Semi-physical simulation model for excitation converter controller of large variable-speed pumped storage unit

Abstract

The invention provides a semi-physical simulation model for an excitation converter controller of a large variable-speed pumped storage unit. The semi-physical simulation model comprises a grid-side converter controller semi-physical simulation model and a machine-side converter controller semi-physical simulation model based on an alternating-current excitation system control principle. The model has a unified standard interface to adapt to different unit models; the model can automatically adjust an excitation converter controller algorithm according to working conditions so as to adapt to different operation working conditions of the unit; the excitation converter controller under different operation conditions is modularized to adapt to future unit condition expansion requirements, and later maintenance is flexible and convenient. An MEX packaging model is adopted, so that the model is closed and is separated from controller parameter setting, and achievements of all parties are protected to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical field of control simulation of large variable speed pumped storage units, and more specifically to a semi-physical simulation model of an AC excitation control system AECS (AC excitation control system) of a large variable speed pumped storage unit. Background Art

[0002] Variable speed pumped storage units are important equipment for the consumption of new energy, with the characteristics of high economy, large capacity, wide power regulation range and high speed. In the context of large-scale renewable energy access to the power grid, variable speed pumped storage units can undertake tasks such as peak-to-valley shifting and frequency regulation, help the consumption of clean energy, maintain the stability of the power grid frequency and improve the safety level of the power grid.

[0003] Conventional pumped-storage power stations have many problems such as inflexible power adjustment, low turbine efficiency, increased cavitation, increased wear and vibration, etc. due to the fixed speed operation of the units. In order to solve the above problems, variable speed pumped-storage units and their control technology came into being. Compared with conventional fixed speed pumped-storage units, variable speed pumped-storage units are mainly composed of generator motors, AC excitation converters and control systems, speed regulators and control systems, coordinated control systems and reversible turbines. As the key equipment of variable speed pumped-storage units, AC excitation converters and control systems can not only realize variable speed constant frequency and millisecond-level decoupling control of active and reactive power, but also adjust the input power of the pump working condition and improve the operating performance of the turbine working condition. Based on the above advantages of variable speed pumped-storage units, domestic and foreign research institutions have invested a lot of energy in studying the key technologies of AC excitation converters and their control of variable speed pumped-storage units.

[0004] In the multi-stage flexible coordinated control process of VSPS units, the physical characteristics and control objectives of VSPS units in different stages are different, which makes the control model and controller parameters of AECS change with the changes of unit stages. That is, AECS has the physical characteristics of adaptive control parameters. In order to truly simulate AECS, its model also needs to be designed with adaptive physical characteristics. It is difficult for the MATLAB / Simulink offline simulation model to accurately restore this control characteristic.

[0005] The large variable speed pumped storage unit proposed in the present invention application refers to a variable speed pumped storage unit with a single capacity of 400 MW or above. The control technology of the AC excitation converter of a single 400 MW variable speed pumped storage unit in China is still in the research stage. Since there is no single 400 MW variable speed pumped storage unit put into operation, the correctness and reliability of the control strategy of the excitation converter controller cannot be verified. Summary of the invention

[0006] To solve the above problems, the present invention proposes a semi-physical simulation model of an excitation converter controller for a large variable speed pumped storage unit, through which the excitation process of the unit can be accurately simulated. This AECS semi-physical simulation model can not only verify the correctness and reliability of the control strategy of the excitation converter controller, but also greatly shorten the physical development cycle of the excitation converter controller. In one embodiment, the semi-physical simulation model of the excitation converter controller is written in C language and encapsulated as an S-function model through MATLAB's MEX, which is convenient for later physical development code transplantation.

[0007] The present invention proposes a standardized design method for a semi-physical simulation model of an excitation current converter controller of a large variable speed pumped storage unit, with a unified standard interface, which can adapt to different unit models.

[0008] The present invention proposes an automated design method for a semi-physical simulation model of an excitation current converter controller for a large variable speed pumped storage unit, which automatically adjusts the excitation current converter controller algorithm according to the operating conditions to adapt to different operating conditions of the unit.

