New solid-state Marx topology for bipolar repetitive high-voltage pulses

A novel bipolar high-voltage modulator topology, based on the Marx generator concept, is proposed for high-voltage repetitive pulsed power applications. The proposed topology is a generalized version of the negative and positive all-solid-state Marx modulator concepts, which takes advantage of the intensive use of power semiconductor switches to increase the performance of the classical circuit, strongly reducing losses and increasing the pulse repetition frequency. Additionally, the proposed topology enables the use of typical half-bridge semiconductor structures while ensuring that the maximum voltage blocked by the semiconductors is the voltage of the capacitor in each stage. Due to semiconductor topology used the output voltage is very flexible. Hence, it is possible to change from negative to positive unipolar to bipolar pulse, with different duty cycles and different switching patterns. Experimental results are presented and discussed. A laboratory prototype with 10 kW peak power, of this bipolar solid-state modulator circuit, was assembled 1200 V IGBTs and diodes, operating with 1000 V d-c input voltage and 10 kHz frequency, giving 2 kV bipolar pulses, 5 A, with 5 mus into a resistive load.