A control method and device of an energy storage converter and the energy storage converter

Abstract

This application discloses a control method, device, and energy storage converter for an energy storage converter. The method includes: determining the real-time grid frequency, real-time active power, and real-time reactive power based on the three-phase voltage and three-phase current on the AC side of the energy storage converter; determining a reference active power compensation amount based on the real-time grid frequency; correcting the reference active power compensation amount based on the battery state of charge on the DC side to obtain the actual active power compensation amount; determining the rotor phase angle of a virtual synchronous generator based on the actual active power compensation amount, real-time active power, real-time reactive power, and a preset target reactive power; determining the on / off state of each switch in the energy storage converter based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator; and generating a pulse width modulation signal based on the on / off state to control the on / off state of each switch in the energy storage converter. This method enables the energy storage converter to maintain efficient, stable, and safe operation under different battery state of charge conditions.

Description

Technical Field

[0001] This application relates to the field of energy storage converter technology, and in particular to a control method, device and energy storage converter for an energy storage converter. Background Technology

[0002] As the interface device between the battery energy storage system and the AC grid, the energy storage converter is a core component for achieving bidirectional power conversion. The virtual synchronous generator (VSG) control strategy, by simulating the inertia and damping characteristics of a synchronous generator, enables the energy storage converter to support grid frequency, and is one of the mainstream control methods for current energy storage converters. However, existing VSG control strategies do not fully consider the constraints of the battery's state of charge (SOC) on the actual regulation capability of the energy storage converter when determining the active power compensation amount. This leads to the continued output of power commands according to rated demand when the battery SOC deviates from the intermediate value, easily causing battery overcharging or over-discharging. Summary of the Invention

[0003] This application provides a control method, device, and energy storage converter for an energy storage converter, in order to solve the technical problem that existing virtual synchronous generator control strategies are prone to causing battery overcharging or over-discharging.

[0004] To address the aforementioned technical problems, in a first aspect, this application provides a control method for an energy storage converter. The method includes: determining the real-time grid frequency, real-time active power, and real-time reactive power of the AC side based on the three-phase voltage and three-phase current of the AC side of the energy storage converter; determining a reference active power compensation amount for the AC side based on the real-time grid frequency, wherein the reference active power compensation amount characterizes the active power compensation amount corresponding to the degree of deviation of the real-time grid frequency from the rated grid frequency; and adjusting the reference active power compensation amount based on the battery state of charge of the DC side of the energy storage converter. The process involves making corrections to obtain the actual active power compensation amount; determining the rotor phase angle of the virtual synchronous generator based on the actual active power compensation amount, the real-time active power, the real-time reactive power, and the preset target reactive power; determining the on / off state of each switch in the energy storage converter based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator, wherein the voltage amplitude reference value is determined based on the real-time reactive power and the preset target reactive power; generating pulse width modulation signals based on the on / off states, and controlling the on / off state of each switch in the energy storage converter through the pulse width modulation signals.

[0005] In the aforementioned control method for the energy storage converter, the deviation of the real-time grid frequency from the rated grid frequency is quantified into a reference active power compensation amount. This reference active power compensation amount is then corrected based on the battery state of charge on the DC side of the energy storage converter to obtain the actual active power compensation amount. This allows the energy storage converter to adaptively adjust the actual power output amplitude according to the current battery state of charge when responding to grid frequency regulation demands, preventing overcharging or over-discharging caused by the battery continuing to execute the same power command as the rated operating condition when the battery's state of charge is close to the upper or lower limit. Based on this, the rotor phase angle of the virtual synchronous generator is determined according to the actual active power compensation amount, real-time active power, real-time reactive power, and preset target reactive power. This gives the energy storage converter inertial and damping characteristics during power regulation, achieving smooth adjustment during frequency response and suppressing power oscillations. Simultaneously, the on / off state of each switch is directly determined based on the rotor phase angle and the voltage amplitude reference value determined by the real-time reactive power and the preset target reactive power, and pulse width modulation signals are generated accordingly to control the on / off state of each switch. The entire control link forms a complete closed loop from grid frequency detection to switch on / off control. While supporting grid frequency, it also takes into account battery life protection, system stability improvement and control delay reduction, enabling the energy storage converter to maintain efficient, stable and safe operation under different battery charge conditions.

[0006] In some embodiments, determining the reference active power compensation amount on the AC side based on the real-time grid frequency includes: determining a frequency deviation amount based on the real-time grid frequency, wherein the frequency deviation amount is equal to the difference between a preset reference grid frequency and the real-time grid frequency; and determining the reference active power compensation amount on the AC side based on the frequency deviation amount and a frequency regulation droop coefficient, wherein the reference active power compensation amount is equal to the product of the frequency deviation amount and the frequency regulation droop coefficient, and the frequency regulation droop coefficient is determined based on the rated active power of the energy storage converter and a preset frequency regulation response range.

[0007] In this embodiment, the difference between a preset reference grid frequency and the real-time grid frequency is defined as the frequency deviation. This frequency deviation is then multiplied by the frequency regulation droop coefficient to obtain the reference active power compensation, establishing a linear mapping relationship between the degree of grid frequency deviation and the active power compensation. This multiplicative relationship creates a fixed correspondence between the direction of frequency deviation and the direction of power compensation. Specifically, when the real-time grid frequency is lower than the preset reference grid frequency, the reference active power compensation is positive, indicating that the energy storage converter injects active power into the grid; when the real-time grid frequency is higher than the preset reference grid frequency, the reference active power compensation is negative, indicating that the energy storage converter absorbs active power from the grid. This calculation method is simple and clear, easy to implement in engineering, and provides an accurate basis for subsequent state-of-charge correction and virtual synchronous generator control.

[0008] In some embodiments, before determining the reference active power compensation amount on the AC side based on the frequency deviation and the frequency droop coefficient, the process includes: determining the rated active power, starting frequency, and ending frequency of the energy storage converter, wherein the starting frequency is the frequency at which the energy storage converter begins to respond to frequency regulation, and the ending frequency is the frequency at which the energy storage converter reaches its rated active power output; calculating the frequency difference based on the starting frequency and the ending frequency, wherein the frequency difference is equal to the absolute value of the difference between the ending frequency and the starting frequency; and determining the frequency droop coefficient based on the rated active power and the frequency difference, wherein the frequency droop coefficient is equal to the ratio of the rated active power to the frequency difference.

