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

Abstract

The invention provides a voltage amplitude feedback system based on direct-axis current fuzzy control output amplitude limiting. The system is provided with fuzzy logic controller optimization design, field weakening control strategy optimization selection and a dynamic amplitude limiting strategy. According to the fuzzy logic controller optimization design, a fuzzy rule system based on prime mover input rotating speed and output direct-axis current expected value mapping is constructed, a membership function and a fuzzy rule are optimized through open-loop experimental data, and a complex dynamic relation is accurately reflected; a field weakening control strategy based on voltage amplitude feedback is adopted in field weakening control strategy optimization selection, direct-axis current output is guaranteed preferentially, and output overvoltage is prevented from damaging follow-up components such as loads; according to the implementation of the dynamic amplitude limiting strategy, the amplitude limiting bandwidth is accurately set, it is ensured that the direct-axis current output based on voltage amplitude feedback has enough fluctuation bandwidth when the input rotating speed is gently input, and a system is built to verify the feasibility of the strategy.

Description

Technical Field

[0001] The invention relates to the technical field of permanent magnet motor system monitoring, in particular to a voltage amplitude feedback system based on direct-axis current fuzzy control output limiting. Background Art

[0002] Most traditional permanent magnet synchronous generator control strategies rely solely on voltage feedback to regulate the direct-axis current, ignoring the impact of input speed changes on the system's dynamic performance. This makes it difficult for the system to maintain stability when faced with complex operating conditions such as sudden speed changes. To overcome this limitation, the applicant uses the prime mover speed as the core reference variable for direct-axis current regulation based on demand. Specifically, the system uses a fuzzy logic controller to calculate the expected value of the direct-axis current based on the real-time input prime mover speed. This expected value is then used as a benchmark for direct-axis current regulation in the voltage amplitude feedback mechanism, and is finely regulated in combination with a dynamic limiting strategy. In order to ensure that the permanent magnet synchronous generator can maintain output voltage stability when the speed changes steadily, the applicant has also designed a set of bandwidth control logic. This logic achieves this by precisely controlling the direct-axis current. Regulation 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; however, in the face of extreme working conditions where the input speed changes sharply, 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 fluctuations; for this reason, in the system proposed by the applicant, the direct-axis current output by the fuzzy controller is set to the upper and lower boundaries of the limit to cope with such emergency situations; at the moment of sharp fluctuations in speed, the fuzzy controller can quickly evaluate the current operating conditions, calculate the appropriate direct-axis current value, and ensure that the generator can respond immediately through the limit mechanism, effectively suppressing transient fluctuations in 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 of the invention

[0003] In order to solve the above technical problems, the present invention proposes a voltage amplitude feedback system based on direct-axis current fuzzy control output limiting, by setting fuzzy logic controller optimization design, weak-field 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 prime mover input speed and the output direct-axis current expected value, and uses open-loop experimental data to optimize the membership function and fuzzy rules to accurately reflect the complex dynamic relationship; the weak-field control strategy optimization selection adopts a weak-field control strategy based on voltage amplitude feedback to give priority to the direct-axis current output and prevent the output overvoltage from damaging the subsequent components such as the load; the dynamic limiting strategy is implemented by accurately setting the limiting bandwidth to ensure that the direct-axis current output based on the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is smoothly input, and the system is built to verify the feasibility of the strategy.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A voltage amplitude feedback system based on direct-axis current fuzzy control output limiting is characterized in that: the voltage amplitude feedback system based on direct-axis current fuzzy control output limiting 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 prime mover input speed and output direct-axis current expected value, optimizes membership functions and fuzzy rules through open-loop experimental data, and ensures accurate reflection of complex dynamic relationships; the weak magnetic control strategy optimization selection adopts a weak magnetic control strategy based on voltage amplitude feedback, gives priority to direct-axis current output, prevents output overvoltage from damaging subsequent components such as loads, and directly obtains the direct-axis current by comparing the stator voltage reference value with the voltage limit value, and introduces a current limiting link to achieve safe and reliable regulation; the dynamic limiting strategy is implemented by accurately setting the limiting bandwidth to ensure that the direct-axis current output based on the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is smoothly input, and can respond quickly when the input speed fluctuates violently, and a system is built to verify the feasibility of the strategy.

