System and method for axle torque safe electric vehicle

Abstract

The present application relates to systems and methods for axle torque safe electric vehicles. A torque safety system for a vehicle is provided. The system receives a signal from a sensor coupled to a motor shaft of an electric motor and determines an acceleration of the electric motor based on a signal from the sensor indicating an amount of rotation of the motor shaft. The system determines an internal torque between the motor shaft and an input gear coupled to the motor shaft based on the acceleration of the electric motor and the inertia of the electric motor and the gearbox. The powertrain of the vehicle includes the gearbox and the electric motor, and the input gear couples the electric motor to the gearbox. The system determines whether the internal torque exceeds a threshold torque, and in response to determining that the internal torque exceeds the threshold torque, the system reduces power output to the electric motor. The system also diagnoses the health of the gearbox.

Description

Summary of the Invention

[0001] It is advantageous to provide a torque security system in a vehicle powered by an electric motor (e.g., a hybrid vehicle or an electric vehicle) by monitoring the torque output by the electric motor to prevent over-torque conditions in which the motor shaft of the electric motor or other components of the powertrain (e.g., the electric motor and the drivetrain) may be damaged. For example, if the torque security system detects an over-torque condition (e.g., exceeding the torque rating of the motor shaft), it is advantageous to reduce power to the electric motor (e.g., by torque limiting the electric motor) before damage occurs to the motor shaft of the electric motor or other components of the powertrain.

[0002] In one approach, the system estimates the motor shaft torque (e.g., the torque output by the electric motor) based on the output of sensors (e.g., rotation sensors) mounted on the wheels of the vehicle. However, in this approach, the system may not be able to accurately estimate the motor shaft torque or detect certain oscillations due to gear latching and gearbox damping introduced by the gearbox coupled to the electric motor. As a result, the powertrain may be damaged (e.g., a broken motor shaft). Additionally, in this approach, the system may not be able to detect an over-torque condition quickly enough to prevent damage to the powertrain. Still further, in this approach, the system may not be able to diagnose damage to the gearbox during operation (e.g., a broken tooth on an input gear coupled to the motor shaft).

[0003] Therefore, in some embodiments, it would be advantageous to provide a system that quickly detects certain oscillation and over-torque conditions and reduces power to the electric motor to prevent powertrain damage. Additionally, in some embodiments, it would be advantageous to provide a system that can diagnose gearbox damage (e.g., a damaged input gear).

[0004] In order to address one or more of these problems, a torque safety system and a vehicle including the torque safety system are provided. The torque safety system monitors a signal from a sensor coupled to a motor shaft of an electric motor and determines the acceleration of the electric motor based on the monitored signal. The sensor indicates the amount of rotation of the electric motor. The system determines the internal torque between the motor shaft and an input gear coupled to the motor shaft based on the acceleration of the electric motor and the inertia of the electric motor and the gearbox. The powertrain of the vehicle includes the gearbox and the electric motor, and the input gear couples the electric motor to the gearbox. The system determines whether the internal torque exceeds a threshold torque. In response to determining that the internal torque exceeds the threshold torque, the system reduces the power output to the electric motor. By quickly reducing the power output to the electric motor, damage to the powertrain can be prevented.

[0005] In some embodiments, the system may perform an emergency shutdown to reduce power output to the electric motor by reducing the power output to zero.

[0006] In some embodiments, the system may reduce power output to the electric motor by reducing the output of an inverter driving the electric motor.

[0007] In some embodiments, the system can determine the internal torque by determining the acceleration of the motor multiplied by the inertia of the motor and the gearbox.

[0008] In some embodiments, the threshold torque may include a first threshold torque and a second threshold torque. The system may determine whether the internal torque exceeds the threshold torque by determining whether the internal torque exceeds a first threshold torque (e.g., a shutoff torque threshold). In response to determining that the internal torque exceeds the first threshold torque, the system may determine that the internal torque exceeds the threshold torque. In response to determining that the internal torque does not exceed the first threshold torque, the system may determine whether the internal torque exceeds a second threshold torque (e.g., a conditional shutoff torque threshold) for at least a threshold number of consecutive cycles. In response to determining that the internal torque exceeds the second threshold torque for at least a threshold number of consecutive cycles, the system may determine that the internal torque exceeds the threshold torque. In response to determining that the internal torque does not exceed the second threshold torque for at least a threshold number of consecutive cycles, the system may determine that the internal torque does not exceed the threshold torque.

[0009] In some embodiments, the first threshold torque may be greater than the second threshold torque.

[0010] In some embodiments, the system may determine the speed of the motor based on a signal from the resolver and may determine whether the speed of the motor is constant. In response to determining that the speed of the motor is constant, the system may convert the acceleration of the motor into the frequency domain, may filter the converted acceleration using a bandpass filter, and may determine whether the input gear is damaged based on the output of the bandpass filter.

