A Hall Thruster discharge power converter breadboard was successfully developed. The converter is rated at 400 Watts, with a maximum output of 350 Volts or 1.25 Amps. Both voltage and current are real time continuously adjustable from zero to their respective maximums. An arbitrary number of these converters can be paralleled, offering modularity, redundancy and power scaling for application on a range of Hall thrusters from few a hundred watts to several kilowatts. Operational stability and an overall efficiency of 92% was demonstrated over a broad power range, first on a resistive load and then on Busek's 200 Watt Hall thruster. The design, construction and test results are described in this paper with particular attention to the dynamic interaction of the converter and the thruster.