Variable frequency transformer fault ride-through control method for adjusting harmonic distortion and related device

Abstract

The invention discloses a variable-frequency transformer fault ride-through control method for adjusting harmonic distortion and a related device, which are applied to a fault ride-through circuit and are used for acquiring a power grid voltage, a stator winding parameter, a three-phase converter parameter, a capacitor voltage and a rotor phase angle; calculating stator winding reactive power and odd harmonic direct-current components based on the acquired parameters; calculating and analyzing the parameters based on a preset voltage control equation to obtain a positive sequence voltage reference value direct-current component and an odd harmonic voltage reference value direct-current component of the three-phase converter; analyzing the two parameters according to a power grid voltage phase angle and a rotor phase angle to obtain a voltage vector reference value of the three-phase converter in the two-phase static coordinate system; and performing space vector modulation on the voltage vector reference value of the three-phase converter to generate a control signal of a three-phase converter switch so as to realize fault ride-through control. The technical problems that in the prior art, at least two three-phase converters are needed to achieve power grid harmonic distortion fault ride-through adjustment control, consumables are large, and operation is complex are solved.

Description

Technical Field

[0001] The present application relates to the field of power grid control technology, and in particular to a variable frequency transformer fault ride-through control method for regulating harmonic distortion and a related device. Background Art

[0002] The power grid is an important framework of the energy Internet, and the interconnection of power grids will be an inevitable trend in the future development of power grids. The variable frequency transformer is a new type of power grid interconnection equipment. When the power grid voltage on both sides of the variable frequency transformer is harmonically distorted, the current flowing through the variable frequency transformer will be harmonically distorted, which will cause the torque and power of the variable frequency transformer to fluctuate by six times the rotor rotation electrical angular velocity, six times the stator synchronous angular velocity, six times the rotor synchronous angular velocity, twelve times the stator synchronous angular velocity, and six times the stator synchronous angular velocity plus six times the rotor synchronous angular velocity. . The fluctuation of torque will reduce the mechanical life of the shaft, and the fluctuation of power will reduce the power quality of the power system.

[0003] The existing technology usually requires the use of at least two three-phase converters to stabilize the DC capacitor voltage and solve the problem of harmonic distortion of the grid voltage on both sides. From the perspective of consumables cost, this will undoubtedly consume more materials and be more expensive. From the perspective of the operation process, too many devices will increase the complexity of operation, reduce the actual control efficiency, and be unfavorable for application in actual scenarios. Summary of the invention

[0004] The present application provides a variable frequency transformer fault ride-through control method and related device for regulating harmonic distortion, which is used to solve the technical problems that the prior art requires at least two three-phase converters to achieve the regulation and control of grid voltage harmonic distortion fault ride-through, and has obvious technical problems of large material consumption and complex operation.

[0005] In view of this, a first aspect of the present application provides a variable frequency transformer fault ride-through control method for adjusting harmonic distortion, the control method being applied in a variable frequency transformer fault ride-through circuit, the circuit comprising: a first power grid, a second power grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a DC capacitor, and a control circuit;

[0006] One end of the AC output end of the three-phase transformer is connected to the first power grid, and the other end is connected to the stator winding of the variable frequency transformer;

[0007] The rotor winding of the variable frequency transformer is connected to the second power grid;

[0008] The AC input terminal of the three-phase transformer is connected to the AC terminal of the three-phase converter;

[0009] The DC end of the three-phase converter is connected to the DC input end of the H-bridge converter and the DC capacitor;

[0010] The DC output end of the H-bridge converter is connected to the DC motor of the variable frequency transformer;

[0011] The control circuit is connected to the control signal input terminals of the three-phase converter and the H-bridge converter respectively;

[0012] The control method comprises:

[0013] Collecting grid voltage, stator winding parameters, three-phase converter parameters, capacitor voltage and rotor phase angle, wherein the grid voltage includes the voltage of the first grid and the second grid, and the stator winding parameters and the three-phase converter parameters both include voltage and current;

[0014] Analyzing and processing the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle to obtain the stator winding reactive power, the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components;

[0015] Analyzing and processing the capacitor voltage, the stator winding reactive power, the three-phase converter positive sequence current DC component and the stator winding odd harmonic DC component based on a preset voltage control equation to obtain a three-phase converter positive sequence voltage reference value DC component and a plurality of three-phase converter odd harmonic voltage reference value DC components;

[0016] Analyzing the DC component of the positive sequence voltage reference value of the three-phase converter and the DC component of the odd harmonic voltage reference value of the three-phase converter according to the grid voltage phase angle and the rotor phase angle, to obtain a voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system;

[0017] The three-phase converter voltage vector reference value is subjected to space vector modulation to generate a control signal for the three-phase converter switch, and variable frequency transformer fault ride-through control is implemented based on the control signal.

[0018] Preferably, the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle are analyzed and processed to obtain the stator winding reactive power, the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components, including:

[0019] Performing power calculation according to the stator winding parameters to obtain the stator winding reactive power;

[0020] Phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering are performed respectively according to the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle to obtain a three-phase converter positive sequence current DC component and a plurality of stator winding odd harmonic DC components.

