Design of High Voltage Pulsed Power Supply for HFRC

Abstract

The HUST field-reversed configuration (HFRC) is a field reversed plasma research device based on colliding and merging under design. To increase the parameters of the initial plasma formed in the theta-pinch, the theta-pinch is designed with very high parameters, namely a chamber diameter of 0.6 m, a bias magnetic field of -0.16 T, a preionization frequency of 150 kHz, and a main magnetic field of 0.6 T. To control the plasma formation and ejection, the discharge regulating accuracy for the theta-pinch is required within several microseconds. Thus, a high voltage, high current pulsed power supply with high controllability is required to satisfy the physical design. This article mainly presents the challenges and solutions in the design of the power supply system. First, 18 theta-pinch coils are used for the field generation to reduce the current on each coil, which results in design parameters of 70 kV/86 kA for the power supply. Then, a new topology with two power supply modules connected in series is adopted to feed the coil, which reduces the system voltage level and increases the operational reliability. Besides, hydrogen thyratron is adopted as the pulsed switch, and a corresponding trigger circuit based on insulated gate bipolar transistor (IGBT) is designed to ensure the precise control of the sequential discharge. Experimental tests are also performed on the thyratron and its trigger circuit, and the breakdown delay time is proven to be less than 1 μs. In conclusion, the designed power supply system can satisfy the requirements of high operation parameters and high controllability.