Flux-weakening control of PMSM considering inverter nonlinearity

This paper proposes an improved flux-weakening operation for PMSM considering inverter nonlinearity. For the flux-weakening operation, full utilization of an available voltage applied to a motor is very important. One of critical information for the flux-weakening control is an actual motor input voltage, which is commonly replaced by a command voltage. However, this can be different from the actual voltage due to inverter nonlinearity. In the proposed method, the disturbance voltage due to inverter nonlinearity is estimated by using an observer to identify the actual voltage applied to a motor. This voltage allows an accurate optimal flux-weakening operation, which improves torque capability in the flux-weakening region. The effectiveness of the proposed algorithm is verified by simulation and experiments.