Eccentricity detection system

Abstract

An eccentricity detection system includes a vibration eccentricity module configured to determine the vibration eccentricity of the electric motor based on vibration measured during motor operation; an inductance eccentricity module configured to determine the inductance eccentricity of the electric motor based on a curve of the incremental inductance of the electric motor; and a fault module configured to indicate, based on both (a) the vibration eccentricity of the electric motor and (b) the inductance eccentricity of the electric motor, whether the electric motor contains an eccentricity fault.

Description

INITIATIONThe information provided in this section is for the purpose of generally presenting the context of the disclosure. Both the work of the presently named inventors to the extent it is described in this section and the aspects of the description that cannot otherwise qualify as prior art at the time of filing are neither expressly nor impliedly admitted as prior art against the present disclosure.The present disclosure relates to electric motors, and more particularly to systems and methods for detecting air gap and eccentricity errors of electric motors, such as vehicles.Some types of vehicles include only one internal combustion engine that generates drive torque. Electric vehicles may not include an internal combustion engine and may rely on one or more electric motors to drive.Hybrid vehicles include both an internal combustion engine and one or more electric motors. Some types of hybrid vehicles use the electric motor and the engine in an effort to achieve higher fuel efficiency than if only the engine was used. Some types of hybrid vehicles use the electric motor and the engine to achieve a higher torque output than that which the engine alone could achieve.Some example types of hybrid vehicles include parallel hybrid vehicles, series hybrid vehicles, and other types of hybrid vehicles. In a parallel hybrid vehicle, the electric motor operates in parallel with the engine to combine the power and range advantages of the engine with the efficiency and regenerative braking advantages of the electric motors. In a series hybrid vehicle, the engine drives a generator to generate electricity for the electric motor, the electric motor driving a transmission. This allows the electric motor to take over some of the power responsibilities of the engine, enabling the use of a smaller and possibly more efficient engine.WO 2011 / 006 528 A1 discloses a method for detecting faults in a rotating electrical machine. For fault detection, a signal, e.g. a stator current or a mechanical oscillation of the electric machine, is measured. This signal is divided into frequency bands. By analyzing the time evolution of these frequency bands, a plurality of fault conditions are identified. From KR 10 1 210 825 B1 a device for diagnosing demagnetization of a permanent magnet in a permanent magnet synchronous motor is known.SUMMARYAccording to one feature, an eccentricity detection system includes a vibration eccentricity module configured to determine a vibration eccentricity of the electric motor based on a vibration of the electric motor measured during operation of the motor; an inductance eccentricity module configured to determine an inductance eccentricity of the electric motor based on a curve of the incremental inductance of the electric motor; and an error module configured to indicate whether the electric motor includes an eccentricity error based on both (a) the vibration eccentricity of the electric motor and (b) the inductance eccentricity of the electric motor.In further features, the error module is configured to selectively indicate that the electric motor has an eccentricity error when the vibration eccentricity is greater than a predetermined value.In further features, the error module is configured to selectively indicate that the electric motor has an eccentricity error when the inductance eccentricity is greater than a predetermined value.In further features, a voltage eccentricity module is configured to determine a voltage eccentricity of the electric motor based on a voltage command for the electric motor, wherein the fault module is configured to further indicate whether the electric motor includes an eccentricity fault based on the voltage eccentricity.In further features, the error module is configured to selectively indicate that the electric motor has an eccentricity error when the voltage eccentricity is greater than a predetermined value.In further features, the voltage command is a d-axis voltage command.In further features, the voltage command is a q-axis voltage command.In further features, the voltage eccentricity module is configured to determine the voltage eccentricity of the electric motor when the electric motor is operating at a predetermined speed.In further features, the voltage eccentricity module is configured to determine the voltage eccentricity of the electric motor when the electric motor is operating at a predetermined torque.In further features, the vibration eccentricity module is configured to determine the vibration eccentricity of the electric motor when the electric motor is operating at a predetermined speed.In further features, the vibration eccentricity module is configured to determine the vibration eccentricity of the electric motor based on an amplitude of the vibration of the electric motor at a predetermined frequency.In further features, the inductance eccentricity module is configured to determine the inductance eccentricity of the electric motor based on a d-axis current of the electric motor at a predetermined point on the incremental inductance curve of the electric motor.In further features, the predetermined point is a peak of the incremental inductance curve.In further features, the peak is a second highest peak of the incremental inductance curve.In further features, the inductance eccentricity module is configured to determine the inductance eccentricity of the electric motor when a d-axis current of the electric motor is set to a predetermined maximum current.In further features, the error module is configured to indicate that the electric motor includes an eccentricity error when both (a) the oscillation eccentricity of the electric motor is greater than a predetermined value and (b) the inductance eccentricity of the electric motor is less than a second predetermined value.In further features, the error module is configured to selectively indicate that the electric motor includes an eccentricity error when the vibration eccentricity of the electric motor is greater than a predetermined value and the inductance eccentricity of the motor is greater than a second predetermined value.In further features, the error module is configured to selectively indicate that the electric