Mitigation of conducted and radiated EMI generation in high-frequency switching devices

The purpose of this paper is to investigate the electromagnetic interference (EMI) propagation paths and how to mitigate these generated high-frequency noises in high-frequency switching devices. Both conducted and radiated EMI can be produced when the devices are in operation. This results in restriction of power electronic devices' evolution. In order to effectively reduce EMI generation or overcome EMI problems, an Electromagnetic Compatibility (EMC) regulation should be applied. The conformity to the standard will guarantee the performance and the compatibility of the electrical/electronic devices/equipments to be employed or installed in the sensitive electromagnetic environment. The EMC standard is defined in the frequency range of ISO kHz to 1 GHz: 150 kHz to 30 MHz for conducted emission measurement and 30 MHz to 1GHz for radiated emission one. A switching device connecting to tuner kit (FM radio) is herein focused as an EMI source. The generated noises will be reduced by using grounding and shielding methods. The obtained results will be compared with an EMC standard (EN55022 class B) in order to reveal the effectiveness of the applied EMI mitigation techniques. The analysis and experimental results finally show that the conducted emission can be diminished by using multi-point grounding whereas the radiated emission is effectively reduced by using single-point grounding and shielding, in particular at high frequencies.