Control method and system based on decoupling bisynchronous coordinate system current controller

Abstract

The invention provides a control method and system based on a decoupling bisynchronous coordinate system current controller. The method comprises the following steps: acquiring a current value when a current power grid has a fault, and performing rotation transformation on the current value to obtain a positive sequence coordinate system current under a positive sequence coordinate system and a negative sequence coordinate system current under a negative sequence coordinate system; determining a dq-axis positive and negative sequence decoupling item of the positive sequence current controller, active and reactive decoupling feedforward items and a positive sequence voltage value required to be output by the positive sequence current controller; performing double inverse rotation transformation on the dq-axis positive and negative sequence decoupling item to obtain a positive sequence component under a negative sequence coordinate system; determining a negative sequence voltage value required to be output by the negative sequence current controller; and determining a control voltage reference value corresponding to the current value when the current power grid has a fault, and driving a power unit of the current controller to act based on the control voltage reference value. According to the technical scheme provided by the invention, the response speed and the control precision of the current controller under the power grid fault condition are improved.

Description

Technical Field

[0001] The present application relates to the technical field of current controller control, and in particular to a control method and system based on a decoupled dual synchronous coordinate system current controller. Background Art

[0002] The current injected into the grid under a grid fault is different from the current injected under normal operating conditions. In a single-phase system, a grid fault causes changes in the amplitude and phase angle of the single-phase voltage at the grid access point of the power converter. Therefore, the power converter also needs to change the amplitude and phase angle of the injected current to cross the fault. Usually, traditional current controllers in single-phase converters can cross faults well. However, faults in three-phase systems may cause asymmetric voltages in the three phases. Depending on the control target, the current injected into the grid may contain negative sequence components to aggravate the impact of the fault. Most traditional current controllers used in three-phase power converters are not suitable for injecting asymmetric currents, especially when the voltage is in an asymmetric state.

[0003] At present, for the current controller of the wind turbine grid-side converter, some studies have proposed the use of two control loops, one for positive-sequence current control and the other for negative-sequence current control. Unlike a single control loop, this control structure not only does not hinder system stability, but also improves system control performance and reduces steady-state errors. In this dual reference coordinate system, in order to independently control the positive-sequence and negative-sequence current vectors, the feedback voltage needs to be mapped to the positive-sequence and negative-sequence reference coordinate axes through Park transformation. Due to the interaction between the current vectors on the reference coordinate axes of different phase sequences, the signal obtained on the dq axis through Park transformation will have an oscillation of twice the fundamental frequency. When using this controller, the collected current needs to be separated from the positive and negative sequences, and the coordinate transformation, etc., which affects the response speed of the system to a certain extent, and the positive and negative sequence separation method used in the transformation process will also affect the control accuracy. Therefore, it is urgent to propose a solution that can perform high-speed and precise control of the current controller. Summary of the invention

[0004] The present application provides a control method and system based on a decoupled dual synchronous coordinate system current controller to at least solve the existing technical problems of low control speed and accuracy.

[0005] The first aspect of the present application provides a control method based on a decoupled dual synchronous coordinate system current controller, the method comprising:

[0006] Obtain the current value of the current grid fault and the active current reference value of the positive sequence current controller corresponding to the current value and reactive current reference value Active current reference value for negative sequence current controller and reactive current reference value and performing a rotation transformation on the current value to obtain a positive-sequence coordinate system current in a positive-sequence coordinate system and a negative-sequence coordinate system current in a negative-sequence coordinate system;

[0007] Determine the dq-axis positive-negative sequence decoupling term, active and reactive decoupling feedforward term of the positive-sequence current controller according to the active current reference value, reactive current reference value and positive-sequence coordinate system current in the positive-sequence coordinate system of the positive-sequence current controller, and determine the positive-sequence voltage value required to be output by the positive-sequence current controller based on the dq-axis positive-negative sequence decoupling term, active and reactive decoupling feedforward term of the positive-sequence current controller;

[0008] Performing a double reverse rotation transformation on the dq axis positive and negative sequence decoupling term to obtain a positive sequence component in a negative sequence coordinate system;

[0009] Determine the negative-sequence voltage value required to be output by the negative-sequence current controller according to the active current reference value and the reactive current reference value of the negative-sequence current controller, the positive-sequence component in the negative-sequence coordinate system and the negative-sequence coordinate system current in the negative-sequence coordinate system;

[0010] The control voltage reference value corresponding to the current value during the current grid fault is determined according to the positive-sequence voltage value required to be output by the positive-sequence current controller and the negative-sequence voltage value required to be output by the negative-sequence current controller, and the power unit of the current controller is driven to operate based on the control voltage reference value.

[0011] Preferably, the method of determining the dq-axis positive and negative sequence decoupling term, the active and reactive decoupling feedforward term of the positive sequence current controller according to the active current reference value, the reactive current reference value and the positive sequence coordinate system current in the positive sequence coordinate system comprises:

[0012] Obtaining a difference between an active current reference value of the positive-sequence current controller and an active current value in the positive-sequence coordinate system current, and using the difference as an active current error signal of the positive-sequence current controller;

[0013] Obtaining a difference between a reactive current reference value of the positive-sequence current controller and a reactive current value in the positive-sequence coordinate system current, and using the difference as a reactive current error signal of the positive-sequence current controller;

[0014] The active current reference value of the positive-sequence current controller is summed with the active current error signal of the positive-sequence current controller to obtain a d-axis positive-negative sequence decoupling term of the positive-sequence current controller;

[0015] The reactive current reference value of the positive-sequence current controller is summed with the reactive current error signal of the positive-sequence current controller to obtain the q-axis positive-negative sequence decoupling term of the positive-sequence current controller;

[0016] The product of the active current value in the positive sequence coordinate system current and the inductive reactance is used as the active decoupling feedforward term of the positive sequence current controller;

[0017] The product of the reactive current value in the positive-sequence coordinate system current and the inductive reactance is used as the reactive decoupling feedforward term of the positive-sequence current controller.