[0009] In this embodiment, by determining the rated active power, starting frequency, and ending frequency of the energy storage converter, the absolute value of the difference between the ending frequency and the starting frequency is taken as the frequency difference. The rated active power is then divided by this frequency difference to obtain the frequency regulation droop coefficient, thus clarifying the standardized tuning method for the frequency regulation droop coefficient. Since the frequency difference is calculated using an absolute value, the frequency regulation droop coefficient remains the same positive value regardless of whether the energy storage converter operates on a side where the real-time grid frequency is lower or higher than the rated grid frequency. This ensures that the energy storage converter has symmetrical frequency regulation response characteristics under both frequency rise and fall conditions. This tuning method determines the droop coefficient based on the rated active power of the energy storage converter and the frequency regulation response frequency range specified in the grid connection standard, ensuring that the frequency regulation response characteristics of the energy storage converter meet the grid connection technical requirements. Simultaneously, the ratio of rated active power to frequency difference visually reflects the frequency regulation capability of the energy storage converter.

[0010] In some embodiments, the step of correcting the reference active power compensation amount based on the battery state of charge on the DC side of the energy storage converter to obtain the actual active power compensation amount includes: determining a state of charge (SCC) constraint factor based on the battery SCC, wherein the SCC constraint factor is used to characterize the degree of deviation of the battery SCC from the target SCC; and determining the actual active power compensation amount based on the SCC constraint factor and the reference active power compensation amount, wherein the actual active power compensation amount is equal to the product of the SCC constraint factor and the reference active power compensation amount.

[0011] In this embodiment, by determining the state of charge (SOC) constraint factor based on the battery's SOC, and multiplying the baseline active power compensation by this SOC constraint factor to obtain the actual active power compensation, adaptive correction of the baseline active power compensation is achieved. The SOC constraint factor characterizes the degree of deviation of the battery's SOC from the target SOC. The further the battery's SOC deviates from the target SOC, the smaller the value of this factor, and the actual active power compensation decreases accordingly, automatically reducing the actual power output of the energy storage converter. When the battery's SOC approaches the target SOC, this factor approaches its maximum value, and the energy storage converter responds to frequency regulation requirements with near-full power output. This correction method actively prevents battery overcharging or over-discharging while responding to grid frequency regulation requirements, achieving coordinated optimization of frequency support and battery protection.

[0012] In some embodiments, determining the rotor phase angle of the virtual synchronous generator based on the actual active power compensation, the real-time active power, the real-time reactive power, and the preset target reactive power includes: determining the active power deviation and the reactive power deviation, wherein the active power deviation is equal to the difference between the actual active power compensation and the real-time active power, and the reactive power deviation is equal to the difference between the preset target reactive power and the real-time reactive power; determining the equivalent mechanical power drive based on the active power deviation and the reactive power feedback adjustment, wherein the equivalent mechanical power drive is equal to the sum of the active power deviation and the reactive power feedback adjustment, and the reactive power feedback adjustment is equal to the product of the reactive power deviation and the preset reactive power feedback coefficient; determining the rate of change of the virtual rotor angular frequency based on the equivalent mechanical power drive and the real-time grid angular frequency on the AC side; and determining the rotor phase angle of the virtual synchronous generator based on the rate of change of the virtual rotor angular frequency and the control cycle duration, wherein the control cycle duration is determined based on the timer interrupt cycle of the energy storage converter.

[0013] In this embodiment, by separately determining the active power deviation and reactive power deviation, the sum of the active power deviation and the reactive power feedback adjustment is used as the equivalent mechanical power drive. Based on this equivalent mechanical power drive and the real-time grid angular frequency, the rate of change of the virtual rotor angular frequency is determined. Then, based on this rate of change and the control cycle duration, the rotor phase angle is determined, thus achieving a complete solution to the virtual synchronous generator rotor motion equation. The reactive power feedback adjustment is obtained by multiplying the reactive power deviation by a preset reactive power feedback coefficient, coupling the reactive power deviation to the active power rotor motion equation. This ensures that the output active power is unaffected by voltage changes, enhancing the system's anti-interference capability. This method enables the energy storage converter to possess the inertia and damping characteristics of a synchronous generator during frequency response, achieving smooth power regulation and effectively suppressing power oscillations.

[0014] In some embodiments, before determining the on / off state of each switch in the energy storage converter based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator, the method further includes: determining a proportional adjustment amount and a current integral increment based on the reactive power deviation, wherein the proportional adjustment amount is equal to the product of the reactive power deviation and a preset proportional gain coefficient, and the current integral increment is equal to the product of the reactive power deviation and a preset integral gain coefficient; determining a current voltage adjustment amount based on the proportional adjustment amount and the current integral accumulation, wherein the current voltage adjustment amount is equal to the sum of the proportional adjustment amount and the current integral accumulation, and the current integral accumulation is determined based on the current integral increment; and determining a voltage amplitude reference value of the virtual synchronous generator based on the current voltage adjustment amount and a preset rated voltage amplitude, wherein the voltage amplitude reference value is equal to the sum of the current voltage adjustment amount and the rated voltage amplitude.

[0015] In this embodiment, the proportional control amount and the current integral increment are obtained by multiplying the reactive power deviation by a preset proportional gain coefficient and a preset integral gain coefficient, respectively. The proportional control amount is added to the current integral accumulation amount to obtain the current voltage control amount. This current voltage control amount is then superimposed on a preset rated voltage amplitude to obtain the voltage amplitude reference value, thus realizing the proportional-integral control conversion from reactive power deviation to voltage amplitude command. The proportional control amount is generated in real time based on the reactive power deviation amount of the current cycle to ensure the response speed of voltage regulation. The current integral increment is accumulated to the integral accumulation amount of the previous cycle to form the current integral accumulation amount, which is used to eliminate steady-state reactive power error. The proportional control amount and the current integral accumulation amount work together to ensure that the voltage amplitude at the grid connection point is controlled within the target range. By executing in parallel with the determination of the rotor phase angle, the amplitude and phase of the output voltage are controlled respectively, forming a complete virtual synchronous generator voltage regulation link.

[0016] In some embodiments, determining the on / off state of each switch in the energy storage converter based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator includes: determining the A-phase modulation wave phase, B-phase modulation wave phase, and C-phase modulation wave phase based on the rotor phase angle, wherein the A-phase modulation wave phase, B-phase modulation wave phase, and C-phase modulation wave phase differ from each other by 120 electrical degrees; and determining the on / off state of each switch based on the voltage amplitude reference value, A-phase modulation wave phase, B-phase modulation wave phase, and C-phase modulation wave phase. Define the current instantaneous values ​​of the A-phase modulation wave, B-phase modulation wave, and C-phase modulation wave; based on the current instantaneous values ​​of the A-phase modulation wave, B-phase modulation wave, C-phase modulation wave, and carrier signal, determine the on / off states of the A-phase upper bridge switch, B-phase upper bridge switch, and C-phase upper bridge switch, respectively; based on the on / off states of the A-phase upper bridge switch, B-phase upper bridge switch, and C-phase upper bridge switch, determine the on / off states of the A-phase lower bridge switch, B-phase lower bridge switch, and C-phase lower bridge switch, respectively.

