A voltage amplitude feedback system based on direct-axis current fuzzy control output limiting

Abstract

The application provides a voltage amplitude feedback system based on direct-axis current fuzzy control output limiting, which is provided with fuzzy logic controller optimization design, field weakening control strategy optimization selection and dynamic limiting strategy; the fuzzy logic controller optimization design accurately reflects complex dynamic relationship by constructing a fuzzy rule system based on original motor input rotating speed and output direct-axis current expected value mapping, and adopting open-loop experimental data to optimize membership function and fuzzy rule; the field weakening control strategy optimization selection adopts a field weakening control strategy based on voltage amplitude feedback, preferentially guarantees direct-axis current output, and prevents output overvoltage from damaging subsequent components such as load; and the dynamic limiting strategy implementation ensures that the direct-axis current output based on voltage amplitude feedback has sufficient fluctuation bandwidth when the input rotating speed is gently inputted, and builds a system to verify the strategy feasibility.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of permanent magnet motor system monitoring, and particularly relates to a voltage amplitude feedback system based on output amplitude limiting of direct-axis current fuzzy control. BACKGROUND

[0002] Most traditional permanent magnet synchronous generator control strategies only rely on voltage feedback to regulate direct-axis current, ignoring the influence of input speed variation on system dynamic performance, which leads to difficulty in maintaining stability of the system when facing complex working conditions such as sudden speed change; in order to overcome this limitation, the applicant takes the prime mover speed as the core reference variable for direct-axis current regulation according to requirements; specifically, the system calculates the expected value of the direct-axis current through a fuzzy logic controller according to the real-time input prime mover speed; the expected value is then used as the reference for direct-axis current regulation in the voltage amplitude feedback mechanism, and fine regulation is performed in combination with a dynamic amplitude limiting strategy; in order to ensure that the permanent magnet synchronous generator can maintain the stability of the output voltage when the speed changes smoothly, the applicant also designs a bandwidth control logic; the logic optimizes the electromagnetic characteristics of the generator through accurate regulation of the direct-axis current, so that the direct-axis current output by the voltage amplitude feedback can closely track the rated value, thereby ensuring the continuous stability of the system performance; in the face of extreme working conditions of sudden input speed change, the traditional voltage amplitude feedback mechanism may not be able to adjust the direct-axis current in time due to insufficient response speed, resulting in output voltage fluctuation; therefore, in the system proposed by the applicant, the direct-axis current output by the fuzzy controller is set as the upper and lower boundaries of the amplitude limiting to cope with such emergency situations; in the moment of sudden speed fluctuation, the fuzzy controller can quickly evaluate the current working condition, calculate the appropriate direct-axis current value, and ensure that the generator can respond immediately through the amplitude limiting mechanism, effectively suppressing the transient fluctuation of the output voltage, and significantly improving the robustness of the permanent magnet synchronous generator under different working conditions and the stability of the output voltage. SUMMARY

[0003] To solve the above technical problems, the application provides a voltage amplitude feedback system based on output amplitude limiting of direct-axis current fuzzy control, which is designed by setting a fuzzy logic controller, optimizing a field weakening control strategy and implementing a dynamic amplitude limiting strategy; the fuzzy logic controller is designed by constructing a fuzzy rule system based on mapping of the input speed of the prime mover and the expected value of the output direct-axis current, optimizing the membership function and fuzzy rules by using open-loop experimental data, and accurately reflecting the complex dynamic relationship; the field weakening control strategy is optimized by using a field weakening control strategy based on voltage amplitude feedback, which prioritizes the output of the direct-axis current to prevent damage to subsequent components such as loads caused by overvoltage; the dynamic amplitude limiting strategy is implemented by accurately setting the amplitude limiting bandwidth to ensure that the direct-axis current output based on voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is smooth, and the strategy is verified to be feasible by building a system.

