Modeling design for a matrix converter with a generator as input

Abstract

This paper proposes a model and design based on the behavior of a matrix converter and a generator. Presently, applications for grid connection have been considered widely such as micro-gas turbines, wind power systems, engine generators and so on. However, a very large impedance power supply such as the generator has not been sufficiently examined. Especially the PM generator which is used in various applications has large synchronous reactance. To perform a simple characteristic analysis, an ideal mathematical model excluding switching parts is introduced. An input filter characteristic is discussed by using an ideal mathematical model. Thus, the cause of the unstable behavior is clarified. In order to verity about the stability operation, a proposed stability control on the rotating frame is applied to the generator. The proposed method can control the generator current and the output voltage regardless of the generator speed. In addition, a control of optimal input power factor is proposed to obtain maximum modulation index of the matrix converter. Moreover, the fluctuation in the output voltage is able to compensate by the proposed voltage compensation method. This paper confirms the validity of the proposed strategy by simulation and experiment. The large oscillation on the generator terminal voltage and current are suppressed by the proposed stability control. Moreover, the proposed control achieves stability at motor load 1.5kW and 3.7% of the input current THD.