Active support control method and system for static phase modifier based on virtual excitation control

Abstract

The invention provides a static phase modifier active support control method and system based on virtual excitation control. The method comprises the steps that in a power electronic converter, virtual excitation control is adopted to generate a virtual internal potential amplitude, and a phase-locked loop and power synchronous control mixed synchronization mode is adopted to generate a virtual internal potential phase angle; and meanwhile, a direct voltage type structure without a current inner loop is adopted, and virtual impedance and voltage phasor amplitude limiting are combined to realize fault current suppression, so that inertia support and voltage support can be provided for a power grid, the short-circuit ratio of a grid-connected point is improved, and the stability of the system is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of new energy grid-connected control, and in particular to a method and system for active support control of a static phase regulator based on virtual excitation control. Background Art

[0002] The intermittent output fluctuations and low damping and low inertia problems of large-scale renewable energy grid connection have brought new challenges to the safe and stable operation of the power system.

[0003] Traditional reactive power compensation equipment can be divided into two categories: rotating and static. Rotating reactive power compensation devices, such as synchronous phase regulators, can quickly provide or absorb reactive power to the power system when needed to maintain voltage stability. They are widely used in scenarios such as new energy stations and hub substations. However, they suffer from high operating losses, high operating costs, and slow response speeds. Static reactive power compensation devices, represented by the static VAR generator (SVG), use power electronics technology to control the output current of the device to achieve reactive power control. They offer faster response speeds and greater control accuracy. However, this strategy is limited by the phase-locked loop (PLL) grid-connected method, resulting in a passive response mode that is not conducive to active support of reactive power and voltage in the system. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention draws on the advantages of two types of traditional reactive power compensation equipment, namely rotating and static types, and the mature excitation control mode of traditional synchronous generators. The present invention provides an active support control method for a static phase condenser based on virtual excitation control, comprising:

[0005] The DC voltage control link obtains the deviation between the actual DC voltage value and the reference value, and controls the deviation through virtual frequency modulation to obtain the power reference value addition;

[0006] The power synchronization control link uses the sum of the power reference value addition and the active reference power as the converter virtual mechanical power, and the difference between the virtual mechanical power and the virtual electromagnetic power is passed through the power synchronization control link to obtain the converter virtual speed;

[0007] 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 unit and the grid;

[0008] Hybrid synchronous control link: The angular velocity output by the power synchronous control link is integrated with the angular velocity output by the phase-locked synchronous control link through a hybrid system to achieve hybrid synchronous control;

[0009] The virtual excitation control link simulates the excitation dynamic characteristics of the synchronous generator through the electromagnetic equations in the third-order practical model of the synchronous generator;

[0010] The voltage phasor limiting link suppresses the fault current by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage;

[0011] The virtual impedance limiting link uses virtual impedance switching to increase the output impedance of the converter and limit the transient impact current component during the fault period.

[0012] Furthermore, the DC voltage control link obtains the deviation between the actual DC voltage value and the reference value, and controls the deviation through virtual frequency modulation to obtain the power reference value addition. The specific model of the DC voltage control link is:

[0013]

[0014] Where ΔP ref U is the additional amount of power reference value; DCref is the DC voltage reference value; U DC is the measured value of DC voltage; K pDC is the DC voltage control proportional coefficient; K iDC is the DC voltage control integral coefficient.

[0015] Furthermore, in the power synchronization control link, the sum of the power reference value addition and the active reference power is used as the converter virtual mechanical power, and the difference between the virtual mechanical power and the virtual electromagnetic power is obtained through the power synchronization control link to obtain the converter virtual speed, including:

[0016] Taking the sum of the power reference value addition and the active reference power as the virtual mechanical power of the converter;

[0017] The actual output active power of the converter is used as the virtual electromagnetic power;

[0018] The difference between the virtual mechanical power and the virtual electromagnetic power is passed through a power synchronization control link to obtain a virtual speed of the converter;

[0019] The control model of the power synchronization control link is specifically as follows:

[0020]

[0021] Among them, T j is the virtual inertia time constant; 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 the amplification link, which feeds back the steady-state frequency deviation, and D is the damping coefficient; the second part consists of the amplification link, the DC isolation link and the 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.

