Characteristics of a novel PWM inverter circuit with a L-C filter connected with DC link

The characteristics of a PWM inverter circuit whose LC filter is connected with each arm of a switching element of the DC link is described. The switching component of the output voltage is reduced compared to the case in which a filter is connected on the AC side. The LC filter on the DC side shows sufficient performance in comparison with the case in which it is connected on the AC side of a conventional inverter. This is because the voltage which is impressed on the filter is of a single polarity. As for the control method, by making the potential of the control circuit coincide with the potential of the DC link, it becomes possible to detect both output voltage and DC link voltage without the use of an expensive isolation amplifier. By replacing the PWM invertor´s LC filter in this way, efficiency and accuracy of detection were shown to be improved