A new hybrid control method for multi-cell choppers. Application to power renewable energy systems

The growing development of renewable energy opens new perspectives in the use of power converters, both in terms of technology and control. Unfortunately, conventional choppers set some serious problems, even those using “parallel or series multicell” technology. Indeed, the main problem in parallel multi-cell choppers is the possible imbalance of the currents in each cell. This may be due to the components imperfections (resistors, inductors) and/or to the circuits control (the signals have not exactly the same duty cycle). In this paper we propose a new generation of parallel multi-cell choppers specially designed for renewable plants. A reconfiguration of the control is proposed in response to a variation between the current branches. Numerical simulation results are presented and discussed to validate the proposed model.