[0022] Furthermore, in the 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 unit and the grid. The specific model of the phase-locked synchronization control link is:

[0023]

[0024] 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 phase-locked loop integral control coefficient; U gq is the q-axis component of the grid-connected point voltage.

[0025] Furthermore, the hybrid synchronous control link integrates the angular velocity output by the power synchronous control link and the angular velocity output by the phase-locked synchronous control link through a hybrid system to achieve hybrid synchronous control. The model of the hybrid synchronous control link is specifically 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 The mixing coefficient is controlled for power synchronization.

[0028] Furthermore, the virtual excitation control link simulates the excitation dynamic characteristics of the synchronous generator through the electromagnetic equations in the third-order practical model of the synchronous generator, including:

[0029] The actual voltage signal of the virtual excitation voltage regulator is obtained by collecting the output of the converter and passing it through the differential adjustment link:

[0030]

[0031] 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, XC is the differential reactance;

[0032] 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:

[0033]

[0034] 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 ref 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 ; Among them, the electromagnetic equation in the third-order practical model of the synchronous generator is:

[0035]

[0036] 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 d is the synchronous reactance; x′ d is the d-axis transient reactance.

[0037] Furthermore, the voltage phasor limiting link suppresses the fault current by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage, including:

[0038] 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 the reference coordinate system to obtain the converter output current constraint:

[0039]

[0040] 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 max is the total current limit value;

[0041] According to the output current constraint of the converter, the virtual internal potential rounding condition can be obtained as follows:

[0042]

[0043] 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.

[0044] Furthermore, the virtual impedance limiting link uses virtual impedance switching to increase the output impedance of the converter and limit the transient impact current component during the fault period, including:

[0045] The virtual impedance control model is expressed as follows:

[0046]

[0047] Among them, U c * dqref The final value of the virtual internal potential dq axis component is generated, 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.

[0048] Furthermore, it also includes:

[0049] The output signal is controlled by the internal potential according to the virtual phase angle θ Perform Park inverse transform to obtain the voltage reference wave in the three-phase stationary coordinate system;

[0050] The voltage reference wave is used to generate a trigger pulse that meets the control requirements through a PWM generator to complete the overall output control.

[0051] The present invention also provides an active support control system for a stationary phase regulator based on virtual excitation control, comprising:

[0052] A DC voltage control module is configured to obtain a deviation between an actual DC voltage value and a reference value, and subject the deviation to virtual frequency modulation control to obtain an additional power reference value;

[0053] a power synchronization control module, configured to use the sum of the power reference value addition and the active reference power as the converter virtual mechanical power, and to obtain the converter virtual speed by passing the difference between the virtual mechanical power and the virtual electromagnetic power through a power synchronization control link;

[0054] Phase-locked synchronization control module, which is used for the phase-locked loop to collect the grid connection point voltage, lock and track the grid connection point phase, and realize the synchronous operation of the unit and the grid;

[0055] A hybrid synchronization control module is used to integrate the angular velocity output by the power synchronization control link and the angular velocity output by the phase-locked synchronization control link through a hybrid system to achieve hybrid synchronization control;

[0056] Virtual excitation control module, used to simulate the excitation dynamic characteristics of synchronous generators through electromagnetic equations in the third-order practical model of synchronous generators;

[0057] Voltage phasor limiting module, used to suppress fault current by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage;

[0058] The virtual impedance limiting module is used to increase the output impedance of the converter by using virtual impedance switching to limit the transient impact current component during the fault period.

[0059] The present invention proposes an active support control method and system for a stationary phase-shifting machine based on virtual excitation control. Virtual excitation control is used in a power electronic converter to generate a virtual internal potential amplitude, and a hybrid synchronization method of a phase-locked loop and power synchronization control is used to generate a virtual internal potential phase angle. At the same time, a direct voltage structure without a current inner loop is adopted, and fault current suppression is achieved by combining virtual impedance and voltage phasor limiting. This can provide inertia support and voltage support for the power grid, improve the short-circuit ratio of the grid connection point, enhance the stability of the system, and greatly improve the new energy transmission capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a control block diagram of a method for active support control of a stationary phase regulator based on virtual excitation control provided by an embodiment of the present invention;

[0061] Figure 2 The present invention provides a schematic structural diagram of an active support control system for a stationary phase regulator based on virtual excitation control. DETAILED DESCRIPTION

[0062] The following description sets forth numerous specific details to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific implementations disclosed below.

