Converter power factor feedforward compensation control method and device

Abstract

The invention provides a converter power factor feed-forward compensation control method and device, and belongs to the technical field of wind power generation. The method comprises the following steps: acquiring feed-forward compensation control parameters, wherein the feed-forward compensation control parameters comprise a filter parameter, a network side parameter and an input side parameter; calculating an input side target power factor angle according to the feed-forward compensation control parameter; and compensating the actual power factor angle of the input side according to the target power factor angle of the input side. According to the method, an input-side power factor and a network-side power factor are distinguished, a target power factor angle of an input side is calculated according to filter parameters, network-side parameters and input-side parameters under the condition that the network-side power factor reaches 1, and an actual power factor angle of the input side is compensated according to the target power factor angle of the input side. And the influence of the filter on the grid-side power factor angle is compensated.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a converter power factor feedforward compensation control method and a converter power factor feedforward compensation control device. Background Art

[0002] At present, the converter plays a key role in the wind power industry. The converter is responsible for regulating and controlling important electrical quantities such as voltage, current and power. The converter controls active and reactive power by adjusting the input and output voltage and current. However, due to the existence of the grid-side filter of the converter, there will be a certain deviation in the power factor angle before and after the filter, and the power factor is not exactly the same. It is necessary to add a control method to achieve a more accurate control effect.

[0003] The existing converter control method can make the grid-side power factor approximately 1, but does not consider the impact of the grid-side filter. Summary of the invention

[0004] The purpose of an embodiment of the present invention is to provide a converter power factor feedforward compensation control method and device, which distinguishes the input side power factor from the grid side power factor, calculates the target power factor angle of the input side according to the filter parameters, the grid side parameters and the input side parameters when the grid side power factor reaches 1, and compensates the actual power factor angle of the input side according to the target power factor angle of the input side to compensate for the influence of the filter on the grid side power factor angle.

[0005] In order to achieve the above object, the present invention provides a first aspect of a converter power factor feedforward compensation control method, the converter power factor feedforward compensation control method comprising: Obtaining feedforward compensation control parameters, wherein the feedforward compensation control parameters include: filter parameters, grid side parameters, and input side parameters; Calculating the input side target power factor angle according to the feedforward compensation control parameter; The actual power factor angle on the input side is compensated according to the target power factor angle on the input side.

[0006] In some feasible embodiments, the filter parameters include filter capacitance, the grid-side parameters include: grid-side voltage amplitude, grid-side current amplitude and grid-side power factor angle; the input-side parameters include: input voltage angle frequency; The calculating the input side target power factor angle according to the feedforward compensation control parameter comprises: Substituting the feedforward compensation control parameter into the input side power factor angle calculation formula for calculation, the input side target power factor angle is obtained.

[0007] In some feasible embodiments, the input side power factor angle calculation formula is: ; in, is the input side power factor angle, is the filter capacitance, is the input voltage angular frequency, is the grid-side voltage amplitude, is the grid-side current amplitude, is the grid-side power factor angle.

[0008] In some feasible embodiments, the input side power factor angle calculation formula is constructed in the following manner: Construct an equivalent single-phase circuit of the power grid, grid-side filter and converter circuit; Construct voltage and current vector diagrams on the grid side and input side according to the constructed equivalent single-phase circuit; Determine expressions of each voltage and current according to the voltage-current vector diagram; Construct the grid-side state equation; According to the grid-side state equation and the expressions of various voltages and currents, the mathematical model corresponding to the input-side power factor angle is obtained.

[0009] In some feasible embodiments, the expression determined according to the voltage-current vector diagram includes: an equivalent single-phase grid-side voltage expression, an equivalent single-phase grid-side current expression, and an equivalent single-phase input-side current expression; The equivalent single-phase grid-side voltage expression is: ; The equivalent single-phase grid-side current expression is: ; The equivalent single-phase input side current expression is:

[0010] in, is the equivalent single-phase grid-side voltage, is the grid-side voltage amplitude, is the equivalent single-phase grid-side current, is the grid-side current amplitude, is the equivalent single-phase input side current, is the input current amplitude, is the phase angle of the equivalent single-phase grid-side voltage; is the phase angle of the equivalent single-phase grid-side current; is the grid-side power factor angle, is the phase angle of the equivalent single-phase input current.