[0021] Preferably, the phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering are performed according to the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle to obtain the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components, including:

[0022] The grid voltage and the three-phase converter parameters are respectively subjected to phase-locked loop processing to obtain a grid voltage phase angle and a three-phase converter phase angle;

[0023] Performing three-phase stationary to two-phase rotating coordinate transformation processing on the current parameters of the three-phase converter parameters according to the voltage phase angle of the three-phase converter to obtain a DC component of the positive sequence current of the three-phase converter;

[0024] According to the grid voltage phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a first preset frequency notch filter to obtain a stator winding fifth harmonic voltage DC component and a stator winding seventh harmonic voltage DC component;

[0025] According to the grid voltage phase angle and the rotor phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a second preset frequency notch filter to obtain a stator winding fifth harmonic current DC component and a stator winding seventh harmonic current DC component.

[0026] Preferably, the analyzing the DC component of the positive sequence voltage reference value of the three-phase converter and the DC component of the odd harmonic voltage reference value of the three-phase converter according to the grid voltage phase angle and the rotor phase angle to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system includes:

[0027] According to the grid voltage phase angle, the DC component of the positive sequence voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a positive sequence voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system;

[0028] According to the grid voltage phase angle, the DC component of the odd harmonic voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a three-phase converter odd harmonic voltage vector reference value in a two-phase stationary coordinate system;

[0029] The positive sequence voltage vector reference value of the three-phase converter and the odd harmonic voltage vector reference value of the three-phase converter are summed to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system.

[0030] A second aspect of the present application provides a variable frequency transformer fault ride-through control device for adjusting harmonic distortion, the control device being applied in a variable frequency transformer fault ride-through circuit, the circuit comprising: a first power grid, a second power grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a DC capacitor and a control circuit;

[0031] One end of the AC output end of the three-phase transformer is connected to the first power grid, and the other end is connected to the stator winding of the variable frequency transformer;

[0032] The rotor winding of the variable frequency transformer is connected to the second power grid;

[0033] The AC input terminal of the three-phase transformer is connected to the AC terminal of the three-phase converter;

[0034] The DC end of the three-phase converter is connected to the DC input end of the H-bridge converter and the DC capacitor;

[0035] The DC output end of the H-bridge converter is connected to the DC motor of the variable frequency transformer;

[0036] The control circuit is connected to the control signal input terminals of the three-phase converter and the H-bridge converter respectively;

[0037] The control device comprises:

[0038] A parameter acquisition unit, used to acquire grid voltage, stator winding parameters, three-phase converter parameters, capacitor voltage and rotor phase angle, wherein the grid voltage includes the voltage of the first grid and the second grid, and the stator winding parameters and the three-phase converter parameters include voltage and current;

[0039] A first analysis unit is used to analyze and process the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle to obtain the stator winding reactive power, the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components;

[0040] A second analysis unit is used to analyze and process the capacitor voltage, the stator winding reactive power, the three-phase converter positive sequence current DC component and the stator winding odd harmonic DC component based on a preset voltage control equation to obtain a three-phase converter positive sequence voltage reference value DC component and a plurality of three-phase converter odd harmonic voltage reference value DC components;

[0041] a third analysis unit, configured to analyze the DC component of the positive sequence voltage reference value of the three-phase converter and the DC component of the odd harmonic voltage reference value of the three-phase converter according to the grid voltage phase angle and the rotor phase angle, so as to obtain a voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system;

[0042] A modulation control unit is used to perform space vector modulation on the voltage vector reference value of the three-phase converter to generate a control signal for the switch of the three-phase converter, and implement fault ride-through control of the variable frequency transformer based on the control signal.

[0043] Preferably, the first analysis unit comprises:

[0044] A power calculation subunit, used to perform power calculation according to the stator winding parameters to obtain the stator winding reactive power;

[0045] The component calculation subunit is used to perform phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering according to the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle, so as to obtain the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components.

[0046] Preferably, the component calculation subunit is specifically used for:

[0047] The grid voltage and the three-phase converter parameters are respectively subjected to phase-locked loop processing to obtain a grid voltage phase angle and a three-phase converter phase angle;

[0048] Performing three-phase stationary to two-phase rotating coordinate transformation processing on the current parameters of the three-phase converter parameters according to the voltage phase angle of the three-phase converter to obtain a DC component of the positive sequence current of the three-phase converter;

[0049] According to the grid voltage phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a first preset frequency notch filter to obtain a stator winding fifth harmonic voltage DC component and a stator winding seventh harmonic voltage DC component;

[0050] According to the grid voltage phase angle and the rotor phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a second preset frequency notch filter to obtain a stator winding fifth harmonic current DC component and a stator winding seventh harmonic current DC component.

[0051] Preferably, the third analysis unit is used for:

[0052] According to the grid voltage phase angle, the DC component of the positive sequence voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a positive sequence voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system;

[0053] According to the grid voltage phase angle, the DC component of the odd harmonic voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a three-phase converter odd harmonic voltage vector reference value in a two-phase stationary coordinate system;

[0054] The positive sequence voltage vector reference value of the three-phase converter and the odd harmonic voltage vector reference value of the three-phase converter are summed to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system.