[0018] Further, the positive-sequence voltage value required to be output by the positive-sequence current controller is determined based on the dq-axis positive-negative sequence decoupling term and the active and reactive decoupling feedforward term of the positive-sequence current controller, including:

[0019] Determining the active voltage value of the positive sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the positive sequence current controller and the reactive decoupling feedforward term of the positive sequence current controller;

[0020] Determining the reactive voltage value of the positive sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the positive sequence current controller and the active decoupling feedforward term of the positive sequence current controller;

[0021] The active voltage value of the positive-sequence current controller and the reactive voltage value of the positive-sequence current controller are subjected to coordinate transformation to obtain the positive-sequence voltage value required to be output by the positive-sequence current controller.

[0022] Further, the method of determining the negative-sequence voltage value required to be output by the negative-sequence current controller according to the active current reference value and the reactive current reference value of the negative-sequence current controller, the positive-sequence component in the negative-sequence coordinate system, and the negative-sequence coordinate system current in the negative-sequence coordinate system includes:

[0023] Subtracting the positive sequence component in the negative sequence coordinate system from the negative sequence coordinate system current in the negative sequence coordinate system to obtain the negative sequence current of the negative sequence current controller;

[0024] Determine whether the active current reference value and the reactive current reference value of the negative-sequence current controller are zero, and when they are not zero, set the active current reference value and the reactive current reference value of the negative-sequence current controller to zero, and then obtain the active current error signal of the negative-sequence current controller and the reactive current error signal of the negative-sequence current controller;

[0025] Determine the d-axis positive-negative sequence decoupling term of the negative-sequence current controller, the q-axis positive-negative sequence decoupling term of the negative-sequence current controller, the active decoupling feedforward term of the negative-sequence current controller, and the reactive decoupling feedforward term of the negative-sequence current controller based on the active current error signal of the negative-sequence current controller, the reactive current error signal of the negative-sequence current controller, and the negative-sequence current of the sequence current controller;

[0026] The negative-sequence voltage value required to be output by the negative-sequence current controller is determined according to the d-axis positive-negative sequence decoupling term of the negative-sequence current controller, the q-axis positive-negative sequence decoupling term of the negative-sequence current controller, the active decoupling feedforward term of the negative-sequence current controller, and the reactive decoupling feedforward term of the negative-sequence current controller.

[0027] Further, the negative sequence voltage value required to be output by the negative sequence current controller is determined according to the d-axis positive and negative sequence decoupling term of the negative sequence current controller, the q-axis positive and negative sequence decoupling term of the negative sequence current controller, the active decoupling feedforward term of the negative sequence current controller, and the reactive decoupling feedforward term of the negative sequence current controller, including:

[0028] Determining the active voltage value of the negative sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the negative sequence current controller and the reactive decoupling feedforward term of the negative sequence current controller;

[0029] Determining the reactive voltage value of the negative sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the negative sequence current controller and the active decoupling feedforward term of the negative sequence current controller;

[0030] The active voltage value of the negative-sequence current controller and the reactive voltage value of the negative-sequence current controller are subjected to coordinate transformation to obtain the negative-sequence voltage value required to be output by the negative-sequence current controller.

[0031] The second aspect of the present application provides a control system based on a decoupled dual synchronous coordinate system current controller, including:

[0032] An acquisition module, used for acquiring the current value at the time of the current power grid fault and the active current reference value and reactive current reference value of the positive-sequence current controller and the active current reference value and reactive current reference value of the negative-sequence current controller corresponding to the current value, and performing a rotation transformation on the current value to obtain a positive-sequence coordinate system current in a positive-sequence coordinate system and a negative-sequence coordinate system current in a negative-sequence coordinate system;

[0033] A first determination module is used to determine the dq-axis positive-negative sequence decoupling item and the active and reactive decoupling feedforward item of the positive-sequence current controller according to the active current reference value, the reactive current reference value and the positive-sequence coordinate system current in the positive-sequence coordinate system of the positive-sequence current controller, and determine the positive-sequence voltage value required to be output by the positive-sequence current controller based on the dq-axis positive-negative sequence decoupling item and the active and reactive decoupling feedforward item of the positive-sequence current controller;

[0034] A transformation module, used for performing a double anti-rotation transformation on the dq axis positive and negative sequence decoupling term to obtain a positive sequence component in a negative sequence coordinate system;

[0035] A second determination module is used to determine the negative-sequence voltage value required to be output by the negative-sequence current controller according to the active current reference value and the reactive current reference value of the negative-sequence current controller, the positive-sequence component in the negative-sequence coordinate system and the negative-sequence coordinate system current in the negative-sequence coordinate system;

[0036] The third determination module is used to determine the control voltage reference value corresponding to the current value during the current power grid fault according to the positive-sequence voltage value required to be output by the positive-sequence current controller and the negative-sequence voltage value required to be output by the negative-sequence current controller, and drive the power unit of the current controller to operate based on the control voltage reference value.

