Model reference adaptive control-based adaptive current control scheme of a PM synchronous motor with an improved servo performance

A model reference adaptive control (MRAC)-based current control scheme of a PM synchronous motor with an improved servo performance is presented. Although the predictive current control is known to give ideal transient and steady-state responses among various PWM inverter-fed current control schemes for a PM synchronous motor, its steady-state response may be degraded under the motor parameter variations. To overcome such a limitation, the disturbances caused by the parameter variations will be estimated using an MRAC technique and compensated by a feedforward manner. Thus, the steady-state control performance can be effectively improved, while retaining its good dynamic performance. The proposed control scheme does not require the measurement of the phase voltage unlike the conventional disturbance estimation scheme using observer. This can be an effective way considering the phase voltage contains much harmonics as well as noise. The asymptotic stability of the overall system is proved and the adaptation laws are derived by the Lyapunov stability theory. The proposed scheme is implemented using DSP TMS320C31 and the effectiveness is verified through the comparative simulations and experiments.