Classification and Comparison of EMI Mitigation Techniques in Switching Power Converters - A Review

Abstract

Power electronic systems such as switching power supplies are accounted as noise sources for other sensitive circuits. EMI caused by power converters can disturb the normal operation of the converter and other adjacent systems. Major research is concentrated on EMI mitigation for power converters in which the main concern is compliance with EMC standards to ensure proper operation of converters and nearby systems. This paper reviews EMI reduction techniques related to switching power converters with emphasis on the conducted EMI. A comprehensive review of significant research works is performed and various methods are thoroughly discussed and compared. Also, a classification of methods is presented. Moreover, converter prototypes are realized which contain several EMI mitigation techniques and their effects are presented via experimental results.

A ZCT Double-Ended Flyback Converter with Low EMI

“…The switch voltage stress of S 1 and S 2 is clamped to the input voltage which prevents fluctuations after turning the switches off. This reduces the electromagnetic emissions of the converter to [12]. To demonstrate that the soft switching condition for the proposed converter has the ability to improve the converter efficiency, the converter efficiency curve is depicted in Fig.…”

“…One of the EMI reduction methods which can be used for this is a Faraday shield. In this technique, the value of the parasitic capacitor between two the sides of the converter transformer is decreased with a piece of aluminum foil placed between the primary and secondary transformer windings [12]. Another simple method to reduce EMI is to use a common-mode choke at the input of the converter.…”

“…In [11], a ZCT single-switch flyback converter with a simple auxiliary cell at the secondary side of the transformer is introduced. The auxiliary switch voltage suffers from voltage spikes at the turn-off instant which affects the electromagnetic emissions [12]. In [13], a double-ended ZCT flyback converter with an auxiliary cell at the secondary side of the transformer is proposed.…”

A New Family of Non-Isolated Zero-Current Transition PWM Converters

“…According to (20), a large n results in a decreasing maximum allowable duty cycle and more voltage stress across D 2 . However, (16) indicates that larger n leads to lower voltage stress across the main switches.…”

“…Moreover, the ZCT condition at turn-on and ZCT-ZVT at turn-off instant result in lower di/dt and dv/dt. Accordingly, the proposed family could potentially improve electromagnetic compatibility (EMC) [20]. Therefore, in addition to the efficiency and soft-switching issues, conducted EMI is evaluated in this work.…”