Analysis of the Circulating Current Produced in a System of Two Inverters Connected in Parallel Due to a Difference between the Dead-Times

Abstract

This paper presents an analysis of the circulating current produced as a result of a difference between the dead-times of two voltage source inverters with space vector pulse-width modulation, connected in parallel without galvanic isolation to a load. An algorithm has been identified that calculates the difference between the dead-times through the difference of the homologous output voltages of the inverters. The article proposes a correction of the dead-time imbalance, through proportional-integral control, in order to reduce the circulating current and increase the system’s performance.

Keywords:

• Inverter
• voltage source inverter (VSI)
• space vector pulse-width modulation (SVPWM)
• isolated gated bipolar transistor (IGBT)
• circulating current (ICIR)
• dead-time
• proportional-integral (PI)
• digital signal processor (DSP)
• direct current (DC)