Abstract: A method for monitoring an electric motor employing a pulse-type rotational position sensor includes monitoring a signal output from the pulse-type rotational position sensor and a reference signal associated with a control signal for the electric motor. A position of a rotor of the electric motor coincident with the reference signal is determined based upon a nominal rotor position, a nominal rotational speed of the rotor and a time between the reference signal and a falling edge of the signal output from the pulse-type rotational position sensor. The electric motor is controlled based upon the position of the rotor.

Abstract: A vehicle includes a motor having a rotor shaft, a transmission having a gear set directly or selectively connected to the motor, a resolver circuit, and a controller. The resolver circuit includes a resolver that measures an absolute position of the shaft, and a resolver-to-digital converter (RDC) which receives the absolute position and generates, via a tracking loop, a raw position signal. The controller includes recorded predetermined frequency characteristics of the RDC and method instructions which cause the controller to receive the raw position signal from the RDC and create a lookup table describing position wobble. The controller compensates for the position wobble at all rotational speeds of the rotor shaft by applying the predetermined frequency characteristics to the position wobble to derive a compensated position signal. The controller also uses the compensated position signal to control an operation of the electric motor.

Abstract: A method of implementing a remedial short in a rotating polyphase electric machine (EM) includes detecting a fault condition; and initially commanding a power inverter module (PIM) into an electrically-open state. Once in an open state, a controller may determine a phase angle of a current generated by the rotating EM, and may control the PIM to apply a voltage to the EM that is out-of-phase from the determined phase angle of the generated current. The magnitude of the applied voltage signal may ramped from a first voltage to zero over a period of time; whereafter the PIM may be commanded to electrically couple all of the electrical windings of the EM to each other.

Abstract: A method of increasing a current sensing range for a vehicle or other polyphase motor system includes measuring phase currents delivered to a motor of the system. A controller calculates an absolute value of each phase current, compares each calculated absolute value to a saturation limit to determine whether only one sensor is saturated, and extrapolates a phase current value of the saturated sensor. The calculated temporary phase current is used as the extrapolated phase current value for the saturated sensor, and a control action is executed using the extrapolated phase current value only when the calculated temporary phase current value exceeds the measured value for the saturated sensor and a sign of the calculated temporary phase current value matches that of the measured value for the saturated sensor. A system includes the motor, a power inverter module, phase current sensors, and a controller which executes the method.

Abstract: A method of increasing a current sensing range for a vehicle or other polyphase motor system includes measuring phase currents delivered to a motor of the system. A controller calculates an absolute value of each phase current, compares each calculated absolute value to a saturation limit to determine whether only one sensor is saturated, and extrapolates a phase current value of the saturated sensor. The calculated temporary phase current is used as the extrapolated phase current value for the saturated sensor, and a control action is executed using the extrapolated phase current value only when the calculated temporary phase current value exceeds the measured value for the saturated sensor and a sign of the calculated temporary phase current value matches that of the measured value for the saturated sensor. A system includes the motor, a power inverter module, phase current sensors, and a controller which executes the method.

Abstract: Methods, systems and apparatus are provided for generating voltage commands used to control operation of a permanent magnet machine. For example, a control system is provided that generates voltage command signals for controlling a permanent magnet machine during a transition from an initial operating condition to a final operating condition. The control system includes a processor configured to execute software instructions, and a memory configured to store software instructions accessible by the processor. The software instructions comprise a voltage command generator module. Based on an electrical angular frequency of the permanent magnet machine, and synchronous reference frame current signals, the voltage command generator module is configured to generate ramped voltage command signals that each change linearly in accordance with a slope during a transition period that is set to a rise time.

Abstract: A method includes detecting a first event and executing a first procedure to identify a sensor offset in response to detecting the first event. The method further includes determining, via a computing device, whether the sensor offset was measured during the execution of the first procedure, scheduling a second procedure to execute in response to detecting a second event if the sensor offset was not measured during the first procedure, and scheduling the first procedure to execute in response to detecting a subsequent occurrence of the first event if the sensor offset was measured during the first procedure.

Abstract: A method for monitoring an electric motor employing a pulse-type rotational position sensor includes monitoring a signal output from the pulse-type rotational position sensor and a reference signal associated with a control signal for the electric motor. A position of a rotor of the electric motor coincident with the reference signal is determined based upon a nominal rotor position, a nominal rotational speed of the rotor and a time between the reference signal and a falling edge of the signal output from the pulse-type rotational position sensor. The electric motor is controlled based upon the position of the rotor.

Abstract: A controller-implemented method for monitoring a permanent magnet electric machine includes determining a threshold direct-axis (d-axis) current corresponding to inception of irreversible demagnetization of the permanent magnet based upon material properties of a permanent magnet mounted in a rotor of the PM electric machine and a temperature of the permanent magnet. A d-axis current associated with controlling the PM electric machine is determined, and a state of health of the PM electric machine is determined based upon the threshold d-axis current and the monitored d-axis current.