[0011] In some feasible embodiments, the grid-side state equation includes: ; ; in, is the filter capacitance, is the input voltage angular frequency, is the equivalent single-phase grid-side voltage, is the equivalent single-phase input side voltage, is the equivalent single-phase grid-side current, is the grid-side filter inductance, is the equivalent single-phase input side current, Is an imaginary unit.

[0012] In some feasible embodiments, compensating the input side actual power factor angle according to the input side target power factor angle includes: Determine whether the actual power factor angle on the input side is equal to the target power factor angle on the input side; If the actual power factor angle on the input side is equal to the target power factor angle on the input side, no compensation is required; If the actual power factor angle on the input side is greater than the target power factor angle on the input side, a reduction adjustment strategy is implemented for the actual power factor angle on the input side; If the actual power factor angle on the input side is less than the target power factor angle on the input side, an increasing adjustment strategy is executed on the actual power factor angle on the input side.

[0013] A second aspect of the present application provides a converter power factor feedforward compensation control device, the converter power factor feedforward compensation control device comprising: A parameter acquisition unit, used to acquire feedforward compensation control parameters, wherein the feedforward compensation control parameters include: filter parameters, grid-side parameters and input-side parameters; A calculation unit, used for calculating the input side target power factor angle according to the feedforward compensation control parameter; An execution unit is used to compensate the actual power factor angle on the input side according to the target power factor angle on the input side.

[0014] In some feasible embodiments, the filter parameters include filter capacitance, the grid-side parameters include: grid-side voltage amplitude, grid-side current amplitude and grid-side power factor angle; the input-side parameters include: input voltage angle frequency; The calculating the input side target power factor angle according to the feedforward compensation control parameter comprises: Substituting the feedforward compensation control parameter into the input side power factor angle calculation formula for calculation, the input side target power factor angle is obtained.

[0015] In some feasible embodiments, the input side power factor angle calculation formula is: ; in, is the input side power factor angle, is the filter capacitance, is the input voltage angular frequency, is the grid-side voltage amplitude, is the grid-side current amplitude, is the grid-side power factor angle.

[0016] Through the above technical scheme, the method distinguishes the input side power factor from the grid side power factor, calculates the target power factor angle of the input side when the grid side power factor reaches 1 according to the filter parameters, the grid side parameters and the input side parameters, and compensates the actual power factor angle of the input side according to the target power factor angle of the input side to compensate for the influence of the filter on the grid side power factor angle.

[0017] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 It is a flow chart of a converter power factor feedforward compensation control method provided by an embodiment of the present invention; Figure 2 is a topological diagram of a feedforward compensation control circuit provided by an embodiment of the present invention; Figure 3 is a single-phase equivalent circuit diagram provided by one embodiment of the present invention; Figure 4 It is a grid-side and input-side voltage and current phasor diagram provided by one embodiment of the present invention; Figure 5 It is a block diagram of a converter power factor feedforward compensation control device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0019] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0020] The existing grid-side power factor control method of the converter lacks the real-time detection function of the voltage and current parameters before and after the filter. When the unit converter performs power factor control, the influence of the grid-side filter inductance and capacitance, voltage and current parameters on the power factor angle is not considered. The existence of the grid-side filter will cause the phase difference of the input current before and after the filter, and the phase difference is affected by many factors such as the filter parameters and the input voltage amplitude. This will lead to a decrease in the input power factor. The existing grid-side power factor control method can only control the input side current of the converter to be consistent with the grid voltage phase, and fails to achieve real-time and accurate control of the grid-side power factor. In view of the control deviation problem existing in the current wind turbine converter, a wind turbine converter power factor feedforward compensation control method is proposed.

[0021] The converter power factor feedforward compensation control method of the present application can calculate the current phase difference before and after the grid-side filter according to the input voltage and current values, and adjust the target value of the input phase shift angle in real time accordingly, so as to achieve effective control of the input power factor under any working condition. It ensures that the input power factor is always close to 1, so as to ensure high grid-side power quality and accurate control.

[0022] Figure 1 FIG. 1 is a flow chart of a converter power factor feedforward compensation control method provided by an embodiment of the present invention. Figure 1 As shown, an embodiment of the present invention provides a converter power factor feedforward compensation control method, the method comprising: S1: Obtain feedforward compensation control parameters, the feedforward compensation control parameters including: filter parameters, grid side parameters and input side parameters. In some feasible embodiments, filter parameters can be obtained from grid side filters, some grid side parameters can be collected from grid side lines, and input side parameters can be collected from input side lines.

