A redundant motor control system for manned electric helicopters

Abstract

This invention discloses a motor redundancy control system suitable for manned electric helicopters. The system includes: a current sensor, a three-phase voltage sensor, a motor position sensor, an inverse converter module, a motor control algorithm module, a current fault diagnosis and reconstruction module, a Clarke voltage inverter module, a speed and position monitoring module, and a position / speed signal fault diagnosis and reconstruction module. Applying this system ensures the flight safety of manned electric helicopters, preventing crashes due to power loss. This control system primarily addresses the current and position sensors, which are prone to failure during cruise in manned electric helicopters. Different redundancy control methods are proposed for each. When current and position sensors malfunction, the system can quickly diagnose the fault and reconstruct the position and current information using position and current reconstruction methods respectively. The fault information is then uploaded to the flight assistance display and control system to alert the pilot, allowing for an emergency landing at a suitable location, thus ensuring the stable operation of the manned electric helicopter's motor control system.

Description

Technical Field

[0001] This invention relates to the field of new energy aviation electric power system technology, and in particular to a motor redundancy control system suitable for manned electric helicopters. Background Technology

[0002] To ensure the safety and reliability of manned electric helicopters during cruise, a malfunction in the motor control system leading to a power system failure could directly result in a crash, endangering the pilot's life. Therefore, the reliability of the motor control system in manned electric helicopters faces stringent requirements. Due to current limitations in battery energy density, manned electric helicopters employ miniaturized and compact designs to increase flight time and reduce size and weight in their motor control systems. This miniaturization and compactness present challenges to the reliability and safety of the motor control system. Because of the unique nature of its application platform, the motor control system of manned electric helicopters, in addition to meeting specific functional, miniaturization, and lightweight requirements, must also possess high reliability to withstand complex weather conditions.

[0003] Manned electric helicopters widely use permanent magnet synchronous motors (PMSMs) which are small in size, have high power density, and low rotational inertia. Their motor control systems typically employ mature vector control systems. Because the PSM vector control system utilizes a current closed-loop technology to orient the stator and rotor flux linkages, current sensors and position sensors play a crucial role in acquiring current and rotor position information. When current sensors or position sensors fail, the control system cannot obtain current and rotor position information, which can cause catastrophic failures for traditional motor vector control systems. Furthermore, current sensors and position sensors are relatively weak links in the motor control system and are prone to failure.

[0004] To ensure the safe operation of the motor vector control system, it is necessary to identify the fault types, fault characteristics, and failure modes of current sensors and position sensors, and to formulate accurate fault diagnosis methods to quickly locate the fault location and cause, complete the fault handling, and ensure the reliable and stable operation of the motor vector control system. Therefore, a motor redundancy control system suitable for manned electric helicopters is proposed, which is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the present invention discloses a motor redundancy control system suitable for manned electric helicopters. When current and position sensors fail, the system can quickly diagnose the fault and reconstruct the position and current information by means of position and current reconstruction, so as to ensure the stable operation of the motor control system of manned electric helicopters.

[0006] The technical solution provided by this invention is specifically a motor redundancy control system suitable for manned electric helicopters. The motor redundancy control system includes: a current sensor, a three-phase voltage sensor, a motor position sensor, an inverse converter module, a motor control algorithm module, a current fault diagnosis and reconstruction module, a Clarke voltage inverter module, a speed and position monitoring module, and a position and speed signal fault diagnosis and reconstruction module.

[0007] The motor position sensor is mounted on the motor shaft and is used to collect motor position signals;

[0008] The speed and position monitoring module is connected to the motor position sensor signal and is used to convert the acquired motor position signal and speed into rotor angle θ and motor speed ω. e ;

[0009] The position and speed signal fault diagnosis and reconstruction module is connected to the speed and position monitoring module to monitor and determine whether the motor position sensor has failed. When the motor position sensor fails, it is used to reconstruct the motor position signal. The position and speed signal fault diagnosis and reconstruction module is connected to the motor control algorithm module to output the motor rotor angle and speed signals required by the motor control algorithm.

[0010] The current fault diagnosis and reconstruction module is connected to the current sensor and is used to determine whether the current sensor has failed. When a failure occurs, it is used to reconstruct the two-phase current signal output by the motor.

[0011] The current fault diagnosis and reconstruction module is connected to the position and speed signal fault diagnosis and reconstruction module, and is used to output the two-phase current signal of the motor required for position and speed signal reconstruction.

[0012] The current fault diagnosis and reconstruction module is connected to the motor control algorithm module and is used to output the two-phase current signal i required by the motor control algorithm. a_out and i b_out ;

[0013] The position and speed signal fault diagnosis and reconstruction module is connected to the motor control algorithm module and is used to output the motor speed signal ω. e_out and rotor angle θ out ;

[0014] The three-phase voltage sensor is installed on the three-phase power lines of the motor to collect the three-phase voltage u of the motor. a u b and u c ;

[0015] The Clarke voltage inverter module is connected to a three-phase voltage sensor and is used to convert the three-phase AC voltage u a ub and u c Transformed into a two-phase AC voltage u α and u β ;

[0016] The current fault diagnosis and reconstruction module is signal-connected to the Clarke voltage inverter module and is used to reconstruct the current signal and output the reconstructed two-phase motor current to the motor control algorithm module.

