WO2023125428A1 - 变流器控制系统及方法 - Google Patents

变流器控制系统及方法 Download PDF

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Publication number
WO2023125428A1
WO2023125428A1 PCT/CN2022/141977 CN2022141977W WO2023125428A1 WO 2023125428 A1 WO2023125428 A1 WO 2023125428A1 CN 2022141977 W CN2022141977 W CN 2022141977W WO 2023125428 A1 WO2023125428 A1 WO 2023125428A1
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WIPO (PCT)
Prior art keywords
vector
converter
voltage
dqpn
voltage reference
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PCT/CN2022/141977
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English (en)
French (fr)
Inventor
汪楠楠
卢宇
董云龙
田杰
詹长江
李海英
李钢
王仙荣
林艺哲
李建春
Original Assignee
南京南瑞继保电气有限公司
南京南瑞继保工程技术有限公司
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Priority to EP22914682.4A priority Critical patent/EP4372949A1/en
Publication of WO2023125428A1 publication Critical patent/WO2023125428A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/66—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal
    • H02M7/68—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters
    • H02M7/72—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/79—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/797—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Definitions

  • the present application relates to the field of power electronics, in particular, to a converter control system and method.
  • non-synchronous power sources such as new energy in the new power system in the future will account for a very high proportion in the power grid.
  • my country's power system cannot support the access of large-scale new energy power sources.
  • the main reason is that with the increase in the penetration rate of new energy power generation, the characteristics of low inertia and no damping of power electronic converters will affect the stable operation of the system. Negative impacts will bring challenges to the stable operation of the power grid.
  • the new power system with new energy power as the main body in the future with the large-scale access of more and more new energy sources with "no" moment of inertia, it will bring stability in terms of power angle, voltage, frequency, and broadband resonance. question.
  • Power electronic converters have the characteristics of flexible control, but in weak systems with large-scale new energy sources, system support requirements are put forward for power electronic converters. In order to make the power grid have the supporting capacity, it is necessary to avoid the use of phase-locked loops and make the power electronic converter have the characteristics of a voltage source.
  • the typical representative is the use of amplitude-phase control (indirect current control) or power synchronous control (including virtual synchronous machine control, etc.) Voltage source converter.
  • CN106786733B and CN106356884B propose different forms of control systems for virtual synchronous generators, but they all use current inner loops to realize converter control.
  • the virtual impedance link in CN107528495B introduces direct current feedback to improve the impact resistance of the converter.
  • the direct current feedback of the existing virtual synchronous generator control method will feed into harmonic components, causing the converter to present negative resistance in some frequency bands, increasing the risk of oscillation; but the current closed loop is not used Control can not solve the problem of limited overcurrent capacity of the converter.
  • the purpose of this application is to propose a converter control system and method that does not use current closed-loop control to maintain the characteristics of the voltage source under steady state and small disturbance conditions, so as to reduce the risk of oscillation, and simulate and The consistent grid support characteristics of synchronous generators realize the active adjustment of converter impedance and improve grid-connected adaptability.
  • a converter control system for controlling a converter to simulate a synchronous generator, the converter control system includes a power synchronous control unit, an AC voltage reference vector calculation unit, and an AC voltage command Produces cells where:
  • the power synchronous control unit is used to simulate the governor and the mechanical inertia link of the synchronous generator to generate a reference phase
  • the AC voltage reference vector calculation unit generates an AC voltage reference vector according to the internal potential vector and the collected AC voltage vector;
  • the AC voltage command generating unit generates a three-phase AC voltage control command according to the AC voltage reference vector and the reference phase;
  • the internal potential vector is determined from simulated synchronous generator characteristics.
  • the AC voltage reference vector calculation unit is configured to:
  • the proportional coefficient K rv is determined according to the virtual impedance X v of the converter and the actual impedance X r of the converter:
  • the internal potential vector E dqpn , the AC voltage vector Us dqpn , and the AC voltage reference vector Uc dqpn are all 4-dimensional vectors, corresponding to the dq axis components on the positive and negative sequences;
  • x dqpn [x dp ,x qp ,x dn ,x qn ] T
  • x dp is the positive sequence d-axis component
  • x qp is the positive sequence q-axis component
  • x dn is the negative sequence d axis component
  • x qn is the negative sequence d axis component.
  • the AC voltage reference vector calculation unit is configured to:
  • the proportional coefficient K rv is determined according to the virtual impedance X v of the converter and the actual impedance X r of the converter:
  • the internal potential vector E ⁇ pn , the AC voltage vector Us ⁇ pn , and the AC voltage reference vector Uc ⁇ pn are all 4-dimensional vectors, corresponding to the ⁇ axis components on the positive and negative sequences;
  • the virtual impedance X v is used to simulate the impedance of the generator:
  • the value range is 0 to 1 times the rated impedance during steady state operation
  • it also includes an AC voltage control unit AVR, which is used to adjust the AC voltage at the grid-connected point of the converter, and output the positive sequence d-axis component E dp of the internal potential; wherein, the positive sequence q-axis component E qp of the internal potential, The negative sequence d-axis component E dn and the negative sequence q-axis component E qn are 0.
  • AVR AC voltage control unit
  • a control error compensation unit is further included, the control error compensation unit is configured to:
  • the control error compensation amount is added to the AC voltage reference vector Uc dqpn as the converter AC voltage reference vector.
  • a fault current limiting unit is also included, wherein:
  • the fault current limiting unit is put into operation during transient overcurrent, and according to the deviation between the AC current limit command and the actual converter AC current, a fault current limiting control value is generated, which is superimposed on the AC voltage reference vector Uc dqpn as the
  • the AC voltage reference vector of the converter controls the AC current amplitude at the maximum AC current amplitude limit Imax, and the direction is 90 degrees behind the voltage drop of the virtual impedance Xv .
  • the fault current limiting unit is configured to be turned on for a short time when a transient overcurrent occurs, and the time for the short time to be turned on is 1ms-1s.
  • control system is used for at least one of a direct current transmission converter, an energy storage converter, a micro-grid converter, a photovoltaic inverter or a wind power converter.
  • a converter control method for controlling a converter to simulate a synchronous generator, including the converter control system as described in any one of the foregoing:
  • the power synchronous control unit simulates the speed governor and the mechanical inertia link of the generator to generate a reference phase
  • the AC voltage reference vector calculation unit generates an AC voltage reference vector according to the internal potential vector and the collected AC voltage vector;
  • the AC voltage command generating unit generates a three-phase AC voltage control command according to the AC voltage reference value vector and the reference phase;
  • the internal potential vector is determined from simulated synchronous generator characteristics.
