Five-leg AC-AC power converter: structure, modeling and control

In this paper, a five-leg AC-AC power converter is proposed to supply a three-phased induction machine from the AC grid. It allows a reduction of the leg number in comparison with the classical AC-AC converter with a three-leg controlled rectifier and a three-leg inverter. This original structure can be viewed as a rectifier and an inverter coupled by a common leg and can be considered as a multi-machine multi-converter system. A specific control is developed in order to keep independence of both equivalent converters. A unity power factor control and a machine vector control are implemented. Simulation results validate the power structure and its associated control. A comparison with the classical six-leg structure points out the limitations of this original converter and its interest in degraded operating