[0037] Preferably, the first determining module is further used for:

[0038] Obtaining a difference between an active current reference value of the positive-sequence current controller and an active current value in the positive-sequence coordinate system current, and using the difference as an active current error signal of the positive-sequence current controller;

[0039] Obtaining a difference between a reactive current reference value of the positive-sequence current controller and a reactive current value in the positive-sequence coordinate system current, and using the difference as a reactive current error signal of the positive-sequence current controller;

[0040] The active current reference value of the positive-sequence current controller is summed with the active current error signal of the positive-sequence current controller to obtain a d-axis positive-negative sequence decoupling term of the positive-sequence current controller;

[0041] The reactive current reference value of the positive-sequence current controller is summed with the reactive current error signal of the positive-sequence current controller to obtain the q-axis positive-negative sequence decoupling term of the positive-sequence current controller;

[0042] The product of the active current value in the positive sequence coordinate system current and the inductive reactance is used as the active decoupling feedforward term of the positive sequence current controller;

[0043] The product of the reactive current value in the positive-sequence coordinate system current and the inductive reactance is used as the reactive decoupling feedforward term of the positive-sequence current controller.

[0044] Furthermore, the first determining module is further configured to:

[0045] Determining the active voltage value of the positive sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the positive sequence current controller and the reactive decoupling feedforward term of the positive sequence current controller;

[0046] Determining the reactive voltage value of the positive sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the positive sequence current controller and the active decoupling feedforward term of the positive sequence current controller;

[0047] The active voltage value of the positive-sequence current controller and the reactive voltage value of the positive-sequence current controller are subjected to coordinate transformation to obtain the positive-sequence voltage value required to be output by the positive-sequence current controller.

[0048] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in the first aspect is implemented.

[0049] A fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect of the present application.

[0050] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0051] The present application proposes a control method and system based on a decoupled dual-synchronous coordinate system current controller, the method comprising: obtaining the current value at the time of the current power grid fault and the active current reference value and reactive current reference value of the positive-sequence current controller, the active current reference value and reactive current reference value of the negative-sequence current controller corresponding to the current value, and performing a rotation transformation on the current value to obtain the positive-sequence coordinate system current in the positive-sequence coordinate system and the negative-sequence coordinate system current in the negative-sequence coordinate system; determining the dq-axis positive-negative sequence decoupling term, the active and reactive decoupling feedforward term of the positive-sequence current controller according to the active current reference value, reactive current reference value and the positive-sequence coordinate system current in the positive-sequence coordinate system, and The negative sequence decoupling term, active and reactive decoupling feedforward term determine the positive sequence voltage value required to be output by the positive sequence current controller; the dq axis positive and negative sequence decoupling term is subjected to double reverse rotation transformation to obtain the positive sequence component in the negative sequence coordinate system; the negative sequence voltage value required to be output by the negative sequence current controller is determined according to the active current reference value and reactive current reference value of the negative sequence current controller, the positive sequence component in the negative sequence coordinate system and the negative sequence coordinate system current in the negative sequence coordinate system; the control voltage reference value corresponding to the current value at the time of the current grid fault is determined according to the positive sequence voltage value required to be output by the positive sequence current controller and the negative sequence voltage value required to be output by the negative sequence current controller, and the power unit of the current controller is driven to act based on the control voltage reference value. The technical solution proposed in this application improves the response speed and control accuracy of the current controller in the case of grid fault.

[0052] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0054] Figure 1 A flow chart of a control method based on a decoupled dual synchronous coordinate system current controller according to an embodiment of the present application;

[0055] Figure 2 A schematic diagram of current control based on reference error signal decoupling according to an embodiment of the present application;

[0056] Figure 3 A schematic diagram of the simulation effect of active and reactive responses of a dual reference coordinate system current controller in a balanced high voltage ride through simulation at 1.3 times the nominal voltage according to an embodiment of the present application;

[0057] Figure 4 A schematic diagram of the simulation effect of active and reactive response of a decoupled dual synchronous reference coordinate system current controller in a balanced high voltage ride through simulation at 1.3 times the nominal voltage according to an embodiment of the present application;

[0058] Figure 5 A schematic diagram of the simulation effect of active and reactive responses of a dual reference coordinate system current controller in an unbalanced high voltage ride through simulation of 1.3 times the nominal voltage according to an embodiment of the present application;

[0059] Figure 6 A schematic diagram of the simulation effect of active and reactive response of a decoupled dual synchronous reference coordinate system current controller in an unbalanced high voltage ride through simulation of 1.3 times the nominal voltage according to an embodiment of the present application;

[0060] Figure 7 The present invention is a structural diagram of a control system based on a decoupled dual synchronous coordinate system current controller according to an embodiment of the present application. DETAILED DESCRIPTION

