Parameter design method and control device of variable-speed pumped storage system

Abstract

The invention discloses a parameter design method and control device for a variable-speed pumping and storage system, and belongs to the technical field of variable-speed pumping and storage system control, and the method comprises the steps: determining a current loop control object of a machine-side converter, and designing a rotor d-axis current bandwidth and a rotor q-axis current bandwidth; determining a machine side converter power loop control object, and designing an active power loop bandwidth and a reactive power loop bandwidth; determining a current loop control object of the grid-side converter, and designing a grid-side d-axis current bandwidth and a grid-side q-axis current bandwidth; and determining a grid-side converter DC voltage loop control object, and designing a grid-side converter DC voltage loop bandwidth. The internal model control decoupling design is adopted, the setting complexity is reduced, the coupling effect between the machine-side converter and the grid-side converter is reduced, and the system performance, stability and design flexibility are improved.

Description

Technical Field

[0001] This invention relates to the field of variable speed pumped storage system control technology, and in particular to a parameter design method and control device for a variable speed pumped storage system. Background Technology

[0002] In new power systems, the penetration rate of renewable energy sources such as wind power and photovoltaics continues to rise, but their intermittent and random characteristics pose challenges to the stable operation of the power grid. Pumped storage technology is currently the most economical and largest-capacity energy storage device, and a key technology for improving the absorption of new energy sources. Traditional constant-speed pumped storage units have a fixed rotational speed and limited regulation capability, making it difficult to respond to the grid's regulation needs in real time under pumping conditions. Variable-speed pumped storage systems use AC excitation technology to achieve rapid and flexible adjustment of the unit, offering advantages over constant-speed units such as higher operating efficiency, wider power regulation range, and faster response speed. Therefore, developing variable-speed pumped storage technology is of great significance for improving the stable operation of the new energy power grid.

[0003] Variable-speed pumped-storage systems employ a back-to-back converter structure, including generator-side and grid-side converters. Their control performance directly impacts system operational stability. Currently, commonly used vector control strategies require multiple control loops to design proportional-integral (PI) controller parameters for precise control: 1) Generator-side converters need inner-loop current PI parameters to achieve rapid tracking of excitation and torque currents, and outer-loop power PI parameters to ensure accurate output power tracking of grid dispatch commands. 2) Grid-side converters need inner-loop current PI parameters to control grid-side current, and outer-loop DC voltage PI parameters to maintain DC bus voltage stability. However, variable-speed pumped-storage systems involve numerous converter parameter designs and complex tuning processes. Strong coupling exists between various PI parameters. Traditional tuning methods based on classical control theory are labor-intensive and time-consuming, making it difficult to achieve globally optimal performance under pumping or power generation conditions. Furthermore, improper parameter tuning can lead to system oscillations and instability, severely restricting stable system operation. Summary of the Invention

[0004] The present invention aims to provide a parameter design method and control device for a variable speed pumped storage system that simplifies the tuning process, reduces the number of parameters to be tuned, and effectively reduces internal coupling. This is of great significance for effectively improving the stable operation of the variable speed pumped storage system.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A parameter design method for a variable-speed pumped-storage system includes, Determine the control object of the machine-side converter current loop. Establish the transfer function of the internal model controller of the current loop of the machine-side converter. Design the d-axis current bandwidth of the machine-side rotor. And the q-axis current bandwidth of the rotor on the machine side Complete the tuning of the current loop parameters of the machine-side converter; Determine the control object of the power loop of the machine-side converter. Establish the transfer function of the internal model controller of the power loop of the machine-side converter. Design active power loop bandwidth and reactive power loop bandwidth Complete the power loop parameter tuning of the machine-side converter; Determine the control object of the grid-side converter current loop. Establish the transfer function of the internal model controller of the current loop of the grid-side converter. Design the d-axis current bandwidth of the grid-side rotor. and grid-side rotor q-axis current bandwidth Complete the current loop parameter tuning of the grid-side converter; Determine the DC voltage loop control object of the grid-side converter. Establish the transfer function of the DC voltage loop internal model controller for the grid-side converter. Design the DC voltage loop bandwidth on the grid side. Complete the DC voltage loop parameter tuning of the grid-side converter.

[0006] Furthermore, the transfer function of the internal mode controller of the current loop of the machine-side converter is: , in, It is the bandwidth of the d-axis current of the rotor on the machine side. It is the bandwidth of the q-axis current of the rotor on the machine side. It is a differential operator. It is the rotor resistance on the machine side. It is the leakage coefficient ,in, It is a magnetically excited inductor. It is a stator inductor. It is the rotor inductance; It is the d-axis inductance of the rotor on the machine side. It is the q-axis inductance of the rotor on the machine side.

[0007] Furthermore, the transfer function of the power loop inner mode controller of the machine-side converter is: , in, It is the bandwidth of the d-axis current of the rotor on the machine side. It is the bandwidth of the q-axis current of the rotor on the machine side. It is the active power loop bandwidth. It is the reactive power loop bandwidth.

