load, ω n is the rated angular frequency, ΔP i The expression of active power allocated to the i-th electrolysis hydrogen production unit; The open loop transfer function is determined by the following formula: Where J is the inertia parameter, k i is the gain factor of the i-th electrolytic hydrogen production unit, T i is the time constant of the i-th electrolytic hydrogen production unit, and s is a complex variable; The closed-loop transfer function is determined by the following formula: The active power distribution is determined by the following formula: In the formula, ΔP E_VSG,i is the small disturbance component of the output power of each unit, k p is the frequency modulation coefficient.

3. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method according to claim 1 is implemented.

4. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed in a computer, the computer is caused to execute the method of claim 1.

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