[0061] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0062] The present application proposes a control method and system based on a decoupled dual-synchronous coordinate system current controller, the method comprising: obtaining the current value at the time of the current power grid fault and the active current reference value and reactive current reference value of the positive-sequence current controller, the active current reference value and reactive current reference value of the negative-sequence current controller corresponding to the current value, and performing a rotation transformation on the current value to obtain the positive-sequence coordinate system current in the positive-sequence coordinate system and the negative-sequence coordinate system current in the negative-sequence coordinate system; determining the dq-axis positive-negative sequence decoupling term, the active and reactive decoupling feedforward term of the positive-sequence current controller according to the active current reference value, reactive current reference value and the positive-sequence coordinate system current in the positive-sequence coordinate system, and based on the dq-axis positive current reference value of the positive-sequence current controller The negative sequence decoupling term, active and reactive decoupling feedforward term determine the positive sequence voltage value required to be output by the positive sequence current controller; the dq axis positive and negative sequence decoupling term is subjected to double reverse rotation transformation to obtain the positive sequence component in the negative sequence coordinate system; the negative sequence voltage value required to be output by the negative sequence current controller is determined according to the active current reference value and reactive current reference value of the negative sequence current controller, the positive sequence component in the negative sequence coordinate system and the negative sequence coordinate system current in the negative sequence coordinate system; the control voltage reference value corresponding to the current value at the time of the current grid fault is determined according to the positive sequence voltage value required to be output by the positive sequence current controller and the negative sequence voltage value required to be output by the negative sequence current controller, and the power unit of the current controller is driven to act based on the control voltage reference value. The technical solution proposed in this application improves the response speed and control accuracy of the current controller in the case of grid fault.

[0063] The following describes a control method and system based on a decoupled dual synchronous coordinate system current controller according to an embodiment of the present application with reference to the accompanying drawings.

[0064] Embodiment 1

[0065] Figure 1 Flow chart of a control method based on a decoupled dual synchronous coordinate system current controller according to an embodiment of the present application. Figure 1 As shown, the method includes:

[0066] Step 1: Obtain the current value i when the current grid fails αβ and the current value i αβ The corresponding active current reference value of the positive sequence current controller and reactive current reference value Active current reference value for negative sequence current controller and reactive current reference value The current value is then rotated to obtain the positive sequence coordinate system current in the positive sequence coordinate system: and the negative sequence coordinate system current in the negative sequence coordinate system like Figure 2 shown.

[0067] Step 2: According to the active current reference value of the positive sequence current controller Reactive current reference value and the positive sequence coordinate system current in the positive sequence coordinate system Determine the dq-axis positive-negative sequence decoupling term, active and reactive decoupling feedforward term of the positive-sequence current controller, and determine the positive-sequence voltage value required to be output by the positive-sequence current controller based on the dq-axis positive-negative sequence decoupling term, active and reactive decoupling feedforward term of the positive-sequence current controller.

[0068] In the embodiments of the present disclosure, Figure 2 As shown, the active current reference value according to the positive sequence current controller Reactive current reference value and the positive sequence coordinate system current in the positive sequence coordinate system Determining the dq axis positive and negative sequence decoupling term, active and reactive decoupling feedforward term of the positive sequence current controller includes:

[0069] Obtain the difference between the active current reference value of the positive sequence current controller and the active current value in the positive sequence coordinate system current, and use the difference as the active current error signal of the positive sequence current controller

[0070] Obtain the difference between the reactive current reference value of the positive sequence current controller and the reactive current value in the positive sequence coordinate system current, and use the difference as the reactive current error signal of the positive sequence current controller

[0071] The active current reference value of the positive sequence current controller is summed with the active current error signal of the positive sequence current controller to obtain the d-axis positive and negative sequence decoupling term of the positive sequence current controller.

[0072] The reactive current reference value of the positive sequence current controller is summed with the reactive current error signal of the positive sequence current controller to obtain the q-axis positive and negative sequence decoupling term of the positive sequence current controller.

[0073] The active current value in the positive sequence coordinate system current is The product of the inductive reactance and the inductive reactance is used as the active decoupling feedforward term of the positive sequence current controller;

[0074] The reactive current value in the positive sequence coordinate system current The product of the inductive reactance and the inductive reactance is used as the reactive decoupling feedforward term of the positive sequence current controller.

[0075] In the embodiments of the present disclosure, Figure 2As shown, the positive sequence voltage value required to be output by the positive sequence current controller is determined based on the dq axis positive and negative sequence decoupling term and the active and reactive decoupling feedforward term of the positive sequence current controller, including:

[0076] Based on the d-axis positive and negative sequence decoupling term of the positive sequence current controller The difference between the reactive decoupling feedforward term of the positive sequence current controller and the reactive decoupling feedforward term of the positive sequence current controller determines the active voltage value of the positive sequence current controller;

[0077] The q-axis positive and negative sequence decoupling term based on the positive sequence current controller The reactive voltage value of the positive sequence current controller is determined by the difference between the reactive voltage value of the positive sequence current controller and the active decoupling feedforward term of the positive sequence current controller;

[0078] The active voltage value of the positive-sequence current controller and the reactive voltage value of the positive-sequence current controller are transformed to obtain the positive-sequence voltage value required to be output by the positive-sequence current controller.

[0079] Step 3: Perform a double reverse rotation transformation on the dq axis positive and negative sequence decoupling term to obtain the positive sequence component in the negative sequence coordinate system.

[0080] Step 4: According to the active current reference value of the negative sequence current controller and reactive current reference value The positive sequence component in the negative sequence coordinate system and the negative sequence coordinate system current in the negative sequence coordinate system determine the negative sequence voltage value required to be output by the negative sequence current controller.