  • the AC voltage reference vector calculation unit is configured to:
  • the proportional coefficient K rv is determined according to the virtual impedance X v of the converter and the actual impedance X r of the converter:
  • the virtual impedance X v is used to simulate the impedance of the generator, and the value ranges from 0 to 1 times the rated impedance during steady-state operation; the virtual impedance X v is increased during transient operation to keep the internal potential stable.
  • the AC voltage reference vector calculation unit is configured to:
  • the proportional coefficient K rv is determined according to the virtual impedance X v of the converter and the actual impedance X r of the converter:
  • the internal potential vector E ⁇ pn , the AC voltage vector Us ⁇ pn , and the AC voltage reference vector Uc ⁇ pn are all 4-dimensional vectors, corresponding to the ⁇ axis components on the positive and negative sequences;
  • the AC voltage control unit AVR realizes the AC voltage regulation of the grid-connected point of the converter, and outputs the positive-sequence d-axis component E dp of the internal potential; among them, the positive-sequence q-axis component E qp of the internal potential, the negative-sequence d-axis component E dn and the negative-sequence
  • the q-axis component E qn is 0.
  • a control error compensation unit is further included, the control error compensation unit is configured to:
  • the control error compensation unit generates a control error compensation amount according to the deviation between the AC voltage reference vector Uc dqpn and the actual converter AC voltage vector Uc dppn_m ;
  • the control error compensation amount is added to the AC voltage reference vector Uc dqpn to be used as the AC voltage reference vector of the converter.
  • the fault current limiting unit is switched on during transient overcurrent, and according to the deviation between the AC current limit command and the actual converter AC current, a fault current limit control value is generated, which is superimposed with the AC voltage reference vector Uc dqpn as the converter current
  • the AC voltage reference vector of the device controls the AC current amplitude at the maximum AC current amplitude limit Imax, and the direction is 90 degrees behind the voltage drop of the virtual impedance Xv .
  • the fault current limiting unit is configured to be turned on for a short time when a transient overcurrent occurs, and the time for the short time to be turned on is 1ms-1s.
  • a program product including the converter control system as described in any one of the foregoing.
  • an electronic device including the aforementioned program product.
  • a converter control system and method provided by this application does not use current closed-loop control under steady state and small disturbance conditions, which can effectively reduce the risk of oscillation;
  • a converter control system and method provided by this application can simulate the grid support characteristics consistent with the synchronous generator
  • the converter control system and method provided by this application can realize the active adjustment of the virtual impedance of the converter without using the current closed-loop control, improve the grid-connected adaptability, and reduce the fault in the event of a fault current;
  • a converter control system and method provided by this application does not need to configure a fault current limiting unit when the converter’s overcurrent capacity is satisfied; when the converter’s overcurrent capacity is less than the fault current, after the fault Enter the transient state operation, put into the fault current limiting unit, avoid the overcurrent tripping of the converter, and be able to adapt to the converters with different capabilities.
  • Figure 1a shows a block diagram of a converter control system in an example embodiment of the present application
  • Fig. 1b shows a block diagram of a method for implementing a converter control system in an example embodiment of the present application
  • Fig. 2 shows a positive sequence vector diagram of a converter control system implementing converter control in an example embodiment of the present application
  • Fig. 3a shows a schematic diagram of an AC voltage control unit AVR in an exemplary embodiment of the present application
  • FIG. 3b shows a block diagram of an implementation method of an AC voltage control unit AVR in an exemplary embodiment of the present application
  • Fig. 4 shows another embodiment of a block diagram of a converter control system in the example of the present application
  • Fig. 5 shows a block diagram of a control error compensation unit in an example embodiment of the present application
  • FIG. 6 shows a block diagram of a fault current limiting unit of an exemplary embodiment of the present application
  • FIG. 7 shows a flow chart of a converter control method in an example embodiment of the present application.
  • Fig. 8a and Fig. 8b show the fault ride-through effect diagrams of the converter control method according to the exemplary embodiment of the present application.
  • Example embodiments will now be described more fully with reference to the accompanying drawings.
  • Example embodiments may, however, be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art.
  • the same reference numerals denote the same or similar parts in the drawings, and thus their repeated descriptions will be omitted.
  • Fig. 1a shows a block diagram of a converter control system according to an example embodiment of the present application.
  • the converter control system is used to control the converter analog synchronous generator, including: power synchronization control unit 1, AC voltage reference vector calculation unit 2 and AC voltage command generation unit 3.
  • the power synchronous control unit 1 is used to simulate the governor of the generator and the mechanical inertia link to generate the reference phase ⁇ ;
  • the AC voltage reference vector calculation unit 2 is used to calculate the AC voltage reference vector Uc dqpn of the converter;
  • the AC voltage command generation unit 3 A three-phase AC voltage control command Uc abc is generated according to the AC voltage reference vector Uc dqpn and the reference phase ⁇ .
  • Fig. 1b shows a block diagram of a method for implementing a converter control system in an example embodiment of the present application.
  • Fig. 1b is a detailed implementation method of a converter control system provided by the present invention.
  • the power synchronous control unit 1 adopts the generator swing equation shown in formula (1) to realize the simulation of the governor and the mechanical inertia link of the generator.
  • ⁇ is the angular velocity
  • H is the inertial time constant
  • Pre ref is the active command
  • P s is the electromagnetic active power
  • K f is the proportional coefficient of the governor
  • ⁇ is the angular velocity deviation.
  • the AC voltage reference vector calculation unit 2 calculates the AC voltage reference vector Uc dqpn of the converter according to the proportional coefficient K rv , the internal potential vector E dqpn and the collected AC voltage vector Us dqpn :
  • the proportional coefficient K rv is determined according to the virtual impedance X v of the converter and the actual impedance X r of the converter:
  • the E dqpn , Us dqpn , and Uc dqpn are all 4-dimensional vectors, corresponding to the dq axis components on the positive and negative sequences.
  • x dqpn [x dp , x qp , x dn , x qn ] T , where x dp is the positive sequence d-axis component, where x qp is the positive sequence q-axis component, where x dn is the negative sequence d-axis component, and x qn is the negative sequence d-axis component.
