Secondary control method of P / V energy storage converter based on PI consistency

Abstract

The invention provides a PI consistency-based secondary control method for a P / V energy storage converter, and the method comprises the steps: generating an output signal of a secondary controller through a PI consistency algorithm according to the power state variables of each distributed power supply and all distributed power supplies communicating with the distributed power supply; compensating and correcting the P / V droop control equation based on the output signal to obtain a voltage reference value and an angular frequency reference value; based on the voltage reference value, a modulation signal is obtained through an internal control loop; and on the basis of the modulation signal and the angular frequency reference value, through Park transformation and SPWM modulation, an on-off control signal of an inverter switching tube is obtained, and distributed secondary control of the converter is completed. By adopting the secondary control method based on the PI consistency algorithm, the active power sharing among the distributed energy storage units and the recovery of the voltage and the frequency of the power distribution network can be realized, and the power sharing error caused by the line impedance is eliminated.

Description

Technical Field

[0001] The present application relates to the field of electrical engineering technology, and in particular to a secondary control method of a P / V energy storage converter based on PI consistency and a secondary control device of a P / V energy storage converter based on PI consistency. Background Art

[0002] Distributed energy storage has been widely used in the field of renewable energy. Reasonable power allocation between energy storage units helps to improve energy utilization and economic benefits, while avoiding converter overload and overshoot and overdischarge of energy storage units. Hierarchical control strategies are usually used to achieve the desired power sharing between distributed energy storage units.

[0003] The lower-level control in the hierarchical control strategy is generally droop control. In the traditional P / fQ / V droop control, due to the dispersed distribution of distributed energy storage units in the low-voltage distribution network, the line impedance from each distributed energy storage unit to the grid connection point PCC is inconsistent, and the line resistance is much larger than the reactance, resulting in the reactive power between the parallel distributed energy storage units cannot be proportionally distributed according to the droop coefficient, and the droop control accuracy is low. At the same time, if P / VQ / f droop control is adopted, the problem of inaccurate active power sharing ratio will also occur.

[0004] Therefore, it is usually necessary to introduce secondary control to achieve balanced power distribution among distributed energy storage units. The upper-level control of hierarchical control is distributed secondary control, which is used to improve the accuracy and performance of control. It does not rely on the central controller, but achieves the control target through the collaboration of multiple local controllers, and has stronger robustness. However, for distributed control, if any distributed energy storage unit exchanges information with all other distributed energy storage units, when there are many distributed energy storage units, the communication topology is very complex, which will increase the communication cost and the probability of communication failure. By introducing a consistency algorithm, distributed energy storage units can communicate only with adjacent distributed energy storage units, which greatly increases the sparsity of the communication network. However, distributed control based on a consistent algorithm will inevitably be affected by communication delays and the initial value of the integrator, resulting in control deviations. Summary of the invention

[0005] The main purpose of the present application is to provide a secondary control method of a P / V energy storage converter based on PI consistency and a secondary control device of a P / V energy storage converter based on PI consistency, so as to at least solve the problem of control deviation in the prior art of distributed control in a low-voltage resistance power grid, which leads to uneven power distribution.

[0006] According to one aspect of the present application, a secondary control method of a P / V energy storage converter based on PI consistency is provided, and the method includes the following steps: S1, generating an output signal of a secondary controller through a PI consistency algorithm according to the power state variables of each distributed power source and all distributed power sources communicating with it; S2, based on the output signal, compensating and modifying the P / V droop control equation to obtain a voltage reference value and an angular frequency reference value; S3, based on the voltage reference value, obtaining a modulation signal through an internal control loop; S4, based on the modulation signal and the angular frequency reference value, obtaining an inverter switch on / off control signal through Park transformation and SPWM modulation, thereby completing the distributed secondary control of the converter.

[0007] Optionally, S1 includes: S1.1, according to the power state variables and P / V control droop coefficients of each distributed power source and all distributed power sources communicating with it, obtaining an additional variable ζ introduced by the PI consistency algorithm vi and ωi ; S1.2, based on additional variable ζ ωi The reactive power state variables of all distributed power sources that each distributed power source communicates with are used to obtain the reactive compensation correction value output by the secondary controller, thereby realizing the secondary control of the consistent frequency. vi The voltage compensation correction is obtained by calculating the active power state variables of all distributed power sources that each distributed power source communicates with. By setting the minimum deviation between the bus voltage and the voltage rating as the objective function, the active compensation signal output by the secondary controller is calculated, thereby realizing secondary control of the consistent voltage.