motor includes an eccentricity error when the inductance eccentricity of the electric motor is greater than a predetermined value and the vibration eccentricity of the motor is less than a second predetermined value.In further features, the error module is configured to selectively indicate that the electric motor includes an eccentricity error when the inductance eccentricity of the electric motor is greater than a predetermined value, the vibration eccentricity of the motor is less than a second predetermined value, and an amplitude of the vibration at a frequency is less than a third value.According to an un-claimed feature, an eccentricity detection method includes: determining an oscillation eccentricity of the electric motor based on an oscillation of the electric motor measured during operation of the motor; determining an inductance eccentricity of the electric motor based on a curve of the incremental inductance of the electric motor; and indicating whether the electric motor includes an eccentricity error based on both (a) the oscillation eccentricity of the electric motor and (b) the inductance eccentricity of the electric motor.Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings. The detailed description and specific examples are provided for illustrative purposes only and are not intended to limit the scope of the disclosure.BRIEF DESCRIPTION OF THE DRAWINGSThe present disclosure will be more fully understood from the detailed description and the accompanying drawings, in which: FIG. 1 is a functional block diagram of an example vehicle system; FIG. 2 is a functional block diagram of an exemplary drive control system; FIG. 3 is a diagram including an example implementation of a power control system; FIG. 4 is a diagram of an example implementation of an inverter module; FIG. 5 is a functional block diagram of an example motor control module; FIG. 6 is a functional block diagram of an error detection system; FIG. 7 is a functional block diagram of an example implementation of an error detection module; FIGS. 8-10 are flowcharts illustrating an exemplary method for detecting an eccentricity error of the motor; and FIG. 11 is an exemplary graph of incremental inductance versus d-axis current for motors with different eccentricity levels.In the drawings, reference numerals may be used multiple times to identify similar and / or similar elements.DETAILED DESCRIPTIONAn inverter module of a vehicle includes branches of switches that regulate the flow of current (a) from a battery to an electric motor and (b) from the electric motor to the battery. A DC bus (DC bus) capacitor may be connected between the inverter module and the battery. Pulse width modulated (PWM) signals are used to control the switching of the branches.Electric motors may have various types of faults. One type of error is an eccentricity error. Eccentricity errors may occur due to manufacturing and / or assembly tolerances, for example. Eccentricity errors produce an unbalanced magnetic field that can cause vibrations, noise, and increased forces in one or more engine bearings, which can result in increased wear, previous perturbation, and increased losses. Over time, eccentricity may continue to increase and cause a rotor and a stator of the motor to contact.The present application includes a fault detection module that detects an eccentricity error of an electric motor based on vibration and the incremental inductance of the electric motor. According to various implementations, the detection of the eccentricity error may be further based on the voltage commands for the motor. In vehicles, this detection may be performed before a vehicle is sold. The use of the oscillation and incremental inductance (and, in addition, voltage commands in accordance with some examples) is a more robust measurement of eccentricity that limits the possibility of false detections and increases the accuracy of detecting eccentricity errors of electric motors.Referring now to FIG. 1, a functional block diagram of an example vehicle system is shown. While a vehicle system for a hybrid vehicle is shown and described, the present disclosure is also applicable to electric vehicles that do not include an internal combustion engine (including electric-only vehicles), fuel cell vehicles, autonomous vehicles, semi-autonomous vehicles, non-autonomous vehicles, and other types of vehicles. While the example of a vehicle is provided, the present application is also applicable to non-vehicle implementations.An engine 102 may combust an air / fuel mixture to generate drive torque. An engine control module (ECM) 114 controls the engine 102. For example, the ECM 114 may control actuation of engine actuators such as a throttle, one or more spark plugs, one or more fuel injectors, valve actuators, camshaft phasers, an exhaust gas recirculation (EGR) valve, one or more boost devices, and other suitable engine actuators. In some types of vehicles (e.g., electric vehicles), the engine 102 may be omitted.The engine 102 may output torque to a transmission 195. A transmission control module (TCM) 194 controls operation of the transmission 195. For example, the TCM 194 may control gear selection within the transmission 195 and one or more torque-transmitting devices (e.g., a torque converter, one or more clutches, etc.).The vehicle system includes one or more electric motors, such as electric motor 198. An electric motor may act as either a generator or a motor at a given time. When an electric motor acts as a generator, it converts mechanical energy into electrical energy. The electrical energy may be used, for example, to charge a battery 199. When an electric motor acts as a motor, it generates torque that can be used for vehicle propulsion, for example. While the example of an electric motor is provided, the vehicle may include more than one electric motor.An engine control module 196 controls power flow from the battery 199 to the electric motor 198 and from the electric motor 198 to the battery 199. The engine control module 196 applies electrical power from the battery 199 to the electric motor 198 to cause the electric motor 198 to output a positive torque, such as for vehicle propulsion. The battery 199 may include, for example, one or more batteries and / or one or more battery packs.The electric motor 198 may output torque to, e.g., an input shaft of the transmission 195 or an output shaft of the transmission 195. A clutch 200 may be engaged to couple the electric motor 198 to the transmission 195 and disengaged to decouple the electric motor 198 from the transmission 195. One or more transmission devices may be implemented between an output of clutch 200 and an input of transmission 195 to provide a predetermined relationship between the rotation of electric motor 198 and the rotation of the input of transmission 195.The engine