A Digital Two-Switching-Cycle Compensation Algorithm for Input-Voltage Transients in DC-DC Converters

In this paper, a new control algorithm is proposed to achieve excellent dynamic performance for dc-dc converters undergoing an input-voltage change. Using the concept of capacitor charge balance, the proposed algorithm predicts the two-switching-cycle duty ratio series to drive the converter back to steady state following an input-voltage transient. The equations needed to calculate the required duty cycle series are presented. By using the proposed algorithm, good transient performance, such as small output-voltage overshoot/undershoot and short recovery time, is achieved. Simulations and experiments are performed using a synchronous buck converter to verify the effectiveness of the proposed algorithm. Results show that the proposed method produces superior dynamic performance over that of a conventional current-mode PID controller.