[0023] In some other feasible embodiments, the above parameters may also be obtained from a control system.

[0024] S2: Calculate the input side target power factor angle according to the feedforward compensation control parameter.

[0025] In some feasible embodiments, the filter parameters include filter capacitance, the grid-side parameters include: grid-side voltage amplitude, grid-side current amplitude and grid-side power factor angle; the input-side parameters include: input voltage angle frequency; The calculating the input side target power factor angle according to the feedforward compensation control parameter comprises: Substituting the feedforward compensation control parameter into the input side power factor angle calculation formula for calculation, the input side target power factor angle is obtained.

[0026] In some feasible embodiments, the input side power factor angle calculation formula is: ; in, is the input side power factor angle, is the filter capacitance, is the input voltage angular frequency, is the grid-side voltage amplitude, is the grid-side current amplitude, is the grid-side power factor angle.

[0027] This application adopts grid-side filter feedforward compensation control. Based on the currently commonly used control strategy, the influence of voltage and current changes and inductance and capacitance parameters on the power factor is taken into account, and a feedforward compensation function is added to effectively control the grid-side input power factor in real time to ensure real-time detection of grid-side voltage and current phase under various working conditions, maintain a high input power factor of the matrix converter, and achieve accurate control of the power factor. The topology diagram is shown in FIG. Figure 2 As shown, the grid-side voltage and current are filtered by the RLC filter circuit and then output to the converter circuit for adjustment. After the converter power factor feedforward compensation control method of the present application is introduced, it is necessary to collect the voltage amplitude and current amplitude on the grid side, and then obtain the filter capacitance from the filter circuit, and then calculate the compensation power factor angle in combination with the power factor angle on the grid side and the input voltage angle frequency. The compensation power factor angle is the input side power factor angle, and then a modulation strategy is formulated based on the input side power factor angle to control the converter to perform compensation regulation according to the modulation strategy.

[0028] Since a grid-side filter is added to the wind turbine converter, the existence of the filter will cause a certain deviation between the grid-side power factor angle and the input power factor angle. In order to accurately achieve controllable grid-side power factor, a feedforward compensation is required. The basic theory of compensation is to establish a mathematical model of the circuit equivalence relationship between the grid side and the input side of the front-stage filter, thereby determining the calculation formula for the input-side power factor angle.

[0029] In some feasible embodiments, the input side power factor angle calculation formula is constructed in the following manner: First, construct an equivalent single-phase circuit of the power grid, grid-side filter and converter circuit, such as Figure 3 As shown. The filter can be equivalent to a series inductor and capacitor The equivalent single-phase grid-side voltage is filtered by the filter to obtain the equivalent single-phase input-side voltage.

[0030] Then, the voltage and current phasor diagrams of the grid side and the input side are constructed according to the constructed equivalent single-phase circuit. According to the equivalent single-phase circuit, the phasor diagrams of the grid side voltage and current, capacitor current and input current are made, such as Figure 4 As shown, is the capacitor current, is the input current amplitude, is the grid-side current amplitude, is the grid-side voltage amplitude. Assuming that the grid-side current amplitude and the grid-side voltage amplitude are zero degrees, the parallel components of the input-side current amplitude decomposed along the grid-side current amplitude direction are: , , the vertical component decomposed along the direction perpendicular to the grid-side current amplitude is , ; The capacitor current of the front filter affects the power factor angle on the grid side. The capacitor current leads the grid phase voltage by 90°, which increases the phase shift angle between the input current and the grid voltage.

[0031] Then, expressions of each voltage and current are determined according to the voltage and current vector diagram. In some feasible embodiments, the expressions determined according to the voltage and current vector diagram include: an equivalent single-phase grid-side voltage expression, an equivalent single-phase grid-side current expression, and an equivalent single-phase input-side current expression; The equivalent single-phase grid-side voltage expression is: ; The equivalent single-phase grid-side current expression is: ; The equivalent single-phase input side current expression is:

[0032] in, is the equivalent single-phase grid-side voltage, is the grid-side voltage amplitude, is the equivalent single-phase grid-side current, is the grid-side current amplitude, is the equivalent single-phase input side current, is the input current amplitude, is the phase angle of the equivalent single-phase grid-side voltage; is the phase angle of the equivalent single-phase grid-side current; is the grid-side power factor angle, is the phase angle of the equivalent single-phase input current.

