An aircraft brushless direct current generator voltage regulation method, device and storage medium

Abstract

The application discloses an airplane brushless direct-current generator voltage regulation method, device and storage medium. ∞ The airplane brushless direct-current generator voltage regulation method regards current mutation caused by sudden loading and unloading of large power or nonlinear load as external disturbance, and introduces H ∞ Robust controller is introduced for parameter uncertainty of three-stage generator. Through simulation verification, the method can effectively inhibit voltage fluctuation caused by external disturbance, improve steady-state and dynamic performance of the system, and has strong robustness. The application solves the technical problem of poor robustness and anti-interference ability of the existing generator voltage regulation using PI control.

Description

Technical Field

[0001] This invention belongs to the field of aircraft generator voltage regulation technology, specifically relating to a method for regulating the voltage of a 270V brushless DC generator for aircraft based on robust control. Background Technology

[0002] With the rapid development of multi-electric / all-electric technology in aircraft, the number of airborne electronic equipment and electric drive devices is increasing, placing higher demands on the reliability, fault tolerance, and power requirements of aircraft power generation systems. 270V high-voltage direct current (HVDC) power generation systems, due to their large capacity, high power density, high energy conversion efficiency, ease of maintenance, and high reliability, have become the mainstream system in the aerospace field.

[0003] With the increase in airborne electrical power, high-voltage direct current (HVDC) power generation systems need to provide greater capacity to meet the growing load power demands. Statistics show that in the future, nonlinear loads such as secondary power supplies and power electronic equipment on aircraft will consume approximately 80% of the power output of the power generation system. The nonlinear characteristics of loads such as regenerative braking, radar loads, and instantaneous start-up impact loads have a significant impact on the power generation system. Furthermore, the aging of components, load switching, and external environmental influences during aircraft operation can all cause perturbations in motor parameters, leading to uncertainties in the model. The adaptability and robustness of traditional PI control used in generator voltage regulation have deteriorated, making it unable to meet the high-precision, fast-response dynamic performance requirements of voltage regulation systems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies mentioned in the background art by proposing a robust control-based voltage regulation method for a 270V brushless DC generator in aircraft, so as to improve the robustness and anti-interference capability of the system, while improving the dynamic regulation performance of the generator.

[0005] The technical solution of this invention is: This invention first provides a method for regulating the voltage of a 270V brushless DC generator for aircraft based on robust control, characterized by comprising: Step 1: Establish a mathematical model of the three-stage brushless DC generator for aircraft, which includes a main generator, a main exciter, and an auxiliary exciter; Step 2: Based on the generator's own performance requirements and robust stability, H ∞ The controller design incorporates a hybrid sensitivity framework and transforms the hybrid sensitivity problem into H ∞ Optimal control problem under norm; Step 3: Select appropriate weighting functions based on the various performance requirements of the system; Step 4: Design H ∞A robust controller enables robust control of an aircraft's three-stage brushless DC generator under external disturbances and internal parameter perturbations.

[0006] The present invention also provides an electronic device, characterized in that it includes a memory and a processor, wherein the memory stores a program that can run on the processor, and the program, when executed by the processor, implements the steps of the above-described robust control-based aircraft 270V brushless DC generator voltage regulation method.

[0007] The present invention also provides an electronic device, a memory, characterized in that the memory stores at least one program, the at least one program being executable by at least one processor, the at least one program implementing the steps of the above-described robust control-based aircraft 270V brushless DC generator voltage regulation method when executed by the at least one processor.

