Direct-drive permanent magnet wind power generation system

Abstract

The application provides a direct-drive permanent-magnet wind power generation system, which has the characteristics of comprising a wind turbine, a first permanent-magnet synchronous generator for converting kinetic energy of the wind turbine into first three-phase electricity, a first rectifier for converting the first three-phase electricity into first direct current, a flywheel mechanical device, a second permanent-magnet synchronous generator for converting kinetic energy of the flywheel mechanical device into second three-phase electricity, a second rectifier for converting the second three-phase electricity into second direct current, a third rectifier for converting the first direct current and the second direct current into third three-phase electricity, and a power fluctuation control device, wherein the power fluctuation control device is used for controlling the third rectifier according to a modulation signal, so that the voltage of the third three-phase electricity is constant. In summary, the method can effectively improve the grid-connected active power fluctuation of the direct-drive permanent-magnet wind power generator caused by the wind speed fluctuation of natural wind.

Description

Technical Field

[0001] This invention relates to the field of flywheel energy storage control strategies, and more specifically to a direct-drive permanent magnet wind power generation system. Background Technology

[0002] With the development of global industry, the requirements for power quality are becoming increasingly stringent. Modern power supply is characterized by its large scale and continuity. Wind energy is the fastest-growing clean energy source among renewable energy sources and also has the greatest potential for large-scale development and commercialization. However, wind power generation is greatly affected by wind speed; fluctuations in wind speed lead to fluctuations in active power on the grid side, with the amplitude of these fluctuations generally following the changes in wind speed. Therefore, introducing high-efficiency, large-capacity energy storage systems into the power grid becomes crucial. Flywheel energy storage systems have high energy density, high efficiency, and fast response speed, effectively solving the problem of active power fluctuations caused by wind speed variations.

[0003] However, the existing control strategy for the outer ring flywheel energy storage system still suffers from the problem of fluctuations in the active power of the direct-drive permanent magnet wind turbine connected to the grid due to natural wind speed fluctuations. Summary of the Invention

[0004] This invention is made to solve the above-mentioned problems, and its purpose is to provide a direct-drive permanent magnet wind power generation system.

[0005] This invention provides a direct-drive permanent magnet wind power generation system, characterized by comprising: a wind turbine, a first permanent magnet synchronous generator for converting the kinetic energy of the wind turbine into a first three-phase electricity, a first rectifier for converting the first three-phase electricity into a first direct current (DC), a flywheel mechanism, a second permanent magnet synchronous generator for converting the kinetic energy of the flywheel mechanism into a second three-phase electricity, a second rectifier for converting the second three-phase electricity into a second DC, a third rectifier for converting a third three-phase electricity into the first DC and second DC, and a power fluctuation control device. The power fluctuation control device is used to control the third rectifier according to a modulation signal to keep the voltage of the third three-phase electricity constant. It includes: a data acquisition module for acquiring the real-time power of the first permanent magnet synchronous generator, the DC-side current and DC-side voltage of the first rectifier, and the second... The system comprises the following modules: a three-phase (A, B, C) current and rotor angle of a permanent magnet synchronous generator; a first calculation module storing a preset rated power, used to calculate the difference between the real-time power and the rated power as a first error value; a total power calculation module, used to calculate the product of the DC-side current and the DC-side voltage as the total DC-side power; a second calculation module, used to calculate the difference between the first error value and the total DC-side power as a second error value; a first PI control module, used to process the second error value to obtain the q-axis reference current; a dq current generation module, including a PARK converter, used to calculate the q-axis current and d-axis current based on the three-phase (A, B, C) current and the rotor angle of the generator; a third calculation module, used to calculate the difference between the q-axis reference current and the q-axis current as a third error value; and a second PI control module, used to process the third error value to obtain the q-axis control voltage. The fourth calculation module stores a preset d-axis reference current with a value of 0, and is used to calculate the difference between the d-axis reference current and the d-axis current as the fourth error value. The third PI control module processes the fourth error value to obtain the d-axis control voltage. The current generation module, including an inverse PARK converter, is used to control the voltage according to the d-axis. q-axis control voltage The three-phase current is calculated based on the motor rotor angle. ; Modulation signal generation module, used to generate signals based on three-phase current Generate a modulated signal.

[0006] The direct-drive permanent magnet wind power generation system provided by the present invention may also have the following features: wherein the modulation signal is an SPWM control signal, the third rectifier is composed of 6 IGBT transistors, and the conduction and shutdown of each IGBT transistor are controlled by the SPWM control signal.

