A novel control strategy of output voltage ripple reduction in Buck converters

DC/DC converters have been tremendously utilized nowadays. In some special applications such as military, aerospace, and precision instrumentation, the output voltage ripple of DC/DC converters has to be maintained in an acceptable level to achieve superior performance. For example, DC/DC converters are tied with inverter for adjustable speed motor controls or renewable energy interface with utility. Traditional way to control DC/DC converters is to use PID controller to adjust desired duty cycle or inductor current. However, when the input is rectified signal or from fuel cell the conventional PID controller can not accommodate this issue due to inherited high frequency ripple of the input. This paper uses the family of Buck converters to demonstrate a novel control strategy to reduce output voltage ripples of DC/DC converters. The control method has been verified by theoretical analysis and simulation results. The proposed method can also be utilized in other types of DC/DC converters. In addition, by achieving output ripple reduction the size of output filter can be reduced as well.