CN108270223B - Method and system for controlling network side reactive power of wind power converter - Google Patents
Method and system for controlling network side reactive power of wind power converter Download PDFInfo
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Abstract
The invention relates to a method and a system for controlling network-side reactive power of a wind power converter. This wind power converter net side reactive power control system includes: the reactive power calculation module is used for calculating the reactive power of a line between the grid-side inverter and the compensation capacitor based on the current and the voltage of the line between the grid-side inverter and the compensation capacitor; the reactive power compensation module is used for compensating the reactive power based on the capacitance value of the compensation capacitor to obtain compensated reactive power; and the control signal generation module is used for generating a control signal for controlling the network side reactive power by controlling the network side inverter based on the compensated reactive power, the reactive power given value, the current, the direct current bus voltage at the direct current side of the converter main loop and the direct current bus voltage given value.
Description
Technical Field
The present invention relates generally to the field of wind power. And more particularly, to a grid-side reactive power control method and system for a wind power converter.
Background
With the rapid growth of economy and the overall progress of society, the problems of energy supply and environmental pollution in China are more and more prominent. The need to develop and utilize renewable energy sources is more pressing. Wind energy is the most important component of renewable energy and the only economic power generation mode, and has good social effect and economic benefit due to cleanness, no pollution, short construction period, flexible investment and small occupied area, so that the wind energy is highly valued by governments of all countries in the world. With the rapid development of wind power generation technology and the national policy attention on renewable energy power generation, the construction of wind power generation in China has entered a rapid development period. Wind resources in China are abundant, but areas suitable for large-scale wind power development are generally located at the tail end of a power grid, and due to the fact that the grid structure of the power grid is weak, a series of problems that the voltage level of the power grid is reduced, the transmission power of a line exceeds a thermal limit, the short-circuit capacity of a system is increased, the transient stability of the system is changed and the like can occur after large-scale wind power is connected into the power grid. With the increase of the scale of the wind power plant, the interaction between the wind power plant and the power grid is larger and the requirements of the system on the wind power generation system are stricter. Two main requirements for wind power systems are reactive power control in normal operating conditions and ride-through capability in fault conditions.
For reactive power control, generally, voltage regulation is performed on energy conversion devices such as a permanent magnet direct-drive wind turbine generator, a wind power full-power converter and the like by a reactive power open-loop control method. However, with the development of the grid-connected scale of the wind turbine, the requirements on the accuracy and the response speed of the voltage regulation control are higher and higher, but the traditional reactive power open-loop control method cannot meet the requirement on the control accuracy.
Therefore, a method and a system for controlling the grid-side reactive power of the wind power converter, which meet the requirement of higher control accuracy, are needed.
Disclosure of Invention
In order to at least solve the problem that the traditional reactive power control method cannot meet the requirement of control precision, the wind power converter grid-side reactive power control method and system are provided.
According to an aspect of the present invention, the present invention provides a grid-side reactive power control system of a wind power converter, comprising: the reactive power calculation module is used for calculating the reactive power of a line between the grid-side inverter and the compensation capacitor based on the current and the voltage of the line between the grid-side inverter and the compensation capacitor; the reactive power compensation module is used for compensating the reactive power based on the capacitance value of the compensation capacitor to obtain compensated reactive power; and the control signal generation module is used for generating a control signal for controlling the network side reactive power by controlling the network side inverter based on the compensated reactive power, the reactive power given value, the current, the direct current bus voltage at the direct current side of the converter main loop and the direct current bus voltage given value.
According to another aspect of the invention, the invention provides a grid-side reactive power control method for a wind power converter, which comprises the following steps: calculating reactive power of a line between a grid-side inverter and a compensation capacitor based on current and voltage of the line between the grid-side inverter and the compensation capacitor; compensating the reactive power based on the capacitance value of the compensation capacitor to obtain compensated reactive power; and generating a control signal for controlling the grid side reactive power by controlling the grid side inverter based on the compensated reactive power, the reactive power given value, the current, the direct current bus voltage at the direct current side of the converter main loop, and the direct current bus voltage given value.
