Full-digital control boards for IGBT full-bridge switching converters

In the field of thermonuclear fusion research, the need to implement coil systems supplied to perform local controls of magnetic fluxes or to generate rotating magnetic fields has grown in the past few years. Tens of coils, each one able to produce up to tens of millitesla on a surface of hundreds of square centimeters, have to be independently fed by converters rated for powers of hundreds of kilowatts and bandwidth in the order of hundreds of hertz. The approach for the design of the converter system, described in this article, involving 22 insulated-gate bipolar transistors (IGBTs) full-bridges, was a semi-custom solution. It is based on the utilization of a well-tested and optimized industrial product for the power section, including the IGBTs driving signal board and the development of a new digital control board. This choice is also in line with the present trend in power-electronic technology that suggests using as much standardized subassemblies as possible and customizing them for different applications.