[0007] The direct-drive permanent magnet wind power generation system provided by this invention may also have the following feature: wherein the IGBT transistor is an insulated-gate bipolar transistor, and its default parameter is set to a protection resistor. Open circuit resistance .

[0008] The direct-drive permanent magnet wind power generation system provided by this invention may also have the following feature: wherein the rated power is 1.5MW.

[0009] The direct-drive permanent magnet wind power generation system provided by the present invention may also have the following features: wherein the first PI control module is a PI controller, and the default value of the internal parameters of the PI controller is set to P=0.5 and I=20.

[0010] The direct-drive permanent magnet wind power generation system provided by the present invention may also have the following features: the second PI control module and the third PI control module are both PI controllers, and their internal parameters are set to default values ​​of P=1 and I=10.

[0011] The direct-drive permanent magnet wind power generation system provided by the present invention may also have the following features: it further includes a transformer for processing the third phase electricity and then connecting it to the power grid.

[0012] The role and effect of invention

[0013] According to the direct-drive permanent magnet wind power generation system of the present invention, by acquiring the real-time power of the first permanent magnet synchronous generator, the DC-side current and DC-side voltage of the first rectifier, and the ABC three-phase current and rotor angle of the second permanent magnet synchronous generator through a power fluctuation control device, a modulation signal capable of controlling the rated power is calculated. This smooths the fluctuations in the grid-connected active power of the direct-drive permanent magnet wind power generation system caused by wind speed fluctuations, unlike existing speed outer-loop control, achieving a better fluctuation smoothing effect. Therefore, the direct-drive permanent magnet wind power generation system of the present invention can effectively improve the grid-connected active power fluctuations of the direct-drive permanent magnet wind turbine generator caused by natural wind speed fluctuations. Attached Figure Description

[0014] Figure 1 This is a block diagram of a direct-drive permanent magnet wind power generation system in an embodiment of the present invention;

[0015] Figure 2 This is a block diagram of the power fluctuation control device in an embodiment of the present invention;

[0016] Figure 3 This is a schematic diagram of the working process of the power fluctuation control device in an embodiment of the present invention. Detailed Implementation

[0017] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, will specifically illustrate the direct-drive permanent magnet wind power generation system of the present invention.

[0018] Figure 1 This is a block diagram of a direct-drive permanent magnet wind power generation system in an embodiment of the present invention.

[0019] like Figure 1 As shown, the direct-drive permanent magnet wind power generation system 1 includes a wind turbine 11, a first permanent magnet synchronous generator 12, a first rectifier 13, a flywheel mechanical device 14, a second permanent magnet synchronous generator 15, a second rectifier 16, a third rectifier 17, a transformer 19, and a power fluctuation control device 20.

[0020] The wind turbine 11 is used to convert wind energy into kinetic energy.

[0021] The first permanent magnet synchronous generator 12 is connected to the shaft of the wind turbine 11 and is used to convert the kinetic energy of the wind turbine 11 into the first three-phase electricity.

[0022] The first rectifier 13 is connected to the first permanent magnet synchronous generator 12 and is used to convert the first three-phase electricity into the first direct current.

[0023] The flywheel mechanism 14 is used to store and release kinetic energy.

[0024] The second permanent magnet synchronous generator 15 is connected to the flywheel mechanical device 14 shaft and is used to convert the kinetic energy of the flywheel mechanical device 14 into second three-phase electricity.

[0025] The second rectifier 16 is connected to the second permanent magnet synchronous generator 15 and is used to convert the second three-phase electricity into the second direct current.

[0026] The third rectifier 17 is connected to the first rectifier 13 and the second rectifier 16 respectively, and is used to convert the third three-phase power into the first DC power and the second DC power.

[0027] In this embodiment, a capacitor is provided at the DC bus between the first rectifier 13 and the third rectifier 17.

[0028] Transformer 19 is used to process the third phase of electricity before connecting it to the power grid.

[0029] The power fluctuation control device 20 is connected to the first permanent magnet synchronous generator 12, the first rectifier 13, the second permanent magnet synchronous generator 15 and the third rectifier 17 respectively, and is used to control the third rectifier 17 according to the modulation signal to keep the voltage of the third three-phase power constant.

