POWER ELECTRONICS AND CONTROLS FOR AIR-CORE COMPULSATOR

The Center for Electromechanics at the University of Texas (GEM-UT) ha s been engaged in a large scale effort to develop the power electronic s and control systems required to demonstrate a multi-megawatt, full c ontrol, SCR based rectifier/inverter and high power SCR closing switch . The ultimate objective of this development effort is to provide high efficiency switching for self-excitation of air core single phase rot ating machines and to control the delivery of energy to the final load s. The self-excitation process is initiated by a seed current capacito r followed by active rectification of the compulsator ac output into t he field coil. Upon reaching full open circuit voltage, the main closi ng switch is used to initiate current into the rail gun load. After te rmination of the gun current pulse, stored field coil energy is return ed to the rotor via source commutated, full wave inversion. This paper will present theory of operation for the complete rectification and i nversion cycle, SCR selection criteria, overall design strategy and al l available test data. The test results will include the testing of in dividual devices, multiple series/parallel modules, and full system te sting if available. Funding for this effort has been provided jointly by Task C (contract no, DAAA21-86-C-0281) and CCEML (contract no. DAAA 21-92-R-0002).