Quick Response Wide Input Range DC-DC Converter for Renewable Energy System

Abstract

The switching power supply must deal with much more tasks than ever in the renewable energy system whose implementation is being promoted. For that reason, the digital control switching power supply is recognized as a solution in such a complex system. Although the digital control can realize a higher performance than the analog control, there is the room to be improved for further development. The delay time caused by the A-D conversion and processing time influences the dynamic characteristics and transient response. Also, the control precision depending on the quantization error leads to the limit cycle oscillation. These issues must be improved in the digital control. In this paper, the quick response wide input range dc-dc converter is presented, which meets the demand on the control precision of output voltage, transient response, and dynamic characteristics that are required for the renewable energy system. The proportional gain is changed to a high value at the beginning of the transient state. It is attenuated smoothly to an initial value which is set to a low value for steady state. A high proportional gain is used for short time in the transient state. In brief, the proposed method can utilize the feedback gain according to the situation and can meet the demand simultaneously. Therefore, the proposed method is effective in such a complex condition occurring in the renewable energy system.