[0011] In some embodiments, the system can set the parameters of the bandpass filter based on the speed of the motor and the number of teeth on the input gear.

[0012] In some embodiments, the system can determine whether the input gear is damaged by determining whether a harmonic of the bandpass filter output corresponding to the number of teeth on the input gear exceeds a threshold. In some embodiments, in response to determining that the harmonic of the bandpass filter output exceeds the threshold, the system can determine that the input gear is damaged. In some embodiments, in response to determining that the input gear is damaged, the system can generate a notification of the damaged input gear for output.

[0013] In some embodiments, the threshold torque may correspond to a torque limit of the motor shaft (eg, a maximum torque that may be applied to the motor shaft before the motor shaft is damaged). BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The foregoing and other objects and advantages of the present disclosure will become apparent upon consideration of the following detailed description taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts throughout, and wherein:

[0015] Figure 1 shows a block diagram of an exemplary powertrain according to some embodiments of the present disclosure;

[0016] Figure 2 According to some embodiments of the present disclosure Figure 1 an exploded view of one of the electric motors and gearboxes of the powertrain;

[0017] Figure 3 shows a block diagram of an exemplary system according to some embodiments of the present disclosure;

[0018] Figure 4 A flowchart illustrating an exemplary process for implementing a torque safety application according to some embodiments of the present disclosure is shown;

[0019] Figure 5 A flowchart illustrating an exemplary process for determining whether the input torque exceeds a torque threshold according to some embodiments of the present disclosure is shown;

[0020] Figure 6 A flowchart illustrating an exemplary process for implementing a torque safety application according to some embodiments of the present disclosure is shown;

[0021] Figure 7 A flowchart illustrating an exemplary process for implementing a torque safety application according to some embodiments of the present disclosure; and

[0022] Figure 8 Graphs showing input gear harmonics in the frequency domain according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0023] Figure 1 A block diagram of an exemplary powertrain 100 according to some embodiments of the present disclosure is shown. As shown, powertrain 100 includes motors 101 and 102, gearboxes 103 and 104, axles 105 and 106, and wheels 107 and 108. As shown, each of motors 101 and 102 drives a corresponding one of wheels 107 and 108. For example, motor 102 can be coupled to gearbox 104 and drive wheel 108 via axle 106. However, this is merely an example, and a single motor can drive multiple wheels. In some embodiments, wheels 107 and 108 can be front wheels or rear wheels.

[0024] Figure 2 According to some embodiments of the present disclosure Figure 1200 is an exploded view of one of the motors and gearboxes of the powertrain 100. As shown, the motor 102 includes a motor shaft 202 and an input gear 204 coupled to the motor shaft 202. As shown, the motor 102 can be surrounded by a housing 210. The input gear 204 transfers rotational energy from the motor 202 to a gear 206 of the gearbox 104. In some embodiments, the number of gears 206 is exemplary, and the gearbox 104 can include any number of gears 206. In some embodiments, a sensor (e.g., a resolver 208) can be coupled to the motor shaft 202 of the motor. In some embodiments, the resolver 208 can be a converter / electromagnetic transducer that measures the degree of rotation of the motor shaft 202. For example, the resolver 208 can be a rotary converter that includes a cylindrical rotor and a stator. Although a resolver is shown, any suitable sensor configured to measure the degree of rotation of the motor shaft 202 can be used.

[0025] Figure 3 300 , according to some embodiments of the present disclosure. As shown, the system 300 includes a motor 301, a control system 302, a user interface 303, and a parser 305. As shown, the control system 302 includes a control circuit 304, a communication interface 310, power electronics 312, a power supply 314, and one or more sensors 316. As shown, the motor 301 may include a motor shaft 307 and an input gear 309 coupled to the motor shaft 307 (e.g., as described above with reference to FIG. 301 ). Figure 2 The control circuit 304 includes a processor 306 and a memory 308. In an exemplary embodiment, the control system 302 can be used to monitor an over-torque condition and to generate an error signal when the powertrain (e.g., Figure 1 In some embodiments, the control system 302 can also be used to diagnose damage to the gearbox (e.g., Figure 1 Damage to the gearbox 103, 104).

