A control device for an aviation fuel pump control system

Abstract

The present invention provides an aviation fuel pump control system control device, and discloses a high-reliability estimation method for the fuel pump speed under a pump control architecture. Compared with the traditional method of directly equating the fuel pump speed with the motor speed, the method is more scientific and reasonable; with the estimated fuel pump speed as feedback, a fuel pump speed control loop is constructed, the closed-loop control of the fuel pump speed is realized, and the control stability domain of the fuel pump control system is expanded; through the closed-loop control of the fuel pump speed, the steady-state deviation between the actual fuel flow rate and the fuel pump speed when the fuel pump speed is unknown is effectively reduced, and the control accuracy of the fuel flow rate is improved, which is of great significance to the improvement of the working reliability of the aircraft engine; based on the estimated fuel pump speed, it has outstanding value for the fault prediction, diagnosis and isolation of the pump control system, as well as the health management of the aircraft engine.

Description

Technical Field

[0001] The invention belongs to a fuel control and regulation system, and in particular relates to a control device for an aviation fuel pump control system. Background Art

[0002] In recent years, there has been a surge of international research into more-electric and hybrid-electric aircraft engine technology, with varying degrees of research conducted on key components. The aircraft engine fuel pump control system, with its core architecture based on an electric fuel pump, is a key component in the development of more-electric and hybrid-electric engines and is considered by the industry to be a significant evolution in aircraft engine fuel control systems.

[0003] Compared to conventional valve-controlled systems based on proportional solenoid valves or electro-hydraulic servo valves, aircraft engine fuel pump control systems with electric fuel pumps offer a higher power-to-weight ratio, lower failure rates, and greater fuel efficiency. However, the elimination of the oil return mechanism presents a key challenge in controlling fuel flow within this architecture. To address this, researchers have divided the pump control system into an outer loop for fuel flow control and an inner loop for electric pump speed control. Research has focused on the fuel flow metering model and dual-loop control strategy, with preliminary validation of their performance.

[0004] It's worth noting that this dual-loop control structure treats the electric fuel pump as a whole, with the motor speed equivalent to the fuel pump speed. The rotating mechanism in the electric fuel pump consists of the motor, coupling, and fuel pump, which is directly driven by the motor through the coupling. The fuel pump and coupling present a certain degree of failure risk, leading to a mismatch between the fuel pump and motor speeds, and in severe cases, even stalling. Therefore, a dual-loop control approach that treats the electric fuel pump as a whole and equates the motor speed to the fuel pump speed presents certain safety risks and the risk of loss of control. Summary of the Invention

[0005] The present invention provides a control device for an aviation fuel pump control system, which realizes precise control of fuel flow by high-precision control of the fuel pump rotation speed, thereby reducing the risk of fuel flow loss of control.

[0006] A first aspect of the present invention provides a control device for an aviation fuel pump control system, wherein the pump control system includes: an electric fuel pump, a motor controller, and a flow controller; the control device includes: a post-pump pressure monitoring module, a fuel pump speed estimation module, and a fuel pump speed controller;

[0007] The pump pressure monitoring module is used to monitor the fuel pump's pump pressure in real time and send it to the fuel pump speed estimation module;

[0008] a fuel pump speed estimation module, configured to estimate the fuel pump speed based on the downstream pressure of the fuel pump and the motor speed obtained from the motor controller, and send the estimated fuel pump speed as the actual fuel pump speed to the fuel pump speed controller;

[0009] a fuel pump speed controller, configured to generate a motor command speed based on the actual fuel pump speed sent by the fuel pump speed estimation module and the fuel pump command speed sent by the flow controller, and send the generated motor command speed to the motor controller;

[0010] The motor controller is used to control the motor speed according to the motor speed command.

[0011] Optionally, the fuel pump speed estimation module is specifically used to estimate the fuel pump speed based on the post-pump pressure, the first weighting factor, the motor speed, and the second weighting factor.

[0012] Optionally, a fuel pump speed estimation module is specifically configured to obtain a preliminary estimated value of the fuel pump speed based on a preset mapping relationship between the fuel pump speed and the pump outlet pressure;

[0013] The fuel pump speed is obtained by multiplying the preliminary estimated value of the fuel pump speed and the motor speed by a first weighting factor and a second weighting factor, respectively.