[0033] Then, a grid-side state equation is constructed. In the embodiment of the present application, according to Kirchhoff's voltage and current laws, the expression of the grid-side state equation can be obtained: ; ; in, is the filter capacitance, is the input voltage angular frequency, is the equivalent single-phase grid-side voltage, is the equivalent single-phase input side voltage, is the equivalent single-phase grid-side current, is the grid-side filter inductance, is the equivalent single-phase input side current, Is an imaginary unit.

[0034] Finally, the mathematical model corresponding to the input side power factor angle is obtained based on the grid side state equation and the expressions of each voltage and current. The grid side state equation is further deformed according to the expressions of each voltage and current to obtain the input side power factor angle calculation formula.

[0035] S3: Compensating the actual power factor angle on the input side according to the target power factor angle on the input side.

[0036] In some feasible embodiments, compensating the input side actual power factor angle according to the input side target power factor angle includes: Determine whether the actual power factor angle on the input side is equal to the target power factor angle on the input side; If the actual power factor angle on the input side is equal to the target power factor angle on the input side, no compensation is required; If the actual power factor angle on the input side is greater than the target power factor angle on the input side, a reduction adjustment strategy is implemented for the actual power factor angle on the input side; If the actual power factor angle on the input side is less than the target power factor angle on the input side, an increasing adjustment strategy is executed on the actual power factor angle on the input side.

[0037] According to the above technical means, the grid-side power factor angle can be set as needed, for example, it can be set to 0°, 30°, etc., and then the grid-side power factor angle and the feedforward compensation control parameter are substituted into the input-side power factor angle calculation formula to obtain the input-side target power factor angle, and the input-side target power factor angle is used as the adjustment amount of space vector modulation to achieve accurate control of the grid-side power factor.

[0038] The method of the present application establishes the filter input and output side models, derives the grid-side power factor angle and the filter, sets the relationship between the power factor angles, and performs dynamic feedforward compensation on the power factor according to the derived results. On the one hand, it is beneficial to improve the control performance of the converter and achieve accurate control of the power factor; on the other hand, the proposed control strategy can ensure high grid-side power quality, as well as the safety, reliability and long service life of electrical components.

[0039] A second aspect of the present application provides a converter power factor feedforward compensation control device, such as Figure 5 As shown, the converter power factor feedforward compensation control device includes: A parameter acquisition unit, used to acquire feedforward compensation control parameters, wherein the feedforward compensation control parameters include: filter parameters, grid-side parameters and input-side parameters; A calculation unit, used for calculating the input side target power factor angle according to the feedforward compensation control parameter; An execution unit is used to compensate the actual power factor angle on the input side according to the target power factor angle on the input side.

[0040] The device distinguishes the input side power factor from the grid side power factor, and calculates the target power factor angle of the input side when the grid side power factor reaches 1 based on the filter parameters, the grid side parameters and the input side parameters. The actual power factor angle of the input side is compensated based on the target power factor angle of the input side to compensate for the influence of the filter on the grid side power factor angle.

[0041] In some feasible embodiments, the filter parameters include filter capacitance, the grid-side parameters include: grid-side voltage amplitude, grid-side current amplitude and grid-side power factor angle; the input-side parameters include: input voltage angle frequency; The calculating the input side target power factor angle according to the feedforward compensation control parameter comprises: Substituting the feedforward compensation control parameter into the input side power factor angle calculation formula for calculation, the input side target power factor angle is obtained.

[0042] In some feasible embodiments, the input side power factor angle calculation formula is: ; in, is the input side power factor angle, is the filter capacitance, is the input voltage angular frequency, is the grid-side voltage amplitude, is the grid-side current amplitude, is the grid-side power factor angle.

[0043] The embodiment of the present invention further provides a machine-readable storage medium having computer program instructions stored thereon, and the computer program instructions, when executed by a processor, implement the above-mentioned converter power factor feedforward compensation control method.

[0044] Those skilled in the art will understand that all or part of the steps in the method for implementing the above-mentioned embodiments can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for making a single-chip microcomputer, a chip or a processor execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0045] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, the technical scheme of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0046] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A converter power factor feedforward compensation control method, characterized in that: The converter power factor feedforward compensation control method comprises: Obtaining feedforward compensation control parameters, wherein the feedforward compensation control parameters include: filter parameters, grid side parameters, and input side parameters; Calculating the input side target power factor angle according to the feedforward compensation control parameter; The actual power factor angle on the input side is compensated according to the target power factor angle on the input side.

