Wind power generation unit system and topological parameter optimization and control design method thereof

Abstract

According to the wind power generation unit system and the topological parameter optimization and control design method thereof, on one hand, rated parameters are determined, then the value ranges of direct current side capacitance, commutation inductance, filter capacitance and damping resistance and the voltage level of the direct current side are calculated and determined, and then machine side and network side current converter control systems are designed; finally, simulation software and a hardware platform are used for conducting simulation verification optimization. On the other hand, a wind power generation unit system topology composed of a wind turbine, a permanent magnet synchronous generator, a back-to-back full-power converter, a filter and a boosting transformer is constructed, and wind energy-mechanical energy-electric energy conversion, processing and grid connection are cooperatively achieved. By accurately calculating system parameters, optimizing converter design, reducing energy loss and cooperating with control system design, parameters of core devices of all parts can be reasonably configured, more excellent control performance is achieved, and therefore the conversion efficiency, the electric energy quality and the system stability of a power generation unit are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and in particular relates to a wind power generation unit system and a topology parameter optimization and control design method thereof. Background Art

[0002] With growing global energy demand and increasingly prominent environmental issues, wind power generation, as a clean and renewable energy source, is gaining increasing attention. Wind power generation systems primarily consist of wind turbines, generators, power converters (inverters), transformers, and control systems. Currently, wind power generation units are primarily categorized as doubly-fed wind turbines and permanent magnet direct-drive wind turbines, corresponding to Type III and Type IV wind turbines in the IEEE standard, respectively.

[0003] Direct-drive permanent magnet synchronous wind turbines (PMSGs) are gaining increasing attention due to their high reliability, low maintenance costs, and high efficiency. A direct-drive PMSG wind turbine typically consists of a wind turbine, a PMSG generator, a back-to-back full-power converter, a filter, and a step-up transformer. The back-to-back full-power converter converts the variable-frequency AC power output from the generator to grid-frequency AC power, enabling grid connection.

[0004] However, existing direct-drive permanent magnet synchronous wind turbines still suffer from several issues in parameter design and control strategies, such as low converter efficiency, large DC voltage fluctuations, and insufficient system stability during grid faults. Therefore, a more comprehensive control method and parameter optimization design approach are needed to improve the efficiency, stability, and reliability of direct-drive permanent magnet synchronous wind turbines. Summary of the Invention

[0005] In view of this, the present invention provides a wind power generation unit system and its topology parameter optimization and control design method, which can reasonably configure the parameters of the core components of each part and achieve better control performance, thereby improving the conversion efficiency, power quality and system stability of the power generation unit, and at the same time enhancing the system's adaptability under power grid failures.

[0006] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for optimizing and controlling topological parameters of a wind power generation unit system, comprising:

[0008] Determine the rated parameters of the wind power unit system;

[0009] Calculate the DC side capacitance value of the converter based on the rated parameters;

[0010] Determine the value range of the commutation inductance on the AC side of the converter based on the rated parameters;

[0011] Determine the value range of the filter capacitor based on the rated parameters;

[0012] Determine the damping resistance value of the filter based on the rated parameters;

[0013] Determine the DC side voltage level based on rated parameters;

[0014] Determine the control systems of the machine-side converter and grid-side converter of the wind power generation unit system;

[0015] Based on the DC side capacitance, damping resistor value, DC side voltage level, and the AC side commutation inductance and filter capacitance of the converter determined within their respective value ranges, simulation software is used to verify and optimize the control strategy of each parameter and control system.

[0016] Based on the optimized system parameters, the experimental system built on the hardware platform is used for re-verification. After the verification is passed, the final system parameters and control system design are obtained.

[0017] Furthermore, the calculation expression of the DC side capacitance value is as follows:

[0018]

[0019] Where, is the DC side capacitance value; is the rated output power; To keep time; is the energy output efficiency; is the DC side voltage value.

[0020] Furthermore, the value range of the commutation inductance is determined according to the following formula:

[0021]

[0022]

[0023] Where, is the commutation inductor; is the per-unit value of the harmonic voltage amplitude at the carrier frequency; is the DC side voltage value; is the permissible AC current pulsation amplitude; is the AC current rating; is the allowable voltage drop; is the line voltage; is the angular frequency, is the switching frequency.

