Simulation Design and Grid-Connected Operation Control Methods for Large-Scale Wind Power Hydrogen Production Systems

Abstract

This invention discloses a simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system. In this system, the wind turbines are connected to the power grid via converters. The power grid delivers electrical energy to the hydrogen production power source via transformers, and the hydrogen production power source supplies power to the electrolyzer via converters. The system consists of the wind turbine body, permanent magnet synchronous motor, turbine-side converter, grid-side converter, energy storage device, hydrogen production power source, and electrolyzer. The control strategy of the controller unit includes voltage-current dual closed-loop control and power-current dual closed-loop control. A dVOC oscillator control method is added to the grid-connected controller of the energy storage device, and a grid-controlled inverter is used to make the DC side exhibit voltage source characteristics, increasing voltage regulation and improving system stability after disturbances. This invention proposes a controlled current source equivalent method to replace the modeling of hundreds of wind turbines and electrolyzer units in a large-capacity system, reducing the workload of model building and improving simulation calculation speed.

Description

Technical Field

[0001] This invention belongs to the field of wind power hydrogen production operation control technology in the new energy sector, specifically involving a simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system. Background Technology

[0002] New energy power generation has replaced fossil fuel power generation based on synchronous generators. Due to the randomness and intermittency of wind energy, large-scale wind farms have a certain impact on the stability of the power system, leading to a decrease in the system's inertia and power frequency response capability. As the load in the system changes, it threatens the stability of the system frequency, and under the condition of large disturbances, the entire system may lose stability. In addition, the randomness and intermittency of new energy power generation will also increase the active power imbalance of the system, causing continuous frequency deviation. Therefore, this invention proposes to add an energy storage device to the grid-connected output side of the wind turbine and adopt a control method with synchronous generator characteristics to realize grid-connected control inverter. It abandons the current source characteristics caused by the original phase-locked loop tracking the phase angle of the grid point, and changes the control target to voltage amplitude and phase angle, so that the distributed power source output to the grid exhibits voltage source characteristics, with the characteristics of synchronous generators and the effects of maintaining grid power balance, stabilizing voltage, and regulating frequency. Summary of the Invention

[0003] To overcome the problems brought about by hydrogen production from new energy power generation, this invention provides a simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system. The simulation design and grid-connected operation control of the wind power hydrogen production system are realized through a dynamic model of the hydrogen production system, a power electronic circuit model, an energy storage device module, and a converter control module.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system is disclosed. The large-scale wind power hydrogen production system includes a wind turbine, a permanent magnet synchronous motor, an AC-DC-AC converter, a filter, a transformer, an electrolyzer, a hydrogen production power supply, an energy storage device, and a simulated large power grid. The wind turbine drives the permanent magnet synchronous motor to convert wind energy into alternating current (AC) for power generation. The AC-DC-AC converter converts the AC power into direct current (DC) and then back into AC power for grid connection. The electrical energy is transmitted to the hydrogen production power supply via the transformer. The AC power is then converted to DC power by the AC-DC converter to power the electrolyzer to produce hydrogen. The energy storage device is connected to the grid connection outlet side of the wind turbine and charged through the AC-DC converter.

[0006] Furthermore, the AC-DC converter on the wind turbine side is configured according to the wind speed of the wind turbine body. Fan speed The relationship between the fan blade radius r and the tip speed ratio λ is used to obtain the reference fan speed. It serves as a reference for the speed of the permanent magnet synchronous generator, forming the speed loop of the converter control strategy, and controlling the q-axis current after the AC side current undergoes Park transformation. Form a reference signal;

[0007] (1)

[0008] (2)

[0009] (3)

[0010] (4)

[0011] In the formula, This refers to the output power of the permanent magnet synchronous motor. The mechanical power captured by the wind turbine; Wind energy utilization coefficient; It is the blade pitch angle; it is the tip speed ratio; air density; Wind turbine radius; It's wind speed; , This refers to the dq-axis current components on the AC side. For motor magnetic flux, , Let dq-axis components be the inductance of the motor. Angular frequency, It's the gearbox ratio. It is the fan speed. It's wind speed;

[0012] The wind turbine grid-connected side adopts a dual closed-loop control strategy with an outer voltage loop and an inner current loop. On the grid-side portion of the wind turbine, the DC-side capacitor voltage is used. To control the outer ring, The desired voltage amplitude is used to form the outer voltage loop. The difference between the two values ​​corresponds to the d-axis current on the dq axis after Park transformation of the grid-connected AC power. To take control;