  • the positive and negative sequence components in the AC voltage reference vector Uc dqpn of the AC voltage command generation unit 3 obtain the synthesized three-phase AC voltage control command vector Uc abc according to the reference phase ⁇ :
  • the three-phase AC voltage control command can be obtained as:
  • Fig. 2 shows a positive sequence vector diagram of a converter control system implementing converter control according to an example embodiment of the present application.
  • the above vector is relative to the reference phase ⁇ .
  • Is n Is dn +jIs qn is the negative sequence vector of the alternating current
  • the above vector is relative to the reference phase ⁇ .
  • Formula (2) can be obtained from formulas (9) and (10). By using the formula (2) to calculate the reference AC voltage reference vector Uc dqpn , the AC current signal is avoided, so the risk of oscillation can be effectively reduced, and since the vector diagram is consistent with the synchronous generator, the grid support characteristics consistent with the synchronous generator can be simulated .
  • Different generator impedances can be simulated by adjusting the virtual impedance Xv .
  • the virtual impedance X v ranges from 0 to 1 times the rated impedance, and it is better to select the virtual impedance X v to be equal to the actual impedance X r ; when a large disturbance such as a fault causes overcurrent, it enters transient operation State, by increasing the virtual impedance X v to keep the internal potential of the converter stable, that is, when Us p or Us n changes greatly, by increasing the virtual impedance X v , the vector relationship shown in Figure 2 or the equivalent The negative-sequence vector relation satisfies the simulation of different generator impedances.
  • Fig. 3a shows a schematic diagram of an AC voltage control unit AVR according to an exemplary embodiment of the present application.
  • FIG. 3a a schematic diagram of an AC voltage control unit AVR is provided, which is used to adjust the AC voltage at the grid-connected point of the converter.
  • the deviation between the AC voltage command value U ref and the actual value U of the AC voltage is calculated by the AVR unit 31
  • the positive sequence d-axis component E dp of the internal potential According to the characteristics of the generator, the positive-sequence q-axis component E dp , the negative-sequence d-axis component E dn , and the negative-sequence q-axis component E qn of the internal potential are all zero.
  • Fig. 3b shows a block diagram of an implementation method of an AC voltage control unit AVR according to an example embodiment of the present application.
  • Fig. 3b is a detailed embodiment of an AVR unit 31 provided by the present application.
  • the deviation between the AC voltage command value U ref and the actual value U of the AC voltage is multiplied by the voltage droop coefficient K U to obtain the reactive power regulation ⁇ Q.
  • the AC voltage regulation ⁇ E is obtained through the PI controller, and the AC voltage regulation ⁇ E is added to the rated AC voltage E 0 to obtain the positive sequence d-axis component E dp of the internal potential.
  • Fig. 4 shows another embodiment of a block diagram of a converter control system in the example of the present application.
  • the converter control system also includes a control error compensation unit 4 and a fault current limiting unit 5 .
  • a control error compensation unit 4 can be added to reduce the deviation.
  • the control error compensation amount ⁇ Uc dqpn_com is generated, which is added to the AC voltage reference vector Uc dqpn as the converter AC voltage reference vector.
  • a fault current limiting unit 5 can be added, which is switched on during transient overcurrent, and a fault limiting unit 5 is generated according to the deviation between the AC current limiting command and the actual converter AC current.
  • the current control value ⁇ Uc dqpn_ilim is superimposed with the original converter AC voltage reference vector and used as the converter AC voltage reference vector to realize the AC current amplitude near the maximum AC current amplitude limit I max and avoid the converter overcurrent trip ;
  • the magnitude of the AC voltage limit command is I max , and the direction is 90 degrees behind the voltage drop on the virtual impedance.
  • Fig. 5 shows a block diagram of a control error compensation unit in an example embodiment of the present application.
  • the block diagram 4 of the control error compensation unit is applied to the control error compensation of the modular multilevel converter.
  • Negative sequence dq axis vector Vn dqpn according to the collected three-phase upper bridge arm voltage through positive and negative sequence decomposition and park transformation to obtain the upper bridge arm positive and negative sequence dq axis vector Vp dqpn , subtract Vn dqpn from Vp dqpn and multiply by
  • the actual converter AC voltage vector Uc dqpn_m is obtained by using 0.5 .
  • the control error compensation amount ⁇ Uc dqpn_com is obtained after the first-order inertial link 41.
  • the control error compensation amount and the AC voltage reference vector Uc dqpn is added together as the AC voltage reference vector of the converter to reduce the error between the AC voltage reference vector Uc dqpn and the actual converter AC voltage vector Uc dqpn_m .
  • Fig. 6 shows a block diagram of a fault current limiting unit in an example embodiment of the present application.
  • FIG. 6 it is a detailed embodiment of the fault current limiting unit 5 . Since the voltage drop on the virtual impedance is Us dqpn -E dqpn , the amplitude of the AC current limiting command Isref dqpn is I max , lagging behind the voltage drop on the virtual impedance by 90 degrees, therefore:
  • J is the lag 90 operator of the four-dimensional vector, and satisfies:
  • the fault current limit control value ⁇ Uc dqpn_ilim is obtained, which is superimposed with the original converter AC voltage reference vector and used as the converter AC voltage reference vector to realize that the AC current amplitude is near the maximum AC current amplitude limit I max .
  • the fault current limiting unit 5 can be configured to be turned on only for a short time when a transient overcurrent occurs, and the time for the short time to be turned on is 1 ms to 1 s.
  • Fig. 7 shows a flow chart of a converter control method in an example embodiment of the present application.
  • Step 701 Generate a reference phase ⁇ by a power synchronization control unit.
  • the reference phase ⁇ is generated, and the speed governor and mechanical inertia link of the simulated generator are realized.
  • Step 702 Calculate the AC voltage reference vector Uc dqpn of the converter by the AC voltage control unit.
  • the AC voltage reference vector Uc dqpn of the converter is calculated from the proportional coefficient K rv , the internal potential E dqpn and the collected AC voltage vector Us dqpn :
  • Step 703 Generate a three-phase AC voltage control command by the AC voltage command generation unit.
  • the three-phase AC voltage control command is obtained according to formula (5).
  • Fig. 8a and Fig. 8b show the fault ride-through effect diagrams of the converter control method according to the exemplary embodiment of the present application.
  • Figure 8a shows the fault ride-through effect of the control system shown in Figure 1a.
