A novel high frequency high voltage (HV) 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 HV transformer with HV 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 1kV 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.

Power packaging technology plays an important role to achieve high performance for high voltage (HV) generator. The HV generator packaging techniques are systematically classified according to different component level packaging and system assembly technology. Both component level packaging and system assembly technology are included in the review and their advantages and disadvantages are discussed. Planar air-core multi-layer printed circuit board (PCB) winding transformer is introduced for HV generator with planar structure. A 450kHz switching frequency HV generator prototype with 310W output power and 1kV output voltage is built in lab. The high frequency HV generator prototype can achieve 1.09kW/L power density at rated 1kV output voltage and 310W full power. 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 enables high voltage generation circuit system compact planar packaging. The litz wire air-core HV transformer behaves higher efficiency and thermal performance with low high frequency AC winding loss.