[0013] (5)

[0014] (6)

[0015] (7)

[0016] (8)

[0017] (9)

[0018] (10)

[0019] (11)

[0020] In the formula, , , This refers to the phase voltage on the grid side. , , This refers to the current on the grid side. , , It is the phase voltage of a three-phase grid-connected line; The d-axis component of the grid-side voltage; This refers to the q-axis component of the grid-side voltage. This refers to the d-axis component of the AC side voltage of the converter. This refers to the q-axis component of the AC side voltage of the converter. For filtering the AC side lines of the converter; Angular frequency; , These are the dq-axis current components on the AC side of the converter, respectively.

[0021] The electrolytic cell uses an AC-DC converter, and the voltage is obtained by converting the three-phase grid voltage through a Parker converter. , Using the relationship between dq-axis voltage and power, the d-axis current after the three-phase AC power undergoes Park transformation can be calculated. The reference signal uses single-loop current control and serves as the d-axis current. Reference signal, and control it;

[0022] (12)

[0023] (13)

[0024] The AC-DC converter of the energy storage device adopts a power outer loop and current inner loop control strategy. Used as a reference signal to control the converter output;

[0025] (14)

[0026] (15)

[0027] During the dq transformation, the d-axis is made to be in phase with the space vector of the grid voltage, so the q-axis component of the grid voltage is zero.

[0028] (16)

[0029] (17)

[0030] In the formula, P and Q represent the three-phase active and reactive power on the grid side; , These are the active and reactive current components on the grid side, respectively. The d-axis component of the grid-side voltage; This refers to the q-axis component of the grid-side voltage. , respectively on the power grid side shaft and Axis voltage components; , respectively on the power grid side shaft and Axis current components;

[0031] In the AC-DC converter control of energy storage devices, dVOC is added at the upper level, and the oscillator consists of two inputs. The difference between the shaft current and the reference circuit is amplified. As the input to the oscillator, the oscillator output is amplified by a certain factor. The signal is sent to the modulator to generate a PWM wave;

[0032] The virtual oscillator exhibits the following nonlinear relationship: (18)-(19) formulas are used to derive the nonlinear element within the virtual oscillator using a controlled voltage source. and controlled current source express:

[0033] (18)

[0034] (19)

[0035] (20)

[0036] in, This represents the reference value for the line-to-neutral point voltage; It is determined by the voltage across the capacitor in the internal circuit of the oscillator. and the amplified inductor current constitute;

[0037] The virtual oscillator contains an LC circuit and has a resonant frequency. The proportional parameter of the voltage source input The following is an example:

[0038] (twenty one)

[0039] (twenty two)

[0040] in, , These are the inductance and capacitance values ​​in the internal circuitry of the oscillator, respectively.

[0041] power grid The shaft reference current is obtained from the reference active power and the active power, and the formula is expressed as follows:

[0042] (twenty three)

[0043] in, , It is through the reference signal , Calculated Reference current on the shaft;

[0044] The output of the dVOC dynamic equation of the virtual oscillator, derived from (18)-(22), is as follows:

[0045] (twenty four)

[0046] (25)

[0047] (26)

[0048] in, This is the reference value for the output voltage from the mains line to the neutral point. , It is the output of the oscillator. The first derivative of the voltage on the axis;

[0049] Representing equations (24)-(26) in polar coordinates as follows, we obtain dVOC. , Relationships to achieve grid-controlled inverters:

[0050] (27)

[0051] (28)

[0052] In the formula, It is a design parameter that controls the convergence speed of the oscillator; , These are the output current and voltage of the controlled current source and voltage source of the oscillator. , This is to achieve the interface between the oscillator and the inverter power stage, and to scale the interfaces of the two oscillators; (symbol) It is the Euclidean norm; This refers to the limit radius of the oscillator's annular ring; , It includes active power reference and reactive power reference; It is the resonant frequency; , It is the output voltage of the oscillator. Axial components; , It is the AC side grid current. Quantity; It is the voltage of the virtual oscillator capacitor; It is the oscillator inductor current; , These are the transient active and reactive power outputs of the inverter; It is the dVOC control output voltage reference; It is the dVOC output phase angle reference; It is the first derivative of the dVOC output voltage vector; yes The first derivative is obtained.