  • the current closed-loop control is not used in the whole process of steady state and fault transient state.
  • the initial current is relatively large.
  • the AC current is at the maximum Around 1.2 times the rated current of the AC current amplitude limit. Therefore, the characteristics of the generator can be completely simulated without the introduction of current closed-loop control, but it needs to have a certain ability to overload the converter for a short time.
  • Fig. 8b shows the fault ride-through effect of the control system shown in Fig. 4, and the control error compensation unit is added; during the fault transient period, the fault current limiting unit is temporarily put into use. After a fault occurs, the AC current can be quickly reduced to around 1.2 times the rated current of the maximum AC current amplitude limit. Since the current command of the fault current limiting unit is consistent with the current of the generator, the characteristics of the generator can still be simulated well.
  • the dq axis components are used to represent the vector, and the ⁇ component can also be used to represent the vector, and the corresponding relationship is as follows:

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  • Control Of Eletrric Generators (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

本申请提出一种变流器控制系统及方法，用于控制变流器模拟同步发电机。包括功率同步控制单元、交流电压参考向量计算单元和交流电压指令产生单元。所述功率同步控制单元，用于模拟同步发电机的调速器和机械惯性环节，产生参考相位；所述交流电压参考向量计算单元，采集内电势向量和交流电压向量，产生交流电压参考向量；所述交流电压指令产生单元，根据所述交流电压参考向量和所述参考相位产生三相交流电压控制指令。本申请提供的变流器控制系统和方法在稳态和小扰动情况下不采用电流闭环控制能够减少振荡风险，在稳态和暂态下均模拟与同步发电机一致电网支撑特性，且能够实现变流器阻抗的主动调节，提高并网适应性。

Description

变流器控制系统及方法 技术领域
本申请涉及电力电子计术领域，具体而言，涉及一种变流器控制系统及方法。
背景技术
为了实现双碳目标，未来新型电力系统中新能源等非同步机电源将会在电网中占非常高的比重。但是目前我国的电力系统尚不能支撑大规模新能源电源的接入，主要原因是随着新能源发电渗透率的提高，电力电子变流器的低惯性、无阻尼等特点将对系统的稳定运行产生负面影响，给电网的稳定运行带来挑战。在未来新能源电源为主体的新型电力系统中，随着越来越多的“无”转动惯量的新能源大规模接入，将带来功角、电压、频率、宽频谐振等稳定性方面的问题。
电力电子变流器具有控制灵活的特点，但是在含大规模新能源电源弱系统中，对电力电子变流器提出系统支撑的要求。为了使电网具备支撑能力，需要避免采用锁相环并使电力电子变流器具有电压源特性，典型代表是采用幅相控制(间接电流控制)或功率同步控制(包括虚拟同步机控制等)的电压源变流器。
CN106786733B和CN106356884B提出不同形式的虚拟同步发电机的控制系统，但均采用电流内环实现变流器控制。CN107528495B中虚拟阻抗环节引入直接电流反馈以提高变流器的抗冲击能力。但是由于控制延时的存在，现有的虚拟同步发电机控制方法的直接电流反馈会馈入谐波分量，使变流器在部分频段呈现负阻，增加出现振荡的风险；但是不采用电流闭环控制又无法解决变流器过流能力有限的问题。
在所述背景技术部分公开的上述信息仅用于加强对本申请的背景的理解，因此它可以包括不构成对本领域普通技术人员已知的现有技术的信息。
发明内容
本申请旨在提出一种在稳态和小扰动情况下不采用电流闭环控制的保持电压源特性的变流器控制系统及方法，实现减少振荡的风险，在稳态和暂态下均模拟与同步发电机一致的电网支撑特性，实现变流器阻抗的主动调节，提高并网适应性。
根据本申请的一方面，提出一种变流器控制系统，用于控制变流器模拟同步发电机，所述变流器控制系统包括功率同步控制单元、交流电压参考向量计算单元和交流电压指令产生单元，其中：
所述功率同步控制单元，用于模拟同步发电机的调速器和机械惯性环节，产生参考相位；
所述交流电压参考向量计算单元，根据内电势向量和采集的交流电压向量，产生交流电压参考向量；
所述交流电压指令产生单元，根据所述交流电压参考向量和所述参考相位产生三相交流电压控制指令；
所述内电势向量根据模拟的同步发电机特性确定。
根据一些实施例，所述交流电压参考向量计算单元配置为：
根据比例系数K rv,所述内电势向量E dqpn以及所述交流电压向量Us dqpn，计算所述交流电压参考向量Uc dqpn：
Uc dqpn＝E dqpn+K rv(Us dqpn-E dqpn)；
所述比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
Figure PCTCN2022141977-appb-000001
所述内电势向量E dqpn、交流电压向量Us dqpn、交流电压参考向量Uc dqpn均为4维向量，对应正负序上的dq轴分量；