[0024] Furthermore, the value range of the filter capacitor is determined according to the following formula:

[0025]

[0026] Where, is the filter capacitor; is the switching frequency; is the commutation inductor; is the fundamental frequency.

[0027] Furthermore, the calculation expression of the damping resistance value is as follows:

[0028]

[0029] Where, is the damping resistance value; is the commutation inductance value; is the filter capacitor.

[0030] Furthermore, the DC side voltage level is determined according to the range of the DC side voltage value, and the range of the DC side voltage value is determined according to the following formula:

[0031]

[0032] Where, is the DC voltage value, is the effective value of the AC phase voltage, is the maximum modulation ratio.

[0033] Furthermore, the grid-side converter adopts adaptive reactive component decoupling control, which realizes decoupling control of active component and reactive component based on dq coordinate transformation, wherein the active component is used to stabilize the DC side voltage; the reactive component is used to control the AC side voltage amplitude or reactive power; when a fault occurs in the power grid, the reactive current reference value is dynamically adjusted according to the low voltage ride-through curve, and the active output is limited at the same time.

[0034] Furthermore, the generator-side converter adopts maximum power point tracking control.

[0035] Furthermore, a Chopper protection circuit is configured on the DC side of the wind power generation unit system.

[0036] In a second aspect, the present invention provides a wind power generation unit system topology, wherein system parameters and a control system are determined based on the wind power generation unit system topology parameter optimization and control design method according to the first aspect, including:

[0037] Wind turbines, permanent magnet synchronous generators, back-to-back full-power converters, filters and step-up transformers;

[0038] Wind turbines are used to convert wind energy into mechanical energy;

[0039] Permanent magnet synchronous generator is used to convert mechanical energy into AC electrical energy;

[0040] The back-to-back full-power converter is used to convert AC power into AC power that matches the grid frequency, phase, and amplitude. The back-to-back full-power converter includes a generator-side converter and a grid-side converter, both of which use a two-level voltage source converter.

[0041] The filter is used to filter out the harmonic components in the output current of the back-to-back full-power converter;

[0042] The step-up transformer is used to step up the AC power output by the back-to-back full-power converter to the voltage level required by the power grid.

[0043] In summary, the present invention provides a wind power generation unit system and its topology parameter optimization and control design method. On the one hand, by determining the rated parameters, then calculating and determining the DC side capacitor, commutation inductor, filter capacitor and damping resistor value range, DC side voltage level, and then designing the machine side and grid side converter control system, and finally using simulation software and hardware platform to perform simulation verification and optimization respectively. On the other hand, a wind power generation unit system topology consisting of a wind turbine, a permanent magnet synchronous generator, a back-to-back full-power converter, a filter, and a step-up transformer is constructed to collaboratively realize wind energy-mechanical energy-electrical energy conversion, processing and grid connection. The present invention can reasonably configure the parameters of the core components of each part and achieve more excellent control performance by accurately calculating system parameters, optimizing converter design, reducing energy loss, and coordinating control system design, thereby improving the conversion efficiency, power quality and system stability of the power generation unit, and enhancing the system's adaptability under power grid failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 A schematic diagram of a wind power generation unit system provided by an embodiment of the present invention;

[0046] Figure 2 A topological diagram of a two-level VSC wind power generation unit model provided in an embodiment of the present invention;

[0047] Figure 3 The overall structure diagram of the wind turbine generator control system provided by the embodiment of the present invention;

[0048] Figure 4 A schematic diagram of an adaptive reactive component decoupling control system provided by an embodiment of the present invention;

[0049] Figure 5 A grid-side converter fault ride-through control diagram provided by an embodiment of the present invention;

[0050] Figure 6 A steady-state operation control diagram of the generator-side converter provided in an embodiment of the present invention;

[0051] Figure 7 A schematic diagram of the topology of a large-scale wind power station provided by an embodiment of the present invention;