[0009] The present invention proposes a modular design method for a semi-physical simulation model of an excitation converter controller for a large variable speed pumped storage unit, which modularizes the algorithms of the excitation converter controller under different operating conditions, which can not only improve the maintainability of the semi-physical model, but also improve its scalability and flexibility.

[0010] The present invention proposes a closed design method for a semi-physical simulation model of an excitation converter controller for a large variable speed pumped storage unit. The semi-physical excitation converter controller MEX encapsulation based on S-function makes the semi-physical model of the excitation converter controller closed and separated from the controller parameter setting, thereby protecting the achievements of all parties to the greatest extent.

[0011] The present invention proposes a standard interface for a semi-physical simulation model of an excitation converter controller of a large variable speed pumped storage unit. Since the excitation control system includes two independent parts, a grid-side converter controller and a machine-side converter controller, its semi-physical model is also divided into two independent parts, a grid-side part and a machine-side part.

[0012] The present invention proposes a semi-physical simulation model of an excitation current converter controller of a variable speed pumped storage unit. The model can automatically adjust the excitation current converter controller parameters according to the state instructions of the unit coordination controller to adapt to the needs of switching between different operating conditions of the unit.

[0013] The present invention proposes a semi-physical simulation model of an excitation converter controller for a large variable speed pumped storage unit, and modularizes the algorithms of the model under different operating conditions, which can not only improve the maintainability of the semi-physical model, but also improve its scalability and flexibility.

[0014] The present invention proposes a semi-physical simulation model of an excitation converter controller for a large variable speed pumped storage unit. MEX is used to encapsulate the model, so that the model is closed and separated from the controller parameter setting, thereby protecting the achievements of all parties to the greatest extent.

[0015] The embodiments of the present invention application have at least the following advantages or beneficial effects: it can effectively verify the correctness and reliability of the excitation control strategy of large pumped storage units, lay a model foundation for the simulation verification of the coordinated control of the unit, and provide software support for the physical development of the excitation controller. The model has the characteristics of standardization, automation, modeling and closure. Its advantages are strong maintainability, portability, confidentiality and extensibility. It can not only verify the correctness and reliability of the control strategy of the excitation converter controller, but also provide effective guidance and basis for the physical development of the excitation converter controller of large variable speed pumped storage units. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a large variable speed pumped storage power station.

[0017] Figure 2 It is a block diagram of the control system of a large variable speed pumped storage unit.

[0018] Figure 3 Positive direction of the electrical variable of the grid-side converter.

[0019] Figure 4 This is the principle block diagram of the grid-side converter controller (steady state).

[0020] Figure 5 This is the principle block diagram of the machine-side converter controller (steady state).

[0021] Figure 6 It is a schematic diagram of the process of establishing a semi-physical simulation model of an AC excitation control system.

[0022] Figure 7 It is the internal structure block diagram of the semi-physical model of the grid-side converter controller (steady state).

[0023] Figure 8 It is the internal structure block diagram of the semi-physical model of the machine-side converter controller (steady state). DETAILED DESCRIPTION

[0024] The present invention proposes a semi-physical simulation model of an excitation converter controller of a large variable speed pumped storage unit (abbreviated as: excitation converter controller model / model / system) and an establishment method, which relates to the control and simulation technology of an excitation converter of a large variable speed pumped storage unit, and especially includes the following contents: a semi-physical outer loop controller based on a variable function, a semi-physical inner loop controller based on the same function, a semi-physical control system core based on the inner loop and the outer loop, automatic reading of controller variables based on a dynamic link library, automatic reading of unit fixed parameters based on a static link library, and a MEX encapsulation of a semi-physical excitation converter controller based on an S-function.

[0025] The outstanding feature of the present invention application is that a standardized, automated and modular semi-physical simulation model is proposed. The semi-physical simulation system of the excitation converter controller has a unified standard interface to adapt to different unit models; the excitation converter controller algorithm is automatically adjusted according to the working conditions to adapt to different operating conditions of the unit; the excitation converter controllers of different operating conditions are modularized to meet the future unit operating condition expansion requirements, and the later maintenance is flexible and convenient; the semi-physical excitation converter controller MEX encapsulation based on S-function makes the semi-physical model closed and separated from the controller parameter setting, protecting the achievements of all parties to the greatest extent. The semi-physical simulation model of the excitation converter controller can automatically identify the unit model and read the corresponding unit parameters and excitation converter controller variables. It has a high degree of automation and good compatibility, scalability and confidentiality.

