Variable Phase Shift Angle-Based Integrated Direct Torque Control of Multiple In-Wheel PM Motors for Distributed Drive Application

To address the cooperative control challenge in the distributed drive (DD) system with multiple in-wheel permanent magnet (PM) motors, an integrated direct torque control (DTC) is presented in this article. It involves the mapping and projection of the control planes of multiple in-wheel motors into a virtual plane, where the integrated control can be realized. And then, in the virtual plane, by exploiting the phase angle differences formed between the motors, the variable phase shift angle (PSA)-based integrated DTC is proposed. In addition, a 1/2 DD system is employed as a case study, on which the concept of PSA control is investigated based on six half H-bridge inverters. Further, the mathematical model for the dual in-wheel (DIW) PM motors is derived, and the PSA adjustment control principle is discussed in detail where the rules of voltage vector synthesis and reference motor selection are given. To validate the efficacy of the control strategy, an experimental platform is constructed by using two distinct types of in-wheel PM motors, and comparison tests of the variable PSA-based control and conventional DTC are conducted under various conditions. The results verify that the proposed control significantly enhances the cooperative performance of the DD systems.