[0055] A third aspect of the present application provides a variable frequency transformer fault ride-through control device for adjusting harmonic distortion, the device comprising a processor and a memory;

[0056] The memory is used to store program code and transmit the program code to the processor;

[0057] The processor is used to execute the variable frequency transformer fault ride-through control method for adjusting harmonic distortion described in the first aspect according to the instructions in the program code.

[0058] A fourth aspect of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store program code, and the program code is used to execute the variable frequency transformer fault ride-through control method for adjusting harmonic distortion described in the first aspect.

[0059] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0060] In the present application, a variable frequency transformer fault ride-through control method for adjusting harmonic distortion is provided. The control method is applied in a variable frequency transformer fault ride-through circuit, and the circuit includes: a first power grid, a second power grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a DC capacitor and a control circuit; one end of the AC output end of the three-phase transformer is connected to the first power grid, and the other end is connected to the stator winding of the variable frequency transformer; the rotor winding of the variable frequency transformer is connected to the second power grid; the AC input end of the three-phase transformer is connected to the AC end of the three-phase converter; the DC end of the three-phase converter is connected to the DC input end and the DC capacitor of the H-bridge converter; the DC output end of the H-bridge converter is connected to the DC motor of the variable frequency transformer; and the control circuit is respectively connected to the control signal input ends of the three-phase converter and the H-bridge converter.

[0061] Control methods include:

[0062] The grid voltage, stator winding parameters, three-phase converter parameters, capacitor voltage and rotor phase angle are collected, the grid voltage includes the voltage of the first grid and the second grid, and the stator winding parameters and the three-phase converter parameters include voltage and current; the grid voltage, stator winding parameters, three-phase converter parameters and rotor phase angle are analyzed and processed to obtain the stator winding reactive power, the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components; the capacitor voltage, stator winding reactive power, the three-phase converter positive sequence current DC component and the stator winding odd harmonic DC components are calculated based on the preset voltage control equation. The DC components of the odd harmonic voltage reference values ​​of the three-phase converter are analyzed and processed to obtain the DC components of the positive-sequence voltage reference value of the three-phase converter and the DC components of the odd harmonic voltage reference values ​​of the three-phase converter; the DC components of the positive-sequence voltage reference value of the three-phase converter and the DC components of the odd harmonic voltage reference value of the three-phase converter are analyzed according to the grid voltage phase angle and the rotor phase angle to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system; the voltage vector reference value of the three-phase converter is space-vector modulated to generate a control signal of the three-phase converter switch, and the fault ride-through control of the variable frequency transformer is realized based on the control signal.

[0063] The variable frequency transformer fault ride-through control method for regulating harmonic distortion provided by the present application is applied to the variable frequency transformer fault ride-through circuit. The fault ride-through circuit only needs to connect a three-phase converter in series to simultaneously solve the DC capacitor voltage control problem and the problem of harmonic distortion of the grid voltage on both sides; a detailed and clear fault ride-through control method is designed based on this circuit, which can still accurately calculate the control signal without relying on more three-phase converters, and while ensuring the reliability of the variable frequency transformer ride-through control, it can also reduce the circuit complexity, avoid large consumables and more complex operations, and can meet the actual fault ride-through control needs. Therefore, the present application can solve the technical problems that the prior art requires at least two three-phase converters to achieve the regulation and control of grid voltage harmonic distortion fault ride-through, and there are obvious consumables and complex operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 A schematic diagram of a control circuit structure of a variable frequency transformer fault ride-through control method for adjusting harmonic distortion provided in an embodiment of the present application;

[0065] Figure 2 A schematic flow chart of a method for controlling a variable frequency transformer fault ride-through for adjusting harmonic distortion provided in an embodiment of the present application;

[0066] Figure 3 A schematic diagram of the overall calculation and analysis process of the variable frequency transformer fault ride-through control method for adjusting harmonic distortion provided in an embodiment of the present application;

[0067] Figure 4A schematic structural diagram of a variable frequency transformer fault ride-through control device for adjusting harmonic distortion provided in an embodiment of the present application. DETAILED DESCRIPTION

[0068] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0069] For easier understanding, see Figure 1 , the present application provides an embodiment of a variable frequency transformer fault ride-through control method for adjusting harmonic distortion, the control method is applied in a variable frequency transformer fault ride-through circuit, the circuit comprising: a first power grid, a second power grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a DC capacitor and a control circuit.

[0070] One end of the AC output end of the three-phase transformer is connected to the first power grid, and the other end is connected to the stator winding of the variable frequency transformer;

[0071] The rotor winding of the variable frequency transformer is connected to the second power grid;

[0072] The AC input terminal of the three-phase transformer is connected to the AC terminal of the three-phase converter;

[0073] The DC end of the three-phase converter is connected to the DC input end of the H-bridge converter and the DC capacitor;

[0074] The DC output end of the H-bridge converter is connected to the DC motor of the variable frequency transformer;

[0075] The control circuit is connected to the control signal input terminals of the three-phase converter and the H-bridge converter respectively.

