Improved Vector Control Method based on Torque Current Integral Balance for Flux-switching Permanent Magnet Machines

Abstract

Flux-switching permanent magnet (FSPM) machines can provide high torque density, strong flux-weakening capability, and high reliability, which makes these machines attractive in electrical drive systems. FSPM machines always employ different control methods, such as the vector control (VC) and direct torque control (DTC) methods. These methods exhibit different electromagnetic torque dynamic performances; hence, the dynamic performances of their rotor speeds are different. However,the proportional integral (PI) controllers of the speed loop in these methods are linear regulators, which hardly guarantee the optimal dynamic performance of the rotor speed. This causes the rotor speed to have several adjustments, overshoots, and a relatively long recovery time during the response to a sudden load change. Therefore, to achieve the optimal dynamic trajectory of rotor speed and maintain the excellent performance of the steady-state simultaneously, a torque-current ( Iq ) integral balance (IQIB) method, which can eliminate the restriction of the PI controllers on the dynamic performance of the rotor speed, is investigated for the VC system of FSPM machines. In the dynamic process, a group of optimal switch vectors is obtained to achieve the shortest recovery time and the minimum number of adjustments for the rotor speed without overshoot, thereby achieving an optimal dynamic performance for the system. Comparative experiments between the IQIB-based VC, VC, DTC, and improved DTC are conducted, and the accuracy and effectiveness of the proposed method are validated.