[0017] The motor control algorithm module uses the feedback motor speed signal ω e_out Rotor angle θ out The two-phase output current i of the motor a_out , and i b_out Simultaneously, based on the given motor speed ω, six SVPWM signals are output to drive the inverse converter module, which converts DC power into three-phase AC power to provide power to the motor.

[0018] Preferably, the Clarke voltage inverter module converts three-phase AC voltage into two-phase AC voltage according to the following formula:

[0019]

[0020] Among them, u α and u β These are the two-phase AC voltages of the motor in the α and β coordinate systems, u. a u b and u c This is the three-phase input voltage for the motor.

[0021] Further optimization involves the current fault diagnosis and reconfiguration module performing current reconfiguration based on the current sensor failure control strategy, outputting the reconfigured two-phase currents as follows: and

[0022] The failure control strategy for the current sensor is as follows:

[0023] The voltage loop equation of the stator of the permanent magnet synchronous motor in the α and β two-phase coordinate systems can be expressed as:

[0024]

[0025] Among them, u α and u β These are the voltages of the stator of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively; i α and i β These are the stator currents of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively; R s For stator resistance; L s For stator impedance; e α and eβ These are the back electromotive forces of the stator of the permanent magnet synchronous motor in the α and β two-phase coordinate systems, respectively;

[0026] The back electromotive force of the stator of a permanent magnet synchronous motor in the α and β two-phase coordinate systems can be expressed as:

[0027]

[0028] Among them, Ψ f For permanent magnet flux linkage; p n ω is the number of magnetic pole pairs; e θ is the motor speed; θ is the motor rotor angle;

[0029] Based on equations (2) and (3), an observer of the following form is designed:

[0030]

[0031] Where G is the observer gain matrix, which can be determined based on the operating load characteristics of the manned electric helicopter; ω e～ The motor speed signal from the previous sampling period; θ ～ The rotor angle of the motor in the previous sampling period is denoted by J; J is the moment of inertia of the motor, which can be approximated as a constant; T is the rotor angle of the motor in the previous sampling period. l For the motor load torque, the load torque of a manned electric helicopter at a given rotor speed can be approximated as a constant; F v i is the coefficient of viscous friction of the motor, which can be approximated as a constant; α and i β These are the observed values ​​of the motor stator current;

[0032] Based on the observation device, the stator current i of the motor is observed. α and i β The estimated values ​​of the three-phase stator currents of the motor can be obtained by performing an inverse Clarke transform. and Complete the reconfiguration of the stator current;

[0033]

[0034] Further optimization involves the current fault diagnosis and reconstruction module determining whether a current sensor failure has occurred using a current sensor fault diagnosis method. If no current sensor failure has occurred, but a motor position sensor failure has occurred, the motor position and speed signal fault diagnosis and reconstruction module reconstructs the motor position and speed signal according to a position and speed signal reconstruction method, and outputs the reconstructed motor speed. and rotor angle

[0035] The current sensor fault diagnosis method is as follows: Since the instantaneous sum of the three-phase stator currents of the motor is zero, dual current sensors are used, respectively arranged on phases a and b. To detect current sensor faults, the current values ​​collected by the current sensors are compared with the current information collected in the previous sampling cycle, and the difference is calculated.

[0036]

[0037] Where, Δi a The current difference between phase a and phase i; a～ and i b～ The value is the sampled value from the previous sampling period of the current sensor; Δi b This represents the current difference between phase b.

[0038] During cruise, the motor operating phase current of the manned electric helicopter will not change abruptly. Given a maximum permissible error current threshold Δi0 for the manned electric helicopter motor, when the current difference between phase a and phase b exceeds the threshold Δi0, it can be determined that the current sensor is faulty, and the motor stator current needs to be reconfigured. The output current of the current fault diagnosis and reconfiguration module must meet the following requirements:

[0039]

[0040] Among them, i a_out and i b_out These are the phase a and phase b currents of the permanent magnet synchronous motor output by the current fault diagnosis and reconfiguration module, respectively.

[0041] Further optimization involves the motor position and speed signal reconstruction module reconstructing the motor position and speed signal according to the position and speed signal reconstruction method, and outputting the reconstructed motor speed. and rotor angle

[0042] Given the two-phase current i of the permanent magnet synchronous motor a_out and i b_out The stator current of a permanent magnet synchronous motor in the α and β phase coordinate systems can be expressed as:

[0043]

[0044] Among them, i α and i β These are the stator currents of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively.

[0045] According to sliding mode theory, the back electromotive force of the stator of a permanent magnet synchronous motor in the α and β two-phase coordinate systems can be expressed as a switching function of the independent variable:

[0046]

[0047] Where k is the modulation coefficient, which can be obtained from the load characteristics of the manned electric helicopter motor; i α～ and i β～ These are the sampled values ​​of the motor stator current obtained in the previous sampling period; and This represents the difference between the measured and estimated current values ​​in the α and β two-phase coordinate systems.