[0081] In the embodiments of the present disclosure, Figure 2 As shown, the step 4 specifically includes:

[0082] 4.1 Subtract the positive sequence component in the negative sequence coordinate system from the negative sequence coordinate system current in the negative sequence coordinate system to obtain the negative sequence current of the negative sequence current controller

[0083] 4.2 Determining the active current reference value of the negative sequence current controller and whether the reactive current reference value is zero, and when it is not zero, setting the active current reference value and the reactive current reference value of the negative-sequence current controller to zero, and then obtaining the active current error signal of the negative-sequence current controller and the reactive current error signal of the negative-sequence current controller;

[0084] 4.3 Determine the d-axis positive-negative sequence decoupling term of the negative-sequence current controller, the q-axis positive-negative sequence decoupling term of the negative-sequence current controller, the active decoupling feedforward term of the negative-sequence current controller, and the reactive decoupling feedforward term of the negative-sequence current controller based on the active current error signal of the negative-sequence current controller, the reactive current error signal of the negative-sequence current controller, and the negative-sequence current of the sequence current controller;

[0085] Among them, the 4.3 specifically includes:

[0086] Obtaining the active current reference value of the negative current controller The active current value in the negative sequence coordinate system and uses the difference as the active current error signal of the negative sequence current controller.

[0087] Obtain the difference between the reactive current reference value of the negative sequence current controller and the reactive current value in the negative sequence coordinate system current, and use the difference as the reactive current error signal of the negative sequence current controller

[0088] The active current reference value of the negative sequence current controller and the active current error signal of the negative sequence current controller are summed to obtain the d-axis positive and negative sequence decoupling term of the negative sequence current controller.

[0089] The reactive current reference value of the negative-sequence current controller is subtracted from the reactive current error signal of the negative-sequence current controller to obtain the q-axis positive-negative sequence decoupling term of the negative-sequence current controller.

[0090] The active current value in the negative sequence coordinate system current is The product of the inductive reactance and the inductive reactance is used as the active decoupling feedforward term of the negative sequence current controller;

[0091] The reactive current value in the negative sequence coordinate system current The product of the inductive reactance and the inductive reactance is used as the reactive decoupling feedforward term of the negative sequence current controller.

[0092] 4.4 Determine the negative-sequence voltage value required to be output by the negative-sequence current controller based on the d-axis positive-negative sequence decoupling term of the negative-sequence current controller, the q-axis positive-negative sequence decoupling term of the negative-sequence current controller, the active decoupling feedforward term of the negative-sequence current controller, and the reactive decoupling feedforward term of the negative-sequence current controller.

[0093] The root 4.4 specifically includes:

[0094] Determining the active voltage value of the negative sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the negative sequence current controller and the reactive decoupling feedforward term of the negative sequence current controller;

[0095] Determining the reactive voltage value of the negative sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the negative sequence current controller and the active decoupling feedforward term of the negative sequence current controller;

[0096] The active voltage value of the negative-sequence current controller and the reactive voltage value of the negative-sequence current controller are subjected to coordinate transformation to obtain the negative-sequence voltage value required to be output by the negative-sequence current controller.

[0097] Step 5: Determine the control voltage reference value corresponding to the current value during the current grid fault according to the positive-sequence voltage value required to be output by the positive-sequence current controller and the negative-sequence voltage value required to be output by the negative-sequence current controller, and drive the power unit of the current controller to operate based on the control voltage reference value.

[0098] It should be noted that if Figure 2 As shown, αβ The current is transformed into the current in the positive sequence coordinate system after rotation, which is recorded as the positive sequence coordinate system current The current is transformed into the current in the negative sequence coordinate system after rotation, which is recorded as the negative sequence coordinate system current Active current reference for positive sequence current controller and reactive current reference Respectively with the positive sequence coordinate system current Make a difference and get the active current error signal and reactive current error signal Enter the PI regulator. Active current reference The low-pass filtered active current error signal Make and get the d-axis positive and negative sequence decoupling terms The product of the inductive reactance ωL is used as the active decoupling feedforward term, and the reactive current reference The error signal after the low pass filter Make the sum to get the q-axis positive and negative sequence decoupling terms The product multiplied by the inductive reactance ωL is used as the reactive decoupling feedforward term; and After double reverse rotation The positive sequence component in the negative sequence coordinate system is obtained, which is different from the current in the negative sequence coordinate system Take the difference to get the negative sequence current Active current reference for negative sequence current controller and reactive current reference Set to 0, the negative sequence current controller is the same as the positive sequence current controller described. Positive sequence current controller output After coordinate transformation get Negative sequence current controller output After coordinate transformation get After taking the sum, we get v αβ Enter the SVPWM debugging algorithm to drive the power unit to operate.

[0099] For example, the control effect simulation comparison of the dual reference coordinate system current controller and the decoupled dual synchronous reference coordinate system current controller is as follows:

[0100] The above two current controller models are used to simulate the balanced and unbalanced high voltage ride through of 1.3 times the nominal voltage. Figure 3 and Figure 4 The figures show the active and reactive responses of the two current controller models in the balanced high voltage ride-through simulation at 1.3 times the nominal voltage. As can be seen from the figure, the improved dual reference coordinate system current controller has a better reactive response speed, and the DC bus voltage and active current can also be well controlled. However, the active current oscillates due to overmodulation during the transient state when the high voltage is generated. The decoupled dual synchronous reference coordinate system current controller based on the reference signal and error signal decoupling network has a better control effect, which not only reduces the oscillation of the active current and the current impact during the transient state of high voltage ride-through, but also improves the reactive response speed. Figure 3 The reactive power response speed is 35ms. Figure 4 The reactive power response speed is 18ms.

[0101] like Figure 5 and Figure 6 The figures show the active and reactive responses of the two current controller models in the unbalanced high voltage ride-through simulation of 1.3 times the nominal voltage. It can be seen from the figure that compared with the improved dual reference coordinate system current controller, the current controller using the decoupled dual synchronous reference coordinate system based on the reference signal and error signal decoupling network can reduce the fluctuation of reactive current in steady state and the current impact in transient state, and has a faster reactive response speed.

