ENERGY RECOVERY CIRCUIT FOR TESTING HIGH AVERAGE POWER SWITCHES

The testing of high average power components for pulsed power applications involves a significant effort to develop a test bed. In addition to the high cost and considerable time required for designing and building, once in operation, the test bed will require a significant electrical power input and a method to dissipate that power. For life testing of components, it is desirable to reduce the input power requirements and reduce load cooling while still maintaining the required testing specifications of the components. For compression stage switches that transfer energy from one capacitor to another, it is possible to build a circuit that will operate the switch at the desired specifications while reducing the required input electrical power by a factor of 10 to 20. Consequently, because the load is not dissipative, the cooling requirements are also reduced by the same factor. In this paper, a circuit for testing high average power components will be presented. Design information will be given to show how to build such a test bed that will operate at an overall power gain, defined as the power the switches operate at divided by the input power, of 10 to 20. In addition, the advantages and disadvantages of this type of circuit will be discussed. The components of each of these stages are required to operate under a wide range of conditions and specifications. For example, the switches must operate simultaneously at the peak charge voltage, peak current, average and rms currents, rep-rate, and duty factor associated with a particular modulator design. Designing a test bed requires a thorough understanding of how the final system should operate and what conditions it places on the system components. FUNDAMENTAL THEORY