A virtual synchronous machine based inverter control method and apparatus

Abstract

The application discloses an inverter control method and device based on a virtual synchronous machine, and when an inverter control request is received, reference data of the virtual synchronous machine is acquired and a measured voltage value of a filter to be measured is collected, a reference voltage value of the inverter is calculated according to the reference data, whether the measured voltage value exceeds an error range of the reference voltage value is compared, whether the measured voltage value is abnormal is judged, if the measured voltage value is abnormal, a control signal of the inverter is generated through a preset voltage control model, and the inverter is controlled to output a voltage value corresponding to the reference data through the control signal. In the control of the inverter operation, inertia and damping are considered, damage of a wind turbine generator set caused by a large disturbance is avoided, and power system stability is improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and in particular to an inverter control method and apparatus based on a virtual synchronous machine. Background Technology

[0002] With the rapid development of new energy sources, large-scale offshore wind power grid connection systems have received widespread attention as an important way to integrate new energy sources. These systems combine micro-sources, loads, and control devices into a controllable unit that can operate independently or be connected to the main power grid. Distributed power sources need to be connected to the system via inverters to supply power to the loads.

[0003] In existing technologies, inverter operation is mainly controlled through control methods such as PQ control and droop control.

[0004] However, in the aforementioned existing technologies, control methods such as PQ control and droop control control the operation of inverters without inertia and damping. Under large disturbances, this may cause complex resonance or oscillation, resulting in wind turbine tripping or even equipment damage, thus reducing the stability of the power system. Summary of the Invention

[0005] This invention provides an inverter control method and device based on a virtual synchronous machine, which solves the technical problem that existing technologies control inverter operation through PQ control, droop control and other control methods, which lack inertia and damping, and are prone to damage to wind turbines and reduce the stability of the power system under large disturbances.

[0006] This invention provides an inverter control method based on a virtual synchronous machine, characterized in that it involves a filter under test, wherein the filter under test is connected to the inverter, and the method includes:

[0007] In response to the inverter control request, the reference data of the virtual synchronous machine is obtained and the measured voltage value of the filter under test is acquired;

[0008] Calculate the reference voltage value of the inverter based on the reference data;

[0009] Compare the reference voltage value with the measured voltage value to determine whether the measured voltage value is abnormal;

[0010] If the measured voltage value is abnormal, a control signal for the inverter is generated through the preset voltage control model;

[0011] The inverter outputs a voltage value corresponding to the reference data by means of the control signal.

[0012] Optionally, the reference data includes voltage amplitude and switching angle, and the step of calculating the reference voltage value of the inverter based on the reference data includes:

[0013] Calculate the first sine value of the transformed angle;

[0014] Calculate the first multiplication factor between the first sine value and the voltage amplitude;

[0015] Calculate the first difference between the transformation angle and the angle threshold, and calculate the second sine value of the first difference;

[0016] Calculate the second multiplication factor between the second sine value and the voltage amplitude;

[0017] Calculate the first sum between the transformation angle and the angle threshold, and calculate the third sine value of the first sum;

[0018] Calculate the third multiplication factor between the third sine value and the voltage amplitude;

[0019] The first multiplication value, the second multiplication value, and the third multiplication value are determined as reference voltage values.

[0020] Optionally, the step of comparing the reference voltage value with the measured voltage value to determine whether the measured voltage value is abnormal includes:

[0021] Calculate the second difference between the reference voltage value and the measured voltage value, and determine the ratio of the second difference to the reference voltage value as the first error rate;

[0022] Determine whether the first error rate is greater than or equal to the voltage threshold;

[0023] If the first error rate is greater than or equal to the voltage threshold, the measured voltage value is determined to be abnormal.

[0024] If the first error rate is less than the voltage threshold, then the measured voltage value is determined to be normal.

[0025] Optionally, the voltage control model includes a rotating coordinate transformation model, a reactive voltage control model, and a dual-loop control model. The reference data also includes a current reference value. The step of generating a control signal for the inverter through the preset voltage control model if the measured voltage value is abnormal includes:

[0026] If the measured voltage value is abnormal, the reference voltage value, the reference current value, and the transformation angle are substituted into the rotating coordinate transformation model to calculate the d-axis output voltage value, q-axis output voltage value, d-axis output current value, and q-axis output current value.