[0052] Figure 8 A schematic diagram of a wind power generation unit connected to the grid according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purposes, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0054] See also Figure 1 , an embodiment of the present invention provides a wind power generation unit system, comprising:

[0055] Wind turbines, permanent magnet synchronous generators, back-to-back full-power converters, filters and step-up transformers;

[0056] Wind turbines are used to convert wind energy into mechanical energy;

[0057] Permanent magnet synchronous generator is used to convert mechanical energy into AC electrical energy;

[0058] The back-to-back full-power converter is used to convert AC power into AC power that matches the grid frequency, phase, and amplitude. The back-to-back full-power converter includes a generator-side converter and a grid-side converter, both of which use a two-level voltage source converter.

[0059] The filter is used to filter out the harmonic components in the output current of the back-to-back full-power converter;

[0060] The step-up transformer is used to step up the AC power output by the back-to-back full-power converter to the voltage level required by the power grid.

[0061] It should be noted that the wind turbine simulates wind energy capture based on parameters such as wind speed, air density, rotor radius, and wind energy conversion efficiency coefficient, outputting mechanical torque to the permanent magnet synchronous generator. The back-to-back full-power converter is a two-level VSC (voltage source converter) type, connecting two AC lines with different frequencies and tracking the maximum to maximize output. The generator-side converter achieves maximum power tracking of wind power by tracking the optimal electromagnetic torque, while the grid-side converter establishes a stable DC voltage to ensure stable power output. The filter uses an RC (resistor-capacitor) filter, and the voltage is finally boosted by a step-up transformer before being connected to the grid.

[0062] The topology of the two-level VSC wind power generation unit model is as follows: Figure 2 As shown in the figure, the two-level VSC back-to-back full-power converter is a core component for achieving efficient power conversion and stable transmission in wind power generation systems. It consists of a generator-side converter and a grid-side converter connected back-to-back via a DC bus. It adopts a two-level voltage source topology and uses IGBTs (Insulated Gate Bipolar Transistors) as power switching devices. During operation, the generator-side converter uses PWM (Pulse Width Modulation) control to rectify the generator output AC power and adopts a maximum power point tracking control strategy to maximize wind energy capture. The grid-side converter inverts DC power into AC power that matches the grid frequency, phase, and amplitude. By decoupling active and reactive power, it stabilizes the DC bus voltage and achieves reactive power compensation. At the same time, combined with designs such as the DC-side chopper protection circuit, it can effectively respond to grid faults and ensure safe system operation. It is widely used in direct-drive permanent magnet synchronous wind power generation systems to achieve reliable connection and power exchange between the power generation unit and the grid.

[0063] This embodiment provides a wind power generation unit system whose parameter design mainly includes two parts: the parameter design of the AC side commutation inductor and filter capacitor, and the parameter design of the DC side capacitor and voltage selection. For the former, the parameter design method is basically the same as that of the photovoltaic power generation unit, and it is necessary to consider the current ripple amplitude, inductor voltage drop, filter capacitor reactive absorption, resonant frequency, etc.

[0064] In view of the system parameter and control system design of a wind power generation unit system proposed in the above embodiment, this embodiment provides a wind power generation unit system topology parameter optimization and control design method, including:

[0065] Step 1: Determine the rated parameters of the wind power unit system.

[0066] It should be noted that rated parameters refer to a series of standard parameters specified in the design when the wind power generation unit is operating normally and stably, including but not limited to rated power, rated voltage, rated current, rated speed, etc.

[0067] Step 2: Calculate the DC side capacitance value of the converter based on the rated parameters.

[0068] It's important to note that DC-side capacitors are energy storage elements on the DC side of the converter, used to stabilize DC voltage and buffer energy fluctuations. Calculating the capacitance value based on rated parameters (such as rated power and allowable DC voltage fluctuation range) ensures DC voltage stability under various operating conditions and prevents system damage from sudden voltage fluctuations.

[0069] Step 3: Determine the value range of the commutation inductance on the AC side of the converter based on the rated parameters.