According to the wind power converter network side reactive power control method and system, closed-loop control over the wind power converter network side reactive power is achieved by calculating the fan grid-connected point reactive power, and control accuracy of controlling the wind power converter network side reactive power is improved.
Drawings
The invention may be better understood from the following description of specific embodiments thereof taken in conjunction with the accompanying drawings, in which:
fig. 1 shows a block diagram of a grid-side reactive power control system of a wind power converter according to an embodiment of the invention;
fig. 2 shows a flowchart of a method for controlling grid-side reactive power of a wind power converter according to an embodiment of the present invention.
Description of reference numerals:
101: a permanent magnet synchronous generator; 102: a rectifier; 103: the direct current side of a main loop of the converter; 104: a grid-side inverter; 105: a grid side output point A; 106: a compensation capacitor; 107: fan grid connection points; 108: a step-up transformer; 109: a power grid; 110: a current sensor; 111: a voltage sensor; 1000: wind power converter net side reactive power control system: 1010: a reactive power calculation module: 1011: a first coordinate transformation module; 1012: a second coordinate transformation module; 1013: a calculation module; 1020: a reactive power compensation module; 1030: a control signal generation module; 1031: a reactive power controller; 1032: a Q-axis current controller; 1033: a DC bus voltage controller; 1034: a D-axis current controller; 1035: a modulation module; 1036: a q-axis reference voltage calculation module; 1037: and a d-axis reference voltage calculation module.
Detailed Description
Features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is in no way limited to any specific configuration and algorithm set forth below, but rather covers any modification, replacement or improvement of elements, components or algorithms without departing from the spirit of the invention. In the drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessarily obscuring the present invention.
Fig. 1 is a block diagram illustrating a grid-side reactive power control system 1000 of a wind power converter according to an embodiment of the present invention. As shown in fig. 1, the grid-side reactive power control system 1000 of the wind power converter includes a reactive power calculation module 1010, a reactive power compensation module 1020, and a control signal generation module 1030. Details regarding each of the modules of the wind power converter grid-side reactive power control system 1000 are further described below.
As shown in fig. 1, the wind power system includes a power generation device, a wind power converter, and a power grid. The power generation device is used to generate electrical energy from the available wind energy. In one embodiment, the power generation device is a permanent magnet synchronous generator 101. Permanent magnet synchronous generator 101 is used to convert wind energy received from a wind turbine in mechanical form into three-phase alternating current. It will be appreciated that the three-phase ac current referred to herein is intended to be exemplary of one form of electrical energy. In other embodiments, the electrical energy may also comprise multi-phase alternating current or direct current.
As shown in fig. 1, the wind power converter comprises a dc side 103 comprising a rectifier 102, a grid-side inverter 104 and a converter main loop electrically connected between the rectifier 102 and the grid-side inverter 104. The rectifier 102 is used to convert three-phase ac power to dc power. The dc power is delivered to the dc side 103 of the converter main loop. The dc side 103 of the converter main loop may comprise one or more capacitors connected in series or in parallel. The dc side 103 of the converter main circuit is used to mitigate voltage fluctuations on the dc side 103 of the converter main circuit during ac rectification. The dc power is thereafter transmitted to the grid-side inverter 104. The grid-side inverter 104 is configured to convert the direct current into a three-phase alternating current under the action of the grid-side reactive power control system 1000 of the wind power converter. The three-phase ac power is then combined into the grid 109 for transmission.
In one embodiment, the rectifier 102 and the grid-side inverter 104 have a three-phase two-level topology that includes a number of semiconductor switches controlled using Pulse Width Modulation (PWM) or Space Vector Pulse Width Modulation (SVPWM). In other embodiments, the rectifier 102 and the grid-side inverter 104 may also have a three-phase, three-level topology. The semiconductor switches may employ any suitable switching elements, such as Insulated Gate Bipolar Transistors (IGBTs), Gate Commutated Thyristors (GCTs), metal-oxide-semiconductor-field effect transistors (MOSFETs).