[0008] Furthermore, the transfer function of the grid-side converter current loop internal mode controller is: , in, It is the bandwidth of the d-axis current of the grid-side rotor. It is the bandwidth of the q-axis current of the grid-side rotor. It is the grid-side rotor resistance. It is a differential operator. It is a grid-side filter inductor.

[0009] Furthermore, the transfer function of the DC voltage loop inner mode controller of the grid-side converter is: , in, It is the DC voltage loop bandwidth on the grid side. It is a differential operator; ,in, It is the steady-state value of the d-axis component of the grid voltage. yes The voltage at an operating point, i.e., the steady-state value of the DC bus voltage. It is a DC bus capacitor.

[0010] Furthermore, the expression for the control object of the generator-side converter current loop is: , in, It is the rotor resistance of the machine-side converter. It is a differential operator. It is the d-axis inductance of the rotor of the machine-side converter. It is the q-axis inductance of the rotor of the machine-side converter. It is the leakage coefficient ,in, It is a magnetically excited inductor. It is a stator inductor. It is the rotor inductance.

[0011] Furthermore, the expression for the control object of the generator-side converter power loop is: , in, It is the active power loop bandwidth. It is the reactive power loop bandwidth. It is a differential operator.

[0012] Furthermore, the expression for the control object of the grid-side converter current loop is: , in, It is the rotor resistance of the grid-side converter. It is a differential operator. It is a grid-side filter inductor.

[0013] Furthermore, the expression for the control object of the DC voltage loop of the grid-side converter is: , in, It is the change in the d-axis current on the grid side. It is the change in DC bus voltage. It is a differential operator. ,in, It is the steady-state value of the d-axis component of the grid voltage. yes The voltage at an operating point, i.e., the steady-state value of the DC bus voltage. It is a DC bus capacitor.

[0014] A control device for a variable-speed pumped-storage system, executing the parameter design method for a variable-speed pumped-storage system as described in any one of the above, includes a grid-side controller and a machine-side controller; the first terminal of the grid-side controller is the first terminal of the first terminal of the control device for the variable-speed pumped-storage system, and the first terminal of the machine-side controller is the second terminal of the first terminal of the control device for the variable-speed pumped-storage system. The grid-side controller includes a grid-side converter DC voltage loop, a grid-side converter current loop, a coordinate transformation module, and a first sinusoidal pulse width modulator. The first end of the grid-side converter DC voltage loop is connected to the first end of the grid-side converter current loop. The second end of the grid-side converter current loop is connected to the first end of the first sinusoidal pulse width modulator through the coordinate transformation module. The second end of the first sinusoidal pulse width modulator is the first terminal of the first end of the grid-side controller. The machine-side controller includes a machine-side converter power loop, a machine-side converter current loop, a coordinate transformation module, and a second sinusoidal pulse width modulator. The first end of the machine-side converter power loop is connected to the first end of the machine-side converter current loop. The second end of the machine-side converter current loop is connected to the first end of the second sinusoidal pulse width modulator through the coordinate transformation module. The second end of the second sinusoidal pulse width modulator is the first terminal of the first end of the machine-side controller.

[0015] Beneficial effects: The parameter design method for a variable-speed pumped-storage system of the present invention adopts a decoupling design based on the internal model control principle, reducing the 14 PI parameters involved in the machine-side converter and grid-side converter to 7: the d-axis proportional gain and integral gain of the machine-side converter current loop PI controller, the q-axis proportional gain and integral gain of the machine-side converter current loop PI controller, the proportional gain and integral gain of the active power of the machine-side converter power loop, the proportional gain and integral gain of the reactive power of the machine-side converter power loop, the d-axis proportional gain and integral gain of the grid-side converter current loop PI controller, the q-axis proportional gain and integral gain of the grid-side converter current loop PI controller, and the proportional gain and integral gain of the grid-side DC voltage. This is further reduced to 7 bandwidths: the machine-side rotor d-axis current bandwidth. Machine-side rotor q-axis current bandwidth Active power loop bandwidth Reactive power loop bandwidth d-axis current bandwidth of the grid-side rotor , grid-side rotor q-axis current bandwidth DC voltage loop bandwidth of grid-side converter This significantly reduces the number of parameters to be tuned, lowering the complexity of tuning; it reduces the coupling effect between the generator-side converter and the grid-side converter, allowing each loop to be analyzed and tuned independently, achieving effective decoupling of each control loop and improving the design flexibility of the control system; it improves the dynamic performance and stability of the system, ensuring dynamic response performance under power generation and pumping conditions by optimizing the tuning of control parameters, and ensuring the robustness of system operation under different operating conditions; it reduces the difficulty of engineering applications, simplifying the tuning of control parameters and shortening the tuning time, which is conducive to the promotion and engineering application of variable speed pumped storage technology.

[0016] To make the above-mentioned features and advantages of the invention more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description

[0017] Figure 1 This is a structural block diagram of a variable speed pumped storage system control device according to the present invention.

[0018] Figure 2 This is a flowchart of a parameter design method for a variable-speed pumped storage system according to the present invention.