[0053] Furthermore, in the simulation system, the large-scale wind power hydrogen production system adopts the method of collecting the grid-side current of a single wind turbine and using a controlled source equivalent grid connection method to model hundreds of wind turbine systems. The hundreds of wind turbine systems are equivalently represented by a large current injection method, which reduces the burden on the simulation system and improves the simulation calculation speed. The electrolyzers are large-capacity, including nearly a hundred units. In the simulation system design, the three-phase current of the AC side of one electrolyzer is collected, and the controlled current source equivalent method is used to model multiple electrolyzer models.

[0054] Furthermore, the electrolytic cell has a reverse voltage. and an internal resistor An equivalent electrolytic cell with a circuit structure that conforms to the characteristics of both is adopted, wherein the internal resistance, in It is related to stack quality. It is related to the gas concentration; It is a variable resistor; ,in and It is a constant coefficient, and A is the electrode area.

[0055] Furthermore, an L-shaped filter is used on the grid-connected outlet side of the wind turbine to facilitate grid-connected operation.

[0056] Furthermore, a phase-locked loop is used to ensure that the wind turbine is connected to the grid and the hydrogen production unit maintains phase synchronization with the power grid.

[0057] Furthermore, the hydrogen production power supply uses multiple rectifiers connected in parallel to simultaneously power the electrolyzer, improving system stability.

[0058] Beneficial Effects: Grid-connected operation of new energy sources is currently a very popular research direction. This invention configures energy storage devices at the grid connection outlet of distributed generation power sources and uses a grid-connected inverter control method based on a synchronous generator model for these energy storage devices. This allows the distributed power source to exhibit the characteristics of a synchronous generator to the grid, maintaining system power balance and voltage stability. Currently, the mainstream control methods for grid-connected inverters of energy storage devices include virtual synchronous machine control and droop control. This invention adopts the dVOC control method, which has better stability under large disturbances compared to virtual synchronous machine control and droop control. Furthermore, the grid-connected inverter control for energy storage devices achieves grid-connected inverter control, abandoning the use of phase-locked loops to track the grid connection point, resulting in better inherent stability. Attached Figure Description

[0059] Figure 1 This is a schematic diagram illustrating the overall design of the simulation design and grid-connected operation control method for the large-scale wind power hydrogen production system of the present invention.

[0060] Figure 2 This is a topology diagram for large-scale wind power hydrogen production.

[0061] Figure 3 This is a topology diagram of a single wind turbine control strategy.

[0062] Figure 4 Topology diagram for dVOC control of grid-connected inverter.

[0063] Figure 5 This is a graph showing the DC capacitor voltage curve on the grid-connected side of the wind turbine.

[0064] Figure 6 This is the load voltage curve of the hydrogen production unit in hydrogen production. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0066] like Figure 1As shown, the large-scale wind power hydrogen production system simulation design and grid-connected operation control method of this invention utilizes a large-scale wind power hydrogen production system comprising wind turbines, AC-DC-AC converters, AC-DC converters, power circuits, transformers, a large power grid, power electronic hydrogen production power supplies, and electrolyzers. This system is a GW-level wind power hydrogen production system, where hundreds of wind turbines generate electricity which is then fed into the power grid via converters. The electricity is then supplied to the hydrogen production power supply via step-up and step-down transformers, and the hydrogen production power supply is connected to the electrolyzers to produce hydrogen. In the wind turbine grid-connected section, the wind turbine itself drives a permanent magnet synchronous motor to convert wind energy into AC power, which is then stepped up by a transformer and connected to the large power grid. In the hydrogen production section, the AC power on the line is stepped down by a step-down transformer to the required voltage, and then supplied to the electrolyzers via an AC-DC converter to produce hydrogen.

[0067] like Figure 2 As shown, considering the large overall capacity of the design simulation, which may lead to slow simulation speed, an equivalent replacement for the wind turbines is proposed. For the three-phase line current measured at the grid connection outlet of one wind turbine, a controlled current source is used to equivalently replace the output of other wind turbines, connected to the grid connection side via a transformer. This significantly improves the efficiency and speed of the design simulation. Furthermore, configuring the energy storage device at the grid connection outlet of the wind farm is more economical than configuring it on the DC side. Simultaneously, employing appropriate control strategies for the energy storage battery inverter allows the wind farm to smoothly deliver power to the grid, reducing the wind farm's impact on grid frequency and exhibiting the external characteristics of a synchronous motor.