[0026] Example 1

[0027] Figure 1 It is a schematic diagram of a large variable speed pumped storage unit. Figure 2 This is a block diagram of the control system for a large variable speed pumped storage unit. Figure 1 , Figure 2 As shown, the large variable speed pumped storage unit includes an AC excitation system (AES), a speed control system, a monitoring system, a reversible pump turbine, a waterway, a generator motor and a coordinated controller.

[0028] The AC excitation system (AES) includes the grid-side converter (GSC) and its controller and the generator-side converter (RSC) and its controller. The control principle of the AC excitation system is first introduced below. The excitation converter controller / AC excitation controller / controller refers to the grid-side converter controller and the generator-side converter controller.

[0029] The positive direction of GSC related electricity is Figure 3 As shown, where: R GSC , L GSC are the resistance and inductance of the GSC filter respectively; C is the DC side filter capacitor; i GSC is the GSC grid-side current; v is the GSC output voltage; e is the grid voltage; Udc is the GSC DC side voltage.

[0030] Adopting vector control strategy, the d-axis is oriented to the grid voltage vector, e d =U g , e q =0, mathematical model of grid-side converter GSC:

[0031]

[0032] Where: subscripts d and q represent d-axis and q-axis components respectively (the same applies below); R L P is the equivalent resistance of the GSC DC side load; GSC , Q GSC are the active and reactive power consumed by GSC respectively; ω g is the grid angular frequency.

[0033] From the above mathematical model, it can be seen that the d-axis output voltage v of the grid-side converter controller is d Controllable d-axis current i GSCd , and then through i GSCd Control the DC voltage transient; through the q-axis output voltage v of the GSC q Controllable q-axis current i GSCq , and then through i GSCq Control GSC to consume reactive power Q GSC Therefore, a double closed-loop vector control system for GSC can be designed based on the PI controller, such as Figure 4 shown.

[0034] Adopting vector control strategy, the d-axis is oriented to the grid voltage vector, u sd =U g ,u sq =0,ψ sd =0,ψ sq =ψ1, mathematical model of the machine-side converter RSC:

[0035]

[0036] Where: ψ1 represents the per unit value of the DFIM stator flux amplitude; subscripts d and q represent the d-axis and q-axis components respectively; i r is the rotor current; i s is the stator current; u r is the rotor voltage; u s is the stator voltage; L is the inductance; P and Q are the power output of the unit; Rr is the rotor resistance; α is the motor leakage coefficient; Lr is the rotor inductance; ω slp Indicates the slip angular frequency; ω g is the grid angular frequency; ω rIndicates the rotor angular frequency; L s Represents stator inductance; L m Indicates mutual induction.

[0037] From the above mathematical model, it can be seen that the d-axis output excitation voltage u of the machine-side converter is rd The DFIM rotor d-axis current i can be controlled rd , and then through i rd Control the active power of the variable speed pumped storage unit; output the excitation voltage u through the q axis of the machine-side converter rq The DFIM rotor q-axis current i can be controlled rq , and then through i rq Control the active power of the VSPS unit. Therefore, a double closed-loop vector control system for RSC can be designed based on the PI controller, such as Figure 5 shown.

[0038] Example 2

[0039] The present invention proposes the semi-physical simulation model of the excitation converter controller based on the control principle of the AC excitation system. The model includes a semi-physical simulation model of the grid-side converter controller and a semi-physical simulation model of the machine-side converter controller. Figure 6 A flow chart is established for a semi-physical simulation model of an excitation converter controller, which includes the above two mathematical models. In one implementation, the model is established in MATLAB using the simulink simulation tool and a simulation verification is performed.

