Fuzzy-pid-based coordinated control method for doubly-fed variable-speed pumped storage unit

Abstract

The application provides a double-fed variable-speed pumped storage unit cooperative control method based on a fuzzy PID, and belongs to the field of pumped storage unit control methods.The method comprises the following steps: S1, obtaining an error and an error change rate in a pumped storage unit; S2, inputting the error and the error change rate into a designed fuzzy controller to output a proportional coefficient increment and an integral coefficient increment; S3, combining an original proportional coefficient quantity and an original integral coefficient quantity of the pumped storage unit to output updated control parameters; S4, obtaining an actual water head and a theoretical water head of the pumped storage unit, dynamically adjusting a proportional coefficient gain coefficient and an integral coefficient gain quantity, and combining the updated proportional coefficient quantity of the pumped storage unit and the updated integral coefficient quantity of the pumped storage unit to jointly input into a PID controller; and S5, outputting an opening degree signal by the PID controller to an actuating mechanism, so that the actuating mechanism controls the opening degree of the variable-speed pumped storage unit.The method has high adaptability.

Description

Technical Field

[0001] This invention belongs to the technical field of control methods for variable speed pumped storage units, specifically relating to a cooperative control method for doubly-fed variable speed pumped storage units based on fuzzy PID. Background Technology

[0002] Doubly fed variable speed pumped storage units (DFHPs) are characterized by strong nonlinearity, frequent operating mode switching, and strong coupling interference between the hydro-turbine and electrical systems. In the field of pumped storage unit control methods, fuzzy control is a commonly used control method. Compared to traditional control methods that rely on precise mathematical models (such as classical PID and linear model control), it is more suitable for pumped storage units with strong nonlinearity, frequent operating mode switching (such as power generation / pumping mode switching), and strong coupling interference between the hydro-turbine and electrical systems.

[0003] However, in traditional fuzzy control methods, parameters obtained through defuzzification (such as guide vane opening and speed regulation) are usually directly used as core control parameters for pumped storage units. For example, the approach of "directly outputting the opening after defuzzification" in the "Fuzzy Adaptive Fractional-Order PID Speed ​​Regulation Method and System for Steam Turbine Generator Units" disclosed in application number 201810001261.3 is quite common in pumped storage unit control. However, when operating conditions change, this control method is prone to overshooting problems during the transition process because the preset fixed control rules cannot dynamically adapt to the "change in nonlinear characteristics" after the operating conditions change. Summary of the Invention

[0004] This invention proposes a cooperative control method for doubly fed variable speed pumped storage units based on fuzzy PID. The defuzzified output parameters are used as input parameters for PID control. The pumped storage unit is controlled through the fused control equations, which can help avoid exceeding the limits when the operating conditions change.

[0005] To achieve the above objectives, the present invention proposes the following technical content:

[0006] The collaborative control method for doubly-fed variable-speed pumped storage units based on fuzzy PID includes the following steps:

[0007] S1: Based on the control logic of the actual variable-speed pumped storage unit, obtain the mean square error of the pumped storage unit. e and error change rate ec ;

[0008] S2: The error value calculated in S1 e and error change rate ec The input is fed into a pre-designed fuzzy controller, which uses the center-of-gravity method to determine the proportional coefficient increment of the pumped storage unit's controller. and the increment of the integral coefficient ;

[0009] S3: Increment the proportional coefficient in S2 and the increment of the integral coefficient Combined with the original proportional system of pumped storage units and the original integral system number The output can affect the updated control parameters of the pumped storage unit. K P-fuz and K I-fuz ;

[0010] S4: Obtain the actual and theoretical head of the pumped storage unit, dynamically adjust the proportional gain coefficient, integral gain coefficient, and other gain values, and combine this with the updated proportional gain coefficient of the pumped storage unit. K P-fuz And the number of integral systems after the pumped storage units are updated K I-fuz These are all inputs into the PID controller;

[0011] S5: In the PID controller, the real-time proportional coefficient and the real-time integral coefficient are combined with the input difference of the PID controller. The PID controller outputs an opening signal to the actuator, and the actuator responds to the signal to control the opening of the guide vanes of the water pump turbine.

