Design and development of a Marx generator based 40kV pulsed power supply for non-lethal electric fence

Abstract

A non-lethal electric fence is an effective tool for security. Non-lethal electric fence employs high voltage (several tens of kV) pulses of short (micro-seconds) duration at rate of few pulses per second. Moreover the electric current and energy transferred to the load is controlled below certain limits to ensure non-lethal and non-injurious features. Fence energizer, which is essentially a high voltage pulsed power supply (HVPPS), is the pivotal part of the fence system. Among different HVPPS schemes, Marx generator is superior being reliable and energy efficient. However, it was never used for low power applications such as electric fencing. This work investigates potential of Marx generator in low power applications in general and as energizer for a non-lethal electric fence in particular. Specifically, a Marx generator is designed and implemented for a 40kV electric fence. Other design parameters include 220V ac input, output pulse duration of 1μs–15μs, repetition rate of up to 100 pulses per second, stored energy of 80J and release of energy less than 20mJ per pulse. A complete design is presented here for these specifications with validation in simulation. The design is then implemented using semiconductor switches and electrolytic capacitors for 100 stages of Marx voltage multiplier. The implemented system is tested through air-breakdown test and output pulse is measured through a capacitive voltage divider.