[0004] To achieve the above object, the technical scheme adopted by the present application is:

[0005] The voltage amplitude feedback system based on the output limiting of direct-axis current fuzzy control is characterized in that: the voltage amplitude feedback system based on the output limiting of direct-axis current fuzzy control is provided with a fuzzy logic controller optimization design, a field weakening control strategy optimization selection and a dynamic limiting strategy; the fuzzy logic controller optimization design constructs a fuzzy rule system based on the mapping of the input speed of a prime mover and the expected value of the output direct-axis current, optimizes the membership function and the fuzzy rule through open-loop experimental data, and ensures accurate reflection of the complex dynamic relationship; the field weakening control strategy optimization selection adopts a field weakening control strategy based on voltage amplitude feedback, preferentially ensures the output of the direct-axis current, prevents the damage of the output overvoltage to the subsequent components such as the load, directly obtains the direct-axis current by comparing the stator voltage reference value with the voltage limit value, and realizes safe and reliable regulation by introducing a current limiting link; the dynamic limiting strategy implementation ensures that the direct-axis current output based on the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is gently input, can quickly respond when the input speed is sharply fluctuated, and builds a system to verify the feasibility of the strategy.

[0006] Further, the fuzzy logic controller optimization design of the voltage amplitude feedback system based on the output limiting of direct-axis current fuzzy control is realized through the fuzzy rule system construction and the controller performance verification and iterative optimization; in the fuzzy rule system construction, the input variable is the input speed of the prime mover, and the output variable is the expected value of the direct-axis current; this setting is based on accurate system analysis, aiming to realize the dynamic matching of the input speed and the expected value of the direct-axis current; a series of open-loop experiments are conducted, the maximum stable speed of the generator that can be reached under different direct-axis current setting conditions is recorded and analyzed, a perfect fuzzy rule system is constructed combining with the experimental data, accurate mapping from the input speed to the expected value of the direct-axis current is realized, and the membership function and the fuzzy rule are optimized to ensure that the controller can accurately capture and reflect the complex dynamic relationship between the input speed and the direct-axis current.

[0007] Further, the flux-weakening control strategy of the voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control is realized through a control strategy optimization and a control strategy implementation mechanism. The control strategy optimization realizes the priority of ensuring appropriate direct-axis current output when the current amplitude is too large by controlling the direct-axis and quadrature-axis currents, thereby ensuring that the subsequent load is not damaged due to overvoltage. The control strategy implementation mechanism is based on the flux-weakening control strategy of the voltage amplitude feedback, and the direct-axis current is directly obtained by comparing the stator voltage reference value with the voltage limit value. When the space vector pulse width modulation is used, the voltage limit value is designed as 1 / 3 of the DC bus voltage reference value. In addition, the current limiting link is introduced to limit the quadrature-axis current, thereby ensuring that the current amplitude is always less than the maximum current amplitude limit, and thus the precise adjustment of the generator flux-weakening control is realized.

[0008] Further, the dynamic limiting strategy of the voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control is realized through limiting bandwidth setting and experimental verification and performance evaluation. The limiting bandwidth setting scientifically sets the upper and lower boundaries of the limiting according to the direct-axis current value output by the fuzzy controller. Through step-by-step experimental verification, the limiting bandwidth that can ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is gentle and can timely adjust the direct-axis current when the input speed fluctuates sharply to realize rapid response is selected. The experimental verification and performance evaluation verify the feasibility of the voltage amplitude dynamic feedback flux-weakening voltage stabilization strategy of the direct-axis current fuzzy control limiting through simulation experiments under different working conditions and comparison of the performance of different control systems. The system has the stability of the voltage amplitude feedback flux-weakening strategy under stable working conditions, and exhibits the robustness of the speed input fuzzy control flux-weakening strategy under extreme working conditions, thereby providing solid technical support for the stable operation of the permanent magnet synchronous generator in the renewable energy power generation field.

[0009] Further, the steps of the optimized design of the fuzzy logic controller of the voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control are as follows:

[0010] Step 1: Fuzzy controller design. Different direct-axis current values are input under various load conditions, and the maximum voltage stabilization speed corresponding to each direct-axis current value is systematically recorded. According to the analysis results of the experimental data, the membership function and fuzzy rules are designed to ensure that the fuzzy controller can intelligently and accurately output reasonable direct-axis current values according to the input speed information.