[0048] The back EMF in equation (9) is filtered using a low-pass filter to remove high-frequency observation noise from the back EMF.

[0049]

[0050] Where, ω c e is the cutoff frequency of the low-pass filter. α and e β These are the back electromotive forces of the permanent magnet synchronous motor stator after filtering in the α and β two-phase coordinate systems, respectively.

[0051] From equations (3) and (10), we can obtain

[0052]

[0053] in, and These are the estimated values ​​for motor speed and rotor angle, respectively.

[0054] Further preferably, the position and speed signal fault diagnosis and reconstruction module determines whether a motor position sensor failure has occurred based on the motor position sensor fault diagnosis method; if no motor position sensor failure has occurred, it outputs the motor rotor angle θ. out =θ and rotational speed ω e_out =ω r This is given to the motor control algorithm module;

[0055] If the motor position sensor fails, the current sensor will collect the input current i of the two phases of the motor respectively. a_out and i b_ou ;

[0056] The fault diagnosis method for the motor position sensor is as follows: The maximum permissible error threshold for the motor rotor angle is set to Δθ0. When the maximum permissible error value of the motor rotor angle exceeds the threshold Δθ0, it can be determined that the position sensor is faulty, and the motor rotor angle needs to be reconstructed. The position and speed signal fault diagnosis and reconstruction module outputs the motor rotor angle and speed that meet the following requirements:

[0057]

[0058] Where, θ ～ θ is the sampled value of the motor rotor angle in the previous sampling period;out and ω e_out These are the reconstructed output values ​​of the motor rotor angle and speed, respectively.

[0059] Further preferably, when both the current sensor and the motor position sensor are diagnosed as faulty, the position and speed signal fault diagnosis and reconstruction module uses the current signal i output by the motor fault diagnosis and reconstruction module in the previous sampling cycle. a～ and i b～ Perform motor position signal reconstruction and output motor rotor angle θ out and rotational speed ω e_out The motor control algorithm module outputs the rotor angle and motor speed signals required by the motor control algorithm; the motor fault diagnosis and reconstruction module outputs the motor rotor angle θ from the previous sampling period based on the position and speed signals. ～ Perform motor current signal reconstruction and output the two-phase motor current i. a_out and i b_out This is provided to the motor control algorithm module to output the two-phase current signals of the motor required by the motor control algorithm.

[0060] This invention provides a redundant motor control system for manned electric helicopters. Its application ensures flight safety and prevents power loss leading to crashes. The system primarily addresses the current and position sensors, which are prone to failure during flight. Different redundant control methods are proposed for each sensor. When these sensors malfunction, the system can quickly diagnose the fault and reconstruct the position and current information using position and current reconstruction methods, ensuring the stable operation of the manned electric helicopter's motor control system.

[0061] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the disclosure of the present invention. Attached Figure Description

[0062] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 This is a redundant control block diagram of a manned electric helicopter motor provided in an embodiment of the present invention;

[0065] Figure 2 This is a flowchart illustrating the redundant control of the motor of a manned electric helicopter, as provided in an embodiment of the present invention. Detailed Implementation

[0066] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of systems consistent with some aspects of the invention as detailed in the appended claims.

[0067] During the flight of a manned electric helicopter, a specific fault diagnosis method for the current sensor should be selected to monitor the operating status of the motor control system in real time. Common fault diagnosis methods include hardware redundancy and algorithm diagnosis. Hardware diagnosis requires redundant sensors to be placed in the same location within the motor controller to ensure the safe and reliable operation of the motor vector control system. However, manned electric helicopters have stringent requirements regarding the weight and size of their motor control systems, making hardware redundancy unsuitable. Algorithm diagnosis mainly includes three types: model-based, signal-based, and knowledge-based. Signal-based and knowledge-based fault diagnosis methods require separate observer design for fault-tolerant control, and cannot provide the necessary estimates for fault-tolerant control of the motor control system, increasing its complexity. Therefore, they cannot be applied to the motor control system of manned electric helicopters.

[0068] The model-based method utilizes a mathematical model of the motor for fault diagnosis. A corresponding intelligent observer is established based on the motor's mathematical model to estimate the state, and this estimate is then compared with the sensor's measurement signal. The magnitude of the residual signal is used to evaluate the sensor's operating state. By rationally designing residual thresholds to set two operating states for the sensor—fault and normal—and conducting extensive training on the residual values, accurate online fault monitoring of the current sensor's operating conditions can be achieved, meeting the online monitoring and fault diagnosis requirements of current sensors in the motor control system of manned electric helicopters.

[0069] When a failure of a motor current sensor is determined, the number, type, characteristics, and mode of failure should first be identified based on the current sensor's topology and operating principle. A suitable current sensor failure control strategy should then be selected. When only one motor phase current sensor fails, a zero-sequence model current reconstruction method can be used to avoid sudden changes in torque or flux linkage, reconstructing the motor phase current and achieving a natural transition between normal and fault operation, ensuring the flight safety of the manned electric helicopter. When more than one current sensor fails, a mathematical model of the motor control system after the fault can be established based on the characteristics of the system topology and the relationship between the motor phase current and the bus current. This allows for a smooth switch to a single-current control mode, ensuring the operation of the motor control system. Cases where more than one current sensor fails are relatively rare.