[0006] Furthermore, the optimization design of the fuzzy logic controller of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is achieved through the construction of a fuzzy rule system and the verification and iterative optimization of the controller performance; in the construction of the fuzzy rule system, it is firstly clarified that 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 precise system analysis, aiming to achieve dynamic matching of the input speed and the expected value of the direct-axis current; 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 the experimental data, a complete fuzzy rule system is constructed to achieve accurate mapping from input speed to expected value of direct-axis current; 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.

[0007] Furthermore, the optimization selection of the weak-field control strategy of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is achieved through the control strategy optimization and control strategy implementation mechanism; the control strategy optimization achieves the priority of ensuring appropriate direct-axis current output when the current amplitude is too large by controlling the AC and DC axis currents respectively, thereby ensuring that the subsequent load will not be damaged by overvoltage; the control strategy implementation mechanism is based on the weak-field control strategy of 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 to be 1 / 3 of the DC bus voltage reference value; in addition, by introducing a current limiting link, the AC axis current is limited to ensure that the current amplitude is always less than the maximum current amplitude limit, thereby achieving precise adjustment of the weak-field control of the generator.

[0008] Furthermore, the dynamic limiting strategy of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is realized through limiting bandwidth setting, 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 not only ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is slow, but also can adjust the direct-axis current in time when the input speed fluctuates violently to achieve a fast response; the experimental verification and performance evaluation conduct simulation experiments under different working conditions, compare the performance of different control systems, and verify the feasibility of the voltage amplitude dynamic feedback weak magnetic voltage stabilization strategy of the direct-axis current fuzzy control limiting; the system has the stability of the voltage amplitude feedback weak magnetic strategy under stable working conditions, and at the same time exhibits the robustness of the fuzzy control weak magnetic strategy with speed as input under extreme working conditions, providing solid technical support for the stable operation of permanent magnet synchronous generators in the field of renewable energy power generation.

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

[0010] Step 1: Design of fuzzy controller: Under various load conditions, input different direct-axis current values, and systematically record the corresponding maximum voltage-stabilizing speed. Based on the analysis results of the experimental data, design the membership function and fuzzy rules to ensure that the fuzzy controller can intelligently and accurately output reasonable direct-axis current values ​​based on the input speed information.

[0011] Step 2: Optimize and select the weak magnetic control strategy; realize it through the control strategy optimization and control strategy implementation mechanism; the optimization strategy controls the AC and DC axis currents respectively to ensure that the appropriate DC axis current output is given priority when the current amplitude is too large; the implementation mechanism is based on the weak magnetic control strategy of voltage amplitude feedback, and the DC axis current is directly obtained 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 AC axis current to achieve precise adjustment of the generator weak magnetic control;

[0012] Step three, dynamic limiting strategy; achieved through limiting bandwidth setting and experimental verification and performance evaluation; set the upper and lower boundaries of the limit according to the direct-axis current value output by the fuzzy controller, and select a limiting bandwidth that can ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth and can adjust the direct-axis current in time to achieve rapid response; through simulation experiments under different working conditions, verify the feasibility of the voltage amplitude dynamic feedback weak magnetic stabilization strategy of the direct-axis current fuzzy control limiting, as well as the stability and robustness of the system under different working conditions.

[0013] Furthermore, the voltage amplitude dynamic feedback weak magnetic voltage stabilization system with fuzzy control limiting of the voltage amplitude feedback system with dynamic limiting strategy based on the direct axis current fuzzy control output limiting is set; its bandwidth limitation can be expressed as:

[0014]

[0015] Where: i dup 、i dlow The upper and lower limits are:

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

[0017] Δi d1 To set the bandwidth.

