Abstract: Technical solutions are described for estimating machine parameters of a permanent magnet synchronous motor (PMSM) drive. An example method includes determining a region for estimating a machine parameter based on a motor velocity value and a motor current value. The method further includes, in response to the motor velocity value and the motor current value being in the region, estimating an error in estimated voltage command, and estimating the machine parameter using the error in estimated voltage command.

Abstract: Systems and methods for compensating for a current measurement offset error in a permanent magnet synchronous motor (PMSM) drive are disclosed. The systems and methods include reading an output voltage command signal, extracting a signature of a current measurement offset error from the output voltage command signal, and compensating, based on the signature, for the current measurement offset error in a closed-loop using a feedback path.

Abstract: A method for compensating parameter imbalance induced current harmonics in a synchronous motor drive includes reading an output current signal and extracting, based on the output current signal, a signature of a parameter imbalance corresponding to the synchronous motor drive. The method also includes compensating, based on the signature, for the current harmonics induced by parameter imbalance in a closed loop using a feedback path.

Abstract: Technical solutions are described for controlling operation of an inverter to manage voltage upon a direct current (DC) bus and regenerative power (current) provided to a battery. A control system and method are provided to control operation of an electric machine using a controller. More specifically, the controller is configured to calculate a current-based torque limit to satisfy a regenerative current limit, and a voltage-based torque limit to satisfy a voltage limit constraint of the DC bus. The controller is configured to calculate a torque limit to satisfy the regenerative current and voltage limits of the DC bus, and to command a plurality of switches within the inverter to generate a direct-axis current from the electric machine corresponding to a torque demand and according to the torque limit. The proposed system and method provide for motor current that exceed a demagnetizing current limit of the electric machine.

Abstract: 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.

Abstract: 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 supply current-based torque limit based on a supply rating, to supply current to the inverter, of the DC bus; determining a regenerative current-based torque limit based on a receive rating, to receive current from the inverter, of the DC bus; determining a final torque limit based on the voltage-based torque limit, the motor current-based torque limit, the supply current-based torque limit, and the regenerative current-based torque limit; determining a limited command torque based on a torque command and the final torque limit; and calculating at least one current command based on, at least, the limited command torque.

Abstract: A method of controlling operation of an electric machine includes: calculating 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; calculating a current-based torque limit based on a motor current limit; determining a final torque limit based on the voltage-based torque limit and the current-based torque limit; determining a limited command torque based on a torque command and the final torque limit; and generating at least one current command based on, at least, the limited command torque. A control system for controlling operation of an electric machine is also provided.

Abstract: A method for controller a multiphase electric machine includes, in response to a determination that a phase of the multiphase electric machine is in an open circuit condition, determining a desired torque to be generated by the multiphase electric machine and retrieving, based on the determination that the phase is in the open circuit condition and the desired torque, a set of current values to be applied to each of the other phases of the multiphase electric machine to achieve the desired torque. The method may also include applying respective current values of the set of current values to corresponding ones of the other phases of the multiphase electric machine, the set of current values being determined based on a model of the multiphase electric machine that includes the phase is in the open circuit condition.

Abstract: An embodiment of a control system includes a current command module configured to receive a torque command and output a current command for controlling a direct current (DC) motor, and a supply current limiting module configured to receive a supply current limit as an input and actively compute a motor current limit based on the supply current limit, the supply current limiting module configured to limit the current command based on the motor current limit.

Abstract: Systems and methods for detecting a current measurement gain error in a current measurement system is disclosed. The method includes reading an output voltage signal, extracting a signature of a current measurement gain error from the output voltage signal, detecting an existence of the current measurement gain error based on the signature, and responsive to detecting the existence of the current measurement gain error, identifying a diagnostic voltage phase in which the current measurement gain error exists.

Abstract: Improvements to a power input circuit of an electric motor drive system are provided. The power input circuit is provided between a power source (e.g., battery), and a load (e.g., an inverter and a motor in the electric motor drive system). The power input circuit can comprise controllable switches for reverse polarity protection and isolation of the inverter under supply short circuit condition. In addition, an improvement to a power input circuit can comprise connection of a power supply (e.g., voltage regulator) to the external power source input side of a reverse polarity protection circuit in the power input circuit to mitigate against microcontroller restart from post-failure shutdown condition. Connection of a low-power diode in series with the voltage regulator also provides for reverse polarity protection.