[0012] Furthermore, in step S1, according to the control logic of the pumped storage unit, there are two control scenarios:

[0013] Method 1: The actual control logic of the pumped storage unit is "speed priority"; therefore, the power setpoint issued by its system... P ref The active power value transmitted to the power grid by the sensor monitoring P real Calculate the error value e and error change rate ec The calculation formula is:

[0014]

[0015] In the formula, P ref This represents the power setpoint emitted by the system. P real This represents the active power transmitted to the power grid. t Indicates time;

[0016] Method 2: If the actual control logic of the pumped storage unit is "power priority", then it will use its system's optimal speed. n ref Real-time rotational speed of the unit rotor monitored by sensorsn real Calculate the error value e and error change rate ec The calculation formula is:

[0017]

[0018] In the formula, n ref This indicates the optimal rotational speed of the system; n real This indicates the real-time rotational speed of the unit's rotor; t Indicates time.

[0019] Since pumped storage units employ two different control logics, and the control effects differ under these two logics, this solution uses different error values ​​for each of the two different control logics. e and error change rate ec This allows for a closer approximation of real pumped storage units, a difference in control logic that exists only in the pumped storage unit field.

[0020] Furthermore, in step S3, the control parameters K P-fuz and K I-fuz The formula is:

[0021]

[0022] In the formula, This indicates the original proportional system quantity of pumped storage units; This indicates the number of original integral units for pumped storage units; Indicates the increment of the proportionality coefficient; Indicates the increment of the integral coefficient; K P-fuz This indicates the number of pumped storage units after the upgrade. K I-fuz This indicates the number of integral systems after the pumped storage unit is updated.

[0023] The original proportional coefficient values ​​are merged with the proportional coefficient increments output by the fuzzy controller, and the original integral coefficient values ​​are merged with the integral coefficient increments. While the original proportional and integral coefficient values ​​are fixed values, they are no longer fixed after incorporating the proportional and integral coefficient increments, allowing for dynamic parameter adjustment. This dynamic adjustment improves the control accuracy, response speed, and stability of the pumped storage unit.

[0024] Further, step S4 includes the following steps:

[0025] S4.1: Combine the actual head and theoretical head, and dynamically adjust the proportional gain coefficient and integral gain coefficient;

[0026] The formula is:

[0027]

[0028] In the formula, H real This indicates the measured head of the pumped storage unit; H This indicates the set head of the pumped storage unit. In the formula, H max The maximum head that indicates the stable operating range of a pumped storage unit; H min The minimum head that indicates the stable operating range of a pumped storage unit; K HP This represents the proportional gain coefficient. K HI Indicates the integral coefficient and gain coefficient; f v1 (*)and f v2 (*) all represent mapping functions;

[0029] S4.2: Calculate the number of real-time proportional coefficients and the number of real-time integral coefficients for pumped storage units;

[0030] The formula is:

[0031]

[0032] In the formula, K HP This represents the proportional gain coefficient. K HI Indicates the integral coefficient and gain coefficient; K P-fuz This indicates the number of pumped storage units after the upgrade. K I-fuz This indicates the number of integral units after the pumped storage unit has been updated; K P Indicates the real-time scale quantity; K I This indicates the number of real-time integral systems.

[0033] This incorporates the impact of head on the unit's control characteristics, and dynamically adjusts the proportional gain coefficient by combining actual and theoretical head. K HP and integral coefficient gain coefficient K HIThis allows the proportional and integral coefficients to better adapt to the unit's operating status under different heads, optimize control parameters, and make control more precise.

[0034] Furthermore, the formula for the PID controller to control the opening degree of the pumped storage unit is:

[0035]

[0036] In the formula, y ( t () indicates the operating degree of the pumped storage unit at time t; e ( t ) represents the error of the PID controller at time t. K P Indicates the real-time scale quantity; K I Indicates the number of real-time integral systems; e (t) represents the PID controller in the pumped storage unit. t Error in time.

