A new instantaneous torque control of PM synchronous motor for high performance direct drive applications

A new instantaneous torque control strategy is presented for the high performance control of a permanent magnet synchronous motor. In order to deal with the torque pulsation problem of the PM synchronous motor in the low-speed region, new torque estimation and control techniques are proposed. The linkage flux of the PM synchronous motor is estimated using a model reference adaptive control system technique and the developed torque of the motor is instantaneously controlled by a torque controller combining variable structure control with space vector PWM. The proposed control scheme provides the advantage of reducing the torque pulsation caused by the nonsinusoidal flux distribution of the motor. This control strategy is applied to a high torque PM synchronous motor drive system for direct drive applications and implemented by using a software of the DSP TMS320C30. Computer simulations and experiments are carried out for this system and the results demonstrate well the effectiveness of the proposed control strategy.