[0026] Control circuitry 304 may include hardware, software, or both implemented on one or more modules configured to control the operation of motor 301 and implement a torque safety application. In some embodiments, processor 306 may include one or more processors, such as, for example, a central processing unit with a single or dual core, a bus, a logic circuit, an integrated circuit, a digital signal processor, a graphics processor, an embedded processing device, any other suitable component for reading and executing computer instructions, or any combination thereof. Memory 308 may include any suitable storage device, such as, for example, a volatile memory, a non-volatile memory, a removable storage device, a solid-state storage device, an optical device, a magnetic device, any other suitable component for storing and retrieving information, or any combination thereof. Communication interface 310 may include electrical terminals, a level shifter, a communication module, a connector, a cable, an antenna, any other suitable component for transmitting and receiving information, or any combination thereof. For example, communication interface 310 may include an Ethernet interface, a WiFi interface, an optical interface, a sensor interface (e.g., for interacting with one or more sensors 316), any other suitable wired or wireless interface, or any combination thereof. For illustration, communication interface 310 may include a sensor interface having a power supply, an analog-to-digital converter, a digital-to-analog converter, a signal processing device, a signal conditioning device, a connector, electrical terminals, any other suitable components for managing signals to and from the sensor, or any combination thereof. For further illustration, the sensor interface may be configured to communicate with resolver 305, a current sensor, a position sensor (e.g., a rotary encoder coupled to a motor shaft or gear shaft), a temperature sensor, a voltage sensor, an accelerometer (e.g., a vibration sensor), any other suitable sensor in sensor 316, or any combination thereof. In some embodiments, communication interface 310 is configured to transmit control signals indicative of motor commands to power electronics 312. The power electronics 312 may include an inverter, a motor drive, switches (e.g., IGBTs, MOSFETs, diodes (e.g., flyback diodes), one or more buses (e.g., a DC bus), any other suitable components arranged in any suitable configuration (e.g., an H-bridge, a half-bridge), or any combination thereof. The power supply 314 may include a battery, a battery system, leads coupled to a battery system, or a combination thereof for providing electrical power to components of the control system 302, any other suitable components, or any combination thereof.

[0027] The user interface 303 may include a display (e.g., a touch screen or touch-sensitive display) provided as a standalone device or integrated with other elements of the control system 302. A video or graphics card may be integrated with the control circuit 304 and may generate output to the user interface 303. In some embodiments, the user interface may display notifications (e.g., torque safety notifications) to a user (e.g., the driver of a vehicle).

[0028] In an exemplary embodiment, control system 302 can be configured to control motor 301. In some embodiments, motor 301 includes phases corresponding to windings, which are coupled to power electronics 312 via phase leads. In some such embodiments, power electronics 312 is configured to receive control signals from control circuit 304. Control circuit 304 can be configured to implement a motor control application based on computer instructions stored in memory 308, wherein the motor control application generates control signals based on one or more inputs. For example, control circuit 304 can be configured to implement a control scheme for generating a current command based on a desired performance (e.g., desired motor position, speed, acceleration, torque, flux, or a combination thereof), and can generate a control signal indicative of the current command. For illustration, the control signal can include a pulse width modulated (PWM) signal, a pulse density modulated (PDM) signal, an analog signal, a digital signal (e.g., via a serial or parallel interface), any other suitable signal type, or any combination thereof.

[0029] In an exemplary embodiment, control system 302 (e.g., or control circuit 304) may be configured to execute a torque safety application to detect an over-torque condition and reduce power to motor 301 (via power electronics 312) to prevent damage to the vehicle's powertrain. Control system 302 (e.g., or control circuit 304) may also be configured to execute the torque safety application to diagnose a condition and / or damage to input gear 309 of motor 301. Control system 302 (e.g., or control circuit 304) may also be configured to execute the torque safety application to display a notification to a user (e.g., a driver of the vehicle) (e.g., via user interface 303).

[0030] Figure 4 1 shows a flow chart of an exemplary process 400 for implementing a torque safety application according to some embodiments of the present disclosure. The process 400 may be performed by, for example Figure 3 The process 400 may be implemented using the control system 302 (e.g., or any aspect thereof), any other suitable system for executing computer instructions and generating control signals (e.g., a fault control signal), or any combination thereof. In some embodiments, it may be advantageous to implement the process 400 to diagnose an over-torque condition in approximately 1 ms or less.

[0031] Process 400 begins at step 402 when a torque safety application (e.g., via control circuit 304) monitors (e.g., via communication interface 310) a signal output by a resolver (e.g., resolver 305) that measures the number of degrees of rotation of a motor shaft (e.g., motor shaft 307) of a motor (e.g., motor 301). For example, control circuit 304 receives position information in the signal received from the resolver.

[0032] At step 404, the torque safety application (e.g., via the control circuit 304) determines the acceleration of the motor (e.g., the acceleration of the motor shaft of the motor) based on the signal received from the resolver. For example, in some embodiments, the control circuit 304 may implement a resolver-to-digital converter that converts the signal from the resolver into the angular position and velocity of the motor shaft of the motor. In some embodiments, the control circuit 304 may determine the acceleration based on the determined velocity (e.g., by taking the derivative of the determined velocity). However, this is merely an example, and the acceleration of the motor may be calculated using any suitable method. For example, the control circuit 304 may determine the acceleration using equation [1], where op is the zero-to-peak value of the signal output by the resolver, and frequency is the frequency of the signal. For example, using equation [1], if the frequency is 200 Hz and op is 50 radians / second, the control circuit 304 may determine the acceleration to be approximately 62,800 radians / second 2 .