[0008] Optionally, S1.1 includes: calculating the deviation between the power distribution adjustment correction amount of each converter and the power distribution adjustment correction amount of all converters communicating with it according to the power state variables and the P / V control droop coefficient of each distributed power source and all distributed power sources communicating with it, and performing weighted summation to obtain the additional variables introduced by the PI consistency algorithm.

[0009] Optionally, the S1.2 includes: based on the additional variable ζ ωi The reactive power state variables of all distributed power sources that each distributed power source communicates with are used to obtain the reactive compensation correction value output by the secondary controller according to the consistency algorithm model, thereby realizing the secondary control of the consistency frequency. vi The active power state variables of all distributed power sources that each distributed power source communicates with are calculated according to the consistency algorithm model, and the active power compensation signal output by the secondary controller is obtained by setting the minimum deviation between the bus voltage and the voltage rating as the objective function, thereby realizing secondary control of the consistency voltage.

[0010] Optionally, S2 includes: introducing P / V droop control as an adjustment correction amount according to the active and reactive compensation signals output by the secondary controller to obtain a voltage reference value and an angular frequency reference value of an internal control loop.

[0011] Optionally, S3 includes: S3.1, based on the difference between the voltage reference value and the sampling value of the output voltage, obtaining the inverter output inductor current reference value through PI control of the voltage loop; S3.2, based on the difference between the inductor current reference value and the sampling value of the inductor current, obtaining the modulation signal through PI control of the current loop.

[0012] Optionally, the S3.1 includes: obtaining the inverter output inductor current reference value through PI control based on the sum of the reference voltage and the power distribution adjustment correction amount of each power supply minus the output voltage of the distributed power supply.

[0013] Optionally, the S3.2 includes: obtaining an output voltage instruction of the distributed power supply through PI control based on a current reference value and an inductor current sampling value.

[0014] Optionally, the S4 includes: obtaining a modulation signal through Park transformation based on the modulation signal and the angular frequency reference value, and obtaining a switching control signal of the switch tube through SPWM modulation.

[0015] According to another aspect of the present application, a secondary control device of a P / V energy storage converter based on PI consistency is provided, and the device includes: a generating unit, which is used to generate an output signal of a secondary controller according to the power state variables of each distributed power source and all distributed power sources communicating with it through a PI consistency algorithm; a compensation unit, which is used to compensate and modify the P / V droop control equation based on the output signal to obtain a voltage reference value and an angular frequency reference value; a first processing unit, which is used to obtain a modulation signal through an internal control loop based on the voltage reference value; and a second processing unit, which is used to obtain an inverter switch on / off control signal through Park transformation and SPWM modulation based on the modulation signal and the angular frequency reference value, so as to complete the distributed secondary control of the converter.

[0016] By applying the technical solution of the present application, the output signal of the secondary controller is generated through the PI consistency algorithm according to the power state variables of each distributed power source and all distributed power sources communicating with it. Based on the output signal, the P / V droop control equation is compensated and modified to obtain the voltage reference value and the angular frequency reference value. Based on the voltage reference value, a modulation signal is obtained through an internal control loop. Based on the modulation signal and the angular frequency reference value, the switching control signal of the inverter switch tube is obtained through Parker transformation and SPWM modulation to complete the distributed secondary control of the converter. Through the PI consistency algorithm, a power compensation signal is generated, which eliminates the uneven power distribution caused by the inconsistent line impedance from each distributed energy storage unit to the grid connection point PCC, adjusts the output power of each distributed energy storage unit, and effectively shortens the time required for control, avoids the communication delay problem, and effectively realizes power sharing and voltage and frequency recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 A hardware structure block diagram of a mobile terminal for executing a secondary control method of a P / V energy storage converter based on PI consistency provided in an embodiment of the present application is shown;

[0019] Figure 2 A schematic flow chart of a secondary control method of a P / V energy storage converter based on PI consistency according to an embodiment of the present application is shown;

[0020] Figure 3 is a schematic diagram of a low voltage power system topology provided in an embodiment;

[0021] Figure 4 Schematic diagram of distributed P / V droop control principle provided by an embodiment of the present invention;