任一向量x dqpn定义为：x dqpn＝[x dp,x qp,x dn,x qn] T，x dp为正序d轴分量，x qp为正序q轴分量，x dn为负序d轴分量，x qn为负序d轴分量。
根据一些实施例，所述交流电压参考向量计算单元配置为：
根据比例系数K rv,所述内电势向量E αβpn以及所述交流电压向量 Us αβpn，计算所述交流电压参考向量Uc αβpn：
Uc αβpn＝E αβpn+K rv(Us αβpn-E αβpn)；
所述比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
Figure PCTCN2022141977-appb-000002
所述内电势向量E αβpn、交流电压向量Us αβpn、交流电压参考向量Uc αβpn均为4维向量，对应正负序上的αβ轴分量；
任一向量x αβpn定义为：x αβpn＝[x αp，x βp，x αn，x βn] T，x αp为正序α轴分量，x βp为正序β轴分量，x αn为负序α轴分量，x βn为负序β轴分量。
根据一些实施例，所述虚拟阻抗X v用于模拟发电机的阻抗：
稳态运行时取值范围为0至1倍额定阻抗；
暂态运行时增大虚拟阻抗X v，使内电势保持稳定。
根据一些实施例，还包括交流电压控制单元AVR,用于实现变流器并网点交流电压调节，输出内电势的正序d轴分量E dp；其中，内电势的正序q轴分量E qp，负序d轴分量E dn和负序q轴分量E qn为0。
根据一些实施例，还包括控制误差补偿单元，所述控制误差补偿单元配置为：
根据所述交流电压参考向量Uc dqpn与实际变流器交流电压向量Uc dppn_m的偏差，产生控制误差补偿量；
将所述控制误差补偿量与所述交流电压参考向量Uc dqpn相加，作为变流器交流电压参考向量。
根据一些实施例，还包括故障限流单元，其中：
所述故障限流单元在暂态过流时投入，根据交流电流限制指令与实际变流器交流电流的偏差，产生故障限流控制量，与所述交流电压参考向量Uc dqpn叠加后作为所述变流器交流电压参考向量，控制交流电流幅值在最大交流电流幅值限值Imax，方向为滞后于所述虚拟阻抗X v的电压降90度。
根据一些实施例，所述故障限流单元配置为在暂态过流时短时投入，所述短时投入的时间为1ms-1s。
根据一些实施例，所述控制系统用于直流输电变流器、储能变流器、微网变流器、光伏逆变器或风电变流器的至少一种。
根据本申请的另一方面，提出一种变流器控制方法，用于控制变流器模拟同步发电机，包括如前文中任一项所述的变流器控制系统：
所述功率同步控制单元模拟发电机的调速器和机械惯性环节，产生参考相位；
所述交流电压参考向量计算单元，根据内电势向量和采集的交流电压向量，根据发产生交流电压参考向量；
所述交流电压指令产生单元，根据所述交流电压参考值向量和所述参考相位产生三相交流电压控制指令；
所述内电势向量根据模拟的同步发电机特性确定。
根据一些实施例，所述交流电压参考向量计算单元配置为：
根据比例系数K rv,内电势E dqpn以及交流电压向量Us dqpn，计算交流电压参考值向量Uc dqpn：
Uc dqpn＝E dqpn+K rv(Us dqpn-E dqpn)
所述比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
Figure PCTCN2022141977-appb-000003
所述虚拟阻抗X v用于模拟发电机的阻抗，稳态运行时取值范围为0至1倍额定阻抗；暂态运行时增大虚拟阻抗X v，使内电势保持稳定。
根据一些实施例，所述交流电压参考向量计算单元配置为：
根据比例系数K rv,所述内电势向量E αβpn以及所述交流电压向量Us αβpn，计算所述交流电压参考向量Uc αβpn：
Uc αβpn＝E αβpn+K rv(Us αβpn-E αβpn)；
所述比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
Figure PCTCN2022141977-appb-000004
所述内电势向量E αβpn、交流电压向量Us αβpn、交流电压参考向量 Uc αβpn均为4维向量，对应正负序上的αβ轴分量；
任一向量x αβpn定义为：x αβpn＝[x αp，x βp，x αn，x βn] T，x αp为正序α轴分量，x βp为正序β轴分量，x αn为负序α轴分量，x βn为负序β轴分量。
根据一些实施例，还包括：
交流电压控制单元AVR实现变流器并网点交流电压调节，输出内电势的正序d轴分量E dp；其中，内电势的正序q轴分量E qp，负序d轴分量E dn和负序q轴分量E qn为0。
根据一些实施例，还包括控制误差补偿单元，所述控制误差补偿单元配置为：
控制误差补偿单元根据所述交流电压参考向量Uc dqpn与实际变流器交流电压向量Uc dppn_m的偏差，产生控制误差补偿量；
所述控制误差补偿量与所述交流电压参考向量Uc dqpn相加，作为变流器交流电压参考向量。
根据一些实施例，还包括：
故障限流单元在暂态过流时投入，根据交流电流限制指令与实际变流器交流电流的偏差，产生故障限流控制量，与所述交流电压参考向量Uc dqpn叠加后作为所述变流器交流电压参考向量，控制交流电流幅值在最大交流电流幅值限值Imax，方向为滞后于所述虚拟阻抗X v的电压降90度。
根据一些实施例，所述故障限流单元配置为在暂态过流时短时投入，所述短时投入的时间为1ms-1s。
根据本申请的另一方面，提出一种程序产品，包括如前文中任一项所述的变流器控制系统。
根据本申请的另一方面，提出一种电子设备，包括如前文所述的程序产品。
根据本申请的一些实施例的技术方案可具有以下有益效果中的一个或多个：
1、本申请提供的一种变流器控制系统及方法，在稳态和小扰动情况 下不采用电流闭环控制，能够有效减少振荡的风险；
2、本申请提供的一种变流器控制系统及方法，能够模拟与同步发电机一致电网支撑特性；
3、本申请提供的一种变流器控制系统及方法，在不采用电流闭环控制的情况下，能够实现变流器虚拟阻抗的主动调节，提高并网适应性，在故障时可减小故障电流；
4、本申请提供的一种变流器控制系统及方法，在变流器过流能力满足时，不需要配置故障限流单元；在变流器过流能力小于故障电流时，故障过流后进入暂态运行，投入故障限流单元，避免变流器过流跳闸，能够适应不同能力的变流器。
应当理解的是，以上的一般描述和后文的细节描述仅是示例性的，并不能限制本申请。
附图说明
通过参照附图详细描述其示例实施例，本申请的上述和其它目标、特征及优点将变得更加显而易见。下面描述的附图仅仅是本申请的一些实施例，而不是对本申请的限制。
图1a示出本申请示例实施例的一种变流器控制系统框图；