[0040] Example 3

[0041] The semi-physical simulation model of the excitation converter controller includes a standard interface. The standard interface of the semi-physical simulation model of the grid-side converter controller is shown in the following table: the input includes the grid-side converter controller state S, the control mode CTRL, the grid-side converter controller enable EN, the grid-side current q-axis component reference value igc_q_ref, the grid-side current instantaneous value igc_dq (including the d-axis component igc_d, the q-axis component igc_q), the angular velocity w, the stator voltage instantaneous value us_dq (including the d-axis component us_d, the q-axis component us_q), the DC voltage instantaneous value Vdc_V, the phase Theta_rad, a total of 11 input interfaces; the output is the grid-side converter control voltage reference value Uref_gsc.

[0042]

[0043] The standard interface of the semi-physical simulation model of the machine-side converter controller is shown in the following table: The input includes the machine-side converter controller state S, the control mode CTRL, the machine-side converter controller enable EN, the instantaneous value of the rotor current ir_dq, the instantaneous value of the stator current is_dq (including the d-axis component is_d and the q-axis component is_q), the stator angular velocity w, the rotor angular velocity wr, the instantaneous values ​​of active power and reactive power P and Q, and the set value of active power and reactive power P set and Q set , grid voltage instantaneous value ug_dq (including d-axis component ug_d, q-axis component ug_q), stator voltage instantaneous value us_dq (including d-axis component us_d, q-axis component us_q), DC voltage instantaneous value Vdc_V, phase difference Theta_slip_rad, a total of 19 interfaces; the output is the machine-side converter control voltage reference value Uref_rsc.

[0044]

[0045] Based on the above unified standard interface, the semi-physical simulation model of the excitation converter controller has better adaptability in the development and debugging of control systems for large variable speed pumped storage units.

[0046] Example 4

[0047] The semi-physical simulation model of the excitation current converter controller can interact with any type of coordination controller. The model can automatically adjust the excitation current converter controller parameters according to the state instructions of the unit coordination controller to adapt to the needs of switching between different operating conditions of the unit.

[0048] The above excitation converter controller parameters include unit parameters and controller parameters. Unit parameters are static parameters, which only change when the unit changes, and will not change when the operating condition is switched. Unit parameters include stator rated voltage, rotor rated voltage, DC voltage rated value, stator-rotor mutual inductance, rotor inductance, DC voltage limit value, and rotor voltage polar coordinate amplitude limit value.

[0049] Controller parameters include controller variables and initial values. Controllers refer to grid-side converter controllers and generator-side converter controllers. Controller parameters include static parameters and dynamic parameters. Controller initial values ​​are all static parameters, which only change when the unit changes, and will not change when the operating condition switches; while controller variables are all dynamic parameters, which change when the operating condition switches.

[0050] The controller variables include the controller's integral coefficient Ki, proportional coefficient Kp, limit value (UP, DOWN) and initial value INIT. The controller's initial value is calculated from the rotor current d, q component initial value (ird_0, irq_0), rotor angular frequency initial value (wr_0), stator current d, q component initial value (isd_0, isq_0), rotor voltage d, q component initial value (urd_0, urd_0), etc.

[0051] The above dynamic parameters are automatically loaded when the excitation converter controller model is initialized, and the static parameters are solidified inside the model. The excitation converter controller model will automatically adjust the dynamic parameters according to the unit operating conditions, that is, automatically adjust the controller variables.

[0052] Example 5

[0053] Modularizing the algorithm of the excitation converter controller model under different operating conditions can not only improve its maintainability, but also improve its scalability and flexibility.

[0054] like Figure 7 and Figure 8 As shown in the figure, the semi-physical simulation model of the generator-side converter controller (also called: generator-side converter controller) and the semi-physical simulation model of the grid-side converter controller (also called: grid-side converter controller) are both double closed loops with dq axis decoupling, and the controller structures are both PI controllers. The d-axis includes an outer loop PI controller and an inner loop PI controller; the q-axis includes an outer loop PI controller and an inner loop PI controller.

[0055] Based on the PI controller, a semi-physical simulation model of the grid-side converter controller is designed for the dual closed-loop vector control system of the grid-side converter, and a semi-physical simulation model of the machine-side converter controller is designed for the dual closed-loop vector control system of the machine-side converter, the dual closed-loop vector control system for the grid-side converter and the dual closed-loop vector control system for the machine-side converter.