[0014] Optionally, the post-pump pressure monitoring module includes: a high-speed A / D converter, a storage buffer, a direct memory access DMA controller, and a microprocessor; the storage buffer includes a front half area and a back half area;

[0015] The high-speed A / D converter is used to regularly sample the pressure monitoring signal of the fuel pump;

[0016] The DMA controller is used to determine whether the current interrupt is a half-full interrupt or a full interrupt, and if it is a half-full interrupt, the pressure monitoring signal is stored in the second half area, otherwise, it is stored in the first half area;

[0017] The DMA controller is further configured to generate a half-full interrupt when the first half area is fully stored, and generate a full interrupt when the second half area is fully stored.

[0018] The microprocessor is used to obtain the pressure monitoring signal from the front half zone when a half-full interrupt occurs, generate the pump back pressure according to the pressure monitoring signal, and clear the half-full interrupt flag; and is also used to obtain the pressure monitoring signal from the back half zone when a full interrupt occurs, generate the pump back pressure according to the pressure monitoring signal, and clear the full-full interrupt flag.

[0019] Optionally, the fuel pump speed controller includes: a deviation calculator, a PI controller, an output filter, an output limiter, and a feedforward controller; wherein,

[0020] The deviation calculator is used to calculate the fuel pump speed n r and the actual fuel pump speed n, calculate the deviation between the two e = n r -n, as the input of the PI controller;

[0021] A PI controller is used to obtain a command speed of the first motor according to the deviation e;

[0022] Feedforward controller, used to receive the fuel pump speed command n sent by the flow controller r , the fuel pump speed n r Performing differentiation and gain processing to obtain the command speed of the second motor;

[0023] The output of the PI controller is superimposed on the output of the feedforward controller and serves as the input of the output filter; the output filter is used to attenuate the high-frequency components in the first motor command speed and the second motor command speed, obtain the filtered motor command speed, and send it to the output limiter;

[0024] The output limiter is used to limit the filtered motor command speed and output it to the motor controller.

[0025] Optionally, the upper limit of the motor command speed output by the output limiter is 20000RPM, and the lower limit is 0RPM.

[0026] Optionally, the output filter is a first-order infinite impulse response low-pass filter, which has the form: y(k+1)=a*x(k+1)+(1-a)y(k);

[0027] Wherein, k is the sampling number, a is the coefficient, x(k+1) represents the output of the PI controller and the output of the feedforward controller superimposed at the k+1th sampling; y(k) represents the output of the output filter at the kth sampling; y(1)=x(1);

[0028] a is calculated using the formula Fc=a / ((1-a)*2π*Ts), where Fc is the cutoff frequency and Ts is the sampling period.

[0029] Optionally, the first weighting factor is 0.77 and the second weighting factor is 0.23.

[0030] The present invention provides an aviation fuel pump control system control device, and discloses a high-reliability estimation method for the fuel pump speed under a pump control architecture. Compared with the traditional method of directly equating the fuel pump speed with the motor speed, the method is more scientific and reasonable; with the estimated fuel pump speed as feedback, a fuel pump speed control loop is constructed, the closed-loop control of the fuel pump speed is realized, and the control stability domain of the fuel pump control system is expanded; through the closed-loop control of the fuel pump speed, the steady-state deviation between the actual fuel flow rate and the fuel pump speed when the fuel pump speed is unknown is effectively reduced, and the control accuracy of the fuel flow rate is improved, which is of great significance to the improvement of the working reliability of the aircraft engine; based on the estimated fuel pump speed, it has outstanding value for the fault prediction, diagnosis and isolation of the pump control system, as well as the health management of the aircraft engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the principle of the control device for the aviation fuel pump control system provided by the present invention;

[0032] Figure 2 The invention provides an aviation fuel pump control system control device. DETAILED DESCRIPTION

[0033] The aviation fuel pump control system control device provided by the present invention will be specifically explained below with reference to the accompanying drawings.

