A variable frequency transformer fault ride-through control method for adjusting harmonic distortion and related devices

Abstract

The application discloses a variable-frequency transformer fault ride-through control method for adjusting harmonic distortion and related devices, which are applied to a fault ride-through circuit, collects power grid voltage, stator winding parameters, three-phase converter parameters, capacitor voltage and rotor phase angle; based on the collected parameters, the stator winding reactive power and the odd harmonic DC component are calculated; based on the preset voltage control equation, the above parameters are calculated and analyzed to obtain the positive sequence voltage reference value DC component and the odd harmonic voltage reference value DC component of the three-phase converter; according to the power grid voltage phase angle and the rotor phase angle, the two parameters are analyzed to obtain the three-phase converter voltage vector reference value in the two-phase stationary coordinate system; the three-phase converter voltage vector reference value is subjected to space vector modulation to generate the control signal of the three-phase converter switch, and the fault ride-through control is realized. The prior art needs at least two three-phase converters to realize the power grid harmonic distortion fault ride-through regulation control, and the technical problems of large material consumption and complex operation exist.

Description

TECHNICAL FIELD

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

[0002] The power grid is an important framework of the energy internet, and power grid interconnection will be an inevitable trend in the future development of the power grid. The variable-frequency transformer is a new type of power grid interconnection equipment. When the voltage of the two sides of the variable-frequency transformer is harmonically distorted, the current flowing through the variable-frequency transformer will be harmonically distorted, thereby causing the torque and power of the variable-frequency transformer to fluctuate at six times the rotational electric angular velocity of the rotor, six times the synchronous angular velocity of the stator, six times the synchronous angular velocity of the rotor, twelve times the synchronous angular velocity of the stator, and six times the synchronous angular velocity of the stator plus six times the synchronous angular velocity of the rotor. The fluctuation of the torque reduces the mechanical life of the shaft, and the fluctuation of the power reduces the power quality of the power system.

[0003] The prior art usually needs to use at least two three-phase converters to stabilize the DC capacitor voltage and solve the problem of harmonic distortion of the voltage of the two sides of the power grid. From the cost of materials, this undoubtedly consumes more materials and has higher costs; from the operation process, too many devices increase the operation complexity and reduce the actual control efficiency, which is not conducive to the application in actual scenarios. SUMMARY

[0004] The present application provides a variable-frequency transformer fault ride-through control method for adjusting harmonic distortion and a related device, which is used to solve the technical problems of obvious material consumption and operation complexity in the prior art that at least two three-phase converters are needed to realize the adjustment control of the harmonic distortion fault ride-through of the power grid voltage.

[0005] Therefore, the first aspect of the present application provides a variable-frequency transformer fault ride-through control method for adjusting harmonic distortion, which is applied in a variable-frequency transformer fault ride-through circuit. 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.

[0006] One end of an alternating current output end of the three-phase transformer is connected with the first power grid, and the other end is connected with a stator winding of the variable-frequency transformer.

[0007] A rotor winding of the variable-frequency transformer is connected with the second power grid.

[0008] An alternating current input end of the three-phase transformer is connected with an alternating current end of the three-phase converter.

[0009] A direct current end of the three-phase converter is connected with a direct current input end of the H-bridge converter and the DC capacitor.

[0010] The direct current output end of the H-bridge converter is connected with the direct current motor of the variable frequency transformer;

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

[0012] The control method comprises:

[0013] The grid voltage, the stator winding parameter, the three-phase converter parameter, the capacitor voltage and the rotor phase angle are collected, the grid voltage comprises the voltages of the first grid and the second grid, and the stator winding parameter and the three-phase converter parameter each comprise voltage and current;

[0014] The grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle are analyzed and processed to obtain the stator winding reactive power, the three-phase converter positive sequence current direct current component and a plurality of stator winding odd harmonic direct current components;

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

[0016] The three-phase converter positive sequence voltage reference value direct current component and the three-phase converter odd harmonic voltage reference value direct current component are analyzed according to the grid voltage phase angle and the rotor phase angle to obtain a three-phase converter voltage vector reference value in a two-phase stationary coordinate system;

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

[0018] Preferably, the analyzing and processing of the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle to obtain the stator winding reactive power, the three-phase converter positive sequence current direct current component and a plurality of stator winding odd harmonic direct current components comprises:

[0019] The stator winding reactive power is obtained by power calculation according to the stator winding parameter;

[0020] The three-phase converter positive sequence current direct current component and a plurality of stator winding odd harmonic direct current components are obtained by phase-locked loop processing, three-phase stationary to two-phase rotating coordinate transformation and wave trap filter processing according to the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle respectively.