[0027] Calculate the fourth multiplication value between the d-axis output voltage value, the q-axis output current value, and the preset power threshold;

[0028] Calculate the fifth multiplication value between the q-axis output voltage value, the d-axis output current value, and the preset power threshold;

[0029] Calculate the third difference between the fifth multiplier and the fourth multiplier, and determine the third difference as the reactive power value;

[0030] Substitute the reactive power value into the reactive voltage control model to calculate the output voltage reference value;

[0031] The output voltage reference value is input into the dual-loop control model to generate the control signal for the inverter.

[0032] Optionally, the reactive power voltage control model is specifically as follows:

[0033]

[0034] U qref =0-X d i d -ri q ;

[0035] Among them, G f For a low-pass filter, D qv This is the voltage reactive power droop factor. This is the reactive power reference value. U is the reactive power value. ref X is the voltage reference value. q For q-axis reactance, i q Let r be the q-axis current, r be the resistance, and i be the q-axis current. d X is the d-axis current. d For the d-axis reactance, U dref U is the reference value for the d-axis output voltage. qref This is the reference value for the q-axis output voltage.

[0036] Optionally, the rotation coordinate transformation model is specifically as follows:

[0037]

[0038]

[0039] Among them, U od U is the d-axis output voltage value. oq I is the q-axis output voltage value. od I is the d-axis output current value. oq The output current value is the q-axis, θ is the transformation angle, and u a Let u be the reference voltage value for phase a.b The reference voltage value for phase b, u c i is the reference voltage value for phase c. a Let i be the reference current value for phase a. b Let i be the reference current value for phase b. c This is the reference current value for phase c.

[0040] Optionally, the dual-loop control model is specifically as follows:

[0041] Voltage outer loop:

[0042] i dref =-ωCU oq +G V (s)(U dref -U od )+i od ;

[0043] i qref =-ωCU od +G V (s)(U qref -U oq )+i oq ;

[0044] Inner current loop:

[0045] e d =U od -ωLi q +G i (s)(i dref -i d );

[0046] e q =U oq -ωLi d +G i (s)(i qref -i q );

[0047] Among them, i dref i is the reference value for the d-axis output current of the voltage loop. qref Here, ω is the reference value for the q-axis output current of the voltage loop, ω is the mechanical angular frequency, C is the capacitance value, L is the inductance value, and U is the reference value for the q-axis output current. dref U is the reference value for the d-axis output voltage. qref U is the reference value for the q-axis output voltage. od U is the d-axis output voltage value. oq I is the q-axis output voltage value. oa I is the d-axis output current value. oq i is the q-axis output current value. d Let i be the d-axis current. q G is the q-axis current.V (s) is the voltage loop transfer function, G i (s) is the current loop transfer function, e d For d-axis control signal, e q This is the q-axis control signal.

[0048] A second aspect of the present invention provides an inverter control device based on a virtual synchronous machine, characterized in that it relates to a filter under test, the filter under test being connected to an inverter, and the device comprising:

[0049] The acquisition module is used to respond to inverter control requests, acquire reference data from the virtual synchronous machine, and acquire the measured voltage value of the filter under test;

[0050] The reference voltage calculation module is used to calculate the reference voltage value of the inverter based on reference data.

[0051] The comparison module is used to compare the reference voltage value with the measured voltage value to determine whether the measured voltage value is abnormal.

[0052] The control module is used to generate a control signal for the inverter based on the preset voltage control model if the measured voltage value is abnormal.

[0053] An execution module is used to control the inverter to output a voltage value corresponding to the reference data via the control signal.

[0054] Optionally, the reference data includes voltage amplitude and transformation angle, and the reference voltage calculation module includes:

[0055] The first sine calculation submodule is used to calculate the first sine value of the transformed angle;

[0056] The first multiplication calculation submodule is used to calculate the first multiplication value between the first sine value and the voltage amplitude.

[0057] The second sine calculation submodule is used to calculate the first difference between the transformation angle and the angle threshold, and to calculate the second sine value of the first difference.

[0058] The second multiplication calculation submodule is used to calculate the second multiplication value between the second sine value and the voltage amplitude.

[0059] The third sine calculation submodule is used to calculate the first sum between the transformation angle and the angle threshold, and to calculate the third sine value of the first sum.

[0060] The third multiplication calculation submodule is used to calculate the third multiplication value between the third sine value and the voltage amplitude.

[0061] The reference voltage calculation submodule is used to determine the first multiplication value, the second multiplication value, and the third multiplication value as the reference voltage value.

[0062] Optionally, the comparison module includes:

[0063] The first error rate calculation submodule is used to calculate the second difference between the reference voltage value and the measured voltage value, and to determine the ratio of the second difference to the reference voltage value as the first error rate.