[0011] Step two, the optimization of the field-weakening control strategy; the preferred strategy is realized through the control strategy optimization and control strategy implementation mechanism; the preferred strategy ensures the appropriate direct-axis current output by controlling the direct-axis and quadrature-axis currents when the current amplitude is too large; the implementation mechanism is a field-weakening control strategy based on voltage amplitude feedback, which directly obtains the direct-axis current by comparing the stator voltage reference value with the voltage limit value; at the same time, the current limiting link is introduced to limit the quadrature-axis current, so as to realize the accurate adjustment of the generator field-weakening control;

[0012] Step three, dynamic limiting strategy; the limiting bandwidth setting and experimental verification and performance evaluation are realized; the upper and lower boundaries of the limiting amplitude are set according to the direct-axis current value output by the fuzzy controller, the limiting bandwidth is selected to ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth, and the direct-axis current is adjusted in time to realize fast response; the feasibility of the voltage amplitude dynamic feedback field-weakening voltage stabilization strategy of the direct-axis current fuzzy control limiting amplitude is verified through simulation experiments under different working conditions, and the stability and robustness of the system under different working conditions are verified.

[0013] Further, the dynamic limiting strategy of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting amplitude is a fuzzy control limiting amplitude voltage amplitude dynamic feedback field-weakening voltage stabilization system; the bandwidth limitation can be expressed as:

[0014]

[0015] Wherein: i dup , i dlow is the upper and lower limits of the limiting amplitude;

[0016] i d1 is the direct-axis current regulated by the input speed;

[0017] Δi d1 is the set bandwidth.

[0018] The application brings the following benefits:

[0019] 1. The voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting amplitude calculates the expected value of the direct-axis current according to the real-time input of the prime mover speed through the fuzzy logic controller; this expected value is then used as the reference for the direct-axis current adjustment in the voltage amplitude feedback mechanism, and is finely regulated in combination with the dynamic limiting strategy; in order to ensure that the permanent magnet synchronous generator can maintain the stability of the output voltage when the speed changes smoothly;

[0020] 2. The voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting amplitude controls the direct-axis current accurately through the bandwidth control logic, optimizes the electromagnetic characteristics of the generator, so that the direct-axis current output by the voltage amplitude feedback can closely track the rated value, thereby ensuring the continuous stability of the system performance;

[0021] 3. The voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control outputs the direct-axis current set by the fuzzy controller as the upper and lower boundaries of the limiting, and in the moment of sharp fluctuation of the input speed, the fuzzy controller can quickly evaluate the current working condition, calculate the appropriate direct-axis current value, and ensure that the generator can immediately respond through the limiting mechanism, effectively suppress the transient fluctuation of the output voltage, and significantly improve the robustness of the permanent magnet synchronous generator under different working conditions and the stability of the output voltage. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structural block diagram of the weak magnetic voltage stabilizing system based on the voltage amplitude feedback.

[0023] Figure 2 It is a structural block diagram of the weak magnetic voltage stabilizing system based on the output limiting of the direct-axis current fuzzy control.

[0024] Figure 3 It is an experimental result of the weak magnetic voltage stabilizing system based on the output limiting of the direct-axis current fuzzy control under the experimental condition of smooth rising of the input speed.

[0025] Figure 4 It is an experimental result of the weak magnetic voltage stabilizing system based on the output limiting of the direct-axis current fuzzy control under the experimental condition of sudden change of the input speed. DETAILED DESCRIPTION

[0026] The application will be described in further detail below in combination with the drawings and specific embodiments:

[0027] The voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control is shown, the voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control is provided with fuzzy logic controller optimization design, weak magnetic control strategy optimization selection, and dynamic limiting strategy; the fuzzy logic controller optimization design constructs a fuzzy rule system based on the mapping of the input speed of the prime mover and the expected value of the output direct-axis current, optimizes the membership function and the fuzzy rule through open-loop experimental data, and ensures accurate reflection of the complex dynamic relationship; the weak magnetic control strategy optimization selection adopts the weak magnetic control strategy based on the voltage amplitude feedback, preferentially ensures the output of the direct-axis current, prevents damage to the subsequent components such as the load caused by the output overvoltage, directly obtains the direct-axis current by comparing the stator voltage reference value with the voltage limit value, and realizes safe and reliable adjustment by introducing the current limiting link; the dynamic limiting strategy implements by accurately setting the limiting bandwidth, ensures that the direct-axis current output based on the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is gently input, can quickly respond when the input speed is sharply fluctuated, and builds the system to verify the feasibility of the strategy.