[0022] Figure 5 (a) is the output voltage waveform curve of the system with secondary control. Figure 5 (b) is the output active power waveform curve of the system with secondary control. Figure 5 (c) Output frequency waveform of the system with secondary control, Figure 5 (d) is the output reactive power waveform curve of the system with secondary control;

[0023] Figure 6 (a) is the output voltage waveform curve of the system without secondary control. Figure 6 (b) is the output active power waveform curve of the system without secondary control. Figure 6 (c) Output frequency waveform of the system without secondary control, Figure 6 (d) is the output reactive power waveform curve of the system without secondary control;

[0024] Figure 7 (a) is the voltage compensation signal curve generated by the PI consistency algorithm. Figure 7 (b) Frequency compensation signal curve generated by PI consistency algorithm;

[0025] Figure 8 (a) is the voltage curve of each distributed power supply output under the communication delay of 0.1s. Figure 8 (b) is the active power curve of each distributed power source output under the communication delay of 0.1s. Figure 8 (c) is the frequency curve of each distributed power output of the system under a communication delay of 0.1s;

[0026] Fig. 9 A structural block diagram of a secondary control device of a P / V energy storage converter based on PI consistency provided according to an embodiment of the present application is shown.

[0027] The above drawings include the following reference numerals:

[0028] 102, processor; 104, memory; 106, transmission device; 108, input and output devices. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] As introduced in the background technology, in the prior art, distributed control has control deviations in low-voltage resistance power grids, which leads to uneven power distribution. To solve the above problems, an embodiment of the present application provides a secondary control method of a P / V energy storage inverter based on PI consistency and a secondary control device of a P / V energy storage inverter based on PI consistency.

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0034] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 1 1 is a hardware structure block diagram of a mobile terminal of a secondary control method of a P / V energy storage converter based on PI consistency according to an embodiment of the present invention. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0035] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the secondary control method of the P / V energy storage converter based on PI consistency in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The above-mentioned specific network example may include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0036] In this embodiment, a secondary control method of a P / V energy storage converter based on PI consistency is provided, which runs on a mobile terminal, a computer terminal or a similar computing device. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0037] Figure 2 1 is a flow chart of a secondary control method of a P / V energy storage converter based on PI consistency according to an embodiment of the present application. Figure 2 As shown, the method comprises the following steps:

[0038] Step S1, generating an output signal of a secondary controller through a PI consistency algorithm according to power state variables of each distributed power source and all distributed power sources communicating with it;

[0039] Step S2, based on the output signal, compensating and modifying the P / V droop control equation to obtain a voltage reference value and an angular frequency reference value;

[0040] Step S3, obtaining a modulation signal through an internal control loop based on the voltage reference value;

[0041] Step S4, based on the modulation signal and the angular frequency reference value, a switching control signal of the inverter switch tube is obtained through Park transformation and SPWM modulation to complete the distributed secondary control of the converter.

[0042] Through this embodiment, according to the power state variables of each distributed power source and all distributed power sources communicating with it, the output signal of the secondary controller is generated through the PI consistency algorithm. Based on the output signal, the P / V droop control equation is compensated and modified to obtain the voltage reference value and the angular frequency reference value. Based on the voltage reference value, a modulation signal is obtained through an internal control loop. Based on the modulation signal and the angular frequency reference value, the switching control signal of the inverter switch tube is obtained through Parker transformation and SPWM modulation to complete the distributed secondary control of the converter. Through the PI consistency algorithm, a power compensation signal is generated, which eliminates the uneven power distribution caused by the inconsistent line impedance from each distributed energy storage unit to the grid connection point PCC, adjusts the output power of each distributed energy storage unit, and effectively shortens the time required for control, avoids the communication delay problem, and effectively realizes power sharing and voltage and frequency recovery.

[0043] This example takes a low voltage power system as an example. Figure 3 As shown, a system structure diagram of a 380V low-voltage resistance power grid system consisting of three distributed energy storage units, local loads, line impedance, a grid-connected bus, user loads, and a communication network between distributed energy storage units is shown; the system includes a physical layer and a network layer; the physical layer includes distributed energy storage units, transmission lines, buses, and loads; the network layer includes a communication network for completing information exchange between distributed energy storage units.