[0008] Compared with existing solutions, the robust control-based voltage regulation method for aircraft 270V brushless DC generators of this invention can significantly shorten the voltage build-up time of the generator during startup, thereby quickly and accurately tracking the command signal and achieving smooth voltage build-up without overshoot. When a large-power nonlinear load is suddenly applied or removed, it has a faster response speed and a smoother recovery process, improving the system's anti-interference capability. When generator parameters are perturbed, it can ensure that the system quickly reaches a steady state, with low dependence on the model of the controlled object and strong robustness. Attached Figure Description

[0009] Figure 1 This is a flowchart of the aircraft 270V brushless DC generator voltage regulation method based on robust control according to Embodiment 1 of the present invention. Figure 2 This is the structure of the aircraft three-stage brushless DC power generation system according to Embodiment 1 of the present invention; Figure 3 This is a structural block diagram of the aircraft three-stage generator voltage regulation system according to Embodiment 1 of the present invention; Figure 4 H is the embodiment of the present invention 1 ∞ Standard design problem framework; Figure 5 The amplitude-frequency curves of the weighting functions w1 and w3 in Embodiment 1 of the present invention are shown. Figure 6 For PI control and H in Embodiment 1 of the present invention ∞ Output voltage response curve during controlled voltage build-up process; Figure 7 For PI control and H in Embodiment 1 of the present invention ∞ Output voltage response curve during controlled loading and unloading; Figure 8 For PI control and H in Embodiment 1 of the present invention∞ Output voltage response curve of motor under control during load switching; Figure 9 For PI control and H in Embodiment 1 of the present invention ∞ Output voltage response curve of a constant power load under control during load switching; Figure 10 For PI control and H in Embodiment 1 of the present invention ∞ Output voltage response curve during load switching under controlled pulse load; Figure 11 The output voltage response curve of the generator under PI control when the generator parameters change; Figure 12 H is the embodiment of the present invention 1 ∞ Output voltage response curve when generator parameters change under control. Detailed Implementation

[0010] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings:

[0011] Example 1 This embodiment provides a robust control-based method for regulating the voltage of a 270V brushless DC generator in an aircraft. This method is applied to applications such as... Figure 2 The aircraft's three-stage brushless DC power generation system shown consists of components such as an auxiliary exciter, a main exciter, a main generator, a rotating rectifier, and a full-bridge rectifier circuit. The auxiliary exciter is a rotating pole permanent magnet synchronous generator, while the main exciter and main generator are a rotating armature-type electrically excited synchronous motor and a rotating pole-type electrically excited synchronous motor, respectively.

[0012] The armature winding of the permanent magnet synchronous motor outputs three-phase AC power, which, after rectification, provides excitation current to the main exciter's excitation winding. The main exciter's armature winding generates three-phase AC power, which, after rectification by a rotating rectifier, supplies power to the main generator's excitation winding. The stator armature winding of the main generator outputs three-phase AC power, which, after passing through a full-bridge rectifier circuit, outputs 270V high-voltage DC power. By controlling the excitation current of the main exciter, the excitation current of the main generator can be indirectly adjusted, thereby achieving a stable output voltage.

[0013] like Figure 1 As shown, the voltage regulation method for a 270V brushless DC generator in an aircraft based on robust control in this embodiment includes the following steps: Step S1: Establish a mathematical model of the aircraft's three-stage brushless DC generator; First, mathematical models of the main generator, main exciter, and auxiliary exciter are established respectively, as follows: The auxiliary exciter is a permanent magnet synchronous generator, and its output voltage U IThe current is constant and, after rectification, can provide excitation current to the main exciter. The rectification section is a proportional element K. P Then the transfer function of the auxiliary exciter is:

[0014] If we ignore the voltage saturation characteristics and the effects of the armature winding transformer potential and damping winding, then under normal operation, the voltage amplitudes at the terminals of the main generator and the main exciter are proportional to the excitation voltage. Therefore, the transfer functions of the main exciter and the main generator can each be expressed by the following formula:

[0015] Where: K G —The ratio of incremental voltage at the main generator and main exciter terminals to the incremental excitation voltage;

[0016] t——Time constant of the excitation circuit when the main generator and main exciter are working normally.