[0063] like Figure 1 As shown, the present invention provides an active support control method for a stationary phase regulator based on virtual excitation control, the control method comprising the following steps:

[0064] (1) The DC voltage control link obtains the deviation between the actual DC voltage value and the reference value, and controls the deviation through virtual frequency modulation to obtain the power reference value addition. This link is used to maintain the stability of the DC side voltage of the SVG and generate the power reference value compensation. After comparing the actual DC voltage value with the reference value, the dead zone control module is used. If the deviation exceeds the set dead zone, the output is the deviation exceeding the dead zone; otherwise, the output is 0. The output deviation is controlled by PI to obtain the power reference value addition. The specific model of the DC voltage control link is:

[0065]

[0066] Where ΔP ref U is the additional amount of power reference value; DCref is the DC voltage reference value; U DC is the measured value of DC voltage; K pDC is the DC voltage control proportional coefficient; K iDC is the DC voltage control integral coefficient.

[0067] (2) Power synchronization control link, taking the sum of the power reference value addition and the active reference power as the converter virtual mechanical power, and taking the difference between the virtual mechanical power and the virtual electromagnetic power through the power synchronization control link to obtain the converter virtual speed. Specifically, it includes:

[0068] By simulating the synchronous generator rotor motion equations and introducing inertia and damping components into the control, the converter's active support capability is enhanced. The sum of the additional reference power and active reference power obtained through the virtual frequency modulation control process is used as the converter's virtual mechanical power, while the converter's actual output active power is used as the virtual electromagnetic power. The difference between the two is passed through the power synchronization control process to obtain the converter's virtual speed.

[0069] The control model of the power synchronization control link is specifically as follows:

[0070]

[0071] Among them, T j is the virtual inertia time constant; 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 ref The damping feedback consists of two parts, the first part consists of the amplification link, which feeds back the steady-state frequency deviation, and D is the damping coefficient; the second part consists of the amplification link, the DC isolation link and the lead-lag link in series, which only feeds back the transient frequency deviation, K Dis 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.

[0072] (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 unit and the grid. The specific model of the phase-locked synchronization control link is:

[0073]

[0074] 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 phase-locked loop integral control coefficient; U gq is the q-axis component of the grid-connected point voltage.

[0075] (4) Hybrid synchronous control link: The angular velocity output by the power synchronous control link and the angular velocity output by the phase-locked synchronous control link are integrated through a hybrid system to achieve hybrid synchronous control. The model of the hybrid synchronous control link is as follows:

[0076]

[0077] 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.

[0078] (5) Virtual excitation control link, which simulates the excitation dynamic characteristics of the synchronous generator through the electromagnetic equations in the third-order practical model of the synchronous generator.

[0079] Simulate the characteristics of the synchronous generator excitation system and introduce the electromagnetic equations in the synchronous generator third-order practical model to accurately simulate the excitation dynamic characteristics:

[0080]

[0081] 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 d is the synchronous reactance; x′ d is the d-axis transient reactance.

[0082] First, the voltage and current at the output of the converter are collected, and after the difference adjustment link, the actual voltage signal of the virtual excitation voltage regulator is obtained:

[0083]

[0084] 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.

[0085] 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:

[0086]

[0087] 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 ref 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 .

[0088] (6) Voltage phasor limiting link, which suppresses fault current by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage.

[0089] 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 the reference coordinate system to obtain the converter output current constraint:

[0090]

[0091] 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 max is the total current limit value;

[0092] According to the output current constraint of the converter, the virtual internal potential rounding condition can be obtained as follows:

[0093]

[0094] 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 1 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 .