[0028] The application will be described below taking the parameters of the permanent magnet synchronous motor in Table 1 as an example.

[0029] Table 1 Permanent magnet synchronous motor parameter table

[0030]

[0031]

[0032] The fuzzy logic controller of the voltage amplitude feedback system based on the direct-axis current fuzzy control output amplitude limiting is optimized by fuzzy rule system construction and controller performance verification and iterative optimization. In the construction of the fuzzy rule system, the input variable is the input speed of the prime mover, and the output variable is the direct-axis current expected value. This setting is based on accurate system analysis, aiming to achieve dynamic matching of the input speed and the direct-axis current expected value. Through a series of open-loop experiments, the maximum stable speed of the generator under different direct-axis current settings is recorded and analyzed. Combined with experimental data, a perfect fuzzy rule system is constructed to achieve accurate mapping from input speed to direct-axis current expected value. At the same time, the membership function and fuzzy rules are optimized to ensure that the controller can accurately capture and reflect the complex dynamic relationship between input speed and direct-axis current.

[0033] The nonlinear characteristics of the motor, especially saturation and hysteresis effect, significantly complicate the relationship between direct-axis current and magnetic flux, hindering the establishment of an accurate mathematical model of direct-axis current and maximum voltage-stabilized speed. To address this challenge, the invention introduces a fuzzy control strategy. The design of the fuzzy logic controller takes the real-time input speed of the prime mover as the input variable and the expected value of the direct-axis current as the output variable. The goal is to quickly respond to changes in input speed and optimize the field weakening control strategy by accurately regulating the direct-axis current, thereby improving the stability of the output voltage and the overall robustness of the system, and enhancing the overall performance of the generator.

[0034] To construct an effective fuzzy rule system, a series of open-loop experiments were conducted. During the test, the maximum stable speed of the generator under different direct-axis current settings was recorded under different load conditions. Combined with these experimental data and professional knowledge in the field of motor control, detailed fuzzy rules were developed to achieve accurate mapping from input speed to direct-axis current expected value. In addition, the membership function and fuzzy rules were deeply optimized to ensure that the controller can accurately capture and reflect the complex dynamic relationship between input speed and direct-axis current, thereby improving the performance of the controller.

[0035] The fuzzy controller has the ability to quickly respond to changes in the input speed of the prime mover, ensuring that the output voltage remains stable when the input speed of the prime mover suddenly changes. However, to ensure the stability of the output voltage, the reference value of the direct-axis current may be slightly higher, resulting in some degree of waste. In addition, the system may also have poor regulation effect under different load conditions.

[0036] The weak excitation control strategy of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is realized by the control strategy optimization and the control strategy implementation mechanism; the control strategy optimization realizes the priority guarantee of the appropriate direct-axis current output when the current amplitude is too large by controlling the direct-axis and quadrature-axis currents, and ensures that the subsequent load will not be damaged due to overvoltage; due to the particularity of the generator weak excitation control technology, the system has obvious advantages in the independent regulation of the direct-axis and quadrature-axis currents, realizes the priority guarantee of the appropriate direct-axis current output when the current amplitude is too large, ensures that the subsequent load will not be damaged due to overvoltage, and greatly enhances the robustness and safety of the system; the core of the system is to realize the accurate separation control of the quadrature-axis current (i q ) and the direct-axis current (i d ); when the stator current reference value (i s ) exceeds the preset safety threshold, the system will immediately activate the limiting mechanism to dynamically limit i q , and ensure that i s is always maintained below the maximum allowed current (I max ); in this process, the priority of the direct-axis current (i d ) is strictly guaranteed, and even if i q needs to be reduced to meet the current limiting condition, the output of i d can remain stable and undisturbed; this feature enables the generator to maintain effective weak excitation control by flexibly regulating i d when facing abnormal voltage rise, and even if i q drops to zero, the system can still maintain a stable operating state; most importantly, when the DC bus voltage returns to normal, the voltage outer loop control module can quickly respond to recalculate and output reasonable quadrature-axis current reference value (i q * ), ensuring that the generator can operate continuously, efficiently and stably;