图1b示出本申请示例实施例的一种变流器控制系统实现方法框图；
图2示出本申请示例实施例的一种变流器控制系统实现变流器控制的正序向量图；
图3a示出本申请示例实施例的一种交流电压控制单元AVR示意图；
图3b示出本申请示例实施例的一种交流电压控制单元AVR实现方法框图；
图4示出本申请示例的一种变流器控制系统框图的又一实施例；
图5示出本申请示例实施例的一种控制误差补偿单元框图；
图6示出本申请示例实施例的一种故障限流单元框图；
图7示出本申请示例实施例的一种变流器控制方法流程图；
图8a、图8b示出本申请示例实施例的变流器控制方法故障穿越效果图。
具体实施方式
现在将参考附图更全面地描述示例实施例。然而，示例实施例能够以多种形式实施，且不应被理解为限于在此阐述的实施例；相反，提供这些实施例使得本申请将全面和完整，并将示例实施例的构思全面地传达给本领域的技术人员。在图中相同的附图标记表示相同或类似的部分，因而将省略对它们的重复描述。
所描述的特征、结构或特性可以以任何合适的方式结合在一个或更多实施例中。在下面的描述中，提供许多具体细节从而给出对本公开的实施例的充分理解。然而，本领域技术人员将意识到，可以实践本公开的技术方案而没有这些特定细节中的一个或更多，或者可以采用其它的方式、组元、材料、装置等。在这些情况下，将不详细示出或描述公知结构、方法、装置、实现、材料或者操作。
附图中所示的流程图仅是示例性说明，不是必须包括所有的内容和操作/步骤，也不是必须按所描述的顺序执行。例如，有的操作/步骤还可以分解，而有的操作/步骤可以合并或部分合并，因此实际执行的顺序有可能根据实际情况改变。
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别不同对象，而不是用于描述特定顺序。此外，术语“包括”和“具有”以及它们任何变形，意图在于覆盖不排他的包含。例如包含了一系列步骤或单元的过程、方法、系统、产品或设备没有限定于已列出的步骤或单元，而是可选地还包括没有列出的步骤或单元，或可选地还包括对于这些过程、方法、产品或设备固有的其他步骤或单元。
本领域技术人员可以理解，附图只是示例实施例的示意图，附图中的模块或流程并不一定是实施本申请所必须的，因此不能用于限制本申请的保护范围。
下面描述本申请的装置实施例，其可以用于执行本申请方法实施例。对于本申请装置实施例中未披露的细节，可参照本申请方法实施例。
图1a示出本申请示例实施例的一种变流器控制系统框图。
如图1a所示，变流器控制系统用于控制变流器模拟同步发电机，包括：功率同步控制单元1、交流电压参考向量计算单元2和交流电压指令产生单元3。功率同步控制单元1用于模拟发电机的调速器和机械惯性环节产生参考相位θ；交流电压参考向量计算单元2用于计算变流器的交流电压参考向量Uc dqpn；交流电压指令产生单元3根据交流电压参考向量Uc dqpn和参考相位θ产生三相交流电压控制指令Uc abc。
图1b示出本申请示例实施例的一种变流器控制系统实现方法框图。
图1b为本发明提供的一种变流器控制系统详细实现方法。功率同步控制单元1采用如式(1)所示的发电机摇摆方程，实现发电机的调速器和机械惯性环节的模拟。其中ω为角速度，H为惯性时间常数，P ref为有功指令，P s为电磁有功功率，K f为调速器的比例系数，Δω为角速度偏差量。
Figure PCTCN2022141977-appb-000005
交流电压参考向量计算单元2根据比例系数K rv,内电势向量E dqpn以及采集的交流电压向量Us dqpn，计算变流器的交流电压参考向量Uc dqpn：
Uc dqpn＝E dqpn+K rv(Us dqpn-E dqpn)       (2)
其中比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
Figure PCTCN2022141977-appb-000006
所述E dqpn、Us dqpn、Uc dqpn均为4维向量，对应正负序上的dq轴分量，对于任一向量x有如下定义，x dqpn＝[x dp,x qp,x dn,x qn] T，其中x dp为正序d轴分量，其中x qp为正序q轴分量，其中x dn为负序d轴分量，其中x qn为负序d轴分量。
交流电压指令产生单元3交流电压参考向量Uc dqpn中正负序分量根据参考相位θ得到合成的三相交流电压控制指令向量Uc abc：
Uc abc＝(Uc dp+jUc qp)e jθ+(Uc dn+jUc qn)e -jθ       (4)
根据式(4)可得到三相交流电压控制指令为：
Figure PCTCN2022141977-appb-000007
其中
Figure PCTCN2022141977-appb-000008
图2示出本申请示例实施例的一种变流器控制系统实现变流器控制的正序向量图。
如图2所示，E p＝E dp+j0为内电势正序向量，Us p＝Us dp+jUs qp为交流电压正序向量，Uc p＝Uc dp+jUc qp为交流电压参考值正序向量，Is p＝Is dp+jIs qn为交流电流正序向量，上述向量相对于参考相位θ。当处于电压源控制方式时，Is p为流过虚拟阻抗X v的电流，根据电感特性将滞后于电感两端的电压降Us p-E p角度90°，因此：
Us p-E p＝jX vIs p        (7)
对于变流器的实际阻抗X r,也满足电感特性：
Us p-Uc p＝jX rIs p       (8)
由式(7)和(8)可见，消去Is p，从而根据Us p、E p、X v和X r计算出Uc p，即：
Figure PCTCN2022141977-appb-000009
同样可得到负序向量的关系为：
Figure PCTCN2022141977-appb-000010
其中，E n＝0为内电势负序向量，Us n＝Us dn+jUs qn为交流电压负序向量，Uc n＝Uc dn+jUc qn为交流电压参考值负序向量，Is n＝Is dn+jIs qn为交流电流负序向量，上述向量相对于参考相位θ。
由式(9)和(10)可得到式(2)。通过采用式(2)计算参考交流电压参考向量Uc dqpn，避免采用交流电流信号，因此可以有效减少振荡风险，且由于向量图与同步发电机一致，因此能够模拟与同步发电机一致的电网支撑特性。
通过调节虚拟阻抗X v可以实现模拟不同的发电机阻抗。稳态运行时，虚拟阻抗X v取值范围为0至1倍额定阻抗，较优地可将虚拟阻抗X v选取为等于实际阻抗X r；故障等大扰动引起过流时，进入暂态运行状态，通过增大虚拟阻抗X v使变流器使内电势保持稳定，即在Us p或Us n大幅变化时，通过增大虚拟阻抗X v，使图2所示的向量关系或等效的负序向量关系满足模拟不同的发电机阻抗。
图3a示出本申请示例实施例的一种交流电压控制单元AVR示意图。
