Switched mode converters have been widely employed to reduce the harmonics of the input current and are increasingly focused on the prevention of accidents and failure in the power system apparatuses. It is desirable that the switching frequency of the switch mode converters be set at a high frequency for effective harmonics reduction. High frequency operation, however, causes large switching power losses and degradation of the efficiency of the power conversion. To improve the efficiency, circuit configurations that can equivalently increase the switching frequency or use soft commutation techniques have been discussed.
This paper proposes a new technique for improving the efficiency of single phase high frequency switch mode boost converter. This converter includes an additional boost converter that follows the main high frequency switching device. The additional converter, which is controlled at lower frequencies, bypasses almost all the current in the main switch and the high frequency switching loss is greatly reduced. Both switching devices are controlled by a simple method each controller consists of a one-shot multivibrator, a comparator and an AND gate, and the maximum switching frequency can be limited without any clock generator. The converter works cooperatively in high efficiency and acts as though it were a conventional high frequency switch mode converter with one switching device.
This paper describes the proposed converter configuration, design, and discusses the steady state performance concerning the switching loss reduction and efficiency improvement. and the proposed method is verified by computer simulation.