Comparative study of PMSM Drive systems based on current control and direct torque control in flux-weakening control region

This paper examines the control performance of permanent magnet synchronous motor (PMSM) drive systems based on current control and direct torque control (DTC) when flux-weakening control is applied. The control law in the M-T frame, which is used in the DTC, requires only armature resistance, whereas the control law in the d-q frame, which is used in current control, requires many motor parameters for flux-weakening control. The experimental results clarify the influence of parameter variation on the control characteristics of flux-weakening and torque limiting. The DTC-based motor drive system combined with the control laws in the M-T frame has several advantages, including insensitivity to parameter variation, simplicity of calculation, and stable control.