[0033] Equation [1]

[0034] α=2π*freq*(o–p)

[0035] At step 406, the torque safety application program (eg, via the control circuit 304) applies a torque safety function based on the determined motor acceleration and the motor and gearbox (eg, Figure 2 The internal torque between the motor shaft of the motor and the input gear (e.g., input gear 309) coupled to the motor shaft is determined based on the inertia of the gearbox 104. For example, the internal torque can be calculated as the product of the determined acceleration and the inertia of the motor and the gearbox, as shown in the following equation [2].

[0036] Equation [2]

[0037] Internal_torque = α * inertia (电机和齿轮箱)

[0038] In some embodiments, the inertia of the motor and gearbox can be predetermined and stored in a memory (e.g., memory 308). The inertia of the motor and gearbox can be determined using any suitable method (e.g., by calculating the set of point masses in the motor and gearbox). For example, in an exemplary embodiment, the inertia of the motor and gearbox can be 0.02 kg*m 2 .

[0039] At step 408, the torque safety application (e.g., via the control circuit 304) determines whether the internal torque is greater than a torque threshold. The torque threshold may be predetermined based on the maximum torque specification of the powertrain (e.g., the maximum torque rating of the motor shaft of the electric motor). For example, in an exemplary embodiment, the torque threshold may be 350 Nm. The torque threshold may be stored in a memory (e.g., memory 308). As described in reference Figure 5 In more detail, in some embodiments, multiple torque thresholds may be used to compensate for noise in the signal from the resolver. If the control circuit 304 determines that the internal torque is not greater than the torque threshold ("No" at 408), the process 400 may return to step 402 and continue monitoring the signal output by the resolver. Otherwise, if the control circuit 304 determines that the internal torque is greater than the torque threshold ("Yes" at 408), the process 400 may proceed to step 410.

[0040] At step 410, the torque safety application (e.g., via the control circuit 304) reduces power to the motor (e.g., via the power electronics 312) (e.g., by torque limiting the motor). For example, in some embodiments, the control circuit 304 performs an emergency stop and reduces power to the motor to zero. However, in some embodiments, it may be advantageous to reduce power to the motor without performing an emergency stop. For example, the control circuit 304 may reduce power to the motor to a level at which the internal torque is less than a torque threshold (e.g., within the rated torque range). In some embodiments, it may be advantageous to provide a user with notification (e.g., via the user interface 303) that an emergency stop has been performed due to detection of an over-torque condition.

[0041] Figure 5 FIG. 4 is a flow chart illustrating an exemplary process 408A for determining whether the input torque exceeds a torque threshold according to some embodiments of the present disclosure. Figure 4 406. At step 502, the torque safety application (e.g., via the control circuit 304) determines whether the internal torque is less than a conditional shutoff torque threshold. The conditional shutoff torque threshold can be one of a plurality of different torque thresholds. For example, Figure 5As shown in FIG408 , two different torque thresholds (i.e., a “conditional shutoff torque threshold” and a “shutoff torque threshold”) may be used in process 408A. The different torque thresholds may be predetermined based on the maximum torque specification of the powertrain and the noise in the signal from the resolver. For example, if the signal from the resolver is distorted due to noise, then the torque threshold may be determined (e.g., in FIG408 ). Figure 4 The internal torque (at step 406) may be artificially high over one or more cycles. In this case, if a single torque threshold is used, an erroneous overtorque condition may be identified due to noise (e.g., resulting in an unnecessary shutdown). However, if the threshold torque is set to a higher value to avoid erroneous identification, the actual overtorque condition may not be correctly identified (e.g., an erroneous overtorque condition may be identified). To avoid this problem, different torque thresholds may be determined while still protecting the powertrain from damage caused by an actual overtorque condition. For example, a low threshold (e.g., a conditional shutdown torque threshold) may be set to be less than the powertrain's maximum torque specification. The low threshold may also be set based on an expected maximum possible distortion level of the signal from the resolver. In some embodiments, for an overtorque condition to be identified, the internal torque must exceed the conditional shutdown torque threshold for a predetermined number of consecutive cycles. The high threshold (e.g., the shutdown torque threshold) may be set to correspond to the powertrain's maximum torque specification. In some embodiments, an overtorque condition may be identified if the internal torque exceeds the shutdown torque threshold, for example, over one cycle. In some embodiments, it may be advantageous to include a buffer zone in the threshold to prevent the powertrain's maximum torque specification from being exceeded. Although two thresholds are discussed, any suitable number of thresholds may be used.