[0017] In this embodiment, the phases of the modulation waves of phases A, B, and C, which are sequentially 120 electrical degrees apart, are determined based on the rotor phase angle. The current instantaneous values ​​of the three-phase modulation waves are determined based on the voltage amplitude reference value and the phases of each phase modulation wave. Then, the on / off states of the upper bridge switches of phases A, B, and C are determined based on the current instantaneous values ​​of the three-phase modulation waves and the current instantaneous value of the carrier signal. Furthermore, the on / off states of the lower bridge switches are determined based on the on / off states of the upper bridge switches. This establishes a complete mapping link from the rotor phase angle and voltage amplitude reference value of the virtual synchronous generator to the on / off states of the six switches in the three-phase inverter. The sequential 120-degree electrical degree phase difference between each phase modulation wave ensures the symmetry of the three-phase output voltage, and the introduction of the carrier signal enables a natural conversion from voltage amplitude commands to pulse width modulation.

[0018] In some embodiments, determining the on / off state of the A-phase bridge switch, B-phase bridge switch, and C-phase bridge switch based on the current instantaneous value of the A-phase modulation wave, the current instantaneous value of the B-phase modulation wave, the current instantaneous value of the C-phase modulation wave, and the current instantaneous value of the carrier signal includes: if the current instantaneous value of the A-phase modulation wave is greater than the current instantaneous value of the carrier signal, then the A-phase bridge switch is determined to be on; otherwise, the A-phase bridge switch is determined to be off. If the current instantaneous value of the B-phase modulation wave is greater than the current instantaneous value of the carrier signal, then the B-phase bridge switch is determined to be on; otherwise, the B-phase bridge switch is determined to be off. If the current instantaneous value of the C-phase modulation wave is greater than the current instantaneous value of the carrier signal, then the C-phase bridge switch is determined to be on; otherwise, the C-phase bridge switch is determined to be off.

[0019] In this embodiment, the current instantaneous values ​​of the A-phase modulation wave, B-phase modulation wave, and C-phase modulation wave are successively compared with the current instantaneous value of the carrier signal. Based on the comparison results, the on / off state of the A-phase, B-phase, and C-phase upper-bridge switches is determined, thus establishing a specific rule for determining the on / off state of the upper-bridge switches. This rule is directly executed by the controller hardware comparator: when the current instantaneous value of the modulation wave is greater than the current instantaneous value of the carrier signal, the corresponding phase upper-bridge switch is turned on; otherwise, it is turned off. This method eliminates the need for intermediate calculations of the duty cycle, mapping the change in the voltage amplitude reference value to the on / off time ratio of each phase upper-bridge switch in real time. This achieves instantaneous conversion from voltage command to switch control signal, reducing control delay and software complexity.

[0020] Secondly, this application provides a control device for an energy storage converter, the device comprising: The first determining module is used to determine the real-time grid frequency, real-time active power, and real-time reactive power of the AC side based on the three-phase voltage and three-phase current of the AC side of the energy storage converter; the second determining module is used to determine the reference active power compensation amount of the AC side based on the real-time grid frequency, wherein the reference active power compensation amount is used to characterize the active power compensation amount corresponding to the degree of deviation of the real-time grid frequency from the rated grid frequency; the correction module is used to correct the reference active power compensation amount based on the battery state of charge of the DC side of the energy storage converter to obtain the actual active power compensation amount; the third determining module is used to determine the reference active power compensation amount based on the battery state of charge of the DC side of the energy storage converter. The first module is used to determine the rotor phase angle of the virtual synchronous generator based on the actual active power compensation, the real-time active power, the real-time reactive power, and the preset target reactive power; the second module is used to determine the on / off state of each switch in the energy storage converter based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator, wherein the voltage amplitude reference value is determined based on the real-time reactive power and the preset target reactive power; the third module is used to generate a pulse width modulation signal based on the on / off state, and control the on / off state of each switch in the energy storage converter through the pulse width modulation signal.

[0021] Thirdly, this application provides an energy storage converter, characterized in that it includes a processor and a memory, the memory being used to store a computer program, which, when executed by the processor, implements the control method of the energy storage converter as described above. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart illustrating the control method of an energy storage converter according to an embodiment of this application; Figure 2 This is a schematic diagram of the control device for an energy storage converter shown in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of an energy storage converter shown in an embodiment of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a control method for an energy storage converter provided in an embodiment of this application. Figure 1 As shown, the control method of the energy storage converter in this embodiment includes steps S11 to S16, which are detailed below: Step S11: Determine the real-time grid frequency, real-time active power, and real-time reactive power of the AC side based on the three-phase voltage and three-phase current of the energy storage converter.

[0025] In this step, a voltage transformer and a current transformer are installed at the AC side grid connection point of the energy storage converter. The secondary side of the voltage transformer outputs a three-phase voltage analog signal. , , The secondary side of the current transformer outputs a three-phase current analog signal. , , The analog signal, after being filtered and amplitude-converted by the signal conditioning circuit, is input to the analog-to-digital converter (ADC) sampling channel of the energy storage converter controller. The controller triggers the ADC to perform synchronous sampling at a preset sampling frequency to obtain the instantaneous values ​​of the three-phase voltage. , , and instantaneous value of three-phase current , , .

[0026] Based on the above sampled values, the real-time power grid frequency f is determined in the following way: the instantaneous values ​​of the three-phase voltages are... , , After Clark transformation to the stationary coordinate system, we obtain , Then , After transforming to a rotating coordinate system using the Park transformation, we obtain... , The q-axis voltage is controlled via a digital phase-locked loop. The PI controller performs closed-loop regulation according to... The value adjusts the input phase of the Park transform in real time. until The angle approaches zero, at which point the phase-locked loop outputs an angle. This refers to the phase of the grid voltage. When When this time, it indicates that the phase-locked loop has locked the grid phase, and the output at this time is... This refers to the real-time phase of the grid voltage. The d-axis component... This process characterizes the real-time amplitude of the grid voltage. The real-time angular frequency of the power grid is obtained by differentiation. Then calculate the real-time power grid frequency. The proportional-integral parameters of the phase-locked loop are pre-tuned according to the power grid frequency fluctuation range and system response speed requirements.