In the embodiment shown in fig. 1, when the reactive capacity of the wind turbine generator set alone cannot meet the system voltage regulation requirement, the wind turbine generator system further comprises a reactive power compensation device. The wind power plant reactive compensation device can adopt a capacitor or a reactor group which is switched in groups, and can adopt a static reactive compensator which can be continuously adjusted or other more advanced reactive compensation devices when necessary. When the power generation device is a wind turbine of a direct-drive synchronous motor, such as the permanent magnet synchronous motor 101, because the permanent magnet synchronous generator 101 does not need to absorb reactive power from a power grid to establish a magnetic field, a wind farm using the permanent magnet synchronous generator only needs a small amount of reactive compensation devices, and a large amount of harmonic waves are not generated in the working process. The reactive compensation means can thus use the compensation capacitance 106.
In the embodiment shown in fig. 1, the grid-side reactive power control system 1000 of the wind power converter further includes a current sensor 110 and a voltage sensor 111. The current sensor 110 and the voltage sensor 111 are both electrically connected between the grid-side inverter 104 and the compensation capacitor 106. The current sensor 110 is adapted to sense the current I delivered to the compensation capacitor 106 and to provide a feedback current I in response theretofbTo the reactive power calculation module 1010. In one embodiment, the current I comprises a three-phase current I flowing on the transmission linea、Ib、Ic. The voltage sensor 111 is used to detect the voltage U delivered to the compensation capacitor 106 and provide a feedback voltage U in response to the voltage UfbTo the reactive power calculation module 1010. In one embodiment, the voltage isU may comprise a three-phase line voltage U on a transmission linea、Ub、Uc. In one embodiment, the wind power converter grid-side reactive power control system 1000 may further include a dc voltage sensor and a capacitance detector. The dc voltage sensor is electrically connected to the dc side 103 of the main loop of the converter for sensing the dc voltage applied to the dc side 103 of the main loop of the converter and providing a feedback dc voltage U in response theretoDC_fbTo the control signal generation module 1030. The capacitance detector is electrically connected to the compensation capacitor 106 for detecting a capacitance C of the compensation capacitor 106 and feeding back the capacitance C to the reactive power compensation module 1020. In one embodiment, the reactive power compensation module 1020 may be an LC filter reactive compensation module 1020. Wind power converter grid-side reactive power control system 1000 based on feedback current IfbFeedback voltage UfbFeedback DC voltage UDC_fbAnd a feedback capacitance value C and provides control signals to the grid-side inverter 104 in response to various system commands. The various system instructions referred to herein may include capacitive reactive power compensation, PI (proportional integral) control algorithms. More details regarding the wind power converter grid-side reactive power control system 1000 will be described further below.
In one embodiment, the circuit sensor 110 and the voltage sensor 111 may be disposed outside the grid-side reactive power control system 1000 of the wind power converter.
In the embodiment shown in fig. 1, the reactive power calculation module 1010 includes a first coordinate transformation module 1011, a second coordinate transformation module 1012, and a calculation module 1013.
As shown in fig. 1, the first coordinate transformation module 1011 is electrically connected to the voltage sensor 111 for receiving the feedback voltage U from the voltage sensor 111fb. The first coordinate transformation module 1011 is used for transforming the feedback voltage UfbThe feedback voltage component is converted out. In one embodiment, the first coordinate transformation module 1011 may include a phase-locked loop circuit. In a synchronously rotating two-phase d-q reference frame, the voltage component converted from the phase-locked loop circuit includes a d-axis voltage Ud(active voltage component) and q-axis electricityPress Ud(reactive voltage component). In one embodiment, the phase-locked loop circuit is further configured to receive the feedback voltage U from the feedback circuitfbThe phase angle theta is extracted. Specific embodiments of phase-locked loop circuits are well known in the art and will not be described herein. The second coordinate transformation module 1012 is electrically connected to the current sensor 110 for receiving the feedback current I output from the current sensor 110fb. The second coordinate transformation module 1012 is used for transforming the feedback current I according to the phase angle theta extracted by the first coordinate transformation module 1011fbThe current component is converted out. The converted current component from the second coordinate transformation module 1012 includes the d-axis current I in the d-q reference framed(active current component) and q-axis current Iq(reactive current component).
