US 11,787,384 B2
Electric drive system and method
Brent S. Gagas, Pleasant Ridge, MI (US); Kerrie M. Spaven, Rochester Hills, MI (US); and Brian A. Welchko, Oakland Township, MI (US)
Assigned to GM Global Technology Operations LLC, Detroit, MI (US)
Filed by GM GLOBAL TECHNOLOGY OPERATIONS LLC, Detroit, MI (US)
Filed on Nov. 22, 2021, as Appl. No. 17/532,258.
Prior Publication US 2023/0159014 A1, May 25, 2023
Int. Cl. B60W 10/08 (2006.01); B60W 10/26 (2006.01)
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
OG exemplary drawing
 
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.