[0019] Figure 3 This is a speed diagram of the power generation condition of a variable speed pumped storage system control device according to the present invention.

[0020] Figure 4 This is a rotor current diagram under power generation conditions for a variable-speed pumped storage system control device according to the present invention.

[0021] Figure 5This is a stator power diagram showing the power generation operating conditions of a variable-speed pumped-storage system control device according to the present invention.

[0022] Figure 6 This is a DC bus voltage diagram for the power generation operation of a variable speed pumped storage system control device according to the present invention. Detailed Implementation

[0023] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] Figure 1 This is a control block diagram of a control device for a variable-speed pumped-storage system according to the present invention. In one embodiment, please refer to... Figure 1 The control device 2 for the variable-speed pumped-storage system proposed in this application is used to control the variable-speed pumped-storage system 1. The variable-speed pumped-storage system 1 includes: a main transformer T1, a magnetizing transformer T2, an inductor L, a grid-side converter 11, a turbine-side converter 12, a capacitor C, a doubly-fed induction generator 13, and a pump-turbine 14. The first end of the main transformer T1 is connected to the power grid, and the second end of the main transformer T1 is connected to the first end of the magnetizing transformer T2 and the first end of the doubly-fed induction generator 13. The second end of the magnetizing transformer T2 is connected to the first end of the inductor L, and the second end of the inductor L is connected to the power grid. The first end of the grid-side converter 11, the second end of the grid-side converter 11, and the second end of the machine-side converter 12 are all connected to the two ends of the capacitor C. The DC bus voltage across the capacitor C is Udc. The first end of the machine-side converter 12 is connected to the second end of the doubly-fed motor 13, and the third end of the doubly-fed motor 13 is connected to the first end of the pump turbine 14. The third end of the grid-side converter 11 is connected to the first terminal of the first end of the control device 2 of the variable speed pumped storage system, and the third end of the machine-side converter 12 is connected to the second terminal of the first end of the control device 2 of the variable speed pumped storage system.

[0025] Furthermore, the control device 2 of the variable speed pumped storage system includes a grid-side controller 21 and a machine-side controller 22; the first terminal of the grid-side controller 21 is the first terminal of the first terminal of the control device 2 of the variable speed pumped storage system, and the first terminal of the machine-side controller 22 is the second terminal of the first terminal of the control device 2 of the variable speed pumped storage system.

[0026] The grid-side controller 21 includes a grid-side converter DC voltage loop 211, a grid-side converter current loop 212, a coordinate transformation module 213, and a first sinusoidal pulse width modulator 214. The first end of the grid-side converter DC voltage loop 211 is connected to the first end of the grid-side converter current loop 212. The second end of the grid-side converter current loop 212 is connected to the first end of the first sinusoidal pulse width modulator 214 through the coordinate transformation module 213. The second end of the first sinusoidal pulse width modulator 214 is the first terminal of the first end of the grid-side controller 21.

[0027] The grid-side converter DC voltage loop 211 includes a grid-side converter DC voltage loop internal mode controller 2111. It takes the input bus voltage setpoint Udc* and the bus voltage Udc as inputs, calculates the grid-side rotor d-axis current setpoint igd*, and defines the transfer function of the grid-side converter DC voltage loop internal mode controller. for: , in, It is the DC voltage loop bandwidth on the grid side. It is a differential operator; ,in, It is the steady-state value of the d-axis component of the grid voltage. yes The voltage at an operating point, i.e., the steady-state value of the DC bus voltage. It is a DC bus capacitor.

[0028] The DC voltage loop 211 of the grid-side converter is used to maintain the DC bus voltage stability based on the given value Udc* of the bus voltage and the bus voltage Udc.

[0029] The grid-side converter current loop 212 includes a grid-side converter current loop internal model controller 2121 and a first decoupling module 2122, which takes into account the given value of the grid-side rotor q-axis current igq* and the grid-side rotor q-axis current igq, wherein... , The reactive power reference value is 0 when reactive power is not required, therefore igq* is generally set to 0; the given value of the grid-side rotor d-axis current igd* and the grid-side rotor d-axis current igd are input to the grid-side converter current loop inner model controller 2121, and the grid-side converter current loop inner model controller transfer function... for: , in, It is the bandwidth of the d-axis current of the grid-side rotor. It is the bandwidth of the q-axis current of the grid-side rotor. It is the grid-side rotor resistance. It is a differential operator. It is a grid-side filter inductor.

[0030] The d-axis current igd of the grid-side rotor is related to the cross-coupling term. Multiplying these values ​​and adding the q-axis output of the grid-side converter current loop internal mode controller 2121 and the grid-side rotor q-axis voltage ugq, we obtain the given value ugq* of the grid-side rotor q-axis voltage; then, we combine the grid-side rotor q-axis current igq with the cross-coupling term... Multiplying these values ​​and adding the d-axis output of the grid-side converter current loop inner mode controller 2121 and the grid-side rotor d-axis voltage ugd, we obtain the given value ugd* of the grid-side rotor d-axis voltage, where... It is the rotor angular frequency of the grid-side converter. It is a grid-side filter inductor. The first decoupling module 2122 is used to compensate or decouple the coupling in the control device, eliminate the mutual interference between the d and q axes, and allow the control of the d and q axes to be performed more independently and accurately.