[0064] The first judgment submodule is used to determine whether the first error rate is greater than or equal to the voltage threshold.

[0065] If the first error rate is greater than or equal to the voltage threshold, the measured voltage value is determined to be abnormal.

[0066] If the first error rate is less than the voltage threshold, then the measured voltage value is determined to be normal.

[0067] As can be seen from the above technical solutions, the present invention has the following advantages:

[0068] When the present invention receives an inverter control request, the technicians acquire reference data from the virtual synchronous machine and collect the measured voltage value of the filter under test. Using the reference data, they calculate the reference voltage value of the inverter and then compare whether the measured voltage value is within the range of the reference voltage value to determine whether the measured voltage value is abnormal. If the measured voltage value is abnormal, the inverter control is generated through a preset voltage control model. The inverter outputs a voltage value corresponding to the reference data through the control signal, thereby solving the technical problem in the prior art that large disturbances can cause damage to wind turbines and reduce the stability of the power system. Attached Figure Description

[0069] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0070] Figure 1 The flowchart illustrates the steps of an inverter control method based on a virtual synchronous machine, as provided in Embodiment 1 of the present invention.

[0071] Figure 2 The flowchart illustrates the steps of an inverter control method based on a virtual synchronous machine, as provided in Embodiment 2 of the present invention.

[0072] Figure 3This is a block diagram of the inverter control principle based on a virtual synchronous machine provided in Embodiment 2 of the present invention;

[0073] Figure 4 This is the equivalent circuit diagram of the reactive voltage control model provided in Embodiment 2 of the present invention;

[0074] Figure 5 The equivalent circuit diagram of the dual-loop control model provided in Embodiment 2 of the present invention;

[0075] Figure 6 This is a structural block diagram of an inverter control device based on a virtual synchronous machine, provided in Embodiment 3 of the present invention. Detailed Implementation

[0076] This invention provides an inverter control method and apparatus based on a virtual synchronous machine, which solves the technical problem that existing technologies using PQ control, droop control, and other control methods to control inverter operation lack inertia and damping, and are prone to damage to wind turbines and reduced power system stability under large disturbances.

[0077] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0078] Please see Figure 1 , Figure 1 This is a flowchart illustrating the steps of an inverter control method based on a virtual synchronous machine, as provided in Embodiment 1 of the present invention.

[0079] This invention provides an inverter control method based on a virtual synchronous machine, involving a filter under test connected to an inverter. The method includes:

[0080] Step 101: Respond to the inverter control request, obtain the reference data of the virtual synchronous machine, and collect the measured voltage value of the filter under test.

[0081] An inverter control request refers to a control request issued by a technician to adjust the output voltage of the inverter.

[0082] Virtual synchronous machine refers to a technology in which the control loop of the inverter adopts the electromechanical transient equations of a synchronous motor, enabling the grid-connected operation of devices using this technology to possess the inertia, damping characteristics, active power frequency regulation, and reactive power voltage regulation characteristics of grid-connected synchronous units.

[0083] Reference data refers to the control system's angle of change, reference voltage amplitude, and current reference value.

[0084] In this invention, when an inverter control request is received from a technician, the switching angle, reference voltage amplitude, and current reference value of the virtual synchronous machine are obtained, and the measured voltage value on the filter is acquired.

[0085] Step 102: Calculate the reference voltage value of the inverter based on the reference data.

[0086] The reference voltage value refers to the three-phase rated voltage value output by the inverter during normal operation.

[0087] In this invention, after obtaining the reference voltage amplitude and the transformation angle, the three-phase reference voltage value of the inverter can be obtained by calculating the product of the sine value of the transformation angle and the reference voltage amplitude.

[0088] Step 103: Compare the reference voltage value with the measured voltage value to determine if the measured voltage value is abnormal.

[0089] In this invention, the measured voltage value is compared with the reference voltage value range to determine whether the measured voltage value is abnormal.

[0090] It should be noted that when the inverter is working normally, the output voltage value is not a fixed constant, but will fluctuate within a range. When the measured voltage value exceeds the range of the reference voltage value, it indicates that the measured voltage value is abnormal.

[0091] Step 104: If the measured voltage value is abnormal, the inverter control signal is generated through the preset voltage control model.