[0027] Real-time active power P and real-time reactive power Q are determined as follows: In the stationary coordinate system, real-time active power P... Instantaneous reactive power To avoid the impact of pulsating components in instantaneous power on control accuracy, the real-time active power P and real-time reactive power Q are filtered by a low-pass filter to obtain smoothed real-time active power P and real-time reactive power Q. The instantaneous values ​​of the two-phase currents in the stationary coordinate system are... , Depend on , , Obtained by Clark transformation.

[0028] Step S12: Determine the reference active power compensation amount on the AC side based on the real-time grid frequency, wherein the reference active power compensation amount is used to characterize the active power compensation amount corresponding to the degree of deviation of the real-time grid frequency from the rated grid frequency.

[0029] In this step, the degree of deviation of the real-time grid frequency from the rated grid frequency reflects the instantaneous supply and demand imbalance of the grid's active power. If the real-time grid frequency is greater than the rated grid frequency, it indicates that the grid has a power surplus and the energy storage converter needs to absorb power. If the real-time grid frequency is less than the rated grid frequency, it indicates that the grid has a power deficit and the energy storage converter needs to inject power.

[0030] In some embodiments, when performing step S12, the frequency deviation is first determined based on the real-time grid frequency. The frequency deviation is equal to the difference between the preset reference grid frequency and the real-time grid frequency. Then, the reference active power compensation on the AC side is determined based on the frequency deviation and the frequency regulation droop coefficient. The reference active power compensation is equal to the product of the frequency deviation and the frequency regulation droop coefficient. The frequency regulation droop coefficient is determined based on the rated active power of the energy storage converter and the preset frequency regulation response frequency range.

[0031] For example, first calculate the frequency deviation. ,in The rated power grid frequency, The frequency is the real-time grid frequency. Then, based on the preset frequency droop coefficient... Calculate the baseline active power compensation amount FM droop factor Frequency modulation droop factor is used to characterize the amount of active power compensation required per unit frequency deviation, and its dimension is power / frequency. The rated active power of the energy storage converter and the preset frequency response range To be determined jointly.

[0032] In some embodiments, before determining the reference active power compensation amount on the AC side based on the frequency deviation and the frequency regulation droop coefficient, the rated active power, starting frequency, and ending frequency of the energy storage converter are first determined. The starting frequency is the frequency at which the energy storage converter begins to respond to frequency regulation, and the ending frequency is the frequency at which the energy storage converter reaches its rated active power output. The frequency difference is calculated based on the starting frequency and the ending frequency, and the frequency difference is equal to the absolute value of the difference between the ending frequency and the starting frequency. Finally, the frequency regulation droop coefficient is determined based on the rated active power and the frequency difference, and the frequency regulation droop coefficient is equal to the ratio of the rated active power to the frequency difference.

[0033] During the grid-connected commissioning phase of the energy storage converter, the rated active power, starting frequency, and ending frequency are pre-configured according to grid connection standards. Rated active power characterizes the maximum continuous active power output capability of the energy storage converter, determined by the equipment nameplate parameters. The starting frequency is the frequency at which the energy storage converter begins to respond to frequency regulation, i.e., the boundary frequency of the frequency regulation dead zone; the ending frequency is the frequency at which the energy storage converter reaches its rated active power output. For example, an energy storage converter with a rated active power of 10MW and a rated frequency... =50Hz, the frequency dead zone is ±0.05Hz, that is, the frequency dead zone boundaries are 49.95Hz and 50.05Hz; the full-load frequency value is ±0.5Hz, that is, 49.5Hz and 50.5Hz. The frequency difference on the under-frequency side = |49.5−49.95|=0.45Hz; the frequency difference on the over-frequency side = |50.5−50.05|=0.45Hz, then... =0.45Hz, the frequency difference on both sides is the same, FM droop coefficient = 10MW / 0.45Hz≈22.22MW / Hz consistent, ensuring that the energy storage converter has symmetrical frequency regulation response characteristics under both under-frequency and over-frequency operating conditions. Preset frequency regulation response range Pre-setting the frequency regulation droop coefficient according to grid connection standards for energy storage converters, such as GB / T 36547-2018 "Technical Regulations for Grid Connection of Electrochemical Energy Storage Systems", typically includes the frequency regulation dead zone range and the full-load frequency difference range. This step converts the grid frequency deviation into the active power compensation amount that the energy storage converter should output, thus realizing the primary frequency regulation function. This frequency regulation droop coefficient, after being set, is stored in the controller's non-volatile memory and remains unchanged during the operation of the energy storage converter.

[0034] Step S13: Based on the state of charge of the battery on the DC side of the energy storage converter, the reference active power compensation amount is corrected to obtain the actual active power compensation amount.

[0035] In this step, the battery state of charge (SOC) refers to the ratio of the battery's current remaining capacity to its maximum usable capacity, usually expressed as a percentage. The energy storage converter controller receives battery status data frames periodically sent by the battery management system via a CAN bus or RS485 communication interface, and parses the SOC value from these data frames. The SOC reflects the battery's current remaining capacity. When the SOC is close to its upper limit (>90%), the battery's charging capacity is severely limited; when the SOC is close to its lower limit (<10%), the battery's discharging capacity is severely limited. To protect the battery and ensure the energy storage system can continuously respond to frequency regulation commands, the baseline active power compensation amount needs to be dynamically limited based on the battery SOC.

[0036] In some embodiments, when performing step S13, firstly, a state of charge (SCC) limiting factor is determined based on the battery's SCC. The SCC limiting factor is used to characterize the degree of deviation of the battery's SCC from the target SCC. Then, the actual active power compensation amount is determined based on the SCC limiting factor and the reference active power compensation amount. The actual active power compensation amount is equal to the product of the SCC limiting factor and the reference active power compensation amount.