[0031] The grid-side converter current loop 212 is used to control the grid-side current. After obtaining the given value ugd* of the grid-side rotor d-axis voltage and the given value ugq* of the grid-side rotor q-axis voltage, the grid-side converter 11 is controlled by the coordinate transformation module 213 and the first sinusoidal pulse width modulator 214.

[0032] The machine-side controller 22 includes a machine-side converter power loop 221, a machine-side converter current loop 222, a coordinate transformation module 223, and a second sinusoidal pulse width modulator 224. The first end of the machine-side converter power loop 221 is connected to the first end of the machine-side converter current loop 222. The second end of the machine-side converter current loop 221 is connected to the first end of the second sinusoidal pulse width modulator 224 through the coordinate transformation module 223. The second end of the second sinusoidal pulse width modulator 224 is the first terminal of the first end of the machine-side controller 22.

[0033] The machine-side converter power loop 221 includes a machine-side converter power loop internal mode controller 2211. The given value of the active power P* and the active power P are used to calculate the given value of the machine-side rotor q-axis current i. rq * The given value of reactive power Q* and the reactive power Q are used to calculate the given value of the rotor d-axis current i on the machine side. rd * Transfer function of the power loop inner mode controller of the machine-side converter for: , in, It is the bandwidth of the d-axis current of the rotor on the machine side. It is the bandwidth of the q-axis current of the rotor on the machine side. It is the active power loop bandwidth. It is the reactive power loop bandwidth. It is a differential operator.

[0034] The generator-side converter power loop 221 is used to ensure that the output power accurately tracks the grid dispatch command based on the given values ​​of active power P*, active power P, and reactive power Q* and reactive power Q.

[0035] The machine-side converter current loop 222 includes a machine-side converter current loop internal mode controller 2221 and a second decoupling module 2222, which receives the given value i of the machine-side rotor q-axis current. rq * and the q-axis current i of the rotor side rq The given value i of the input machine side rotor d-axis current rd * and the d-axis current i of the rotor on the machine side rd Transfer function of the internal model controller 2221 of the current loop of the machine-side converter. for: , in, It is the bandwidth of the d-axis current of the rotor on the machine side. It is the bandwidth of the q-axis current of the rotor on the machine side. It is a differential operator. It is the rotor resistance on the machine side. It is the leakage coefficient ,in, It is a magnetically excited inductor. It is a stator inductor. It is the rotor inductance; It is the d-axis inductance of the rotor on the machine side. It is the q-axis inductance of the rotor on the machine side.

[0036] The machine-side rotor d-axis current IRD is related to the cross-coupling term. Multiplying these values ​​and adding the q-axis output of the machine-side converter current loop inner mode controller 2221, we obtain the given value urq* of the machine-side rotor q-axis voltage. Then, we combine the machine-side rotor q-axis current irq with the cross-coupling term... Multiplying these values ​​and adding the d-axis output of the machine-side converter current loop inner mode controller 2221 yields the given value urd* of the machine-side rotor d-axis voltage, where... It is the slip angular frequency. It is the d-axis inductance of the rotor on the machine side. It is the q-axis inductance of the rotor on the machine side. The second decoupling module 2222 is used to compensate or decouple the coupling in the control device, eliminate the mutual interference between the d and q axes, and allow the control of the d and q axes to be performed more independently and accurately.

[0037] The machine-side converter current loop 222 is used to achieve rapid tracking of the excitation current and torque current, and to obtain the given value u of the machine-side rotor d-axis voltage. rd* and the given value u of the rotor q-axis voltage on the machine side. rq Then, the coordinate transformation module 223 and the second sinusoidal pulse width modulator 224 output a sinusoidal pulse width modulation signal to control the machine-side converter 12.

[0038] Figure 2 This is a flowchart illustrating a parameter design method for a variable-speed pumped-storage system according to the present invention. Please refer to [link / reference]. Figure 1 Control block diagram and Figure 2 The flowchart illustrates a parameter design method for a variable-speed pumped-storage system provided by this invention, comprising steps S1 to S4: Step S1: Determine the control object of the generator-side converter current loop. Establish the transfer function of the internal model controller of the current loop of the machine-side converter. Design the d-axis current bandwidth of the machine-side rotor. And the q-axis current bandwidth of the rotor on the machine side Complete the tuning of the current loop parameters of the machine-side converter; Step S2: Determine the control object of the power loop of the machine-side converter. Establish the transfer function of the internal model controller of the power loop of the machine-side converter. Design active power loop bandwidth and reactive power loop bandwidth Complete the power loop parameter tuning of the machine-side converter; Step S3: Determine the control object of the grid-side converter current loop. Establish the transfer function of the internal model controller of the current loop of the grid-side converter. Design the d-axis current bandwidth of the grid-side rotor. and grid-side rotor q-axis current bandwidth Complete the current loop parameter tuning of the grid-side converter; Step S4: Determine the control object of the DC voltage loop of the grid-side converter. Establish the transfer function of the DC voltage loop internal model controller for the grid-side converter. Design the DC voltage loop bandwidth on the grid side. Complete the DC voltage loop parameter tuning of the grid-side converter.