[0037] The control strategy implementation mechanism is based on the weak excitation control strategy of the voltage amplitude feedback, and the direct-axis current is directly obtained by comparing the stator voltage reference value with the voltage limit value; when using space vector pulse width modulation, the voltage limit value is designed as 1 / 3 of the DC bus voltage reference value; in addition, by introducing a current limiting link, the quadrature-axis current is limited to ensure that the current amplitude is always less than the maximum current amplitude limit, thereby realizing accurate regulation of the generator weak excitation control; the benefit of this control strategy is that a regulation system for the direct-axis current (i d ) is constructed by using a PI controller combined with a voltage amplitude feedback mechanism, and the system block diagram is shown in Figure 1 ; under this system, the direct-axis current reference value (i d* )Instead of following the traditional voltage loop calculation approach, a more direct and efficient determination method is adopted; it is directly derived by comparing the preset reference value of stator voltage with a preset voltage limit value, and the advantage of this strategy is particularly prominent in the context of space vector pulse width modulation technology; usually the voltage limit value in space vector pulse width modulation technology is accurately set as a certain fixed proportion of the direct current bus voltage reference value to ensure the stability and efficiency of the system; by comparing the preset reference value of stator voltage with the set voltage limit value, the system can quickly and accurately calculate the direct axis current reference value required for field weakening control (i d * ); this strategy not only simplifies the calculation process, but also significantly improves the response speed and regulation accuracy of the system; under complex working conditions such as voltage fluctuation or load variation, the system can quickly adjust the direct axis current to maintain stable field weakening control state; at the same time, since the voltage amplitude feedback is directly used for calculation, this strategy significantly enhances the sensitivity and adaptability of the system to voltage changes, thereby further improving the overall system performance; the control strategy realizes the rapid and accurate calculation of the direct axis current reference value required for field weakening control; in the context of SVPWM technology, this strategy provides a solid support for the stable operation and performance optimization of the generator.

[0038] From the perspective of control theory, the sudden change of prime mover input speed has an important influence on the dynamic performance of the system; however, the traditional field weakening voltage stabilization control system based on voltage amplitude feedback is difficult to quickly and accurately adjust its control strategy to cope with such sudden changes in the absence of speed information; therefore, in order to improve the stability of the system and the smoothness of the output voltage, it is necessary to consider the input speed of the prime mover as a key input parameter in future system optimization, which will help to enhance the adaptability and response speed of the system to speed mutation, thereby further improving the overall performance of the system.

[0039] The dynamic limiting strategy of the voltage amplitude feedback system based on the output limiting of direct axis current fuzzy control is realized through limiting bandwidth setting and experimental verification and performance evaluation; the limiting bandwidth setting is scientifically set according to the direct axis current value output by the fuzzy controller; through step-by-step experimental verification, the limiting bandwidth is selected which can not only ensure that the direct axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is smooth, but also can adjust the direct axis current in time to realize rapid response when the input speed fluctuates sharply; in order to fuse the adaptability of the field weakening voltage stabilization system based on input speed regulation in the speed mutation scene and the robustness of the field weakening voltage stabilization system based on voltage amplitude feedback in the smooth speed condition, an innovative voltage amplitude dynamic feedback field weakening voltage stabilization system with direct axis current fuzzy control limiting is proposed, and the system block diagram is shown in Figure 2 ; its bandwidth limitation can be expressed as:

[0040]

[0041] wherein: i dup , i dlow is the upper and lower limit of the amplitude limiting;

[0042] i d1 is the direct-axis current regulated by the input speed;

[0043] Δi d1 is the set bandwidth;

[0044] The core strategy of the system is to use a fuzzy controller to dynamically generate a reference value for the direct-axis current based on the real-time input speed, and then to implement precise amplitude limiting control on the direct-axis current obtained by the voltage amplitude feedback link. In the stable running stage of the system, the amplitude limiting range set by the fuzzy controller allows the direct-axis current output based on the voltage amplitude feedback to freely fluctuate within a reasonable range, thereby ensuring the efficient operation and necessary flexibility of the system. Once the input speed changes significantly, the fuzzy controller can quickly respond by dynamically adjusting the amplitude limiting boundaries, so that the direct-axis current responds quickly to achieve immediate optimization and stability of the motor performance. To ensure the scientificity of the amplitude limiting boundaries, an experimental verification process needs to be used. Through parameter tuning and performance evaluation, an optimal amplitude limiting bandwidth is determined.

