DC-link shunt compensator for three-phase system with small DC-link capacitor

This paper proposes a control method of DC-link shunt compensator (DSC) located to DC-node in three-phase diode rectifier system. The circuit can substitute for bulky components such as DC reactor filter and DC-link capacitor from conventional three-phase system. Hence the system can be miniaturized and becomes lighter by reducing heavy passive components. DSC supplies harmonic current into diode rectifier system so that the shape of diode rectifier current can be adjusted, and the corresponding ripple power is transferred to floating capacitor. The action of DSC also intends to stabilize the system which has negative impedance characteristic caused by constant power load (CPL). In this paper, the control method is proposed and stability of the system with DSC is also analyzed. The feasibility of proposed method is verified by simulation results.