[0102] According to the above analysis, the decoupled dual synchronous reference coordinate system current controller based on the reference signal and error signal decoupling network can meet the requirements and overcome the defects of the dual synchronous reference coordinate system current controller on the coordinate axis without sacrificing the dynamic performance.

[0103] The control method based on the decoupled dual synchronous coordinate system current controller proposed in this application has the following advantages:

[0104] First, the filtering link required to obtain positive and negative sequence currents is removed. Through the negative sequence current controller, the negative sequence component in the control current is zero. In steady state, the total current is all positive sequence current. The negative sequence current is obtained by subtracting the positive sequence reference value and the error current after low pass filtering from the current in the negative sequence coordinate system. Since the PI regulator forward channel reduces the lag link, the current control response speed is improved. Second, the current input of the cross-decoupling term adds a low-pass filter to avoid the interference of harmonic current on the controller output and improve the system stability.

[0105] In summary, the control method based on the decoupled dual synchronous coordinate system current controller proposed in this embodiment improves the response speed and control accuracy of the current controller in the event of a power grid fault.

[0106] Embodiment 2

[0107] Figure 7 FIG. 1 is a structural diagram of a control system based on a decoupled dual synchronous coordinate system current controller according to an embodiment of the present application, such as Figure 7 As shown, the system comprises:

[0108] An acquisition module 100 is used to acquire the current value at the time of the current power grid fault and the active current reference value and reactive current reference value of the positive-sequence current controller and the active current reference value and reactive current reference value of the negative-sequence current controller corresponding to the current value, and to perform a rotation transformation on the current value to obtain a positive-sequence coordinate system current in a positive-sequence coordinate system and a negative-sequence coordinate system current in a negative-sequence coordinate system;

[0109] A first determination module 200 is used to determine the dq axis positive and negative sequence decoupling items, active and reactive decoupling feedforward items of the positive sequence current controller according to the active current reference value, reactive current reference value and positive sequence coordinate system current in the positive sequence coordinate system of the positive sequence current controller, and determine the positive sequence voltage value required to be output by the positive sequence current controller based on the dq axis positive and negative sequence decoupling items, active and reactive decoupling feedforward items of the positive sequence current controller;

[0110] A transformation module 300 is used to perform a double reverse rotation transformation on the dq axis positive and negative sequence decoupling term to obtain a positive sequence component in a negative sequence coordinate system;

[0111] A second determination module 400 is used to determine the negative-sequence voltage value required to be output by the negative-sequence current controller according to the active current reference value and the reactive current reference value of the negative-sequence current controller, the positive-sequence component in the negative-sequence coordinate system, and the negative-sequence coordinate system current in the negative-sequence coordinate system;

[0112] The third determination module 500 is used to determine the control voltage reference value corresponding to the current value during the current power grid fault according to the positive-sequence voltage value required to be output by the positive-sequence current controller and the negative-sequence voltage value required to be output by the negative-sequence current controller, and drive the power unit of the current controller to operate based on the control voltage reference value.

[0113] In the embodiment of the present disclosure, the first determining module 200 is further configured to:

[0114] Obtaining a difference between an active current reference value of the positive-sequence current controller and an active current value in the positive-sequence coordinate system current, and using the difference as an active current error signal of the positive-sequence current controller;

[0115] Obtaining a difference between a reactive current reference value of the positive-sequence current controller and a reactive current value in the positive-sequence coordinate system current, and using the difference as a reactive current error signal of the positive-sequence current controller;

[0116] The active current reference value of the positive-sequence current controller is summed with the active current error signal of the positive-sequence current controller to obtain a d-axis positive-negative sequence decoupling term of the positive-sequence current controller;

[0117] The reactive current reference value of the positive-sequence current controller is summed with the reactive current error signal of the positive-sequence current controller to obtain the q-axis positive-negative sequence decoupling term of the positive-sequence current controller;

[0118] The product of the active current value in the positive sequence coordinate system current and the inductive reactance is used as the active decoupling feedforward term of the positive sequence current controller;

[0119] The product of the reactive current value in the positive-sequence coordinate system current and the inductive reactance is used as the reactive decoupling feedforward term of the positive-sequence current controller.

[0120] In the embodiment of the present disclosure, the first determining module 200 is further configured to:

[0121] Determining the active voltage value of the positive sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the positive sequence current controller and the reactive decoupling feedforward term of the positive sequence current controller;

[0122] Determining the reactive voltage value of the positive sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the positive sequence current controller and the active decoupling feedforward term of the positive sequence current controller;

[0123] The active voltage value of the positive-sequence current controller and the reactive voltage value of the positive-sequence current controller are subjected to coordinate transformation to obtain the positive-sequence voltage value required to be output by the positive-sequence current controller.

[0124] In the embodiment of the present disclosure, the second determining module 400 is further configured to:

[0125] The negative sequence current of the negative sequence current controller is obtained by subtracting the positive sequence component in the negative sequence coordinate system from the negative sequence coordinate system current.