[0030] The modulation signal is an SPWM control signal. The third rectifier 17 is composed of 6 IGBT transistors. The SPWM control signal controls the conduction and shutdown of each IGBT transistor. In this embodiment, the SPWM control signal finally flows into the gate (g) of the IGBT transistors of the third rectifier 17.

[0031] The IGBT transistor is an insulated gate bipolar transistor, and its default parameter is set to a protection resistor. Open circuit resistance .

[0032] Figure 2 This is a block diagram of the power fluctuation control device in an embodiment of the present invention.

[0033] like Figure 2 As shown, the power fluctuation control device 20 includes a data acquisition module 201, a first calculation module 202, a total power calculation module 203, a second calculation module 204, a first PI control module 205, a dq current generation module 206, a third calculation module 207, a second PI control module 208, a fourth calculation module 209, a third PI control module 210, a current generation module 211, a modulation signal generation module 212, and a general control module 213 that controls the above modules.

[0034] The data acquisition module 201 is used to acquire the real-time power of the first permanent magnet synchronous generator 12, the DC side current and DC side voltage of the first rectifier 13, and the ABC three-phase current and motor rotor angle of the second permanent magnet synchronous generator 15.

[0035] The first calculation module 202 stores a preset rated power and is used to calculate the difference between the real-time power and the rated power as a first error value, wherein the rated power is 1.5MW.

[0036] The total power calculation module 203 is used to calculate the total DC power by multiplying the DC side current and the DC side voltage.

[0037] The second calculation module 204 is used to calculate the difference between the first error value and the total power on the DC side as the second error value.

[0038] The first PI control module 205 is used to process the second error value to obtain the q-axis reference current.

[0039] Among them, the first PI control module 205 is a PI controller, and the default internal parameters of the PI controller are set to P=0.5 and I=20.

[0040] The dq current generation module 206 includes a PARK converter, which is used to calculate the q-axis current and d-axis current based on the ABC three-phase currents and the motor rotor angle.

[0041] The third calculation module 207 is used to calculate the difference between the q-axis reference current and the q-axis current as the third error value.

[0042] The second PI control module 208 is used to process the third error value to obtain the q-axis control voltage. .

[0043] The fourth calculation module 209 stores a preset d-axis reference current with a value of 0, which is used to calculate the difference between the d-axis reference current and the d-axis current as the fourth error value.

[0044] The third PI control module 210 is used to process the fourth error value to obtain the d-axis control voltage. .

[0045] Among them, the second PI control module 208 and the third PI control module 210 are both PI controllers, and their internal parameters are set to default values ​​of P=1 and I=10.

[0046] The current generation module 211 includes an inverse PARK converter for controlling the voltage according to the d-axis. q-axis control voltage The three-phase current is calculated based on the motor rotor angle. .

[0047] The modulation signal generation module 212 is used to generate a modulation signal based on the three-phase current. Generate a modulated signal.

[0048] The main control module 213 stores the control program, which is used to control the operation of each module.

[0049] Figure 3 This is a schematic diagram of the working process of the power fluctuation control device in an embodiment of the present invention.

[0050] like Figure 3 As shown, the working process of the power fluctuation control device 20 includes the following steps:

[0051] Step S1: The data acquisition module 201 acquires the real-time power of the first permanent magnet synchronous generator 12.

[0052] In step S2, the first calculation module 202 calculates the difference between the real-time power and the rated power as the first error value.

[0053] Step S3: The data acquisition module 201 acquires the DC side current and DC side voltage of the first rectifier 13.

[0054] In step S4, the total power calculation module 203 uses the product of the DC side current and the DC side voltage as the total DC side power.

[0055] In step S5, the second calculation module 204 calculates the difference between the first error value and the total power on the DC side as the second error value.

[0056] In step S6, the first PI control module 205 processes the second error value to obtain the q-axis reference current.

[0057] Step S7: The data acquisition module 201 acquires the ABC three-phase currents and the rotor angle of the second permanent magnet synchronous generator 15.

[0058] In step S8, the dq current generation module 206 calculates the q-axis current and d-axis current based on the three-phase currents ABC and the motor rotor angle.

[0059] Step S9, the third calculation module 207 calculates the difference between the q-axis reference current and the q-axis current as the third error value.

[0060] In step S10, the second PI control module 208 processes the third error value to obtain the q-axis control voltage. .

[0061] Step S11, the fourth calculation module 209 calculates the difference between the d-axis reference current and the d-axis current as the fourth error value.