control module 196 may also selectively convert mechanical energy of the vehicle into electrical energy. More specifically, the electric motor 198 generates and outputs power via the back EMF when the electric motor 198 is driven by the transmission 195 and the engine control module 196 is not applying power from the battery 199 to the electric motor 198. The engine control module 196 may charge the battery 199 via the power output by the electric motor 198.Referring now to FIG. 2, a functional block diagram of an exemplary drive control system is shown. A driver torque module 204 determines a driver torque request 208 based on a driver input 212. The driver input 212 may include, for example, an accelerator pedal position (APP), a brake pedal position (BPP), a cruise control input, and / or an autonomous input. According to various implementations, the cruise control input may be provided by an adaptive cruise control system that attempts to maintain at least a predetermined distance between the vehicle and objects on a path of the vehicle. The autonomous input may be provided by an autonomous driving system that controls the movement of a vehicle from location to location while avoiding objects and other vehicles. The driver torque module 204 may determine the driver torque request 208 using one or more look-up tables or equations that relate the driver inputs to driver torque requests. The APP and the BPP may be measured using one or more APP sensors and BPP sensors, respectively.The driver torque request 208 may be an axle torque request. Axle torques (including axle torque requests) refer to torque at the wheels. As discussed further below, drive torques (including drive torque requests) differ from axle torques in that drive torques may relate to torque at a transmission input shaft.An axle torque arbitration module 216 arbitrates between the driver torque request 208 and other axle torque requests 220. Axle torque (torque at the wheels) may be generated by various sources including the engine 102 and / or one or more electric motors, such as the electric motor 198. Examples of the other axle torque requests 220 include, but are not limited to, a torque reduction request requested by a traction control system when positive wheel slip is detected, a torque increase request to counteract negative wheel slip, brake management requests to reduce the axle torque to ensure that the axle torque does not exceed the ability of the brakes to hold the vehicle when the vehicle is stopped, and vehicle overdrive torque requests to reduce the axle torque to prevent the vehicle from exceeding a predetermined speed. The axle torque arbitration module 216 outputs one or more axle torque requests 224 based on the results of arbitration between the received drive and axle torque requests 208 and 220, respectively.In hybrid vehicles, a hybrid module 228 may determine how much of the one or more axle torque requests 224 should be generated by the engine 102 and how much of the one or more axle torque requests 224 should be generated by the electric motor 198. The example of the electric motor 198 continues for simplicity, but multiple electric motors may be used. The hybrid module 228 outputs one or more engine torque requests 232 to a drive torque arbitration module 236. Engine torque requests 232 indicate a requested torque output of engine 102.The hybrid module 228 also outputs an engine torque request 234 to the engine control module 196. The motor torque request 234 indicates a requested (positive or negative) torque output of the electric motor 198. For vehicles where the engine 102 is omitted (e.g., electric vehicles) or not associated with the output drive torque for the vehicle, the axle torque arbitration module 216 may issue an axle torque request, where the motor torque request 234 may be equal to that axle torque request.According to the example of an electric vehicle, the ECM 114 may be omitted and the driver torque module 204 and the axle torque arbitration module 216 may be implemented within the engine control module 196. For electric vehicles, the driver torque module 204 may input the driver torque request 208 to the motor control module 196, and the components related to controlling the engine actuators may be omitted.The drive torque arbitration module 236 converts the engine torque requests 232 from an axle torque range (torque at the wheels) to a drive torque range (e.g., torque at an input shaft of the transmission). The drive torque arbitration module 236 arbitrates the converted torque requests with other drive torque requests 240. Examples of the other drive torque requests 240 include, but are not limited to, torque reductions requested for engine overspeed protection and torque increases requested for preventing stalling. The drive torque arbitration module 236 may issue one or more drive torque requests 244 as a result of the arbitration.An actuator control module 248 controls the actuators 252 of the engine 102 based on the drive torque requests 244. For example, the actuator control module 248 may control opening of a throttle, timing of spark provided by spark plugs, timing and amount of fuel injected by fuel injectors, cylinder activation / deactivation, phasing of intake and exhaust valves, output of one or more boost devices (e.g., turbochargers, superchargers, etc.), opening of an EGR valve, and / or one or more other engine actuators based on the drive torque requests 244. According to various implementations, the drive torque requests 244 may be adjusted or modified prior to use by the actuator control module 248, such as to generate a torque reserve.The engine control module 196 controls switching of switches of an inverter module based on the engine torque request 234, as discussed further below. The inverter module converts direct current (DC) power to alternating current (AC) power. The inverter module feeds alternating current to the motor 198. The switching of the inverter module controls the torque of the electric motor 198. The inverter module also converts the power generated by the electric motor 198 to DC power and outputs the DC power to the battery 199, e.g., to charge the battery 199.The inverter module includes multiple switches, such as three switch branches. The engine control module switches the switches to feed alternating current (AC) power to the electric motor 198 and drive the electric motor 198. For example, the inverter module may generate n-phase AC power and feed the n-phase AC power into (e.g., a, b, and c or u, v, and w) n stator windings of the electric motor 198. According to various implementations, n is equal to 3. The magnetic flux generated by the current flow through the stator windings drives a rotor of the electric motor 198. The rotor is connected to an output shaft of the electric motor 198 and drives the rotation thereof. The