[0017]

[0018] Where x d x q These are the direct-axis and quadrature-axis synchronous reactances of the synchronous generator, respectively, x ad For direct-axis armature reactive reactance; r L x L For the load circuit resistance and reactance, r f L f r0 is the resistance and inductance of the excitation winding, and r0 is the zero-sequence resistance of the synchronous generator; u oH u dH u qH These are the values ​​of Δu and Δu, respectively, for the voltage increment at the load end of the generator under rated conditions at the rated point H. d , Δu q The coefficient.

[0019] Based on the transfer functions of each stage of the three-stage generator, and neglecting the dynamic coupling between stages, the overall transfer function of the three-stage brushless DC generator can be obtained by connecting the three stages in series.

[0020] Step S2: Based on the generator's own performance requirements and robust stability, H ∞ The controller design incorporates a hybrid sensitivity framework and transforms the hybrid sensitivity problem into H ∞ The optimal control problem under the norm is as follows: The structural block diagram of the three-stage brushless DC generator voltage regulation system is as follows: Figure 3As shown, K is the voltage regulator controller, G is the controlled object (a three-stage generator), and r, e, u, d, and y are the given input, system error, control input, external disturbance, and system output, respectively. The current surge caused by sudden addition or removal of high power or nonlinear load is considered as the output external disturbance d of the voltage regulator system. To address model uncertainties and external disturbances caused by inaccurate generator parameters or component aging, H... ∞ Voltage regulator design can be summarized as a mixed sensitivity problem.

[0021] definition:

[0022]

[0023]

[0024] S is the sensitivity function, characterizing the system's anti-interference capability, and T is the complementary sensitivity function, characterizing the system's robust stability. Since S + T = 1, it is impossible to simultaneously reduce S and T; the two characteristics are contradictory. Considering that system uncertainties usually occur in the high-frequency range, while external interference is mostly low-frequency signals, a suitable weighting function is selected for frequency band compromise. In practical applications, the controller typically has output limiting requirements, thus the selection of R is also appropriately restricted.

[0025] H of the three-stage generator voltage regulation system ∞ The model of the standard design problem is as follows Figure 4 As shown, the weighting function w1 represents the constraints on system performance, such as disturbance suppression; the weighting function w2 constrains the controller output amplitude, representing the limitation on the additive uncertainty of the controlled object; the weighting function w3 represents the limitation on the multiplicative uncertainty of the controlled object, which is determined by its own characteristics. z1, z2, and z3 are the evaluation signals of the system.

[0026] The transfer functions from the disturbance d to the desired output evaluation signals z1, z2, and z3 are w1S, w2R, and w3T, respectively. The objective function is selected as follows.

[0027] The hybrid sensitivity problem is transformed into solving for controller K to not only ensure the stability of the closed-loop system, but also to ensure that ||Φ|| ∞ Minimum. Based on the system's own performance requirements and robust stability, the problem is transformed into H by addressing the hybrid sensitivity issue. ∞ Optimal control problem under norm; Step S3: Select appropriate weighting functions based on the various performance requirements of the system; In H ∞In optimization design, the weighting function characterizes various performance indicators of the system, such as robust stability and anti-interference capability. Therefore, whether the controller design is reasonable and simple (low-order) and whether it can accurately reflect the various performance requirements of the designed system mainly depends on whether a suitable weighting function is selected, as follows: The selection of w1 is based on the system's performance requirements and serves as a weighting function for the sensitivity function S. Figure 4 It can be seen that S is both the transfer function from external interference d to system output y and the transfer function from given input r to system error e. External interference signals often appear in the low-frequency band. Therefore, in order to accurately track the given value and suppress interference, the gain value of w1 should be as large as possible in the low-frequency band and should attenuate rapidly after entering the high-frequency band.

[0028] The selection of w3 is based on the inherent characteristics of the controlled object. As a weighting function of the complementary sensitivity function T, it characterizes the norm bound of the multiplicative uncertainty of the controlled object, reflecting the robust stability, i.e., the high-frequency characteristic requirement. The nominal object model established in the low-frequency band can accurately describe the controlled object, but in the high-frequency band, various measurement noises and unmodeled dynamic characteristics will increase, inevitably leading to a decrease in accuracy. Therefore, the high-frequency gain of the uncertainty weighting function w3 should be as large as possible, and its amplitude-frequency characteristics should cover the unmodeled dynamics.