[0068] like Figure 3 The single wind turbine control strategy topology diagram shown employs a speed outer loop and current inner loop control method in the turbine-side converter. The power equation under the dq axis of its permanent magnet synchronous motor indicates that the electromagnetic power of the motor is related to the speed. Therefore, the speed outer loop references the output control of the q-axis current.

[0069] The large-scale wind power hydrogen production system converts the electrical energy supplied by the wind turbine into grid power, which is then sent to the hydrogen production power source through the large power grid and converted into DC power by the converter device to supply the electrolyzer model.

[0070] The energy storage device is used to store electrical energy on the grid-connected side of wind power generation. It has an internal converter control strategy that uses power control. It generates a reference signal based on the relationship between active power, three-phase current, and dq-axis voltage and current after the current is transformed by Park, forming a power control loop. After Park inverse transformation, the adjusted three-phase voltage and current are modulated to generate SPWM waves and sent to the controller. After receiving the adjustment information, the converter makes corresponding adjustments.

[0071] Preferably, the present invention includes an AC-DC converter and a DC-AC converter back-to-back, wherein the AC-DC-AC converter is a wind turbine grid-connected converter, including a turbine side and a grid side, and the AC-DC converter is an electrolyzer hydrogen production power converter and an energy storage device converter.

[0072] Preferably, the circuit model of the electrolytic cell includes a reverse voltage. Reverse voltage internal resistance ; including internal resistance ,in It is related to stack quality. It is related to the gas concentration. It is a variable resistor. ,in and It is a constant coefficient, and A is the electrode area.

[0073] like Figure 4 As shown, the virtual oscillator control method uses the reference active power... and no merit Through active and reactive power The relationship of the current on the shaft was calculated. Shaft reference current , With the actual power grid shaft current , The deviation is used as the input of the oscillator. After passing through the first-order nonlinear element of the oscillator, the output based on the relationship between active power and phase angle and reactive power and voltage under the first-order nonlinear oscillation is used as the reference voltage and reference phase angle. This makes its external characteristics exhibit voltage source characteristics, and it has the characteristics of a synchronous generator supporting the grid voltage and frequency.

[0074] Furthermore, a wind turbine grid-connected model is constructed, in which the wind turbine is a semi-direct drive unit that powers a permanent magnet synchronous motor. The output power relationship between the wind turbine and the permanent magnet synchronous motor is as follows.

[0075] (1)

[0076] (2)

[0077] (3)

[0078] The d-axis of the coordinate system is lagging behind the grid voltage vector by 90°, and its AC side active power... and reactive power The current on the dq axis after the three-phase alternating current passes through Park , and voltage on the dq axis and The voltage relationship is as follows:

[0079] (4)

[0080] (5)

[0081] In the formula, This refers to the output power of the permanent magnet synchronous motor. The mechanical power captured by the wind turbine; Wind energy utilization coefficient; It is the propeller pitch angle; It is the tip speed ratio; air density; Wind turbine radius; It's wind speed; , This refers to the dq-axis current components on the AC side. For motor magnetic flux, , Let dq-axis components be the inductance of the motor. For the motor output torque, This represents the number of pole pairs of the motor. ω is the angular frequency.

[0082] The wind turbine generator-side control principle involves controlling the permanent magnet generator speed by detecting the rotor position and reference flux linkage to achieve power control; the flux linkage reference... It should be set to 0; the permanent magnet synchronous generator speed signal is compared with the set speed, and then the current reference signal for outputting control torque is generated by the PI regulator. This constitutes the control strategy of the speed outer loop and the current inner loop.

[0083] Furthermore, on the grid side of the wind turbine, the main focus is on maintaining a stable DC bus voltage. Controlling the active power on the AC side essentially involves controlling the active component of the output current, and similarly, controlling the reactive component of the current is equivalent to controlling the reactive power output. Therefore, a dual closed-loop control strategy with an outer voltage loop and an inner current loop is adopted. On the grid side of the wind turbine, the DC side capacitor voltage is used as the control factor. To control the outer ring, The desired voltage amplitude is used to form the outer voltage loop. The difference between the two values ​​corresponds to the d-axis current on the dq axis after Park transformation of the grid-connected AC power. For control purposes, the three-phase voltage-current equations of the grid-connected inverter can be expressed as:

[0084] (6)

[0085] (7)

[0086] (8)

[0087] Meanwhile, the three-phase voltage and current on the wind turbine grid side are symmetrical in space and phase, so the following relationship is satisfied:

