Development of a high frequency and high-voltage pulse transformer for a TWT HVPS

A pulse transformer for a high frequency and high voltage operation had been designed, fabricated, and tested. The high frequency operation of the pulse transformer increases power density. Therefore, it is possible to reduce power supply volume. To produce high voltage output, the transformer should have a high step-up ratio. The step-up ratio is generally limited in pulse transformers due to stray capacitance and leakage inductance. The limit was overcome by winding multi-secondary outputs. Switching frequency of the transformer was 80 kHz. Input and output voltages of the transformer were 265 VDC and 4.1 kV, respectively. Normal operation power of the transformer was 1.7 kW. Maximum volume of the transformer was 200 cm(3). pulse transformers with various winding arrangements are fabricated to check variations in electrical characteristics. In this paper, design procedures and test results of the high frequency and high voltage pulse transformer will be presented. Results of various parameters, such as transformer loss, temperature rise, leakage inductance, distributed capacitance, will be discussed in detail.