[0076] It should be noted that Figure 1 The variable frequency transformer (5) includes a stator winding (51), a rotor winding (52) and a DC motor (53); the first power grid (1) is connected to one end of the AC output end of the three-phase transformer (3). It can be found that Figure 1 The proposed variable frequency transformer fault ride-through circuit only requires a three-phase converter (4) to be connected in series to achieve fault ride-through. Compared with the prior art, the circuit design is simpler and clearer, which can reduce circuit complexity, reduce circuit design costs, and avoid complex operations caused by complex circuits.

[0077] See also Figure 2 , control methods include:

[0078] Step 101: Collect grid voltage, stator winding parameters, three-phase converter parameters, capacitor voltage and rotor phase angle. The grid voltage includes the voltage of the first grid and the second grid. The stator winding parameters and the three-phase converter parameters include voltage and current.

[0079] According to the variable frequency transformer fault ride-through circuit provided above, the voltages of the first power grid (1) and the second power grid (2) can be collected, that is, the power grid voltages can be expressed as , ; The stator winding parameters specifically include the stator winding voltage and stator winding current ; The three-phase converter parameters specifically include the three-phase converter voltage and the three-phase converter current ; The capacitor voltage is the voltage of the DC capacitor (7), expressed as ; The rotor phase angle is expressed as .

[0080] Step 102: Analyze and process the grid voltage, stator winding parameters, three-phase converter parameters and rotor phase angle to obtain stator winding reactive power, three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components.

[0081] Furthermore, step 102 includes:

[0082] Power calculation is performed according to the stator winding parameters to obtain the stator winding reactive power;

[0083] According to the grid voltage, stator winding parameters, three-phase converter parameters and rotor phase angle, phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering are performed respectively to obtain the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components.

[0084] Furthermore, according to the grid voltage, stator winding parameters, three-phase converter parameters and rotor phase angle, phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering are performed respectively to obtain the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components, including:

[0085] The grid voltage and the three-phase converter parameters are processed by phase-locked loops respectively to obtain the grid voltage phase angle and the three-phase converter phase angle;

[0086] According to the voltage phase angle of the three-phase converter, the current parameters of the three-phase converter parameters are transformed from three-phase static to two-phase rotating coordinates to obtain the DC component of the positive sequence current of the three-phase converter;

[0087] According to the grid voltage phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a first preset frequency notch filter to obtain a stator winding fifth harmonic voltage DC component and a stator winding seventh harmonic voltage DC component;

[0088] According to the grid voltage phase angle and the rotor phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a second preset frequency notch filter to obtain the stator winding fifth harmonic current DC component and the stator winding seventh harmonic current DC component.

[0089] It should be noted that according to the stator winding voltage and stator winding current The power calculation can be performed directly to obtain the reactive power of the stator winding, that is, the reactive power of the stator winding . The first grid voltage , the second grid voltage and the three-phase converter voltage Through phase-locked loop processing, the first grid voltage phase angle can be obtained , the second grid voltage phase angle and the three-phase converter voltage phase angle That is, the grid voltage phase angle includes the voltage phase angle of the first grid and the second grid. Then, according to the voltage phase angle of the three-phase converter The three-phase converter current By transforming the three-phase stationary to two-phase rotating coordinates, the DC component of the positive sequence current of the three-phase converter can be obtained. .

[0090] According to the first grid voltage phase angle The stator winding voltage can be Perform three-phase stationary to two-phase rotating coordinate transformation processing, and respectively pass through the first preset frequency and The fifth harmonic voltage DC component of the stator winding in the stator fifth harmonic synchronous rotating coordinate system is obtained by filtering the fifth harmonic voltage of the stator winding in the stator fifth harmonic synchronous rotating coordinate system. . The first grid voltage phase angle is used Stator winding voltage Perform three-phase stationary to two-phase rotating coordinate transformation processing, and respectively pass through the first preset frequency and The DC component of the seventh harmonic voltage of the stator winding in the seventh harmonic synchronous rotating coordinate system can be obtained by filtering with a notch filter. .

[0091] According to the second grid voltage phase angle and rotor phase angle Stator winding current The three-phase stationary to two-phase rotating coordinate transformation is performed, and the second preset frequency is respectively and The fifth harmonic current DC component of the stator winding in the rotor fifth harmonic synchronous rotating coordinate system is obtained by filtering the fifth harmonic current of the stator winding in the rotor fifth harmonic synchronous rotating coordinate system. According to the second grid voltage phase angle and rotor phase angle Stator winding current The three-phase stationary to two-phase rotating coordinate transformation is performed, and the second preset frequency is respectively and The trap filter is used for filtering to obtain the seventh harmonic current DC component of the stator winding in the rotor seventh harmonic synchronous rotating coordinate system. .

[0092] Step 103: Analyze and process the capacitor voltage, stator winding reactive power, three-phase converter positive sequence current DC component and stator winding odd harmonic DC component based on a preset voltage control equation to obtain a three-phase converter positive sequence voltage reference value DC component and multiple three-phase converter odd harmonic voltage reference value DC components.