[0088] (9)

[0089] (10)

[0090] There is a coupling relationship between the dq-axis voltage component on the grid side and the dq-axis voltage component at the AC output of the converter:

[0091] (11)

[0092] (12)

[0093] In the formula, , , This refers to the phase voltage on the grid side. , , This refers to the current on the grid side. , , It is the phase voltage of a three-phase grid-connected line; The d-axis component of the grid-side voltage; This refers to the q-axis component of the grid-side voltage. This refers to the d-axis component of the AC side voltage of the converter. This refers to the q-axis component of the AC side voltage of the converter. For filtering the AC side lines of the converter; Angular frequency; , These are the dq-axis current components on the AC side of the converter, respectively.

[0094] Furthermore, the energy storage device optimizes its control strategy based on the voltage outer loop and current inner loop, adding a dVOC (schedulable virtual oscillator control) strategy on top of the original control method. The oscillator is excited by two inputs to generate nonlinear dynamics and steady-state droop response oscillations, and the active power at the controlled point is... and angular frequency Obtained through processing No merit and voltage The electromotive force reference is obtained from the relationship, and there is no need to track the grid phase. The phase of the dq transformation is obtained by controlling the output phase angle of dVOC. The overall output characteristics of the energy storage device are a voltage source and a phase angle, which makes the converter output have synchronous machine characteristics to provide voltage and frequency support to the grid. Shaft reference current , Obtained through the relationship of instantaneous power theory, and then through the amplification factor. It serves as the interface between the oscillator and the inverter power stage; the oscillator output is amplified by a certain factor. The signal is sent to the modulator to generate a PWM wave. It should be noted that dVOC control does not require the measurement and calculation of active power.

[0095] The following is the nonlinear circuitry within the virtual oscillator, determined by voltage and current sources, as follows:

[0096] (13)

[0097] (14)

[0098] (15)

[0099] in, This indicates the reference value of the voltage from the neutral line to the grid. It is determined by the voltage across the capacitor in the internal circuit of the oscillator. and the amplified inductor current constitute.

[0100] The virtual oscillator contains an LC resonant frequency and a scaling parameter. :

[0101] (16)

[0102] (17)

[0103] In the formula, , The inductance and capacitance values ​​are respectively those of the internal circuitry of the oscillator. Using formula (18), the reference current can be obtained by referring to the relationship between active power, reactive power, and oscillator output voltage:

[0104] (18)

[0105] in, , It is through the reference signal , Calculated Reference current on the shaft.

[0106] The dynamic equations for dVOC control based on equations (13)-(18) are expressed as follows:

[0107] (19)

[0108] (20)

[0109] (twenty one)

[0110] in This is a reference value for the output voltage from the mains line to the neutral point. , It is the output of the oscillator. The first derivative of the voltage on the axis.

[0111] Utilizing the amplitude and phase of transient voltage , The relationship is transformed into polar coordinates to obtain a nonlinear differential equation as follows. It can be seen from the following equation that the oscillator outputs voltage and phase angle. Its control method is added to the AC-DC converter control of the energy storage device. The phase angle output by the oscillator is used as the phase when the AC side of the energy storage device performs dq transformation. In this way, the energy storage device abandons the phase-locked loop to track the grid phase and realizes the grid-controlled inverter.

[0112] (twenty two)

[0113] (twenty three)

[0114] This shows , The relationship in dVOC control is nonlinear and dynamic.

[0115] In the formula, It is a design parameter that controls the convergence speed of the oscillator; , These are the output current and voltage of the controlled current source and voltage source of the oscillator. , This is to achieve the interface between the oscillator and the inverter power stage, by scaling the interfaces of the two oscillators; It is the Euclidean norm; This refers to the limit radius of the oscillator's toroidal ring. , It includes active power reference and reactive power reference; It is the resonant frequency; , It is the AC side grid voltage. Quantity; , It is the AC side grid current. Quantity; It is the voltage of the virtual oscillator capacitor; It is the oscillator inductor current; , These are the active and reactive power output by the inverter; It is the dVOC control output voltage reference; It is the dVOC output phase reference. It is the first derivative of the dVOC output voltage vector; yes The first derivative is obtained.

[0116] Its key advantage is that, in weak power grids, active power droop control may disrupt the transient stability of the system after being disturbed. dVOC can have a voltage regulation effect within a certain range, so it has a very small impact on the voltage in terms of the transient stability of the system.