[0070] It's important to note that the commutation inductor, located on the AC side of the converter, primarily functions to suppress sudden current fluctuations, smooth the current waveform, and reduce harmonic content. Determining its value range based on rated parameters (such as rated current, allowable current ripple, and system operating frequency) ensures the quality of the converter's output current, improves power conversion efficiency, and minimizes interference with the power grid.

[0071] Step 4: Determine the filter capacitor value range based on the rated parameters.

[0072] It's important to note that filters are used to remove harmonics from the converter's output current, improving power quality. Filter capacitors are key components of filters, and their value affects the filter's ability to suppress harmonics of varying frequencies. Determining the value range based on rated parameters (such as system rated voltage, current, and harmonic frequency distribution) allows the filter to more effectively filter harmonics, ensuring that the output power meets grid access standards.

[0073] Step 5: Determine the filter's damping resistor value based on the rated parameters.

[0074] It's important to note that damping resistors suppress resonance in filters, preventing them from resonating at specific frequencies and potentially causing system instability or component damage. Calculating the damping resistor value based on rated parameters (such as system impedance characteristics and filter operating frequency) effectively avoids resonance and ensures stable operation of the filter and the entire system.

[0075] Step 6: Determine the DC link voltage level based on the rated parameters.

[0076] It's important to note that the DC-side voltage level refers to the operating voltage level on the DC side of the converter, which directly impacts the system's power transmission capacity and equipment selection. Determining the appropriate voltage level based on rated parameters (such as generator output characteristics, grid access requirements, and converter withstand voltage) ensures efficient system power transmission while ensuring equipment safety and cost-effectiveness.

[0077] Step 7: Determine the control systems of the wind turbine generator system's generator-side converter and grid-side converter.

[0078] It should be noted that the generator-side converter control system primarily controls the generator, such as implementing maximum power point tracking (MPPT) to maximize wind energy capture at varying wind speeds. The grid-side converter control system is responsible for converting DC power into AC power that meets grid requirements, including stabilizing the DC voltage and controlling the decoupled output of active and reactive power. Common control strategies include vector control and direct torque control. Selecting the appropriate control strategy and algorithm based on system requirements ensures precise converter control.

[0079] Step 8: Based on the DC side capacitance value, damping resistor value, DC side voltage level, and the AC side commutation inductance and filter capacitance values ​​of the converter determined within their respective value ranges, use simulation software to verify and optimize the control strategy of each parameter and control system.

[0080] It's important to note that simulation software can be used to build a mathematical model of a wind turbine system and simulate its operation under different operating conditions. By inputting the determined parameters and control strategies into the model, the system's output responses (such as voltage and current waveforms, power transmission efficiency, etc.) are observed to determine whether they meet design requirements. If not, the parameters or control strategies can be adjusted and optimized to reduce actual development costs and risks and improve design accuracy and reliability.

[0081] Step 9: Based on the optimized system parameters, the experimental system built on the hardware platform is used for re-verification. After verification, the final system parameters and control system design are obtained.

[0082] It should be noted that the hardware platform is a real-world wind power system experimental setup, including a wind turbine simulator, generator, converter, filter, transformer, and other equipment. Based on simulation optimization, hardware experiments further verify the performance and reliability of system parameters and control strategies in actual operation, and examine factors not accounted for in the simulation (such as electromagnetic interference and equipment losses). Only through hardware experimental verification can the final system parameters and control system design be determined, ensuring their feasibility and effectiveness in actual projects.

[0083] In one embodiment of the present invention, the design of the DC side capacitor parameters is similar to that of the photovoltaic power generation unit. In order to maintain a relatively constant DC voltage, a capacitor with a larger capacitance is usually used. At the same time, the capacitance parameter size is designed according to the energy required to be maintained. The calculation expression is:

[0084]

[0085] Where, is the DC side capacitance value; is the rated output power; To keep time; is the energy output efficiency; is the DC side voltage value.

[0086] The parameter design of the AC side of the converter includes the commutation inductor and filter capacitor, and needs to be considered from aspects such as current ripple amplitude, inductor voltage drop, filter capacitor reactive absorption, and resonant frequency.