[0039] In step S1, the expression for the dq-axis voltage of the machine-side converter is: , in, It is the d-axis voltage of the rotor on the machine side. It is the q-axis voltage of the rotor on the machine side. It is the rotor resistance on the machine side. It is a differential operator. It is the d-axis inductance of the rotor on the machine side. It is the q-axis inductance of the rotor on the machine side. It is the slip angular frequency. It is the d-axis current of the rotor on the machine side. It is the q-axis current of the rotor on the machine side; It is the leakage coefficient ,in, It is a magnetically excited inductor. It is a stator inductor. It is the rotor inductance; ,in, It is the d-axis voltage variable of the rotor on the machine side. It is the q-axis voltage variable of the rotor on the machine side. It is the angular frequency of the rotor on the machine side. It is the rotor voltage on the machine side. It is the stator d-axis flux linkage. It is the stator q-axis flux linkage.

[0040] Furthermore, based on the voltage of the dq axis of the machine-side converter, the control object of the machine-side converter current loop is determined. The expression is: , in, It is the rotor resistance on the machine side. It is a differential operator. It is the q-axis inductance of the rotor on the machine side; It is the leakage coefficient ,in, It is a magnetically excited inductor. It is a stator inductor. It is the rotor inductance.

[0041] More specifically, in order to achieve complete decoupling, it should be made And a first-order filter is connected in series. To ensure the robustness of the controller, The expression is: , in, It is the rotor current bandwidth. It is a differential operator; It is a control object The estimated value.

[0042] Furthermore, the transfer function of the internal mode controller in the current loop of the machine-side converter. for: , in, It is the bandwidth of the d-axis current of the rotor on the machine side. It is the bandwidth of the q-axis current of the rotor on the machine side. It is the rotor resistance on the machine side. It is a differential operator. It is the q-axis inductance of the rotor on the machine side; It is the leakage coefficient ,in, It is a magnetically excited inductor. It is a stator inductor. It is the rotor inductance.

[0043] Furthermore, the machine-side converter current loop internal model controller designed in this invention is used to replace the PI controller of the machine-side converter current loop in the traditional variable-speed pumped-storage system, wherein... This is equivalent to the d-axis proportional gain of the PI controller in the current loop of the machine-side converter in a traditional solution. , This is equivalent to the d-axis integral gain of the PI controller in the current loop of the machine-side converter in a traditional solution. , This is equivalent to the q-axis proportional gain of the PI controller in the current loop of the machine-side converter in a traditional solution. , This is equivalent to the q-axis integral gain of the PI controller in the current loop of the machine-side converter in a traditional solution. .

[0044] Furthermore, by designing the d-axis current bandwidth of the machine-side rotor... And the q-axis current bandwidth of the rotor on the machine side Determine the transfer function of the internal model controller in the current loop of the machine-side converter. The key parameters are determined, and the current loop parameters of the machine-side converter are tuned to obtain the given value u of the machine-side rotor d-axis voltage. rd * and the given value u of the rotor q-axis voltage on the machine side. rq This ensures that the rotor current of the machine-side converter can quickly track the command, while also providing current support for the power loop control of the machine-side converter.

[0045] In step S2, the stator active power and reactive power The expression is: , in, , , It is a magnetically excited inductor. It is a stator inductor. It is the stator voltage. It is the stator angular frequency; It is the d-axis current of the rotor on the machine side. It is the q-axis current of the rotor on the machine side.

[0046] Furthermore, the control object of the power loop of the machine-side converter is determined. The expression is: , in, It is the active power loop bandwidth. It is the reactive power loop bandwidth. It is a differential operator.

[0047] Furthermore, a current regulating loop is used to realize the d-axis current on the machine side. and machine-side q-axis current reactive power on the stator side and active power The decoupling control, therefore the transfer function of the internal mode controller of the power loop of the machine-side converter. for: , in, It is a differential operator. It is the active power loop bandwidth. It is the reactive power loop bandwidth. It is the d-axis current of the rotor on the machine side. It is the q-axis current of the rotor on the machine side.

[0048] Furthermore, the machine-side converter power loop internal model controller designed in this invention is used to replace the PI controller of the machine-side converter power loop in the traditional variable-speed pumped-storage system, wherein... This is equivalent to the proportional gain value of the PI controller for the active power of the power loop in the machine-side converter in a traditional solution. This is equivalent to the integral gain of the PI controller for the active power of the power loop in the machine-side converter in a traditional solution. This is equivalent to the proportional gain value of the PI controller for the reactive power of the power loop in the machine-side converter in a traditional solution. , This is equivalent to the integral gain value of the PI controller for the reactive power of the power loop in the machine-side converter in a traditional scheme.