[0037] By integrating the above series of parameters and combining them with the error of PID control, it can be applied to complex operating conditions (pumped storage units) and also take advantage of PID control (high robustness and accuracy) to maintain stable operation of the unit while precisely controlling the opening degree.

[0038] In step S2, the proportional coefficient increment and the increment of the integral coefficient The calculation formula is:

[0039]

[0040] In the formula ，w i ( e,ec ) represents the first fuzzy controller. i The output of the fuzzy rule about e and ec The weights between them; n This represents the total number of rules in the fuzzy controller; K Pi Indicates the first i The number of proportionality systems in a fuzzy rule; K Ii Indicates the first i The number of integral systems in a fuzzy rule; f 1(*) and f 2(*) represent functions related to the operating status of pumped storage units; h Indicates water head; p Indicates power.

[0041] The fuzzy controller uses the conventional parameter output of the centroid method for subsequent parameter fusion.

[0042] Furthermore, the relational expression for the mapping function is:

[0043]

[0044] In the formula, H set Indicates the defined head boundary; a 1. b 1. c 1. a 2. b 2. c 2 represents the set coefficient; x 1 and x 2 represents the corresponding variables.

[0045] The beneficial effects that can be achieved by adopting the above technologies are:

[0046] 1. In formula (2), the increment of the proportional coefficient output by the fuzzy controller is... and the increment of integral coefficients Compared with the original parameters of the unit K P0 and K I0 Combined, the updated PID core parameters are generated. K P-fuz and K I-fuz In this process, the output of fuzzy control is no longer used as a direct control parameter of the unit, but only as an input for adjustment by the PID controller. This allows fuzzy control to be suitable for situations with frequent changes in operating conditions, while the PID controller ensures the stability of control.

[0047] II. Formula (3) incorporates the measured water head. H real And set the head, dynamically generate the proportional gain coefficient K HP and integral coefficient gain coefficient K HI This avoids the parameter deviations caused by neglecting the influence of head in traditional control methods mentioned in the background technology, and can also respond to the strong coupling interference unique to pumped storage units, such as head changes.

[0048] Third, in formula (6), the output formula of traditional fuzzy PID control is mostly based on the result of fuzzy defuzzification or calculation of a single PID parameter. This scheme updates the parameters in real time according to the change of operating point, and then uses PID for precise control. Attached Figure Description

[0049] Figure 1 This is a flowchart of the method;

[0050] Figure 2 This is the logic diagram of this solution;

[0051] Figure 3 This is the mapping relationship between the water pressure suppression modules;

[0052] Figure 4 This is a comparison chart of the effects of this scheme and traditional fuzzy control under the speed-priority logic in the calculation example;

[0053] Figure 5 This is a comparison chart of the effects of this scheme and traditional fuzzy control under the power-first logic in the calculation example. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] like Figure 1 and Figure 2 As shown, the collaborative control method for a doubly-fed variable-speed pumped storage unit based on fuzzy PID includes the following steps:

[0056] S1: Based on the control logic of the actual variable-speed pumped storage unit, obtain the mean square error of the pumped storage unit. e and error change rate ec .

[0057] Specifically, pumped storage units have two control modes and two control logics, which employ different error calculation methods to better reflect actual operating conditions.

[0058] Method 1: The actual control logic of the variable speed pumped storage unit is "speed priority"; therefore, the power setpoint issued by the variable speed pumped storage unit system... P ref The active power value transmitted to the power grid by the sensor monitoring P real Calculate the error value e and error change rate ec The calculation formula is:

[0059]

[0060] In the formula, Pref This represents the power setpoint emitted by the system. P real This represents the active power transmitted to the power grid. t Indicates time; t Indicates time.

[0061] Method 2: If the actual control logic of the pumped storage unit is "power priority", then it will use its system's optimal speed. n ref Real-time rotational speed of the unit rotor monitored by sensors n real Calculate the error value e and error change rate ec The calculation formula is:

[0062]

[0063] In the formula, n ref This indicates the optimal rotational speed of the system; n real This indicates the real-time rotational speed of the unit's rotor; t Indicates time.