[0070] To address the potential failure of the motor position sensor in a manned electric helicopter, a fault database for the motor position sensor needs to be established during flight. A fault diagnosis method for the motor position sensor should be proposed to monitor its operation and diagnose faults promptly. A model-based fault diagnosis method is employed, designing a motor rotor position observer. Based on advanced artificial intelligence theories such as sliding mode control, the observer obtains observed values ​​of rotor position and speed, determining whether the motor position sensor has failed. If a motor position sensor failure is confirmed, a smooth switch to sensorless motor control should be implemented. However, the load torque of the manned electric helicopter motor increases quadratically with speed. During flight, the motor operates at high speeds and with high torque. Therefore, a nonlinear, precise control model without a position sensor is required. A full-order state observer is used to estimate the motor rotor angle, meeting the requirements of the motor control system and ensuring stable operation of the motor control system, thus guaranteeing the flight safety of the manned electric helicopter.

[0071] Therefore, considering the susceptibility of current and position sensors to failure in the motor control systems of existing manned electric helicopters, and to ensure the safe operation of the motor vector control system, this implementation plan provides a redundant motor control system suitable for manned electric helicopters. This system identifies the fault types, characteristics, and failure modes of current and position sensors, develops accurate fault diagnosis methods, and quickly locates and resolves faults to ensure reliable and stable operation of the motor vector control system. Figure 1 As shown, the redundant control system for the motor includes: current sensor 1, three-phase voltage sensor 2, motor position sensor 3, inverter module 4, motor control algorithm module 5, Clarke voltage inverter module 6, speed and position monitoring module 7, current fault diagnosis and reconstruction module 8, and position and speed signal fault diagnosis and reconstruction module 9.

[0072] The motor position sensor 3 is mounted on the motor shaft and is used to collect motor position signals and speed.

[0073] Speed ​​and position monitoring module 7 is connected to motor position sensor 3 and is used to convert the motor position signal into rotor angle θ and motor speed ω. e ;

[0074] The position and speed signal fault diagnosis and reconstruction module 9 is connected to the speed and position monitoring module 7 and is used to monitor and determine whether the motor position sensor 3 has failed. When the motor position sensor fails, it is used to reconstruct the motor position signal. The position and speed signal fault diagnosis and reconstruction module 9 is connected to the motor control algorithm module 5 and is used to output the rotor angle and motor speed signals required by the motor control algorithm.

[0075] Current sensor 1 is installed on the three-phase power lines of the motor to collect the two-phase input current i of the motor. a and i b ;

[0076] The current fault diagnosis and reconstruction module 8 is connected to the current sensor 1 and is used to determine whether the current sensor has failed.

[0077] The current fault diagnosis and reconstruction module 8 is connected to the position and speed signal fault diagnosis and reconstruction module 9, which is used to reconstruct the motor position and speed signal.

[0078] The current fault diagnosis and reconstruction module 8 is connected to the motor control algorithm module 5 and is used to output the two-phase current signal of the motor required by the motor control algorithm.

[0079] The position and speed signal fault diagnosis and reconstruction module 9 is connected to the motor control algorithm module 5 and is used to output the motor speed signal ω. e_out and rotor angle θ out ;

[0080] The three-phase voltage sensor 2 is installed on the three-phase power lines of the motor to collect the three-phase voltage u of the motor. a u b and u c ;

[0081] Clarke voltage inverter module 6 is connected to three-phase voltage sensor 2 to convert the three-phase voltage u a u b and u c Transformed into a two-phase AC voltage u α and u β ;

[0082] The current fault diagnosis and reconfiguration module 8 is connected to the Clarke voltage inverter module 6 by signal, and is used to reconfigure the current and output the reconfigured two-phase motor current to the motor control algorithm module 5.

[0083] Motor control algorithm module 5 uses the feedback motor speed signal ω e_out Rotor angle θ out The two-phase output current i of the motor a_out , and i b_out Simultaneously, based on the given motor speed ω, six SVPWM signals are output to drive the inverse converter module 4, which converts DC power into three-phase AC power to provide power to the motor.

[0084] The Clarke voltage inverter module described above converts three-phase AC voltage into two-phase AC voltage according to the following formula:

[0085]

[0086] Among them, u α and u β These are the two-phase AC voltages of the motor in the α and β coordinate systems, u. a u b and u c This is the three-phase input voltage for the motor.

