A new current mode control process and applications

A refined stability analysis of constant-frequency current-mode power converters is presented. The authors introduce a new current-mode control method that overcomes the limited duty cycle range of stability. They apply the method to half-bridge and full-bridge converters. A description is given of an improved-performance uninterruptible power supply based on the new control method. The authors have used a two-level modulation in the full-bridge circuit, with high-frequency switching in the four branches of the power circuit. Large protection times are required, with consequent duty-cycle and frequency limitations. The use of a three-level modulation will overcome these problems and permit a reduction of the output filter