[0049] Furthermore, by designing the active power loop bandwidth and reactive power loop bandwidth Determine the transfer function of the internal mode controller of the power loop of the machine-side converter. The key parameters are determined to complete the power loop tuning of the machine-side converter and obtain the given value i of the machine-side rotor d-axis current. rd * and the given value i of the q-axis current of the rotor on the machine side. rq * Ensure that the stator power can accurately track the grid dispatch instructions.

[0050] In step S3, the expression for the dq-axis voltage of the grid-side converter is: , in, It is the d-axis voltage of the grid-side rotor. It is the q-axis voltage of the grid-side rotor. It is the grid-side rotor resistance. It is a differential operator. It is a grid-side filter inductor. It is the angular frequency of the grid-side rotor. It is the d-axis current of the grid-side rotor. It is the q-axis current of the grid-side rotor. It is the grid-side rotor voltage.

[0051] Furthermore, based on the voltage of the dq axis of the grid-side converter, the control object of the grid-side converter current loop is... The expression is: , in, It is the rotor resistance of the grid-side converter. It is a differential operator. It is a grid-side filter inductor.

[0052] Furthermore, the transfer function of the grid-side converter current loop internal mode controller... for: , in, It is the bandwidth of the d-axis current of the grid-side rotor. It is the bandwidth of the q-axis current of the grid-side rotor. It is a differential operator. It is a grid-side filter inductor; It is a control object The estimated value.

[0053] Furthermore, the grid-side converter current loop internal model controller designed in this invention is used to replace the PI controller of the grid-side converter current loop in the traditional variable-speed pumped-storage system, wherein... This is equivalent to the d-axis proportional gain value of the PI controller in the current loop of the grid-side converter in a traditional solution. This is equivalent to the d-axis integral gain of the PI controller in the current loop of the grid-side converter in a traditional solution. This is equivalent to the q-axis proportional gain of the PI controller in the current loop of the grid-side converter in a traditional solution. This is equivalent to the q-axis integral gain of the PI controller in the grid-side converter current loop in a traditional solution.

[0054] Furthermore, by designing the d-axis current bandwidth of the grid-side rotor... and grid-side rotor q-axis current bandwidth Determine the transfer function of the internal mode controller in the current loop of the grid-side converter. The key parameters are determined, and the current loop parameters of the grid-side converter are tuned to obtain the given values ​​of the grid-side d-axis voltage (ugd*) and the grid-side q-axis voltage (ugq*). This ensures that the rotor current of the grid-side converter can quickly track the command and provide current support for the stability of the DC bus voltage.

[0055] In step S4, the DC bus voltage The expression for the power balance equation is: , in, It is a DC bus capacitor. It is the power input to the DC bus of the rotor converter. This is the power output from the grid-side converter to the grid. Under grid voltage orientation, ,in, It is the d-axis voltage of the grid-side rotor. It is the d-axis current of the grid-side rotor.

[0056] Furthermore, at the work site Establish a linearized model: , in, It is the change in DC bus voltage. It is a variable of DC bus input power. It is a variable of the d-axis current on the grid side.

[0057] Furthermore, the control object of the DC voltage loop of the grid-side converter The expression is: , in, It is a differential operator. , It is the steady-state value of the d-axis component of the grid voltage. yes The voltage at an operating point, i.e., the steady-state value of the DC bus voltage. It is a DC bus capacitor.

[0058] Furthermore, the DC voltage loop of the grid-side converter is a first-order integrator. To match the dynamic characteristics of the DC voltage loop, a second-order filter is selected for series connection. The expression is: , in, It is the DC voltage loop bandwidth on the grid side. It is a differential operator.

[0059] Furthermore, the transfer function of the grid-side converter DC voltage loop internal mode controller... for: , in, It is the DC voltage loop bandwidth on the grid side. It is a differential operator; , It is the steady-state value of the d-axis component of the grid voltage. yes The voltage at an operating point, i.e., the steady-state value of the DC bus voltage. It is a DC bus capacitor.

[0060] Based on the principles of frequency response matching and dominant pole approximation, the transfer function of the internal mode controller in the DC voltage loop of the grid-side converter is... An approximate expression is: , in, It is the DC voltage loop bandwidth on the grid side. It is a differential operator; , It is the steady-state value of the d-axis component of the grid voltage. yes The voltage at an operating point, i.e., the steady-state value of the DC bus voltage. It is a DC bus capacitor.

[0061] Furthermore, the grid-side converter DC voltage loop internal model controller designed in this invention is used to replace the PI controller of the grid-side converter DC voltage loop in the traditional variable-speed pumped-storage system, wherein... This is equivalent to the proportional gain of the DC voltage of the grid-side converter in a traditional solution. This is equivalent to the integral gain of the DC voltage of the grid-side converter in a traditional scheme.

[0062] Furthermore, by designing the grid-side DC voltage loop bandwidth... Determine the transfer function of the DC voltage loop inner-mode controller of the grid-side converter. The key parameters are determined to complete the DC voltage loop tuning of the grid-side converter, obtain the given value igd* of the grid-side rotor q-axis current, ensure the stability of the DC bus voltage, and avoid voltage fluctuations affecting system operation.

