MINIMISATION OF TORQUE RIPPLE OF HYSTERESIS CURRENT CONTROLLED PMSM USING PI-RES CONTROLLER

Abstract

For the better dynamic performance of PMSM & minimum ripples in torque field oriented control (FOC) is implemented. Some intricate methods are applied for controlling & for the better performance of permanent magnet synchronous machine. For highly performed motor drives flux estimation is always important. The rotor flux estimation model is designed using high pass filter (HPF) to solve the problem caused due to integrator applied in the flux estimation. Also phase locked loop (PLL) is introduced in the model. It is known PMSM is used wherever smooth torque is required. But because of some application of power electronics devices in the modelling often reveals the cogging torque that led to ripple in torque. The key drawback of PMSM is that it produces ripples in the induced torque, which are undesirable in these high-performance applications. Torque ripples led to speed oscillations, which cause PMSM servo output to worsen. The ripples in torque produces mechanical vibrations and noise in the machine that decreases the life of machine. The smoothness of torque is considered as the essential requirement for high performance of permanent magnet synchronous motors. As a consequence, the primary issue in PMSM's control problem is ripple minimization. Since many torque ripples are caused by non-ideal back EMF in stators, a number of techniques for reducing ripples caused by this phenomenon have been developed. PI controllers are generally preferred but this got affected by the variations in parameters, load condition and also on speed. To overcome this problem, a resonant controller is introduced in accordance with PI for the minimization of ripples and to get the better performance. The performance of control methods of both PI & PI-RES controller is compared.