[0056] The PI controller is designed as a general module piCtrlRun(double errIn,PICTRL*PICTRLVal).

[0057] PICTRL is a structure array, which contains specific controller parameters, such as controller coefficient, upper limit, lower limit, initial value, etc. *PICTRLVal is an array pointer defined as PICTRL type, which automatically reads the corresponding controller parameters according to the unit operating conditions.

[0058] *PICTRLVal is an array pointer pointing to controller parameters, and automatically reads corresponding controller parameters according to the unit operating conditions. In one implementation, the array pointed to by *PICTRLVal has 20 columns (4*5), and the number of rows is determined by the number of operating conditions.

[0059] double is a double-precision floating point data type. errIn is the error input by the controller.

[0060] like Figure 6 and Figure 7 As shown in the figure, the inner loop controller structure of the semi-physical simulation model of the machine-side converter controller and the semi-physical simulation model of the grid-side converter controller does not change when the working conditions are switched, and can be designed as a common module commonPICal (double*irdq_ref, double w, double wr, double*is_dq, double*ir_dq, double Vdc_V, double Theta_slip_rad, double*Uctrl_rc), that is, the same function inner loop module design. irdq_ref represents the excitation current reference value; Uctrl_rc represents the rotor control voltage.

[0061] like Figure 6 and Figure 7 As shown, the outer loop controller structure of the semi-physical simulation model of the machine-side converter controller and the semi-physical simulation model of the grid-side converter controller will change when the operating conditions switch, and the module design can be carried out according to the operating conditions, that is, the variable function outer loop module design.

[0062] As mentioned above, when the generator is in no-load condition, the outer loop function of the generator-side converter controller can be designed as GenSyn(ug_dq, us_dq, *irdq_ref, *PICTRLVal).

[0063] As mentioned above, in the power generation condition, the outer loop function of the machine-side converter controller can be designed as Gen(Pref, P, Qref, Q, S, *irdq_ref, *PICTRLVal), and Qref = 0 in the power generation phase modulation condition. Pref represents the active power command value, Qref represents the reactive power command value, and S represents the operating condition flag.

[0064] As mentioned above, when the generator is load-shedding, the outer loop function of the machine-side converter controller can be designed as Gen(Pref, P, Qref, Q, S, *irdq_ref, *PICTRLVal), Pref=0, Qref=0.

[0065] As mentioned above, during the generator electrical braking condition, the outer loop function of the machine-side converter controller can be designed as GenBrake(rd_ref,id,rq_ref,iq,*PICTRLVal); ird_ref=0, irq_ref=0; id and iq represent the d-axis and q-axis components of the excitation current respectively, and rd_ref and rq_ref represent the d-axis and q-axis reference values ​​of the excitation current respectively.

[0066] As mentioned above, during the electric starting condition, the outer loop function of the machine-side converter controller can be designed as PumpStart(ug_dq, us_dq, *irdq_ref, *PICTRLVal).

[0067] As mentioned above, in the electric synchronous working condition, the outer loop function of the machine-side converter controller can be designed as PumpSyn(ug_dq,us_dq,*irdq_ref,*PICTRLVal).

[0068] As mentioned above, during pumping operation, the outer loop function of the machine-side converter controller can be designed as Pump(Pref, P, Qref, Q, S, *irdq_ref, *PICTRLVal), and Qref=0 during pumping phase adjustment.

[0069] As mentioned above, when pumping load is shed, the outer loop function of the machine-side converter controller can be designed as Pump(Pref, P, Qref, Q, S, *irdq_ref, *PICTRLVal), Pref=0, Qref=0.

[0070] As mentioned above, in the pumping electrical braking condition, the outer loop function of the machine-side converter controller can be designed as PumpBrake(rd_ref,id,rq_ref,iq,*PICTRLVal); ird_ref=0, irq_ref=0.

[0071] The excitation converter controller model automatically adjusts controller parameters according to the operating conditions, and can be designed as ctrlSysCore(double S, double w, double*ir_dq, double*is_dq, double wr, double Vdc_V, double Theta_slip_rad, double Pref, double P, double Qref, double Q, double*ug_dq, double*us_dq, double*Uctrl_rc), where S is the unit operating condition flag, and the outer loop function is switched through the Switch-case structure.