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

[0022] The phase-locked loop processing is performed on the grid voltage and the three-phase converter parameters, respectively, to obtain the grid voltage phase angle and the three-phase converter phase angle;

[0023] The three-phase static to two-phase rotating coordinate transformation is performed on the current parameters of the three-phase converter parameters according to the three-phase converter voltage phase angle, to obtain the three-phase converter positive sequence current DC component;

[0024] The three-phase static to two-phase rotating coordinate transformation and the first preset frequency notch filter processing are sequentially performed on the stator winding parameters according to the grid voltage phase angle, to obtain the stator winding five times harmonic voltage DC component and the stator winding seven times harmonic voltage DC component;

[0025] The three-phase static to two-phase rotating coordinate transformation and the second preset frequency notch filter processing are sequentially performed on the stator winding parameters according to the grid voltage phase angle and the rotor phase angle, to obtain the stator winding five times harmonic current DC component and the stator winding seven times harmonic current DC component.

[0026] Preferably, the analysis is performed on the three-phase converter positive sequence voltage reference value DC component and the three-phase converter odd harmonic voltage reference value DC component 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 static coordinate system, including:

[0027] The two-phase rotating to two-phase static coordinate transformation is performed on the three-phase converter positive sequence voltage reference value DC component according to the grid voltage phase angle, to obtain the three-phase converter positive sequence voltage vector reference value in the two-phase static coordinate system;

[0028] The two-phase rotating to two-phase static coordinate transformation is performed on the three-phase converter odd harmonic voltage reference value DC component according to the grid voltage phase angle, to obtain the three-phase converter odd harmonic voltage vector reference value in the two-phase static coordinate system;

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

[0030] The second aspect of the application provides a variable frequency transformer fault ride-through control device for adjusting harmonic distortion, which is applied in a variable frequency transformer fault ride-through circuit, and the circuit comprises 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 direct current capacitor and a control circuit.

[0031] One end of an alternating current output end of the three-phase transformer is connected with the first power grid, and the other end is connected with a stator winding of the variable frequency transformer.

[0032] A rotor winding of the variable frequency transformer is connected with the second power grid.

[0033] An alternating current input end of the three-phase transformer is connected with an alternating current end of the three-phase converter.

[0034] A direct current end of the three-phase converter is connected with a direct current input end of the H-bridge converter and the direct current capacitor.

[0035] A direct current output end of the H-bridge converter is connected with a direct current motor of the variable frequency transformer.

[0036] The control circuit is connected with control signal input ends of the three-phase converter and the H-bridge converter respectively.

[0037] The control device comprises:

[0038] A parameter acquisition unit is configured to acquire power grid voltages, stator winding parameters, three-phase converter parameters, capacitor voltages and rotor phase angles, wherein the power grid voltages include voltages of the first power grid and the second power grid, and the stator winding parameters and the three-phase converter parameters each include voltages and currents.

[0039] A first analysis unit is configured to analyze and process the power grid voltages, the stator winding parameters, the three-phase converter parameters and the rotor phase angles to obtain stator winding reactive power, three-phase converter positive sequence current direct current components and a plurality of stator winding odd harmonic direct current components.

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

[0041] A third analysis unit is configured to analyze the three-phase converter positive sequence voltage reference value direct current components and the three-phase converter odd harmonic voltage reference value direct current components based on power grid voltage phase angles and the rotor phase angles to obtain three-phase converter voltage vector reference values in a two-phase stationary coordinate system.

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

[0043] Preferably, the first analysis unit comprises:

[0044] a power calculation sub-unit, configured to perform power calculation according to the stator winding parameter, to obtain stator winding reactive power;

[0045] a component calculation sub-unit, configured to perform phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering processing on the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle respectively, to obtain three-phase converter positive sequence current DC component and a plurality of stator winding odd harmonic DC components.