[0093] The preset voltage control equation of this embodiment is:

[0094]

[0095] in, represents the Laplace operator, is the DC capacitor voltage reference value; is the stator winding reactive power reference value; and They are the d-axis component and q-axis component of the DC component of the positive sequence current reference value of the three-phase converter respectively; and They are the d-axis component and q-axis component of the DC component of the positive sequence current of the three-phase converter respectively; and They are the d-axis component and q-axis component of the DC component of the positive sequence voltage reference value of the three-phase converter respectively; and They are the d-axis component and q-axis component of the stator winding fifth harmonic voltage DC component respectively; and are respectively the d-axis component and the q-axis component of the DC component of the first and fifth harmonic voltage reference values ​​of the three-phase converter; and They are the d-axis component and q-axis component of the DC component of the seventh harmonic voltage of the stator winding respectively; and are respectively the d-axis component and the q-axis component of the DC component of the first and seventh harmonic voltage reference values ​​of the three-phase converter; and They are the d-axis component and q-axis component of the fifth harmonic current DC component of the stator winding respectively; and are the d-axis component and q-axis component of the DC component of the second and fifth harmonic voltage reference values ​​of the three-phase converter respectively; and They are the d-axis component and q-axis component of the DC component of the seventh harmonic current of the stator winding respectively; and are respectively the d-axis component and the q-axis component of the DC component of the second and seventh harmonic voltage reference values ​​of the three-phase converter; and are the proportional coefficient and integral coefficient of the DC capacitor voltage controller respectively; and They are the proportional coefficient and integral coefficient of the stator winding reactive power controller respectively; and They are the proportional coefficient and integral coefficient of the d-axis positive sequence current controller of the three-phase converter; and They are the proportional coefficient and integral coefficient of the q-axis positive sequence current controller of the three-phase converter; and They are the proportional coefficient and integral coefficient of the stator winding d-axis fifth harmonic voltage controller; and They are the proportional coefficient and integral coefficient of the stator winding q-axis fifth harmonic voltage controller; and They are the proportional coefficient and integral coefficient of the stator winding d-axis seventh harmonic voltage controller; and They are the proportional coefficient and integral coefficient of the q-axis seventh harmonic voltage controller of the stator winding; and They are the proportional coefficient and integral coefficient of the stator winding d-axis fifth harmonic current controller; and They are the proportional coefficient and integral coefficient of the stator winding q-axis fifth harmonic current controller; and They are the proportional coefficient and integral coefficient of the stator winding d-axis seventh harmonic current controller; and They are the proportional coefficient and integral coefficient of the q-axis seventh harmonic current controller of the stator winding respectively.

[0096] Based on the preset voltage control equation, the capacitor voltage , stator winding reactive power , DC component of positive sequence current of three-phase converter and all stator winding odd harmonic DC components , , , By analyzing and processing, the DC component of the positive sequence voltage reference value of the three-phase converter can be obtained. and a plurality of three-phase converter odd harmonic voltage reference value DC components. Among them, the three-phase converter odd harmonic voltage reference value DC components include the first and fifth harmonic voltage reference value DC components of the three-phase converter , DC component of the first and seventh harmonic voltage reference values ​​of the three-phase converter , DC component of the second and fifth harmonic voltage reference values ​​of three-phase converters The DC component of the second and seventh harmonic voltage reference values ​​of the three-phase converter .

[0097] Step 104: Analyze the DC component of the three-phase converter positive sequence voltage reference value and the DC component of the three-phase converter odd harmonic voltage reference value according to the grid voltage phase angle and the rotor phase angle to obtain the three-phase converter voltage vector reference value in the two-phase stationary coordinate system.

[0098] Furthermore, step 104 includes:

[0099] According to the grid voltage phase angle, the DC component of the positive sequence voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a positive sequence voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system;

[0100] According to the grid voltage phase angle, the DC component of the odd harmonic voltage reference value of the three-phase converter is transformed from a two-phase rotation to a two-phase stationary coordinate system to obtain the odd harmonic voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system;

[0101] The positive sequence voltage vector reference value of the three-phase converter and the odd harmonic voltage vector reference value of the three-phase converter are summed to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system.

[0102] It should be noted that, according to the first grid voltage phase angle The DC component of the positive sequence voltage reference value of the three-phase converter The positive sequence voltage vector reference value of the three-phase converter in the two-phase stationary coordinate system can be obtained by performing a two-phase rotating to two-phase stationary coordinate transformation. .

[0103] According to the first grid voltage phase angle The DC components of the first and fifth harmonic voltage reference values ​​of the three-phase converter are , DC component of the first and seventh harmonic voltage reference values ​​of the three-phase converter By performing a two-phase rotation to two-phase stationary coordinate transformation process, the corresponding three-phase converter odd harmonic voltage vector reference value in the two-phase stationary coordinate system can be obtained; specifically, the first and fifth harmonic voltage vector reference values ​​of the three-phase converter And the first and seventh harmonic voltage vector reference values ​​of the three-phase converter .