[0072] The design of the excitation converter controller model module is mainly explained by taking the semi-physical simulation model of the machine-side converter controller as an example, and the semi-physical simulation model of the grid-side converter controller is similar to it.

[0073] Example 6

[0074] The semi-physical converter excitation controller based on S-function adopts MEX package, which makes the semi-physical model of converter excitation controller closed and separated from controller parameter setting.

[0075] The parameter file is saved as csv format using xls file. The csv format file can be opened and edited using a table. The semi-physical excitation converter controller based on S-function uses csv format file for data reading.

[0076] The unit parameters and controller initial values ​​will no longer change after the semi-physical simulation model starts running. They are solidified as internal parameters of the model, and the csv format file only stores the controller variables.

[0077] The semi-physical simulation model of the excitation current converter controller of the large variable speed pumped storage unit of the present invention runs on a computer system.

[0078] The embodiment of the semi-physical simulation model of the excitation converter controller of a large variable speed pumped storage unit of the present invention can be implemented in the form of a method, a system, or a computer program product. The present invention can be implemented in the form of a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention can be implemented in 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 codes.

Claims

1. A semi-physical simulation model of an excitation converter controller for a large variable speed pumped storage unit, characterized in that: Contains: a semi-physical simulation model of the grid-side converter controller and a semi-physical simulation model of the machine-side converter controller based on the control principle of the AC excitation system.

2. The semi-physical simulation model of the AC excitation system of a large variable speed pumped storage unit according to claim 1 is characterized in that: The semi-physical simulation model of the grid-side converter controller has a standard interface. The input of the standard interface includes the grid-side converter controller state, the grid-side converter controller enable, the grid-side current q-axis component reference value igc_q_ref, the grid-side current d-axis and q-axis component instantaneous value igc_dq, the angular velocity w_pu, the stator voltage d-axis and q-axis component instantaneous value us_dq, the DC voltage instantaneous value Vdc_V and the phase Theta_rad. The output of the standard interface is the grid-side converter control voltage reference value Uref_gsc.

3. The semi-physical simulation model of AC excitation system of large variable speed pumped storage unit according to claim 1 is characterized in that: The semi-physical simulation model of the machine-side converter controller has a standard interface, the input of which includes: machine-side converter controller state S, control mode CTRL, machine-side converter controller enable EN, rotor current instantaneous value ir_dq, stator current instantaneous value is_dq, stator angular velocity w, rotor angular velocity wr, active power and reactive power instantaneous values ​​P and Q, active power and reactive power set value P set and Q set , grid voltage instantaneous value ug_dq, stator voltage instantaneous value us_dq, DC voltage instantaneous value Vdc_V and phase difference Theta_slip_rad, and the output is the machine-side converter control voltage reference value Uref_rsc.

4. The semi-physical simulation model of AC excitation system of large variable speed pumped storage unit according to claim 1 is characterized in that: The semi-physical simulation model of the excitation current converter controller automatically adjusts the parameters of the excitation current converter controller according to the state instructions of the unit coordination controller to adapt to the needs of switching between different operating conditions of the unit.

5. The semi-physical simulation model of AC excitation system of large variable speed pumped storage unit according to claim 4 is characterized in that: The excitation converter controller parameters include unit parameters and controller parameters; unit parameters are all static parameters, which only change when the unit changes, and will not change when the operating condition switches; controller parameters include static parameters and dynamic parameters, and the controller initial values ​​are all static parameters, which only change when the unit changes, and will not change when the operating condition switches; The controller variables are all dynamic parameters, which change when the operating conditions switch; the dynamic parameters are automatically loaded when the excitation converter controller is initialized, and the static parameters are solidified inside the model; the semi-physical simulation model of the excitation converter controller will automatically adjust the dynamic parameters according to the unit operating conditions, that is, automatically adjust the controller variables.

