High power inverter for X-ray generator using a coreless transformer

A coreless inverter working at high power and medium frequency is described. A parallel scheme is used that causes a voltage resonant waveform across the primary of the transformer. Though the coreless transformer has a relatively low coupling factor, the voltage resonant mode ensures effective power transfer. The circuit configuration and performance are discussed, and the circuit is analyzed. An example is given of an inverter that delivers a continuous power of 60 kW above 5 kHz with an overall system efficiency of 90%.