An Energy-Based Analysis of High Voltage Resonant-Based Pulsed Low Power Converter for Water Treatment Application

Abstract

Usage of ozone is an effective way of treating wastewater, and the silent discharge technique is one of the most efficient and reliable methods for ozone production. Ozone is generated in a Dielectric Barrier Discharge (DBD) chamber through the silent discharge technique and is powered by a high voltage (in the range of -2.5 kV to -5 kV) pulse generator. The pulse generator has two conversion stages, i.e., a high-frequency pre-processing stage and a pulse-frequency post-processing stage. In a high voltage pulse generator, a significant amount of energy from the input is utilised by the converter’s parasitic capacitance and leakage inductance, which reduces the energy delivered to the load for each pulse cycle. This paper proposes an energy-based analysis exploring the potential usage of the flyback converter-based high voltage pulse generator for an application with power requirements under 150W, and water treatment is such an application. An energy-based approach is appropriate to describe the behaviour of the pulse generator in terms of circulating energy and energy exchanges in each stage and energy exchanges between the two stages (i.e. pre and post-processing stages). The proposed analysis is used to derive the essential parameters of the pulse generator and thereby arrive at an appropriate control scheme for the pre and post-processing stages. The proposed energy-based analysis and the derived analytical expressions of the high voltage pulse generator are verified experimentally for a pulsed output voltage of -5 kV having a Pulse Repetitive Rate (PRR) of 1000 Hz and pulse width of $\mathrm {15 ~\mu \text { s} }$ fed from a 12 V battery source.

Keywords

• Energy-based analysis
• flyback converter
• capacitive load
• programmable pulsed high voltage
• pulse power
• resonant converter