[0087] In one embodiment of the present invention, the value range of the commutation inductance is determined according to the following process:

[0088] a) According to the SPWM modulation characteristics, the pulsating current expression at the carrier frequency is derived as follows:

[0089]

[0090] b) The lower limit of the commutation inductance is obtained as follows:

[0091]

[0092] c) In order to limit the voltage drop at the fundamental frequency, the following conditions must be met:

[0093]

[0094] d) The upper limit of the commutation inductance is as follows:

[0095]

[0096] Where, is the commutation inductor; is the per-unit value of the harmonic voltage amplitude at the carrier frequency; is the DC side voltage value; is the permissible AC current pulsation amplitude; is the AC current rating; is the allowable voltage drop; is the line voltage; is the angular frequency, is the switching frequency.

[0097] In one embodiment of the present invention, the value range of the filter capacitance is determined according to the following process:

[0098] a) In order to limit the filter from absorbing too much reactive power, it is necessary to set an upper limit on the capacitance value. The reactive power of the three-phase filter can be expressed as:

[0099]

[0100] in, is the ratio of the allowed reactive power absorption.

[0101] b) The upper limit of the capacitance value is obtained:

[0102]

[0103] c) At the same time, in order to avoid resonance, the resonant frequency must meet the following requirements:

[0104]

[0105] d) The capacitance range is obtained:

[0106]

[0107] Where, is the filter capacitor; is the switching frequency; is the commutation inductor; is the fundamental frequency.

[0108] In one embodiment of the present invention, the calculation expression of the damping resistance value is as follows:

[0109]

[0110] Where, is the damping resistance value; is the resonant angular frequency; is the commutation inductance value; is the filter capacitor.

[0111] In one embodiment of the present invention, in order to prevent overmodulation within the rated power range due to too low a DC voltage, a lower limit needs to be set for the DC voltage level. The calculation expression of the modulation ratio is as follows:

[0112]

[0113] It is generally believed that in the absence of third harmonic injection, the modulation ratio cannot exceed 1, and if third harmonic injection is present, it cannot exceed 1.15. At the same time, a margin of about 5% needs to be retained. Combining the above conditions, the calculation expression for the DC voltage level can be obtained as follows:

[0114]

[0115] Where, is the DC voltage value, is the effective value of the AC phase voltage, is the maximum modulation ratio.

[0116] In one embodiment of the present invention, the grid-side converter adopts adaptive reactive component decoupling control, which realizes decoupling control of active component and reactive component based on dq coordinate transformation, wherein the active component is used to stabilize the DC side voltage; the reactive component is used to control the AC side voltage amplitude or reactive power; when a fault occurs in the power grid, the reactive current reference value is dynamically adjusted according to the low voltage ride-through curve, and the active output is limited at the same time.

[0117] Corresponding to the above primary system, the secondary control system mainly includes four parts: grid-side converter steady-state operation control, fault ride-through operation control, generator-side converter steady-state operation control, and Chopper branch protection control. The overall structure of the control system is as follows: Figure 3 As shown below, we will explain them separately:

[0118] (1) Steady-state operation control of grid-side converter

[0119] In one embodiment of the present invention, the grid-side converter steady-state operation control adopts adaptive reactive component decoupling control, the active component is mainly used to stabilize the DC side voltage, and the reactive component is used to control the AC side voltage amplitude or reactive power. Generally, in order to achieve unity power factor operation, the reactive command value is set to 0. Specifically, Figure 4 As shown in the figure, it consists of five components: per-unit conversion, phase-locked loop and Park transform, voltage outer loop control, current inner loop control, and PWM trigger signal generation. The outer loop active component is set to the DC bus voltage, and the reactive component is set to the AC side voltage amplitude or reactive power as required.

