High Frequency High Voltage Generation with Air-core Transformer

A novel high frequency high voltage (HIT) generator circuit with air-core transformer is proposed in this paper to achieve high power density packaging structure and compact size advantages. Planar multi-layer printed circuit board(PCB) winding and litz wire wound winding structure are investigated for air-core HV transformer. The electrical design of air-core ITV transformer with ITV multiplier circuit based on 1.2kV SiC Schottky diode are introduced. A with 450 kHz switching frequency HV generator prototype with 310W output power and I kV output voltage is built in lab. The litz wire air core HV transformer prototype is built to compare the efficiency, thermal performance and size with planar air-core HV transformer. The planar PCB air-core transformer based on HV generator can achieve 80.5% efficiency and 1.09kW/L power density. The litz wire wounded transformer based HV generator provide 89.0% efficiency and around 0.53kW/L power density. The design with planar PCB air-core transformer enable high voltage generation circuit system compact planar packaging. The design with litz wire air-core HV transformer behaves higher efficiency and thermal performance with low high frequency AC winding loss.