[0063] Furthermore, the bandwidth of the d-axis current of the machine-side rotor. Machine-side rotor q-axis current bandwidth Active power loop bandwidth Reactive power loop bandwidth d-axis current bandwidth of the grid-side rotor , grid-side rotor q-axis current bandwidth Grid-side DC voltage loop bandwidth It is typically designed based on the switching frequency of the power transistors, control delay, and the dynamic requirements of the pumped storage unit.

[0064] Optionally, the machine-side rotor d-axis current bandwidth And the q-axis current bandwidth of the rotor on the machine side The frequency range is between 80Hz and 150Hz.

[0065] Optionally, the active power loop bandwidth and reactive power loop bandwidth The frequency range is between 5Hz and 20Hz.

[0066] Optionally, the d-axis current bandwidth of the grid-side rotor and grid-side rotor q-axis current bandwidth The frequency range is between 80Hz and 150Hz.

[0067] Optionally, the grid-side DC voltage loop bandwidth The range is between 10Hz and 30Hz.

[0068] Figure 3 This invention presents a speed diagram illustrating the power generation operating conditions of a variable-speed pumped-storage system control device. When the variable-speed pumped-storage system operates in power generation mode, the feasibility of parameter tuning is verified by setting different operating stages. The first operating condition is 0-10 seconds with a speed of 0.92 pu and active power of 0.97 pu; the second operating condition is 15-20 seconds with a speed of 0.98 pu and active power of 0.99 pu; the third operating condition is 25-30 seconds with a speed of 1.05 pu and active power of 1.05 pu, achieving speed changes from subsynchronous to supersynchronous. Figure 3 As shown, the rotational speed changes from subsynchronous to supersynchronous.

[0069] Figure 4 This is a rotor current diagram of the power generation operating condition of a variable-speed pumped-storage system control device according to the present invention, such as... Figure 4 As shown, under power generation conditions, the rotor current changes from 0.88 pu to 0.925 pu and then to 1.1 pu. The rotor current maintains a sinusoidal change, verifying the correctness of the rotor current loop parameter tuning of the generator-side converter.

[0070] Figure 5 This is a stator power diagram of the power generation operating conditions of a variable-speed pumped-storage system control device according to the present invention, such as... Figure 5 As shown in the stator power diagram under power generation conditions, the active power changes from 0.967 pu to 1.03 pu and then increases to 1.28 pu and remains stable, while the reactive power remains at 0, verifying the correctness of the power loop parameter tuning of the generator-side converter.

[0071] Figure 6 This is a DC bus voltage diagram of the power generation operating condition of a variable-speed pumped-storage system control device according to the present invention, such as... Figure 6 As shown, the DC bus voltage diagram under power generation conditions is maintained at 1 pu, verifying the correctness of the grid-side converter parameter settings.

[0072] This invention discloses a parameter design method for a variable-speed pumped-storage system. Employing a decoupling design based on the internal model control principle, it reduces the number of 14 PI parameters involved in the generator-side and grid-side converters—including the d-axis proportional and integral gain of the generator-side converter current loop PI controller, the q-axis proportional and integral gain of the generator-side converter current loop PI controller, the proportional and integral gain of the generator-side converter power loop active power, the proportional and integral gain of the generator-side converter power loop reactive power, the d-axis proportional and integral gain of the grid-side converter current loop PI controller, the q-axis proportional and integral gain of the grid-side converter current loop PI controller, and the proportional and integral gain of the grid-side DC voltage—to a mere 7 bandwidth: the generator-side rotor d-axis current bandwidth. Machine-side rotor q-axis current bandwidth Active power loop bandwidth Reactive power loop bandwidth d-axis current bandwidth of the grid-side rotor , grid-side rotor q-axis current bandwidth DC voltage loop bandwidth of grid-side converter This significantly reduces the number of parameters to be tuned, lowering the complexity of tuning; it reduces the coupling effect between the generator-side converter and the grid-side converter, allowing each loop to be analyzed and tuned independently, achieving effective decoupling of each control loop and improving the design flexibility of the control system; it improves the dynamic performance and stability of the system, ensuring dynamic response performance under power generation and pumping conditions by optimizing the tuning of control parameters, and ensuring the robustness of system operation under different operating conditions; it reduces the difficulty of engineering applications, simplifying the tuning of control parameters and shortening the tuning time, which is conducive to the promotion and engineering application of variable speed pumped storage technology.

[0073] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A parameter design method for a variable-speed pumped-storage system, characterized in that, include, Determine the control object of the machine-side converter current loop. Establish the transfer function of the internal model controller of the current loop of the machine-side converter. Design the d-axis current bandwidth of the machine-side rotor. And the q-axis current bandwidth of the rotor on the machine side Complete the tuning of the current loop parameters of the machine-side converter; Determine the control object of the power loop of the machine-side converter. Establish the transfer function of the internal model controller of the power loop of the machine-side converter. Design active power loop bandwidth and reactive power loop bandwidth Complete the power loop parameter tuning of the machine-side converter; Determine the control object of the grid-side converter current loop. Establish the transfer function of the internal model controller of the current loop of the grid-side converter. Design the d-axis current bandwidth of the grid-side rotor. and grid-side rotor q-axis current bandwidth Complete the current loop parameter tuning of the grid-side converter; Determine the DC voltage loop control object of the grid-side converter. Establish the transfer function of the DC voltage loop internal model controller for the grid-side converter. Design the DC voltage loop bandwidth on the grid side. Complete the DC voltage loop parameter tuning of the grid-side converter.

