A cascaded H-bridge converter for a new type of the VLF high voltage generator

This paper presents a new design of a new type of the very low frequency (VLF) high voltage generator. A new structure of the VLF generates is implemented using multilevel voltage source converter in cascaded H-bridge configuration for 0.1 Hz sinusoidal waveform generation. It consists of two main parts, a modulation unit and a high voltage switching unit. The modulation unit compares the 0.1 Hz of sinusoidal waveform with the 10 kHz of carrier waveform. The switching unit consists of 6 H-bridge modules and phase disposition (PD) multicarrier modulation scheme to generate 13 levels of PWM signals. The cascaded H-bridge converter can convert the high voltage direct current (HVDC) to the multilevel step pulse signal and filtered to the sinusoidal waveform at 0.1 Hz with a low-pass filter. The experimental result of this circuit has total harmonic distortion (THD) value less than 5% according to the IEEE 400.2 standards.