Control of a two-stage direct power converter with a single voltage sensor mounted in the intermediary circuit

Controlling a converter requires not only a powerful processors but also accurate voltage and current sensors and fast and precise analogue-digital converters, which increase the cost per kW of the assembly, especially in the low power range. A matrix converter requires less transducers than a back-to-back voltage source converter because of the inherent direct power transfer which doesn´t require a control loop of the DC-link voltage to balance the power of the rectifier and the inverter. On the other hand, two-stage direct power converters (DPC) also perform direct power conversion as the matrix converters but in two stages (AC/DC/AC) without using energy storage in the intermediary circuit. They also offer the possibility to reduce the number of switches compared to the standard single-stage matrix converter. This work presents a new method to control a two-stage DPC providing sine-wave in sine-wave out operation while using a single voltage sensor mounted in the intermediary link between the rectification and the inversion stages and the information of the sign of the input line-to-line voltages, which is needed anyway for the safe-commutation of the rectification stage.