An EMC performance improvement method for three-phase half-bridge converter drive power supply

Abstract

Analyze the electromagnetic interference (EMI) of the primary circuit of the switch tube driving power in the three-phase half-bridge converter, and study how to improve the electromagnetic compatibility (EMC) performance. The high-frequency EMI source caused by high-speed switching in the three-phase half-bridge converter is analyzed and quantitatively calculated. The high-frequency conduction model of the three-phase half-bridge converter and the driving power supply is established. Through the establishment of a high-frequency model, it is pointed out that EMI sources cause three interference conduction paths to the driving power supply: conduction paths I and II between the primary circuit and the driving power supply, conduction paths III between the driving power supply, and use the high-frequency model to obtain three conduction paths Based on the equivalent high-frequency circuit of the channel and the corresponding transfer function, a general method for suppressing three kinds of interference and improving the EMC performance of the drive power is proposed based on the transfer function. The experimental results show that the interference between the driving power supplies is the direct interference. The interference can be significantly reduced by paralleling the capacitors in the ambitious power load.

Keywords

• Three-phase half-bridge converter
• Electro-magnetic compatibility (EMC)
• Common mode voltage
• High-frequency conduction model