[0037] Optionally, state of charge constraint factor This is a dimensionless coefficient, with a value range of [0, 1]. Based on the battery's state of charge... Determine the state of charge constraint factor At that time, define the target state of charge. =50%, the preset allowable range of state of charge is: =[10%, 90%]. When the battery is at its state of charge... At [30%, 70%], the state-of-charge constraint factor =1, no limiting at all; when the battery is in state of charge At [10%, 30%), the state-of-charge constraint factor =(SOC-10%) / (30%-10%), which varies linearly between 0 and 1; when the battery's state of charge... State of charge constraint factor at (70%, 90%) =(90%-SOC) / (90%-70%), which varies linearly between 0 and 1; when the battery's state of charge... <10% or battery state of charge When >90%, the state-of-charge constraint factor =0, completely stopping power output in the corresponding direction. The thresholds for the piecewise linear function, such as 10%, 30%, 50%, 70%, and 90%, can be pre-tuned according to the battery's electrochemical characteristics and the protection thresholds of the battery management system (BMS). Different threshold parameters can be configured for different battery types. The reference active power compensation amount... Multiply by the state-of-charge constraint factor The actual active power compensation amount is obtained. .when When =1, The energy storage converter fully responds to frequency regulation requirements; when <1 hour, By limiting the amplitude of the frequency regulation response of the energy storage converter, the response amplitude is reduced, thereby protecting the battery. By correcting the reference active power compensation amount, the actual active power compensation amount can be obtained, which can achieve dynamic limiting of the power command by the battery's state of charge. When the battery's state of charge is within the safe range, it fully responds to frequency regulation, and automatically derates when the battery's state of charge approaches the extreme value, thus ensuring battery safety while maintaining frequency regulation capability to the maximum extent.

[0038] Step S14: Determine the rotor phase angle of the virtual synchronous generator based on the actual active power compensation amount, the real-time active power, the real-time reactive power, and the preset target reactive power.

[0039] In this step, the Virtual Synchronous Generator (VSG) is a technology that simulates the electromechanical transient characteristics of a traditional synchronous generator using a power electronic converter and its control algorithm. It endows grid-connected devices or energy storage systems for renewable energy sources such as photovoltaics and wind power with external characteristics such as inertia, damping, frequency, and voltage regulation, thereby transforming them from current sources to voltage sources and actively supporting grid stability. This step uses the actual active power compensation as the input to the active power loop of the VSG, compares it with the real-time active power to form the active power deviation, and converts this deviation into the rotor phase angle of the VSG by simulating the rotor motion equations of the VSG.

[0040] In some embodiments, when performing step S14, the active power deviation and reactive power deviation are first determined respectively. The active power deviation is equal to the difference between the actual active power compensation and the real-time active power, and the reactive power deviation is equal to the difference between the preset target reactive power and the real-time reactive power. Then, the equivalent mechanical power drive is determined based on the active power deviation and the reactive power feedback adjustment. The equivalent mechanical power drive is equal to the sum of the active power deviation and the reactive power feedback adjustment. The reactive power feedback adjustment is equal to the product of the reactive power deviation and the preset reactive power feedback coefficient. Then, the rate of change of the virtual rotor angular frequency is determined based on the equivalent mechanical power drive and the real-time grid angular frequency on the AC side. Finally, the rotor phase angle of the virtual synchronous generator is determined based on the rate of change of the virtual rotor angular frequency and the control cycle duration. The control cycle duration is determined based on the timer interrupt cycle of the energy storage converter.

[0041] For example, active power deviation An active power deviation > 0 indicates that active power output needs to be increased, while an active power deviation < 0 indicates that active power output needs to be decreased. Reactive power deviation... , A preset target reactive power is set, which is either issued by the battery management system or set automatically by the energy storage converter. It is typically set to 0 to achieve unity power factor operation. Then, the reactive power feedback adjustment is calculated. ,in A preset reactive power feedback coefficient is used, typically ranging from 0.1 to 0.5, determined based on system damping requirements. This reactive power feedback term couples the reactive power deviation into the active power rotor equation to suppress power oscillations. The purpose of introducing the preset reactive power feedback coefficient is to couple the reactive power deviation into the active power rotor motion equation, eliminating the influence of output voltage variations on active power control. Equivalent mechanical power drive quantity. Equivalent mechanical power drive quantity This can characterize the difference between the equivalent input mechanical power and the output electromagnetic power in the rotor motion equation of a virtual synchronous generator. The equivalent mechanical power drives the... Substituting the second-order rotor motion equation of the virtual synchronous generator, we get: Thus, the rate of change of the virtual rotor angular frequency is obtained: Where J is the virtual moment of inertia, in kg·m², which is set according to the capacity of the energy storage converter and the grid demand. The typical value range is 0.1 to 10 kg·m². The larger the virtual moment of inertia, the greater the inertia, but the longer the recovery time. The rated angular frequency corresponds to the rated frequency. , ; is the rate of change of the virtual rotor angular frequency; D is the damping coefficient, in N·m·s, which is tuned according to the system's oscillation suppression requirements, with a typical range of 10 to 500 N·m·s. The larger D is, the faster the oscillation decays. The virtual rotor angular frequency to be solved; This is the real-time angular frequency of the power grid.

[0042] Discretize and solve the above differential equation to control the period duration. If the frequency is equal to the PWM carrier period, such as 100μs, and is determined by the timer interrupt period, then the discrete update formula for the virtual rotor angular frequency is: The virtual rotor angular frequency of the current period is obtained. Afterwards, By performing time integration, the rotor phase angle of the virtual synchronous generator is obtained: Rotor phase angle of virtual synchronous generator This is the voltage phase reference output by the virtual synchronous generator. This step converts the actual active power compensation into the voltage phase reference of the virtual synchronous generator, enabling the energy storage converter to have inertial and damping characteristics similar to a synchronous generator, achieving smooth regulation and suppressing power oscillations when responding to changes in grid frequency.

[0043] Step S15: Determine the on / off state of each switch tube in the energy storage converter according to the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator, wherein the voltage amplitude reference value is determined according to the real-time reactive power and the preset target reactive power.

[0044] In this step, the three-phase sinusoidal modulation wave is composed of the virtual rotor phase angle θ and the voltage amplitude reference value. A joint decision.

[0045] In some embodiments, before executing step S15, the proportional adjustment amount and the current integral increment are first determined based on the reactive power deviation. The proportional adjustment amount is equal to the product of the reactive power deviation and the preset proportional gain coefficient, and the current integral increment is equal to the product of the reactive power deviation and the preset integral gain coefficient. The current voltage adjustment amount is determined based on the proportional adjustment amount and the current integral accumulation amount. The current voltage adjustment amount is equal to the sum of the proportional adjustment amount and the current integral accumulation amount, and the current integral accumulation amount is determined based on the current integral increment. The voltage amplitude reference value of the virtual synchronous generator is determined based on the current voltage adjustment amount and the preset rated voltage amplitude. The voltage amplitude reference value is equal to the sum of the current voltage adjustment amount and the rated voltage amplitude.