In the embodiment shown in fig. 1, the calculating module 1013 is electrically connected to the first coordinate transformation module 1011 and the second coordinate transformation module 1012 for receiving the converted voltage component and current component and calculating the reactive power Q at a point a between the grid-side inverter 104 and the compensation capacitor 106 based on the voltage component and the current componentA. The reactive power compensation module 1020 is connected to the calculation module 1013 to receive the calculated reactive power QAAnd based on said reactive power QACalculating the reactive power compensation value Q by the capacitance value C and the voltage component of the compensation capacitor 106CAnd based on reactive power QAAnd a reactive power compensation value QCCalculating reactive power Q of fan grid-connected point 107 between compensation capacitor 106 and power grid 109B. Obtaining the reactive power Q of the fan grid-connected pointBThen, the wind power converter grid-side reactive power control system 1000 can execute reactive power control according to a given reactive power instruction. Details about the calculation of the above-mentioned wind turbine grid-connected point reactive power will be described in detail below.
In the embodiment shown in fig. 1, the control signal generation module 1030 comprises a modulation module 1035, a Q-axis reference voltage calculation module 1036, and a d-axis reference voltage calculation module 1037, wherein the Q-axis reference voltage calculation module 1036 comprises a reactive power controller 1031 and a Q-axis current controller 1032; the D-axis reference voltage calculation module 1037 includes a dc bus voltage controller 1033 and a D-axis currentA controller 1034. The Q-axis reference voltage calculation module 1036 first calculates the reactive power Q of the fan grid-connected pointBAnd the given value Qq _ set of the reactive power are subtracted, and the difference value is processed by a reactive power controller 1031 in the q-axis reference voltage calculation module to obtain a q-axis current reference value (reactive current reference value) Iq_ref(ii) a The Q-axis current reference value (reactive current reference value) I is then referenced to by the Q-axis current controller 1032 in the Q-axis reference voltage calculation module 1036q_refAnd q-axis current IqProcessing the reference voltage to generate a q-axis reference voltage Uq_ref. The d-axis reference voltage calculation module 1037 first detects a dc bus feedback voltage U obtained by the dc side 103 of the main circuit of the converter for the dc voltage sensorDC_fbAnd a DC voltage reference value UDC_refProcessing is performed and then a d-axis current reference value (reactive current reference value) I is generated by a dc bus voltage controller 1033 in the d-axis reference voltage calculation module 1037d_refAnd for d-axis current reference value (reactive current reference value) Id_refAnd d-axis current Id(active component of current) to obtain active voltage reference value Ud_ref. The modulation module 1035 is electrically connected to the Q-axis current controller 1033 and the D-axis current controller 1034 for receiving the Q-axis reference voltage Uq_refAnd an active voltage reference value Ud_refAnd for the q-axis reference voltage Uq_refAnd an active voltage reference value Ud_refAnd processing to obtain an IGBT gate drive signal. The IGBT gate drive signals are input to the grid-side inverter 104 to drive the grid-side inverter 104 to produce the desired output current.