如图3a所示，提供一种交流电压控制单元AVR示意图，用于实现变流器并网点交流电压的调节，通过交流电压指令值U ref与交流电压实际值U的偏差经过AVR单元31计算得到内电势的正序d轴分量E dp。根据发电机特性，内电势的正序q轴分量E dp,负序d轴分量E dn、负序q轴分量E qn均为0。
图3b示出本申请示例实施例的一种交流电压控制单元AVR实现方法框图。
图3b为本申请提供的一种AVR单元31详细实施例。交流电压指令值U ref与交流电压实际值U的偏差乘以电压下垂系数K U后得到无功调节量ΔQ，无功功率指令Q ref与无功调节量ΔQ相加，并与变流器的无功功率Q s相减后经过PI控制器得到交流电压调节量ΔE，交流电压调节量 ΔE与额定交流电压E 0相加后得到内电势的正序d轴分量E dp。
图4示出本申请示例的一种变流器控制系统框图的又一实施例。
如图4所示，变流器控制系统还包括控制误差补偿单元4和故障限流单元5。由于控制延时、电容电压波动等因素，实际变流器的输出电压与参考值向量Uc dqpn间存在偏差，较优地，可增加控制误差补偿单元4来减小该偏差。根据交流电压参考向量Uc dqpn与实际变流器交流电压向量的偏差，产生控制误差补偿量ΔUc dqpn_com，与交流电压参考向量Uc dqpn相加后作为变流器交流电压参考向量。
当变流器的过流能力受限时，较优地，可增加故障限流单元5，在暂态过流时投入，根据交流电流限制指令与实际变流器交流电流的偏差，产生故障限流控制量ΔUc dqpn_ilim，与原变流器交流电压参考向量叠加后作为变流器交流电压参考向量，实现交流电流幅值在最大交流电流幅值限值I max附近,避免变流器过流跳闸；交流电压限制指令的幅值为I max，方向为滞后于虚拟阻抗上的电压降90度。
图5示出本申请示例实施例的一种控制误差补偿单元框图。
如图5所示，控制误差补偿单元框图4应用于模块化多电平变流器的控制误差补偿，根据采集的三相下桥臂电压通过正负序分解和park变换后得到下桥臂正负序dq轴向量Vn dqpn,根据采集的三相上桥臂电压通过正负序分解和park变换后得到上桥臂正负序dq轴向量Vp dqpn，将Vn dqpn减去Vp dqpn后乘以0.5得到实际变流器交流电压向量Uc dqpn_m，交流电压参考向量Uc dqpn减去Uc dqpn_m后，经过一阶惯性环节41后得到控制误差补偿量ΔUc dqpn_com，该控制误差补偿量与交流电压参考向量Uc dqpn相加后作为变流器交流电压参考向量，以减小交流电压参考向量Uc dqpn与实际变流器交流电压向量Uc dqpn_m的误差。
图6示出本申请示例实施例的一种故障限流单元框图。
如图6所示，为故障限流单元5的详细实施例。由于虚拟阻抗上的电压降为Us dqpn-E dqpn，交流电流限制指令Isref dqpn的幅值为I max,滞后于虚拟 阻抗上的电压降90度，因此：
Figure PCTCN2022141977-appb-000011
其中J为四维向量的滞后90算子，并满足：
Figure PCTCN2022141977-appb-000012
交流电流限制指令Isref dqpn与实际变流器交流电流Is dqpn的偏差，经过PI控制器后得到故障限流控制量ΔUc dqpn_ilim，与原变流器交流电压参考向量叠加后作为变流器交流电压参考向量，实现交流电流幅值在最大交流电流幅值限值I max附近。该故障限流单元5可配置为仅在暂态过流时短时投入，短时投入的时间为1ms至1s。
图7示出本申请示例实施例的一种变流器控制方法流程图。
步骤701：由功率同步控制单元产生参考相位θ。
根据式(1)产生参考相位θ，并实现模拟发电机的调速器和机械惯性环节。
步骤702：由交流电压控制单元计算变流器的交流电压参考向量Uc dqpn。
根据式(2)由比例系数K rv,内电势E dqpn以及采集的交流电压向量Us dqpn，计算变流器的交流电压参考向量Uc dqpn：
步骤703：由交流电压指令产生单元产生三相交流电压控制指令。
根据交流电压参考向量Uc dqpn和参考相位θ，根据式(5)得到三相交流电压控制指令。
图8a、图8b示出本申请示例实施例的变流器控制方法故障穿越效果图。
图8a为采用图1a所示的控制系统的故障穿越效果，在稳态和故障暂 态全过程未采用电流闭环控制，初始电流较大，通过增大虚拟阻抗,经过50ms左右,交流电流在最大交流电流幅值限值的1.2倍额定电流附近。因此可以完全模拟发电机特性，同时不引入电流闭环控制，但需要具备一定的对变流器短时过负荷的能力。
图8b为采用图4所示的控制系统的故障穿越效果，增加控制误差补偿单元；在故障暂态期间，暂时投入故障限流单元。在故障发生后能够快速将交流电流降低至最大交流电流幅值限值的1.2倍额定电流附近。由于故障限流单元的电流指令与发电机的电流一致，仍能较好地模拟发电机特性。
上述的实施例中采用dq轴分量表示向量，也可采用αβ分量表示向量，对应关系如下:
Figure PCTCN2022141977-appb-000013
应清楚地理解，本申请描述了如何形成和使用特定示例，但本申请不限于这些示例的任何细节。相反，基于本申请公开的内容的教导，这些原理能够应用于许多其它实施例。
此外，需要注意的是，上述附图仅是根据本申请示例性实施例的方法所包括的处理的示意性说明，而不是限制目的。易于理解，上述附图所示的处理并不表明或限制这些处理的时间顺序。另外，也易于理解，这些处理可以是例如在多个模块中同步或异步执行的。
以上具体地示出和描述了本申请的示例性实施例。应可理解的是，本申请不限于这里描述的详细结构、设置方式或实现方法；相反，本申请意图涵盖包含在所附权利要求的精神和范围内的各种修改和等效设置。

Claims (18)

  1. 一种变流器控制系统，用于控制变流器模拟同步发电机，其特征在于，所述变流器控制系统包括功率同步控制单元、交流电压参考向量计算单元和交流电压指令产生单元，其中：
    所述功率同步控制单元，用于模拟同步发电机的调速器和机械惯性环节，产生参考相位；
    所述交流电压参考向量计算单元，根据内电势向量和采集的交流电压向量，并产生交流电压参考向量；
    所述交流电压指令产生单元，根据所述交流电压参考向量和所述参考相位产生三相交流电压控制指令；
    所述内电势向量根据模拟的同步发电机特性确定。
  2. 如权利要求1所述的控制系统，其特征在于，所述交流电压参考向量计算单元配置为：
    根据比例系数K rv,所述内电势向量E dqpn以及所述交流电压向量Us dqpn，计算所述交流电压参考向量Uc dqpn：
    Uc dqpn＝E dqpn+K rv(Us dqpn-E dqpn)；
    所述比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