[0046] For example, when determining the proportional adjustment and the current integral increment based on the reactive power deviation, the adjustment is... ,in The preset proportional gain coefficient. The voltage regulation response speed is set according to the system's required voltage regulation speed, with a typical range of 0.1 to 10V / Var, and the current integral increment is... ,in The preset integral gain coefficient. Used to eliminate steady-state reactive power error, the typical value range is 0.01 to 1 V / (Var·s). The preset proportional gain coefficient and preset integral gain coefficient are set based on the reactive power-voltage droop characteristics of the energy storage converter and the system stability requirements, and are usually determined by frequency domain analysis methods, such as the gain margin and phase margin of the open-loop transfer function.

[0047] When determining the current voltage regulation based on the proportional adjustment and the current integral accumulation, the current voltage regulation... , This is the current accumulated score. ; This is the integral accumulation of the previous control cycle, with an initial value. When determining the voltage amplitude reference value based on the current voltage regulation and the preset rated voltage amplitude, the preset rated voltage amplitude... This refers to the amplitude of the rated output voltage of the energy storage converter. For example, a 400V system corresponds to a phase voltage amplitude of approximately 326V, determined by the system's rated voltage level. Voltage amplitude reference value. This step uses PI control to convert reactive power deviation into voltage amplitude commands, proportional regulation to ensure response speed, and integral regulation to eliminate steady-state error. The combination of these two methods achieves accurate control of reactive power at the grid connection point.

[0048] In some embodiments, when executing step S15, firstly, the phases of the A-phase modulation wave, B-phase modulation wave, and C-phase modulation wave are determined according to the rotor phase angle, with the phases of the A-phase modulation wave, B-phase modulation wave, and C-phase modulation wave differing by 120 electrical degrees in sequence; then, based on the voltage amplitude reference value, the A-phase modulation wave phase, B-phase modulation wave phase, and C-phase modulation wave phase, the current instantaneous values ​​of the A-phase modulation wave, B-phase modulation wave, and C-phase modulation wave are determined respectively; then, based on the current instantaneous values ​​of the A-phase modulation wave, B-phase modulation wave, C-phase modulation wave, and carrier signal, the on / off states of the A-phase upper bridge switch, B-phase upper bridge switch, and C-phase upper bridge switch are determined respectively; finally, based on the on / off states of the A-phase upper bridge switch, B-phase upper bridge switch, and C-phase upper bridge switch, the on / off states of the A-phase lower bridge switch, B-phase lower bridge switch, and C-phase lower bridge switch are determined respectively.

[0049] The rotor phase angle of the virtual synchronous generator represents the current electrical angle position of the virtual synchronous generator rotor. Phase A modulation wave phase. Phase B of the modulated wave Lagging phase A by 120°; phase C modulated wave phase The phase B lag is 120°.

[0050] Among them, the instantaneous value of the A-phase modulated wave Instantaneous value of phase B modulated wave Instantaneous value of the C-phase modulated wave They are respectively represented as ; ; The instantaneous value of the modulated wave is calculated by the controller in each control cycle.

[0051] When determining the on / off state of the upper bridge switch based on the instantaneous values ​​of the three-phase modulation wave and the carrier signal, the current instantaneous value of the carrier signal is first obtained. The carrier signal is generated by the time-base counter of the enhanced pulse width modulation module inside the controller. This counter increments and decrements at a preset carrier frequency, generating a periodically repeating triangular wave digital sequence. In each control cycle, the software reads the current value of the time-base counter, which is the current instantaneous value c(k) of the carrier signal. Then... , , The on / off states of the upper bridge switches in phases A, B, and C are determined by comparing them with c(k). The on / off states of the lower bridge switches in the same phase are opposite to those of the upper bridge switches; that is, when the upper bridge switch is on, the lower bridge switch is off, and when the upper bridge switch is off, the lower bridge switch is on. This is because the upper and lower bridge arms of the same phase are connected in series between the positive and negative poles of the DC bus, and if they are both on, it will cause a short circuit in the DC bus. The on / off states of the lower bridge switches are automatically generated by hardware logic, such as through the complementary output configuration of the enhanced pulse width modulation module, without the need for additional software calculations. This step establishes a complete calculation link from the rotor phase angle to the on / off states of each switch. The 120° phase difference between the three-phase modulated waves ensures the generation of symmetrical three-phase output voltages.

[0052] In some embodiments, when determining the on / off state of the A-phase, B-phase, and C-phase upper-bridge switches based on the current instantaneous values ​​of the A-phase modulation wave, B-phase, and C-phase modulation wave, and the carrier signal, respectively, if the current instantaneous value of the A-phase modulation wave is greater than the current instantaneous value of the carrier signal, the A-phase upper-bridge switch is determined to be on; otherwise, the A-phase upper-bridge switch is determined to be off. If the current instantaneous value of the B-phase modulation wave is greater than the current instantaneous value of the carrier signal, the B-phase upper-bridge switch is determined to be on; otherwise, the B-phase upper-bridge switch is determined to be off. If the current instantaneous value of the C-phase modulation wave is greater than the current instantaneous value of the carrier signal, the C-phase upper-bridge switch is determined to be on; otherwise, the C-phase upper-bridge switch is determined to be off.

[0053] The comparison operation described above is performed by the controller hardware comparator. The comparison result is automatically updated to the Action Qualifier submodule of the enhanced pulse width modulation module, requiring no software intervention and achieving microsecond-level response. Within a carrier cycle, the instantaneous value of the modulation wave can be considered a constant value. When the modulation wave amplitude is small, the proportion of time the instantaneous carrier value is greater than the instantaneous modulation wave value is larger, resulting in a longer turn-off time and a shorter turn-on time for the switching transistor, corresponding to a lower output voltage. When the modulation wave amplitude is large, the proportion of time the instantaneous carrier value is less than the instantaneous modulation wave value is larger, resulting in a longer turn-on time and a shorter turn-off time for the switching transistor, corresponding to a higher output voltage. This achieves a natural mapping of voltage commands to PWM pulse width. Within a complete carrier cycle, the cumulative proportion of the switching transistor's turn-on time is the duty cycle for that cycle. This duty cycle is the cumulative statistical result of the instantaneous comparison process on the time axis, rather than the control quantity directly output by the algorithm. For example, if the carrier period is 100μs, and phase A meets the conduction condition 65 times out of 100 comparisons, then the upper bridge switch of phase A is cumulatively conducted for 65μs within this carrier period, with a duty cycle of 65%. By comparing instantaneous values, a natural mapping of voltage amplitude commands to PWM pulse widths is achieved. The comparison result directly determines the on / off state of the switch, eliminating the need for additional duty cycle calculations, simplifying the control process, and reducing latency and software complexity.

[0054] Step S16: Generate a pulse width modulation signal according to the on / off state, and control the on / off state of each switch in the energy storage converter through the pulse width modulation signal.