[0042] If the control circuit 304 determines that the internal torque is less than the conditional shutoff torque threshold ("YES" at 502), the process 408A determines that the over-torque condition does not exist and may return to (e.g., Figure 4 Otherwise, if the control circuit 304 determines that the internal torque is not less than the conditional shutoff torque threshold (“No” at 502 ), process 408A may proceed to step 502 .

[0043] At step 504, the torque safety application (e.g., via the control circuit 304) determines whether the internal torque is greater than the conditional shutoff torque threshold. If the control circuit 304 determines that the internal torque is greater than the conditional shutoff torque threshold ("yes" at 504), the process 408A proceeds to step 410, where the torque safety application determines that an over-torque condition exists and reduces power to the motor. Otherwise, if the control circuit 304 determines that the internal torque is not greater than the shutoff torque threshold ("no" at 502), the process 408A determines that an over-torque condition may exist (e.g., indeterminate), and the process 408A may proceed to step 506.

[0044] At step 506 , the torque safety application (eg, via control circuit 304 ) sets a counter equal to 1 (eg, “counter=1”), and process 408A may proceed to step 508 .

[0045] At step 508, the torque safety application (e.g., via the control circuit 304) determines the next internal torque value. For example, the process 408A may repeat steps 402, 404, and 406 to determine the next internal torque value (e.g., without resetting the counter value), and the process 408A may proceed to step 510.

[0046] At step 510, the torque safety application (e.g., via the control circuit 304) determines whether the internal torque is greater than the conditional shutoff torque threshold. If the control circuit 304 determines that the internal torque is greater than the conditional shutoff torque threshold ("Yes" at 510), process 408A proceeds to step 410, where the torque safety application determines that an over-torque condition exists and reduces power to the motor. Otherwise, if the control circuit 304 determines that the internal torque is not greater than the conditional shutoff torque threshold ("No" at 510), process 408A may proceed to step 512.

[0047] At step 512, the torque safety application (e.g., via the control circuit 304) determines whether the internal torque is greater than or equal to the conditional shutoff torque threshold. If the control circuit 304 determines that the internal torque is not greater than or equal to the conditional shutoff torque threshold and is less than or equal to the shutoff torque threshold ("No" at 512), the control circuit 304 determines that the over-torque condition does not exist, and the process 408A may return to (e.g., Figure 4 ) in step 402 and continue to monitor the signal output by sensor 316. Otherwise, if control circuit 304 determines that the internal torque is greater than or equal to the conditional shutoff torque threshold and less than or equal to the shutoff torque threshold (“YES” at 512), control circuit 304 determines that an overtorque condition may exist (e.g., indeterminate), and process 408A may proceed to step 514.

[0048] At step 514 , the torque safety application (eg, via control circuit 304 ) increments the counter by one, and process 408A may proceed to step 516 .

[0049] At step 516, the torque safety application (e.g., via the control circuit 304) determines whether the counter value is greater than a counter threshold. The counter threshold determines the number of consecutive internal torque values ​​that must satisfy the relationship in step 512 before the control circuit 404 identifies an overtorque condition. In some embodiments, the counter threshold is predetermined based on the expected noise in the signal from the resolver and how quickly the signal settles (e.g., in response to large accelerations). For example, in an exemplary embodiment, the counter threshold is set to ten. However, this is merely an example, and the counter threshold can be set to any suitable value. In some embodiments, the counter threshold is periodically updated based on noise detected in the signal from the resolver (e.g., during steady-state operation or during calibration). If the control circuit 304 determines that the counter value is greater than the counter threshold ("yes" at 516), the control circuit 304 determines that an overtorque condition exists, and process 408A can proceed to step 410. Otherwise, if the control circuit 304 determines that the counter value is greater than the counter threshold (“NO” at 516 ), the process 408A determines that an overtorque condition may exist (eg, indeterminate), and the process 408A may return to step 508 .

[0050] Referenced above Figure 4 and 5 In the torque safety application described herein, the determined internal torque (e.g., step 406) is compared to the torque thresholds (e.g., steps 408, 502, 504, 510, and 512) to determine if an over-torque condition exists. However, as described below with reference to Figure 6 As mentioned, in some embodiments, it may be advantageous to determine whether an overtorque condition exists based solely on the determined acceleration (eg, step 404 ), without determining the internal torque.

[0051] Figure 6 A flow chart of an exemplary process 600 for implementing a torque safety application according to some embodiments of the present disclosure is shown. Process 600 begins at step 602. Steps 602 and 604 correspond to Figure 4 Steps 402 and 404 are performed and are not described in detail here.