[0029] Figure 5 The figure shows the amplitude-frequency curves of the weighting functions w1 and w3. As can be seen from the figure, w1 meets the low-pass high-gain requirement, while w3 exhibits high-pass filtering characteristics.

[0030] The choice of w2 depends on the control input signal and is used as a weighting function of R. Figure 4 It can be seen that R is the transfer function from the given input r to the control input u. Introducing w2 can limit the size of the control input u. Considering the damage to the exciter caused by an excessively large u, its static gain should be taken as a large value. However, the system bandwidth is also affected by w2. In practical applications, in order to obtain a larger bandwidth, its static gain should be appropriately reduced. Therefore, the selection of w2 needs to comprehensively consider the system's saturation phenomenon and bandwidth requirements, and a compromise needs to be made. After w1 and w3 are selected, w2 can be adjusted as a constant, usually a small positive number is selected.

[0031] Step S4: Design H using the Robust Control Toolbox ∞ The controller is implemented in MATLAB as follows: The state-space equation matrix of a three-stage generator under control is converted into a transfer function form using the ss() function. The calling format is: Q=ss(A,B,C,D), where A,B,C,D are the state-space matrices and Q is the generated transfer function. Use the augtf() function to generate a generalized object with weighted functions for a three-stage generator voltage regulation system; the calling format is: P=augtf(Q,w1,w2,w3), where P is the state-space equation matrix of the generalized system; The optimal H is obtained using the hinfopt() function. ∞ The controller is called in the following format: [g,Gc,Gs]=hinfopt(P), where g is the minimum value of the optimal infinite norm, and Gc is the optimal H value expressed in state-space equations. ∞ Controller, Gs is the optimal H ∞ Tree variables of the state equations of the closed-loop system under the controller; The branch function is used to obtain the state space matrix of the controller; the calling format is: [A K B K C K D K =branch(Gc), where A K B K C K D K The state-space matrix equation of the voltage regulator K is in the form of the equation. The voltage regulator K is calculated using the zpk function; the calling format is: K=zpk(ss(A K B K C K D K Finally, the voltage regulator K obtained by solving is in the form of a transfer function with zero and pole distribution.

[0032] To verify the effectiveness of the method of the present invention, a complete three-stage brushless DC power generation system platform for aircraft was built in Matlab / Simulink, including generator, voltage regulator and various nonlinear loads. Multiple simulations were carried out under different conditions, and the results were compared and analyzed with traditional PI control.

[0033] Figure 6 The output voltage response curve during the voltage build-up process is shown. Compared to PI, H ∞ The control not only quickly and accurately follows the given voltage, achieving smooth voltage build-up without overshoot, but also significantly shortens the adjustment time, increases response speed, reduces the withstand voltage of components, and improves service life. To verify the dynamic performance of the voltage regulator, sudden application and removal of a 100kW resistive load were conducted at 0.6s and 1.0s after voltage build-up stabilization. The output voltage response curves are shown below. Figure 7 As shown. Under sudden load application, the overshoot under PI control is 24.2%, and the generator reaches a steady state after 0.24 seconds. Using H... ∞The overshoot was reduced by 31.2% compared to PI control, and the voltage recovered to a stable value after 0.06s. However, during sudden load unloading, the output voltage under PI control reached its peak value of 355V in 1.01s, with an overshoot of 31.5%, which no longer meets the requirements for high-voltage DC power supply characteristics in GJB181B. Therefore, the H-control method was adopted. ∞ During control, the system recovered to a stable state after 0.04s, with small overshoot and oscillation, and the process was smooth.