Abstract: A method of implementing a remedial short in a rotating polyphase electric machine (EM) includes detecting a fault condition; and initially commanding a power inverter module (PIM) into an electrically-open state. Once in an open state, a controller may determine a phase angle of a current generated by the rotating EM, and may control the PIM to apply a voltage to the EM that is out-of-phase from the determined phase angle of the generated current. The magnitude of the applied voltage signal may ramped from a first voltage to zero over a period of time; whereafter the PIM may be commanded to electrically couple all of the electrical windings of the EM to each other.

Abstract: An electric machine electrically connects to an inverter via a multi-phase power circuit. A method for monitoring the multi-phase power circuit includes non-intrusively adjusting a commanded AC electric current from the inverter after a prescribed time period and comparing a measured magnitude of AC electric current in the multi-phase power circuit with a minimum threshold. Presence of an open circuit fault in the multi-phase power circuit can be detected based upon the comparison.

Abstract: Methods and apparatus are provided for detecting a phase current sensor fault in a multi-phase electrical motor. The method comprises, receiving an input torque command T* and measuring a set of feedback signals of the motor including a phase current Ix for each of the phases of the motor, generating direct and quadrature command phase currents Id*, Iq* for the motor corresponding to a value of the input torque command T*, determining a total command current Is=[(Iq*)2+(Id*)2]½, generating a negative sequence current Ineg, where for three phases Ineg=(?)[Ia+(?2)Ib+(?)Ic], where ?=ej2?/3, combining Ineg and Is to provide a normalized negative sequence current Inn=Ineg/Is, comparing the normalized negative sequence current Inn to a predetermined threshold value INN* to determine the presence of a phase current sensor fault, and executing a control action when Inn>INN*.

Abstract: A method of controlling a power inverter coupled to an electric motor in a vehicle powertrain having an engine is provided. The method includes generating a voltage waveform signal and a switching frequency signal for the inverter via a controller. At least one of the voltage waveform signal and the switching frequency signal is at least partially based on at least one commanded engine operating parameter. For example, the engine on/off state, engine torque, and engine speed can be considered. A vehicle having a controller configured to implement the method is also provided.

Abstract: A method of distributing processor loading in a real-time operating system between a high frequency processing task and a lower frequency processing task, the method including: making a processing request to the high frequency processing task from the lower frequency processing task, the processing request including a plurality of discrete processing commands; queuing the plurality of discrete processing commands; and executing a subset of the queued processing commands with the execution of each of a plurality of high frequency processing tasks such that the execution of the plurality of discrete processing commands is distributed across the plurality of high frequency processing tasks.

Abstract: Methods and systems are provided for determining a temperature of a motor of a vehicle having an ignition when the ignition is turned on following a period of time in which the ignition had been turned off. An amount of time for which the vehicle had been turned off is determined. A motor temperature model is run using a time step to simulate the amount of time for which the vehicle had been turned off to determine an initial value of the temperature of the motor.

Abstract: Methods, system and apparatus are provided for reducing power loss in an electric motor drive system that includes an electric machine and an inverter module. A controller determines whether a torque command (Tcmd) is less than a minimum torque threshold (Tmin) that is required to disable the inverter module, and if so, increments a counter and determines whether the torque command (Tcmd) remains less than the minimum torque threshold (Tmin). When the torque command (Tcmd) remains less than the minimum torque threshold (Tmin), the controller checks to determine whether a current count value (n) maintained at the counter is greater than a count threshold (nth), and if so, the controller can generate a disable signal to disable switching within the inverter module.

Abstract: Methods and systems are provided for assessing a vehicle transmission having a resolver. A memory is configured to store preliminary data pertaining to an error of the resolver. A processor is coupled to the memory, and is configured to determine a harmonic characteristic of the preliminary data, and to assess the vehicle transmission using the harmonic characteristic.

Abstract: A vehicle includes a polyphase, permanent magnet synchronous electric machine, DC and AC buses, a battery module, a traction power inverter module (TPIM), and a controller. The controller, which is in communication with the TPIM, executes a method to detect a fault condition, fixes the pulse width modulation (PWM) duty cycles of all phases of the electric machine to 50% such that all phases switch simultaneously, and applies a polyphase OPEN state to the AC bus in response to the detected fault condition. The controller then transitions to a polyphase SHORT state by automatically inserting an adjustable deadtime at each PWM switching transition of the TPIM over a calculated ramp duration, thereby transitioning from an initial deadtime to a minimum deadtime over the calculated ramp duration. The transition reduces peak overshoot of the negative d-axis current of the machine during the fault condition.

Abstract: Embodiments of the present disclosure relate to methods, systems and apparatus for implementing dithering in motor drive system for controlling operation of a multi-phase electric machine.

Abstract: A method for operating an electric motor is provided. The method includes receiving a torque request; determining long term torque capabilities and short term torque capabilities of the electric motor; generating a torque command based on the torque request and at least one of the long term torque capabilities or the short term torque capabilities; and controlling the electric motor in accordance with the torque command.