[0064] S2: The error value calculated in S1 e and error change rate ec The input is fed into a pre-designed fuzzy controller, which uses the center-of-gravity method to determine the proportional coefficient increment of the pumped storage unit's controller. and the increment of the integral coefficient .

[0065] Fuzzy controllers are a commonly used control method for pumped storage units, and they have the advantages of being suitable for areas with strong nonlinearity and frequent operating condition switching.

[0066] The fuzzy controller uses the centroid method to predict the increment of the proportional coefficient. and the increment of the integral coefficient The formula is:

[0067]

[0068] In equation (1), w i ( e,ec ) represents the first fuzzy controller. i The output of the fuzzy rule about e and ec The weights between them; n This represents the total number of rules in the fuzzy controller; K Pi Indicates the first i The number of proportionality systems in a fuzzy rule;K Ii Indicates the first i The number of integral systems in a fuzzy rule. f 1(*) and f 2(*) represent functions related to the operating status of pumped storage units. Indicates the increment of the proportionality coefficient; This represents the increment of the integral coefficient. h Indicates water head; p Indicates power.

[0069] S3: Increment the proportional coefficient in S2 and the increment of the integral coefficient Combined with the original proportional system of pumped storage units and the original integral system number The output can affect the updated control parameters of the pumped storage unit.

[0070] To improve the adaptability of pumped storage units to changes, the output increment of the fuzzy controller is combined with the original quantity of the fuzzy controller.

[0071] The formula is:

[0072]

[0073] In equation (2), K P0 This indicates the original proportional system quantity of pumped storage units; K I0 This indicates the number of original integral units for pumped storage units; Indicates the increment of the proportionality coefficient; Indicates the increment of the integral coefficient; K P-fuz This indicates the number of pumped storage units after the upgrade. K I-fuz This indicates the number of integral systems after the pumped storage unit is updated.

[0074] S4: Obtain the actual and theoretical head of the pumped storage unit, dynamically adjust the proportional gain coefficient, integral gain coefficient, and other gain values, and combine this with the updated proportional gain coefficient of the pumped storage unit. K P-fuz And the number of integral systems after the pumped storage units are updated K I-fuz These inputs are fed into the PID controller. This is the core design of this solution, and it includes the following steps:

[0075] S4.1: Dynamically adjust the proportional gain coefficient and integral gain coefficient.

[0076] Since existing fuzzy control systems do not consider the actual head, this scheme takes into account the difference between the actual and theoretical head, aiming to increase the control input and provide the PID controller with more comprehensive data for fusion calculation of the opening, thus making the control more accurate.

[0077] The formula is:

[0078]

[0079] In equation (3), H real This indicates the measured head of the pumped storage unit; H This indicates the set head of the pumped storage unit. In the formula, H max The maximum head that indicates the stable operating range of a pumped storage unit; H min This indicates the minimum head required for the stable operation of a pumped storage unit. K HP This represents the proportional gain coefficient. K HI Indicates the integral coefficient and gain coefficient. K HP and K HI This is the output of the water pressure suppression module. The mapping relationship for the water pressure suppression module is shown below. Figure 3 ; f v1 ( x 1) and f v2 ( x 2) Both represent mapping functions, see [link to mapping function documentation]. Figure 4 ;in:

[0080]

[0081] In equation (4), H set Indicates the defined head boundary; a 1. b 1. c 1. a 2. b 2. c 2 represents the set coefficient.

[0082] S4.2: Calculate the number of real-time proportional coefficients and the number of real-time integral coefficients for pumped storage units.

[0083] The formula is:

[0084]

[0085] In equation (5),K HP This represents the proportional gain coefficient. K HI Indicates the integral coefficient and gain coefficient; K P-fuz This indicates the number of pumped storage units after the upgrade. K I-fuz This indicates the number of integral systems after the pumped storage unit is updated. K P Indicates the real-time scale quantity; K I This indicates the number of real-time integral systems.