[0046] Preferably, the component calculation sub-unit is specifically configured to:

[0047] perform phase-locked loop processing on the grid voltage and the three-phase converter parameter respectively, to obtain grid voltage phase angle and three-phase converter phase angle;

[0048] perform three-phase static to two-phase rotating coordinate transformation processing on the current parameter of the three-phase converter parameter according to the three-phase converter voltage phase angle, to obtain three-phase converter positive sequence current DC component;

[0049] perform three-phase static to two-phase rotating coordinate transformation and first preset frequency notch filter filtering processing on the stator winding parameter according to the grid voltage phase angle, to obtain stator winding five times harmonic voltage DC component and stator winding seven times harmonic voltage DC component;

[0050] perform three-phase static to two-phase rotating coordinate transformation and second preset frequency notch filter filtering processing on the stator winding parameter according to the grid voltage phase angle and the rotor phase angle, to obtain stator winding five times harmonic current DC component and stator winding seven times harmonic current DC component.

[0051] Preferably, the third analysis unit is configured to:

[0052] perform two-phase rotating to two-phase static coordinate transformation processing on the three-phase converter positive sequence voltage reference value DC component according to grid voltage phase angle, to obtain three-phase converter positive sequence voltage vector reference value in two-phase static coordinate system;

[0053] The three-phase converter odd harmonic voltage reference value in the two-phase stationary coordinate system is obtained by performing two-phase rotation to two-phase stationary coordinate transformation on the three-phase converter odd harmonic voltage reference value according to the phase angle of the grid voltage.

[0054] The three-phase converter voltage vector reference value in the two-phase stationary coordinate system is obtained by summing the three-phase converter positive sequence voltage vector reference value and the three-phase converter odd harmonic voltage vector reference value.

[0055] The 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 configured to store program code and transmit the program code to the processor.

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

[0058] The fourth aspect of the present application provides a computer readable storage medium for storing program code, the program code being used to execute the method for adjusting harmonic distortion of the variable frequency transformer fault ride-through control.

[0059] From the above technical solutions, the embodiments of the present application have the following advantages:

[0060] In the present application, a method for adjusting harmonic distortion of a variable frequency transformer fault ride-through control is provided, which is applied in a variable frequency transformer fault ride-through circuit, the circuit comprising a first grid, a second grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a direct current capacitor and a control circuit. One end of the alternating current output end of the three-phase transformer is connected with the first grid, and the other end is connected with the stator winding of the variable frequency transformer. The rotor winding of the variable frequency transformer is connected with the second grid. The alternating current input end of the three-phase transformer is connected with the alternating current end of the three-phase converter. The direct current end of the three-phase converter is connected with the direct current input end of the H-bridge converter and the direct current capacitor. The direct current output end of the H-bridge converter is connected with the direct current motor of the variable frequency transformer. The control circuit is connected with the control signal input ends of the three-phase converter and the H-bridge converter respectively.

[0061] The control method comprises:

[0062] The grid voltage, stator winding parameter, three-phase converter parameter, capacitor voltage and rotor phase angle are collected, the grid voltage includes the voltage of the first grid and the second grid, the stator winding parameter and the three-phase converter parameter both include voltage and current; the grid voltage, stator winding parameter, three-phase converter parameter and rotor phase angle are analyzed and processed to obtain stator winding reactive power, three-phase converter positive sequence current direct current component and multiple stator winding odd harmonic direct current components; the capacitor voltage, stator winding reactive power, three-phase converter positive sequence current direct current component and stator winding odd harmonic direct current component are analyzed and processed based on a preset voltage control equation to obtain three-phase converter positive sequence voltage reference value direct current component and multiple three-phase converter odd harmonic voltage reference value direct current components; the three-phase converter positive sequence voltage reference value direct current component and the three-phase converter odd harmonic voltage reference value direct current component are analyzed according to the grid voltage phase angle and the rotor phase angle to obtain a three-phase converter voltage vector reference value 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 of the three-phase converter switch, and the control signal is used to realize the fault ride-through control of the variable frequency transformer.

[0063] The variable frequency transformer fault ride-through control method for adjusting harmonic distortion provided by the application is applied to a variable frequency transformer fault ride-through circuit. The fault ride-through circuit only needs to be connected in series with a three-phase converter to simultaneously solve the problems of DC capacitor voltage control and grid voltage harmonic distortion on both sides. A detailed and explicit fault ride-through control method is designed based on the circuit. The control signal can be accurately calculated without relying on more three-phase converters. The circuit complexity is reduced, large materials and complex operations are avoided, and the actual fault ride-through control requirements can be met. Therefore, the application can solve the technical problems of existing technology, i.e., at least two three-phase converters are needed to realize the adjustment and control of grid voltage harmonic distortion fault ride-through, which is obviously large in material consumption and complex in operation. BRIEF DESCRIPTION OF DRAWINGS

[0064] Figure 1 A control circuit structure schematic diagram of the variable frequency transformer fault ride-through control method for adjusting harmonic distortion provided by the embodiment of the application is provided.