[0087] The aforementioned current fault diagnosis and reconfiguration module 8 performs current reconfiguration based on the current sensor failure control strategy, and outputs the reconfigured two-phase currents as follows: and

[0088] The failure control strategy for the current sensor is as follows:

[0089] The voltage loop equation of the stator of a permanent magnet synchronous motor in the α and β phase coordinate systems can be expressed as follows:

[0090]

[0091] Among them, u α and u β These are the voltages of the stator of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively; i α and i β These are the stator currents of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively; R s For stator resistance; L s For stator impedance; e α and e β These are the back electromotive forces of the stator of the permanent magnet synchronous motor in the α and β two-phase coordinate systems, respectively;

[0092] The back electromotive force of the stator of a permanent magnet synchronous motor in the α and β two-phase coordinate systems can be expressed as:

[0093]

[0094] Among them, Ψ f For permanent magnet flux linkage; p n ω is the number of magnetic pole pairs; e θ is the motor speed; θ is the motor rotor angle;

[0095] Based on equations (2) and (3), an observer of the following form is designed:

[0096]

[0097] Where G is the observer gain matrix, which can be determined based on the operating load characteristics of the manned electric helicopter; ω e～ The motor speed signal from the previous sampling period; θ ～ The rotor angle of the motor in the previous sampling period is denoted by J; J is the moment of inertia of the motor, which can be approximated as a constant; T is the rotor angle of the motor in the previous sampling period. l For the motor load torque, the load torque of a manned electric helicopter at a given rotor speed can be approximated as a constant; F v i is the coefficient of viscous friction of the motor, which can be approximated as a constant; α and i β These are the observed values ​​of the motor stator current;

[0098] According to the observer in equation (4), the stator current i of the motor is observed. α and i β The estimated values ​​of the three-phase stator currents of the motor can be obtained by performing an inverse Clarke transform. and Complete the reconfiguration of the stator current;

[0099]

[0100] The aforementioned current fault diagnosis and reconstruction module 8 determines whether a current sensor failure has occurred using a current sensor fault diagnosis method. If no current sensor failure has occurred, but a motor position sensor failure has occurred, the motor position and speed signal fault diagnosis and reconstruction module 9 reconstructs the motor position and speed signal according to a position and speed signal reconstruction method, and outputs the reconstructed motor speed. and rotor angle

[0101] The fault diagnosis method for the current sensor is as follows: Since the instantaneous sum of the three-phase stator currents of the motor is zero, dual current sensors are used, respectively arranged on phases a and b. To detect current sensor faults, the current values ​​collected by the current sensors are compared with the current information collected in the previous sampling cycle, and the difference is calculated.

[0102]

[0103] Where, Δi a The current difference between phase a and phase i; a～ and i b～ The value is the sampled value from the previous sampling period of the current sensor; Δi b This represents the current difference between phase b.

[0104] During the cruise of a manned electric helicopter, the operating phase current of the motor will not change abruptly. Given a maximum permissible error current threshold Δi0 for the manned electric helicopter motor, when the current difference between phase a and phase b exceeds the threshold Δi0, it can be determined that the current sensor is faulty, and the stator current of the motor needs to be reconfigured. The output current of the current fault diagnosis and reconfiguration module 8 satisfies the following:

[0105]

[0106] Among them, i a_out and i b_out These are the phase a and phase b currents of the permanent magnet synchronous motor output by the current fault diagnosis and reconfiguration module 8, respectively.

[0107] The aforementioned motor position and speed signal fault diagnosis and reconstruction module 9 reconstructs the motor position and speed signal according to the position and speed signal reconstruction method, and outputs the reconstructed motor speed. and rotor angle

[0108] Given the two-phase current i of the permanent magnet synchronous motor a_out and i b_out The stator current of a permanent magnet synchronous motor in the α and β phase coordinate systems can be expressed as:

[0109]

[0110] Among them, i α and i β These are the stator currents of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively.

[0111] According to sliding mode theory, the back electromotive force of the stator of a permanent magnet synchronous motor in the α and β two-phase coordinate systems can be expressed as a switching function of the independent variable:

[0112]

[0113] Where k is the modulation coefficient, which can be obtained from the load characteristics of the manned electric helicopter motor; i α～ and i β～ These are the sampled values ​​of the motor stator current obtained in the previous sampling period; and The difference between the measured and estimated current values ​​in the α and β two-phase coordinate systems;

[0114] The back electromotive force in equation (9) is filtered using a low-pass filter to remove high-frequency observation noise from the back electromotive force.

[0115]

[0116] Where, ω c e is the cutoff frequency of the low-pass filter. α and e β These are the back electromotive forces of the permanent magnet synchronous motor stator after filtering in the α and β two-phase coordinate systems, respectively.

[0117] From equations (3) and (10), we can obtain

[0118]

[0119] in, and These are the estimated values ​​for motor speed and rotor angle, respectively.

[0120] The aforementioned position sensor fault diagnosis module 6 determines whether a motor position sensor failure has occurred based on the motor position sensor fault diagnosis method; if no motor position sensor failure has occurred, it outputs the motor rotor angle θ. out =θ and rotational speed ω e_out =ω e , to motor control algorithm module 2;

[0121] If the motor position sensor fails, the current sensor will collect the input current i of the two phases of the motor respectively. a_out and i b_out Reconstruct the motor position and speed signals;

[0122] The above-mentioned fault diagnosis method for motor position sensors is as follows: The maximum permissible error threshold for the motor rotor angle is set to Δθ0. When the maximum permissible error value of the motor rotor angle exceeds the threshold Δθ0, it can be determined that the position sensor is faulty, and the motor rotor angle needs to be reconstructed. After reconstruction, the output motor rotor angle and speed satisfy the following:

[0123]

[0124] Where, θ ～ θ is the sampled value of the motor rotor angle in the previous sampling period; out and ω e_out These are the reconstructed output values ​​of the motor rotor angle and speed, respectively.