[0018] The benefits of this application are:

[0019] 1. The voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting calculates the expected value of the direct-axis current according to the real-time input prime mover speed through the fuzzy logic controller; this expected value is then used as the benchmark for direct-axis current regulation 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 steadily;

[0020] 2. The voltage amplitude feedback system based on the direct-axis current fuzzy control output limiter optimizes the electromagnetic characteristics of the generator by setting the bandwidth control logic to precisely control 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;

[0021] 3. The voltage amplitude feedback system based on direct-axis current fuzzy control output limiting sets the direct-axis current output by the fuzzy controller as the upper and lower boundaries of the limiting. At the moment when the speed fluctuates sharply, the fuzzy controller can quickly evaluate the current operating conditions, calculate the appropriate direct-axis current value, and ensure that the generator can respond immediately through the limiting mechanism, effectively suppressing the transient fluctuations of the output voltage, and significantly improving the robustness of the permanent magnet synchronous generator under different operating conditions and the stability of the output voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural block diagram of a weak magnetic field voltage stabilization system based on voltage amplitude feedback;

[0023] Figure 2 It is the structural block diagram of the voltage amplitude feedback weak magnetic field voltage stabilization system based on direct axis current fuzzy control output limiting;

[0024] Figure 3 The experimental results of the voltage amplitude feedback weak magnetic field voltage stabilization system based on direct axis current fuzzy control output limiting under the experimental condition of input speed rising steadily.

[0025] Figure 4 The experimental results of the voltage amplitude feedback weak magnetic voltage stabilization system based on direct-axis current fuzzy control output limitation under the experimental conditions of sudden input speed change. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0027] A voltage amplitude feedback system based on direct-axis current fuzzy control output limiting is shown. The voltage amplitude feedback system based on direct-axis current fuzzy control output limiting 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 prime mover input speed and output direct-axis current expected value, optimizes membership functions and fuzzy rules through open-loop experimental data, and ensures accurate reflection of complex dynamic relationships; the weak magnetic control strategy optimization selection adopts a weak magnetic control strategy based on voltage amplitude feedback, gives priority to direct-axis current output, prevents output overvoltage from damaging subsequent components such as loads, and directly obtains the direct-axis current by comparing the stator voltage reference value with the voltage limit value, and introduces a current limiting link to achieve safe and reliable regulation; the dynamic limiting strategy is implemented by accurately setting the limiting bandwidth to ensure that the direct-axis current output based on the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is smoothly input, and can respond quickly when the input speed fluctuates violently, and a system is built to verify the feasibility of the strategy.

[0028] The present invention is described by taking the parameters of the permanent magnet synchronous motor in Table 1 as an example.

[0029] Table 1 Permanent magnet synchronous motor parameters

[0030]

[0031]

[0032] The fuzzy logic controller optimization design of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is realized through the construction of the fuzzy rule system, the controller performance verification and iterative optimization; in the construction of the fuzzy rule system, it is firstly clarified that 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 precise system analysis, aiming to achieve dynamic matching between the input speed and the expected value of the direct-axis current; 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 the experimental data, a complete fuzzy rule system is constructed to achieve accurate mapping from input speed to expected value of direct-axis current; 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 shown, especially the saturation and hysteresis effects, significantly complicate the relationship between the direct-axis current and the magnetic flux, and hinder the establishment of an accurate mathematical model of the direct-axis current and the maximum voltage-regulated speed. To meet this challenge, the invention introduces a fuzzy control strategy. The design of the fuzzy logic controller uses 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. It aims to quickly respond to changes in the input speed, optimize the weak magnetic control strategy by accurately regulating the direct-axis current, and thus improve the stability of the output voltage and the overall robustness of the system, thereby comprehensively enhancing the comprehensive performance of the generator.