[0120] (2) Grid-side converter fault ride-through control

[0121] When a fault occurs on the grid side, the voltage drop on the AC side will cause a decrease in power transmission capacity. Due to the large inertia of the mechanical part of the wind turbine, the wind power it captures cannot change quickly, resulting in power imbalance and causing the DC bus voltage to rise rapidly. Therefore, it is necessary to limit the active power output accordingly and provide reactive support voltage to the grid to maintain power transmission capacity and avoid the unit being disconnected from the grid due to excessively low voltage. In addition, for direct-drive wind turbine generator sets, since the back-to-back full-power converters naturally have isolation properties, the above adjustments can be limited to the grid-side converter, and the machine-side converter does not need to be adjusted. The grid-side converter fault ride-through control structure is as follows: Figure 5The logic is as follows: the operating condition is determined based on the low voltage ride-through curve. When the low voltage ride-through condition is met, the inner loop current reference value is no longer input from the outer loop. The reactive current reference value is calculated based on the voltage sag depth to provide sufficient reactive power support. The upper limit of the active current reference value is calculated based on the grid-side current limit and the reactive current to limit the active power output. The three satisfy the following relationship:

[0122]

[0123] Where, is the reactive current reference value, is the current limit value of the grid-side converter, is the active current reference value.

[0124] (3) Steady-state operation control of the generator-side converter

[0125] In one embodiment of the present invention, the generator side converter adopts maximum power point tracking control. The generator side converter steady state control is mainly used to achieve maximum power tracking of wind power, and also adopts per-unit double closed loop control. Its control structure is as follows: Figure 6 shown.

[0126] Under the premise that the reference direction of all measurement parameters follows the generator reference, for the voltage outer loop controller, when the generator adopts a salient pole machine and the dq axis inductance is inconsistent and cannot be ignored, in order to ensure decoupled control, the outer loop active component output idref needs to be set to 0. In other cases, the active component can be set to reactive power and controlled independently; the reactive component is set to the generator electromagnetic torque. By tracking the optimal torque calculated from the current speed and maximum power point, the maximum power tracking of the wind turbine output power is achieved. The calculation formula is as follows:

[0127]

[0128] Where, is the optimal electromagnetic torque, is the optimal torque coefficient, is the optimal rotor angular velocity.

[0129] (4) Chopper branch protection control

[0130] In one embodiment of the present invention, a chopper protection circuit is configured on the DC side of the wind turbine system. To prevent overvoltage on the DC bus capacitor during low voltage ride-through (LVRT), a chopper circuit is activated to dissipate excess power when the DC bus voltage exceeds a limit, limiting the rise in DC bus voltage.

[0131] Based on the above design, the station-level startup control of the wind power generation unit system of the present invention is mainly based on the startup process of each wind power generation unit. Figure 7 The large-scale wind farm shown and Figure 8 A single wind power generation unit is shown as an example for explanation.

[0132] When using grid-following control, it is first necessary to close the grid-connected switch at the outlet of each power generation unit to establish an effective AC side voltage. At the same time, when the converter control signal remains locked, the anti-parallel diode in the switch group will be used for uncontrolled rectification to charge the DC bus capacitor and initially establish a DC voltage. In some topologies, the DC side will also be pre-charged by connecting a switch + power supply to the DC side; first, the grid-side converter control signal is unlocked, and the DC voltage continues to rise to the set value and remains stable. At the same time, the permanent magnet synchronous generator adopts speed control to maintain stability; subsequently, the machine-side converter control signal is unlocked, and the generator's outlet switch is closed to connect it to the network. The permanent magnet synchronous generator switches to torque control to start outputting power. At the same time, the machine-side converter begins to adjust the torque for maximum power tracking, so that the system gradually reaches the maximum power point and enters a steady-state operation state.

[0133] Based on the above embodiments, it can be seen that the wind power generation unit system and the topology parameter optimization and control design method provided by the present invention have the following advantages:

[0134] 1. High efficiency: Reasonable parameter design and advanced control strategy reduce converter loss and improve system conversion efficiency.

[0135] 2. High stability: Precise DC bus voltage control enables the system to operate stably under both normal and fault conditions.

[0136] 3. High power quality: effectively suppresses harmonics and improves the output power quality.

[0137] 4. Strong adaptability: It can adapt to different wind conditions and grid operating conditions and has good grid adaptability.

[0138] 5. Strong fault ride-through capability: Adopting low voltage ride-through strategy, the grid can be kept stable even in the event of a grid fault.

[0139] 6. Excellent control performance: adopting control strategies such as MPPT, it can effectively track the maximum power point of the wind turbine.