[0052] At step 606, the torque safety application (e.g., via the control circuit 304) determines whether the acceleration is greater than an acceleration threshold. The acceleration threshold can be predetermined based on the torque threshold discussed above in step 408 and the relationship set forth above in equation [2]. For example, as shown below in equation [3], by setting the internal torque in equation [3] equal to the torque threshold (e.g., predetermined based on the maximum torque specification of the powertrain), equation [2] can be rearranged to solve for the maximum allowable acceleration of the motor before an over-torque condition exists.

[0053] Equation [3]

[0054]

[0055] For example, in the exemplary embodiment, if the torque threshold is 350 Nm and the inertia of the motor and gearbox is 0.02 kg*m 2 , the acceleration threshold can be set to 17,500 rad / s 2 .

[0056] If the control circuit 304 determines that the acceleration is not greater than the acceleration threshold ("No" at 606), the process 600 may return to step 602 and continue to monitor the signal output by the resolver. Otherwise, if the control circuit 304 determines that the acceleration is greater than the acceleration threshold ("Yes" at 606), the control circuit 304 determines that an overtorque condition may exist and the process 600 may proceed to step 608. Step 608 corresponds to Figure 4 Step 410 is performed and will not be described in detail here.

[0057] In some cases, the teeth of the input gear coupled to the motor shaft of the electric motor may become damaged (e.g., due to wear under repeated high-torque conditions). Therefore, in some embodiments, it may be advantageous to determine the health of the gearbox. In an exemplary embodiment, the control system 302 (e.g., or the control circuit 304) may be configured to execute a torque safety application to diagnose damage to the gearbox and provide a notification to a user (e.g., a vehicle driver) regarding the health of the gearbox (e.g., via the user interface 303).

[0058] Figure 7 FIG2 shows a flow chart of an exemplary process 700 for implementing a torque safety application according to some embodiments of the present disclosure. The process 700 may be performed by, for example, Figure 3 It may be implemented by the control system 302 (eg, or any aspect thereof), any other suitable system for executing computer instructions and generating notifications, or any combination thereof.

[0059] Process 700 begins at step 702 when the torque safety application (e.g., via control circuit 304) monitors (e.g., via communication interface 310) a signal output by a resolver (e.g., resolver 305) that measures the number of degrees of rotation of a motor shaft (e.g., motor shaft 307) of a motor (e.g., motor 301). For example, step 702 corresponds to Figure 4 Step 402 is performed and will not be described in detail here.

[0060] At step 704, the torque safety application (e.g., via the control circuit 304) determines the motor speed of the motor based on the signal from the resolver. For example, the control circuit 304 calculates the angular velocity of the motor shaft. In some embodiments, based on the determined acceleration (e.g., Figure 4 It may be advantageous to determine the motor speed using the method of FIG. 4 (determined in step 404). However, any suitable method may be used.

[0061] At step 706, the torque safety application (e.g., via the control circuit 304) determines whether the motor speed is constant. For example, the control circuit 304 may periodically implement process 700 (e.g., when cruise control is set and the vehicle's speed is constant). If the control circuit 304 determines that the motor speed is not constant ("No" at 706), the process 700 may return to step 704. Otherwise, if the control circuit 304 determines that the motor speed is constant ("Yes" at 706), the process 700 may proceed to step 708. In some embodiments, the control circuit 304 may determine that the motor speed is constant if the motor speed is within a predetermined range.

[0062] At step 708, the torque safety application (eg, via the control circuit 304) determines the acceleration of the motor based on the signal received from the resolver. For example, step 708 corresponds to Figure 4 Step 406 is performed and will not be described in detail here.

[0063] At step 710, the torque safety application (e.g., via the control circuit 304) sets the parameters of the bandpass filter based on the motor speed (e.g., from step 704) and the number of teeth on the input gear (e.g., input gear 309) coupled to the motor shaft of the electric motor. For example, if the input gear has forty teeth, the control circuit 304 sets the parameters of the bandpass filter to capture the fortieth harmonic.

[0064] At step 712, the torque safety application (e.g., via the control circuit 304) filters the acceleration of the motor using a bandpass filter to retrieve the input gear harmonics. In some embodiments, instead of using a bandpass filter in steps 710 and 712, as shown in FIG. Figure 8As described in , it may be advantageous to convert the portion of the signal corresponding to the desired harmonics into the frequency domain (eg, using a Fourier transform) and identify the input gear harmonics in the frequency domain.