[0034] In order to build an effective fuzzy rule system, a series of open-loop experiments were carried out. During the test, the maximum stable speed of the generator under different load conditions and different direct-axis current settings were recorded. Combining these experimental data with professional knowledge in the field of motor control, detailed fuzzy rules were formulated to achieve accurate mapping of input speed to expected direct-axis current 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 shown has the ability to respond quickly to changes in the input speed of the prime mover, and can ensure that the output voltage remains stable when the input speed of the prime mover changes suddenly; however, in order to ensure the stability of the output voltage, the reference value of the direct-axis current may be slightly higher, resulting in a certain degree of waste; in addition, facing different load conditions, the system may also have the problem of poor control effect;

[0036] The optimization selection of the weak magnetic control strategy of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is realized through the control strategy optimization and control strategy implementation mechanism; the control strategy optimization is realized by controlling the AC and DC axis currents respectively, so as to give priority to ensuring the appropriate direct axis current output when the current amplitude is too large, and ensure that the subsequent load will not be damaged by overvoltage; in view of the particularity of the generator weak magnetic control technology, this system shows significant advantages in the independent regulation of the AC and DC axis currents, and realizes the priority to ensure the appropriate direct axis current output when the current amplitude is too large, and ensure that the subsequent load will not be damaged by overvoltage, which greatly enhances the robustness and safety of the system; the core of the system is to realize the quadrature axis current (i q ) and the direct axis current (i d ) precise separation control; when the stator current reference value (i s ) exceeds the preset safety threshold, the system will immediately activate the limit mechanism to q Implement dynamic constraints to ensure i s Always maintain the maximum allowable current (I max ) below; in this process, the direct axis current (i d ) is strictly guaranteed, even in i q If the current limit condition needs to be reduced, i d The output can also remain stable and undisturbed; this feature allows the generator to flexibly adjust the voltage when faced with abnormal voltage increases. d To maintain effective field weakening control, even if i q Even if the DC bus voltage drops to zero, the system can maintain a stable operating state; more importantly, when the DC bus voltage returns to normal, the voltage outer loop control module can respond quickly, recalculate and output a reasonable quadrature-axis current reference value (i q * ) to ensure that the generator can operate continuously, efficiently and stably;

[0037] The control strategy implementation mechanism shown is based on the weakening magnetic control strategy of voltage amplitude feedback. 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 to be 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 achieving precise regulation of the generator's weakening magnetic control. The benefit of this control strategy is that a PI controller is used in combination with a voltage amplitude feedback mechanism to construct a control strategy for the direct-axis current (i d ) control system, the system block diagram is as follows Figure 1 As shown in the figure; Under this system, the direct-axis current reference value (i d* ) does not follow the traditional voltage loop calculation method, but adopts a more direct and efficient determination method; it is directly derived by comparing the preset reference value of the stator voltage with a preset voltage limit value. In the scenario of using space vector pulse width modulation technology, the advantage of this strategy is particularly prominent; usually the voltage limit value in space vector pulse width modulation technology is accurately set to a fixed ratio of the DC bus voltage reference value to ensure the stability and efficiency of the system; by comparing the preset reference value of the stator voltage with the set voltage limit value, the system can quickly and accurately calculate the direct-axis current reference value (i d * ); This strategy not only simplifies the calculation process, but also significantly improves the response speed and control accuracy of the system; under complex conditions such as voltage fluctuations or load changes, the system can adjust the direct-axis current more quickly to maintain a stable weak-field control state; at the same time, since the voltage amplitude feedback is directly used for calculation, the strategy significantly enhances the system's sensitivity and adaptability to voltage changes, thereby further improving the overall system performance; this control strategy realizes the fast and accurate calculation of the direct-axis current reference value required for weak-field control; in the context of SVPWM technology, this strategy provides solid support for the stable operation and performance optimization of the generator.

[0038] From the perspective of control theory, the sudden change of the prime mover input speed has an important impact on the dynamic performance of the system; however, the traditional weak magnetic voltage stabilization control system based on voltage amplitude feedback is difficult to quickly and accurately adjust its control strategy to cope with such a sudden change 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 prime mover input speed as a key input parameter in future system optimization, which will help enhance the system's adaptability and response speed to sudden changes in speed, thereby further improving the overall performance of the system.