[0140] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0141] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0142] In the embodiments disclosed in the present application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0143] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A wind power generation unit system topology parameter optimization and control design method, characterized in that: include: Determine the rated parameters of the wind power unit system; Calculating a DC side capacitance value of the converter based on the rated parameters; Determining a value range of the commutation inductance on the AC side of the converter based on the rated parameters; determining a value range of the filter capacitance based on the rated parameters; determining a damping resistance value of the filter based on the rated parameters; determining a DC side voltage level based on the rated parameters; Determine the control systems of the machine-side converter and grid-side converter of the wind power generation unit system; Based on the DC side capacitance value, the damping resistor value, the DC side voltage level, and the AC side commutation inductance value and filter capacitance value of the converter determined within their respective value ranges, using simulation software to verify and optimize the various parameters and the control strategy of the control system; Based on the optimized system parameters, the experimental system built on the hardware platform is used for re-verification. After the verification is passed, the final system parameters and control system design are obtained.

2. The wind power generation unit system topology parameter optimization and control design method according to claim 1, characterized in that: The calculation expression of the DC side capacitance value is as follows: Where, is the DC side capacitance value; is the rated output power; To keep time; is the energy output efficiency; is the DC side voltage value.

3. The wind power generation unit system topology parameter optimization and control design method according to claim 1, characterized in that: The value range of the commutation inductance is determined according to the following formula: Where, is the commutation inductor; is the per-unit value of the harmonic voltage amplitude at the carrier frequency; is the DC side voltage value; is the permissible AC current pulsation amplitude; is the AC current rating; is the allowable voltage drop; is the line voltage; is the angular frequency, is the switching frequency.

4. The wind power generation unit system topology parameter optimization and control design method according to claim 1, characterized in that: The value range of the filter capacitance is determined according to the following formula: Where, is the filter capacitor; is the switching frequency; is the commutation inductor; is the fundamental frequency.

5. The wind power generation unit system topology parameter optimization and control design method according to claim 1, characterized in that: The calculation expression of the damping resistance value is as follows: Where, is the damping resistance value; is the commutation inductance value; is the filter capacitor.

6. The wind power generation unit system topology parameter optimization and control design method according to claim 1, characterized in that: The DC side voltage level is determined according to the range of the DC side voltage value, and the range of the DC side voltage value is determined according to the following formula: Where, is the DC voltage value, is the effective value of the AC phase voltage, is the maximum modulation ratio.

7. The wind power generation unit system topology parameter optimization and control design method according to claim 1, characterized in that: The grid-side converter adopts adaptive reactive component decoupling control, which realizes decoupling control of active component and reactive component based on dq coordinate transformation, wherein the active component is used to stabilize the DC side voltage; the reactive component is used to control the AC side voltage amplitude or reactive power; when a fault occurs in the power grid, the reactive current reference value is dynamically adjusted according to the low voltage ride-through curve, and the active output is limited at the same time.

8. The wind power generation unit system topology parameter optimization and control design method according to claim 1, characterized in that: The generator-side converter adopts maximum power point tracking control.

9. The wind power generation unit system topology parameter optimization and control design method according to claim 1, characterized in that: The DC side of the wind power generation unit system is equipped with a Chopper protection circuit.

10. A wind power generation unit system, characterized in that: The system parameters and control system are determined based on the wind power generation unit system topology parameter optimization and control design method according to any one of claims 1 to 9, including: Wind turbines, permanent magnet synchronous generators, back-to-back full-power converters, filters and step-up transformers; The wind turbine is used to convert wind energy into mechanical energy; The permanent magnet synchronous generator is used to convert the mechanical energy into AC electrical energy; The back-to-back full-power converter is used to convert the AC power into AC power that matches the frequency, phase and amplitude of the power grid. The back-to-back full-power converter includes a machine-side converter and a grid-side converter, and both use a two-level voltage source converter; The filter is used to filter out harmonic components in the output current of the back-to-back full-power converter; The step-up transformer is used to step up the AC power output by the back-to-back full-power converter to the voltage level required by the power grid.

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