[0055] In this step, the on / off state of each switch is written into the comparator register of the enhanced pulse width modulation (PWM) module inside the energy storage converter controller. Based on the value in the comparator register, the PWM module automatically generates a high-level or low-level signal on the corresponding output pin. It outputs a high level when the switch is on and a low level when it is off; these high and low level signals are the PWM pulse signals. After being optocoupled and amplified by the drive circuit, the PWM pulse signals are applied to the gates of the IGBTs or MOSFETs in each bridge arm of the three-phase inverter. A high level turns the power switching devices on, and a low level turns them off, thus achieving bidirectional conversion between DC and AC power. This step converts the on / off state into actual drive level signals to control the switching on and off of the power switching devices, realizing the conversion and transmission of electrical energy.

[0056] To implement the control method for the energy storage converter corresponding to the above method embodiments, in order to achieve the corresponding functions and technical effects, see [link to relevant documentation]. Figure 2 , Figure 2This diagram illustrates a structural block diagram of a control device for an energy storage converter according to an embodiment of this application. For ease of explanation, only the parts relevant to this embodiment are shown. The control device 20 for the energy storage converter provided in this embodiment includes: The first determining module 21 is used to determine the real-time grid frequency, real-time active power, and real-time reactive power of the AC side based on the three-phase voltage and three-phase current of the AC side of the energy storage converter; the second determining module 22 is used to determine the reference active power compensation amount of the AC side based on the real-time grid frequency, wherein the reference active power compensation amount is used to characterize the active power compensation amount corresponding to the degree of deviation of the real-time grid frequency from the rated grid frequency; the correction module 23 is used to correct the reference active power compensation amount based on the battery state of charge of the DC side of the energy storage converter to obtain the actual active power compensation amount; the third determining module 22 is used to determine the reference active power compensation amount based on the battery state of charge of the DC side of the energy storage converter to obtain the actual active power compensation amount; the third determining module 23 is used to determine the reference active power compensation amount based on the battery state of charge of the DC side of the energy storage converter to obtain the actual active power compensation amount. Module 24 is used to determine the rotor phase angle of the virtual synchronous generator based on the actual active power compensation, the real-time active power, the real-time reactive power, and the preset target reactive power; the fourth determining module 25 is used to determine the on / off state of each switch in the energy storage converter based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator, wherein the voltage amplitude reference value is determined based on the real-time reactive power and the preset target reactive power; the control module 26 is used to generate a pulse width modulation signal based on the on / off state, and control the on / off state of each switch in the energy storage converter through the pulse width modulation signal.

[0057] The control device for the energy storage converter described above can implement the control method for the energy storage converter in the above method embodiments. The options in the above method embodiments are also applicable to this embodiment, and will not be detailed here. The remaining content of this application embodiment can be referred to the content of the above method embodiments, and will not be repeated in this embodiment.

[0058] Figure 3 This is a schematic diagram of the structure of an energy storage converter provided in one embodiment of this application. Figure 3 As shown, the energy storage converter 30 of this embodiment includes: at least one processor 31 ( Figure 3 (Only one is shown in the diagram), memory 32, and computer program 33 stored in the memory 32 and executable on the at least one processor 31, wherein the processor 31 executes the computer program 33 to implement the steps in any of the above method embodiments.

[0059] The energy storage converter may include, but is not limited to, processor 31 and memory 32. Those skilled in the art will understand that... Figure 3This is merely an example of the energy storage converter 30 and does not constitute a limitation on the energy storage converter 30. It may include more or fewer components than shown, or combine certain components, or different components, such as input / output devices, network access devices, etc.

[0060] The processor 31 may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0061] In some embodiments, the memory 32 may be an internal storage unit of the energy storage converter 30. In other embodiments, the memory 32 may be an external storage device of the energy storage converter 30, such as a plug-in hard drive, smart media card (SMC), secure digital card (SD) card, flash card, etc., equipped on the energy storage converter 30. Furthermore, the memory 32 may include both internal storage units and external storage devices of the energy storage converter 30. The memory 32 is used to store operating systems, applications, boot loaders, data, and other programs, such as the program code of computer programs. The memory 32 can also be used to temporarily store data that has been output or will be output.

[0062] In addition, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps in any of the above method embodiments.

[0063] This application provides a computer program product that, when run on a computer device, enables the computer device to execute the steps described in the various method embodiments above.

[0064] In the several embodiments provided in this application, it will be understood that each block in the flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the figures. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved.

[0065] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0066] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application for those skilled in the art.

Claims

1. A control method for an energy storage converter, characterized in that, The method includes: Based on the three-phase voltage and three-phase current on the AC side of the energy storage converter, determine the real-time grid frequency, real-time active power, and real-time reactive power on the AC side. The reference active power compensation amount on the AC side is determined based on the real-time grid frequency, wherein the reference active power compensation amount is used to characterize the active power compensation amount corresponding to the degree of deviation of the real-time grid frequency from the rated grid frequency. Based on the state of charge of the battery on the DC side of the energy storage converter, the reference active power compensation amount is corrected to obtain the actual active power compensation amount. The rotor phase angle of the virtual synchronous generator is determined based on the actual active power compensation, the real-time active power, the real-time reactive power, and the preset target reactive power. Based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator, the on / off state of each switch in the energy storage converter is determined respectively, wherein the voltage amplitude reference value is determined based on the real-time reactive power and the preset target reactive power; A pulse width modulation signal is generated based on the on / off state, and the on / off state of each switch in the energy storage converter is controlled by the pulse width modulation signal.

2. The control method for the energy storage converter as described in claim 1, characterized in that, The step of determining the reference active power compensation amount on the AC side based on the real-time grid frequency includes: The frequency deviation is determined based on the real-time power grid frequency, wherein the frequency deviation is equal to the difference between a preset reference power grid frequency and the real-time power grid frequency. The reference active power compensation amount on the AC side is determined based on the frequency deviation and the frequency droop coefficient, wherein the reference active power compensation amount is equal to the product of the frequency deviation and the frequency droop coefficient, and the frequency droop coefficient is determined based on the rated active power of the energy storage converter and the preset frequency regulation response range.

3. The control method for the energy storage converter as described in claim 2, characterized in that, Before determining the reference active power compensation amount on the AC side based on the frequency deviation and the frequency modulation droop coefficient, the process includes: The rated active power, starting frequency, and ending frequency of the energy storage converter are determined, wherein the starting frequency is the frequency at which the energy storage converter begins to respond to frequency regulation, and the ending frequency is the frequency at which the energy storage converter reaches its rated active power output. The frequency difference is calculated based on the starting frequency and the ending frequency, and the frequency difference is equal to the absolute value of the difference between the ending frequency and the starting frequency. The frequency droop coefficient is determined based on the rated active power and the frequency difference, wherein the frequency droop coefficient is equal to the ratio of the rated active power to the frequency difference.

