Control method and system for voltage-type network-forming energy storage converter

Abstract

The invention discloses a control method and system for a voltage type grid-forming energy storage converter, and belongs to the technical field of new energy grid-connected control. The control method provided by the invention comprises the following steps: aiming at each control link of the voltage-type network-construction-type energy storage converter, constructing a control model of each control link based on virtual excitation and a hybrid synchronization mode; calculating control parameters based on the control model; and according to the control parameters, controlling the voltage-type network-forming energy storage converter so as to suppress the fault current of the voltage-type network-forming energy storage converter. According to the invention, the flexible adjustment requirements of active / frequency and reactive / voltage in different short-circuit ratio access environments can be met, the broadband oscillation risk is reduced, and the power throughput flexibility advantage of the energy storage system is better played.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy grid-connected control, and more specifically, to a control method and system for a voltage-type grid-connected energy storage converter. Background Art

[0002] Renewable energy generation, represented by photovoltaic and wind power, is developing rapidly. However, the intermittent output fluctuations and low damping and inertia issues associated with large-scale grid-connected renewable energy pose new challenges to the safe and stable operation of power systems. Energy storage technology, with its inherent advantages of flexible power throughput and long-term energy storage, is gaining widespread application. Common energy storage technologies include mechanical, electromagnetic, and electrochemical energy storage.

[0003] Traditional energy storage converter control strategies rely on either a phase-locked loop (PLL) to measure grid phase information for synchronous control, using the Park transform to decouple active and reactive power, and controlling the power output by controlling the amplitude and phase of the injected current, thus presenting a current source characteristic. Alternatively, they utilize a power synchronization link for synchronous control, automatically generating a virtual phase angle by adjusting the active power / DC voltage. Both control modes have their own advantages in different access scenarios. Grid-following control is more suitable for operation in strong grids and facilitates power command tracking, while grid-forming control is more suitable for operation in weak grids and facilitates inertia and voltage support. Drawing on the advantages of both control strategies and the established excitation control modes of traditional synchronous generators, a control strategy is proposed that meets the requirements for flexible regulation of active power / frequency and reactive power / voltage in access environments with varying short-circuit ratios.

[0004] In the prior art:

[0005] Droop control uses the voltage amplitude and frequency output by the energy storage system as reference objects, measures and calculates the P and Q output by the energy storage system, and adjusts the voltage U and frequency f with the help of the droop characteristics under the decoupling of QU and Pf to maintain the voltage and frequency balance of the system. Typical control is as follows: Figure 1 As shown. The droop control relationship can be expressed as:

[0006]

[0007] Among them, f is the inverter output frequency, U is the inverter output voltage, P and Q are the actual output power of the inverter, f0 is the rated output frequency, U0 is the rated output voltage, P ref , Q ref Assume that K is the output power reference value. p is the Pf droop control coefficient, K q is the QU droop control coefficient.

[0008] The above technology mimics the external voltage and frequency regulation characteristics of synchronous generators Pf and QU, but does not reflect the internal characteristics of the synchronous generator's contribution to system inertia and damping. This results in poor inertia and damping characteristics of the grid-connected system, mediocre frequency stability, and weak load disturbance resistance. Summary of the Invention

[0009] In response to the above problems, the present invention proposes a control method for a voltage-type grid-type energy storage converter, comprising:

[0010] For each control link of the voltage-type grid-type energy storage converter, a control model for each control link is constructed based on virtual excitation and hybrid synchronization methods;

[0011] Calculating control parameters based on the control model;

[0012] The voltage-type grid-type energy storage converter is controlled using the control parameters to suppress the fault current of the voltage-type grid-type energy storage converter.

[0013] Optionally, each control link includes: a virtual frequency modulation control link, a power synchronization control link, a phase-locked synchronization control link, a hybrid synchronization control link, a virtual excitation control link, a voltage phasor limiting link, and a virtual impedance limiting link.

[0014] Optional control models for each control link include:

[0015] Virtual frequency modulation control model, power synchronization control model, phase-locked synchronization control model, hybrid synchronization control model, virtual excitation control model, voltage phasor limiting model and virtual impedance limiting model.

[0016] Optional, virtual frequency modulation control model, as follows:

[0017]

[0018] Where ΔP ref is the additional reference power, ω0 is the reference frequency, ω g is the measured frequency calculated by the phase-locked loop, ω deadzone To set the frequency dead zone, K p is the frequency modulation coefficient.

[0019] Optional, power synchronization control model, as follows:

[0020]

[0021] Among them, T j is the virtual inertia time constant, Δω PC P is the virtual angular velocity of the internal potential output of the converter power synchronization control link. mis the input mechanical power, P is the actual output active power of the converter, and P ref is the power reference command, ΔP ref is the additional reference power component, D is the damping coefficient, K D is the deviation magnification, T w is the time constant of the DC isolation link, T3 and T4 are the time constants of the phase shift link, and s is the Laplace operator.