[0092] The preset voltage control model refers to a voltage control model composed of a rotating coordinate transformation model, a reactive voltage control model, and a dual-loop control model. The rotating coordinate transformation model converts the reference voltage and reference current values ​​into d-axis output voltage, q-axis output voltage, d-axis output current, and q-axis output current values. The reactive power is calculated from the output voltage and output current values. The reactive power is input into the reactive voltage control model to calculate the output voltage reference value. The calculated output voltage reference value is then input into the dual-loop control model to generate the inverter control signal.

[0093] The control signal refers to the IGBT control switching signal of the inverter.

[0094] In this invention, when an abnormal measured voltage value is detected, a reference voltage value is input into a preset voltage control model, and the reference voltage value is converted into a control switching signal for the inverter.

[0095] Step 105: Control the inverter output voltage value corresponding to the reference data through the control signal.

[0096] In this invention, after receiving the control switch signal, the inverter is controlled to close and open, so that the inverter output voltage value remains within the reference voltage value range.

[0097] In this invention, when an inverter control request is received from a technician, the switching angle, reference voltage amplitude, and current reference value of the virtual synchronous machine are acquired, and the measured voltage value on the filter is collected. The three-phase reference voltage value of the inverter is obtained by calculating the product of the sine of the switching angle and the reference voltage amplitude. The measured voltage value is then compared to see if it falls within the reference voltage range to determine if it is abnormal. If abnormal, the reference voltage value and reference current value are input into a preset voltage control model to generate control switching signals for the inverter's IGBTs. The inverter output voltage is then controlled according to these signals to maintain the output voltage within the reference voltage range. This solves the technical problem that controlling inverter operation through PQ control, droop control, etc., lacks inertia and damping, easily causing damage to wind turbines and reducing power system stability under large disturbances. It avoids the situation where wind turbines are easily damaged under large disturbances, thus improving the stability of the power system.

[0098] Please see Figure 2 , Figure 2 This is a flowchart illustrating the steps of an inverter control method based on a virtual synchronous machine, as provided in Embodiment 2 of the present invention.

[0099] This invention provides an inverter control method based on a virtual synchronous machine, involving a filter under test connected to an inverter. The method includes:

[0100] Step 201: Respond to the inverter control request, obtain the reference data of the virtual synchronous machine, and collect the measured voltage value of the filter under test.

[0101] Please see Figure 3 , Figure 3 The block diagram of the inverter control principle based on the virtual synchronous machine is shown below. First, the output current and voltage of the filter are collected. The active power and reactive power are calculated by the power calculation stage and fed back to the virtual synchronous machine VSG control unit. Then, the virtual synchronous machine VSG control unit performs frequency control and voltage control. The output conversion angle and reference voltage value are then input to the voltage loop and current loop dual-loop control to form a control signal. The control signal is then transmitted to the triangular wave PWM generator to generate the inverter DG1 control switch model. The control switch model is input to DG1 to control the inverter output voltage. The output voltage is filtered by the filter and the double-circuit line impedance and then fed into the grid.

[0102] The measured voltage value refers to the three-phase voltage value output by the inverter.

[0103] In this invention, when an inverter control request is received from a technician, the switching angle, reference voltage amplitude, and current reference value of the control system are obtained through a virtual synchronous machine, and the measured voltage value on the filter under test is collected.

[0104] Step 202: Calculate the reference voltage value of the inverter based on the reference data.

[0105] Furthermore, step 202 may include the following sub-steps:

[0106] S11. Calculate the first sine value of the transformation angle.

[0107] The first sine value refers to the sine value of phase a of the three-phase voltage.

[0108] S12. Calculate the first multiplication value between the first sine value and the voltage amplitude.

[0109] S13. Calculate the first difference between the transformation angle and the angle threshold, and calculate the second sine value of the first difference.

[0110] Angle threshold refers to the angle difference between each phase of a three-phase voltage. For example, phase a is 120 degrees away from phase b, phase b is 120 degrees away from phase c, and phase c is 120 degrees away from phase a.

[0111] S14. Calculate the second multiplication value between the second sine value and the voltage amplitude.

[0112] The second sine value refers to the sine value of phase b of the three-phase voltage.

[0113] S15. Calculate the first sum between the transformation angle and the angle threshold, and calculate the third sine value of the first sum.

[0114] The third sine value refers to the sine value of phase c of the three-phase voltage.

[0115] S16. Calculate the third multiplication factor between the third sine value and the voltage amplitude.

[0116] S17. Determine the first multiplication value, the second multiplication value, and the third multiplication value as the reference voltage value.

