Predictive Voltage Control of Direct Matrix Converter with Reduced Number of Sensors for the Renewable Energy and Microgrid Applications

This work proposes and investigates a renewable energy distributed generation system involving a matrix converter with an output filter working as a stable voltage supply. This is especially relevant for the stand-alone operation of a renewable energy microgrid where a stable sinusoidal voltage with prescribed amplitude and frequency under various load conditions is the main control objective. A controllable input power factor is preferred. In this paper, the model predictive control is employed to regulate the matrix converter output voltages which in turn are the supply for systems of the following stage. To reduce the number of required measurements and sensors, the work designs observers and makes use of the switch matrix. In addition to the regulation of the sinusoidal output voltages and input power factor, the control scheme deals with the common-mode voltage. The switching frequency is also considered in the controller to reduce the switching losses and keep the average switching frequency constant. In addition, the voltage transfer ratio can be improved at the cost of input current distortion. Supplying DC loads is feasible with this proposed control method. The controller is tested under various conditions including non-linear loads, DC loads and unbalanced input conditions to show it is effective, simple and easy to implement. Simulation results corroborate the effectiveness of the proposed controller and applications.