[0125] When both current sensor 1 and motor position sensor 3 are diagnosed as faulty, the position and speed signal fault diagnosis and reconstruction module 9 uses the current signal i output by the motor fault diagnosis and reconstruction module 8 in the previous sampling cycle. a～ and i b～ Perform motor position signal reconstruction and output motor rotor angle θ out and rotational speed ω e_out The motor control algorithm module 5 outputs the rotor angle and motor speed signals required by the motor control algorithm; the motor fault diagnosis and reconstruction module 8 outputs the motor rotor angle θ from the previous sampling period based on the position and speed signals from the fault diagnosis and reconstruction module 9. ～ Perform motor current signal reconstruction and output the two-phase motor current i. a_out and i b_out The motor control algorithm module 5 is used to output the two-phase current signals of the motor required by the motor control algorithm.

[0126] The working principle of the motor redundancy control system for manned electric helicopters provided in this implementation plan is as follows:

[0127] (1) The motor position sensor 3, installed on the motor shaft, collects the motor position signal, and the speed and position monitoring module 7 converts the motor position signal into the motor speed ω. e and rotor angle θ;

[0128] (2) Position and speed signal fault diagnosis and reconstruction module 9 determines whether a motor position sensor failure has occurred based on the motor position sensor fault diagnosis method. If no motor position sensor failure has occurred, it outputs the motor rotor angle θ. out =θ and rotational speed ω e_out =ω e , to motor control algorithm module 5;

[0129] (3) If the motor position sensor fails, the two-phase motor current i output from the current fault diagnosis and reconstruction module 8 will be collected respectively. a_out and i b_out The motor position and speed signals are reconstructed using the position and speed signal reconstruction method, and the reconstructed motor speed is output. and rotor angle

[0130] Compared with the traditional vector control of existing motors, it can reconstruct the position information required by the motor control system by reconstructing the position signal when the position sensor on the motor shaft of the manned electric helicopter fails, ensuring that the aircraft motor control system will not stop due to the loss of position signal and ensuring the flight safety of the manned electric helicopter.

[0131] (4) If both current sensor 1 and motor position sensor 3 are diagnosed as faulty, the position and speed signal fault diagnosis and reconstruction module 9 will use the current signal i output by the motor fault diagnosis and reconstruction module 8 in the previous sampling cycle. a～ and i b～ Perform motor position signal reconstruction and output motor rotor angle θ out and rotational speed ω e_out ;

[0132] (5) Current fault diagnosis and reconfiguration module 8 determines whether a current sensor failure has occurred using the current sensor fault diagnosis method. If a current sensor failure occurs, the three-phase voltage sensors installed on the three-phase power lines of the motor collect the three-phase voltage u of the motor respectively. a u b and u c Three-phase voltage u a u b and u c Converted into two-phase AC voltage u via Clarke voltage inverter module α and u β The current fault diagnosis and reconfiguration module 8 performs current reconfiguration based on the current sensor failure control strategy, and outputs the reconfigured two-phase currents as follows: and Provided to the motor control algorithm module. Compared with the existing traditional vector control of motors, it can reconstruct the three-phase current through current reconstruction when the current sensor in the motor control system of the manned electric helicopter fails, ensuring that the motor control system will not stop due to the loss of three-phase current signals, and ensuring that the manned electric helicopter will not crash due to loss of power;

[0133] (6) If both current sensor 1 and motor position sensor 3 are diagnosed as faulty, the motor fault diagnosis and reconstruction module 8 will output the motor rotor angle θ from the previous sampling cycle of the position and speed signal fault diagnosis and reconstruction module 9. ～ Perform motor current signal reconstruction and output the two-phase motor current i. a_out and i b_out ;

[0134] (7) The motor control algorithm module calculates the motor speed information ω based on the feedback motor speed signal. e_out Rotor angle θ out Motor current i a_out and i b_out Simultaneously, based on the given motor speed ω, six SVPWM signals are output to drive the inverter module. The inverter module converts DC power into three-phase AC power to provide energy to the motor. Its control flowchart is as follows: Figure 2 As shown

[0135] This invention obtains a redundant control system for the motor of a manned electric helicopter by reconstructing current and position signals, thereby improving the reliability of the motor control system of the manned electric helicopter without increasing hardware costs or weight.

[0136] On July 11, 2020, a single-rotor electric helicopter with a tail rotor layout was successfully developed and made its maiden flight using the above-mentioned system. By applying the present invention to the motor control of the aircraft and replacing the traditional motor controller, the results of the comparison with the traditional motor control showed that the control method of the present invention effectively improved the reliability of the aircraft motor control. In the event of current and motor position sensor failures, the stable operation of the aircraft motor controller can be guaranteed, thereby improving the safety of the aircraft flight.