[0104] According to the second grid voltage phase angle and rotor phase angle The DC components of the second and fifth harmonic voltage reference values ​​of the three-phase converter are The DC component of the second and seventh harmonic voltage reference values ​​of the three-phase converter By performing a two-phase rotating to two-phase stationary coordinate transformation process, the corresponding odd harmonic voltage vector reference value of the three-phase converter can be obtained; specifically, the second and fifth harmonic voltage vector reference values ​​of the three-phase converter are obtained. And the second and seventh harmonic voltage vector reference values ​​of the three-phase converter .

[0105] The positive sequence voltage vector reference value of the three-phase converter calculated above is , three-phase converter first and fifth harmonic voltage vector reference value , three-phase converter first and seventh harmonic voltage vector reference value , the second and fifth harmonic voltage vector reference values ​​of three-phase converter And the second and seventh harmonic voltage vector reference values ​​of the three-phase converter The sum is calculated to obtain the voltage vector reference value of the three-phase converter in the two-phase stationary coordinate system. .

[0106] Step 105: Perform space vector modulation on the voltage vector reference value of the three-phase converter to generate a control signal for the switch of the three-phase converter, and implement variable frequency transformer fault ride-through control based on the control signal.

[0107] For the overall calculation and analysis process of the variable frequency transformer fault ride-through control of this embodiment, please refer to Figure 3 , the calculated three-phase converter voltage vector reference value The control signal of the three-phase converter switch can be obtained through space vector modulation SVPWM , , ; Based on the control signal, the fault ride-through control of the variable frequency transformer can be realized.

[0108] The variable frequency transformer fault ride-through control method for regulating harmonic distortion provided by the present application is applied to the variable frequency transformer fault ride-through circuit. The fault ride-through circuit only needs to connect a three-phase converter in series to simultaneously solve the DC capacitor voltage control problem and the problem of harmonic distortion of the grid voltage on both sides; a detailed and clear fault ride-through control method is designed based on this circuit, which can still accurately calculate the control signal without relying on more three-phase converters, and while ensuring the reliability of the variable frequency transformer ride-through control, it can also reduce the circuit complexity, avoid large consumables and more complex operations, and can meet the actual fault ride-through control needs. Therefore, the present application can solve the technical problems that the prior art requires at least two three-phase converters to achieve the regulation and control of grid voltage harmonic distortion fault ride-through, and there are obvious consumables and complex operations.

[0109] For easier understanding, see Figure 4 , the present application provides an embodiment of a variable frequency transformer fault ride-through control device for adjusting harmonic distortion, the control device is applied in a variable frequency transformer fault ride-through circuit, the circuit comprising: a first power grid, a second power grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a DC capacitor and a control circuit;

[0110] One end of the AC output end of the three-phase transformer is connected to the first power grid, and the other end is connected to the stator winding of the variable frequency transformer;

[0111] The rotor winding of the variable frequency transformer is connected to the second power grid;

[0112] The AC input terminal of the three-phase transformer is connected to the AC terminal of the three-phase converter;

[0113] The DC end of the three-phase converter is connected to the DC input end of the H-bridge converter and the DC capacitor;

[0114] The DC output end of the H-bridge converter is connected to the DC motor of the variable frequency transformer;

[0115] The control circuit is connected to the control signal input terminals of the three-phase converter and the H-bridge converter respectively;

[0116] The control device includes:

[0117] The parameter acquisition unit 201 is used to acquire the grid voltage, stator winding parameters, three-phase converter parameters, capacitor voltage and rotor phase angle, the grid voltage includes the voltage of the first grid and the second grid, and the stator winding parameters and the three-phase converter parameters include voltage and current;

[0118] The first analysis unit 202 is used to analyze and process the grid voltage, stator winding parameters, three-phase converter parameters and rotor phase angle to obtain the stator winding reactive power, the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components;

[0119] The second analysis unit 203 is used to analyze and process the capacitor voltage, the stator winding reactive power, the three-phase converter positive sequence current DC component and the stator winding odd harmonic DC component based on a preset voltage control equation to obtain a three-phase converter positive sequence voltage reference value DC component and a plurality of three-phase converter odd harmonic voltage reference value DC components;

[0120] The third analysis unit 204 is used to analyze the DC component of the positive sequence voltage reference value of the three-phase converter and the DC component of the odd harmonic voltage reference value of the three-phase converter according to the grid voltage phase angle and the rotor phase angle to obtain the voltage vector reference value of the three-phase converter in the two-phase stationary coordinate system;

[0121] The modulation control unit 205 is used to perform space vector modulation on the voltage vector reference value of the three-phase converter, generate a control signal for the three-phase converter switch, and implement fault ride-through control of the variable frequency transformer based on the control signal.

[0122] Furthermore, the first analysis unit 202 includes:

[0123] The power calculation subunit 2021 is used to perform power calculation according to the stator winding parameters to obtain the stator winding reactive power;

[0124] The component calculation subunit 2022 is used to perform phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering according to the grid voltage, stator winding parameters, three-phase converter parameters and rotor phase angle, so as to obtain the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components.