[0065] Figure 2 A flowchart schematic diagram of the variable frequency transformer fault ride-through control method for adjusting harmonic distortion provided by the embodiment of the application is provided.

[0066] Figure 3 A whole calculation and analysis process schematic diagram of the variable frequency transformer fault ride-through control method for adjusting harmonic distortion provided by the embodiment of the application is provided.

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

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

[0069] For the convenience of understanding, please refer to Figure 1 The embodiments of the present application provide a control method for adjusting harmonic distortion of a variable frequency transformer fault ride-through. The control method is applied to a variable frequency transformer fault ride-through circuit, which comprises 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 direct current capacitor and a control circuit.

[0070] One end of an alternating current output end of the three-phase transformer is connected with the first power grid, and the other end is connected with a stator winding of the variable frequency transformer;

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

[0072] An alternating current input end of the three-phase transformer is connected with an alternating current end of the three-phase converter;

[0073] A direct current end of the three-phase converter is connected with a direct current input end of the H-bridge converter and the direct current capacitor;

[0074] A direct current output end of the H-bridge converter is connected with a direct current motor of the variable frequency transformer;

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

[0076] It should be noted that, Figure 1 The variable frequency transformer (5) in the present application comprises a stator winding (51), a rotor winding (52) and a direct current motor (53); one end of an alternating current output end of the three-phase transformer (3) is connected with the first power grid (1). It can be found that, Figure 1 The variable frequency transformer fault ride-through circuit proposed only needs to be connected with a three-phase converter (4) to realize fault ride-through. Compared with the prior art, the circuit design is more simple and clear, the circuit complexity can be reduced, the circuit design cost can be reduced, and complex operation caused by complex circuit can also be avoided.

[0077] Please refer to Figure 2 The control method comprises:

[0078] Step 101, collect grid voltage, stator winding parameter, three-phase converter parameter, capacitor voltage and rotor phase angle, the grid voltage includes the voltage of the first grid and the second grid, the stator winding parameter and the three-phase converter parameter both include voltage and current.

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

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

[0081] Further, step 102 includes:

[0082] According to the stator winding parameter, the stator winding reactive power is calculated;

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

[0084] Further, according to the grid voltage, stator winding parameter, three-phase converter parameter and rotor phase angle, phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and wave trap filter processing 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 parameter are respectively subjected to phase-locked loop processing to obtain the grid voltage phase angle and the three-phase converter phase angle;

[0086] According to the three-phase converter voltage phase angle, the current parameter of the three-phase converter parameter is subjected to three-phase static to two-phase rotating coordinate transformation processing to obtain the three-phase converter positive sequence current DC component;

[0087] According to the grid voltage phase angle, the stator winding parameters are sequentially subjected to three-phase static to two-phase rotating coordinate transformation and first preset frequency trap filter processing, to obtain the stator winding fifth harmonic voltage DC component and the 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 subjected to three-phase static to two-phase rotating coordinate transformation and second preset frequency trap filter processing, 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 the stator winding current , the power calculation can be directly performed to obtain the reactive power of the stator winding, i.e., the stator winding reactive power . And the first grid voltage , the second grid voltage and the three-phase converter voltage are subjected to phase-locked loop processing, respectively, to obtain the first grid voltage phase angle , 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 angles of the first grid and the second grid. Then, according to the three-phase converter voltage phase angle , the three-phase static to two-phase rotating coordinate transformation processing can be performed on the three-phase converter current , to obtain the three-phase converter positive sequence current DC component .

[0090] According to the first grid voltage phase angle , the stator winding voltage is subjected to three-phase static to two-phase rotating coordinate transformation processing, and is subjected to filter processing through the first preset frequency trap filter and , respectively, to obtain the stator winding fifth harmonic voltage DC component in the stator five harmonic synchronous rotating coordinate system . And according to the first grid voltage phase angle , the stator winding voltage is subjected to three-phase static to two-phase rotating coordinate transformation processing, and is subjected to filter processing through the first preset frequency trap filter and , respectively, to obtain the stator winding seventh harmonic voltage DC component in the stator seven harmonic synchronous rotating coordinate system .

