A High-Power Pulsed Corona Source for Pollution Control Applications

Abstract

The system comprises an all solid-state compact nanosecond pulser and a plasma reactor. The pulser makes use of magnetic compression techniques. Owing to a fast switching at the feed of the HV transformer provided by an ABB GCT switch, one compression stage suffices for the forming of 45-kV, 100-ns pulses across a 120-resistive load at a PRF of up to 1 kHz; the risetime is 15 ns. Plasma reactor is capable of handling both gases and liquids by adding small amounts of atomized water to the gas discharge, in the case of gas, or atomizing polluted liquid itself. In both cases, the treatment is conducted in heterogeneous media. Circuit analysis of compressor and charging system accounting for nonlinear processes in magnetic switches and numerous parasitic parameters is presented. Mechanical and electrical designs are detailed. Typical voltage and current waveforms, volt-ampere characteristics, corona discharge appearance, and light emission characteristics are presented. At operation on a resistive load, the compressor efficiency was found to be approximately 80%, which allowed for air cooling. The experimental results obtained with a resistive load are in fair agreement with the circuit simulation. A novel magnetic compressor circuit improving the coupling to PC discharge is proposed and evaluated.

An Industrial Streamer Corona Plasma System for Gas Cleaning

“…For the 120 kW average power modulator described in [14], the efficiency is about 50%. The 40-kW average power modulator described in [13] has a efficiency of less then 76%; and for the system described in [22], it is less then 50% for 1-2 kW average power. All systems have considerably lower energy transfer efficiency than the presented one.…”

Characteristics of Magnetic Core in Magnetic Pulse Compression System

“…2) using Eqs. (1) and (2). From the hysteresis loops, it can be seen that (a) the ratio of remnant flux density to saturation magnetic flux density (B r /B s ) is close to 1, and the maximum flux swing over 2.2 T is obtained, which means that this core can withstand larger pulse energy compared to those ferrite cores [4], (b) low core loss under µs level pulse excitation is expected from the narrow area of the hysteresis loop, so it is quite suitable for using in preceding stage saturable transformer, and (c) the eddy current loss, the dissipated energy as well as the leakage current are in direct proportion to dB/dt, therefore the switching performance of this core is poor when it is used in final stage magnetic switch.…”

“…Magnetic switch (MS) [1] used in pulsed-power applications is superior in its high stability, high repetition rate, and long lifetime to electrical discharge switches which have unstable switching and short lifetimes due to electrode deterioration [2]. Recent pulse generators based on the new magnetic pulse compression (MPC) algorithm [2][3][4] have allowed high repetitive operation of MSs with very low losses, and made it possible to use repetitive pulsed power generated by magnetic pulse compressors in practical industrial applications such as water treatment, laser exciters, removal of volatile toxic compounds and decomposition of hazardous gases [2].…”

“…Recent pulse generators based on the new magnetic pulse compression (MPC) algorithm [2][3][4] have allowed high repetitive operation of MSs with very low losses, and made it possible to use repetitive pulsed power generated by magnetic pulse compressors in practical industrial applications such as water treatment, laser exciters, removal of volatile toxic compounds and decomposition of hazardous gases [2]. As the use of magnetic cores has become popular in pulsed power applications, there have been several studies on the pulse magnetic characteristics that are critical for a MPC system [1][2][3][4]. As the pulse width of excitation pulse stages in an MPC becomes shorter, the switching performance of the magnetic switch which is one of the dominant measures for overall performance becomes poor.…”

AC/DC/Pulsed-Power Modulator for Corona-Plasma Generation

“…Unfortunately, the lack of costeffective corona-plasma generation and processing techniques discouraged industries. Nevertheless, three industrial coronaplasma demonstration systems with up to 40-120 kW in average power were recently reported in Japan, Korea, and China [4]- [6]. These systems are based on magnetic compression techniques with pulse duration of 200-500 ns.…”