Novel control scheme of two-switch forward converter for improving light load efficiency of electrical power system in satellite

Abstract

As satellite missions become more advanced, the bus level of the satellite electrical power system has increased. Conventional satellite converters are not suitable for the high bus voltage levels because they have large voltage stress on switches. On the other hand, two-switch forward converter has low voltage stress on switches. As a result, it is an attractive candidate for a low power supply in satellite power systems with high bus voltage levels. However, it operates in hard switching conditions, which can cause low efficiency under light load conditions. To solve this problem, a new control method is proposed in this paper. Under light load conditions with discontinuous conduction mode, the proposed control method reduces switching loss by delaying the turn-off of one switch. Therefore, it improves light load efficiency. The validity of the proposed control method was verified with a 360-400 V input and 15 V/100 W output prototype converter.