output shaft of the electric motor 198 is connected to one or more wheels of the vehicle.According to various implementations, one or more filters (e.g., capacitors) may be electrically connected between the inverter module and the battery 199. For example, the one or more filters may be implemented to filter the power flow to and from the battery 199. As an example, a filter including one or more capacitors and resistors may be electrically connected in parallel with the battery 199 and the inverter module.FIG. 3 includes a diagram including an example implementation of a power control system. The battery 199 may also be referred to as a battery pack or may include a battery pack, as discussed above.The high (positive, DC+) and low (negative, DC) sides 304 and 308 are connected to the positive and negative terminals of the battery 199, respectively. One or more capacitors, such as capacitor 312, are connected in parallel with battery 199 between high and low sides 304 and 308. The one or more capacitors stabilize the DC bus and provide a low impedance voltage source to the inverter module because the battery 199 may have a higher impedance.An inverter module 316 includes three branches, one branch connected to each phase of the electric motor 198. The inverter module 316 controls current flow to the branches / phases of the electric motor 198. The inverter module 316 converts the DC power from the high and low sides 304 and 308 to 3-phase AC power and outputs the AC power to the electric motor 198.FIG. 4 includes a schematic of an example implementation of the inverter module 316. The inverter module 316 includes three branches. One branch is connected to each phase of the electric motor 198.A first branch 512 includes first and second switches 516 and 520. The switches 516 and 520 each include a first terminal, a second terminal, and a control terminal. Each of the switches 516 and 520 may be an insulated gate bipolar transistor (IGBT), a field effect transistor (FET) such as a metal oxide semiconductor FET (MOSFET), or another suitable type of switch. According to the example of the IGBTs and FETs, the control terminal is referred to as a gate.The first terminal of the first switch 516 is connected to the high side 304. The second terminal of the first switch 516 is connected to a node 504. The second terminal of the second switch 520 may be connected to the low side 308. The node 504 is connected to the second terminal of the first switch 516, the first terminal of the second switch 520, and a first phase (e.g., c) of the electric motor 198.The first branch 512 may include first and second diodes 524 and 528 that are connected in antiparallel with the switches 516 and 520, respectively. In other words, an anode of the first diode 524 may be connected to the second terminal of the first switch 516, while a cathode of the first diode 524 may be connected to the first terminal of the first switch 516. An anode of the second diode 528 may be connected to the second terminal of the second switch 520, while a cathode of the second diode 528 may be connected to the first terminal of the second switch 520. Diodes 524 and 528 form a phase of a three phase rectifier for converting the power from electric motor 198 into power for battery 199. However, diodes 524 and 528 may be omitted, such as if switches 516, 540, 556, 520, 544, and 560 are MOSFETs (with a built-in diode). The diodes 524 and 528 may be included if included in a power module of an IGBT.The inverter module 316 also includes the second and third branches 532 and 536. The second and third branches 532 and 536 may be similar or identical (in circuit arrangement) to the first branch 512. In other words, the second and third branches 532 and 536 may include respective switches and diodes, such as switches 516 and 520 and diodes 524 and 528, connected in the same manner as the first branch 512. The second branch 532 includes, for example, switches 540 and 544 and anti-parallel diodes 548 and 552. A node 542 is connected to the first terminal of the switch 544 and a second stator winding (e.g., b) of the electric motor 198. Third branch 536 includes switches 556 and 560 and anti-parallel diodes 564 and 568. A node 570 is connected to the first terminal of the switch 560 and a third stator winding (e.g., a) of the electric motor 198. Like diodes 524 and 528, diodes 548, 552, 564 and 568 may be omitted.The control terminals of the switches of the inverter module 316 are connected to the switching signals 576 from the engine control module 196. The engine control module 196 generates the switching signals 576 such that the high side switch of a branch is turned on, while the low side switch of that branch is turned off, and vice versa. The engine control module 196 generates the switching signals 576 using pulse width modulation (PWM) control.The control signals of the gates of the low side switches 520, 544, and 560 may be inverted such that the control signals applied to the low side switches 520, 544, and 560 are of an opposite polarity to the control signals applied to the gates of the high side switches 516, 540, and 556.FIG. 5 is a functional block diagram of an example implementation of the motor control module 196. A switching module 604 controls switching of switches 516 and 520 using the pulse width modulation (PWM) signals. For example, the switching module 604 applies the PWM signals to the control terminals of the switches 516, 520, 540, 544, 556, and 560. When a high side switch is turned on, power flows from the battery 199 to the electric motor 198 to drive the electric motor 198.The states of the high and low side switches of each phase are complementary (opposite) in view of the inversion of the signals applied to the gates of the low side switches 520, 544 and 560. For example, the low side switch 520 of the first branch 512 is off when the high side switch 516 of the first branch 512 is on and vice versa. The low side switch 544 of the second branch 532 is turned off when the high side switch 540 of the second branch 532 is turned on and vice versa. The low side switch 560 of the third branch 536 is turned off when the high side switch 556 of the third branch 536 is turned on and vice versa.The PWM signals provided to the second and third branches 532 and 536 may be out of phase with each other and from the PWM signals provided to the switches 516 and 520 of the first branch 512. The PWM signals for each branch may be phase shifted from every other branch by 120° (360° / 3 branches=120° shift per branch), for example. In this manner, the currents through the stator windings (phases) of the electric motor 198 may be 120° out of phase with each other. Various types of PWM schemes for three-phase voltage source inverters, such as space vector modulation, sine-triangle modulation, third harmonic injection