[0044] Among them, DG1, DG2, and DG3 are distributed energy storage units. L1 , R L2 , R L3 is the resistance in the line impedance, L L1 , L L2 , L L3 It is the inductive reactance in the line impedance, load 1, load 2 and load 3 are local loads, load 4 is the user load, Bus1, Bus2 and Bus3 are the local grid connection points of the distributed energy storage units, and Bus4 is the total grid connection point of the three distributed energy storage units. DG1, DG2 and DG3 are connected through a communication network, and the communication network can realize the communication of power state variables between each distributed energy storage unit, thereby realizing the distributed secondary control of the P / V energy storage converter based on PI consistency.

[0045] For the above system structure and method structure, the control goal of the PI consistent P / V droop control method provided in this embodiment is to make each distributed energy storage unit in the system distribute power in the inverse proportion of the preset droop coefficient, minimize the deviation between the bus voltage and the rated voltage, and make the frequency effectively recover after the load is connected to the grid. The frequency is expected to be stable at 50Hz, and the active power and reactive power of the three distributed energy storage units are expected to be effectively distributed according to the set ratio of 1:1:2. The load adopts a constant impedance load, and the load at each power source is R Load =10Ω, L Load =10mH, line impedance is R L1 =0.6Ω, L L1 =0.3mH, R L1 =0.2Ω, L L1 =0.1mH, R L1 =0.4Ω, L L1 =0.2mH.

[0046] The distributed secondary control method architecture of the P / V energy storage converter based on PI consistency used in this example is as follows Figure 4 The method includes primary control and secondary control; the primary control adopts a droop control strategy, including droop control, inner loop voltage control, inner loop current control and pulse width modulation; the secondary control includes power regulation and voltage frequency control based on the PI consistency algorithm.

[0047] A distributed secondary control method for a P / V energy storage converter based on PI consistency provided by the present invention is described in detail below.

[0048] Step 1 includes: obtaining a compensation adjustment signal of a distributed secondary control output based on PI consistency.

[0049] Corresponding to S1.2: The purpose of the voltage controller based on PI consistency is to achieve power sharing while minimizing the deviation between the bus voltage and the rated value, the latter of which is described as:

[0050]

[0051] Where: u vi is the active power compensation signal output by the distributed secondary control; v di It is the voltage deviation caused by P / V droop control.

[0052] For the distributed secondary control of PI consistent voltage, firstly, the power regulation correction of each distributed energy storage unit is calculated according to the actual output power P and Q at the grid connection point.

[0053]

[0054] Where: R pi is the droop coefficient of P / V droop control, and its reciprocal is the desired power distribution coefficient of the i-th distributed energy storage unit; P i is the output active power of the i-th distributed energy storage unit.

[0055] Corresponding to S1.1: Each distributed energy storage unit sends the calculated power regulation correction for droop control to other adjacent distributed energy storage units through the communication network And receive the power adjustment correction sent by other adjacent distributed energy storage units Through and By performing difference and weighted summation, we can obtain the additional variable ζ introduced by the PI consistency algorithm. vi Each distributed energy storage unit sends a signal to other adjacent distributed energy storage units through the communication network. vi , and receive the ζ sent by other adjacent distributed energy storage units vj , thus obtaining the power compensation correction u calculated based on the PI consistency algorithm vi .

[0056]

[0057] Where: a p , b p , g p is the weight factor, N Ci is the set of all distributed energy storage units communicating with the i-th distributed energy storage unit, ζ vi It is an additional variable introduced by the consensus algorithm.

[0058] The distributed secondary controller principle of PI consistent voltage combines the active power consistency part and the voltage recovery part. The active power consistency part is actually composed of the proportional term and the integral term of PI, so the algorithm is named PI consistent controller. It will converge in steady state, eliminating the shared power error caused by line impedance.

[0059] Similarly, the distributed secondary controller based on PI consistency frequency is designed as follows:

[0060]

[0061] Where: a p , b p , g p is the weight factor, ζ ωiis an additional variable introduced by the consensus algorithm. Figure 4 As shown in Figure 1, the distributed secondary controller of PI consistent frequency has a similar control structure. However, unlike the voltage controller, the frequency controller only provides the same compensation correction to all distributed energy storage units for restoring the frequency, because the reactive power of all distributed energy storage units has converged to a stable state.

[0062] Step 2 includes: obtaining voltage and angular frequency reference values ​​based on P / V droop control.

