Unity power factor three-phase diode bridge AC-DC converter with soft switchings

This paper presents a unity power factor three-phase AC-DC utility interface which employs a soft switching active snubber network to provide a method of solving the device switching loss and switch stress problems of high frequency operation. This allows much higher power and frequency combinations with the goal of reducing the input current harmonics and filter size. The concept is verified by computer simulations. The detailed descriptions and analyses of the circuit operation, and design considerations are also presented and discussed in this paper. The circuit is especially suitable for high power adjustable speed motor drives, UPS, and switch-mode VAr compensator applications to meet the current harmonics limits of IEEE-519.<>