[0022] Optional, phase-locked synchronous control model, as follows:

[0023]

[0024] Among them, Δω PLL The output of the internal potential virtual angular velocity of the converter phase-locked synchronous control link, T PLL K is the phase-locked synchronization delay time constant, pPLL is the phase-locked loop proportional control coefficient, K iPLL is the phase-locked loop integral control coefficient, U gq is the q-axis component of the grid-connected point voltage, and s is the Laplace operator.

[0025] Optional, hybrid synchronous control model, as follows:

[0026]

[0027] Where θ is the virtual phase angle of the internal potential, C PLL is the phase-locked synchronous control mixing coefficient, C PC is the power synchronization control mixing coefficient, Δω PLL The virtual angular velocity of the internal potential output by the phase-locked synchronous control link of the converter, ω0 is the reference frequency, Δω PC is the virtual angular velocity of the internal potential output by the converter power synchronization control link, and s is the Laplace operator.

[0028] Optional, virtual excitation control model, as follows:

[0029]

[0030] Among them, E m is the virtual internal potential amplitude of the converter output, K is the regulator gain, K v is the proportional-integral selection factor, T1 and T2 are the voltage regulator time constants, V * is the reference voltage of the excitation voltage regulator, V is the calculated actual voltage signal of the excitation voltage regulator, The d-axis current component injected into the grid by the converter, T′ d0 is the time constant of the excitation winding, x d is the synchronous reactance, x′ dis the d-axis transient reactance, and s is the Laplace operator.

[0031] Optional voltage phasor limiting model, including virtual internal potential constraints, as follows:

[0032]

[0033] Among them, U cd and U cq are the dq axis components of the virtual internal potential, U gd and U gq are the dq axis components of the grid connection point voltage, L is the filter inductance, I dLim , I qLim are the dq axis component amplitude limits of the converter output current, and ω is the Laplace operator.

[0034] Optional, virtual impedance limiting model, as follows:

[0035]

[0036] in, The final generated value of the virtual internal potential dq axis component, U cdqref is the intermediate reference value of the virtual internal potential dq axis component, I gdq is the dq axis component of the converter output current, I dqLim deadzone K is the setting value of the converter virtual impedance switching dead zone, pILim K is the proportional coefficient of the virtual impedance limiting link, iILim is the integral coefficient of the virtual impedance limiting link, and s is the Laplace operator.

[0037] On the other hand, the present invention also proposes a control system for a voltage-type grid-type energy storage converter, comprising:

[0038] An initial unit is used to construct a control model for each control link of the voltage-type grid-type energy storage converter based on virtual excitation and hybrid synchronization methods;

[0039] a calculation unit, configured to calculate control parameters based on the control model;

[0040] A control unit is used to control the voltage-type grid-type energy storage converter with the control parameters to suppress the fault current of the voltage-type grid-type energy storage converter.

[0041] Optionally, each control link includes: a virtual frequency modulation control link, a power synchronization control link, a phase-locked synchronization control link, a hybrid synchronization control link, a virtual excitation control link, a voltage phasor limiting link, and a virtual impedance limiting link.

[0042] Optional control models for each control link include:

[0043] Virtual frequency modulation control model, power synchronization control model, phase-locked synchronization control model, hybrid synchronization control model, virtual excitation control model, voltage phasor limiting model and virtual impedance limiting model.

[0044] Optional, virtual frequency modulation control model, as follows:

[0045]

[0046] Where ΔP ref is the additional reference power, ω0 is the reference frequency, ω g is the measured frequency calculated by the phase-locked loop, ω deadzone To set the frequency dead zone, K p is the frequency modulation coefficient.

[0047] Optional, power synchronization control model, as follows:

[0048]

[0049] Among them, T j is the virtual inertia time constant, Δω PC P is the virtual angular velocity of the internal potential output of the converter power synchronization control link. m is the input mechanical power, P is the actual output active power of the converter, and P ref is the power reference command, ΔP ref is the additional reference power component, D is the damping coefficient, K D is the deviation magnification, T w is the time constant of the DC isolation link, T3 and T4 are the time constants of the phase shift link, and s is the Laplace operator.

[0050] Optional, phase-locked synchronous control model, as follows:

[0051]

[0052] Among them, Δω PLL The virtual angular velocity of the internal potential output of the phase-locked synchronous control link of the converter, T PLL K is the phase-locked synchronization delay time constant, pPLL is the phase-locked loop proportional control coefficient, K iPLL is the phase-locked loop integral control coefficient, U gq is the q-axis component of the grid-connected point voltage, and s is the Laplace operator.