modulation, discontinuous modulation, or another suitable PWM scheme, may be used.A current command module 608 determines a d-axis current command (Id command) and a q-axis current command (Iq command) for the electric motor 198 based on the motor torque request 234, a (mechanical) rotor speed 632 of the electric motor 198, and a DC bus voltage 610. The current command module 608 can determine the d- and q-axis current commands using one or more equations and / or look-up tables that relate the motor torque requests, rotor speeds, and DC bus voltages to the d- and q-axis current commands.The d-axis current command and the q-axis current command are collectively illustrated by 612 in FIG. 5. A voltage sensor 611 measures the DC bus voltage 610 between the battery 199 and the inverter module 316 (e.g., between the high and low sides 304 and 308), such as a voltage across a DC bus capacitor. The axis of the magnetic field or rotor winding field is referred to as the rotor longitudinal axis or d-axis.The axis that is 90 degrees after the d-axis is referred to as the quadrature axis or q-axis.The rotor rotational speed 632 is a (mechanical) rotational speed of the rotor of the electric motor 198. The rotor speed 632 may be measured using, for example, a rotor speed sensor 636. According to various implementations, the rotor speed 632 may be determined by a rotor speed module based on one or more other parameters, such as a change in position of the rotor over time, the position determined based on the currents 640 of the electric motor 198. According to various implementations, the rotor speed sensor 636 may determine a position of the rotor, wherein the rotor speed sensor 636 (or a speed module such as the motor control module 196) may determine the rotor speed 632 based on a change in rotor position over time (e.g., using a mathematical derivative of position with respect to time). Current sensors 642 may measure phase currents 640 (e.g., la, Ib, Ic) as in the respective branches of inverter module 316. According to various implementations, one or more of the phase currents 640 may be estimated.A voltage command module 656 (which may be referred to as a current regulator) determines the voltage commands for the electric motor 198 based on the d-axis current command, the q-axis current command, a d-axis current of the electric motor 198, and a q-axis current of the electric motor 198. The d-axis voltage command and the q-axis voltage command are collectively illustrated by 660 in FIG. 5. According to various implementations, the voltage command module 656 may generate the voltage commands 660 using a feedback control based on the d- and q-axis currents 644 or generate the voltage commands 660 using a feedback control to adjust the d- and q-axis currents 644 towards or towards the d- and q-axis current commands 612. A reference system (FOR) module 648 may transform the phase currents 640 into the d- and q-axis currents 644 by applying a Clarke transformation and a Park transformation.The switching module 604 determines duty cycles of the PWM signals applied to the switches of the inverter module 316 to generate the voltage for the electric motor 198 based on the d- and q-axis voltage commands, respectively. For example, the switching module 604 may determine the PWM duty cycle using one or more schemes (e.g., algorithms) that use equations or look-up tables that relate the voltage commands to the PWM duty cycles. Exemplary PWM schemes for three-phase voltage source inverters include, but are not limited to, space vector modulation, sine-triangle modulation, third harmonic injection modulation, and discontinuous modulation.The switching module 604 switches the switches of the inverter module 316 based on the PWM duty cycles for the phases and a target switching frequency 670. The duty cycle of a phase corresponds to the period in which the high-side switch of the phase is turned on (closed) during the period corresponding to the target switching frequency 670 (period=1 / target switching frequency). The PWM schemes may have a fixed switching frequency with a modulated duty cycle.A target frequency module 674 determines the target switching frequency 670. The target frequency module 674 may set the target switching frequency 670 for each phase. More specifically, the target frequency module 674 sets the target switching frequency for the first phase, the target switching frequency for the second phase, and the target switching frequency for the third phase of the inverter module 316. The target switching frequency for each phase may be the same. The switching module 604 switches the switches of the phases of the inverter module 316 based on the PWM duty cycles and the target switching frequencies of the phases, respectively.FIG. 6 is a functional block diagram of an error detection system. A fault detection module 680 detects the presence of an eccentricity error in the electric motor 198 based on a vibration 682 of the motor 198 measured using a vibration sensor 684 and an incremental inductance of the motor determined based on the d- and q-axis currents 644. The error detection module 680 may further detect the presence of the eccentricity error based on the voltage commands 660.The output shaft 686 of the motor 198 may be connected to a dynamometer 688 for detecting whether the motor 198 has an eccentricity error. According to various implementations, the dynamometer 688 may be omitted. If the dynamometer 388 is omitted, the eccentricity errors may be detected based on the incremental inductance and the vibration-based analysis. If the motor 198 includes an eccentricity error, the error detection module 680 may visually indicate that the motor 198 has an eccentricity error, such as by illuminating a display 690. The fault detection module 680 may additionally or alternatively perform one or more other remedial actions when the engine 198 has an eccentricity error, such as deactivating the engine 198 via the engine control module 196. The eccentricity of the motor 198 may refer to the extent to which the center of the stator is aligned with the center of the rotor and the axis of the output shaft 686.The eccentricity of the motor 198 may be expressed as a value between 0 and 100, or in another suitable manner. According to the example of the values between 0 and 100, 0 may indicate that the center of the stator is aligned with both the center of the rotor and the axis of the output shaft (the line through the axis of the output shaft would extend through both the center of the rotor and the center of the stator). 