[0086] S5: In the PID controller, the real-time proportional coefficient and the real-time integral coefficient are combined with the input difference of the PID controller. The PID controller outputs an opening signal to the actuator, and the actuator responds to the signal to control the opening of the guide vanes of the water pump turbine.

[0087] The formula is:

[0088]

[0089] In equation (6), K P Indicates the real-time scale quantity; K I Indicates the number of real-time integral systems; e (t) represents the PID controller in the pumped storage unit. t Error in time; y ( t ) indicates pumped storage unit t The degree of openness at any given moment.

[0090] The innovation of this solution is mainly reflected in:

[0091] 1. In formula (2), the increment of the proportional coefficient output by the fuzzy controller is... and the increment of integral coefficients Compared with the original parameters of the unit K P0 and K I0 Combined, the updated PID core parameters are generated. K P-fuz and K I-fuz In this process, the output of fuzzy control is no longer used as a direct control parameter of the unit, but only as an input for adjustment by the PID controller. This allows fuzzy control to be suitable for situations with frequent changes in operating conditions, while the PID controller ensures the stability of control.

[0092] II. Formula (3) incorporates the measured water head.H real And set the head, dynamically generate the proportional gain coefficient K HP and integral coefficient gain coefficient K HI This avoids the parameter deviations caused by neglecting the influence of head in traditional control methods mentioned in the background technology, and can also respond to the strong coupling interference unique to pumped storage units, such as head changes.

[0093] Third, in formula (6), the output formula of traditional fuzzy PID control is mostly based on the result of fuzzy defuzzification or calculation of a single PID parameter. This scheme updates the parameters in real time according to the change of operating point, and then uses PID for precise control.

[0094] Calculation example:

[0095] The opening degree of a certain unit was compared by using traditional fuzzy control to directly output the opening degree and by using PID control after integrating the two schemes. The parameters of the unit are shown in Table 1.

[0096] Table 1. Relevant parameters of the unit

[0097] Parameter name numerical values <![CDATA[K P0 、K I0 ]]> 0.1、0.15 <![CDATA[H max 、H min ]]> 471m, 402m <![CDATA[n max 、n min ]]> 424.31 r / min, 398.6 r / min H 436.5m <![CDATA[a1、b1、c1]]> -3 / 5000，0，2 <![CDATA[a2、b2、c2]]> -3 / 5000，0，2 Hset 50m

[0098] The structure simulated using the parameters in Table 1 is shown below. Figure 4 and Figure 5 , Figure 4 and Figure 5 These are simulation diagrams under two different control logics (speed priority or power priority). Figure 4 This is a simulation diagram of the rotation speed priority mode; Figure 5 This is a simulation diagram under power priority.

[0099] from Figure 4 and Figure 5 As can be seen, regardless of the control logic, this scheme is superior to traditional fuzzy control in terms of stability. The stabilization speed of this scheme is fast and the amplitude is small, indicating that this scheme adopts a fusion control strategy. In the field of doubly-fed variable speed pumped storage units, it has good stability for the frequent switching conditions of doubly-fed variable speed pumped storage units.