[0034] Figure 1 A schematic diagram of the principle of the control device for the aviation fuel pump control system provided by the present invention; Figure 2 The present invention provides an aviation fuel pump control system control device. Figure 1 and 2 As shown, the present invention provides an aviation fuel pump control system control device, comprising:

[0035] At least includes: a post-pump pressure monitoring module, a fuel pump speed estimation module, and a fuel pump speed controller;

[0036] ——The post-pump pressure monitoring module is used to monitor the post-pump pressure signal in real time and send it to the fuel pump speed estimation module.

[0037] The fuel pump speed estimation module is used to estimate the fuel pump speed based on the fuel pump outlet pressure and the motor speed obtained from the motor controller, and send the calculated fuel pump speed as the actual fuel pump speed to the fuel pump speed controller.

[0038] The fuel pump speed controller is used to perform real-time closed-loop control of the fuel pump speed based on the actual fuel pump speed sent by the fuel pump speed estimation module and the fuel pump command speed sent by the flow controller, and generate a motor speed command to send to the motor controller.

[0039] In the pump control system of the control device, the electric fuel pump consists of a motor and a fuel pump, which rotates under the control of the motor controller to provide the engine with fuel of a certain flow rate and pressure; the flow controller is the upper controller of the control device, which receives the flow command issued by the full authority digital electronic controller FADEC of the aircraft engine, realizes the closed-loop control of the flow, and generates the fuel pump speed command and sends it to the control device; the motor controller is the lower controller of the control device, which follows the motor speed command issued by the control device.

[0040] The post-pump pressure monitoring module includes a miniature piezoelectric pressure sensor, a pressure sensor mounting fixture, sensor lead wires, a charge amplifier, a voltage amplifier, a signal limiter, a high-speed A / D converter, high-speed real-time sampling, and a post-pump pressure signal processing algorithm. The miniature piezoelectric pressure sensor is installed at the fuel pump outlet of the electric fuel pump using the pressure sensor mounting fixture. The sensor lead wires connect to the charge amplifier. The charge amplifier converts the weak charge signal output by the pressure sensor into a weak voltage signal through an input capacitor, an operational amplifier, a T-type resistor network, and a feedback capacitor. The voltage amplifier then amplifies the weak voltage signal to a signal range suitable for microprocessor sampling. The signal limiter limits the voltage signal output by the voltage amplifier to prevent strong pulses superimposed on the signal from damaging subsequent circuits. The high-speed A / D converter samples the voltage signal input to its analog port in real time and quantizes it into a digital signal for use by the post-pump pressure signal processing algorithm. The post-pump pressure signal processing algorithm then performs a second-order infinite impulse response filter on the received digital signal to calculate the post-pump pressure.

[0041] The fuel pump speed estimation module includes a pressure-speed mapping table, a preliminary fuel pump speed estimate, and fuel pump speed fusion calculation. The pressure-speed mapping table represents the mapping relationship between pump pressure and fuel pump speed. The preliminary fuel pump speed estimate is based on the fuel pump pressure. A preliminary fuel pump speed estimate, n1, is obtained by looking up the pressure-speed mapping table.

[0042] The fuel pump speed fusion calculation takes the preliminary estimate n1 and the input motor speed n2 as input, combines the first weighting factor k1 and the second weighting factor k2, and estimates the fuel pump speed by n=n1*k1+n2*k2, where n is the fuel pump speed.

[0043] The fuel pump speed controller includes a deviation calculator, a PI controller, an output filter, an output limiter, and a feedforward controller. The deviation calculator is based on the fuel pump speed command n output by the flow controller. r and the fuel pump speed n estimated by the fuel pump speed estimation module, and calculate the deviation between the two e=n r -n, as the input of the PI controller, the PI controller adopts a parallel structure, and its frequency domain model is y1=e*(Kp+Ki / s), where Kp is the proportional factor, Ki is the integral factor, and 1 / s is the integral term of the PI controller.

[0044] The feedforward controller is used to accelerate the tracking of the fuel pump command speed; the output of the PI controller is superimposed on the output of the feedforward controller and serves as the input of the output filter; the output filter is used to attenuate the high-frequency components in the control, and the output limiter limits the output motor speed command to ensure it is within a reasonable range.