[0091] According to the second grid voltage phase angle and the rotor phase angle , the stator winding current The three-phase static-to-two-phase rotating coordinate transformation process is performed, and the filtered processing is performed through the notch filter with the second preset frequency of and to obtain the stator winding fifth harmonic current direct current component in the rotor fifth harmonic synchronous rotating coordinate system . According to the second power grid voltage phase angle and the rotor phase angle , the three-phase static-to-two-phase rotating coordinate transformation process is performed on the stator winding current , and the filtered processing is performed through the notch filter with the second preset frequency of and to obtain the stator winding seventh harmonic current direct current component in the rotor seventh harmonic synchronous rotating coordinate system .

[0092] In step 103, the capacitor voltage, the stator winding reactive power, the three-phase converter positive sequence current direct current component, and the stator winding odd harmonic direct current component are analyzed and processed based on the preset voltage control equation to obtain the three-phase converter positive sequence voltage reference value direct current component and a plurality of three-phase converter odd harmonic voltage reference value direct current components.

[0093] The preset voltage control equation of the embodiment is as follows:

[0094]

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

[0096] capacitor voltage , stator winding reactive power Direct current component of positive sequence voltage reference value of three-phase converter and all stator winding odd harmonic direct current component 、 、 、 Direct current component of positive sequence voltage reference value of three-phase converter and multiple direct current components of odd harmonic voltage reference value of three-phase converter. The direct current components of odd harmonic voltage reference value of three-phase converter include direct current component of first fifth harmonic voltage reference value of three-phase converter direct current component of first seventh harmonic voltage reference value of three-phase converter direct current component of second fifth harmonic voltage reference value of three-phase converter and direct current component of second seventh harmonic voltage reference value of three-phase converter .

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

[0098] Further, step 104 includes:

[0099] According to the grid voltage phase angle, performing two-phase rotation to two-phase stationary coordinate transformation processing on the direct current component of positive sequence voltage reference value of three-phase converter, to obtain the three-phase converter positive sequence voltage vector reference value in two-phase stationary coordinate system;

[0100] According to the grid voltage phase angle, performing two-phase rotation to two-phase stationary coordinate transformation processing on the direct current components of odd harmonic voltage reference value of three-phase converter, to obtain the three-phase converter odd harmonic voltage vector reference value in two-phase stationary coordinate system;

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

[0102] It should be noted that, according to the first grid voltage phase angle the direct current component of positive sequence voltage reference value of three-phase converter performing two-phase rotation to two-phase stationary coordinate transformation processing can obtain the three-phase converter positive sequence voltage vector reference value in two-phase stationary coordinate system .

[0103] According to the first grid voltage phase angle respectively on the direct current component of first fifth harmonic voltage reference value of three-phase converter direct current component of first seventh harmonic voltage reference value of three-phase converter The two-phase rotating-to-two-phase stationary coordinate transformation processing is performed on the second five-order harmonic voltage reference value of the three-phase converter and the first seven-order harmonic voltage reference value of the three-phase converter .

[0104] According to the second grid voltage phase angle and the rotor phase angle , the two-phase rotating-to-two-phase stationary coordinate transformation processing is performed on the second five-order harmonic voltage reference value of the three-phase converter and the second seven-order harmonic voltage reference value of the three-phase converter , so as to obtain the corresponding three-phase converter odd harmonic voltage vector reference value; specifically including the second five-order harmonic voltage vector reference value of the three-phase converter and the second seven-order harmonic voltage vector reference value of the three-phase converter .

[0105] The three-phase converter positive sequence voltage vector reference value , the first five-order harmonic voltage vector reference value of the three-phase converter , the first seven-order harmonic voltage vector reference value of the three-phase converter , the second five-order harmonic voltage vector reference value of the three-phase converter , and the second seven-order harmonic voltage vector reference value of the three-phase converter are summed to obtain the three-phase converter voltage vector reference value in the two-phase stationary coordinate system .

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

[0107] The overall calculation and analysis process of the variable frequency transformer fault ride-through control of the embodiment can be referred to Figure 3 , and the calculated three-phase converter voltage vector reference value is subjected to space vector modulation SVPWM to obtain the control signal of the three-phase converter switch , , ; based on the control signal, the variable frequency transformer fault ride-through control can be realized.

[0108] The application provides a variable-frequency transformer fault ride-through control method for adjusting harmonic distortion, which is applied to a variable-frequency transformer fault ride-through circuit.

