High power wide bandwidth inverter output filter design for various operating frequencies and diverse waveforms

An output filter design is presented for high bandwidth high power inverter in this paper. Various filter topologies are compared to eliminate the switching frequency components effectively while generating various output voltage waveforms up to 10 kHz without distortion. This ultimate design consists of an R-C series branch connected in parallel with the C of conventional L-C filter resulting in the lowest THD at the output voltage for sinusoidal waveform generations compared to other conventional filter techniques. For non-sinusoidal waveforms, e.g., triangular signals, and square signals, the proposed filter follows the shape of the commanded waveform very closely. Analysis and experimental verifications of the system are provided with high bandwidth (60 Hz to 10 kHz) inverter where switching frequency is set to 150 kHz using silicon carbide devices. Experimental results illustrate the effectiveness of the ultimate filter design in generating sinusoidal, square and triangular wave-shapes at wide range of frequency with the fixed value of filter components. Furthermore, the designed filter helps in limiting the current through the inverter within a tolerable boundary. The ultimate filter design is an outstanding candidate in high bandwidth converter applications operating at high power levels.