CPC B60W 10/08 (2013.01) [B60W 10/26 (2013.01); B60W 2510/244 (2013.01); B60W 2710/081 (2013.01); B60W 2710/083 (2013.01)] | 20 Claims |
1. An electric drive system comprising:
a rechargeable energy storage unit connected to a power inverter via an electric power bus;
an electric machine operatively connected to the power inverter; and
a controller in communication with the power inverter;
wherein a transfer of electrical power between the rechargeable energy storage unit and the rotary electric machine is governed by a pulse width modulation (PWM) switching mode, the PWM switching mode including a non-six-step switching mode and a six-step switching mode;
wherein the controller has a processor and tangible, non-transitory memory on which instructions are recorded, the instructions being executable by the processor to:
determine a rotational speed, a torque command, a torque direction, a bus voltage, and a hysteresis band;
determine a modulation index command in response to the rotational speed, the torque command, the torque direction, the bus voltage, and the hysteresis band; and
command operation of the rotary electric machine in one of the non-six-step switching mode or the six-step switching mode employing the modulation index command.
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