A method of controlling an electric motor includes receiving a duty cycle for the electric motor for delivering a target torque from the electric motor, generating a pulse train, and pulsing the electric motor with the generated pulse train. Generating the pulse train being at least partially based on the received duty cycle. The generated pulse train optimized to improve at least one of noise, vibration, or harshness of the electric motor when compared to a constant pulse frequency.

A torque security 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 the signal from the sensor that indicates 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 an inertia of the electric motor and a gearbox. The powertrain of the vehicle comprises 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.

An inverter for driving a motor that has a switchable connection of windings and drives a load element having a periodically varying load torque is provided. The inverter is controlled so that an output torque of the motor follows the periodic variation of the load torque. The inverter is controlled so that a current flowing through the motor is zero during a period including a minimum torque phase at which the load torque is at or near a minimum value. The connection is switched while the current flowing through the motor is zero. It is possible to switch the connection of the windings while the motor is rotating, and avoid an increase in apparatus size.

A method of controlling operation of an electric machine includes: determining a voltage-based torque limit based on a voltage constraint of a direct current (DC) bus supplying power to an inverter for powering the electric machine; determining a motor current-based torque limit based on a motor current limit; determining a final torque limit based on the voltage-based torque limit and the motor current-based torque limit; determining a limited command torque based on a torque command and the final torque limit; determining an initial current command corresponding to the inverter satisfying a regenerative current limit of the DC bus; and calculating a final current command based on, at least, the limited command torque and the initial current command. The method includes the final current command exceeding the initial current command to cause the electric machine to produce a torque corresponding to the limited torque command.

For high frequency injection (HFI) transition disturbance elimination, a processor directs an HFI transition for a motor. The processor determines compensation pulse voltages for an HFI compensation pulse. The processor further injects a sum of the HFI compensation pulse and an HFI voltage into a current regulator voltage output signal for a compensation Pulse Width Modulation (PWM) cycle. The HFI compensation pulse settles an HFI current to a steady state

For high frequency injection (HFI) transition disturbance elimination, a processor directs an HFI transition for a motor. The processor determines compensation pulse voltages for an HFI compensation pulse. The processor further injects a sum of the HFI compensation pulse and an HFI voltage into a current regulator voltage output signal for a compensation Pulse Width Modulation (PWM) cycle. The HFI compensation pulse settles an HFI current to a steady state.

Methods, apparatus, systems and articles of manufacture are disclosed to improve electronic power assisted steering in a vehicle. An example apparatus includes memory and a processor to execute instructions to determine a steering column torque associated with a steering column of an electronic power assisted steering (EPAS) system in a vehicle, determine a steering column torque derivative based on a derivative of the steering column torque, determine a compliance compensation torque based on the steering column torque and the steering column torque derivative, and adjust a steering response of the steering column based on the compliance compensation torque.

A first torque calculation unit 114 calculates torque TQ_DC currently generated by a motor 106 based on a DC current DC1. A second torque calculation unit 115 calculates torque TQ_UVW currently generated by the motor 106 based on U-phase, V-phase, and W-phase currents. A torque limit calculation unit 116 calculates a torque limit TQ_LMT1 using a torque limit characteristic map measured in advance based on a current limit DC_LMT1. A torque limit correction unit 117 compares first torque TQ_DC with second torque TQ_UVW to calculate a torque variation degree KP1. Then, the torque limit TQ_LMT1 is corrected using the variation degree KP1 to calculate a torque limit TQ_LMT2. As a result, even if required torque reaches the torque limit, the DC current does not exceed the current limit, and the output of the motor can be fully utilized by approaching the current limit.

A drive system includes: a drive device including an electric motor; and a torque controller that controls operations of the electric motor to control torque output from the electric motor. The torque controller includes a target-motor-torque determiner that determines target motor torque based on a sum of motor requested torque and a value obtained by multiplying a gain by sprung-portion-vibration-control torque. The target motor torque is a target value of the torque output from the electric motor. The motor requested torque is determined based on vehicle requested torque requested for driving of the vehicle. The torque controller includes a gain determiner that determines the gain to a value that is less when an absolute value of the motor requested torque is small with respect to the sprung-portion-vibration-control torque than when the absolute value is large with respect to the sprung-portion-vibration-control torque.

The invention related to a control method for operating a synchronous machine, the machine comprising an exciter connected to a synchronous generator and a controller (40) for controlling the machine field excitation. The method comprises the steps of predefining a stable operation torque derivative range within which a stable operation of the machine occurs, performing a torque measuring or calculating for the machine, calculating the derivative of said torque, determining whether the calculated torque derivative is within the predefined stable operation torque derivative range for the machine, and, if the torque derivative is not within the predefined stable operation torque derivative range, modifying the machine field excitation to bring the torque derivative within the predefined stable operation torque derivative range.