[0045] In order to comprehensively and deeply evaluate the performance of the voltage amplitude feedback field weakening and voltage stabilization model based on the fuzzy control output amplitude limiting of the direct-axis current, two experimental system conditions with typical significance are introduced: the original input speed steady rise scenario and the input speed sudden change scenario. These designs aim to simulate various working conditions that may be encountered in the actual operation environment of the generator, to ensure that the controller can exhibit good stability and adaptability under various complex conditions.

[0046] 1) Original input speed steady rise experimental condition:

[0047] This experimental condition is specifically set as follows: the initial speed is set to 0 revolutions per minute, the speed increase is set to 5000 revolutions per minute per second, and the final speed is stabilized at 8000 revolutions per minute. This setting aims to simulate the entire process of gradually accelerating the generator from a stationary state to the rated speed. By implementing this experiment, the precise control ability of the field weakening and voltage stabilization system on the output voltage and power stability during the steady rise of the speed can be observed in detail. At the same time, this experiment can also effectively evaluate the response speed and robustness of the controller within a wide speed range.

[0048] 2) Original input speed sudden change experimental condition

[0049] In order to accurately simulate the sudden change of speed that may be encountered in the actual operation of the generator, the experimental conditions are set as follows: the initial speed is set to 5000 revolutions per minute, and at the time node of 1 second, the speed suddenly increases to 8000 revolutions per minute; this setting aims to strictly test the instantaneous response speed and stability of the field weakening voltage stabilization system when facing sudden speed changes;

[0050] These two experimental conditions fully consider the various possible working conditions of the generator in actual operation, aiming to provide a comprehensive and in-depth perspective for the performance evaluation of the voltage amplitude feedback field weakening voltage stabilization model based on the output limiting of the direct-axis current fuzzy control; By implementing these experiments, detailed performance data of the controller under different speed conditions can be obtained, providing solid data support for subsequent optimization and improvement work; At the same time, these experimental results will provide important technical reference for the stable operation and energy efficiency improvement of the generator;

[0051] The experimental verification and performance evaluation are carried out by simulating experiments under different working conditions, comparing the performance of different control systems, and verifying the feasibility of the voltage amplitude dynamic feedback field weakening voltage stabilization strategy based on the output limiting of the direct-axis current fuzzy control; The system has the stability of the voltage amplitude feedback field weakening strategy under stable working conditions, and the robustness of the fuzzy control field weakening strategy with speed input under extreme working conditions, providing solid technical support for the stable operation of the permanent magnet synchronous generator in the field of renewable energy power generation; After a series of detailed test experiments, the performance of the control system is analyzed under different working conditions, and the effectiveness and advancement of the field weakening voltage stabilization system combining the output limiting of the direct-axis current fuzzy control and the voltage amplitude dynamic feedback are tested, which can maintain the output voltage within a small range of 5.1V under the condition of sudden change of the input speed of the prime mover Figure 3 The test results show that the system exhibits stability and robustness of the output voltage in a wide speed range; This result shows that the system can maintain efficient and stable operation under stable working conditions, providing a solid performance foundation for complex and variable environments in practical applications;

[0052] Under the condition of sudden change of the input speed of the prime mover Figure 4 The test results show that the system also exhibits excellent performance; When facing the challenge of sudden speed change, the system exhibits equal voltage stability; Especially when the speed changes dramatically, the fluctuation amplitude of the output voltage is strictly controlled within a very small range, and the maximum voltage difference is accurately limited within 5.1V; This outstanding performance not only reflects the robustness of the strategy under extreme conditions, but also proves that it can flexibly cope with various uncertain factors to ensure the sustained stable operation of the system

[0053] The steps of the fuzzy logic controller optimization design based on the output limiting of the direct-axis current fuzzy control and the voltage amplitude feedback system are as follows:

[0054] Step one, fuzzy controller design; in various load conditions, input different direct axis current values, and systematically record the corresponding maximum steady voltage speed, and design membership function and fuzzy rules according to the analysis results of experimental data, to ensure that the fuzzy controller can intelligently and accurately output reasonable direct axis current value according to the input speed information.