[0053] Optional, hybrid synchronous control model, as follows:

[0054]

[0055] Where θ is the virtual phase angle of the internal potential, C PLL is the phase-locked synchronous control mixing coefficient, C PC is the power synchronization control mixing coefficient, Δω PLL The virtual angular velocity of the internal potential output by the phase-locked synchronous control link of the converter, ω0 is the reference frequency, Δω PC is the virtual angular velocity of the internal potential output by the converter power synchronization control link, and s is the Laplace operator.

[0056] Optional, virtual excitation control model, as follows:

[0057]

[0058] Among them, E m is the virtual internal potential amplitude of the converter output, K is the regulator gain, K v is the proportional-integral selection factor, T1 and T2 are the voltage regulator time constants, V * is the reference voltage of the excitation voltage regulator, V is the calculated actual voltage signal of the excitation voltage regulator, The d-axis current component injected into the grid by the converter, T′ d0 is the time constant of the excitation winding, x d is the synchronous reactance, x′ d is the d-axis transient reactance, and s is the Laplace operator.

[0059] Optional voltage phasor limiting model, including virtual internal potential constraints, as follows:

[0060]

[0061] Among them, U cd and U cq are the dq axis components of the virtual internal potential, U gd and U gq are the dq axis components of the grid connection point voltage, L is the filter inductance, I dLim , I qLim are the dq axis component amplitude limits of the converter output current, and ω is the Laplace operator.

[0062] Optional, virtual impedance limiting model, as follows:

[0063]

[0064] in, The final generated value of the virtual internal potential dq axis component, U cdqref is the intermediate reference value of the virtual internal potential dq axis component, I gdq is the dq axis component of the converter output current, IdqLim deadzone K is the setting value of the converter virtual impedance switching dead zone, pILim K is the proportional coefficient of the virtual impedance limiting link, iILim is the integral coefficient of the virtual impedance limiting link, and s is the Laplace operator.

[0065] In yet another aspect, the present invention further provides a computing device comprising: one or more processors;

[0066] a processor for executing one or more programs;

[0067] When the one or more programs are executed by the one or more processors, the above-described method is implemented.

[0068] In another aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the method described above is implemented.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] The present invention provides a control method for a voltage-grid-type energy storage converter, comprising: constructing a control model for each control link of the voltage-grid-type energy storage converter based on virtual excitation and hybrid synchronization; calculating control parameters based on the control model; and controlling the voltage-grid-type energy storage converter using the control parameters to suppress fault current in the voltage-grid-type energy storage converter. The present invention can meet the requirements for flexible regulation of active power / frequency and reactive power / voltage in access environments with different short-circuit ratios, reduce the risk of broadband oscillation, and better leverage the power throughput flexibility advantages of energy storage systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 This is the droop control block diagram;

[0072] Figure 2 is a flow chart of the method of the present invention;

[0073] Figure 3 This is a control block diagram of a grid-type energy storage converter according to the method of the present invention;

[0074] Figure 4 It is a structural diagram of the system of the present invention. DETAILED DESCRIPTION

[0075] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a thorough and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0076] Unless otherwise specified, the terms used herein (including technical terms) have the meanings commonly understood by those skilled in the art. In addition, it is understood that terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0077] Example 1:

[0078] The present invention proposes a control method for a voltage-type grid-type energy storage converter, such as Figure 2 Shown, including:

[0079] Step 1: For each control link of the voltage-type grid-type energy storage converter, a control model of each control link is constructed based on virtual excitation and hybrid synchronization methods;

[0080] Step 2: Calculate control parameters based on the control model;

[0081] Step 3: Control the voltage-type grid-type energy storage converter with the control parameters to suppress the fault current of the voltage-type grid-type energy storage converter.

[0082] Among them, the various control links include: virtual frequency modulation control link, power synchronization control link, phase-locked synchronization control link, hybrid synchronization control link, virtual excitation control link, voltage phasor limiting link and virtual impedance limiting link.

[0083] Among them, the control models of each control link include:

[0084] Virtual frequency modulation control model, power synchronization control model, phase-locked synchronization control model, hybrid synchronization control model, virtual excitation control model, voltage phasor limiting model and virtual impedance limiting model.

[0085] Among them, the virtual frequency modulation control model is as follows:

[0086]

[0087] Where ΔP ref is the additional reference power, ω0 is the reference frequency, ω gis the measured frequency calculated by the phase-locked loop, ω deadzone To set the frequency dead zone, K p is the frequency modulation coefficient.