2. The parameter design method for a variable-speed pumped storage system as described in claim 1, characterized in that, The transfer function of the internal mode controller of the current loop of the machine-side converter is: ， in, It is the bandwidth of the d-axis current of the rotor on the machine side. It is the bandwidth of the q-axis current of the rotor on the machine side. It is a differential operator. It is the rotor resistance on the machine side. It is the leakage coefficient ,in, It is a magnetically excited inductor. It is a stator inductor. It is the rotor inductance; It is the d-axis inductance of the rotor on the machine side. It is the q-axis inductance of the rotor on the machine side.

3. The parameter design method for a variable-speed pumped storage system as described in claim 2, characterized in that, The transfer function of the power loop inner mode controller of the machine-side converter is: ， in, It is the bandwidth of the d-axis current of the rotor on the machine side. It is the bandwidth of the q-axis current of the rotor on the machine side. It is the active power loop bandwidth. It is the reactive power loop bandwidth. It is a differential operator.

4. The parameter design method for a variable-speed pumped storage system as described in claim 3, characterized in that, The transfer function of the grid-side converter current loop inner mode controller is: ， in, It is the bandwidth of the d-axis current of the grid-side rotor. It is the bandwidth of the q-axis current of the grid-side rotor. It is the grid-side rotor resistance. It is a differential operator. It is a grid-side filter inductor.

5. The parameter design method for a variable-speed pumped storage system as described in claim 4, characterized in that, The transfer function of the DC voltage loop inner mode controller of the grid-side converter is: ， in, It is the DC voltage loop bandwidth on the grid side. It is a differential operator; ,in, It is the steady-state value of the d-axis component of the grid voltage. yes The voltage at an operating point, i.e., the steady-state value of the DC bus voltage. It is a DC bus capacitor.

6. The parameter design method for a variable-speed pumped storage system as described in claim 5, characterized in that, The expression for the control object of the machine-side converter current loop is: ， in, It is the rotor resistance of the machine-side converter. It is a differential operator. It is the d-axis inductance of the rotor of the machine-side converter. It is the q-axis inductance of the rotor of the machine-side converter. It is the leakage coefficient ,in, It is a magnetically excited inductor. It is a stator inductor. It is the rotor inductance.

7. The parameter design method for a variable-speed pumped storage system as described in claim 6, characterized in that, The expression for the control object of the power loop of the machine-side converter is: ， in, It is the active power loop bandwidth. It is the reactive power loop bandwidth. It is a differential operator.

8. The parameter design method for a variable-speed pumped storage system as described in claim 7, characterized in that, The expression for the control object of the grid-side converter current loop is: ， in, It is the rotor resistance of the grid-side converter. It is a differential operator. It is a grid-side filter inductor.

9. The parameter design method for a variable-speed pumped storage system as described in claim 8, characterized in that, The expression for the control object of the DC voltage loop of the grid-side converter is: ， in, It is the change in the d-axis current on the grid side. It is the change in DC bus voltage. It is a differential operator. ,in, It is the steady-state value of the d-axis component of the grid voltage. yes The voltage at an operating point, i.e., the steady-state value of the DC bus voltage. It is a DC bus capacitor.

10. A control device for a variable-speed pumped-storage system, executing the parameter design method for a variable-speed pumped-storage system as described in any one of claims 1-9, characterized in that, It includes a grid-side controller and a machine-side controller; the first terminal of the grid-side controller is the first terminal of the first terminal of the control device of the variable speed pumped storage system, and the first terminal of the machine-side controller is the second terminal of the first terminal of the control device of the variable speed pumped storage system. The grid-side controller includes a grid-side converter DC voltage loop, a grid-side converter current loop, a coordinate transformation module, and a first sinusoidal pulse width modulator. The first end of the grid-side converter DC voltage loop is connected to the first end of the grid-side converter current loop. The second end of the grid-side converter current loop is connected to the first end of the first sinusoidal pulse width modulator through the coordinate transformation module. The second end of the first sinusoidal pulse width modulator is the first terminal of the first end of the grid-side controller. The machine-side controller includes a machine-side converter power loop, a machine-side converter current loop, a coordinate transformation module, and a second sinusoidal pulse width modulator. The first end of the machine-side converter power loop is connected to the first end of the machine-side converter current loop. The second end of the machine-side converter current loop is connected to the first end of the second sinusoidal pulse width modulator through the coordinate transformation module. The second end of the second sinusoidal pulse width modulator is the first terminal of the first end of the machine-side controller.

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