A 25kV, 250kW Multiphase Resonant Power Converter for Long Pulse Applications

Abstract

Summary form only given. This paper considers the design of a long-pulse modulator supply rated at 25 kV, 10 A (250 kW peak power, duty ratio 10%, 25 kW average power, pulse length ~ 1-2ms). The supply is based on direct modulation of a multi-phase resonant power supply, fed by an active rectifier. The objectives of the development are to produce a compact power supply, with low stored energy and with high power quality at the utility supply. The paper provides a brief overview of the technology, followed by a discussion of the design choices. Results from the laboratory prototype are included. The output load specifications for high voltage DC power systems are becoming increasingly more demanding. In addition, the impact of such systems on the electricity source is becoming more tightly regulated through power quality directives. These regulations set limits, for example, on the allowable individual harmonic current amplitudes and on "flicker" caused by transient load demands - the latter is particularly important for "long-pulse" (~ \ms) modulators. The requirements above have to be met while still providing higher reliability to a higher specification at lower cost. A situation has now been reached where modulators based on existing approaches cannot meet these specifications and stay within acceptable cost and size limits. This demands that new approaches be taken to provide the power supplies needed for such applications. The research presented here addresses this need. The majority of current generation power supplies in use in high-energy physics accelerator systems are based upon 50/60Hz, line frequency technology that demands large transformers and capacitors in order to satisfy the stringent specifications. Generally, in the past, this bulk may not have been a serious inconvenience because there has been adequate space available. Current and future applications however, demand a reduction in power supply size. Previous publications have presented results showing the prototype converter operating at full power but at a reduced (2kV) output voltage . The high voltage transformers have now been installed. The first results at high voltage operation will be presented.