[0045] The implementation method of high-speed real-time sampling provided by the present invention is:

[0046] 1) Set the trigger mode of the high-speed A / D converter to timed sampling;

[0047] 2) Set the interrupt frequency of a 16-bit timer to 100 kHz and associate the timer interrupt with the A / D conversion start function;

[0048] 3) Set the A / D sampling result storage buffer;

[0049] 4) Set up the DMA controller so that it is associated with the A / D converter. The source address of the DMA is the A / D conversion result register, the destination address is the first address of the A / D sampling result storage buffer, and the buffer address automatic accumulation control mode is set;

[0050] 5) Configure DMA half-full and full interrupts. Read the first half of the A / D sampling result storage buffer in the half-full interrupt service routine and clear the half-full interrupt flag. Read the second half of the A / D sampling result storage buffer in the full-full interrupt service routine and clear the full-full interrupt flag.

[0051] The second-order infinite impulse response filter structure used in the post-pump pressure signal processing algorithm is:

[0052] Y(n+2)=X(n+2)*b0+X(n+1)*b1+X(n)*b2+Y(n+1)*a1+Y(n)*a2;

[0053] Among them, X(n+2) is the filter input of the n+2 cycle (also called the current cycle), X(n+1) is the filter input of the previous cycle, X(n) is the filter input of the previous two cycles, Y(n+2) is the filter output, Y(n+1) is the filter output of the previous cycle, Y(n) is the filter output of the previous two cycles, and a1, a2, b0, b1, and b2 are filter coefficients.

[0054] The filter cutoff frequency fc = 10KHz, the stopband attenuation is -40dB, the sampling rate is fs = 100KHz, and according to the filter calculation principle, the five filter coefficients a1, a2, b0, b1, and b2 can be determined.

[0055] The first weighting factor k1 is 0.77, and the second weighting factor k2 is 0.23.

[0056] The proportional factor Kp is 0.46, the integral factor Ki is 412, and the sampling period of the PI controller is 0.001s.

[0057] The feedforward controller is composed of the fuel pump command speed differential and the feedforward gain, and the feedforward gain is set to 0.24.

[0058] The output filter used is a first-order infinite impulse response low-pass filter of the form:

[0059] y(k+1)=a*x(k+1)+(1-a)y(k) where k is the sampling number, a is the coefficient, x(k+1) represents the output of the PI controller and the output of the feedforward controller superimposed at the k+1th sampling; y(k) represents the output of the output filter at the kth sampling; y(1)=x(1);

[0060] The coefficient a can be determined based on the filter sampling period and cutoff frequency, and the calculation method is:

[0061] Fc=(a) / ((1-a)*2π*Ts)

[0062] Set the cutoff frequency Fc = 100 Hz and the sampling period Ts = 0.001 s.

[0063] The upper limit of the output motor speed limit is 20000RPM and the lower limit is 0RPM.

[0064] The high-speed A / D converter is integrated into the microprocessor. The high-speed real-time sampling and post-pump pressure signal processing algorithms are all deployed inside the microprocessor and implemented by software.

[0065] The pressure-speed correspondence table is obtained from multiple test data, solidified during software development, and stored in the microprocessor's ROM. The initial estimation of the fuel pump speed is a binary table lookup operation. The first and second weighting factors are parameters stored in the microprocessor. The fuel pump speed fusion is implemented in software.

[0066] The time domain implementation of the PI controller is:

[0067] 1) Kpo = e*Kp;

[0068] 2) Kio = e*Ki / Ts;

[0069] 3) Sum+ = Kio;

[0070] 4)PIout=Kpo+Sum;

[0071] PIout is the output of the PI controller;

[0072] The output limit is set as follows: when the output motor speed is greater than 20000RPM, it is limited to 20000RPM; when the speed is less than 0RPM, the speed is limited to 0RPM.

[0073] Figure 2 The contents in the dotted box are all integrated into the microprocessor and implemented by software.