The following describes in detail the reactive power Q of the fan grid-connection point connecting the compensation capacitor 106 to the grid 109BAnd (4) calculating mode. The first coordinate transformation module 1011 receives a feedback voltage from the voltage sensor 111. The first coordinate transformation module 1011 transforms the feedback voltage from three phases to two phases, and more specifically, the first coordinate transformation module 1011 transforms the fed-back three-phase voltage signal Ua、Ub、UcObtaining a voltage U under a αβ axis system through constant power conversion from a static three-phase abc coordinate system to a static two-phase αβ coordinate axis systemα、Uβ(ii) a Wherein the stationary three-phase abc coordinate system is represented byThe stationary two-phase αβ coordinate axis constant power transformation formula is as follows:
and the voltage U at the axis line of αβ is converted based on the following formula (2) according to the voltage phase angle theta extracted by the phase-locked loop circuitα、UβConversion into a two-phase voltage component U in a d-q coordinate systemdAnd Uq：
The second coordinate transformation module 1012 receives the feedback current from the current sensor 110. The second coordinate transformation module 1012 rotates the feedback current from three phases to two phases, and more particularly, the second coordinate transformation module 1012 converts the fed back three-phase current signal Ia、Ib、IcObtaining a voltage I under a αβ axis system through constant power conversion from a static three-phase abc coordinate system to a static two-phase αβ coordinate axis systemα、IβThe constant power conversion formula from a static three-phase abc coordinate system to a static two-phase αβ coordinate system is as follows:
and the voltage I at the axis line of αβ is converted based on the following formula (4) according to the voltage phase angle theta extracted by the phase-locked loop circuitα、IβConverted into two-phase current component I under d-q coordinate systemdAnd Iq：
The calculation module 1013 receives the two-phase voltage component U from the first coordinate transformation module 1011 and the second coordinate transformation module 1012dAnd UqAnd two-phase current component IdAnd IqCalculating a voltage vector UsPhase angle theta of sum voltage vectoruSum current vector IsPhase angle theta of sum current vectorIThe calculation formula is as follows:
then based on the voltage vector UsPhase angle theta of sum voltage vectoruSum current vector IsPhase angle theta of sum current vectorICalculating the reactive power Q between the grid-side inverter 104 and the compensation capacitor 106AThe specific calculation formula is as follows:
the reactive power compensation module 1020 receives the calculated reactive power Q from the calculation module 1013 and the second coordinate transformation module 1012 respectivelyAVoltage vector and capacitance value C, and calculating a reactive power compensation value Q based on the following formula (10)C：
Where ω is the grid-side voltage angular frequency between the grid-side inverter 104 and the compensation capacitor 106, C is the capacitance of the capacitor in the compensation capacitor 106, and the calculated reactive power compensation value Q is obtainedCIs the amount of reactive power absorbed by the capacitors in the compensation capacitance 106.
The second reactive power calculation circuit 1405 comprises a summing element coupled to the slave calculation module 1013 and to the LC filterThe reactive compensation module 1020 receives the calculated reactive power QAAnd a reactive power compensation value QCSumming to obtain the reactive power Q of the fan grid-connected point 107 connecting the compensation capacitor 106 and the power grid 109BThe concrete formula is as follows:
reactive power regulator 1406 receives the calculated fan grid-connected point reactive power Q from second reactive power calculation circuit 1405BAnd uses the subtraction element included in the power supply to carry out reactive power Q on the wind turbine grid-connected pointBCalculating a difference value with a given reactive power value Qq _ set, and processing the difference value to obtain a q-axis current reference value (reactive current reference value) Iq_ref。
In another embodiment, the current sensor 110 and the voltage sensor 111 may directly detect the current and voltage of the fan grid-connected point 107 between the compensation capacitor 106 and the grid 109. Because the current and the voltage of the fan grid-connected point 107 are directly collected, the reactive power Q absorbed by a capacitor in the compensation capacitor 106 does not need to be calculatedCThe fan grid-connected point reactive power may be calculated directly based on the detected current and voltage. The control signal generating module 1030 generates a control signal for controlling the grid-side inverter and further controlling the grid-side reactive power based on the grid-connected point reactive power, the reactive power set value, the current, the direct-current bus voltage on the direct-current side of the main circuit of the converter, and the direct-current bus voltage set value.
Fig. 2 shows a flowchart of a method for controlling grid-side reactive power of a wind power converter according to an embodiment of the present invention.
