Synthesis Of PWM Plus Phase-Shift Bidirectional DC-DC Converters

Bidirectional DC-DC converters can easily control the transfer of power between two DC sources, and will be widely used in applications such as electric vehicles, aerospace power systems, and new power generation system which utilize clean energy. However, there exit three key problems in their applications, which are power density, EMC, and cost. Soft switching is one of key technology to solve these problems. Phase-shift bidirectional DC-DC converter is attractive since it operated with fixed frequency, has small voltage and current stress and can realize ZVS without auxiliary switches. However, it has high current stresses and narrow ZVS range when the amplitude of input voltage is not matched with that of output voltage. Both the range of input voltage and that of output voltage are very wide in applications such as electric vehicles and aerospace power systems.PWM plus phase-shift bidirectional DC-DC converter features reduced current stress, conduction losses, switching losses of semiconductors and wide ZVS range. Actually, PWM plus phase-shift control can be extended to a family of bidirectional DC-DC converters. In this thesis, a technique to synthesize bidirectional DC-DC converter topologies is presented. Operation principle, design of control circuit, loss analysis and experimental results of one PWM plus phase-shift bidirectional DC-DC converter are provided.