Ternate carrier PWM strategy for improved Z-source inverter

To make boost factor of Z-source inverter independent of the modulation index while the harmonic of output voltage is not increased,a kind of ternate carrier Pulse Width Modulation(PWM) strategy is put forward.The power devices are controlled by comparing three carrier waves with three-phase reference waves.The shoot-through zero state is injected in the time when traditional zero vector works.Then the output voltage wave is not changed.The voltage gain is determined by the DC bias voltage of carrier wave when the modulation index is constant.The voltage stresses on the capacitances and power devices are analyzed and compared with other traditional methods.The Z-source inverter and the improved Z-source inverter are simulated.The results show that this method possesses better control performance.