    Figure PCTCN2022141977-appb-100001
    所述内电势向量E dqpn、交流电压向量Us dqpn、交流电压参考向量Uc dqpn均为4维向量，对应正负序上的dq轴分量；
    任一向量x dqpn定义为：x dqpn＝[x dp,x qp,x dn,x qn] T，x dp为正序d轴分量，x qp为正序q轴分量，x dn为负序d轴分量，x qn为负序d轴分量。
  3. 如权利要求1所述的控制系统，其特征在于，所述交流电压参考向量计算单元配置为：
    根据比例系数K rv,所述内电势向量E αβpn以及所述交流电压向量 Us αβpn，计算所述交流电压参考向量Uc αβpn：
    Uc αβpn＝E αβpn+K rv(Us αβpn-E αβpn)；
    所述比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
    Figure PCTCN2022141977-appb-100002
    所述内电势向量E αβpn、交流电压向量Us αβpn、交流电压参考向量Uc αβpn均为4维向量，对应正负序上的αβ轴分量；
    任一向量x αβpn定义为：x αβpn＝[x αp，x βp，x αn，x βn] T，x αp为正序α轴分量，x βp为正序β轴分量，x αn为负序α轴分量，x βn为负序β轴分量。
  4. 如权利要求2所述的控制系统，其特征在于，所述虚拟阻抗X v用于模拟发电机的阻抗：
    稳态运行时取值范围为0至1倍额定阻抗；
    暂态运行时增大虚拟阻抗X v，使内电势保持稳定。
  5. 如权利要求2所述的控制系统，其特征在于，还包括交流电压控制单元AVR,用于实现变流器并网点交流电压调节，输出内电势的正序d轴分量E dp；其中，内电势的正序q轴分量E qp，负序d轴分量E dn和负序q轴分量E qn为0。
  6. 如权利要求2所述的控制系统，其特征在于，还包括控制误差补偿单元，所述控制误差补偿单元配置为：
    根据所述交流电压参考向量Uc dqpn与实际变流器交流电压向量Uc dppn_m的偏差，产生控制误差补偿量；
    将所述控制误差补偿量与所述交流电压参考向量Uc dqpn相加，作为变流器交流电压参考向量。
  7. 如权利要求6所述的控制系统，其特征在于，还包括故障限流单元，其中：
    所述故障限流单元在暂态过流时投入，根据交流电流限制指令与实际变流器交流电流的偏差，产生故障限流控制量，与所述交流电压参考向量Uc dqpn叠加后作为所述变流器交流电压参考向量，控制交流电流幅值在最大交流电流幅值限值Imax，方向为滞后于所述虚拟阻抗X v的电压降90度。
  8. 如权利要求7所述的控制系统，其特征在于，所述故障限流单元配置为在暂态过流时短时投入，所述短时投入的时间为1ms-1s。
  9. 如权利要求1所述的控制系统，其特征在于，所述控制系统用于直流输电变流器、储能变流器、微网变流器、光伏逆变器或风电变流器的至少一种。
  10. 一种变流器控制方法，用于控制变流器模拟同步发电机，其特征在于，包括如权利要求1-9中任一项所述的变流器控制系统：
    所述功率同步控制单元模拟发电机的调速器和机械惯性环节，产生参考相位；
    所述交流电压参考向量计算单元，根据内电势向量和采集的交流电压向量，根据发产生交流电压参考向量；
    所述交流电压指令产生单元，根据所述交流电压参考值向量和所述参考相位产生三相交流电压控制指令；
    所述内电势向量根据模拟的同步发电机特性确定。
  11. 如权利要求10所述的控制方法，其特征在于，所述交流电压参考向量计算单元配置为：
    根据比例系数K rv,内电势E dqpn以及交流电压向量Us dqpn，计算交流电压参考值向量Uc dqpn：
    Uc dqpn＝E dqpn+K rv(Us dqpn-E dqpn)
    所述比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
    Figure PCTCN2022141977-appb-100003
    所述虚拟阻抗X v用于模拟发电机的阻抗，稳态运行时取值范围为0至1倍额定阻抗；暂态运行时增大虚拟阻抗X v，使内电势保持稳定。
  12. 如权利要求10所述的控制方法，其特征在于，所述交流电压参考向量计算单元配置为：
    根据比例系数K rv,所述内电势向量E αβpn以及所述交流电压向量Us αβpn，计算所述交流电压参考向量Uc αβpn：
    Uc αβpn＝E αβpn+K rv(Us αβpn-E αβpn)；
    所述比例系数K rv根据变流器的虚拟阻抗X v和变流器实际阻抗X r确定：
    Figure PCTCN2022141977-appb-100004
    所述内电势向量E αβpn、交流电压向量Us αβpn、交流电压参考向量Uc αβpn均为4维向量，对应正负序上的αβ轴分量；
    任一向量x αβpn定义为：x αβpn＝[x αp，x βp，x αn，x βn] T，x αp为正序α轴分量，x βp为正序β轴分量，x αn为负序α轴分量，x βn为负序β轴分量。
  13. 如权利要求10所述的控制方法，其特征在于，还包括：
    交流电压控制单元AVR实现变流器并网点交流电压调节，输出内电势的正序d轴分量E dp；其中，内电势的正序q轴分量E qp，负序d轴分量E dn和负序q轴分量E qn为0。
  14. 如权利要求11所述的控制方法，其特征在于，还包括控制误差补偿单元，所述控制误差补偿单元配置为：
    控制误差补偿单元根据所述交流电压参考向量Uc dqpn与实际变流器交流电压向量Uc dppn_m的偏差，产生控制误差补偿量；
    将所述控制误差补偿量与所述交流电压参考向量Uc dqpn相加，作为 变流器交流电压参考向量。
  15. 如权利要求14所述的控制方法，其特征在于，还包括：
    故障限流单元在暂态过流时投入，根据交流电流限制指令与实际变流器交流电流的偏差，产生故障限流控制量，与所述交流电压参考向量Uc dqpn叠加后作为所述变流器交流电压参考向量，控制交流电流幅值在最大交流电流幅值限值Imax，方向为滞后于所述虚拟阻抗X v的电压降90度。
  16. 如权利要求15所述的控制方法，其特征在于，所述故障限流单元配置为在暂态过流时短时投入，所述短时投入的时间为1ms-1s。
  17. 一种程序产品，其特征在于，包括如权利要求1-9中任一项所述的变流器控制系统。
  18. 一种电子设备，其特征在于，包括如权利要求17所述的程序产品。
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