[0125] Furthermore, the component calculation subunit 2022 is specifically used for:

[0126] The grid voltage and the three-phase converter parameters are processed by phase-locked loops respectively to obtain the grid voltage phase angle and the three-phase converter phase angle;

[0127] According to the voltage phase angle of the three-phase converter, the current parameters of the three-phase converter parameters are transformed from three-phase static to two-phase rotating coordinates to obtain the DC component of the positive sequence current of the three-phase converter;

[0128] According to the grid voltage phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a first preset frequency notch filter to obtain a stator winding fifth harmonic voltage DC component and a stator winding seventh harmonic voltage DC component;

[0129] According to the grid voltage phase angle and the rotor phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a second preset frequency notch filter to obtain the stator winding fifth harmonic current DC component and the stator winding seventh harmonic current DC component.

[0130] Further, the third analysis unit 204 is used to:

[0131] According to the grid voltage phase angle, the DC component of the positive sequence voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a positive sequence voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system;

[0132] According to the grid voltage phase angle, the DC component of the odd harmonic voltage reference value of the three-phase converter is transformed from a two-phase rotation to a two-phase stationary coordinate system to obtain the odd harmonic voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system;

[0133] The positive sequence voltage vector reference value of the three-phase converter and the odd harmonic voltage vector reference value of the three-phase converter are summed to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system.

[0134] The present application also provides a variable frequency transformer fault ride-through control device for adjusting harmonic distortion, the device comprising a processor and a memory;

[0135] The memory is used to store the program code and transmit the program code to the processor;

[0136] The processor is used to execute the variable frequency transformer fault ride-through control method for adjusting harmonic distortion in the above method embodiment according to the instructions in the program code.

[0137] The present application also provides a computer-readable storage medium, which is used to store program code, and the program code is used to execute the variable frequency transformer fault ride-through control method for adjusting harmonic distortion in the above method embodiment.

[0138] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0139] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0140] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0141] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a number of instructions for executing all or part of the steps of the method described in each embodiment of the present application through a computer device (which can be a personal computer, server, or network device, etc.). The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store program codes.

[0142] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A variable frequency transformer fault ride-through control method for adjusting harmonic distortion, characterized in that: The control method is applied in a variable frequency transformer fault ride-through circuit, the circuit comprising: a first power grid, a second power grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a DC capacitor and a control circuit; One end of the AC output end of the three-phase transformer is connected to the first power grid, and the other end is connected to the stator winding of the variable frequency transformer; The rotor winding of the variable frequency transformer is connected to the second power grid; The AC input terminal of the three-phase transformer is connected to the AC terminal of the three-phase converter; The DC end of the three-phase converter is connected to the DC input end of the H-bridge converter and the DC capacitor; The DC output end of the H-bridge converter is connected to the DC motor of the variable frequency transformer; The control circuit is connected to the control signal input terminals of the three-phase converter and the H-bridge converter respectively; The control method comprises: Collecting grid voltage, stator winding parameters, three-phase converter parameters, capacitor voltage and rotor phase angle, wherein the grid voltage includes the voltage of the first grid and the second grid, and the stator winding parameters and the three-phase converter parameters both include voltage and current; Analyzing and processing the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle to obtain the stator winding reactive power, the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components; Analyzing and processing the capacitor voltage, the stator winding reactive power, the three-phase converter positive sequence current DC component and the stator winding odd harmonic DC component based on a preset voltage control equation to obtain a three-phase converter positive sequence voltage reference value DC component and a plurality of three-phase converter odd harmonic voltage reference value DC components; Analyzing the DC component of the positive sequence voltage reference value of the three-phase converter and the DC component of the odd harmonic voltage reference value of the three-phase converter according to the grid voltage phase angle and the rotor phase angle, to obtain a voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system; The three-phase converter voltage vector reference value is subjected to space vector modulation to generate a control signal for the three-phase converter switch, and variable frequency transformer fault ride-through control is implemented based on the control signal.

2. The variable frequency transformer fault ride-through control method for adjusting harmonic distortion according to claim 1, characterized in that: The grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle are analyzed and processed to obtain the stator winding reactive power, the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components, including: Performing power calculation according to the stator winding parameters to obtain the stator winding reactive power; Phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering are performed respectively according to the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle to obtain a three-phase converter positive sequence current DC component and a plurality of stator winding odd harmonic DC components.

3. The variable frequency transformer fault ride-through control method for adjusting harmonic distortion according to claim 2 is characterized in that: The phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering are performed according to the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle to obtain the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components, including: The grid voltage and the three-phase converter parameters are respectively subjected to phase-locked loop processing to obtain a grid voltage phase angle and a three-phase converter phase angle; Performing three-phase stationary to two-phase rotating coordinate transformation processing on the current parameters of the three-phase converter parameters according to the voltage phase angle of the three-phase converter to obtain a DC component of the positive sequence current of the three-phase converter; According to the grid voltage phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a first preset frequency notch filter to obtain a stator winding fifth harmonic voltage DC component and a stator winding seventh harmonic voltage DC component; According to the grid voltage phase angle and the rotor phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a second preset frequency notch filter to obtain a stator winding fifth harmonic current DC component and a stator winding seventh harmonic current DC component.