[0117] In this invention, when the transformation angle and reference voltage amplitude of the virtual synchronizer are obtained, the first sine value of the transformation angle is calculated. By calculating the first multiplication of the first sine value and the voltage amplitude, the first multiplication is determined as the reference voltage value of phase a. The first difference between the transformation angle and 120 degrees is calculated. Then, the second sine value of the first difference is calculated. The second multiplication of the second sine value and the voltage amplitude is determined as the reference voltage value of phase b. The first sum between the transformation angle and 120 degrees is calculated. Then, the third sine value of the first sum is calculated. The third multiplication of the third sine value and the voltage amplitude is determined as the reference voltage value of phase c.

[0118] It should be noted that the reference voltage values ​​include the reference voltage values ​​for phase a, phase b, and phase c.

[0119] Step 203: Calculate the second difference between the reference voltage value and the measured voltage value, and determine the ratio of the second difference to the reference voltage value as the first error rate.

[0120] The first error rate refers to the deviation range between the measured actual voltage value and the reference voltage value, used to determine whether the measured voltage value is abnormal.

[0121] In this invention, after calculating the reference voltage value, the ratio of the second difference between the reference voltage value and the measured voltage value is determined as the first error rate.

[0122] Step 204: Determine whether the first error rate is greater than or equal to the voltage threshold.

[0123] Voltage threshold refers to the rated deviation range between the measured voltage value and the reference voltage value, which is generally 5%-10%.

[0124] In this invention, when the voltage threshold is set to 10%, after calculating the first error rate, it is determined whether the measured voltage value is abnormal by judging whether the first error rate is greater than or equal to 10%.

[0125] Step 205: If the first error rate is greater than or equal to the voltage threshold, the measured voltage value is determined to be abnormal.

[0126] In this invention, when the voltage threshold is set to 10%, if the first error rate is greater than or equal to 10%, the measured voltage value is determined to be abnormal.

[0127] Step 206: If the first error rate is less than the voltage threshold, then the measured voltage value is considered normal.

[0128] In this invention, when the voltage threshold is set to 10%, if the first error rate is less than 10%, the measured voltage value is determined to be normal.

[0129] Step 207: If the measured voltage value is abnormal, the inverter control signal is generated through the preset voltage control model.

[0130] Furthermore, step 207 may include the following sub-steps:

[0131] S21. If the measured voltage value is abnormal, substitute the reference voltage value, reference current value, and transformation angle into the rotating coordinate transformation model to calculate the d-axis output voltage value, q-axis output voltage value, d-axis output current value, and q-axis output current value.

[0132] The rotating coordinate transformation model refers to a mathematical model that transforms the three-phase reference voltage and reference current values ​​(a, b, c) into two-phase values. It uses one of the phases (a, b, c) as a reference, and the other two phases become components perpendicular to it, thus transforming the three-phase into two-phase.

[0133] In this invention, when the measured voltage value is abnormal, the reference voltage value, reference current value, and transformation angle are input into the rotating coordinate transformation model to convert the reference voltage values ​​of phase a, phase b, and phase c into d-axis output voltage values ​​and q-axis output voltage values, and the reference current values ​​of phase a, phase b, and phase c into d-axis output current values ​​and q-axis output current values.

[0134] S22. Calculate the fourth multiplication value between the d-axis output voltage value, the q-axis output current value, and the preset power threshold.

[0135] The preset power threshold refers to the power constant used to calculate the active and reactive power output of the inverter. For example, the preset power threshold is 1.5.

[0136] In this invention, when the converted d-axis output voltage value and q-axis output current value are obtained, the fourth multiplication value between the d-axis output voltage value, the q-axis output current value and 1.5 is calculated.

[0137] S23. Calculate the fifth multiplication value between the q-axis output voltage value, the d-axis output current value, and the preset power threshold.

[0138] In this invention, when the converted q-axis output voltage value and d-axis output current value are obtained, the fifth multiplier between the q-axis output voltage value, the d-axis output current value and 1.5 is calculated.

[0139] S24. Calculate the third difference between the fifth and fourth multiplication values, and determine the third difference as the reactive power value.

[0140] In this invention, after calculating the fourth and fifth multiplication values, the third difference between the fifth and fourth multiplication values ​​is determined as the reactive power value.

[0141] S25. Substitute the reactive power value into the reactive voltage control model to calculate the output voltage reference value.

[0142] Please see Figure 4 The calculated reactive power value Q is input into the reactive voltage control model for droop control. The output voltage reference value is obtained by multiplying the difference between the reactive power value and the grid voltage by the voltage feedback coefficient.

