Series inductor compensated load resonant inverter type ozonizer with pulse density modulation control scheme and its evaluations

This paper presents a high-frequency voltage source-fed load-resonant IGBT inverter with a series-compensated resonant inductor for ozonizer applications, which incorporates the power control strategy on the basis of pulse density modulation (PDM). The inverter system configuration is illustrated through the circuit modeling of the silent discharge-based ozone generating tube as well as high-voltage transformer. A state-of-the art ozonizer using a voltage-fed type high-frequency load resonant inverter is demonstrated, and its operating principle is described for driving the ozone generating tube. It is noted that the pulse density modulated series resonant high-frequency inverter using IGBTs makes an ozone generating system simple, thus leading to an improvement in the ozone generation efficiency. Finally, it is proved that the series load-resonant inverter type ozonizer developed in this paper provides stable silent discharge characteristics over a wide output power range from 10% to 100%.