[0088] Among them, the power synchronization control model is as follows:

[0089]

[0090] Among them, T j is the virtual inertia time constant, Δω PC P is the virtual angular velocity of the internal potential output of the converter power synchronization control link. m is the input mechanical power, P is the actual output active power of the converter, and P ref is the power reference command, ΔP ref is the additional reference power component, D is the damping coefficient, K D is the deviation magnification, T w is the time constant of the DC isolation link, T3 and T4 are the time constants of the phase shift link, and s is the Laplace operator.

[0091] Among them, the phase-locked synchronous control model is as follows:

[0092]

[0093] Among them, Δω PLL The virtual angular velocity of the internal potential output of the phase-locked synchronous control link of the converter, T PLL K is the phase-locked synchronization delay time constant, pPLL is the phase-locked loop proportional control coefficient, K iPLL is the phase-locked loop integral control coefficient, U gq is the q-axis component of the grid-connected point voltage, and s is the Laplace operator.

[0094] Among them, the hybrid synchronous control model is as follows:

[0095]

[0096] Where θ is the virtual phase angle of the internal potential, C PLL is the phase-locked synchronous control mixing coefficient, C PC is the power synchronization control mixing coefficient, Δω PLL The virtual angular velocity of the internal potential output by the phase-locked synchronous control link of the converter, ω0 is the reference frequency, Δω PC is the virtual angular velocity of the internal potential output by the converter power synchronization control link, and s is the Laplace operator.

[0097] Among them, the virtual excitation control model is as follows:

[0098]

[0099] Among them, E m is the virtual internal potential amplitude of the converter output, K is the regulator gain, K v is the proportional-integral selection factor, T1 and T2 are the voltage regulator time constants, V * is the reference voltage of the excitation voltage regulator, V is the calculated actual voltage signal of the excitation voltage regulator, The d-axis current component injected into the grid by the converter, T′ d0 is the time constant of the excitation winding, x d is the synchronous reactance, x′ d is the d-axis transient reactance, and s is the Laplace operator.

[0100] The voltage phasor limiting model includes the following virtual internal potential constraints:

[0101]

[0102] Among them, U cd and U cq are the dq axis components of the virtual internal potential, U gd and U gq are the dq axis components of the grid connection point voltage, L is the filter inductance, I dLim , I qLim are the dq axis component amplitude limits of the converter output current, and ω is the Laplace operator.

[0103] Among them, the virtual impedance limiting model is as follows:

[0104]

[0105] in, The final generated value of the virtual internal potential dq axis component, U cdqref is the intermediate reference value of the virtual internal potential dq axis component, I gdq is the dq axis component of the converter output current, I dqLim deadzone K is the setting value of the converter virtual impedance switching dead zone, pILim K is the proportional coefficient of the virtual impedance limiting link, iILim is the integral coefficient of the virtual impedance limiting link, and s is the Laplace operator.

[0106] The present invention will be further described below with reference to specific implementation cases of the present invention:

[0107] The present invention mainly adopts virtual excitation control in the energy storage converter to generate the virtual internal potential amplitude, and adopts a hybrid synchronization method of phase-locked loop and power synchronization control to generate the virtual internal potential phase angle; at the same time, a direct voltage structure without current inner loop is adopted, and virtual impedance and voltage phasor limiting are combined to achieve fault current suppression;

[0108] It can meet the flexible adjustment requirements of active power / frequency and reactive power / voltage under different short-circuit ratio access environments, reduce the risk of broadband oscillation, and has the ability to support system strength, self-synchronous operation, and isolated networking, effectively improving the stability of the "dual-high" power system.

[0109] Specific control link strategies, such as Figure 3 Shown, including:

[0110] (1) Virtual frequency regulation control link. Simulate the speed regulator characteristics of the synchronous generator set prime mover and simplify its active power-frequency characteristics. The converter detects the actual frequency of the power grid through the phase-locked loop and compares it with the reference frequency. After passing through the dead zone control module, if the speed deviation exceeds the set dead zone, the output is the deviation amount exceeding the dead zone; otherwise, the output is 0. The output frequency deviation is multiplied by the frequency regulation coefficient to obtain the power reference value addition. The virtual frequency regulation control model is expressed as follows:

[0111]

[0112] Where ΔP ref is the additional reference power; ω0 is the reference frequency; ω g is the measured frequency calculated by the phase-locked loop; ω deadzone To set the frequency dead zone; K p It is the frequency modulation coefficient, which is flexibly selected to adapt to system requirements and energy storage operating conditions.