[0065] At step 714, the torque safety application (e.g., via the control circuit 304) determines whether any of the input gear harmonics exceed a threshold. For example, if a tooth on the input gear is damaged or missing, the input gear harmonics (e.g., corresponding to the number of teeth on the input gear) will exceed a predetermined threshold. The threshold may be predetermined (e.g., to filter out any noise) and stored in memory (e.g., memory 308). If the control circuit 304 determines that the input gear harmonics do not exceed the threshold ("No" at 714), the control circuit 304 determines that the gearbox is healthy, and the process 700 may proceed to step 716. Otherwise, if the control circuit 304 determines that the input gear harmonics do exceed the threshold ("Yes" at 714), the control circuit 304 determines that the gearbox is damaged (e.g., the input gear is damaged) and may proceed to step 718.

[0066] At step 716, the torque safety application outputs a notification of the gearbox health (e.g., via the control circuit 304). For example, the control circuit 304 may output a notification to the user (e.g., via the user interface 303). For example, the user interface 303 may display a message notifying the user of the gearbox health.

[0067] At step 718, the torque safety application outputs a notification of gearbox damage (e.g., via the control circuit 304). For example, the control circuit 304 may output a notification to the user (e.g., via the user interface 303). For example, the user interface 303 may display a message notifying the user that the gearbox is damaged and advising the user to stop driving immediately and repair the vehicle. In some embodiments, an emergency stop (e.g., Figure 4 In some embodiments, it may be advantageous to send a copy of the notification to, for example, the vehicle manufacturer, a maintenance shop associated with the vehicle, a vehicle dealer, etc. In some embodiments, it may be advantageous to store a copy of the notification in a vehicle logbook (e.g., in memory 308) along with any technical data.

[0068] Figure 8 Graphs 800, 801 show input gear harmonics in the frequency domain according to some embodiments of the present disclosure. As set out above, analysis of the converted acceleration signal in the frequency domain may be used instead of Figure 7712 . Curve 800 illustrates retrieved input gear harmonics 802a (e.g., the 40th harmonic) for an undamaged input gear 804a (e.g., having all 40 teeth). As shown, input gear harmonics 802a do not exceed threshold 806 (e.g., "No" at step 714). Curve 801 illustrates retrieved input gear harmonics 802b (e.g., the 40th harmonic) for a damaged input gear 804b (e.g., missing teeth). As shown, input gear harmonics 802b exceed threshold 806 (e.g., "Yes" at step 714), indicating damage to the input gear. In some embodiments, although an input gear having 40 teeth is described, process 700 can be used to diagnose the health of other gears in a gearbox having any number of teeth.

[0069] The foregoing is merely an example of the principles of the present disclosure, and various modifications may be made by those skilled in the art without departing from the scope of the present disclosure. The above embodiments are presented for purposes of illustration and not limitation. The present disclosure may also take many forms other than those explicitly described herein. Therefore, it is emphasized that the present disclosure is not limited to the methods, systems, and apparatus explicitly disclosed, but is intended to encompass variations and modifications thereof within the spirit of the following claims.

Claims

1. A method for protecting a powertrain of a vehicle, the method comprising: monitoring a signal from a sensor coupled to a motor shaft of an electric motor, wherein the sensor indicates an amount of rotation of the motor shaft; determining an acceleration of the motor based on a signal from the sensor; determining an internal torque between the motor shaft and an input gear coupled to the motor shaft based on an acceleration of the motor and an inertia of the motor and a gearbox, wherein a powertrain of the vehicle includes the gearbox and the motor, and the input gear couples the motor to the gearbox; determining whether the internal torque exceeds a threshold torque; as well as reducing power output to the electric motor in response to determining that the internal torque exceeds the threshold torque; The method further comprises: determining a speed of the motor based on a signal from the sensor; determining whether the speed of the motor is constant; and In response to determining that the speed of the motor is constant: filtering the acceleration of the motor using a bandpass filter; and It is determined whether the input gear is damaged based on an output of the bandpass filter. 2 . The method of claim 1 , wherein said reducing power output to said electric motor comprises performing an emergency shutdown by reducing said power output to zero. 3 . The method of claim 1 , wherein the reducing power output to the electric motor comprises reducing an output of an inverter driving the electric motor. 4 . The method of claim 1 , wherein said determining said internal torque comprises determining an acceleration of said motor multiplied by an inertia of said motor and said gearbox.

5. The method according to claim 1, wherein: The threshold torque includes a first threshold torque and a second threshold torque; The determining whether the internal torque exceeds the threshold torque includes: determining whether the internal torque exceeds the first threshold torque; in response to determining that the internal torque exceeds the first threshold torque, determining that the internal torque exceeds the threshold torque; in response to determining that the internal torque does not exceed the first threshold torque, determining whether the internal torque exceeds the second threshold torque for at least a threshold number of consecutive cycles; In response to determining that the internal torque exceeds the second threshold torque for at least the threshold number of consecutive cycles, determining that the internal torque exceeds the threshold torque; and In response to determining that the internal torque has not exceeded the second threshold torque for at least the threshold number of consecutive cycles, it is determined that the internal torque has not exceeded the threshold torque. The method of claim 5 , wherein the first threshold torque is greater than the second threshold torque. 7 . The method of claim 1 , further comprising setting parameters of the bandpass filter based on a speed of the motor and a number of teeth on the input gear.

