A Second-Order Desired PID Control Method for Primary Frequency Regulation of Gas Turbine

Abstract

This invention discloses a second-order desired PID control method for primary frequency regulation of gas turbines. It addresses the challenges in primary frequency regulation control of gas turbines, including the coupling between the fuel control loop and the speed control loop, resulting in slow tracking speed. Conventional PI control strategies often fail to achieve satisfactory control performance, while advanced control strategies require significant computation, hindering large-scale engineering applications. This invention replaces the traditional PI controller in the primary frequency regulation control scheme with a second-order desired PID controller, optimizing the traditional PI control strategy in terms of both controller structure and parameter tuning. A parameter tuning process that is easy to implement and highly engineering-compliant is proposed. Applying the second-order desired PID control strategy to the primary frequency regulation system of a gas turbine ensures rapid response while exhibiting smaller overshoot, significantly improving the primary frequency regulation performance of the gas turbine unit.

Description

Technical Field

[0001] This invention belongs to the field of energy power and automatic control technology, and relates to a second-order desired PID control method for primary frequency regulation of a gas turbine. Background Technology

[0002] Due to its advantages such as fast response, high efficiency, and cleanliness, gas turbine units have become a key component in my country's construction of a new energy system. To cope with load fluctuations and frequency volatility caused by the large-scale grid integration of new energy sources such as wind and solar power, gas turbine units require strong primary frequency regulation capabilities, which is crucial for the safe operation and frequency stability of the power grid. Gas turbine units play a central role in clean energy supply and the construction of integrated energy systems, and the quality of their primary frequency regulation has a significant impact on the frequency control of the large power grid. However, the primary frequency regulation control of gas turbines faces challenges such as the coupling effect between the fuel control loop and the speed control loop, and slow tracking speed.

[0003] To further enhance the primary frequency regulation capability of gas turbine units, researchers have conducted extensive studies on control strategy design and control logic optimization. For example, by optimizing the speed control mode of the main control system, reducing the frequency regulation dead zone, and increasing the frequency regulation amplitude, a significant improvement in the unit's primary frequency regulation response speed has been achieved. The response speed to primary frequency regulation commands has been improved by adding blocking logic and modifying the frequency difference signal. Furthermore, to address the issue of the primary frequency regulation response index failing to meet grid requirements, optimization logic based on feedforward limiting and power closed-loop compensation has been proposed to enhance the primary frequency regulation capability.

[0004] The actual control logic for primary frequency regulation of gas turbines is mostly based on proportional-integral (PI) control strategies. This is because PI controllers have advantages such as simple structure, excellent performance, easy implementation, and clear parameter meanings. To further improve the primary frequency regulation capability of gas turbines, domestic scholars have proposed a control strategy based on Active Disturbance Rejection Control (ADRC). This strategy optimizes ADRC parameters using a multi-objective genetic algorithm to enhance the primary frequency regulation capability of the gas turbine. In addition, control strategies based on neural networks have also been studied in gas turbine primary frequency regulation systems. However, due to the large computational load required for advanced control strategies, engineering implementation presents certain challenges, and large-scale engineering applications remain difficult given the current computing power of gas turbine control platforms. Summary of the Invention

[0005] To address the problems and shortcomings of the existing technologies, this invention proposes a second-order desired PID control method for primary frequency regulation of gas turbines, which optimizes the traditional gas turbine control strategy from both the aspects of controller structure and parameter tuning.

[0006] A second-order desired PID control method for primary frequency regulation of a gas turbine is proposed. This method replaces the PI controller in the traditional primary frequency regulation control scheme of the gas turbine with a second-order desired PID controller. The parameter stability domain of the second-order desired PID controller is obtained based on the D-segmentation method, and a controller parameter tuning process that is easy to implement and has strong engineering feasibility is derived.

[0007] A second-order desired PID control method for primary frequency regulation of a gas turbine is proposed, which replaces the PI controller in the traditional primary frequency regulation control scheme of the gas turbine with a second-order desired PID controller. The desired second-order output model is defined as follows:

[0008]

[0009] In the formula, y is the controlled variable, h1 and h0 are the first and zeroth order coefficients of the second-order expectation model, respectively, and r is the setpoint. Let be the second derivative of y. Let y be the first derivative (similar operators will not be repeated below).

[0010] The extended disturbance observer for the controlled system is designed using the following formula:

[0011]

[0012] In the formula, This represents the observer's observations of the expanded state, where k and ξ are the gain (adjustable parameter) and intermediate variable of the expanded perturbation observer, respectively, l is an adjustable parameter, u is the control input, and z2 is the [value of the observer]. State estimation.

[0013] The formula for calculating the second-order desired PID controller is as follows:

[0014]

[0015] In the formula, e is the deviation between the set value and the controlled quantity, i.e., e = ry.

[0016] Based on the parameter stability region of the second-order desired PID controller, a controller parameter tuning procedure that is easy to implement and has strong engineering feasibility is derived. The specific adjustable parameter tuning procedure is as follows:

[0017] (1) Based on the control performance requirements, first determine the expected dynamic equation. The coefficient, for example, based on the expected adjustment time t. sd We can obtain h0∈[2~6] / t sd h1 = 2h0;

[0018] (2) Choose the larger l and k∈[3~10]h0;

[0019] (3) Decrease l until a satisfactory control effect is achieved;

[0020] (4) If satisfactory control effect cannot be achieved, increase h0 appropriately and repeat steps (2) and (3).