[0113] (2) Power synchronization control link. Simulate the synchronous generator rotor motion equation, introduce inertia and damping links in the control, and enhance the active support capability of the converter. The sum of the additional reference power obtained by the virtual frequency modulation control link and the active reference instruction is used as the converter virtual mechanical power, and the actual output active power of the converter is used as the virtual electromagnetic power. The difference between the two is obtained after passing through the power synchronization control link to obtain the virtual speed of the energy storage converter. The control model is expressed as follows:

[0114]

[0115] Among them, T j is the virtual inertia time constant, which is flexibly selected to adapt to system requirements and energy storage operating conditions; Δω PC Output of internal potential virtual angular velocity for converter power synchronization control link; P m is the input mechanical power corresponding to the traditional synchronous machine; P is the actual output active power of the converter, which is determined by the active reference instruction P ref and additional reference power ΔP refThe damping feedback consists of two parts. The first part consists of an amplification link, which feeds back the steady-state frequency deviation. D is the damping coefficient. The second part consists of an amplification link, a DC isolation link, and a lead-lag link in series, which only feeds back the transient frequency deviation. K D is the deviation magnification, T w is the time constant of the DC isolation link, T3 and T4 are the time constants of the phase shift link.

[0116] (3) Phase-locked synchronization control link. The phase-locked loop collects the grid connection point voltage, locks and tracks the grid connection point phase, and realizes the synchronous operation of the energy storage unit and the grid. The control model is expressed as follows:

[0117]

[0118] Among them, Δω PLL Output internal potential virtual angular velocity for the converter phase-locked synchronous control link; T PLL K is the phase-locked synchronization delay time constant; pPLL is the proportional control coefficient of the phase-locked loop; K iPLL is the integral control coefficient of the phase-locked loop; U gq is the q-axis component of the grid-connected point voltage.

[0119] (4) Hybrid synchronous control link. Based on the difference between the power synchronous control link and the phase-locked synchronous control link, a hybrid coefficient is introduced to fuse the output angular velocity of the power synchronous link with the output angular velocity of the phase-locked synchronous link to achieve hybrid synchronous control. The control model is expressed as follows:

[0120]

[0121] Where θ is the virtual phase angle of the internal potential; C PLL is the phase-locked synchronous control mixing coefficient; C PC The power synchronization control mixing coefficient should be able to be adaptively adjusted according to the short-circuit ratio of the access system, and the value range of the mixing coefficient under different short-circuit ratios can be determined by combining various oscillation risk instability criteria.

[0122] (5) Virtual excitation control link. Simulate the characteristics of the synchronous generator excitation system and introduce the electromagnetic equations in the third-order practical model of the synchronous generator to accurately simulate the excitation dynamic characteristics:

[0123]

[0124] Among them, T′ d0 is the time constant of the excitation winding; E′ q is the transient potential; E qe is the forced no-load electromotive force that is linearly related to the excitation voltage; i d is the d-axis current component; x dis the synchronous reactance; x′ d is the d-axis transient reactance.

[0125] First, the voltage and current at the output of the energy storage converter are collected, and after the difference adjustment link, the actual voltage signal of the virtual excitation voltage regulator is obtained:

[0126]

[0127] Where V is the calculated actual voltage signal of the virtual excitation voltage regulator; T R is the filter time constant; U g is the grid connection point voltage; I g is the converter output current; R C is the differential resistance, X C The differential reactance is adjusted to give the virtual control system an appropriate differential characteristic. The introduction of this differential adjustment link can prevent oscillation caused by the simultaneous adjustment of the bus voltage by parallel-operating generating equipment.

[0128] The actual value of the voltage signal is then compared with the reference value, and the series PID control method is used to adjust the gain and dynamic characteristics of the virtual excitation control link. The control model is expressed as follows:

[0129]

[0130] Among them, E m is the virtual internal potential amplitude of the converter output, corresponding to the transient potential E′ q ; K is the regulator gain; K v is the proportional integral selection factor; T1 and T2 are the time constants of the voltage regulator; V * is the reference voltage of the excitation voltage regulator; V is the calculated actual voltage signal of the excitation voltage regulator; i gd The d-axis current component injected into the grid by the converter corresponds to i d .

[0131] (6) Voltage phasor limiting link. The fault current is suppressed by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage. Taking the self-generated phase of the converter as the reference coordinate system, the grid connection point voltage, virtual internal potential, and converter output current are projected onto this reference coordinate system to obtain the converter output current constraint condition:

[0132]

[0133] Among them, I gd , I gq are the dq axis components of the converter output current respectively; I dLim , I qLim are the dq axis component amplitude limits of the converter output current respectively; I maxis the total current limit value.

[0134] From this we can get the virtual internal potential constraint condition:

[0135]

[0136] Among them, U cd 、U cq are the dq axis components of the virtual internal potential respectively; U gd 、U gq are the dq axis components of the grid connection point voltage respectively; L is the filter inductance, and the filter resistance is ignored here. Figure 3 As shown, the virtual inner potential phasor E generated by the outer loop m ∠θ should be kept within the inner potential constraint circle, and the output voltage reference value is U cdref 、U cqref .

