Adjusted current controller for signal-injection based control algorithms

This Paper proposes current controller for signal-injection based control schemes such as parameter identification and position-sensorless control. In conventional current control system with voltage signal-injection, the injected frequency current separation is carried out by BSFs. However the separation is not properly conducted especially during transient state and when the current controller bandwidth is close to injection signal frequency. This distorts transient response and affects stability of current control system. The proposed method estimates the injected frequency current components based on motor model using the injection signal as an input. Therefore the precise signal separation is accomplished even in transient state. Moreover, current controller's stability and dynamic performance are improved significantly. Experimental results are presented to verify the proposed method. Moreover, implementation issues such as time delay and parameters variation is discussed.