4. The variable frequency transformer fault ride-through control method for adjusting harmonic distortion according to claim 1, characterized in that: The analyzing the DC component of the positive sequence voltage reference value of the three-phase converter and the DC component of the odd harmonic voltage reference value of the three-phase converter according to the grid voltage phase angle and the rotor phase angle to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system includes: According to the grid voltage phase angle, the DC component of the positive sequence voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a positive sequence voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system; According to the grid voltage phase angle, the DC component of the odd harmonic voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a three-phase converter odd harmonic voltage vector reference value in a two-phase stationary coordinate system; The positive sequence voltage vector reference value of the three-phase converter and the odd harmonic voltage vector reference value of the three-phase converter are summed to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system.

5. A variable frequency transformer fault ride-through control device for adjusting harmonic distortion, characterized in that: The control device is applied in a variable frequency transformer fault ride-through circuit, the circuit comprising: a first power grid, a second power grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a DC capacitor and a control circuit; One end of the AC output end of the three-phase transformer is connected to the first power grid, and the other end is connected to the stator winding of the variable frequency transformer; The rotor winding of the variable frequency transformer is connected to the second power grid; The AC input terminal of the three-phase transformer is connected to the AC terminal of the three-phase converter; The DC end of the three-phase converter is connected to the DC input end of the H-bridge converter and the DC capacitor; The DC output end of the H-bridge converter is connected to the DC motor of the variable frequency transformer; The control circuit is connected to the control signal input terminals of the three-phase converter and the H-bridge converter respectively; The control device comprises: A parameter acquisition unit, used to acquire grid voltage, stator winding parameters, three-phase converter parameters, capacitor voltage and rotor phase angle, wherein the grid voltage includes the voltage of the first grid and the second grid, and the stator winding parameters and the three-phase converter parameters include voltage and current; A first analysis unit is used to analyze and process the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle to obtain the stator winding reactive power, the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components; A second analysis unit is used to analyze and process the capacitor voltage, the stator winding reactive power, the three-phase converter positive sequence current DC component and the stator winding odd harmonic DC component based on a preset voltage control equation to obtain a three-phase converter positive sequence voltage reference value DC component and a plurality of three-phase converter odd harmonic voltage reference value DC components; a third analysis unit, configured to analyze the DC component of the positive sequence voltage reference value of the three-phase converter and the DC component of the odd harmonic voltage reference value of the three-phase converter according to the grid voltage phase angle and the rotor phase angle, so as to obtain a voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system; A modulation control unit is used to perform space vector modulation on the voltage vector reference value of the three-phase converter to generate a control signal for the switch of the three-phase converter, and implement fault ride-through control of the variable frequency transformer based on the control signal.

6. The variable frequency transformer fault ride-through control device for adjusting harmonic distortion according to claim 5, characterized in that: The first analysis unit comprises: A power calculation subunit, used to perform power calculation according to the stator winding parameters to obtain the stator winding reactive power; The component calculation subunit is used to perform phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering according to the grid voltage, the stator winding parameters, the three-phase converter parameters and the rotor phase angle, so as to obtain the three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components.

7. The variable frequency transformer fault ride-through control device for adjusting harmonic distortion according to claim 6, characterized in that: The component calculation subunit is specifically used for: The grid voltage and the three-phase converter parameters are respectively subjected to phase-locked loop processing to obtain a grid voltage phase angle and a three-phase converter phase angle; Performing three-phase stationary to two-phase rotating coordinate transformation processing on the current parameters of the three-phase converter parameters according to the voltage phase angle of the three-phase converter to obtain a DC component of the positive sequence current of the three-phase converter; According to the grid voltage phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a first preset frequency notch filter to obtain a stator winding fifth harmonic voltage DC component and a stator winding seventh harmonic voltage DC component; According to the grid voltage phase angle and the rotor phase angle, the stator winding parameters are sequentially transformed from three-phase static to two-phase rotating coordinates and filtered by a second preset frequency notch filter to obtain a stator winding fifth harmonic current DC component and a stator winding seventh harmonic current DC component.

8. The variable frequency transformer fault ride-through control device for adjusting harmonic distortion according to claim 5, characterized in that: The third analysis unit is used for: According to the grid voltage phase angle, the DC component of the positive sequence voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a positive sequence voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system; According to the grid voltage phase angle, the DC component of the odd harmonic voltage reference value of the three-phase converter is subjected to a two-phase rotation to a two-phase stationary coordinate transformation process to obtain a three-phase converter odd harmonic voltage vector reference value in a two-phase stationary coordinate system; The positive sequence voltage vector reference value of the three-phase converter and the odd harmonic voltage vector reference value of the three-phase converter are summed to obtain the voltage vector reference value of the three-phase converter in a two-phase stationary coordinate system.

9. A variable frequency transformer fault ride-through control device for adjusting harmonic distortion, characterized in that: The device comprises a processor and a memory; The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the variable frequency transformer fault ride-through control method for adjusting harmonic distortion as described in any one of claims 1-4 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store program codes, and the program codes are used to execute the variable frequency transformer fault ride-through control method for adjusting harmonic distortion as described in any one of claims 1-4.

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