[0137] (7) Virtual impedance limiting link. The virtual impedance switching method is used to increase the output impedance of the energy storage converter and limit the transient impact current component during the fault. The virtual impedance control model is expressed as follows:

[0138]

[0139] in, The final generated value of the virtual internal potential dq axis component, U cdqref is the intermediate reference value of the virtual internal potential dq axis component; I gdq is the dq axis component of the converter output current, I dqLim deadzone K is the setting value of the converter virtual impedance switching dead zone; pILim K is the proportional coefficient of the virtual impedance limiting link; iILim is the integral coefficient of the virtual impedance limiting link.

[0140] Then the output signal is controlled by the internal potential according to the virtual phase angle θ An inverse Park transform is performed to obtain a voltage reference wave in the three-phase stationary coordinate system. This wave is then used to generate trigger pulses that meet control requirements through a PWM generator, completing overall output control. Because this overall control system lacks an inner current loop, the converter's high-frequency output impedance is dominated by the filter, reducing the risk of broadband oscillations introduced by the control characteristics.

[0141] Example 2:

[0142] The present invention also proposes a control system 200 for a voltage-type grid-type energy storage converter, such as Figure 4 Shown, including:

[0143] The initialization unit 201 is used to construct a control model for each control link of the voltage-type grid-type energy storage converter based on virtual excitation and hybrid synchronization methods;

[0144] A calculation unit 202 is configured to calculate control parameters based on the control model;

[0145] The control unit 203 is configured to control the voltage-type grid-type energy storage converter using the control parameters to suppress the fault current of the voltage-type grid-type energy storage converter.

[0146] Among them, the various control links include: virtual frequency modulation control link, power synchronization control link, phase-locked synchronization control link, hybrid synchronization control link, virtual excitation control link, voltage phasor limiting link and virtual impedance limiting link.

[0147] Among them, the control models of each control link include:

[0148] Virtual frequency modulation control model, power synchronization control model, phase-locked synchronization control model, hybrid synchronization control model, virtual excitation control model, voltage phasor limiting model and virtual impedance limiting model.

[0149] Among them, the virtual frequency modulation control model is as follows:

[0150]

[0151] Where ΔP ref is the additional reference power, ω0 is the reference frequency, ω g is the measured frequency calculated by the phase-locked loop, ω deadzone To set the frequency dead zone, K p is the frequency modulation coefficient.

[0152] Among them, the power synchronization control model is as follows:

[0153]

[0154] Among them, T j is the virtual inertia time constant, Δω PC P is the virtual angular velocity of the internal potential output of the converter power synchronization control link. m is the input mechanical power, P is the actual output active power of the converter, and P ref is the power reference command, ΔP ref is the additional reference power component, D is the damping coefficient, K D is the deviation magnification, T w is the time constant of the DC isolation link, T3 and T4 are the time constants of the phase shift link, and s is the Laplace operator.

[0155] Among them, the phase-locked synchronous control model is as follows:

[0156]

[0157] Among them, Δω PLL The output of the internal potential virtual angular velocity of the converter phase-locked synchronous control link, T PLL K is the phase-locked synchronization delay time constant, pPLL is the phase-locked loop proportional control coefficient, K iPLL is the phase-locked loop integral control coefficient, U gq is the q-axis component of the grid-connected point voltage, and s is the Laplace operator.

[0158] Among them, the hybrid synchronous control model is as follows:

[0159]

[0160] Where θ is the virtual phase angle of the internal potential, C PLL is the phase-locked synchronous control mixing coefficient, C PC is the power synchronization control mixing coefficient, Δω PLL The virtual angular velocity of the internal potential output by the phase-locked synchronous control link of the converter, ω0 is the reference frequency, Δω PC is the virtual angular velocity of the internal potential output by the converter power synchronization control link, and s is the Laplace operator.

[0161] Among them, the virtual excitation control model is as follows:

[0162]

[0163] Among them, E m is the virtual internal potential amplitude of the converter output, K is the regulator gain, K v is the proportional-integral selection factor, T1 and T2 are the voltage regulator time constants, V * is the reference voltage of the excitation voltage regulator, V is the calculated actual voltage signal of the excitation voltage regulator, The d-axis current component injected into the grid by the converter, T′ d0 is the time constant of the excitation winding, x d is the synchronous reactance, x′ d is the d-axis transient reactance, and s is the Laplace operator.

[0164] The voltage phasor limiting model includes the following virtual internal potential constraints:

[0165]

[0166] Among them, U cd and U cqare the dq axis components of the virtual internal potential, U gd and U gq are the dq axis components of the grid connection point voltage, L is the filter inductance, I dLim , I qLim are the dq axis component amplitude limits of the converter output current, and ω is the Laplace operator.

