This thesis proposes a direct self-control (DSC) method for an interior permanent magnet synchronous motor (IPMSM) with the constant switching frequency. The limitation of the conventional DSC method, which has the characteristics of low switching frequency and fast torque response in high-power systems, is that the switching frequency varies because of operating conditions such as motor speed. In this thesis, instead of the torque hysteresis controller of the conventional DSC method, a torque controller with a constant switching frequency is applied to solve this limitation. The proposed DSC method uses a torque regulator with a proportional-integral (PI) controller and a triangle wave to implement a constant switching frequency. In addition, the proposed DSC method with a constant switching frequency improves the dynamic torque response in the transient state because the dynamic response characteristic is slow in the torque transient state. The effectiveness of the proposed DSC is verified through simulation and experimental results.