In step 210, the reactive power of the line between the grid-side inverter and the compensation capacitor is calculated based on the current and voltage of the line between the grid-side inverter and the compensation capacitor. In one embodiment, the current I and the voltage U between the grid-side inverter and the compensation capacitor are measured by a current sensor and a voltage sensor, the current I comprising a three-phase current Ia、Ib、IcThe voltage U comprises a three-phase line voltage Ua、Ub、Uc(ii) a Coordinate conversion is carried out on three-phase current and three-phase voltage through a coordinate conversion module to obtain d-axis current and Q-axis current of the current and d-axis voltage and Q-axis voltage of the voltage, phase locking processing is carried out on the voltage through a phase locking loop to obtain a phase angle theta, and then reactive power Q of a line A point between a grid-side inverter and a compensation capacitor is calculated based on the d-axis current, the Q-axis current, the d-axis voltage, the Q-axis voltage and the phase angle thetaA。
In step 220, the reactive power obtained by calculation is compensated based on the capacitance value of the compensation capacitor, so as to obtain compensated reactive power. In one embodiment, a capacitance value C of the compensation capacitor is obtained by a capacitance detector, and the reactive power Q absorbed by the compensation capacitor is calculated based on the capacitance value CCBased on the absorbed reactive power QCCompensating the reactive power of the point A to obtain the reactive power Q of the fan grid-connected pointB。
In step 230, a control signal for controlling the grid-side inverter and thus controlling the grid-side reactive power is generated based on the compensated reactive power, the reactive power set value, the current, the dc bus voltage on the dc side of the main circuit of the converter, and the dc bus voltage set value. In one embodiment, the reactive power Q is obtained by connecting the wind turbine with the gridBCalculating the difference with the given value of reactive power, and processing the difference to generate q-axis reference current Iq_refThen based on the q-axis reference current Iq_refAnd q-axis current to calculate q-axis reference voltage Uq_ref(ii) a By applying a DC bus voltage UDC_fbGiven value U of sum DC bus voltageDC_setProcessed to generate d-axis reference current Id_refThen based on the d-axis reference current Id_refAnd d-axis current to calculate d-axis reference voltage Ud_ref(ii) a (ii) a Then passes through the modulation module pair
Reference voltage U based on q axisq_refAnd d-axis reference voltage Ud_refAnd processing the data to generate a control signal for controlling the grid-side inverter so as to control the grid-side reactive power.
In another embodiment, the current and voltage of the fan grid-connected point 107 between the compensation capacitor 106 and the grid 109 may be directly detected by the current sensor 110 and the voltage sensor 111. Because the current and the voltage of the fan grid-connected point 107 are directly collected, the reactive power absorbed by a capacitor in the compensation capacitor 106 does not need to be calculated, and the reactive power of the fan grid-connected point is directly calculated based on the detected current and voltage; and then generating a control signal for controlling the grid-side inverter and further controlling the grid-side reactive power based on the grid-connected point reactive power, the reactive power set value, the current, the direct-current bus voltage at the direct-current side of the main circuit of the converter and the direct-current bus voltage set value.
Embodiments and implementations of the apparatus and methods described herein may include various operations that may be implemented in machine-executable instructions executed by a computer apparatus. The computer apparatus may include one or more general purpose or special purpose computers (or other electronic devices). The computer apparatus may include hardware components that include specific logic for performing operations or may include a combination of hardware, software, and/or firmware.
It should be appreciated that many of the elements described in this specification may be implemented as one or more components, which are terms used to particularly emphasize their implementation independence. For example, a component may be implemented as a hardware circuit comprising custom Very Large Scale Integration (VLSI) circuits or gate arrays, or off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A component may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the description and claims of the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprise" or "comprises", and the like, means that the element or item listed before "comprises" or "comprising" covers the element or item listed after "comprising" or "comprises" and its equivalents, and does not exclude other elements or items. "connected," and like terms, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.
Although the foregoing has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be made without departing from the principles thereof. It should be noted that there are many alternative ways of implementing the processes and apparatuses described herein. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims, and all changes that come within the meaning and range of equivalents of the claims are intended to be embraced therein.
Claims (8)
1. The utility model provides a wind power converter net side reactive power control system which characterized in that, this wind power converter net side reactive power control system includes:
the reactive power calculation module is used for calculating the reactive power of a line between a grid-side inverter and a compensation capacitor based on the current and the voltage of the line between the grid-side inverter and the compensation capacitor, and the compensation capacitor is arranged between the grid-side inverter and a fan grid-connected point;
the reactive power compensation module is used for calculating reactive power absorbed by the compensation capacitor based on the capacitance value of the compensation capacitor and compensating the reactive power of a line between the grid-side inverter and the compensation capacitor based on the absorbed reactive power to obtain compensated reactive power, and the compensated reactive power represents the reactive power of the fan grid-connected point; and
and the control signal generation module is used for generating a control signal for controlling the grid-side inverter to control the grid-side reactive power in a closed loop mode based on the compensated reactive power, the reactive power given value, the current, the direct-current bus voltage at the direct-current side of the main circuit of the converter and the direct-current bus voltage given value.