[0063] Through the distributed secondary controller of voltage and frequency with PI consistency, the compensation correction of P / V and Q / f droop control is obtained. The mathematical model of P / V droop control is:

[0064]

[0065] Where: and Respectively represent the d-axis voltage and q-axis voltage reference values; V ref Indicates rated voltage; R pi and R qi They represent the droop coefficient of voltage control and the droop coefficient of frequency control respectively; P i and Q i Respectively represent active power and reactive power; u vi and u ωi They represent the compensation correction provided by the distributed secondary controller for P / V droop control and Q / f droop control respectively; Indicates the angular frequency reference value; ω ref Indicates the rated angular frequency.

[0066] Step 3 includes: obtaining a modulation signal through an internal control loop based on a voltage reference value.

[0067] Corresponding to S1.1: The calculation formula for the command value of the inductor current obtained by the i-th power supply inner loop voltage control is as follows:

[0068]

[0069] Where: k PV is the proportional coefficient of the PI controller, k IV is the integral coefficient of the PI controller, v oi is the output voltage sampling value, It is the voltage reference value of P / V droop control output.

[0070] Corresponding to S1.2: The calculation formula of the modulation signal obtained by the i-th power supply inner loop current controller is as follows:

[0071]

[0072] Where: k PC is the proportional coefficient of the PI controller, k IC is the integral coefficient of the PI controller, It is the current reference value output by the inner current loop.

[0073] Step 4 includes: obtaining a reference value of the output voltage by P / V droop control and frequency reference value ω * The on / off control signal of the inverter switch tube can be obtained through the internal loop and SPWM modulation.

[0074] According to the modulation signal output by the inner current loop, the modulation signal is transferred from the dq axis coordinate system to the abc three-phase synchronous rotating coordinate system through Park equation transformation, and then the switch off control signal of the energy storage converter is obtained through SPWM modulation.

[0075] In this example, a distributed secondary control method based on the PI consistency algorithm is used to generate a power compensation correction, and the P / V droop control is corrected with the power compensation correction. This eliminates the voltage and power distribution deviations inherent in the primary droop control, and achieves power and voltage control of the low-voltage resistor network. The output voltage of each distributed energy storage unit can be effectively controlled, and power distribution can be accurately achieved. While maintaining control performance, the amount of communication required for the operation of the distributed controller is reduced, the communication burden is reduced, and the control structure is simpler.

[0076] The hierarchical control method provided in the embodiment is compared with the traditional P / V droop control method in MATLAB / simulink software. Figure 5 and Figure 6 The simulation results are shown in Figure 2. Figure 5 , Figure 6 Figures (a), (b), (c), and (d) show the voltage, active power, frequency, and reactive power curves of each distributed unit output when the system only has P / V droop control. At 4s, the circuit breaker on bus 4 is closed and load 4 is connected to the system. Figure 5 The hierarchical control method provided in the embodiment is added at 2 seconds.

[0077] from Figure 5 From the voltage waveform shown in (a), it can be seen that when the droop control acts alone, the output voltage of each distributed energy storage unit has an inherent static deviation, and the voltage is in a steady state but lower than the rated value of 380V. After the load is connected at 4s, the voltage output by the distributed energy storage unit drops and stabilizes at a lower value. Figure 6From the voltage waveform shown in (a), it can be seen that when the distributed secondary control is added at 2s, the voltage is stabilized at 380V, and even when the load is added at 4s, the voltage can quickly recover and stabilize at 380V.

[0078] from Figure 5 The active and reactive power waveforms shown in (b) and (d) show that the power distribution is erroneous due to the influence of line impedance, and the proportional distribution is not achieved in accordance with the inverse ratio of the virtual droop coefficient (1:1:2). Figure 6 The active and reactive power curves shown in (b) and (d) show that the distributed control method provided in the embodiment takes effect after 2 seconds, and the output power distribution of the distributed energy storage unit is corrected. The load is connected at 4 seconds, and the output power is increased to maintain power balance. However, the steady-state power distribution between them always satisfies the power distribution ratio of 1:1:2, and accurate power distribution is achieved.

[0079] from Figure 5 (c) The frequency waveform shown in the figure shows that due to only one control, under the separate P / V control, the frequency of each distributed energy storage unit deviates from the rated value by 50Hz. When the load is connected at 4s, the frequency rises and stabilizes at a higher value. Figure 6 (c) The frequency curve shown in the figure shows that the distributed control method provided in the embodiment takes effect after 2 seconds, and the frequency of the distributed energy storage unit is stabilized at 50 Hz. Even after the load is connected, the frequency can quickly stabilize at the rated value of 50 Hz.