[0117] Furthermore, a power outer loop and current inner loop control strategy is adopted in the hydrogen production power converter. The grid is connected to the converter to supply AC-DC power to the electrolyzer, thereby producing hydrogen. The relationship between its grid-side power and dq-axis voltage and current is as follows:

[0118] (twenty four)

[0119] (25)

[0120] In the formula, , This refers to the three-phase active and reactive power on the power grid side. , These are the active and reactive current components on the grid side, respectively. The d-axis component of the grid-side voltage; This refers to the q-axis component of the grid-side voltage.

[0121] at this time and These represent the active and reactive current components on the grid side, respectively. and The control is actually the control of the active and reactive power of the power grid.

[0122] This invention designs a simulation method for large-scale wind power-to-hydrogen production, simplifying the design model by using a controlled current source equivalent. Different control strategies are employed on the wind turbine grid-connected side: dual-loop control with an outer speed loop and an inner current loop, and dual-loop control with an outer voltage loop and an inner current loop, respectively. An energy storage device is added to the wind turbine grid-connected outlet side, employing a power outer loop and an inner current loop control strategy, along with an additional virtual oscillator control method. The energy storage device and the wind turbine form a synchronous machine characteristic, which is beneficial for smoothing the wind turbine output power and stabilizing the system frequency in large-scale wind power-to-hydrogen production. The electrolyzer unit is equivalent to a reverse voltage and internal resistance. Similarly, the inverter connected to the motor slot employs a single-loop current control strategy, ensuring that the active power effectively tracks the id current and guarantees DC-side voltage stability.

[0123] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system, characterized in that: The large-scale wind power hydrogen production system includes a wind turbine, a permanent magnet synchronous motor, an AC-DC-AC converter, a filter, a transformer, an electrolyzer, a hydrogen production power supply, an energy storage device, and a simulated large power grid. The wind turbine drives the permanent magnet synchronous motor to convert wind energy into alternating current (AC) for power generation. The AC-DC-AC converter converts the AC power into direct current (DC) and then back into AC power for grid connection. The electrical energy is transmitted to the hydrogen production power supply via the transformer. The AC power then passes through the AC-DC converter and uses DC power to supply the electrolyzer to produce hydrogen. The energy storage device is connected to the grid connection outlet side of the wind turbine and is charged through the AC-DC converter. In the AC-DC converter control of energy storage devices, dVOC is added at the upper level, and the oscillator consists of two inputs. The difference between the shaft current and the reference circuit is amplified. As the input to the oscillator, the oscillator output is amplified by a certain factor. The signal is sent to the modulator to generate a PWM wave; The virtual oscillator exhibits the following nonlinear relationship: (18)-(19) formulas are used to derive the nonlinear element within the virtual oscillator using a controlled voltage source. and controlled current source express: （18） （19） （20） in, This represents the reference value for the line-to-neutral point voltage; It is determined by the voltage across the capacitor in the internal circuit of the oscillator. and the amplified inductor current constitute; The virtual oscillator contains an LC circuit and has a resonant frequency. The proportional parameter of the voltage source input The following is an example: （21） （22） in, , These are the inductance and capacitance values ​​in the internal circuitry of the oscillator, respectively. power grid The shaft reference current is obtained from the reference active power and the active power, and the formula is expressed as follows: （23） in, , It is through the reference signal , Calculated Reference current on the shaft; The output of the dVOC dynamic equation of the virtual oscillator, derived from (18)-(22), is as follows: （24） （25） （26） in, This is a reference value for the output voltage from the mains line to the neutral point. , It is the output of the oscillator. The first derivative of the voltage on the axis; Representing equations (24)-(26) in polar coordinates as follows, we obtain dVOC. , Relationships to achieve grid-controlled inverters: （27） （28） In the formula, It is a design parameter that controls the convergence speed of the oscillator; , These are the output current and voltage of the controlled current source and voltage source of the oscillator. , This is to achieve the interface between the oscillator and the inverter power stage, and to scale the interfaces of the two oscillators; (symbol) It is the Euclidean norm; This refers to the limit radius of the oscillator's annular ring; , It includes active power reference and reactive power reference; It is the resonant frequency; , It is the output voltage of the oscillator. Axial components; , It is the AC side grid current. Quantity; It is the voltage of the virtual oscillator capacitor; It is the oscillator inductor current; , These are the transient active and reactive power outputs of the inverter; It is the dVOC control output voltage reference; It is the dVOC output phase angle reference; It is the first derivative of the dVOC output voltage vector; yes The first derivative is obtained.

