On the DC inductors size reduction in a multi-cell topology based on current source converters by means of magnetic couplings

This work deals with a multi-cell topology based on current-source converters based power cells. The main disadvantage of this configuration is the bulky DC inductor required in each cell which must be designed in order to compensate the oscillating power drained by the single-phase inverter. In order to avoid the use of a large DC inductor, the use of magnetic couplings among DC links of different power cells is considered. Additionally, active front end rectifiers are used in order to control the DC current and ensure a unitary displacement power factor in each power cell. A control scheme based on non-linear controllers is proposed in order to control each cell in a decoupled way. The topology feasibility is tested experimentally, while the control scheme performance is tested by simulation, showing that it is possible to obtain an excellent overall input current quality and a load voltage with lesser dv/dt than the classic multi-cell topology, reducing the requiered DC inductor from 400 mH to 30 mH for the studied case.