[0143] In this invention, after the reactive power value is calculated, the reactive power value is output to the reactive voltage control model to calculate the output voltage reference value.

[0144] S26. Input the output voltage reference value into the dual-loop control model to generate the inverter control signal.

[0145] Please see Figure 5 , Figure 5 For the equivalent model of the voltage outer loop and current inner loop, the q-axis output voltage reference value U is used. qref and d-axis output voltage reference value U dref The input is fed into the voltage outer loop control model to calculate the d-axis output current reference value i of the voltage loop output. dref and q-axis output current reference value i qref Then set the d-axis output current reference value i dref and q-axis output current reference value i qref Input to the inner current loop to calculate the d-axis control signal e. d and q-axis control signal e q .

[0146] In this invention, when the output voltage reference value is calculated, the q-axis output voltage reference value U is... qref and d-axis output voltage reference value U dref The input is fed into the dual-loop control model to calculate the d-axis control signal e. d and q-axis control signal e q .

[0147] Step 208: Control the inverter output voltage value corresponding to the reference data through the control signal.

[0148] In this invention, when the d-axis control signal e is calculated... d and q-axis control signal e q The inverter output voltage value will be controlled according to the output control signal, which corresponds to the reference voltage amplitude and the conversion angle.

[0149] In this invention, when an inverter control request is received, the voltage amplitude, switching angle, and reference current value of the virtual synchronous machine are acquired, and the measured voltage value of the filter under test is collected. Based on the voltage amplitude and switching angle, the reference voltage value of the inverter is calculated. The first error rate between the measured voltage value and the reference voltage value is calculated. By judging whether the first error rate is greater than or equal to the voltage threshold, it is determined whether the measured voltage value is abnormal. If the first error rate is greater than or equal to the voltage threshold, the measured voltage value is determined to be abnormal. The calculated reference voltage value is input into a preset voltage control model to generate a control signal for the inverter. The inverter outputs a voltage value corresponding to the voltage amplitude and switching angle through the control signal. This solves the technical problem that controlling the inverter operation through PQ control, droop control, and other control methods lacks inertia and damping, which can easily cause damage to wind turbines and reduce the stability of the power system under large disturbances. It avoids the situation where wind turbines are easily damaged under large disturbances and improves the stability of the power system.

[0150] Please see Figure 6 , Figure 6 This is a structural block diagram of an inverter control device based on a virtual synchronous machine, provided in Embodiment 3 of the present invention.

[0151] This invention provides an inverter control device based on a virtual synchronous machine, relating to a filter under test, wherein the filter under test is connected to the inverter, and the device includes:

[0152] The acquisition module 601 is used to respond to inverter control requests, acquire reference data from the virtual synchronous machine, and acquire the measured voltage value of the filter under test.

[0153] The reference voltage calculation module 602 is used to calculate the reference voltage value of the inverter based on reference data.

[0154] The comparison module 603 is used to compare the reference voltage value with the measured voltage value to determine whether the measured voltage value is abnormal.

[0155] The control module 604 is used to generate a control signal for the inverter based on a preset voltage control model if the measured voltage value is abnormal.

[0156] The execution module 605 is used to control the inverter output voltage value corresponding to the reference data through control signals.

[0157] Furthermore, the reference data includes voltage amplitude and transformation angle, and the reference voltage calculation module 602 includes:

[0158] The first sine calculation submodule is used to calculate the first sine value of the transformation angle;

[0159] The first multiplication calculation submodule is used to calculate the first multiplication value between the first sine value and the voltage amplitude.

[0160] The second sine calculation submodule is used to calculate the first difference between the transformation angle and the angle threshold, and to calculate the second sine value of the first difference;

[0161] The second multiplication calculation submodule is used to calculate the second multiplication value between the second sine value and the voltage amplitude.

[0162] The third sine calculation submodule is used to calculate the first sum between the transformation angle and the angle threshold, and to calculate the third sine value of the first sum.

[0163] The third multiplication calculation submodule is used to calculate the third multiplication value between the third sine value and the voltage amplitude.

[0164] The reference voltage calculation submodule is used to determine the first multiplication value, the second multiplication value, and the third multiplication value as the reference voltage value.

[0165] Furthermore, the comparison module 603 includes:

[0166] The first error rate calculation submodule is used to calculate the second difference between the reference voltage value and the measured voltage value, and the ratio of the second difference to the reference voltage value is determined as the first error rate.