[0080] like Figure 7 (a) and (b) show the voltage and frequency compensation signals u generated by the PI consistency algorithm. vi and u ωi ,Under the intervention of the secondary controller or step load change, as the power output of the distributed energy storage unit increases, the power regulation correction increases accordingly, and the power compensation correction obtained based on the PI consistency algorithm also increases rapidly and reaches a stable state, compensating for the voltage and frequency deviations caused by the P / V droop control.

[0081] like Figure 8 (a), (b), and (c) show the voltage, active power, and frequency curves of each distributed energy storage unit output under a communication delay of 0.1s. The distributed secondary control method based on PI consistency provided in the embodiment is added at 2s, and the load 4 on the bus 4 is connected at 4s, that is, a load step occurs. Figure 7It can be seen that the system takes more time to stabilize with the addition of 0.1s communication delay, and an undesirable voltage drop occurs when load 4 is connected. Nevertheless, the system is eventually able to operate stably while ensuring the required voltage and frequency recovery and power sharing, which verifies the robustness of the second control based on PI consistency.

[0082] The embodiment of the present application also provides a secondary control device of a P / V energy storage converter based on PI consistency. It should be noted that the secondary control device of a P / V energy storage converter based on PI consistency in the embodiment of the present application can be used to execute the secondary control method for a P / V energy storage converter based on PI consistency provided in the embodiment of the present application. The device is used to implement the above-mentioned embodiments and preferred implementation modes, and those that have been described will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware for a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0083] The following introduces a secondary control device of a P / V energy storage converter based on PI consistency provided in an embodiment of the present application.

[0084] Fig. 9 Schematic diagram of a secondary control device of a P / V energy storage converter based on PI consistency according to an embodiment of the present application. Fig. 9 As shown, the device comprises:

[0085] A generating unit 10, for generating an output signal of a secondary controller according to a power state variable of each distributed power source and all distributed power sources communicating therewith through a PI consistency algorithm;

[0086] A compensation unit 20, configured to compensate and modify the P / V droop control equation based on the output signal to obtain a voltage reference value and an angular frequency reference value;

[0087] A first processing unit 30, configured to obtain a modulation signal through an internal control loop based on the voltage reference value;

[0088] The second processing unit 40 is used to obtain the switching control signal of the inverter switch tube based on the modulation signal and the angular frequency reference value through Park transformation and SPWM modulation to complete the distributed secondary control of the converter.

[0089] Through this embodiment, according to the power state variables of each distributed power source and all distributed power sources communicating with it, the output signal of the secondary controller is generated through the PI consistency algorithm. Based on the output signal, the P / V droop control equation is compensated and modified to obtain the voltage reference value and the angular frequency reference value. Based on the voltage reference value, a modulation signal is obtained through an internal control loop. Based on the modulation signal and the angular frequency reference value, the switching control signal of the inverter switch tube is obtained through Parker transformation and SPWM modulation to complete the distributed secondary control of the converter. Through the PI consistency algorithm, a power compensation signal is generated, which eliminates the uneven power distribution caused by the inconsistent line impedance from each distributed energy storage unit to the grid connection point PCC, adjusts the output power of each distributed energy storage unit, and effectively shortens the time required for control, avoids the communication delay problem, and effectively realizes power sharing and voltage and frequency recovery.

[0090] The secondary control device of the P / V energy storage converter based on PI consistency includes a processor and a memory, and the above-mentioned generating unit, compensation unit, first processing unit and second processing unit are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions. The above-mentioned modules are all located in the same processor; or, the above-mentioned modules are respectively located in different processors in the form of any combination.

[0091] The processor includes a kernel, which retrieves the corresponding program unit from the memory. One or more kernels can be set, and the P / V energy storage converter can be controlled secondary based on PI consistency by adjusting kernel parameters.

[0092] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0093] An embodiment of the present invention provides a computer-readable storage medium, which includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute the secondary control method of the P / V energy storage converter based on PI consistency.

[0094] Specifically, the secondary control method of the P / V energy storage converter based on PI consistency includes:

[0095] Step S1, generating an output signal of a secondary controller through a PI consistency algorithm according to power state variables of each distributed power source and all distributed power sources communicating with it;

[0096] Step S2, based on the output signal, compensating and modifying the P / V droop control equation to obtain a voltage reference value and an angular frequency reference value;

[0097] Step S3, obtaining a modulation signal through an internal control loop based on the voltage reference value;

[0098] Step S4, based on the modulation signal and the angular frequency reference value, a switching control signal of the inverter switch tube is obtained through Park transformation and SPWM modulation to complete the distributed secondary control of the converter.

