AC-powered multi-module high-voltage pusle-generator with sinusoidal input current for water treatment via underwater pulsed arc discharge

Abstract

The underwater pulsed arc discharge is one of the effective methods in water treatment applications. In pulsed arc discharge, a pulsed output in the range of 1–10 kV is typically applied across the water treatment chamber electrodes with a gap of several millimeters range between these electrodes, while the pulsed load current is above 1kA. The employed pulse generator should not only be capable of generating a high-voltage level, but also withstand the corresponding high-current stresses. In this paper, a multi-module high-voltage pulse generator is proposed for pulsed arc discharge-based water treatment system. The proposed generator consists of n synchronized groups fed from isolated dc sources, while their outputs are connected in series forming a high voltage pulsed output. Each group consists of m parallel-in parallel-out identical synchronized modules to share the current. Each module consists of a boost converter followed by a Capacitor-Diode Voltage Multiplier (CDVM) which is followed by chopping Insulated Gate Bipolar Transistor (IGBT). Each module is controlled to ensure a regulated dc output voltage across its terminals, a sinusoidal input grid current, and unity input power factor. In the proposed scheme, relatively low-voltage low-current IGBTs and diodes can be employed to generate the high-voltage high-current pulsed output. The simulation results for a 30kW system are presented to show the viability of the proposed approach.