[0109] For ease of understanding, please refer to Figure 4 The application provides an embodiment of a variable-frequency transformer fault ride-through control device for adjusting harmonic distortion, which is applied to a variable-frequency transformer fault ride-through circuit.

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

[0111] A rotor winding of the variable-frequency transformer is connected with the second power grid;

[0112] An AC input end of the three-phase transformer is connected with an AC end of the three-phase converter;

[0113] A DC end of the three-phase converter is connected with a DC input end of the H-bridge converter and a DC capacitor;

[0114] A DC output end of the H-bridge converter is connected with a DC motor of the variable-frequency transformer;

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

[0116] The control device comprises:

[0117] A parameter acquisition unit 201 is configured to acquire power grid voltages, stator winding parameters, three-phase converter parameters, capacitor voltages and rotor phase angles, wherein the power grid voltages include voltages of the first power grid and the second power grid, and the stator winding parameters and the three-phase converter parameters each include voltages and currents;

[0118] The first analysis unit 202 is configured to analyze and process the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle to obtain the stator winding reactive power, the three-phase converter positive sequence current direct current component and a plurality of stator winding odd harmonic direct current components.

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

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

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

[0122] Further, the first analysis unit 202 comprises:

[0123] The power calculation sub-unit 2021 is configured to perform power calculation according to the stator winding parameter to obtain the stator winding reactive power.

[0124] The component calculation sub-unit 2022 is configured to perform phase-locked loop processing, three-phase stationary to two-phase rotating coordinate transformation and wave filter filtering processing on the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle respectively to obtain the three-phase converter positive sequence current direct current component and the plurality of stator winding odd harmonic direct current components.

[0125] Further, the component calculation sub-unit 2022 is specifically configured to:

[0126] The grid voltage and the three-phase converter parameter are subjected to phase-locked loop processing respectively to obtain the grid voltage phase angle and the three-phase converter phase angle.

[0127] The current parameter of the three-phase converter parameter is subjected to three-phase stationary to two-phase rotating coordinate transformation processing according to the three-phase converter voltage phase angle to obtain the three-phase converter positive sequence current direct current component.

[0128] The stator winding parameter is subjected to three-phase stationary to two-phase rotating coordinate transformation and first preset frequency wave filter filtering processing according to the grid voltage phase angle to obtain the stator winding fifth harmonic voltage direct current component and the stator winding seventh harmonic voltage direct current component.

[0129] According to the grid voltage phase angle and the rotor phase angle, the stator winding parameters are sequentially subjected to three-phase static to two-phase rotating coordinate transformation and second preset frequency trap filter processing, so that the stator winding fifth harmonic current DC component and the stator winding seventh harmonic current DC component are obtained.

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

[0131] According to the grid voltage phase angle, the three-phase converter positive sequence voltage reference value DC component is subjected to two-phase rotating to two-phase static coordinate transformation processing, so that the three-phase converter positive sequence voltage vector reference value in the two-phase static coordinate system is obtained.

[0132] According to the grid voltage phase angle, the three-phase converter odd harmonic voltage reference value DC component is subjected to two-phase rotating to two-phase static coordinate transformation processing, so that the three-phase converter odd harmonic voltage vector reference value in the two-phase static coordinate system is obtained.

[0133] The three-phase converter positive sequence voltage vector reference value and the three-phase converter odd harmonic voltage vector reference value are summed, so that the three-phase converter voltage vector reference value in the two-phase static coordinate system is obtained.

[0134] The application further 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 configured to store program code and transmit the program code to the processor.

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

[0137] The application further provides a computer readable storage medium, the computer readable storage medium is configured to store program code, the program code is configured to execute the harmonic distortion adjusting variable frequency transformer fault ride-through control method in the above method embodiments.

[0138] In several embodiments provided in the 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, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units or components shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0139] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e. may be located in one place, or may be distributed on multiple network units. Part or all of the units may be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0140] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

