Steady-State Dead-Time Compensation in VSI

The performance of Voltage Source Inverter (VSI) is affected by power semiconductor nonlinearities, dead time, and control delay. The compensation of these nonlinear effects is necessary to meet requirements in terms of current quality and high efficiency, especially for grid-connected power conversion systems. In this paper, the effects of nonlinearities are widely analyzed and a new compensation technique for a steady-state current-controlled VSI is proposed. It is based on a step-by-step voltage compensation on the basis of the current error evaluated within each control interval. As a result, a complete compensation is achieved within a whole period of the fundamental. To cope with the zero-current clamping effect, the proposed compensation technique is implemented in a recursive way. For slow-dynamic applications, such as photovoltaic systems, this method allows achieving high performance with very low computational requirements.