[0167] The first judgment submodule is used to determine whether the first error rate is greater than or equal to the voltage threshold.

[0168] If the first error rate is greater than or equal to the voltage threshold, the measured voltage value is determined to be abnormal.

[0169] If the first error rate is less than the voltage threshold, the measured voltage value is considered normal.

[0170] Furthermore, the voltage control model includes a rotating coordinate transformation model, a reactive voltage control model, and a dual-loop control model. The control module 604 includes:

[0171] The coordinate transformation submodule is used to substitute the reference voltage value, reference current value, and transformation angle into the rotating coordinate transformation model if the measured voltage value is abnormal, and calculate the d-axis output voltage value, q-axis output voltage value, d-axis output current value, and q-axis output current value.

[0172] The fourth multiplication calculation submodule is used to calculate the fourth multiplication value between the d-axis output voltage value, the q-axis output current value, and the preset power threshold.

[0173] The fifth multiplier calculation submodule is used to calculate the fifth multiplier between the q-axis output voltage value, the d-axis output current value, and the preset power threshold.

[0174] The reactive power calculation submodule is used to calculate the third difference between the fifth and fourth multiplication values, and to determine the third difference as the reactive power value.

[0175] The voltage data analysis submodule is used to substitute the reactive power value into the reactive voltage control model and calculate the output voltage reference value.

[0176] The signal generation submodule is used to input the output voltage reference value into the dual-loop control model to generate the control signal for the inverter.

[0177] In this embodiment of the invention, when the acquisition model receives an inverter control request from the operator, it acquires reference data from the virtual synchronous machine and collects the measured voltage value of the filter under test. Then, the reference voltage calculation module calculates the reference voltage value of the inverter based on the reference data. The comparison module then compares the measured voltage value with the reference voltage value to determine if the measured voltage value is abnormal. If an abnormality is detected, the control module generates a control signal for the inverter using a preset voltage control model. The execution module then controls the inverter to output the voltage value corresponding to the reference data. This solves the technical problem that controlling inverter operation using PQ control, droop control, and other control methods lacks inertia and damping, making it prone to damage to wind turbines and reducing power system stability under large disturbances. It avoids the situation where wind turbines are easily damaged under large disturbances, thus improving the stability of the power system.

[0178] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and unit can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0179] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0180] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0181] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An inverter control method based on a virtual synchronous machine, characterized in that... The method involves a filter under test, which is connected to an inverter, and includes: In response to the inverter control request, the reference data of the virtual synchronous machine is obtained and the measured voltage value of the filter under test is acquired; Calculate the reference voltage value of the inverter based on the reference data; Compare the reference voltage value with the measured voltage value to determine whether the measured voltage value is abnormal; If the measured voltage value is abnormal, a control signal for the inverter is generated through a preset voltage control model; The inverter is controlled by the control signal to output a voltage value corresponding to the reference data. The step of comparing the reference voltage value with the measured voltage value to determine whether the measured voltage value is abnormal includes: Calculate the second difference between the reference voltage value and the measured voltage value, and determine the ratio of the second difference to the reference voltage value as the first error rate; Determine whether the first error rate is greater than or equal to the voltage threshold; If the first error rate is greater than or equal to the voltage threshold, the measured voltage value is determined to be abnormal. If the first error rate is less than the voltage threshold, then the measured voltage value is determined to be normal. The voltage control model includes a rotating coordinate transformation model, a reactive voltage control model, and a dual-loop control model. The reference data includes reference current value, voltage amplitude, and transformation angle. The step of generating the inverter's control signal through the preset voltage control model if the measured voltage value is abnormal includes: If the measured voltage value is abnormal, the reference voltage value, the reference current value, and the transformation angle are substituted into the rotating coordinate transformation model to calculate the d-axis output voltage value, q-axis output voltage value, d-axis output current value, and q-axis output current value. Calculate the fourth multiplication value between the d-axis output voltage value, the q-axis output current value, and the preset power threshold; Calculate the fifth multiplication value between the q-axis output voltage value, the d-axis output current value, and the preset power threshold; Calculate the third difference between the fifth multiplier and the fourth multiplier, and determine the third difference as the reactive power value; Substitute the reactive power value into the reactive voltage control model to calculate the output voltage reference value; The output voltage reference value is input into the dual-loop control model to generate the control signal for the inverter.