[0039] The dynamic limiting strategy of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is realized through limiting bandwidth setting, experimental verification and performance evaluation. The limiting bandwidth setting is scientifically set according to the direct-axis current value output by the fuzzy controller, and the upper and lower boundaries of the limiting are set; through step-by-step experimental verification, the limiting bandwidth is selected to ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is slow, and the direct-axis current can be adjusted in time when the input speed fluctuates violently to achieve a fast response. In order to integrate the adaptability of the weak magnetic voltage stabilization system based on input speed control in the speed mutation scenario and the robustness of the weak magnetic voltage stabilization system based on voltage amplitude feedback under stable speed conditions, an innovative voltage amplitude dynamic feedback weak magnetic voltage stabilization system with direct-axis current fuzzy control limiting is proposed. The system block diagram is shown in the figure. Figure 2 As shown; its bandwidth limitation can be expressed as:

[0040]

[0041] Where: i dup 、i dlow The upper and lower limits are:

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

[0043] Δi d1 To set the bandwidth;

[0044] The core strategy of this system is to use a fuzzy controller to dynamically generate a reference value of the direct-axis current based on the real-time input speed, and then implement precise limiting control on the direct-axis current obtained by the voltage amplitude feedback link; in the stable operation stage of the system, the limiting range set by the fuzzy controller allows the direct-axis current output based on the voltage amplitude feedback to fluctuate freely 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 respond quickly, and by dynamically adjusting the limiting boundary, the direct-axis current can respond quickly, thereby achieving instant optimization and stabilization of the motor performance; in order to ensure the scientific nature of the limiting boundary, an experimental verification process is required; through parameter tuning and performance evaluation, the aim is to determine an optimal limiting bandwidth.

[0045] In order to comprehensively and deeply evaluate the performance of the voltage amplitude feedback weak magnetic voltage stabilization model based on the direct-axis current fuzzy control output limit, two typical experimental system conditions are introduced: the prime mover input speed steady increase scenario and the input speed sudden change scenario; these designs are intended to simulate various working conditions that may be encountered in the actual operating environment of the generator, so as to ensure that the controller can show good stability and adaptability in various complex situations;

[0046] 1) Experimental conditions for steady increase of prime mover input speed:

[0047] The experimental conditions are specifically set as follows: the starting speed is set to 0 rpm, the speed increase is set to 5000 rpm per second, and the final speed is stabilized at 8000 rpm. This setting is intended to simulate the entire process of the generator gradually accelerating from a stationary state to the rated speed. By implementing this experiment, the precise control capability of the weak magnetic voltage stabilization system on the output voltage and power stability during the steady increase in speed can be carefully observed. At the same time, this experiment can also effectively evaluate the response speed and robust performance of the controller in a wide speed range.

[0048] 2) Experimental conditions for sudden change of input speed of prime mover

[0049] In order to accurately simulate the speed mutation that the generator may encounter in actual operation, the experimental conditions are set as follows: the starting speed is set to 5000 rpm, and at the time node of 1 second, the speed suddenly increases to 8000 rpm; this setting is intended to strictly test the instant response speed and stability of the weak magnetic voltage stabilization system when facing a speed mutation;

[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 weak magnetic voltage stabilization model based on direct-axis current fuzzy control output limiting; 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 also provide important technical references for the stable operation and energy efficiency improvement of the generator;

