Feed-Forward Control for Stability Improvement in Cascaded System

Multi-converter power electronics systems are being increasingly used in many applications such as tele-communication systems, international space station, aircraft, electric vehicles, hybrid electric vehicles and fuel cell vehicles. Tightly regulated converter and motor drive systems tend to behave as constant power loads(CPL). Stability of the multi-stage power electronics intensive systems loaded by CPLs is a significant design consideration because of their potential for negative impedance instability. In order to adapt to hybrid electric vehicles (HEV), in this paper the stability of traction system was improved by adding feed-forward control to the main bus voltage. By the demonstration of simulation and experiments, the method presented in this paper can not only reduce the ripple of DC bus but also increase the efficiency of system.