[0095] (7) Virtual impedance limiting link: virtual impedance switching is used to increase the output impedance of the converter and limit the transient impact current component during the fault period.

[0096] The virtual impedance control model is expressed as follows:

[0097]

[0098] in, The final value of the virtual internal potential dq axis component is generated, 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.

[0099] 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 a three-phase stationary coordinate system. This voltage reference wave is then used to generate trigger pulses that meet control requirements through a PWM generator, completing overall output control. Because overall control 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 control characteristics.

[0100] Based on the same inventive concept, the present invention also provides an active support control system for a stationary phase regulator based on virtual excitation control, such as Figure 2 As shown, including:

[0101] The DC voltage control module 210 is configured to obtain a deviation between an actual DC voltage value and a reference value, and subject the deviation to virtual frequency modulation control to obtain an additional power reference value;

[0102] The power synchronization control module 220 is configured to use the sum of the power reference value addition and the active reference power as the converter virtual mechanical power, and to obtain the converter virtual speed by passing the difference between the virtual mechanical power and the virtual electromagnetic power through a power synchronization control link;

[0103] Phase-locked synchronization control module 230, which is used for the phase-locked loop to collect the grid connection point voltage, lock and track the grid connection point phase, and realize the synchronous operation of the unit and the grid;

[0104] A hybrid synchronization control module 240 is used to integrate the angular velocity output by the power synchronization control link and the angular velocity output by the phase-locked synchronization control link through a hybrid system to achieve hybrid synchronization control;

[0105] A virtual excitation control module 250 is used to simulate the excitation dynamic characteristics of the synchronous generator through electromagnetic equations in a third-order practical model of the synchronous generator;

[0106] The voltage phasor limiting module 260 is used to suppress the fault current by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage;

[0107] The virtual impedance limiting module 270 is used to increase the output impedance of the converter by using a virtual impedance switching method to limit the transient impact current component during a fault.

[0108] The present invention proposes an active support control method and system for a stationary phase-shifting machine based on virtual excitation control. Virtual excitation control is used in a power electronic converter to generate a virtual internal potential amplitude, and a hybrid synchronization method of a phase-locked loop and power synchronization control is used to generate a virtual internal potential phase angle. At the same time, a direct voltage structure without a current inner loop is adopted, and fault current suppression is achieved by combining virtual impedance and voltage phasor limiting. This can provide inertia support and voltage support for the power grid, improve the short-circuit ratio of the grid connection point, enhance the stability of the system, and greatly improve the new energy transmission capacity.

[0109] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely 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 magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modifications or equivalents that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for active support control of a static phase condenser based on virtual excitation control, characterized in that: include: The DC voltage control link obtains the deviation between the actual DC voltage value and the reference value, and controls the deviation through virtual frequency modulation to obtain the power reference value addition; The power synchronization control link uses the sum of the power reference value addition and the active reference power as the converter virtual mechanical power, and the difference between the virtual mechanical power and the virtual electromagnetic power is passed through the power synchronization control link to obtain the converter virtual speed; 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 unit and the grid; Hybrid synchronous control link: The angular velocity output by the power synchronous control link is integrated with the angular velocity output by the phase-locked synchronous control link through a hybrid system to achieve hybrid synchronous control; The virtual excitation control link simulates the excitation dynamic characteristics of the synchronous generator through the electromagnetic equations in the third-order practical model of the synchronous generator; The voltage phasor limiting link suppresses the fault current by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage; The virtual impedance limiting link uses virtual impedance switching to increase the output impedance of the converter and limit the transient impact current component during the fault period.

2. The method according to claim 1, characterized in that The DC voltage control link obtains the deviation between the actual DC voltage value and the reference value, and applies virtual frequency modulation control to the deviation to obtain the power reference value addition. The DC voltage control link model is specifically as follows: Where ΔP ref U is the additional amount of power reference value; DCref is the DC voltage reference value; U DC is the measured value of DC voltage; K pDC is the DC voltage control proportional coefficient; K iDC is the DC voltage control integral coefficient.