[0051] The experimental verification and performance evaluation shown in the figure verify the feasibility of the voltage amplitude dynamic feedback weak magnetic voltage stabilization strategy with direct-axis current fuzzy control limiting by conducting simulation experiments under different working conditions and comparing the performance of different control systems. The system has the stability of the voltage amplitude feedback weak magnetic voltage stabilization strategy under stable working conditions, and at the same time, it shows the robustness of the fuzzy control weak magnetic voltage strategy with speed as input under extreme working conditions, which provides solid technical support for the stable operation of permanent magnet synchronous generators in the field of renewable energy power generation. After a series of meticulous test experiments, the performance of the control system is analyzed under different working conditions, and the effectiveness and advancement of the weak magnetic voltage stabilization system with direct-axis current fuzzy control limiting combined with voltage amplitude dynamic feedback is verified. Under the condition of sudden change in the input speed of the prime mover, the system can be used to Figure 3 The test results show that the system exhibits stability and robustness of 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 changing environments in practical applications;

[0052] Under the condition of sudden change of input speed of the prime mover, Figure 4 The test results show that the system also shows excellent performance; when dealing with the challenges brought by sudden changes in speed, the system shows the same voltage stability ability; especially when the speed changes drastically, the fluctuation range of the output voltage is strictly controlled within a very small range, and the maximum voltage difference is precisely limited to within 5.1V; this outstanding performance not only reflects the robustness of the strategy under extreme conditions, but also proves that it can flexibly deal with various uncertain factors to ensure the continuous and stable operation of the system.

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

[0054] Step 1: Design of fuzzy controller: Under various load conditions, input different direct-axis current values, and systematically record the corresponding maximum voltage-stabilizing speed. Based on the analysis results of the experimental data, design the membership function and fuzzy rules to ensure that the fuzzy controller can intelligently and accurately output reasonable direct-axis current values ​​based on the input speed information.

[0055] Step 2: Optimize and select the weak magnetic control strategy; realize it through the control strategy optimization and control strategy implementation mechanism; the optimization strategy controls the AC and DC axis currents respectively to ensure that the appropriate DC axis current output is given priority when the current amplitude is too large; the implementation mechanism is based on the weak magnetic control strategy of voltage amplitude feedback, and the DC axis current is directly obtained 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 AC axis current to achieve precise adjustment of the generator weak magnetic control;

[0056] Step three, dynamic limiting strategy; achieved through limiting bandwidth setting and experimental verification and performance evaluation; set the upper and lower boundaries of the limit according to the direct-axis current value output by the fuzzy controller, and select a limiting bandwidth that can ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth and can adjust the direct-axis current in time to achieve rapid response; through simulation experiments under different working conditions, verify the feasibility of the voltage amplitude dynamic feedback weak magnetic stabilization strategy of the direct-axis current fuzzy control limiting, 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 has the same stability as the voltage amplitude feedback weakening strategy under stable working conditions, and shows the same robustness as the fuzzy control weakening strategy based on speed input 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 also brings new breakthroughs to technological innovation in the field of motor control.

[0058] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A voltage amplitude feedback system based on direct axis current fuzzy control output limiting, characterized in that: The voltage amplitude feedback system based on direct-axis current fuzzy control output limiting 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 between the input speed of the prime mover and the expected value of the output direct-axis current, and optimizes the membership function and fuzzy rules through open-loop experimental data to ensure accurate reflection of complex dynamic relationships; The described weak-field control strategy optimization chooses to adopt a weak-field control strategy based on voltage amplitude feedback, which gives priority to ensuring the direct-axis current output to prevent output overvoltage from damaging subsequent components such as the load, and 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 achieve safe and reliable regulation; the described dynamic limiting strategy is implemented by accurately setting the limiting bandwidth to ensure that the direct-axis current output based on voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is smoothly input, and can respond quickly when the input speed fluctuates violently, and a system is built to verify the feasibility of the strategy.

2. The voltage amplitude feedback system based on direct axis current fuzzy control output limiting according to claim 1, characterized in that: The fuzzy logic controller optimization design of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is achieved through the construction of a fuzzy rule system and the verification and iterative optimization of the controller performance; in the construction of the fuzzy rule system, it is firstly clarified that 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 precise system analysis, aiming to achieve dynamic matching between the input speed and the expected value of the direct-axis current; 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 the experimental data, a complete fuzzy rule system is constructed to achieve accurate mapping from input speed to expected value of direct-axis current; 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.