[0137] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

Claims

1. A redundant motor control system suitable for manned electric helicopters, characterized in that, The redundant control system for the motor includes: a current sensor (1), a three-phase voltage sensor (2), a motor position sensor (3), an inverter module (4), a motor control algorithm module (5), a Clarke voltage inverter module (6), a speed and position monitoring module (7), a current fault diagnosis and reconstruction module (8), and a position and speed signal fault diagnosis and reconstruction module (9). The motor position sensor (3) is mounted on the motor shaft and is used to collect motor position signals; The speed and position monitoring module (7) is connected to the motor position sensor (3) and is used to convert the motor position signal into rotor angle θ and motor speed ω. e ; The position and speed signal fault diagnosis and reconstruction module (9) is connected to the speed and position monitoring module (7) to monitor and determine whether the motor position sensor (3) has failed. When the motor position sensor fails, it is used to reconstruct the motor position signal. The current sensor (1) is installed on the three-phase power line of the motor to collect the two-phase input current i of the motor. a and i b ; The current fault diagnosis and reconstruction module (8) is connected to the current sensor (1) and is used to determine whether the current sensor has failed. When a failure occurs, it is used to reconstruct the two-phase current signal output by the motor. The current fault diagnosis and reconstruction module (8) is connected to the position and speed signal fault diagnosis and reconstruction module (9) and is used to output the two-phase current signal of the motor required for position and speed signal reconstruction. The current fault diagnosis and reconstruction module (8) is connected to the motor control algorithm module (5) and is used to output the two-phase current signal i required by the motor control algorithm. a_out and i b_out ; The position speed signal fault diagnosis and reconstruction module (9) is connected to the motor control algorithm module (5) and is used to output the motor speed signal ω required by the motor control algorithm. e_out and rotor angle θ out ; The three-phase voltage sensor (2) is installed on the three-phase power lines of the motor and is used to collect the three-phase AC voltage u of the motor. a u b and u c ; The Clarke voltage inverter module (6) is connected to the three-phase voltage sensor (2) and is used to convert the three-phase AC voltage u a u b and u c Transformed into a two-phase AC voltage u α and u β ; The current fault diagnosis and reconstruction module (8) is connected to the Clarke voltage inverter module (6) for reconstructing the current signal and outputting the reconstructed two-phase motor current to the motor control algorithm module (5). The motor control algorithm module (5) uses the feedback motor speed signal ω e_out Rotor angle θ out The two-phase output current i of the motor a_out , and i b_out At the same time, combined with the given speed ω of the motor, six SVPWM signals are output to drive the inverse converter module (4). The inverse converter module (4) converts DC power into three-phase AC power to provide power to the motor.

2. The motor redundancy control system for a manned electric helicopter according to claim 1, characterized in that, The Clarke voltage inverter module (6) converts the three-phase AC voltage into a two-phase AC voltage according to the following formula: （1） Among them, u α and u β These are the two-phase AC voltages of the motor in the α and β coordinate systems, u. a u b and u c This is the three-phase input voltage for the motor.

3. A redundant motor control system for a manned electric helicopter according to claim 1, characterized in that, The current fault diagnosis and reconfiguration module (8) performs current reconfiguration according to the current sensor failure control strategy, and outputs the reconfigured two-phase motor current signals i and i, respectively. a_out = and i b_out = ; The failure control strategy for the current sensor is as follows: The voltage loop equation of the stator of a permanent magnet synchronous motor in the α and β phase coordinate systems can be expressed as follows: （2） Among them, u α and u β These are the voltages of the stator of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively; i α and i β These are the stator currents of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively; R s For stator resistance; L s For stator impedance; e α and e β These are the back electromotive forces of the stator of the permanent magnet synchronous motor in the α and β two-phase coordinate systems, respectively; The back electromotive force of the stator of a permanent magnet synchronous motor in the α and β two-phase coordinate systems can be expressed as: （3） Among them, Ψ f For permanent magnet flux linkage; p n ω is the number of magnetic pole pairs; e θ is the motor speed; θ is the motor rotor angle. Based on equations (2) and (3), an observer of the following form is designed: （4） Where G is the observer gain matrix, which can be determined based on the operating load characteristics of the manned electric helicopter; ω e~ The motor speed signal from the previous sampling period; θ ~ The rotor angle of the motor in the previous sampling period is denoted by J; J is the moment of inertia of the motor, which can be approximated as a constant; T is the rotor angle of the motor in the previous sampling period. l For the motor load torque, the load torque of a manned electric helicopter at a given rotor speed can be approximated as a constant; F v i is the coefficient of viscous friction of the motor, which can be approximated as a constant; α and i β These are the observed values ​​of the motor stator current; According to the observer in equation (4), the stator current i of the motor is observed. α and i β The estimated values ​​of the three-phase stator currents of the motor can be obtained by performing an inverse Clarke transform. a and b This completes the reconfiguration of the stator current; （5）。 4. A redundant motor control system for a manned electric helicopter according to claim 1, characterized in that, The current fault diagnosis and reconstruction module (8) determines whether a current sensor failure has occurred using the current sensor fault diagnosis method. If no current sensor failure has occurred, but the motor position sensor has failed, the position and speed signal fault diagnosis and reconstruction module (9) reconstructs the motor position and speed signal according to the motor position and speed signal reconstruction method and outputs the reconstructed motor speed ω. e_out = and rotor angle θ out = ; This represents the estimated rotor angle. The current sensor fault diagnosis method is as follows: Since the instantaneous sum of the three-phase stator currents of the motor is zero, dual current sensors are used, respectively arranged on phases a and b. To detect current sensor faults, the current values ​​collected by the current sensors are compared with the current information collected in the previous sampling cycle, and the difference is calculated. （6） Where, Δi a The current difference between phase a and phase i; a~ and i b~ The value is the sampled value of the current sensor in the previous sampling period; Δi b This represents the current difference between phase b. During the cruise of the manned electric helicopter, the motor working phase current will not change abruptly within adjacent sampling periods. Given the maximum allowable error current setting threshold Δi0 for the manned electric helicopter motor, when the current difference between phase a and phase b exceeds the threshold Δi0, it can be determined that the current sensor is faulty and the motor stator current needs to be reconstructed. The current fault diagnosis and reconstruction module (8) outputs the current that satisfies: （7） Among them, i a_out and i b_out These are the phase a and phase b currents of the permanent magnet synchronous motor output by the current fault diagnosis and reconfiguration module (8), respectively. and The estimated currents for phase a and phase b are respectively.

