Measurement and Mitigation of Conducted Emission for Voltage Phase Controlled Capacitor-Run Single Phase Induction Motor

A TRIAC-based voltage phase speed controller is typically used to control the voltage of the winding of a variable speed single phase induction motor. Transient voltage and highly harmonic current will be produced when TRIAC switches turn on and off. This will result in significantly conducted emissions, causing serious problems concerning the EMI issue. This paper presents a measurement and mitigation method of the conducted electromagnetic interference (EMI) for the voltage phase controlled capacitor-run single-phase induction motor (CR SPIM). The conventional and improved voltage phase controlled schemes, for the speed control of the SPIM driving system are investigated. The measuring results of the common mode (CM) and differential mode (DM) are compared and used to design a power line filter to improve the conducted EMI performance, compliant with the regulatory requirement of CISPER 22/EN5502.