A novel hysteresis current controller to reduce the switching frequency and current error in D-STATCOM

This paper presents a study on a novel hysteresis current controller of a STATCOM (static synchronous compensator) used for reactive power compensation on a distribution network. Hysteresis controllers are intrinsically robust to system parameters, exhibit very high dynamic response and are suitable for simple implementation. But the current control using a conventional hysteresis controller in D-STATCOM has the disadvantage that high switching frequency may happen due to lack of coordination among individual hysteresis controllers of three phases. This will of course increase the switching loss. In addition, the current error is not strictly limited. So, in this paper to reduce the switching frequency and current error, a novel hysteresis current controller in synchronous rotating reference frame is proposed. The presented control system was tested with digital simulation in the Borland C++ program and demonstrates the advantage of the novel hysteresis current controller.