100 may indicate that the center of the stator is misaligned from the center of the rotor and the axis of the output shaft by at least a predetermined distance (e.g., radial distance). While this example is described herein, the present application is also applicable to other forms of eccentricity term.FIG. 7 is a functional block diagram of an example implementation of the error detection module 680. A vibration eccentricity module 704 determines a vibration eccentricity 708 of the motor 198 based on vibration 682 of the motor 198 by the vibration sensor 684. The vibration eccentricity module 704 may determine the vibration eccentricity 708 using a look-up table or equation that relates one or more characteristics of the vibration 682 to the vibration eccentricity. As discussed above, according to one example, the oscillation eccentricity 708 may be expressed as a value between 0 and 100. The engine control module 196 operates the engine 198 under predetermined operating conditions to determine the oscillation eccentricity 708.A voltage eccentricity module 712 determines a voltage eccentricity 716 of the motor 198 based on one or more of the voltage commands 660 for the motor 198. The voltage eccentricity module 712 may determine the voltage eccentricity 716 using a look-up table or equation that relates one or more of the voltage commands 660 to the voltage eccentricity. As discussed above, according to one example, the stress eccentricity 716 may be expressed as a value between 0 and 100. The engine control module 196 operates the engine 198 under predetermined operating conditions to determine the voltage eccentricity 716.An inductance eccentricity module 720 determines an inductance eccentricity 724 of the motor 198 based on one or more points on an incremental inductance (profile) curve 728 for the motor 198. The inductance eccentricity module 720 may determine the inductance eccentricity 724 using a look-up table or equation that relates one or more characteristics of the incremental inductance curve 728 to the inductance eccentricity. As discussed above, according to one example, the inductance eccentricity 724 may be expressed as a value between 0 and 100. The engine control module 196 operates the engine 198 under predetermined operating conditions to determine the incremental inductance curve 728.An incremental inductance module 732 determines the incremental inductance curve 728 based on, e.g., one or more of the d- and q-axis currents 644 of the motor 198.An error module 736 determines whether the motor 198 has an eccentricity error based on the oscillation eccentricity 708 and the inductance eccentricity 724, as will be discussed further below. The error module 736 may additionally determine whether the motor 198 has an eccentricity error based on the voltage eccentricity 716, as will be discussed further below.If the motor 198 has an eccentricity error, the error module 736 may take one or more actions. For example, the fault module 736 may visually output an indication that the motor 198 has an eccentricity fault, such as by turning on the display 690. Additionally or alternatively, the fault module 736 may command the engine control module 196 to deactivate the electric motor 198 and / or limit the torque output of the engine 198 to a predetermined fault torque.FIGS. 8-10 are flowcharts illustrating an exemplary method for detecting an eccentricity error of the motor 198. FIG. 8 is a flow chart illustrating an example method for determining the oscillation eccentricity. FIG. 9 is a flow chart illustrating example methods for determining inductance and voltage eccentricity. FIG. 10 is a flow chart illustrating an example method for determining whether the motor 198 has an eccentricity error. Figures 8-10 may be performed in a predetermined order.In FIG. 8, control begins at 804, where the engine control module 196 selects one or more operating parameters of the engine 198 to detect eccentricity based on vibration. The one or more operating parameters may include, for example, a predetermined speed of the engine 198 that is greater than zero, such as 1000 revolutions per minute, or another suitable speed.At 808, the engine control module 196 controls the engine 198 with the one or more selected operating parameters (e.g., the predetermined speed). At 812, the vibration sensor 684 measures the vibration of the motor 198 during operation of the motor 198 at the one or more selected operating parameters.At 816, the vibration eccentricity module 704 determines the vibration amplitudes or predetermined frequencies, such as by applying a fast Fourier transform (FFT) to the vibration signal from the vibration sensor 684. At 820, the vibration eccentricity module 704 determines the vibration eccentricity 708 based on one or more of the amplitudes of the vibration at each of one or more of the frequencies. For example, the vibration eccentricity module 704 may determine the vibration eccentricity 708 using one or more equations and / or lookup tables that relate the one or more amplitudes to the vibration eccentrics.At 824, the error module 736 may determine whether the vibration eccentricity is greater than a predetermined value. The predetermined value may be, for example, 0.75 (75%) using the above example range of values or another suitable value. If 824 is true, the error module 736 may indicate that the motor 198 has an eccentricity error at 832, and control may continue at 836. At 836, the vibration eccentricity module 704 may determine an amplitude of the acceleration of the vibration of the motor 198 at one of the frequencies. If 824 is false, the error module 736 may indicate that the motor 198 does not have an eccentricity error at 828.Control may continue to I (FIG. 9 ) after 828 or 836.In FIG. 9, control may begin at 904 where the engine control module 196 selects one or more operating parameters of the engine 198 to detect eccentricity based on the voltage commands. The one or more operating parameters may include, for example, a predetermined speed of the engine 198 that is greater than zero, such as 1000 revolutions per minute, or another suitable speed, and a predetermined torque that is greater than zero, such as 50 Newton-meters, or another suitable torque, 0 or a predetermined negative torque. At 908, the engine control module 196 operates the engine 198 at the one or more selected operating parameters.At 912, the voltage eccentricity module 712 receives the voltage commands 660 used to operate the motor at the selected operating parameters (e.g., the predetermined speed and torque). At 916, the voltage eccentricity module 712 determines the voltage eccentricity 716 based on the voltage commands 660. For example, the voltage eccentricity module 712 may determine the voltage eccentricity 716 using one or more equations and / or lookup tables that relate the one or more amplitudes to the voltage eccentrics.At 920, the error module 736 may determine whether the voltage eccentricity 716 is greater than a predetermined value. The predetermined value may be, for example, 0.75 (75%) using the above example range of values or another