2. The inverter control method based on a virtual synchronous machine according to claim 1, characterized in that, The step of calculating the reference voltage value of the inverter based on reference data includes: Calculate the first sine value of the transformed angle; Calculate the first multiplication factor between the first sine value and the voltage amplitude; Calculate the first difference between the transformation angle and the angle threshold, and calculate the second sine value of the first difference; Calculate the second multiplication factor between the second sine value and the voltage amplitude; Calculate the first sum between the transformation angle and the angle threshold, and calculate the third sine value of the first sum; Calculate the third multiplication factor between the third sine value and the voltage amplitude; The first multiplication value, the second multiplication value, and the third multiplication value are determined as reference voltage values.

3. The inverter control method based on a virtual synchronous machine according to claim 1, characterized in that, The reactive power voltage control model is specifically as follows: ; ; in, It is a low-pass filter. This is the voltage reactive power droop factor. This is the reactive power reference value. This is the reactive power value. This is the voltage reference value. For q-axis reactance, Let r be the q-axis current and r be the resistance. For d-axis current, For d-axis reactance, This is the reference value for the d-axis output voltage. This is the reference value for the q-axis output voltage.

4. The inverter control method based on a virtual synchronous machine according to claim 1, characterized in that, The rotation coordinate transformation model is specifically as follows: ; ; in, This represents the d-axis output voltage value. This represents the q-axis output voltage value. This represents the d-axis output current value. This is the q-axis output current value. For the transformation angle, This is the reference voltage value for phase a. This is the reference voltage value for phase b. This is the reference voltage value for phase c. This is the reference current value for phase a. This is the reference current value for phase b. This is the reference current value for phase c.

5. The inverter control method based on a virtual synchronous machine according to claim 1, characterized in that, The dual-loop control model is specifically as follows: Voltage outer loop: ； ； Inner current loop: ； ； in, This is the reference value for the d-axis output current of the voltage loop. This is the reference value for the q-axis output current of the voltage loop. For mechanical angular frequency, This is the capacitance value. This is the inductance value. This is the reference value for the d-axis output voltage. This is the reference value for the q-axis output voltage. This represents the d-axis output voltage value. This represents the q-axis output voltage value. This represents the d-axis output current value. This is the q-axis output current value. For d-axis current, For q-axis current, The voltage loop transfer function, The current loop transfer function, This is the d-axis control signal. This is the q-axis control signal.

6. An inverter control device based on a virtual synchronous machine, used to implement the inverter control method based on a virtual synchronous machine as described in any one of claims 1-5, characterized in that... The device relates to a filter under test, which is connected to an inverter, and includes: The acquisition module is used to respond to inverter control requests, acquire reference data from the virtual synchronous machine, and acquire the measured voltage value of the filter under test; The reference voltage calculation module is used to calculate the reference voltage value of the inverter based on reference data. The comparison module is used to compare the reference voltage value with the measured voltage value to determine whether the measured voltage value is abnormal. The control module is used to generate a control signal for the inverter based on a preset voltage control model if the measured voltage value is abnormal. An execution module is used to control the inverter to output a voltage value corresponding to the reference data via the control signal.

7. The inverter control device based on a virtual synchronous machine according to claim 6, characterized in that, The reference data includes voltage amplitude and transformation angle, and the reference voltage calculation module includes: The first sine calculation submodule is used to calculate the first sine value of the transformed angle; The first multiplication calculation submodule is used to calculate the first multiplication value between the first sine value and the voltage amplitude. The second sine calculation submodule is used to calculate the first difference between the transformation angle and the angle threshold, and to calculate the second sine value of the first difference. The second multiplication calculation submodule is used to calculate the second multiplication value between the second sine value and the voltage amplitude. The third sine calculation submodule is used to calculate the first sum between the transformation angle and the angle threshold, and to calculate the third sine value of the first sum. The third multiplication calculation submodule is used to calculate the third multiplication value between the third sine value and the voltage amplitude. The reference voltage calculation submodule is used to determine the first multiplication value, the second multiplication value, and the third multiplication value as the reference voltage value.

8. The inverter control device based on a virtual synchronous machine according to claim 6, characterized in that, The comparison module includes: The first error rate calculation submodule is used to calculate the second difference between the reference voltage value and the measured voltage value, and to determine the ratio of the second difference to the reference voltage value as the first error rate. The first judgment submodule is used to determine whether the first error rate is greater than or equal to the voltage threshold. If the first error rate is greater than or equal to the voltage threshold, the measured voltage value is determined to be abnormal. If the first error rate is less than the voltage threshold, then the measured voltage value is determined to be normal.

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