[0055] Step two, optimization selection of field weakening control strategy; control strategy optimization and control strategy implementation mechanism are realized; the optimization strategy ensures appropriate direct axis current output by controlling the direct and quadrature axis currents when the current amplitude is too large; the implementation mechanism is a field weakening control strategy based on voltage amplitude feedback, which directly obtains the direct axis current by comparing the stator voltage reference value with the voltage limit value; at the same time, a current limiting link is introduced to limit the quadrature axis current, realizing accurate adjustment of the generator field weakening control;

[0056] Step three, dynamic limiting strategy; realized by limiting bandwidth setting and experimental verification and performance evaluation; the upper and lower boundaries of the limiting amplitude are set according to the direct axis current value output by the fuzzy controller, and the limiting bandwidth is selected to ensure that the direct axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth, and the direct axis current can be adjusted in time to realize fast response; through simulation experiments under different working conditions, the feasibility of the voltage amplitude dynamic feedback field weakening voltage stabilization strategy of the direct axis current fuzzy control limiting amplitude is verified, as well as the stability and robustness of the system under different working conditions.

[0057] In summary, the voltage amplitude feedback system based on direct axis current fuzzy control output limiting amplitude has the same stability as the voltage amplitude feedback field weakening strategy under stable working conditions, and exhibits the same robustness as the speed input fuzzy control field weakening strategy under extreme working conditions; this innovative design provides strong technical support for the stable operation of permanent magnet synchronous generators in the field of renewable energy power generation, and brings new breakthroughs to the technical innovation in the field of motor control.

[0058] The above is only a preferred embodiment of the present application, and does not limit the present application in any other form, and any modification or equivalent change made according to the technical essence of the present application still falls within the scope of the present application.

Claims

1. A voltage magnitude feedback system based on direct axis current fuzzy control output limiting, characterized by: The voltage amplitude feedback system based on the output limiting of direct-axis current fuzzy control is provided with fuzzy logic controller optimization design, field weakening control strategy optimization selection and dynamic limiting strategy; The fuzzy logic controller optimization design constructs a fuzzy rule system based on the mapping of prime mover input speed and output direct-axis current expected value, optimizes membership function and fuzzy rule through open-loop experimental data, and ensures accurate reflection of complex dynamic relationship; The field weakening control strategy optimization selection adopts field weakening control strategy based on voltage amplitude feedback, preferentially ensures direct-axis current output, prevents output overvoltage from damaging subsequent components of the load, directly obtains direct-axis current by comparing stator voltage reference value and voltage limit value, and realizes safe and reliable regulation by introducing current limiting link; the dynamic limiting strategy ensures sufficient fluctuation bandwidth of direct-axis current output based on voltage amplitude feedback when input speed is gently input, and enables quick response when input speed fluctuates sharply, and the strategy feasibility is verified by building a system; The step of fuzzy logic controller optimization design of the voltage amplitude feedback system based on the output limiting of direct-axis current fuzzy control is specifically as follows: Step one, fuzzy controller design; under various load conditions, different direct-axis current values are input, and the maximum steady voltage speed corresponding thereto is recorded systematically, and membership function and fuzzy rule are designed according to the analysis result of experimental data, so as to ensure that the fuzzy controller can intelligently and accurately output reasonable direct-axis current value according to the input speed information; Step two, field weakening control strategy optimization selection; the optimization selection is realized through control strategy optimization and control strategy implementation mechanism; the optimization strategy ensures appropriate direct-axis current output by controlling the direct-axis current and the quadrature-axis current respectively when the current amplitude is too large; The implementation mechanism is a field weakening control strategy based on voltage amplitude feedback, which directly obtains direct-axis current by comparing stator voltage reference value and voltage limit value; at the same time, a current limiting link is introduced to limit the quadrature-axis current, so as to realize accurate regulation of generator field weakening control; Step three, dynamic limiting strategy; the strategy is realized through limiting bandwidth setting and experimental verification and performance evaluation; the upper and lower boundaries of limiting are set according to the direct-axis current value output by the fuzzy controller, the limiting bandwidth is selected which can ensure sufficient fluctuation bandwidth of direct-axis current output based on voltage amplitude feedback and timely adjust direct-axis current to realize quick response; the feasibility of the voltage amplitude dynamic feedback field weakening voltage stabilization strategy of the direct-axis current fuzzy control limiting is verified through simulation experiment under different working conditions, and the stability and robustness of the system under different working conditions are verified; The limiting bandwidth setting of the dynamic limiting strategy of the voltage amplitude feedback system based on the output limiting of direct-axis current fuzzy control is a fuzzy control limiting voltage amplitude dynamic feedback field weakening voltage stabilization system; The bandwidth limitation can be expressed as: ； wherein: , are the upper and lower clipping limits; is the direct axis current regulated by the input speed; To set bandwidth.

