Ride through capability of matrix converter for grid connected system under short voltage sag

This paper proposes a FRT (Fault ride through) method of a matrix converter under three-phase short voltage sag. The feature of the proposed method is to control grid reactive current and generator torque at the same time. In order to realize these capabilities, this paper describes a modulation method dividing a control period into 3 modes. The first mode is to turn off all switches and the second mode is a zero vector output. By these 2 modes and utilizing a snubber circuit, the generator torque is controlled during the voltage sag. In the third mode, a non-zero vector is selected to provide the reactive current to the grid. In contrast, this paper also proposes a feedback control of the snubber voltage to obtain the stable ride through operation. From experimental results, the grid reactive current of 0.44 p.u. and the generator torque of 0.7 p.u. are achieved by the proposed method during three-phase voltage sag.