[0034] There are three main types of typical nonlinear loads on aircraft: motor loads, constant power loads, and pulse loads. To better test the anti-interference performance of the voltage regulator, after the generator voltage stabilized, three nonlinear load (10kW) sudden load applications were conducted. The pulse load had a pulsation period of 1ms. The output voltage response curves are shown below. Figures 8-10 As shown. Compared to PI, H ∞ The voltage regulator has smaller output voltage fluctuations and a significantly shorter recovery time, resulting in a faster response speed. This effectively improves the system's anti-interference performance and is more conducive to the stable flight of the aircraft under different operating conditions.

[0035] The aircraft's power generation system experiences temperature rise and changes in prime mover speed due to prolonged operation, causing variations in the generator's parameters. To verify H... ∞ The robustness of the voltage regulator was demonstrated through simulation under 10-fold perturbation of different generator parameters, and compared with that of PI control. The output voltage response curve is shown below. Figures 11-12 As shown in Table 1, the corresponding key performance parameters are as follows.

[0036] Table 1. Control performance of generator parameters under 10x perturbation

[0037] Depend on Figure 11 As shown in Table 1, when the generator parameters are perturbed, the output voltage of PI control oscillates violently, the response speed is slow, and under certain conditions, the output voltage even diverges, leading to system instability. Therefore, it has poor robustness. Meanwhile, H... ∞ A voltage regulator can quickly restore the system to a balanced state with minimal fluctuations, and the output voltage waveform remains essentially constant, i.e., H. ∞ The voltage regulator is insensitive to changes in the parameters of the controlled object, has low model dependence, and exhibits high robustness.

[0038] In summary, the robust control-based voltage regulation method for a 270V brushless DC generator for aircraft proposed in this invention can effectively suppress voltage fluctuations caused by external interference, improve the steady-state and dynamic performance of the system, and has strong robustness, considering the influence of system model uncertainties. It solves the technical problems of poor robustness and anti-interference ability of existing generator voltage regulation methods using PI control.

[0039] Example 2 This embodiment provides an electronic device, which includes a memory and a processor. The memory stores a program that can run on the processor. When the program is executed by the processor, it implements the steps of the robust control-based aircraft 270V brushless DC generator voltage regulation method in the above embodiment.

[0040] Example 3 This embodiment provides a memory that stores at least one program, which can be executed by at least one processor. When executed by the at least one processor, the at least one program implements the steps of the robust control-based aircraft 270V brushless DC generator voltage regulation method in the above embodiment.