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

[0142] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of variable frequency transformer fault ride-through control that regulates harmonic distortion, characterized by, The control method is applied to a variable frequency transformer fault ride-through circuit, and the circuit comprises 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 direct current capacitor and a control circuit; One end of an alternating current output end of the three-phase transformer is connected with the first power grid, and the other end is connected with a stator winding of the variable frequency transformer; A rotor winding of the variable frequency transformer is connected with the second power grid; An alternating current input end of the three-phase transformer is connected with an alternating current end of the three-phase converter; A direct current end of the three-phase converter is connected with a direct current input end of the H-bridge converter and the direct current capacitor; A direct current output end of the H-bridge converter is connected with a direct current motor of the variable frequency transformer; The control circuit is connected with control signal input ends of the three-phase converter and the H-bridge converter respectively; The control method comprises: collecting power grid voltages, stator winding parameters, three-phase converter parameters, capacitor voltages and rotor phase angles, wherein the power grid voltages comprise voltages of the first power grid and the second power grid, and the stator winding parameters and the three-phase converter parameters each comprise voltages and currents; analyzing and processing the power grid voltages, the stator winding parameters, the three-phase converter parameters and the rotor phase angles to obtain stator winding reactive power, three-phase converter positive sequence current direct current components and multiple stator winding odd harmonic direct current components; analyzing and processing the capacitor voltages, the stator winding reactive power, the three-phase converter positive sequence current direct current components and the stator winding odd harmonic direct current components based on a preset voltage control equation to obtain three-phase converter positive sequence voltage reference value direct current components and multiple three-phase converter odd harmonic voltage reference value direct current components; analyzing the three-phase converter positive sequence voltage reference value direct current components and the three-phase converter odd harmonic voltage reference value direct current components according to power grid voltage phase angles and the rotor phase angles to obtain three-phase converter voltage vector reference values in a two-phase stationary coordinate system, wherein the analyzing the three-phase converter positive sequence voltage reference value direct current components and the three-phase converter odd harmonic voltage reference value direct current components according to power grid voltage phase angles and the rotor phase angles to obtain three-phase converter voltage vector reference values in a two-phase stationary coordinate system comprises: performing two-phase rotation to two-phase stationary coordinate transformation processing on the three-phase converter positive sequence voltage reference value direct current components according to power grid voltage phase angles to obtain three-phase converter positive sequence voltage vector reference values in a two-phase stationary coordinate system; performing two-phase rotation to two-phase stationary coordinate transformation processing on the three-phase converter odd harmonic voltage reference value direct current components according to the power grid voltage phase angles to obtain three-phase converter odd harmonic voltage vector reference values in a two-phase stationary coordinate system; summing the three-phase converter positive sequence voltage vector reference values and the three-phase converter odd harmonic voltage vector reference values to obtain three-phase converter voltage vector reference values in a two-phase stationary coordinate system; performing space vector modulation on the three-phase converter voltage vector reference values to generate control signals of three-phase converter switches, and realizing variable frequency transformer fault ride-through control based on the control signals.

2. The method of regulating the fault ride-through control of a variable frequency transformer with harmonic distortion of claim 1, wherein, The analyzing and processing of the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle obtains stator winding reactive power, three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components, and the method comprises: According to the stator winding parameter, power calculation is performed to obtain stator winding reactive power; According to the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle, phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering processing are performed respectively to obtain three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components.

3. The method of regulating the fault ride-through control of a variable frequency transformer with harmonic distortion of claim 2, wherein, The phase-locked loop processing, three-phase static to two-phase rotating coordinate transformation and notch filter filtering processing are performed respectively according to the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle to obtain three-phase converter positive sequence current DC component and multiple stator winding odd harmonic DC components, and the method comprises: The grid voltage and the three-phase converter parameter are subjected to phase-locked loop processing respectively to obtain grid voltage phase angle and three-phase converter phase angle; According to the three-phase converter voltage phase angle, three-phase static to two-phase rotating coordinate transformation processing is performed on the current parameter of the three-phase converter parameter to obtain three-phase converter positive sequence current DC component; According to the grid voltage phase angle, three-phase static to two-phase rotating coordinate transformation and first preset frequency notch filter filtering processing are sequentially performed on the stator winding parameter to obtain stator winding fifth harmonic voltage DC component and stator winding seventh harmonic voltage DC component; According to the grid voltage phase angle and the rotor phase angle, three-phase static to two-phase rotating coordinate transformation and second preset frequency notch filter filtering processing are sequentially performed on the stator winding parameter to obtain stator winding fifth harmonic current DC component and stator winding seventh harmonic current DC component.