suitable value. If 920 is false, the error module 736 may indicate that a first eccentricity (A) for the motor 198 is error free (no eccentricity error) at 924, and control may continue at II (FIG. 10 ). If 920 is true, the error module 736 may indicate that the first eccentricity (A) for the motor 198 has an eccentricity at 928, and control may continue at II.932-960 The processing may be performed after or before 904-928. At 932, where the engine control module 196 selects one or more operating parameters of the engine 198 to detect eccentricity based on the incremental inductance of the engine 198. For example, the one or more operating parameters may include a predetermined maximum d-axis current to saturate the motor 198. According to various implementations, the one or more operating parameters include a predetermined range of d-axis current. At 936, the engine control module 196 operates the engine 198 with the one or more selected operating parameters.At 940, the incremental inductance module 732 determines the incremental inductance curve 728 for the motor 198 during operation of the motor 198 at the selected operating parameters, such as based on the d-axis current of the motor 198. FIG. 11 includes an example graph of incremental inductance 1104 versus d-axis current 1108. Curves 1112, 1116, and 1120 are for decreasing (better) engine eccentricity.At 944, the inductance eccentricity module 720 determines the d-axis current (e.g., 1108) at the second peak (bump) in the incremental inductance curve 728 and the incremental inductance (e.g., 1104), which may also be referred to as a magnitude, at this d-axis current. For example, the inductance eccentricity module 720 may determine the height of the peak from the piecewise linear trend of the curve to determine the eccentricity. There is a difference between an absolute peak and a peak of the curve from the piecewise linear trend of the curve. At 948, the inductance eccentricity module 720 determines the inductance eccentricity 724 based on the d-axis current and the incremental inductance determined at 944. For example, the inductance eccentricity module 720 may determine the inductance eccentricity 724 using one or more equations and / or lookup tables that relate d-axis currents and the incremental inductances to the inductance eccentricities.At 952, the error module 736 may determine whether the inductance eccentricity 724 is greater than a predetermined value. The predetermined value may be, for example, 0.75 (75%) using the above example range of values or another suitable value. If 952 is false, the error module 736 may indicate that a second eccentricity (B) for the motor 198 is error free (no eccentricity error) at 956, and control may continue at II (FIG. 10 ). If 952 is true, the error module 736 may indicate that the second eccentricity (B) for the motor 198 has an eccentricity at 960, and control may continue at II.In FIG. 10, at 1004, the fault module 736 determines whether the first and second eccentricity (A and B) both indicate that the motor 198 is fault-free. If 1004 is true, the error module 736 may output an indication that the motor 198 does not have an eccentricity error at 1008, and control may end. If 1004 is false, control may be transferred to 1012.At 1012, the error module 736 may determine whether the first eccentricity (A) does not indicate eccentricity (error free) and the inductance eccentricity value 724 is less than a second predetermined value. The second predetermined value may be less than or equal to the predetermined value compared to the inductance eccentricity value 724 at 952. If 1012 is true, control may continue at 1020. If 1012 is false, control may continue at 1016.At 1016, the error module 736 may determine whether the second eccentricity (B) does not indicate eccentricity (error free) and the voltage eccentricity value 716 is less than a second predetermined value. The second predetermined value may be less than or equal to the predetermined value compared to the voltage eccentricity value 716 at 920. If 1016 is true, control may continue at 1020. If 1016 is false, control may continue at 1024.At 1020, the error module 736 may determine whether the amplitude of the oscillation (from 836) is less than a predetermined value. If 1020 is true, control continues at 1008 where the error module 736 indicates that the motor 198 does not have an eccentricity error. If 1020 is false, control continues at 1028. At 1028, the error module 736 may output an indication that the motor 198 has an eccentricity error at 1008. One or more other remedial actions may be taken. For example, the fault module 736 may deactivate the engine 198 or limit the torque output of the engine 198. The engine 198 may be replaced with a non-defective engine before the vehicle exits the manufacturing process. At 1024, the error module 736 may determine whether both the value of the oscillation eccentricity 716 and the inductance eccentricity value 724 are greater than the second predetermined value. If 1024 is true, control continues at 1028. If 1024 is false, control may proceed to 1020.The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure may be implemented in various forms. Therefore, while this disclosure includes specific examples, the true scope of the disclosure should not be so limited because other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be appreciated that one or more steps within a method may be performed in different order (or simultaneously) without altering the principles of the present disclosure. Further, although each of the embodiments has been described above with certain features, one or more of these features described with respect to any embodiment of the disclosure may be implemented in any of the other embodiments and / or combined with the features of any of the other embodiments, even if this combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, permutations of one or more embodiments with each other remaining within the scope of this disclosure.Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms including "connected," "engaged," "coupled," "adjacent," "next to," "top on," "over," "under," and "disposed.".When a relationship between first and second elements is described in the above disclosure, this relationship may be a direct relationship in which no other intervening elements are present between the first and second elements, but may also be an indirect relationship in which one or more intervening elements (either spatially or functionally) are present between the first and second elements unless expressly described as "direct". As used herein, the term at least one of A, B, and C should be construed to mean a logical (A OR B OR C) using a non-exclusive logical OR, and should not be construed to mean "at least one of A, at least one of B, and at least one of C.".In the figures, the direction of an arrow, as indicated by the arrow head, generally demonstrates the flow of information (such as data or instructions) of interest for the illustration. For example, if element A and element B exchange different information, but the information transmitted from element A to element B is relevant for illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, the element B for the information transmitted from the element A to the element B may transmit requests for or reception acknowledgments of the information to the element A.In this application, including the definitions below, the term "module" or the term "controller" may be replaced by the term "circuit". The term "module" may refer to, be part of, or include: an application specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores the code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system on a chip.The module may include one or more interface circuits. According to some examples, the interface circuits may include wired or wireless interfaces connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed between multiple modules connected via interface circuits. For example, multiple modules may allow load balancing. According to another example, a server module (also known as a remote or cloud module) may perform some functionality on behalf of a client module.The term code as used above may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects. The term shared processor circuit includes a single processor circuit that executes some or all of the code from multiple modules. The term group processor circuit includes processor circuit that, in combination with additional processor circuits, executes some or all of the code from one or more modules. References to multiple processor circuits include multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit includes a single memory circuit that stores some or all of the code from multiple modules. The term group memory circuit includes a memory circuit that, in combination with additional memories, stores some or all of the code from one or more modules.The term memory circuitry is a subset of the term computer readable medium. The term computer-readable medium as used herein does not include transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (e.g., a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray disc).The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer generated by configuring a general purpose computer to perform one or more special purpose functions embodied in computer programs. The above-described function blocks, flowchart components, and other elements serve as software specifications that can be translated into computer programs by the routine work of a skilled technician or programmer.The computer programs include processor-executable instructions stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also contain stored data or rely on stored data. The computer programs may include a basic input / output system (BIOS) interacting with the hardware of the special purpose computer, device drivers interacting with specific devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.The computer programs may include: (i) descriptive text to be parse, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript object designation), (ii) assembler code, (iii) object code generated by a compiler from source code, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. Merely as examples, the source code may be generated using the syntax of languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java® Fortran, Perl, Pascal, Curl, OCaml, Javascript® HTML5 (hypertext markup language, 5th revision), Ada, ASP (active server pages), PHP (PHP: hypertext preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash® Visual Basic® Lua, MATLAB, SIMULINK, and Python® may be written.LegendIn the drawing figures, N represents No and Y represents Yes.

Claims

An eccentricity detection system comprising: a vibration eccentricity module (704) configured to determine a vibration eccentricity (708) of one of the electric motor (198) based on a vibration (682) of the electric motor (198) measured during operation of the electric motor (198); an inductance eccentricity module (720) configured to determine an inductance eccentricity (724) of the electric motor (198) based on a curve of the incremental inductance (728) of the electric motor (198); and an error module (736) configured to indicate whether the electric motor (198) includes an eccentricity error based on both a) of the vibration eccentricity (708) of the electric motor (198) and b) of the inductance eccentricity (724) of the electric motor (198).The eccentricity detection system of claim 1, wherein the error module (736) is configured to selectively indicate that the electric motor (198) has an eccentricity error when the vibration eccentricity (708) is greater than a predetermined value.The eccentricity detection system of claim 1, wherein the error module (736) is configured to selectively indicate that the electric motor (198) has an eccentricity error when the inductance eccentricity (724) is greater than a predetermined value.The eccentricity detection system of claim 1, further comprising a voltage eccentricity module (712) configured to determine a voltage eccentricity (716) of the electric motor (198) based on a voltage command (660) for the electric motor (198), wherein the error module (736) is configured to further indicate whether the electric motor (198) includes an eccentricity error based on the voltage eccentricity (716).The eccentricity detection system of claim 4, wherein the error module (736) is configured to selectively indicate that the electric motor (198) has an eccentricity error when the voltage eccentricity (716) is greater than a predetermined value.The eccentricity detection system of claim 4, wherein the stress command (660) is a d-axis stress command.The eccentricity detection system of claim 4, wherein the stress command (660) is a q-axis stress command.The eccentricity detection system of claim 4, wherein the voltage eccentricity module (712) is configured to determine the voltage eccentricity (716) of the electric motor (198) when the electric motor (198) is operating at a predetermined speed.The eccentricity detection system of claim 4, wherein the voltage eccentricity module (712) is configured to determine the voltage eccentricity (716) of the electric motor (198) when the electric motor (198) is operating at a predetermined torque.The eccentricity detection system of claim 1, wherein the vibration eccentricity module (704) is configured to determine the vibration eccentricity (708) of the electric motor (198) when the electric motor (198) is operating at a predetermined speed.

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