[0041] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for regulating the voltage of a 270V brushless DC generator for aircraft based on robust control, characterized in that, include: Step 1: Establish a mathematical model of a three-stage brushless DC generator for aircraft. The three-stage brushless DC generator includes a main generator, a main exciter, and an auxiliary exciter. Ignoring dynamic coupling between stages, the overall transfer function of the three-stage brushless DC generator is: ， Where G1 is the transfer function of the auxiliary exciter, G G The transfer functions of the main exciter and main generator are given, and the Laplace operator s is a complex variable. ， ， Among them, U I U represents the output voltage of the auxiliary exciter. I K is a constant value. p K is the proportional adjustment coefficient of the rectifier stage. G It represents the ratio of the incremental voltage at the main generator and main exciter terminals to the incremental excitation voltage, and t represents the excitation circuit time constant when the main generator and main exciter are working normally; Step 2: Based on the generator's own performance requirements and robust stability, H ∞ The controller design incorporates a hybrid sensitivity framework and transforms the hybrid sensitivity problem into H ∞ Optimal control problem under norm; Step 2 includes the following specific steps: A three-stage brushless DC generator voltage regulation system structure is constructed, where K is the voltage regulator controller and G is the controlled object, a three-stage generator. definition: S is a sensitivity function that characterizes the system's anti-interference capability; definition: T is the complementary sensitivity function, which characterizes the robust stability of the system; definition: ; The current surge caused by sudden addition or removal of high power or nonlinear load is taken as the external output disturbance d of the voltage regulation system. The transfer functions from disturbance d to the three desired output evaluation signals z1, z2, and z3 are w1S, w2R, and w3T, respectively. The objective function is selected as follows: ； Among them, the weighting function w1 of the sensitivity function S represents the constraint on the system performance; the weighting function w2 of R represents the constraint on the controller output amplitude, representing the limitation on the additive uncertainty of the controlled object; the weighting function w3 of the complementary sensitivity function T represents the limitation on the multiplicative uncertainty of the controlled object, which is determined by its own characteristics. Transforming the mixed sensitivity problem into solving for controller K not only ensures the stability of the closed-loop system, but also makes ||Φ|| ∞ Minimum; Step 3: Select appropriate weighting functions based on the various performance requirements of the system; Step 4: Design H ∞ A robust controller enables robust control of an aircraft's three-stage brushless DC generator under external disturbances and internal parameter perturbations. Step 4 is implemented in MATLAB, including the following specific steps: The state-space equation matrix of a three-stage generator under control is converted into a transfer function form using the ss() function. The calling format is: Q=ss(A,B,C,D), where A,B,C,D are the state-space matrices and Q is the generated transfer function. Use the augtf() function to generate a generalized object with weighted functions for a three-stage generator voltage regulation system; the calling format is: P=augtf(Q,w1,w2,w3), where P is the state-space equation matrix of the generalized system; The optimal H is obtained using the hinfopt() function. ∞ The controller is called in the following format: [g,Gc,Gs]=hinfopt(P), where g is the minimum value of the optimal infinite norm, and Gc is the optimal H value expressed in state-space equations. ∞ Controller, Gs is the optimal H ∞ Tree variables of the state equations of the closed-loop system under the controller; The branch function is used to obtain the state space matrix of the controller; the calling format is: [A K B K C K ,D K =branch(Gc), where A K B K C K ,D K The state-space matrix equation of the voltage regulator K is in the form of the equation. The voltage regulator K is calculated using the zpk function; the calling format is: K=zpk(ss(A K B K C K ,D K Finally, the voltage regulator K obtained by solving is in the form of a transfer function with zero and pole distribution.

2. The method for regulating the voltage of a 270V brushless DC generator for aircraft based on robust control according to claim 1, characterized in that, The ratio of the incremental voltage at the main generator and main exciter terminals to the incremental excitation voltage: ； The excitation circuit time constant when the main generator and main exciter are operating normally: ； Where x d x q These are the direct-axis and quadrature-axis synchronous reactances of the synchronous generator, respectively, x ad For direct-axis armature reactive reactance; r L x L For the load circuit resistance and reactance, r f L f r0 is the resistance and inductance of the excitation winding, and r0 is the zero-sequence resistance of the synchronous generator; u oH u dH u qH These are the values ​​of Δu and Δu, respectively, for the voltage increment at the load end of the generator under rated conditions at the rated point H. d , Δu q The coefficient.

3. The method for regulating the voltage of a 270V brushless DC generator for aircraft based on robust control according to claim 1, characterized in that, Step 3 includes the following specific steps: Select an appropriate weighting function for frequency band trade-offs; among them, the gain value of w1 in the low frequency band should be as large as possible, and should attenuate rapidly after entering the high frequency band; the high frequency gain of w3 should be as large as possible, and should cover the unmodeled dynamics in terms of amplitude-frequency characteristics; after w1 and w3 are selected, a small positive number is selected as a constant for w2 adjustment.

4. An electronic device, characterized in that, It includes a memory and a processor, wherein the memory stores a program that can run on the processor, and the program, when executed by the processor, implements the steps of the robust control-based aircraft 270V brushless DC generator voltage regulation method according to any one of claims 1-3.

5. A memory, characterized in that, The memory stores at least one program, which can be executed by at least one processor. When executed by the at least one processor, the at least one program implements the steps of the robust control-based aircraft 270V brushless DC generator voltage regulation method according to any one of claims 1-3.

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