摘要:
PWM methods and apparatus are provided for loss minimized control of AC motors taking into consideration inverter non-linear limitations. The method comprises providing a voltage to the AC motor based on a switching cycle, adding a duty cycle of a zero vector to each phase leg of the switching cycle when a duty cycle of a first phase leg of the switching cycle is less than a minimum duty cycle, and subtracting the duty cycle of the zero vector from each phase leg of the switching cycle when a second duty cycle of a second phase leg is greater than a maximum duty cycle. The minimum duty cycle and maximum duty cycle indicate distortion regions.
摘要:
Methods and apparatus are provided for modifying a pulse width modulation signal controlling a voltage source inverter. The method comprises the steps of determining a duty cycle of the signal, clipping the duty cycle when a modulation index is greater than a minimum modulation index and less than a maximum modulation index, clipping the duty cycle when the modulation index is greater than or equal to the maximum modulation index, and transmitting the duty cycle to the voltage source inverter. The minimum modulation index indicates a distortion range.
摘要:
A method for controlling an inverter uses sequences of predetermined states where each state uniquely corresponding to a set of control signals provided to the inverter that is coupled to a motor. The method includes repeatedly applying a first center null timing sequence of the states while monitoring a zero crossing condition and then changing the repeated application of the first center null timing sequence of the states into a repeated application of a second center null timing sequence of states when the monitoring detects a zero crossing condition. The repeated application of the first center null timing sequence sequentially provides the inverter with a first predetermined sequence of sets of control signals. The monitoring of a zero crossing condition monitors for a zero crossing condition in an electrical current flowing between the inverter and a terminal of the motor. The second center null timing sequence defines a second predetermined sequence of sets of control signals.
摘要:
Methods and apparatus are provided for controlling AC motor torque output. The method comprises the steps of producing a current based on a first comparison of a fundamental output frequency of the AC motor with a predetermined frequency and a second comparison of a magnitude of a commanded current with a predetermined DC current, and supplying the current to the AC motor.
摘要:
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.
摘要:
A method for controlling a traction power inverter module (TPIM) in a vehicle includes determining a commanded output torque of the motor using a controller. The method further includes controlling the TPIM and motor using a discontinuous pulse width modulated (DPWM) signal when the commanded output torque is less than a calibrated torque threshold. A continuous pulse width modulated (CPWM) signal is used when the commanded output torque is greater than the threshold. The method may include determining a direction of a change in the commanded output torque, and controlling the TPIM, via the controller, using the DPWM signal only when the commanded output torque drops below a predetermined hysteresis level. A vehicle includes a traction motor producing a motor torque for propelling the vehicle, an ESS, a TPIM, and a controller configured as noted above.
摘要:
A method of detecting a phase winding fault in a multi-phase electric machine is executable via a motor controller, and includes measuring feedback signals of the machine, including each phase current, and generating reference phase voltages for each phase. The method includes calculating a predetermined voltage value using the feedback signals and reference phase voltages, and comparing the voltage value to a corresponding threshold to determine the fault. A control action is executed when the voltage value exceeds the corresponding threshold. The voltage value is one or more of: a ratio of a normalized negative sequence voltage to a modulation index, an RMS voltage for each phase, and total harmonic distortion of each phase current. An apparatus detects the fault, and includes a motor controller and an algorithm as set forth above. The apparatus may include a voltage inverter for generating a multi-phase alternating current output for powering the machine.
摘要:
Method and systems for testing an electric motor are provided. A switching circuit coupled to the motor is operated in a first mode causing current to flow through the motor such that the motor is actuated with near zero torque. A magnitude of the current is repeatedly adjusted between first and second values. The current flow through the motor is monitored.
摘要:
A method for controlling a traction power inverter module (TPIM) in a vehicle includes determining a commanded output torque of the motor using a controller. The method further includes controlling the TPIM and motor using a discontinuous pulse width modulated (DPWM) signal when the commanded output torque is less than a calibrated torque threshold. A continuous pulse width modulated (CPWM) signal is used when the commanded output torque is greater than the threshold. The method may include determining a direction of a change in the commanded output torque, and controlling the TPIM, via the controller, using the DPWM signal only when the commanded output torque drops below a predetermined hysteresis level. A vehicle includes a traction motor producing a motor torque for propelling the vehicle, an ESS, a TPIM, and a controller configured as noted above.
摘要:
Methods and systems are provided for reducing torque ripple in an electric motor. A method comprises receiving a torque command and determining a cancellation current command based on the torque command. The method further comprises generating a harmonic cancellation command based on the cancellation current command, wherein the harmonic cancellation command compensates for a phase shift and an attenuation introduced by a current regulated control module coupled to an inverter coupled to the electric motor. The method further comprises providing the harmonic cancellation command to the current regulated control module, wherein the current regulated control module is configured to control the inverter in response to the harmonic cancellation command and the torque command.