2. The simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system according to claim 1, characterized in that: The AC-DC converter on the wind turbine side is based on the wind speed of the wind turbine body. Fan speed The relationship between the fan blade radius r and the tip speed ratio λ is used to obtain the reference fan speed. It serves as a reference for the speed of the permanent magnet synchronous generator, forming the speed loop of the converter control strategy, and controlling the q-axis current after the AC side current undergoes Park transformation. Form a reference signal; （1） （2） （3） （4） In the formula, This refers to the output power of the permanent magnet synchronous motor. The mechanical power captured by the wind turbine; Wind energy utilization coefficient; It is the blade pitch angle; it is the tip speed ratio; air density; Wind turbine radius; It's wind speed; , This refers to the dq-axis current components on the AC side. For motor magnetic flux, , Let dq-axis components be the inductance of the motor. Angular frequency, It's the gearbox ratio. It is the fan speed. It's wind speed; The wind turbine grid-connected side adopts a dual closed-loop control strategy with an outer voltage loop and an inner current loop. On the grid-side portion of the wind turbine, the DC-side capacitor voltage is used. To control the outer ring, The desired voltage amplitude is used to form the outer voltage loop. The difference between the two values ​​corresponds to the d-axis current on the dq axis after Park transformation of the grid-connected AC power. To take control; （5） （6） （7） （8） （9） （10） （11） In the formula, , , This refers to the phase voltage on the grid side. , , This refers to the current on the grid side. , , It is the phase voltage of a three-phase grid-connected line; The d-axis component of the grid-side voltage; This refers to the q-axis component of the grid-side voltage. This refers to the d-axis component of the AC side voltage of the converter. This refers to the q-axis component of the AC side voltage of the converter. For filtering the AC side lines of the converter; Angular frequency; , These are the dq-axis current components on the AC side of the converter, respectively. The electrolytic cell uses an AC-DC converter, and the voltage is obtained by converting the three-phase grid voltage through a Parker converter. , Using the relationship between dq-axis voltage and power, the d-axis current after the three-phase AC power undergoes Park transformation can be calculated. The reference signal uses single-loop current control and serves as the d-axis current. Reference signal, and control it; （12） （13） The AC-DC converter of the energy storage device adopts a power outer loop and current inner loop control strategy. Used as a reference signal to control the converter output; （14） （15） During the dq transformation, the d-axis is made to be in phase with the spatial vector of the grid voltage, so the q-axis component of the grid voltage is zero. （16） （17） In the formula, P and Q represent the three-phase active and reactive power on the grid side; , These are the active and reactive current components on the grid side, respectively. The d-axis component of the grid-side voltage; This refers to the q-axis component of the grid-side voltage. , respectively grid side shaft and Axis voltage components; , respectively grid side shaft and Axial current component.

3. The simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system according to claim 2, characterized in that: The large-scale wind power hydrogen production system in the simulation system adopts the method of collecting the grid-side current of a single wind turbine and using a controlled source equivalent grid connection method to model hundreds of wind turbine systems. The hundreds of wind turbine systems are equivalently represented by a large current injection method, which reduces the burden on the simulation system and improves the simulation calculation speed. The electrolyzers are large-capacity, including nearly a hundred units. In the simulation system design, the three-phase AC current of one electrolyzer is collected, and the controlled current source equivalent method is used to model multiple electrolyzer models.

4. The simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system according to claim 3, characterized in that: The electrolytic cell has a reverse voltage. and an internal resistor An equivalent electrolytic cell with a circuit structure that conforms to the characteristics of both is adopted, wherein the internal resistance, in It is related to stack quality. It is related to the gas concentration; It is a variable resistor; ,in and It is a constant coefficient, and A is the electrode area.

5. The simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system according to claim 4, characterized in that: An L-shaped filter is used on the grid-connected outlet side of the wind turbine to facilitate grid-connected operation.

6. The simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system according to claim 5, characterized in that: A phase-locked loop is used to ensure that the wind turbine is connected to the grid and the hydrogen production unit is kept in phase synchronization with the grid.

7. The simulation design and grid-connected operation control method for a large-scale wind power hydrogen production system according to claim 6, characterized in that: The hydrogen production power supply uses multiple rectifiers connected in parallel to simultaneously power the electrolyzer, improving system stability.

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