High-Frequency Bipolar Solid-State LTD Based on a Self-Triggering H-Bridge

Abstract

In pulsed electromagnetic field tumor ablation, a bipolar nanosecond pulsed electric field has obvious therapeutic advantages. This article proposes a bipolar linear transformer drive (LTD) source circuit topology with a self-triggering H-bridge for this application. In this topology, in the absence of a magnetic core reset circuit, high-frequency bipolar pulse output is realized by introducing an H-bridge while keeping the circuit structure simple. A self-triggered H-bridge is formed by cleverly introducing a self-triggered circuit in the H-bridge, which reduces the difficulty of circuit control. There are only two main control signals, and the sources of all the main control switches share the same ground. The self-triggered switches are self-triggered through the energy-taking capacitor, which improves the stability of the switch control. Theoretical analysis and simulation results demonstrated the theoretical feasibility of the above-mentioned topology; thus, an experimental prototype was built to test the key parameters. The entire prototype adopts a modular design, and each module consists of only four self-triggering H-bridges and one nanocrystalline magnetic core. The key parameters of the final designed prototype are as follows: voltage amplitude of ±4 kV, pulse width of 60–260 ns, pulse rising edge of approximately 11 ns, continuous operation at a maximum frequency of 10 kHz, and output of 500 kHz high-frequency nanosecond pulse.