In this paper, an analysis of output current ripple of three-phase PWM inverters with discontinuous modulation is presented. The analytical expressions for discontinuous modulation injection signal are derived. It is followed by derivation of rms value of output current ripple of three-phase PWM inverter as a function of modulation index. Analysis of the influence of injection signal phase shift of the rms output current ripple three-phase PWM inverter is given. It is shown that at the same switching frequency with sinusoidal PWM, the discontinuous PWM produces lower rms output current ripple at high modulation index. A 30° lag phase shift results in lower rms output current ripple. Phase shifting from symmetrical discontinuous PWM gives lower modulation index. Simulation results are included to verify the derived expressions