3. The method according to claim 1, characterized in that The power synchronization control link uses the sum of the power reference value addition and the active reference power as the converter virtual mechanical power, and obtains the converter virtual speed by passing the difference between the virtual mechanical power and the virtual electromagnetic power through the power synchronization control link, including: Taking the sum of the power reference value addition and the active reference power as the virtual mechanical power of the converter; The actual output active power of the converter is used as the virtual electromagnetic power; The difference between the virtual mechanical power and the virtual electromagnetic power is passed through a power synchronization control link to obtain a virtual speed of the converter; The control model of the power synchronization control link is specifically as follows: Among them, T j is the virtual inertia time constant; 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 ref The damping feedback consists of two parts, the first part consists of the amplification link, which feeds back the steady-state frequency deviation, and D is the damping coefficient; the second part consists of the amplification link, the DC isolation link and the 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.

4. The method according to claim 1, wherein In the 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 unit and the grid. The specific model of the phase-locked synchronization control link is: 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 phase-locked loop integral control coefficient; U gq is the q-axis component of the grid-connected point voltage.

5. The method according to claim 1, wherein The hybrid synchronous control link integrates the angular velocity output by the power synchronous control link and the angular velocity output by the phase-locked synchronous control link through a hybrid system to achieve hybrid synchronous control. The specific model of the hybrid synchronous control link is: Where θ is the virtual phase angle of the internal potential; C PLL is the phase-locked synchronous control mixing coefficient; C PC The mixing coefficient is controlled for power synchronization.

6. The method according to claim 1, characterized in that The virtual excitation control link simulates the excitation dynamic characteristics of the synchronous generator through the electromagnetic equations in the third-order practical model of the synchronous generator, including: The actual voltage signal of the virtual excitation voltage regulator is obtained by collecting the output of the converter and passing it through the differential adjustment link: 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 is the differential reactance; 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: 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 ref 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 ; Among them, the electromagnetic equation in the third-order practical model of the synchronous generator is: 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 d is the synchronous reactance; x' d is the d-axis transient reactance.

7. The method according to claim 1, characterized in that The voltage phasor limiting link suppresses the fault current by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage, including: 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 the reference coordinate system to obtain the converter output current constraint: 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 max is the total current limit value; According to the output current constraint of the converter, the virtual internal potential rounding condition can be obtained as follows: 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.

8. The method according to claim 1, characterized in that The virtual impedance limiting link uses virtual impedance switching to increase the converter output impedance and limit the transient impact current component during the fault period, including: The virtual impedance control model is expressed 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.

9. The method according to claim 1 or 8, characterized in that Also includes: The output signal is controlled by the internal potential according to the virtual phase angle θ Perform Park inverse transform to obtain the voltage reference wave in the three-phase stationary coordinate system; The voltage reference wave is used to generate a trigger pulse that meets the control requirements through a PWM generator to complete the overall output control.

10. An active support control system for a stationary phase condenser based on virtual excitation control, characterized in that: include: A DC voltage control module is configured to obtain a deviation between an actual DC voltage value and a reference value, and subject the deviation to virtual frequency modulation control to obtain an additional power reference value; a power synchronization control module, configured to use the sum of the power reference value addition and the active reference power as the converter virtual mechanical power, and to obtain the converter virtual speed by passing the difference between the virtual mechanical power and the virtual electromagnetic power through a power synchronization control link; Phase-locked synchronization control module, which is used for the phase-locked loop to collect the grid connection point voltage, lock and track the grid connection point phase, and realize the synchronous operation of the unit and the grid; A hybrid synchronization control module is used to integrate the angular velocity output by the power synchronization control link and the angular velocity output by the phase-locked synchronization control link through a hybrid system to achieve hybrid synchronization control; Virtual excitation control module, used to simulate the excitation dynamic characteristics of synchronous generators through electromagnetic equations in the third-order practical model of synchronous generators; Voltage phasor limiting module, used to suppress fault current by limiting the voltage amplitude and phase difference between the virtual internal potential and the grid connection point voltage; The virtual impedance limiting module is used to increase the output impedance of the converter by using virtual impedance switching to limit the transient impact current component during the fault period.

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