Master-Slave Predictive Current-Tracking Approach in Multiswitching Systems

The present paper deals with an innovative approach to control multiswitching converters. The proposed modulation strategy directly controls the external current. Once the switching action is decided by a master routine, the choice of which leg has to be effectively switched is demanded to a separate slave routine. An acceleration algorithm and a maximum leg current protection are also considered. Under the proposed approach, the system bandwidth is related to the global switching frequency equal to the valve frequency multiplied by the number of valves. Consequently both system dynamics and accuracy over external current are greatly improved. An unconventional predictive current tracking technique, characterized by constant overall switching frequency and high dynamic performances, is discussed for a single switching element and extended to multiswitching systems. Details of the proposed control, simulation and experimental results are reported.