[0167] Among them, the virtual impedance limiting model is as follows:

[0168]

[0169] in, The final generated value of the virtual internal potential dq axis component, U cdqref is the intermediate reference value of the virtual internal potential dq axis component, I gdq is the dq axis component of the converter output current, I dqLim deadzone K is the setting value of the converter virtual impedance switching dead zone, pILim K is the proportional coefficient of the virtual impedance limiting link, iILim is the integral coefficient of the virtual impedance limiting link, and s is the Laplace operator.

[0170] The present invention can meet the requirements for flexible regulation of active power / frequency and reactive power / voltage under different short-circuit ratio access environments, reduce the risk of broadband oscillation, and better leverage the power throughput flexibility advantage of the energy storage system.

[0171] Example 3:

[0172] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the method in the above embodiment.

[0173] Example 4:

[0174] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It can be understood that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space that stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the method in the above embodiment.

[0175] It will be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention may be implemented in various computer languages, for example, the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0176] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0177] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0178] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0179] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0180] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A control method for a voltage-type grid-type energy storage converter, characterized in that: include: For each control link of the voltage-type grid-type energy storage converter, a control model for each control link is constructed based on virtual excitation and hybrid synchronization methods; Calculating control parameters based on the control model; The voltage-type grid-type energy storage converter is controlled using the control parameters to suppress the fault current of the voltage-type grid-type energy storage converter.

2. The control method according to claim 1, characterized in that: The various control links include: a virtual frequency modulation control link, a power synchronization control link, a phase-locked synchronization control link, a hybrid synchronization control link, a virtual excitation control link, a voltage phasor limiting link, and a virtual impedance limiting link.

3. The control method according to claim 1, wherein: The control models of the various control links include: Virtual frequency modulation control model, power synchronization control model, phase-locked synchronization control model, hybrid synchronization control model, virtual excitation control model, voltage phasor limiting model and virtual impedance limiting model.

4. The control method according to claim 3, characterized in that: The virtual frequency modulation control model is as follows: Where ΔP ref is the additional reference power, ω0 is the reference frequency, ω g is the measured frequency calculated by the phase-locked loop, ω deadzone To set the frequency dead zone, K p is the frequency modulation coefficient.

5. The control method according to claim 3, characterized in that: The power synchronization control model is as follows: Among them, T j is the virtual inertia time constant, Δω PC P is the virtual angular velocity of the internal potential output of the converter power synchronization control link. m is the input mechanical power, P is the actual output active power of the converter, and P ref is the power reference command, ΔP ref is the additional reference power component, D is the damping coefficient, K D is the deviation magnification, T w is the time constant of the DC isolation link, T3 and T4 are the time constants of the phase shift link, and s is the Laplace operator.

6. The control method according to claim 3, characterized in that: The phase-locked synchronous control model is as follows: Among them, Δω PLL The output of the internal potential virtual angular velocity of the converter phase-locked synchronous control link, T PLL K is the phase-locked synchronization delay time constant, pPLL is the phase-locked loop proportional control coefficient, K iPLL is the phase-locked loop integral control coefficient, U gq is the q-axis component of the grid-connected point voltage, and s is the Laplace operator.

7. The control method according to claim 3, characterized in that: The hybrid synchronous control model is as follows: Where θ is the virtual phase angle of the internal potential, C PLL is the phase-locked synchronous control mixing coefficient, C PC is the power synchronization control mixing coefficient, Δω PLL The virtual angular velocity of the internal potential output by the phase-locked synchronous control link of the converter, ω0 is the reference frequency, Δω PC is the virtual angular velocity of the internal potential output by the converter power synchronization control link, and s is the Laplace operator.

8. The control method according to claim 3, characterized in that: The virtual excitation control model is as follows: Among them, E m is the virtual internal potential amplitude of the converter output, K is the regulator gain, K v is the proportional-integral selection factor, T1 and T2 are the voltage regulator time constants, V * is the reference voltage of the excitation voltage regulator, V is the calculated actual voltage signal of the excitation voltage regulator, The d-axis current component injected into the grid by the converter, T′ d0 is the time constant of the excitation winding, x d is the synchronous reactance, x′ d is the d-axis transient reactance, and s is the Laplace operator.

9. The control method according to claim 3, characterized in that: The voltage phasor limiting model includes virtual internal potential constraints as follows: Among them, U cd and U cq are the dq axis components of the virtual internal potential, U gd and U gq are the dq axis components of the grid connection point voltage, L is the filter inductance, I dLim , I qLim are the dq axis component amplitude limits of the converter output current, and ω is the Laplace operator.