3. The voltage amplitude feedback system based on direct-axis current fuzzy control output limiting according to claim 1, characterized in that: The optimal selection of the weak-field control strategy of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is achieved through the control strategy optimization and control strategy implementation mechanism; the control strategy optimization achieves the priority of ensuring appropriate direct-axis current output when the current amplitude is too large by controlling the AC and DC axis currents respectively, thereby ensuring that the subsequent load will not be damaged by overvoltage; the control strategy implementation mechanism is based on the weak-field control strategy of 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 to be 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 achieving precise adjustment of the weak-field control of the generator.

4. The voltage amplitude feedback system based on direct axis current fuzzy control output limiting according to claim 1, characterized in that: The dynamic limiting strategy of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting is realized through limiting bandwidth setting, experimental verification and performance evaluation. The limiting bandwidth setting is based on the direct-axis current value output by the fuzzy controller, and the upper and lower boundaries of the limiting are scientifically set; through step-by-step experimental verification, the limiting bandwidth is selected to ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth when the input speed is slow, and the direct-axis current can be adjusted in time when the input speed fluctuates violently, so as to achieve a fast-response limiting bandwidth; The experimental verification and performance evaluation conducts simulation experiments under different working conditions, compares the performance of different control systems, and verifies the feasibility of the voltage amplitude dynamic feedback weak magnetic voltage stabilization strategy with direct-axis current fuzzy control limiting; the system has the stability of the voltage amplitude feedback weak magnetic strategy under stable working conditions, and at the same time, it shows the robustness of the fuzzy control weak magnetic strategy with speed as input under extreme working conditions, which provides solid technical support for the stable operation of permanent magnet synchronous generators in the field of renewable energy power generation.

5. The voltage amplitude feedback system based on direct axis current fuzzy control output limiting according to claim 2, characterized in that: The steps of optimizing the design of the fuzzy logic controller of the voltage amplitude feedback system based on the direct-axis current fuzzy control output limiting are as follows: Step 1: Design of fuzzy controller: Under various load conditions, input different direct-axis current values, and systematically record the corresponding maximum voltage-stabilizing speed. Based on the analysis results of the experimental data, design the membership function and fuzzy rules to ensure that the fuzzy controller can intelligently and accurately output reasonable direct-axis current values ​​based on the input speed information. Step 2: Optimize and select the weak magnetic control strategy; This is achieved through the control strategy optimization and control strategy implementation mechanism; The optimization strategy controls the AC and DC axis currents respectively to ensure that the appropriate DC axis current output is prioritized when the current amplitude is too large; The implementation mechanism is based on the weak magnetic field control strategy of voltage amplitude feedback. The direct axis current is directly obtained 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 to achieve precise adjustment of the generator weak magnetic field control. Step three, dynamic limiting strategy; achieved through limiting bandwidth setting and experimental verification and performance evaluation; set the upper and lower boundaries of the limit according to the direct-axis current value output by the fuzzy controller, and select a limiting bandwidth that can ensure that the direct-axis current output by the voltage amplitude feedback has sufficient fluctuation bandwidth and can adjust the direct-axis current in time to achieve rapid response; through simulation experiments under different working conditions, verify the feasibility of the voltage amplitude dynamic feedback weak magnetic stabilization strategy of the direct-axis current fuzzy control limiting, as well as the stability and robustness of the system under different working conditions.

6. The voltage amplitude feedback system based on direct axis current fuzzy control output limiting according to claim 4, characterized in that: A voltage amplitude dynamic feedback weak magnetic voltage stabilization system with fuzzy control limiting based on the dynamic limiting strategy of the voltage amplitude feedback system with direct axis current fuzzy control output limiting, with the limiting bandwidth set; Its bandwidth limitation can be expressed as: Where: i dup 、i dlow The upper and lower limits are: i d1 is the direct-axis current regulated by the input speed; Δi d1 To set the bandwidth.

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