8. The method of claim 7, wherein said determining whether said input gear is damaged comprises determining whether a harmonic of said bandpass filter output corresponding to a number of teeth on said input gear exceeds a threshold; In response to determining that the harmonics of the bandpass filter output exceed the threshold, determining that the input gear is damaged; as well as In response to determining that the input gear is damaged, a notification of the input gear being damaged is generated for output. 9 . The method of claim 1 , wherein the threshold torque corresponds to a torque limit of the motor shaft.

10. A system for protecting a vehicle powertrain, the system comprising: An input circuit, the input circuit being configured to: receiving a signal from a sensor coupled to a motor shaft of an electric motor, wherein the sensor indicates an amount of rotation of the motor shaft; A control circuit, the control circuit being configured to: determining an acceleration of the motor based on a signal from the sensor; determining an internal torque between the motor shaft and an input gear coupled to the motor shaft based on acceleration of the motor and inertia of the motor and a gearbox, wherein a powertrain of the vehicle includes the gearbox and the motor, and the input gear couples the motor to the gearbox; determining whether the internal torque exceeds a threshold torque; and reducing power output to the electric motor in response to determining that the internal torque exceeds the threshold torque; The control circuit is further configured to: determining a speed of the motor based on a signal from the sensor; determining whether the speed of the motor is constant; and In response to determining that the speed of the motor is constant: filtering the acceleration of the motor using a bandpass filter; and It is determined whether the input gear is damaged based on an output of the bandpass filter.

11. The system of claim 10, wherein the control circuit is further configured to perform an emergency shutdown by reducing the power output to the electric motor when reducing the power output to the electric motor.

12. The system of claim 10, wherein the control circuit is further configured to reduce an output of an inverter driving the electric motor when the power output to the electric motor is reduced.

13. The system of claim 10, wherein the control circuit is further configured to determine the product of the acceleration of the motor and the inertia of the motor and the gearbox when determining the internal torque.

14. The system of claim 10, wherein: The threshold torque includes a first threshold torque and a second threshold torque; and The control circuit is further configured to, when determining whether the internal torque exceeds the threshold torque: determining whether the internal torque exceeds the first threshold torque; in response to determining that the internal torque exceeds the first threshold torque, determining that the internal torque exceeds the threshold torque; in response to determining that the internal torque does not exceed the first threshold torque, determining whether the internal torque exceeds the second threshold torque for at least a threshold number of consecutive cycles; determining that the internal torque exceeds the threshold torque in response to determining that the internal torque exceeds the second threshold torque for at least the threshold number of consecutive cycles; as well as In response to determining that the internal torque has not exceeded the second threshold torque for at least the threshold number of consecutive cycles, it is determined that the internal torque has not exceeded the threshold torque. 15 . The system of claim 14 , wherein the first threshold torque is greater than the second threshold torque.

16. The system of claim 10, wherein the control circuit is further configured to set parameters of the bandpass filter based on a speed of the motor and a number of teeth on the input gear.

17. The system of claim 16, wherein: The control circuit is further configured to, when determining whether the input gear is damaged, determine whether a harmonic of the bandpass filter output corresponding to the number of teeth on the input gear exceeds a threshold; and The control circuit is further configured to: determining that the input gear is damaged in response to determining that a harmonic of the output of the bandpass filter exceeds the threshold; as well as In response to determining that the input gear is damaged, a notification of the input gear being damaged is generated for output.

18. A vehicle comprising: an electric motor comprising a motor shaft and an input gear coupled to the motor shaft; power electronics configured to output power to the electric motor; a gearbox, wherein the input gear couples the electric motor to the gearbox; a sensor coupled to the motor shaft and configured to output a signal indicative of an amount of rotation of the motor shaft; an input circuit configured to receive the signal from the sensor; as well as A control circuit, the control circuit being configured to: determining an acceleration of the motor based on a signal from the sensor; determining an internal torque between the motor shaft and the input gear based on an acceleration of the motor and an inertia of the motor and the gearbox; determining whether the internal torque exceeds a threshold torque; as well as in response to determining that the internal torque exceeds the threshold torque, controlling the power electronics to reduce power output to the electric motor; The control circuit is further configured to: determining a speed of the motor based on a signal from the sensor; determining whether the speed of the motor is constant; and In response to determining that the speed of the motor is constant: filtering the acceleration of the motor using a bandpass filter; and It is determined whether the input gear is damaged based on an output of the bandpass filter.

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