EMC of power supply circuits

Power supply circuits based on power conversion using switching operation of power semiconductor devices (switching power supplies) have come to be used in order to achieve energy conservation and equipment miniaturization. While the application range of switching power supplies has expanded and their power conversion performance has improved remarkably, circuits have become higher voltage and higher current, and at the same time, di/dt and dv/dt have also increased. This has made it impossible to ignore the electromagnetic noise caused by parasitic inductance and capacitance in the power conversion circuit. Electro Magnetic Compatibility (EMC), which is the immunity to electromagnetic interference (EMI) caused by electromagnetic noise generated by switching power supplies as well as immunity to electromagnetic noise generated by others, is becoming more important. EMC (Electro Magnetic Compatibility) is important. Ad hoc measures such as inserting ferrite cores in power lines to suppress electromagnetic noise problems in power conversion circuits are time-consuming and costly, and do not provide a fundamental solution to the problem. Funaki Laboratory is conducting research to clarify the mechanism of electromagnetic noise generation in switching power supply circuits and to construct a power supply circuit design theory with electromagnetic compatibility. For this purpose, we are not only designing circuits based on the conventional linear lumped-constant circuits, but also examining how to apply electromagnetic viewpoints such as distributed-constant lines and crosstalk, which take into account wiring structures, etc., and how to apply nonlinearities in semiconductors, dielectrics, insulators, magnetic materials, etc. to power circuit design.

Research work