[0099] An embodiment of the present invention provides a processor, which is used to run a program, wherein the secondary control method of the P / V energy storage converter based on PI consistency is executed when the program is running.

[0100] Specifically, the secondary control method of the P / V energy storage converter based on PI consistency includes:

[0101] Step S1, generating an output signal of a secondary controller through a PI consistency algorithm according to power state variables of each distributed power source and all distributed power sources communicating with it;

[0102] Step S2, based on the output signal, compensating and modifying the P / V droop control equation to obtain a voltage reference value and an angular frequency reference value;

[0103] Step S3, obtaining a modulation signal through an internal control loop based on the voltage reference value;

[0104] Step S4, based on the modulation signal and the angular frequency reference value, a switching control signal of the inverter switch tube is obtained through Park transformation and SPWM modulation to complete the distributed secondary control of the converter.

[0105] An embodiment of the present invention provides a device, the device including a processor, a memory, and a program stored in the memory and executable on the processor, and when the processor executes the program, at least the following steps are implemented:

[0106] Step S1, generating an output signal of a secondary controller through a PI consistency algorithm according to power state variables of each distributed power source and all distributed power sources communicating with it;

[0107] Step S2, based on the output signal, compensating and modifying the P / V droop control equation to obtain a voltage reference value and an angular frequency reference value;

[0108] Step S3, obtaining a modulation signal through an internal control loop based on the voltage reference value;

[0109] Step S4, based on the modulation signal and the angular frequency reference value, a switching control signal of the inverter switch tube is obtained through Park transformation and SPWM modulation to complete the distributed secondary control of the converter.

[0110] The devices in this article can be servers, PCs, PADs, mobile phones, etc.

[0111] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program for initializing at least the following method steps:

[0112] Step S1, generating an output signal of a secondary controller through a PI consistency algorithm according to power state variables of each distributed power source and all distributed power sources communicating with it;

[0113] Step S2, based on the output signal, compensating and modifying the P / V droop control equation to obtain a voltage reference value and an angular frequency reference value;

[0114] Step S3, obtaining a modulation signal through an internal control loop based on the voltage reference value;

[0115] Step S4, based on the modulation signal and the angular frequency reference value, a switching control signal of the inverter switch tube is obtained through Park transformation and SPWM modulation to complete the distributed secondary control of the converter.

[0116] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0117] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0118] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0119] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0120] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0121] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0122] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0123] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0124] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0125] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0126] 1) The secondary control method of the P / V energy storage converter based on PI consistency of the present application generates an output signal of the secondary controller through the PI consistency algorithm according to the power state variables of each distributed power source and all distributed power sources communicating with it. Based on the output signal, the P / V droop control equation is compensated and modified to obtain a voltage reference value and an angular frequency reference value. Based on the voltage reference value, a modulation signal is obtained through an internal control loop. Based on the modulation signal and the angular frequency reference value, the switching control signal of the inverter switch tube is obtained through Parker transformation and SPWM modulation to complete the distributed secondary control of the converter. Through the PI consistency algorithm, a power compensation signal is generated, which eliminates the uneven power distribution caused by the inconsistent line impedance from each distributed energy storage unit to the grid connection point PCC, adjusts the output power of each distributed energy storage unit, and effectively shortens the time required for control, avoids the communication delay problem, and effectively realizes power sharing and voltage and frequency recovery.

[0127] 2) The secondary control device of the P / V energy storage converter based on PI consistency of the present application generates an output signal of the secondary controller through the PI consistency algorithm according to the power state variables of each distributed power source and all distributed power sources communicating with it. Based on the output signal, the P / V droop control equation is compensated and modified to obtain a voltage reference value and an angular frequency reference value. Based on the voltage reference value, a modulation signal is obtained through an internal control loop. Based on the modulation signal and the angular frequency reference value, the switching control signal of the inverter switch tube is obtained through Parker transformation and SPWM modulation to complete the distributed secondary control of the converter. Through the PI consistency algorithm, a power compensation signal is generated, which eliminates the uneven power distribution caused by the inconsistent line impedance from each distributed energy storage unit to the grid connection point PCC, adjusts the output power of each distributed energy storage unit, and effectively shortens the time required for control, avoids the problem of communication delay, and effectively realizes power sharing and voltage and frequency recovery.