[0021] Beneficial effects

[0022] This invention proposes a PID control method for primary frequency regulation of gas turbines, designing a second-order desired proportional-integral-derivative (PID) control strategy. The traditional PI controller in the primary frequency regulation control scheme of gas turbines is replaced with a second-order desired PID controller. The traditional PI control strategy is optimized in terms of both controller structure and parameter tuning. Based on the derivation of the controller parameter stability domain, an easy-to-implement and highly engineering-compliant parameter tuning process is proposed. Applying the second-order desired PID control strategy to the primary frequency regulation system of gas turbines can significantly improve the primary frequency regulation performance of gas turbine units while ensuring fast response and smaller overshoot. Attached Figure Description

[0023] Figure 1 A schematic diagram of a proposed second-order desired PID control method for primary frequency regulation of a gas turbine is shown. The second-order desired PID1 is a speed controller, and the second-order desired PID2 is a fuel controller.

[0024] Figure 2 A schematic diagram of the PI control structure of a traditional gas turbine primary frequency control scheme, where PI1 is the speed controller and PI2 is the fuel controller. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0026] To address the problems and shortcomings of the existing technologies, this invention proposes a second-order expected PID control method for primary frequency regulation of gas turbines. This method optimizes the traditional gas turbine control strategy from both the controller structure and parameter tuning aspects. The gas turbine primary frequency regulation expected dynamic PI control method includes the following aspects:

[0027] 1. A second-order desired PID control method for primary frequency regulation of a gas turbine, which replaces the PI controller in the traditional primary frequency regulation control scheme of the gas turbine with a second-order desired PID controller, such as... Figure 1 As shown, traditional control schemes are as follows Figure 2As shown, the parameter stability domain of the second-order desired PID controller is obtained based on the D-segmentation method, and a controller parameter tuning process that is easy to implement and has strong engineering feasibility is derived.

[0028] 2. A second-order desired PID control method for primary frequency regulation of a gas turbine, which replaces the PI controller in the traditional primary frequency regulation control scheme of the gas turbine with a second-order desired PID controller. The desired second-order output model is defined as follows:

[0029]

[0030] In the formula, y is the controlled variable, h1 and h0 are the first and zeroth order coefficients of the second-order expectation model, respectively, and r is the setpoint. Let be the second derivative of y. Let y be the first derivative (similar operators will not be repeated below).

[0031] The extended disturbance observer for the controlled system is designed using the following formula:

[0032]

[0033] In the formula, This represents the observer's observations of the expanded state, where k and ξ are the gain (adjustable parameter) and intermediate variable of the expanded perturbation observer, respectively, l is an adjustable parameter, u is the control input, and z2 is the [value of the observer]. State estimation.

[0034] The formula for calculating the second-order desired PID controller is as follows:

[0035]

[0036] In the formula, e is the deviation between the set value and the controlled quantity, i.e., e = ry.

[0037] 3. Based on the parameter stability region of the second-order desired PID controller, a controller parameter tuning procedure that is easy to implement and has strong engineering feasibility is derived. The specific adjustable parameter tuning procedure is as follows:

[0038] (1) Based on the control performance requirements, first determine the expected dynamic equation. The coefficient, for example, based on the expected adjustment time t. sd We can obtain h0∈[2~6] / t sd h1 = 2h0;

[0039] (2) Choose the larger l and k∈[3~10]h0;

[0040] (3) Decrease l until a satisfactory control effect is achieved;

[0041] (4) If satisfactory control effect cannot be achieved, increase h0 appropriately and repeat steps (2) and (3).

[0042] The above embodiments are only for more clearly illustrating the present invention, and are not intended to limit the present invention. Those skilled in the art can make various changes and adjustments without departing from the spirit and scope of the present invention, and the resulting technical solutions also fall within the protection scope of the present invention.

Claims

1. A second-order desired PID control method for primary frequency regulation of a gas turbine, characterized in that, The PI controller of the traditional primary frequency control scheme for gas turbines is replaced by a second-order desired PID controller. The stability domain of the second-order desired PID controller is obtained based on the D-segmentation method, and a controller parameter tuning process that is easy to implement and highly engineering-friendly is derived. The specific adjustable parameter tuning process is as follows: (1) Based on the control performance requirements, first determine the expected dynamic equation. In the formula, y is the controlled variable, h1 and h0 are the first and zeroth order coefficients of the second-order expectation model, respectively, and r is the setpoint. Let be the second derivative of y. Let be the first derivative of y; based on the expected settling time t. sd We obtain h0∈[2~6] / t sd h1 = 2h0, where h1 and h0 are the first-order and zero-order coefficients of the second-order expectation model, respectively; (2) Choose larger l and k∈[3~10]h0, where l is an adjustable parameter, k is the gain of the extended perturbation observer, and h0 is the zero-order coefficient of the second-order expectation model; (3) Decrease l until a satisfactory control effect is achieved; (4) If satisfactory control effect cannot be achieved, increase h0 appropriately and repeat steps (2) and (3).

2. The second-order desired PID control method for primary frequency regulation of a gas turbine as described in claim 1, characterized in that, Replacing the PI controller in the traditional primary frequency control scheme of the gas turbine with a second-order expected PID controller, the expected dynamic equation is: In the formula, y is the controlled variable, h1 and h0 are the first and zeroth order coefficients of the second-order expectation model, respectively, and r is the setpoint. Let be the second derivative of y. The first derivative of y; The extended disturbance observer for the controlled system is designed using the following formula: In the formula, This represents the observer's observations of the expanded state, where k and ξ are the gain and intermediate variable of the expanded perturbation observer, respectively, l is an adjustable parameter, u is the control input, and z2 is the [value of the observer]. State estimation; The formula for calculating the second-order desired PID controller is as follows: In the formula, e is the deviation between the set value and the controlled quantity, i.e., e = ry.

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