Speed-sensorless DTC-SVM for matrix converter drives with simple nonlinearity compensation

This paper presents a new method to improve the sensorless performance of matrix converter drives using a parameter estimation scheme. To improve low-speed sensorless performance, the nonlinearities of a matrix converter drive such as commutation delays, turn-on and turn-off times of switching devices, and ON-state switching device voltage drop is modeled using p-q-r transformation and compensated using a reference current control scheme. To eliminate the input current distortion due to the input voltage unbalance, a simple method using p-q-r transformation is also presented. The proposed compensation method is applied for high performance induction motor drives using a 3-kW matrix converter system without a speed sensor. Experimental results are shown to illustrate the feasibility of the proposed strategy.