A modified flux weakening direct torque control for open winding PMSM system fed by hybrid inverter

Abstract

To extend the constant power range and enlarge the output power of permanent magnet synchronous motor (PMSM) system fed by a single power source, an improved direct torque control (DTC) strategy is proposed for the open winding PMSM (OW-PMSM) system fed by hybrid inverter. The hybrid inverter system is composed of a main inverter powered by a DC voltage power source and a compensation inverter powered by a floating capacitor. A modified strategy using the main inverter voltage as the feedback is proposed to maintain the maximum voltage of main inverter and modify the stator flux linkage reference for the flux weakening operation. Moreover, the voltage references for two inverters are distributed appropriately to extend the constant power range and enlarge the output power of the OW-PMSM. Simulation results verify the effectiveness and superiorities of the proposed strategy.

Topology and control algorithms for a permanent magnet synchronous motor as a part of a vehicle with in-wheel motors

“…The use of such a connection scheme provides for: extending the speed range of the PMSM by compensating the counter-EMF of the electric motor [23]; the possibility of backup switching to the"star" mode in case of failure of one inverter when feeding the auxiliary inverter from the battery or from the common with the main converter' source [24]; availability of additional power source with a possibility of its reservation [25]; possibility to increase a voltage level applied to the PMSM in case of absence of both boost converters and additional power sources [26,27]; decrease in amplitude of current ripple [28]. Papers [29] consider the use of a floating bridge capacitor as a secondary energy source for the topology with two inverters. Based on a comparative analysis of the use of different energy sources to power the auxiliary inverter, presented in [30], the PMSM topology using a floating bridge capacitor is the most promising solution for use in a vehicle, because, in comparison with topologies using a single energy source, does not contribute to zero sequence currents, and in comparison, with systems where the auxiliary inverter is powered from an additional accumulator.…”