[0126] Determine the active current reference value of the negative sequence current controller and whether the reactive current reference value is zero, and when it is not zero, setting the active current reference value and the reactive current reference value of the negative-sequence current controller to zero, and then obtaining the active current error signal of the negative-sequence current controller and the reactive current error signal of the negative-sequence current controller;

[0127] Determine the d-axis positive-negative sequence decoupling term of the negative-sequence current controller, the q-axis positive-negative sequence decoupling term of the negative-sequence current controller, the active decoupling feedforward term of the negative-sequence current controller, and the reactive decoupling feedforward term of the negative-sequence current controller based on the active current error signal of the negative-sequence current controller, the reactive current error signal of the negative-sequence current controller, and the negative-sequence current of the sequence current controller;

[0128] The negative-sequence voltage value required to be output by the negative-sequence current controller is determined according to the d-axis positive-negative sequence decoupling term of the negative-sequence current controller, the q-axis positive-negative sequence decoupling term of the negative-sequence current controller, the active decoupling feedforward term of the negative-sequence current controller, and the reactive decoupling feedforward term of the negative-sequence current controller.

[0129] Furthermore, the second determining module 400 is further configured to:

[0130] Determining the active voltage value of the negative sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the negative sequence current controller and the reactive decoupling feedforward term of the negative sequence current controller;

[0131] Determining the reactive voltage value of the negative sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the negative sequence current controller and the active decoupling feedforward term of the negative sequence current controller;

[0132] The active voltage value of the negative-sequence current controller and the reactive voltage value of the negative-sequence current controller are subjected to coordinate transformation to obtain the negative-sequence voltage value required to be output by the negative-sequence current controller.

[0133] In summary, the control system based on the decoupled dual synchronous coordinate system current controller proposed in this embodiment improves the response speed and control accuracy of the current controller in the event of a power grid fault.

[0134] Embodiment 3

[0135] In order to implement the above embodiments, the present disclosure further proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in Embodiment 1 is implemented.

[0136] Embodiment 4

[0137] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method described in the first embodiment is implemented.

[0138] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. 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 this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0139] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0140] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A current control method based on a decoupled dual synchronous coordinate system current controller, characterized in that: The method comprises: Obtaining the current value at the time of the current power grid fault and the active current reference value and reactive current reference value of the positive-sequence current controller and the active current reference value and reactive current reference value of the negative-sequence current controller corresponding to the current value, and performing a rotation transformation on the current value to obtain a positive-sequence coordinate system current in a positive-sequence coordinate system and a negative-sequence coordinate system current in a negative-sequence coordinate system; Determine the dq-axis positive-negative sequence decoupling term, active and reactive decoupling feedforward term of the positive-sequence current controller according to the active current reference value, reactive current reference value and positive-sequence coordinate system current in the positive-sequence coordinate system of the positive-sequence current controller, and determine the positive-sequence voltage value required to be output by the positive-sequence current controller based on the dq-axis positive-negative sequence decoupling term, active and reactive decoupling feedforward term of the positive-sequence current controller; Performing a double reverse rotation transformation on the dq axis positive and negative sequence decoupling term to obtain a positive sequence component in a negative sequence coordinate system; Determine the negative-sequence voltage value required to be output by the negative-sequence current controller according to the active current reference value and the reactive current reference value of the negative-sequence current controller, the positive-sequence component in the negative-sequence coordinate system and the negative-sequence coordinate system current in the negative-sequence coordinate system; The control voltage reference value corresponding to the current value during the current grid fault is determined according to the positive-sequence voltage value required to be output by the positive-sequence current controller and the negative-sequence voltage value required to be output by the negative-sequence current controller, and the power unit of the current controller is driven to operate based on the control voltage reference value.

2. The method according to claim 1, characterized in that The method of determining the dq axis positive and negative sequence decoupling term and the active and reactive decoupling feedforward term of the positive sequence current controller according to the active current reference value, the reactive current reference value and the positive sequence coordinate system current in the positive sequence coordinate system comprises: Obtaining a difference between an active current reference value of the positive-sequence current controller and an active current value in the positive-sequence coordinate system current, and using the difference as an active current error signal of the positive-sequence current controller; Obtaining a difference between a reactive current reference value of the positive-sequence current controller and a reactive current value in the positive-sequence coordinate system current, and using the difference as a reactive current error signal of the positive-sequence current controller; The active current reference value of the positive-sequence current controller is summed with the active current error signal of the positive-sequence current controller to obtain a d-axis positive-negative sequence decoupling term of the positive-sequence current controller; The reactive current reference value of the positive-sequence current controller is summed with the reactive current error signal of the positive-sequence current controller to obtain the q-axis positive-negative sequence decoupling term of the positive-sequence current controller; The product of the active current value in the positive sequence coordinate system current and the inductive reactance is used as the active decoupling feedforward term of the positive sequence current controller; The product of the reactive current value in the positive-sequence coordinate system current and the inductive reactance is used as the reactive decoupling feedforward term of the positive-sequence current controller.

3. The method according to claim 2, characterized in that The method of determining the positive-sequence voltage value required to be output by the positive-sequence current controller based on the dq-axis positive-negative sequence decoupling term and the active and reactive decoupling feedforward term of the positive-sequence current controller includes: Determining the active voltage value of the positive sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the positive sequence current controller and the reactive decoupling feedforward term of the positive sequence current controller; Determining the reactive voltage value of the positive sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the positive sequence current controller and the active decoupling feedforward term of the positive sequence current controller; The active voltage value of the positive-sequence current controller and the reactive voltage value of the positive-sequence current controller are subjected to coordinate transformation to obtain the positive-sequence voltage value required to be output by the positive-sequence current controller.