2. The converter power factor feedforward compensation control method according to claim 1, characterized in that: The filter parameters include filter capacitance, the grid-side parameters include: grid-side voltage amplitude, grid-side current amplitude and grid-side power factor angle; the input-side parameters include: input voltage angle frequency; The calculating the input side target power factor angle according to the feedforward compensation control parameter comprises: Substituting the feedforward compensation control parameter into the input side power factor angle calculation formula for calculation, the input side target power factor angle is obtained.

3. The converter power factor feedforward compensation control method according to claim 2, characterized in that: The input side power factor angle calculation formula is: ； in, is the input side power factor angle, is the filter capacitance, is the input voltage angular frequency, is the grid-side voltage amplitude, is the grid-side current amplitude, is the grid-side power factor angle.

4. The converter power factor feedforward compensation control method according to claim 2, characterized in that: The input side power factor angle calculation formula is constructed as follows: Construct an equivalent single-phase circuit of the power grid, grid-side filter and converter circuit; Construct voltage and current vector diagrams on the grid side and input side according to the constructed equivalent single-phase circuit; Determine expressions of each voltage and current according to the voltage-current vector diagram; Construct the grid-side state equation; According to the grid-side state equation and the expressions of various voltages and currents, the mathematical model corresponding to the input-side power factor angle is obtained.

5. The converter power factor feedforward compensation control method according to claim 4, characterized in that: The expressions determined according to the voltage-current vector diagram include: an equivalent single-phase grid-side voltage expression, an equivalent single-phase grid-side current expression, and an equivalent single-phase input-side current expression; The equivalent single-phase grid-side voltage expression is: ； The equivalent single-phase grid-side current expression is: ； The equivalent single-phase input side current expression is: in, is the equivalent single-phase grid-side voltage, is the grid-side voltage amplitude, is the equivalent single-phase grid-side current, is the grid-side current amplitude, is the equivalent single-phase input side current, is the input current amplitude, is the phase angle of the equivalent single-phase grid-side voltage; is the phase angle of the equivalent single-phase grid-side current; is the grid-side power factor angle, is the phase angle of the equivalent single-phase input current.

6. The converter power factor feedforward compensation control method according to claim 4, characterized in that: The grid-side state equation includes: ； ； in, is the filter capacitance, is the input voltage angular frequency, is the equivalent single-phase grid-side voltage, is the equivalent single-phase input side voltage, is the equivalent single-phase grid-side current, is the grid-side filter inductance, is the equivalent single-phase input side current, Is an imaginary unit.

7. The converter power factor feedforward compensation control method according to claim 1, characterized in that: Compensating the actual power factor angle on the input side according to the target power factor angle on the input side includes: Determine whether the actual power factor angle on the input side is equal to the target power factor angle on the input side; If the actual power factor angle on the input side is equal to the target power factor angle on the input side, no compensation is required; If the actual power factor angle on the input side is greater than the target power factor angle on the input side, a reduction adjustment strategy is implemented for the actual power factor angle on the input side; If the actual power factor angle on the input side is less than the target power factor angle on the input side, an increasing adjustment strategy is executed on the actual power factor angle on the input side.

8. A converter power factor feedforward compensation control device, characterized in that: The converter power factor feedforward compensation control device comprises: A parameter acquisition unit, used to acquire feedforward compensation control parameters, wherein the feedforward compensation control parameters include: filter parameters, grid-side parameters and input-side parameters; A calculation unit, used for calculating the input side target power factor angle according to the feedforward compensation control parameter; An execution unit is used to compensate the actual power factor angle on the input side according to the target power factor angle on the input side.

9. The converter power factor feedforward compensation control device according to claim 8, characterized in that: The filter parameters include filter capacitance, the grid-side parameters include: grid-side voltage amplitude, grid-side current amplitude and grid-side power factor angle; the input-side parameters include: input voltage angle frequency; The calculating the input side target power factor angle according to the feedforward compensation control parameter comprises: Substituting the feedforward compensation control parameter into the input side power factor angle calculation formula for calculation, the input side target power factor angle is obtained.

10. The converter power factor feedforward compensation control device according to claim 9, characterized in that: The input side power factor angle calculation formula is: ； in, is the input side power factor angle, is the filter capacitance, is the input voltage angular frequency, is the grid-side voltage amplitude, is the grid-side current amplitude, is the grid-side power factor angle.

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