A Three-Phase Four-Wire Inverter Control Technique for a Single Distributed Generation Unit in Island Mode


Min Dai, M.N. Marwali, Jin-Woo Jung and A. Keyhani
Ohio State Univ, Columbus, OH, USA ;

This paper appears in : IEEE Transactions on Power Electronics 
Date: January 2008  


Abstract:
A control technique is developed for a three-phase four-wire split dc bus inverter of a single distributed generation unit working in island mode. The control technique combines an inner discrete-time sliding mode controlled (DSMC) current loop and an outer robust servomechanism controlled voltage loop. The control algorithms are developed under stationary (Clarke's) reference frame and a modified space vector pulse width modulation (MSVPWM) is proposed to implement the algorithm under Clarke's reference frame. The proposed technique achieves voltage regulation with low steady state error and low total harmonic distortion and fast transient response under various load disturbances.  Meanwhile the usage of MSVPWM in a stationary reference frame yields better transient performance under limited dc bus voltage compared to conventional uniformly sampled sine wave modulation in ABC reference frame. In this paper, besides the development and description of the algorithms, a series of discussions, analysis and studies are performed on the proposed control technique, including the L-C filter design issue, frequency domain closed-current loop and closed-voltage-loop responses, and time domain simulations and experiments under various load conditions. All the analysis, simulations and experiments demonstrate the effectiveness of the proposed control solution.