[0074] The above description is merely an embodiment of the present invention directed to the application of the present invention, which can enable those skilled in the art to more fully understand the present invention, but does not limit the present invention in any way. According to the technical solution of the present invention, many examples can be cited for the above embodiment. Any simple modification and change made to the above embodiment within the scope given by the technical solution of the present invention and all fall within the scope of protection of the technical solution of the present invention. A large number of experimental results show that the purpose of the present invention can be achieved within the scope proposed in the claims of the present invention.

Claims

1. A control device for an aviation fuel pump control system, characterized in that: The pump control system includes: an electric fuel pump, a motor controller, and a flow controller; the control device includes: a post-pump pressure monitoring module, a fuel pump speed estimation module, and a fuel pump speed controller; The pump pressure monitoring module is used to monitor the fuel pump's pump pressure in real time and send it to the fuel pump speed estimation module; a fuel pump speed estimation module, configured to estimate the fuel pump speed based on the downstream pressure of the fuel pump and the motor speed obtained from the motor controller, and send the estimated fuel pump speed as the actual fuel pump speed to the fuel pump speed controller; a fuel pump speed controller, configured to generate a motor command speed based on the actual fuel pump speed sent by the fuel pump speed estimation module and the fuel pump command speed sent by the flow controller, and send the generated motor command speed to the motor controller; A motor controller, used to control the motor speed according to a motor speed command; a fuel pump speed estimation module, specifically configured to obtain a preliminary estimated value of the fuel pump speed based on a preset mapping relationship between the fuel pump speed and the pump outlet pressure; Multiplying the preliminary estimated value of the fuel pump speed and the motor speed by a first weighting factor and a second weighting factor respectively to obtain the fuel pump speed; The fuel pump speed controller includes: a deviation calculator, a PI controller, an output filter, an output limiter, and a feedforward controller; wherein, The deviation calculator is used to calculate the fuel pump speed n r and the actual fuel pump speed n, calculate the deviation between the two e = n r -n, as the input of the PI controller; A PI controller is used to obtain a command speed of the first motor according to the deviation e; Feedforward controller, used to receive the fuel pump speed command n sent by the flow controller r , the fuel pump speed n r Performing differentiation and gain processing to obtain the command speed of the second motor; The output of the PI controller is superimposed on the output of the feedforward controller and serves as the input of the output filter; the output filter is used to attenuate the high-frequency components in the first motor command speed and the second motor command speed, obtain the filtered motor command speed, and send it to the output limiter; The output limiter is used to limit the filtered motor command speed and output it to the motor controller.

2. The control device according to claim 1, characterized in that The post-pump pressure monitoring module includes: a high-speed A / D converter, a storage buffer, a direct memory access DMA controller, and a microprocessor; the storage buffer includes a front half area and a back half area; The high-speed A / D converter is used to regularly sample the pressure monitoring signal of the fuel pump; The DMA controller is used to determine whether the current interrupt is a half-full interrupt or a full interrupt, and if it is a half-full interrupt, the pressure monitoring signal is stored in the second half area, otherwise, it is stored in the first half area; The DMA controller is further configured to generate a half-full interrupt when the first half area is fully stored, and generate a full interrupt when the second half area is fully stored. The microprocessor is used to obtain the pressure monitoring signal from the front half zone when a half-full interrupt occurs, generate the pump back pressure according to the pressure monitoring signal, and clear the half-full interrupt flag; and is also used to obtain the pressure monitoring signal from the back half zone when a full interrupt occurs, generate the pump back pressure according to the pressure monitoring signal, and clear the full-full interrupt flag.

3. The control device according to claim 1, characterized in that The upper limit of the motor command speed output by the output limiter is 20000RPM, and the lower limit is 0RPM.

4. The control device according to claim 1, characterized in that The output filter is a first-order infinite impulse response low-pass filter, which has the form: y(k+1)=a*x(k+1)+(1-a)y(k); Wherein, k is the sampling number, a is the coefficient, x(k+1) represents the output of the PI controller and the output of the feedforward controller superimposed at the k+1th sampling; y(k) represents the output of the output filter at the kth sampling; y(1)=x(1); a is calculated using the formula Fc=a / ((1-a)*2π*Ts), where Fc is the cutoff frequency and Ts is the sampling period.

5. The control device according to claim 1, characterized in that The first weighting factor is 0.77, and the second weighting factor is 0.23.

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