6. The semi-physical simulation model of AC excitation system of large variable speed pumped storage unit according to claim 5 is characterized in that: Design of a semi-physical simulation model of the grid-side converter controller based on the PI controller for the dual closed-loop vector control system of the grid-side converter, and a semi-physical simulation model of the machine-side converter controller for the dual closed-loop vector control system of the machine-side converter, for the grid-side converter and for the machine-side converter; The PI controller is designed as a general module piCtrlRun (double errIn, PICTRL*PICTRLVal); double is a double-precision floating-point data type; PICTRL is a structure array that contains controller parameters, *PICTRLVal is an array pointer defined as a PICTRL type, and the corresponding controller parameters are automatically read according to the unit operating conditions; errIn is the error of the controller input.

7. The semi-physical simulation model of AC excitation system of large variable speed pumped storage unit according to claim 6 is characterized in that: The inner loop controller of the semi-physical simulation model of the machine-side converter controller and the semi-physical simulation model of the grid-side converter controller are designed as a common module: commonPICal(double*irdq_ref,double w,double wr,double*is_dq,double*ir_dq,double Vdc_V,double Theta_slip_rad,double*Uctrl_rc), where irdq_ref represents the excitation current reference value; Uctrl_rc represents the rotor control voltage.

8. The semi-physical simulation model of AC excitation system of large variable speed pumped storage unit according to claim 6 is characterized in that: The outer loop controllers of the semi-physical simulation model of the generator-side converter controller and the semi-physical simulation model of the grid-side converter controller are modularly designed according to the operating conditions.

9. The semi-physical simulation model of AC excitation system of large variable speed pumped storage unit according to claim 8 is characterized in that: When the generator is in no-load condition, the outer loop function of the semi-physical simulation model of the generator-side converter controller is designed as GenSyn(ug_dq,us_dq,*irdq_ref,*PICTRLVal); In the power generation condition, the outer loop function of the semi-physical simulation model of the machine-side converter controller is designed as Gen(Pref, P, Qref, Q, S, *irdq_ref, *PICTRLVal), Qref = 0 in the power generation phase modulation; Pref represents the active power command value, Qref represents the reactive power command value, and S represents the operating condition flag; When the generator is shedding load, the outer loop function of the semi-physical simulation model of the machine-side converter controller is designed as Gen(Pref, P, Qref, Q, S, *irdq_ref, *PICTRLVal), Pref = 0, Qref = 0; During the generator electrical braking condition, the outer loop function of the semi-physical simulation model of the machine-side converter controller is designed as GenBrake(rd_ref,id,rq_ref,iq,*PICTRLVal); ird_ref=0, irq_ref=0; id, iq represent the d-axis and q-axis components of the excitation current respectively, and rd_ref, rq_ref represent the d-axis and q-axis reference values ​​of the excitation current respectively; In the electric starting condition, the outer loop function of the semi-physical simulation model of the machine-side converter controller is designed as PumpStart(ug_dq,us_dq,*irdq_ref,*PICTRLVal); In the electric synchronous working condition, the outer loop function of the semi-physical simulation model of the machine-side converter controller is designed as PumpSyn(ug_dq,us_dq,*irdq_ref,*PICTRLVal); In pumping operation, the outer loop function of the semi-physical simulation model of the machine-side converter controller is designed as Pump(Pref, P, Qref, Q, S, *irdq_ref, *PICTRLVal), and Qref = 0 in pumping phase adjustment; When pumping load shedding, the outer loop function of the semi-physical simulation model of the machine-side converter controller is designed as Pump(Pref, P, Qref, Q, S, *irdq_ref, *PICTRLVal), Pref = 0, Qref = 0; In the pumping electrical braking condition, the outer loop function of the semi-physical simulation model of the machine-side converter controller is designed as PumpBrake(rd_ref,id,rq_ref,iq,*PICTRLVal); ird_ref=0, irq_ref=0.

10. The semi-physical simulation model of AC excitation system of large variable speed pumped storage unit according to claim 5, characterized in that: The semi-physical simulation model of the excitation converter controller adopts MEX encapsulation to make it closed and separated from the controller parameter setting. The controller variables are stored in a csv format file that can be opened and edited with a table. The semi-physical simulation model of the excitation converter controller reads the controller variables from the csv format file, and the unit parameters and controller initial values ​​are solidified in the semi-physical simulation model of the excitation converter controller.

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