Modulation Method to Reduce Losses in Inverters with LC-Filters

As high efficiency is a crucial parameter for inverters, this paper proposes a modulation method to reduce rms currents and current ripple in inverters with LC output filter. Operating an inverter with a fixed switching frequency, a sinusoidal current with a superimposed triangular current ripple results in the filter inductance. Using the proposed modulation scheme reduces the rms current of the filter inductance by reducing the current ripple with an increased switching frequency. The switching frequency is only increased in the range where ZVS can be achieved for both half-bridge switches. During this time the switching losses can be neglected. Thus, the novel modulation scheme reduces conduction power losses in semiconductors, filter inductance, and capacitors.