4. A variable frequency transformer fault ride through control device that regulates harmonic distortion, characterized by, The control device is applied in a variable frequency transformer fault ride-through circuit, and the circuit comprises a first grid, a second grid, a three-phase transformer, a three-phase converter, a variable frequency transformer, an H-bridge converter, a direct current capacitor and a control circuit; One end of an alternating current output end of the three-phase transformer is connected with the first grid, and the other end is connected with a stator winding of the variable frequency transformer; A rotor winding of the variable frequency transformer is connected with the second grid; An alternating current input end of the three-phase transformer is connected with an alternating current end of the three-phase converter; A direct current end of the three-phase converter is connected with a direct current input end of the H-bridge converter and the direct current capacitor; A direct current output end of the H-bridge converter is connected with a direct current motor of the variable frequency transformer; The control circuit is connected with control signal input ends of the three-phase converter and the H-bridge converter respectively; The control device comprises: A parameter acquisition unit is configured to acquire grid voltage, stator winding parameter, three-phase converter parameter, capacitor voltage and rotor phase angle, the grid voltage comprises voltage of the first grid and the second grid, and the stator winding parameter and the three-phase converter parameter each comprise voltage and current; The first analysis unit is configured to analyze the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle to obtain stator winding reactive power, three-phase converter positive sequence current DC component and a plurality of stator winding odd harmonic DC components. The second analysis unit is configured to analyze 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 three-phase converter positive sequence voltage reference DC component and a plurality of three-phase converter odd harmonic voltage reference DC components. The third analysis unit is configured to analyze the three-phase converter positive sequence voltage reference DC component and the three-phase converter odd harmonic voltage reference DC component according to the grid voltage phase angle and the rotor phase angle to obtain three-phase converter voltage vector reference in a two-phase stationary coordinate system. The third analysis unit is configured to perform two-phase rotation to two-phase stationary coordinate transformation on the three-phase converter positive sequence voltage reference DC component according to the grid voltage phase angle to obtain three-phase converter positive sequence voltage vector reference in a two-phase stationary coordinate system. The third analysis unit is configured to perform two-phase rotation to two-phase stationary coordinate transformation on the three-phase converter odd harmonic voltage reference DC component according to the grid voltage phase angle to obtain three-phase converter odd harmonic voltage vector reference in a two-phase stationary coordinate system. The third analysis unit is configured to sum the three-phase converter positive sequence voltage vector reference and the three-phase converter odd harmonic voltage vector reference to obtain three-phase converter voltage vector reference in a two-phase stationary coordinate system. The modulation control unit is configured to perform space vector modulation on the three-phase converter voltage vector reference to generate a control signal of the three-phase converter switch, and to realize variable frequency transformer fault ride-through control based on the control signal.

5. The harmonic distortion regulated VAR tap changer fault ride through control device of claim 4, wherein, The first analysis unit comprises: The power calculation sub-unit is configured to perform power calculation according to the stator winding parameter to obtain stator winding reactive power. The component calculation sub-unit is configured to perform phase-locked loop processing, three-phase stationary to two-phase rotating coordinate transformation and wave filter filtering processing on the grid voltage, the stator winding parameter, the three-phase converter parameter and the rotor phase angle respectively to obtain three-phase converter positive sequence current DC component and a plurality of stator winding odd harmonic DC components.

6. The harmonic distortion regulated VAR tap changer fault ride through control device of claim 5, wherein, The component calculation sub-unit is specifically configured to: Perform phase-locked loop processing on the grid voltage and the three-phase converter parameter respectively to obtain grid voltage phase angle and three-phase converter phase angle. Perform three-phase stationary to two-phase rotating coordinate transformation on current parameter of the three-phase converter parameter according to the three-phase converter voltage phase angle to obtain three-phase converter positive sequence current DC component. Perform three-phase stationary to two-phase rotating coordinate transformation and first preset frequency wave filter filtering processing on the stator winding parameter according to the grid voltage phase angle in sequence to obtain stator winding fifth harmonic voltage DC component and stator winding seventh harmonic voltage DC component. The stator winding parameters are sequentially subjected to three-phase static to two-phase rotating coordinate transformation and second preset frequency trap filter processing according to the grid voltage phase angle and the rotor phase angle, so as to obtain a stator winding fifth harmonic current direct current component and a stator winding seventh harmonic current direct current component.

7. A variable frequency transformer fault ride through control device that regulates harmonic distortion, characterized by, The device comprises a processor and a memory; The memory is configured to store program code and transmit the program code to the processor; The processor is configured to execute the method for controlling fault ride-through of a variable-frequency transformer with harmonic distortion adjustment according to instructions in the program code.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium is configured to store program code, and the program code is configured to execute the method for controlling fault ride-through of a variable-frequency transformer with harmonic distortion adjustment.

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