4. The control method for the energy storage converter as described in claim 1, characterized in that, The step of correcting the reference active power compensation amount based on the battery state of charge on the DC side of the energy storage converter to obtain the actual active power compensation amount includes: A state of charge (SCC) constraint factor is determined based on the battery SCC, and the SCC constraint factor is used to characterize the degree of deviation of the battery SCC from the target SCC. The actual active power compensation amount is determined based on the state of charge limitation factor and the reference active power compensation amount, wherein the actual active power compensation amount is equal to the product of the state of charge limitation factor and the reference active power compensation amount.

5. The control method for the energy storage converter as described in claim 1, characterized in that, The step of determining the rotor phase angle of the virtual synchronous generator based on the actual active power compensation, the real-time active power, the real-time reactive power, and the preset target reactive power includes: The active power deviation and reactive power deviation are determined separately, wherein the active power deviation is equal to the difference between the actual active power compensation and the real-time active power, and the reactive power deviation is equal to the difference between the preset target reactive power and the real-time reactive power. The equivalent mechanical power drive is determined based on the active power deviation and the reactive power feedback adjustment, wherein the equivalent mechanical power drive is equal to the sum of the active power deviation and the reactive power feedback adjustment, and the reactive power feedback adjustment is equal to the product of the reactive power deviation and the preset reactive power feedback coefficient. The rate of change of the virtual rotor angular frequency is determined based on the equivalent mechanical power drive quantity and the real-time grid angular frequency on the AC side. The rotor phase angle of the virtual synchronous generator is determined based on the rate of change of the virtual rotor angular frequency and the duration of the control cycle, wherein the duration of the control cycle is determined based on the timer interrupt cycle of the energy storage converter.

6. The control method for the energy storage converter as described in claim 5, characterized in that, Before determining the on / off state of each switch in the energy storage converter based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator, the method further includes: The proportional adjustment amount and the current integral increment are determined based on the reactive power deviation amount, wherein the proportional adjustment amount is equal to the product of the reactive power deviation amount and the preset proportional gain coefficient, and the current integral increment is equal to the product of the reactive power deviation amount and the preset integral gain coefficient. The current voltage adjustment is determined based on the proportional adjustment amount and the current integral accumulation amount, wherein the current voltage adjustment amount is equal to the sum of the proportional adjustment amount and the current integral accumulation amount, and the current integral accumulation amount is determined based on the current integral increment. Based on the current voltage regulation amount and the preset rated voltage amplitude, the voltage amplitude reference value of the virtual synchronous generator is determined, wherein the voltage amplitude reference value is equal to the sum of the current voltage regulation amount and the rated voltage amplitude.

7. The control method for the energy storage converter as described in claim 1, characterized in that, The step of determining the on / off state of each switch in the energy storage converter based on the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator includes: The A-phase modulation wave phase, B-phase modulation wave phase, and C-phase modulation wave phase are determined according to the rotor phase angle, wherein the A-phase modulation wave phase, the B-phase modulation wave phase, and the C-phase modulation wave phase are successively 120 electrical degrees apart; Based on the voltage amplitude reference value, the phase of the A-phase modulation wave, the phase of the B-phase modulation wave, and the phase of the C-phase modulation wave, the current instantaneous value of the A-phase modulation wave, the current instantaneous value of the B-phase modulation wave, and the current instantaneous value of the C-phase modulation wave are determined respectively. Based on the current instantaneous value of the A-phase modulation wave, the current instantaneous value of the B-phase modulation wave, the current instantaneous value of the C-phase modulation wave, and the current instantaneous value of the carrier signal, determine the on / off state of the A-phase bridge switch, the B-phase bridge switch, and the C-phase bridge switch, respectively. Based on the on / off states of the A-phase upper bridge switch, B-phase upper bridge switch, and C-phase upper bridge switch, the on / off states of the A-phase lower bridge switch, B-phase lower bridge switch, and C-phase lower bridge switch are determined respectively.

8. The control method for the energy storage converter as described in claim 7, characterized in that, The step of determining the on / off states of the A-phase, B-phase, and C-phase upper-bridge switches based on the current instantaneous values ​​of the A-phase modulation wave, the B-phase modulation wave, the C-phase modulation wave, and the carrier signal, respectively, includes: If the current instantaneous value of the A-phase modulation wave is greater than the current instantaneous value of the carrier signal, then the A-phase upper bridge switch is determined to be turned on; otherwise, the A-phase upper bridge switch is determined to be turned off. If the current instantaneous value of the B-phase modulation wave is greater than the current instantaneous value of the carrier signal, then the B-phase upper bridge switch is determined to be turned on; otherwise, the B-phase upper bridge switch is determined to be turned off. If the current instantaneous value of the C-phase modulation wave is greater than the current instantaneous value of the carrier signal, then the C-phase upper bridge switch is determined to be turned on; otherwise, the C-phase upper bridge switch is determined to be turned off.

9. A control device for an energy storage converter, characterized in that, The device includes: The first determining module is used to determine the real-time grid frequency, real-time active power and real-time reactive power of the AC side based on the three-phase voltage and three-phase current of the AC side of the energy storage converter. The second determining module is used to determine the reference active power compensation amount on the AC side based on the real-time grid frequency, wherein the reference active power compensation amount is used to characterize the active power compensation amount corresponding to the degree of deviation of the real-time grid frequency from the rated grid frequency. The correction module is used to correct the reference active power compensation amount based on the battery state of charge on the DC side of the energy storage converter to obtain the actual active power compensation amount. The third determining module is used to determine the rotor phase angle of the virtual synchronous generator based on the actual active power compensation amount, the real-time active power, the real-time reactive power and the preset target reactive power; The fourth determining module is used to determine the on / off state of each switch tube in the energy storage converter according to the rotor phase angle and the voltage amplitude reference value of the virtual synchronous generator, wherein the voltage amplitude reference value is determined according to the real-time reactive power and the preset target reactive power. The control module is used to generate a pulse width modulation signal based on the on / off state, and control the on / off state of each switch in the energy storage converter through the pulse width modulation signal.

10. An energy storage converter, characterized in that, It includes a processor and a memory, the memory being used to store a computer program, which, when executed by the processor, implements the control method for the energy storage converter as described in any one of claims 1 to 8.

Images