2. The wind power converter grid-side reactive power control system of claim 1, further comprising:
a current sensor that detects a current of a line between the grid-side inverter and the compensation capacitor; and
and a voltage sensor that detects a voltage of a line between the grid-side inverter and the compensation capacitor.
3. The grid-side reactive power control system of a wind power converter according to claim 1 or 2, wherein the reactive power calculation module comprises:
the first coordinate transformation module is used for transforming the current to obtain a corresponding d-axis current and a corresponding q-axis current;
the second coordinate transformation module is used for transforming the voltage to obtain corresponding d-axis voltage and q-axis voltage; and
and the calculation module is used for calculating the reactive power of a line between the grid-side inverter and the compensation capacitor based on the d-axis current, the q-axis current, the d-axis voltage and the q-axis voltage.
4. The grid-side reactive power control system of claim 3, wherein the control signal generation module comprises:
a q-axis reference voltage calculation module that calculates a q-axis reference voltage based on the compensated reactive power, the reactive power given value, and the q-axis current;
the d-axis reference voltage calculation module is used for calculating d-axis reference voltage based on the direct-current bus voltage, the direct-current bus voltage given value and the d-axis current; and
a modulation module that generates the control signal based on the q-axis reference voltage and the d-axis reference voltage.
5. A wind power converter grid-side reactive power control method is characterized by comprising the following steps:
calculating reactive power of a line between a network side inverter and a compensation capacitor based on current and voltage of the line between the network side inverter and the compensation capacitor, wherein the compensation capacitor is arranged between the network side inverter and a fan grid-connected point;
calculating reactive power absorbed by the compensation capacitor based on a capacitance value of the compensation capacitor, and compensating the reactive power of a line between the grid-side inverter and the compensation capacitor based on the absorbed reactive power to obtain compensated reactive power, wherein the compensated reactive power represents the reactive power of the fan grid-connected point; and
and generating a control signal for controlling the network side reactive power in a closed loop manner by controlling the network side inverter based on the compensated reactive power, the reactive power set value, the current, the direct current bus voltage at the direct current side of the main circuit of the converter and the direct current bus voltage set value.
6. The grid-side reactive power control method of the wind power converter according to claim 5, further comprising:
detecting, by a current sensor, a current of a line between the grid-side inverter and the compensation capacitor; and
the voltage of a line between the grid-side inverter and the compensation capacitor is detected by a voltage sensor.
7. The wind power converter grid-side reactive power control method according to claim 5 or 6, wherein calculating the reactive power of the line between the grid-side inverter and the compensation capacitor comprises:
converting the current to obtain corresponding d-axis current and q-axis current;
converting the voltage to obtain corresponding d-axis voltage and q-axis voltage; and
and calculating the reactive power of a line between the grid-side inverter and the compensation capacitor based on the d-axis current, the q-axis current, the d-axis voltage and the q-axis voltage.
8. The wind power converter grid-side reactive power control method of claim 7, wherein generating control signals for controlling grid-side reactive power by controlling the grid-side inverter based on the compensated reactive power, the reactive power setpoint, the current, the dc bus voltage on the dc side of the converter main loop, the dc bus voltage setpoint comprises:
calculating a q-axis reference voltage based on the compensated reactive power, the reactive power given value and the q-axis current;
calculating a d-axis reference voltage based on the direct-current bus voltage, the direct-current bus voltage given value and the d-axis current; and
generating the control signal based on the q-axis reference voltage and the d-axis reference voltage.
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| CN103259290B (en) * | 2012-12-14 | 2015-08-12 | 天津瑞能电气有限公司 | A kind of double-fed generator net side converter direct voltage control method of no phase-locked loop |
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