Motor driving/braking control scheme with integration of multiple driving components

Abstract

AbstractThis paper develops a modular multilevel inverter which integrates driving/braking control schemes in a unit for electric vehicles. The multiple driving components are used to balance surge voltage/current across the last stage power MOSFETs due to abrupt back electromotive force (EMF) generated by the permanent magnet synchronous motor (PMSM). A fundamental unit of the motor driver generally consists of multiple power MOSFETs connected in series/parallel with a braking resistor. These units can be assembled according to the design. In practice, when a PMSM is driven due to inertia rotation, it becomes a power generator which would induce back EMF caused by magnetic induction when a braking command is applied to the driver. If one tries to increase braking effect by reversing driving torque with any approaches for immediately or fast stopping the rotating motor, it commonly leads to switching element breakdown due to the surge counter EMF. In this paper, with the expandable series–parallel design of the inverter circuit, surge voltage/current is dispersed in a balanced manner. Compared with conventional three‐phase motor driver design, the proposed one possesses better durability. Also, it reduces hardware cost since it allows low‐grade power components to be used in the high‐power motor drivers.