Abstract
Recently, due to the rapid progress in high technology industry, much better power quality is required to meet the need of highly accurate automation machinery. As a result, how to achieve a much better performance for the core power converters has become a popular research topic in power electronics domain. In view of this, a new hysteresis current controller with controllable power factor and bi-directional power flow capability for single-phase multi-level inverters is proposed in this thesis.Owing to the fast response, easy implementation and with bounded errors, the well known two-level hysteresis current controller has been widely used in various applications. However, as far as existing multi-level hysteresis current controllers are concerned, only an intuitive idea is used to choose the multi levels for the controller. It turns out that the resulting current errors will be out of the assigned error bounds around some transition regions of adjacent voltage levels. Hence, the author proposes a novel multi-level hysteresis current controller with sound theoretical basis to improve the above drawbacks. In addition, for easy implementation, the author also proposes an approximate realization method by using three hysteresis bands. This realization can not only keep the current errors within the assigned error bounds for almost all the time but also can avoid the complex calculation of the current error derivatives. Finally, a prototype has been implemented and some simulation and experimental results are also provided for verifying the validity of the proposed control strategy.