Inverter Nonlinearities Estimation and Compensation for High Performance PWM VSI based AC Drives

AC drives based on pulse width modulation (PWM) voltage source inverters (VSI’s) have many drawbacks, Especially for high performances applications. The inverter nonlinearities such as dead time and power devices voltage drop are one of the main reasons. In this paper a new method to estimate and compensate inverter nonlinearities is presented. The proposed method is based on Model Reference Adaptive System (MRAS). The analysis of dead time and voltage drop effects is firstly performed, where a Logical operator’s based representation is sketched to explain the nonlinearities insertion in a sinusoidal PWM. An MRAS algorithm which involves two active power models in stationary reference frame (α,β) is designed regarding nonlinearities estimation and compensation. The whole system is integrated in Direct Torque Control (DTC) based drive to know features and prove the effectiveness of the proposed method.