[0062] In step S12, the third PI control module 210 processes the fourth error value to obtain the d-axis control voltage. .

[0063] Step S13, the current generation module 211 controls the voltage according to the d-axis. q-axis control voltage The three-phase current is calculated based on the motor rotor angle. .

[0064] Step S14, the modulation signal generation module 212 generates the signal based on the three-phase current. Generate a modulated signal.

[0065] The role and effect of the embodiments

[0066] According to the direct-drive permanent magnet wind power generation system involved in this embodiment, the real-time power of the first permanent magnet synchronous generator, the DC-side current and DC-side voltage of the first rectifier, and the ABC three-phase current and rotor angle of the second permanent magnet synchronous generator are collected by a power fluctuation control device. A modulation signal that can control the rated power is then calculated, thereby smoothing the fluctuations in the grid-connected active power of the direct-drive permanent magnet wind power generation system caused by wind speed fluctuations. This method differs from existing speed outer-loop control and achieves a better fluctuation smoothing effect. In summary, this method can effectively improve the grid-connected active power fluctuations of direct-drive permanent magnet wind turbines caused by natural wind speed fluctuations.

[0067] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A direct-drive permanent magnet wind power generation system, characterized in that, include: The system includes a wind turbine, a first permanent magnet synchronous generator for converting the kinetic energy of the wind turbine into a first three-phase electricity, a first rectifier for converting the first three-phase electricity into a first direct current (DC), a flywheel mechanical device, a second permanent magnet synchronous generator for converting the kinetic energy of the flywheel mechanical device into a second three-phase electricity, a second rectifier for converting the second three-phase electricity into a second DC, a third rectifier for converting a third three-phase electricity into both the first DC and the second DC, and a power fluctuation control device. The power fluctuation control device is used to control the third rectifier according to the modulation signal to keep the voltage of the third three-phase power constant, including: The data acquisition module is used to acquire the real-time power of the first permanent magnet synchronous generator, the DC side current and DC side voltage of the first rectifier, and the ABC three-phase current and motor rotor angle of the second permanent magnet synchronous generator. The first calculation module stores a preset rated power and is used to calculate the difference between the real-time power and the rated power as a first error value. The total power calculation module is used to calculate the total DC power by multiplying the DC-side current and the DC-side voltage. The second calculation module is used to calculate the difference between the first error value and the total power on the DC side as the second error value; The first PI control module is used to process the second error value to obtain the q-axis reference current; The dq current generation module includes a PARK converter, which is used to calculate the q-axis current and d-axis current based on the ABC three-phase currents and the motor rotor angle. The third calculation module is used to calculate the difference between the q-axis reference current and the q-axis current as the third error value; The second PI control module is used to process the third error value to obtain the q-axis control voltage. ; The fourth calculation module stores a preset d-axis reference current with a value of 0, which is used to calculate the difference between the d-axis reference current and the d-axis current as the fourth error value. The third PI control module is used to process the fourth error value to obtain the d-axis control voltage. ; The current generation module includes an inverse PARK converter for controlling the voltage according to the d-axis. The q-axis control voltage The three-phase current is calculated based on the rotor angle of the motor. ; Modulation signal generation module, used to generate a modulation signal based on the three-phase current. The modulation signal is generated.

2. The direct-drive permanent magnet wind power generation system according to claim 1, characterized in that: in, The modulation signal is an SPWM control signal. The third rectifier consists of six IGBT transistors, and the SPWM control signal controls the conduction and shutdown of each IGBT transistor.

3. The direct-drive permanent magnet wind power generation system according to claim 2, characterized in that: in, The IGBT transistor is an insulated gate bipolar transistor, and its default parameter is set to a protection resistor. Open circuit resistance .

4. The direct-drive permanent magnet wind power generation system according to claim 1, characterized in that: in, The rated power is 1.5MW.

5. The direct-drive permanent magnet wind power generation system according to claim 1, characterized in that: in, The first PI control module is a PI controller, and the default internal parameters of the PI controller are set to P=0.5 and I=20.

6. The direct-drive permanent magnet wind power generation system according to claim 1, characterized in that: in, Both the second PI control module and the third PI control module are PI controllers, and their internal parameters are set to default values ​​of P=1 and I=10.

7. The direct-drive permanent magnet wind power generation system according to claim 1, characterized in that, Also includes: A transformer is used to process the third three-phase electricity before connecting it to the power grid.

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