[0128] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A secondary control method for a P / V energy storage converter based on PI consistency, characterized in that: The method comprises the following steps: S1, generates an output signal of the secondary controller according to the power state variables of each distributed power source and all distributed power sources communicating with it through the PI consistency algorithm; S2, based on the output signal, compensating and modifying the P / V droop control equation to obtain a voltage reference value and an angular frequency reference value; S3, obtaining a modulation signal through an internal control loop based on the voltage reference value; S4, based on the modulation signal and the angular frequency reference value, the switching control signal of the inverter switch tube is obtained through Park transformation and SPWM modulation, so as to complete the distributed secondary control of the converter.

2. The method according to claim 1, characterized in that The S1 includes: S1.1, based on the power state variables and P / V control droop coefficients of each distributed power source and all distributed power sources communicating with it, obtain the additional variable ζ introduced by the PI consistency algorithm vi and ωi ; S1.2, based on additional variable ζ ωi The reactive power state variables of all distributed power sources that each distributed power source communicates with are used to obtain the reactive compensation correction value output by the secondary controller, thereby realizing the secondary control of the consistent frequency. vi The voltage compensation correction is obtained by calculating the active power state variables of all distributed power sources that each distributed power source communicates with. By setting the minimum deviation between the bus voltage and the voltage rating as the objective function, the active compensation signal output by the secondary controller is calculated, thereby realizing secondary control of the consistent voltage.

3. The method according to claim 2, characterized in that The S1.1 includes: According to the power state variables and P / V control droop coefficient of each distributed power source and all distributed power sources communicating with it, the deviation of the power distribution adjustment correction of each converter and the power distribution adjustment correction of all converters communicating with it is calculated and weighted summed up to obtain the additional variables introduced by the PI consistency algorithm.

4. The method according to claim 2, characterized in that: The S1.2 includes: Based on the additional variable ωi The reactive power state variables of all distributed power sources that each distributed power source communicates with are used to obtain the reactive compensation correction value output by the secondary controller according to the consistency algorithm model, thereby realizing the secondary control of the consistency frequency. vi The active power state variables of all distributed power sources that each distributed power source communicates with are calculated according to the consistency algorithm model, and the active power compensation signal output by the secondary controller is obtained by setting the minimum deviation between the bus voltage and the voltage rating as the objective function, thereby realizing secondary control of the consistency voltage.

5. The method according to claim 1, characterized in that The S2 includes: According to the active and reactive compensation signals output by the secondary controller, P / V droop control is introduced as an adjustment correction to obtain the voltage reference value and angular frequency reference value of the internal control loop.

6. The method according to claim 1, characterized in that The S3 includes: S3.1, based on the difference between the voltage reference value and the sampled value of the output voltage, the inverter output inductor current reference value is obtained through PI control of the voltage loop; S3.2, based on the difference between the inductor current reference value and the inductor current sampling value, a modulation signal is obtained through PI control of the current loop.

7. The method according to claim 6, characterized in that The S3.1 includes: Based on the sum of the reference voltage and the power distribution adjustment correction amount of each power supply minus the output voltage of the distributed power supply, the inverter output inductor current reference value is obtained through PI control.

8. The method according to claim 6, characterized in that The S3.2 includes: Based on the current reference value and the inductor current sampling value, the output voltage instruction of the distributed power supply is obtained through PI control.

9. The method according to claim 1, characterized in that: The S4 includes: Based on the modulation signal and the angular frequency reference value, a modulation signal is obtained through Park transformation, and a switching control signal of the switch tube is obtained through SPWM modulation.

10. A secondary control device for a P / V energy storage converter based on PI consistency, characterized in that: The device comprises: A generating unit, used for generating an output signal of a secondary controller according to power state variables of each distributed power source and all distributed power sources communicating with it through a PI consistency algorithm; A compensation unit, used for compensating and modifying a P / V droop control equation based on the output signal to obtain a voltage reference value and an angular frequency reference value; A first processing unit, configured to obtain a modulation signal through an internal control loop based on the voltage reference value; The second processing unit is used to obtain the switching control signal of the inverter switch tube based on the modulation signal and the angular frequency reference value through Park transformation and SPWM modulation to complete the distributed secondary control of the converter.

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