Abstract: A system and method for improved anti-windup that minimizes supply current draw under voltage saturated current control operation of synchronous motor drives are provided. The system and method use a voltage limiting module configured to receive a pre-limit voltage command and generate a post-limit voltage command when the motor control system reaches configured threshold; and an anti-windup module configured to determine a voltage difference between the post-limit and pre-limit voltage commands, and compute an anti-windup feedback current using the voltage difference and compensation gains selected to minimize supply current. The compensation gains comprise a gain matrix of values selected to move a motor current trajectory toward a null motor current vector, and the anti-windup module multiplies the gain matrix values by the voltage difference. The anti-windup feedback current and an input current command are then added and provided as an input to the controller.

Abstract: Systems and methods, for controlling an output torque of a permanent magnet direct current (PMDC) machine includes a PMDC motor that includes a plurality of winding sets and a controller. The PMDC motor is configured to generate the output torque. The controller is configured to: determine, for a first winding set of the PMDC motor, a first voltage command based on a first input torque command signal and a back-EMF drop voltage of the first winding set; determine, for a second winding set of the PMDC motor, a second voltage command based on a second input torque command signal; and selectively control the PMDC motor according to the first voltage command and the second voltage command.

Abstract: Technical solutions are described for disturbance feedforward compensation technique for improving the disturbance rejection properties of a closed loop position control system using a cascaded control structure with an inner velocity and outer position control loops. According to one or more embodiments, a system includes a position controller that receives an input rack-position command, and a measured rack-position, and computes a velocity command based on a difference in the input rack-position command and the measured rack-position. The system further includes a velocity controller that receives the velocity command, and a measured motor velocity, and computes an input torque command based on a difference in the velocity command and the measured motor velocity. The system adjusts a position of a rack by generating an amount of torque corresponding to the applying the input torque command to a motor.

Abstract: Technical solutions are described for controlling operation of a multiphase electric machine using a signal generator configured to generate n number of duty cycle signals of a combination pulse width modulation (PWM) scheme comprising of a continuous PWM scheme and a noncontinuous PWM scheme, with n being an integer greater than 3. A blending coefficient value determines relative weights of each of the continuous and noncontinuous PWM schemes in forming the combination PWM scheme. A blending function determines relative weights of each of the continuous PWM scheme and the noncontinuous PWM scheme used to generate the duty cycle signals. The bending function is calculated piecewise based on a difference between the blending coefficient value and two threshold values. The signal generator uses each of the duty cycle signals to control switching of a DC power to a corresponding phase of the multiphase electric machine.

Abstract: Technical solutions are described for disturbance feedforward compensation technique for improving the disturbance rejection properties of a closed loop position control system. According to one or more embodiments, a steering system includes a position controller that generates a torque command based on an input rack-position command and a measured position command. Further, a disturbance estimator that estimates a rack force acting on a rack, and an adder generates an adjusted torque command by adding the rack force that is estimated into the torque command. The steering system further includes an actuator that positions the rack according to the adjusted torque command.

Abstract: Technical solutions are described for preventing controller windup in a motor control system. An example system includes a first anti-windup module that receives a commanded voltage and a limited voltage command. The limited voltage command is applied to an electric motor, where the first anti-windup module generates a first modified current command by modifying a current command that is applied to the motor control system. The modification is based on a ratio of the commanded voltage and the limited voltage command. The system further includes a second anti-windup module that receives the commanded voltage and the limited voltage command. The second anti-windup module generates a second modified current command by modifying the first modified current command. The modification based on a difference between the commanded voltage and the limited voltage command.

Abstract: A method for detecting an imbalance in a synchronous motor drive, the method including reading an output voltage signal, and extracting a signature of a parameter imbalance from the output voltage signal. The parameter imbalance is in the synchronous motor drive. Responsive to extracting the signature of the parameter imbalance, the method further includes identifying a certain parameter having the parameter imbalance based on an operating condition of a synchronous motor controlled by the synchronous motor drive, and determining at least one phase of the synchronous motor in which the certain parameter is manifesting the parameter imbalance.

Abstract: A method for compensating parameter imbalance induced current harmonics in a synchronous motor drive includes reading an output current signal and extracting, based on the output current signal, a signature of a parameter imbalance corresponding to the synchronous motor drive. The method also includes compensating, based on the signature, for the current harmonics induced by parameter imbalance in a closed loop using a feedback path.

Abstract: A method of controlling a motor that generates an output current from an input voltage command. The method receives, from the motor, the output current that includes a direct-axis portion and a quadrature-axis portion, the output current being received as feedback current. The method determines a compensated voltage command by applying, to the feedback current, first gain factors and an inverse of second gain factors. The first gain factors decouple the d-axis portion and the q-axis portion of the compensated voltage command. The inverse of the second gain factors allow the compensated voltage command to be filtered in a manner that preserves decoupling between the d-axis and q-axis. The method determines the input voltage command for the motor by applying the second gain factors to the compensated voltage command to cause the motor to generate the output current with reduced influence of variations of operating parameters of the motor.