[0100] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A cooperative control method for doubly-fed variable-speed pumped storage units based on fuzzy PID, characterized in that, Includes the following steps: S1: Based on the control logic of the actual variable-speed pumped storage unit, obtain the mean square error of the variable-speed pumped storage unit. e and error change rate ec ; S2: The error value calculated in S1 e and error change rate ec The input is fed into a pre-designed fuzzy controller, which uses the center-of-gravity method to determine the proportional coefficient increment of the pumped storage unit's controller. and the increment of the integral coefficient ; S3: Increment the proportional coefficient in S2 and the increment of the integral coefficient Combined with the original proportional system of pumped storage units and the original integral system number The output can affect the updated control parameters of the pumped storage unit. K P-fuz and K I-fuz ; S4: Obtain the actual and theoretical head of the pumped storage unit, dynamically adjust the proportional gain coefficient, integral gain coefficient, and other gain values, and combine this with the updated proportional gain coefficient of the pumped storage unit. K P-fuz And the number of integral systems after the pumped storage units are updated K I-fuz These are all inputs into the PID controller; S5: In the PID controller, the real-time proportional coefficient and the real-time integral coefficient are combined with the input difference of the PID controller. The PID controller outputs an opening signal to the actuator, and the actuator responds to the signal to control the opening of the guide vanes of the water pump turbine. In step S1, according to the control logic of the pumped storage unit, there are two control scenarios: Method 1: The actual control logic of the pumped storage unit is "speed priority"; therefore, the power setpoint issued by its system... P ref The active power value transmitted to the power grid by the sensor monitoring P real Calculate the error value e and error change rate ec The calculation formula is: ； In the formula, P ref This represents the power setpoint emitted by the system. P real This represents the active power transmitted to the power grid. t Indicates time; Method 2: If the actual control logic of the pumped storage unit is "power priority", then it will use its system's optimal speed. n ref Real-time rotational speed of the unit rotor monitored by sensors n real Calculate the error value e and error change rate ec The calculation formula is: ； In the formula, n ref This indicates the optimal rotational speed of the system; n real This indicates the real-time rotational speed of the unit's rotor; t Indicates time; Step S4 includes the following steps: S4.1: Combine the actual head and theoretical head, and dynamically adjust the proportional gain coefficient and integral gain coefficient; The formula is: ； In the formula, H real This indicates the measured head of the pumped storage unit; H This indicates the set head of the pumped storage unit. In the formula, H max The maximum head that indicates the stable operating range of a pumped storage unit; H min The minimum head that indicates the stable operating range of a pumped storage unit; K HP This represents the proportional gain coefficient. K HI Indicates the integral coefficient and gain coefficient; f v1 (*)and f v2 (*) all represent mapping functions; S4.2: Calculate the number of real-time proportional coefficients and the number of real-time integral coefficients for pumped storage units; The formula is: ； In the formula, K HP This represents the proportional gain coefficient. K HI Indicates the integral coefficient and gain coefficient; K P-fuz This indicates the number of pumped storage units after the upgrade. K I-fuz This indicates the number of integral units after the pumped storage unit has been updated; K P Indicates the real-time scale quantity; K I Indicates the number of real-time integral systems; The formula for controlling the opening degree of a pumped storage unit using a PID controller is: ； In the formula, y ( t () indicates the operating degree of the pumped storage unit at time t; e ( t ) represents the error of the PID controller at time t. K P Indicates the real-time scale quantity; K I Indicates the number of real-time integral systems; e (t) represents the PID controller in the pumped storage unit. t Error in time.

2. The cooperative control method for a doubly-fed variable-speed pumped storage unit based on fuzzy PID according to claim 1, characterized in that, In step S3, control parameters K P-fuz and K I-fuz The formula is: ； In the formula, K P0 This indicates the original proportional system quantity of pumped storage units; K I0 This indicates the number of original integral units for pumped storage units; Indicates the increment of the proportionality coefficient; Indicates the increment of the integral coefficient; K P-fuz This indicates the number of pumped storage units after the upgrade. K I-fuz This indicates the number of integral systems after the pumped storage unit is updated.

3. The method for coordinated control of a doubly-fed variable-speed pumped storage unit based on fuzzy PID according to claim 1, characterized in that, In step S2, the proportional coefficient increment and the increment of the integral coefficient The calculation formula is: ； In the formula ，w i ( e,ec ) represents the first fuzzy controller. i The output of the fuzzy rule about e and ec The weights between them; n This represents the total number of rules in the fuzzy controller; K Pi Indicates the first i The number of proportionality systems in a fuzzy rule; K Ii Indicates the first i The number of integral systems in a fuzzy rule; f 1(*) and f 2(*) represent functions related to the operating status of pumped storage units; h Indicates water head; p Indicates power.

4. The method for coordinated control of a doubly-fed variable-speed pumped storage unit based on fuzzy PID according to claim 1, characterized in that, The relational expression for the mapping function is: ； In the formula, H set Indicates the defined head boundary; a 1. b 1. c 1. a 2. b 2. c 2 represents the set coefficient; x 1 and x 2 represents the corresponding variables.

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