4. The method according to claim 3, characterized in that The active current reference value according to the negative sequence current controller and reactive current reference value The positive sequence component in the negative sequence coordinate system and the negative sequence coordinate system current in the negative sequence coordinate system determine the negative sequence voltage value required to be output by the negative sequence current controller, including: The negative sequence current of the negative sequence current controller is obtained by subtracting the positive sequence component in the negative sequence coordinate system from the negative sequence coordinate system current. Determine the active current reference value of the negative sequence current controller and whether the reactive current reference value is zero, and when it is not zero, setting the active current reference value and the reactive current reference value of the negative-sequence current controller to zero, and then obtaining the active current error signal of the negative-sequence current controller and the reactive current error signal of the negative-sequence current controller; Determine the d-axis positive-negative sequence decoupling term of the negative-sequence current controller, the q-axis positive-negative sequence decoupling term of the negative-sequence current controller, the active decoupling feedforward term of the negative-sequence current controller, and the reactive decoupling feedforward term of the negative-sequence current controller based on the active current error signal of the negative-sequence current controller, the reactive current error signal of the negative-sequence current controller, and the negative-sequence current of the sequence current controller; The negative-sequence voltage value required to be output by the negative-sequence current controller is determined according to the d-axis positive-negative sequence decoupling term of the negative-sequence current controller, the q-axis positive-negative sequence decoupling term of the negative-sequence current controller, the active decoupling feedforward term of the negative-sequence current controller, and the reactive decoupling feedforward term of the negative-sequence current controller.

5. The method according to claim 4, characterized in that Determining the negative sequence voltage value required to be output by the negative sequence current controller according to the d-axis positive and negative sequence decoupling term of the negative sequence current controller, the q-axis positive and negative sequence decoupling term of the negative sequence current controller, the active decoupling feedforward term of the negative sequence current controller, and the reactive decoupling feedforward term of the negative sequence current controller includes: Determining the active voltage value of the negative sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the negative sequence current controller and the reactive decoupling feedforward term of the negative sequence current controller; Determining the reactive voltage value of the negative sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the negative sequence current controller and the active decoupling feedforward term of the negative sequence current controller; The active voltage value of the negative-sequence current controller and the reactive voltage value of the negative-sequence current controller are subjected to coordinate transformation to obtain the negative-sequence voltage value required to be output by the negative-sequence current controller.

6. A current control system based on a decoupled dual synchronous coordinate system current controller, characterized in that: The system comprises: An acquisition module, used for acquiring the current value at the time of the current power grid fault and the active current reference value and reactive current reference value of the positive-sequence current controller and the active current reference value and reactive current reference value of the negative-sequence current controller corresponding to the current value, and performing a rotation transformation on the current value to obtain a positive-sequence coordinate system current in a positive-sequence coordinate system and a negative-sequence coordinate system current in a negative-sequence coordinate system; A first determination module is used to determine the dq-axis positive-negative sequence decoupling item and the active and reactive decoupling feedforward item of the positive-sequence current controller according to the active current reference value, the reactive current reference value and the positive-sequence coordinate system current in the positive-sequence coordinate system of the positive-sequence current controller, and determine the positive-sequence voltage value required to be output by the positive-sequence current controller based on the dq-axis positive-negative sequence decoupling item and the active and reactive decoupling feedforward item of the positive-sequence current controller; A transformation module, used for performing a double anti-rotation transformation on the dq axis positive and negative sequence decoupling term to obtain a positive sequence component in a negative sequence coordinate system; A second determination module is used to determine the negative-sequence voltage value required to be output by the negative-sequence current controller according to the active current reference value and the reactive current reference value of the negative-sequence current controller, the positive-sequence component in the negative-sequence coordinate system and the negative-sequence coordinate system current in the negative-sequence coordinate system; The third determination module is used to determine the control voltage reference value corresponding to the current value during the current power grid fault according to the positive-sequence voltage value required to be output by the positive-sequence current controller and the negative-sequence voltage value required to be output by the negative-sequence current controller, and drive the power unit of the current controller to operate based on the control voltage reference value.

7. The system according to claim 6, characterized in that The first determining module is further used for: Obtaining a difference between an active current reference value of the positive-sequence current controller and an active current value in the positive-sequence coordinate system current, and using the difference as an active current error signal of the positive-sequence current controller; Obtaining a difference between a reactive current reference value of the positive-sequence current controller and a reactive current value in the positive-sequence coordinate system current, and using the difference as a reactive current error signal of the positive-sequence current controller; The active current reference value of the positive-sequence current controller is summed with the active current error signal of the positive-sequence current controller to obtain a d-axis positive-negative sequence decoupling term of the positive-sequence current controller; The reactive current reference value of the positive-sequence current controller is summed with the reactive current error signal of the positive-sequence current controller to obtain the q-axis positive-negative sequence decoupling term of the positive-sequence current controller; The product of the active current value in the positive sequence coordinate system current and the inductive reactance is used as the active decoupling feedforward term of the positive sequence current controller; The product of the reactive current value in the positive-sequence coordinate system current and the inductive reactance is used as the reactive decoupling feedforward term of the positive-sequence current controller.

8. The system according to claim 7, characterized in that The first determining module is further used for: Determining the active voltage value of the positive sequence current controller based on the difference between the d-axis positive and negative sequence decoupling term of the positive sequence current controller and the reactive decoupling feedforward term of the positive sequence current controller; Determining the reactive voltage value of the positive sequence current controller based on the difference between the q-axis positive and negative sequence decoupling term of the positive sequence current controller and the active decoupling feedforward term of the positive sequence current controller; The active voltage value of the positive-sequence current controller and the reactive voltage value of the positive-sequence current controller are subjected to coordinate transformation to obtain the positive-sequence voltage value required to be output by the positive-sequence current controller.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 5 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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