2. The voltage magnitude feedback system based on direct axis current fuzzy control output limiting according to claim 1, wherein: The fuzzy logic controller of the voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control is optimized by fuzzy rule system construction and controller performance verification and iterative optimization; in the fuzzy rule system construction, the input variable is the prime mover input speed, and the output variable is the direct-axis current expected value; this setting is based on accurate system analysis, aiming to realize dynamic matching of the input speed and the direct-axis current expected value; and through a series of open-loop experiments, the maximum stable speed that the generator can reach under different direct-axis current setting conditions is recorded and analyzed; combined with experimental data, a perfect fuzzy rule system is constructed to realize accurate mapping from the input speed to the direct-axis current expected value; at the same time, the membership function and the fuzzy rule are optimized to ensure that the controller can accurately capture and reflect the complex dynamic relationship between the input speed and the direct-axis current.

3. The voltage magnitude feedback system based on direct axis current fuzzy control output limiting according to claim 1, wherein: The field weakening control strategy optimization of the voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control is realized by control strategy optimization and control strategy implementation mechanism; the control strategy optimization realizes the priority of ensuring appropriate direct-axis current output when the current amplitude is too large by controlling the direct-axis and quadrature-axis currents respectively, and ensures that the subsequent load will not be damaged due to overvoltage; the control strategy implementation mechanism is based on the field weakening control strategy of the voltage amplitude feedback, and the direct-axis current is directly obtained by comparing the stator voltage reference value with the voltage limit value; when using space vector pulse width modulation, the voltage limit value is designed as 1 / 3 of the DC bus voltage reference value; in addition, by introducing a current limiting link, the quadrature-axis current is limited to ensure that the current amplitude is always less than the maximum current amplitude limit, thereby realizing accurate adjustment of the generator field weakening control.

4. The voltage magnitude feedback system based on direct axis current fuzzy control output limiting according to claim 1, wherein: The dynamic limiting strategy of the voltage amplitude feedback system based on the output limiting of the direct-axis current fuzzy control is realized by limiting bandwidth setting and experimental verification and performance evaluation; the limiting bandwidth setting scientifically sets the upper and lower boundaries of the limiting according to the direct-axis current value output by the fuzzy controller; through step-by-step experimental verification, a limiting bandwidth is selected that can ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is gentle, and can adjust the direct-axis current in time when the input speed fluctuates sharply to realize fast response; The experimental verification and performance evaluation verify the feasibility of the voltage amplitude dynamic feedback field weakening and voltage stabilization strategy of the direct-axis current fuzzy control limiting by comparing the performance of different control systems through simulation experiments under different working conditions; the system has the stability of the voltage amplitude feedback field weakening strategy under stable working conditions, and shows the robustness of the speed input fuzzy control field weakening strategy under extreme working conditions, providing solid technical support for the stable operation of the permanent magnet synchronous generator in the field of renewable energy power generation.

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