5. A redundant motor control system for a manned electric helicopter according to claim 1, characterized in that, The position and speed signal fault diagnosis and reconstruction module (9) reconstructs the motor position and speed signal according to the motor position and speed signal reconstruction method, and outputs the reconstructed motor speed ω. e_out = and rotor angle θ out = ; Given the two-phase current i of the permanent magnet synchronous motor a_out and i b_out The stator current of a permanent magnet synchronous motor in the α and β phase coordinate systems can be expressed as: （8） Among them, i α and i β These are the stator currents of the permanent magnet synchronous motor in the α and β phase coordinate systems, respectively. According to sliding mode theory, the back electromotive force of the stator of a permanent magnet synchronous motor in the α and β two-phase coordinate systems can be expressed as a switching function of the independent variable: （9） Where k is the modulation coefficient, which can be obtained from the load characteristics of the manned electric helicopter motor; i α~ and i β~ These are the sampled values ​​of the motor stator current obtained in the previous sampling period; and i represents the difference between the measured and estimated current values ​​in the α and β phase coordinate systems. a~ and i b~ This is the sampled value from the previous sampling period of the current sensor; The back electromotive force in equation (9) is filtered using a low-pass filter to remove high-frequency observation noise from the back electromotive force: （10） Where, ω c e is the cutoff frequency of the low-pass filter. α and e β These are the filtered back electromotive forces of the permanent magnet synchronous motor stator in the α and β two-phase coordinate systems, respectively; E α and E β This is the back electromotive force in a two-phase coordinate system; From equations (3) and (10), we can obtain （11） in, and These are the estimated values ​​for motor speed and rotor angle, respectively.

6. A redundant motor control system for a manned electric helicopter according to claim 1, characterized in that, The position and speed signal fault diagnosis and reconstruction module (9) determines whether a motor position sensor failure has occurred based on the motor position sensor fault diagnosis method; if no motor position sensor failure has occurred, it outputs the motor rotor angle θ and speed ω. e , to the motor control algorithm module (5); If the motor position sensor fails, the current sensor will collect the two-phase current signals i from the motor. a_out and i b_out Reconstruct the motor position and speed signals; The fault diagnosis method for the motor position sensor is as follows: The maximum permissible error threshold for the motor rotor angle is set as follows: When the maximum permissible error value of the motor rotor angle exceeds the threshold If the position sensor fails, the motor rotor angle needs to be reconstructed. The position and speed signal fault diagnosis and reconstruction module (9) outputs the motor rotor angle and speed, which meet the following requirements: （12） Where, θ ~ θ is the sampled value of the motor rotor angle in the previous sampling period; out and ω e_out These are the reconstructed output values ​​of the motor rotor angle and speed, respectively. This is an estimated value for the rotor angle.

7. A redundant motor control system for a manned electric helicopter according to claim 1, characterized in that, When both the current sensor (1) and the motor position sensor (3) are diagnosed as faulty, the position and speed signal fault diagnosis and reconstruction module (9) calculates the current signal i output by the motor fault diagnosis and reconstruction module (8) in the previous sampling cycle. a~ and i b~ Perform motor position signal reconstruction and output motor rotor angle θ out and rotational speed ω e_out The motor control algorithm module (5) outputs the rotor angle and motor speed signals required by the motor control algorithm; the motor fault diagnosis and reconstruction module (8) outputs the motor rotor angle θ from the previous sampling period based on the position and speed signals from the fault diagnosis and reconstruction module (9). ~ Perform motor current signal reconstruction and output two-phase motor current signals i. a_out and i b_out The motor control algorithm module (5) is used to output the two-phase current signals of the motor required by the motor control algorithm.

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