10. The control method according to claim 3, characterized in that: The virtual impedance limiting model is as follows: in, The final generated value of the virtual internal potential dq axis component, U cdqref is the intermediate reference value of the virtual internal potential dq axis component, I gdq is the dq axis component of the converter output current, I dqLimdeadzone K is the setting value of the converter virtual impedance switching dead zone, pILim K is the proportional coefficient of the virtual impedance limiting link, iILim is the integral coefficient of the virtual impedance limiting link, and s is the Laplace operator.

11. A control system for a voltage-type grid-type energy storage converter, characterized in that: include: An initial unit is used to construct a control model for each control link of the voltage-type grid-type energy storage converter based on virtual excitation and hybrid synchronization methods; a calculation unit, configured to calculate control parameters based on the control model; A control unit is used to control the voltage-type grid-type energy storage converter with the control parameters to suppress the fault current of the voltage-type grid-type energy storage converter.

12. The control system according to claim 11, characterized in that: The various control links include: a virtual frequency modulation control link, a power synchronization control link, a phase-locked synchronization control link, a hybrid synchronization control link, a virtual excitation control link, a voltage phasor limiting link, and a virtual impedance limiting link.

13. The control system according to claim 11, characterized in that: The control models of the various control links include: Virtual frequency modulation control model, power synchronization control model, phase-locked synchronization control model, hybrid synchronization control model, virtual excitation control model, voltage phasor limiting model and virtual impedance limiting model.

14. The control system according to claim 13, characterized in that: The virtual frequency modulation control model is as follows: Where ΔP ref is the additional reference power, ω0 is the reference frequency, ω g is the measured frequency calculated by the phase-locked loop, ω deadzone To set the frequency dead zone, K p is the frequency modulation coefficient.

15. The control system according to claim 13, characterized in that: The power synchronization control model is as follows: Among them, T j is the virtual inertia time constant, Δω PC P is the virtual angular velocity of the internal potential output of the converter power synchronization control link. m is the input mechanical power, P is the actual output active power of the converter, and P ref is the power reference command, ΔP ref is the additional reference power component, D is the damping coefficient, K D is the deviation magnification, T w is the time constant of the DC isolation link, T3 and T4 are the time constants of the phase shift link, and s is the Laplace operator.

16. The control system according to claim 13, characterized in that: The phase-locked synchronous control model is as follows: Among them, Δω PLL The virtual angular velocity of the internal potential output of the phase-locked synchronous control link of the converter, T PLL K is the phase-locked synchronization delay time constant, pPLL is the phase-locked loop proportional control coefficient, K iPLL is the phase-locked loop integral control coefficient, U gq is the q-axis component of the grid-connected point voltage, and s is the Laplace operator.

17. The control system according to claim 13, characterized in that: The hybrid synchronous control model is as follows: Where θ is the virtual phase angle of the internal potential, C PLL is the phase-locked synchronous control mixing coefficient, C PC is the power synchronization control mixing coefficient, Δω PLL The virtual angular velocity of the internal potential output by the phase-locked synchronous control link of the converter, ω0 is the reference frequency, Δω PC is the virtual angular velocity of the internal potential output by the converter power synchronization control link, and s is the Laplace operator.

18. The control system according to claim 13, characterized in that: The virtual excitation control model is as follows: Among them, E m is the virtual internal potential amplitude of the converter output, K is the regulator gain, K v is the proportional-integral selection factor, T1 and T2 are the voltage regulator time constants, V * is the reference voltage of the excitation voltage regulator, V is the calculated actual voltage signal of the excitation voltage regulator, The d-axis current component injected into the grid by the converter, T′ d0 is the time constant of the excitation winding, x d is the synchronous reactance, x′ d is the d-axis transient reactance, and s is the Laplace operator.

19. The control system according to claim 13, characterized in that The voltage phasor limiting model includes virtual internal potential constraints as follows: Among them, U cd and U cq are the dq axis components of the virtual internal potential, U gd and U gq are the dq axis components of the grid connection point voltage, L is the filter inductance, I dLim , I qLim are the dq axis component amplitude limits of the converter output current, and ω is the Laplace operator.

20. The control system according to claim 13, characterized in that The virtual impedance limiting model is as follows: in, The final generated value of the virtual internal potential dq axis component, U cdqref is the intermediate reference value of the virtual internal potential dq axis component, I gdq is the dq axis component of the converter output current, I dqLimdeadzone K is the setting value of the converter virtual impedance switching dead zone, pILim K is the proportional coefficient of the virtual impedance limiting link, iILim is the integral coefficient of the virtual impedance limiting link, and s is the Laplace operator.

21. A computer device, characterized in that: include: one or more processors; a processor for executing one or more programs; When the one or more programs are executed by the one or more processors, the method according to any one of claims 1 to 10 is implemented.

22. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed, the method according to any one of claims 1 to 10 is implemented.

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