| Abstract |
A new control strategy for the detection of the resonant frequency of a DC-DC converter with a variabletransmission path is used in this paper. Applying a Second Order Generalized Integrator (SOGI) in combinationwith a Frequency Locked Loop (FLL), the primary current of the transmission path is filteredand the orthogonal signal is determined. With the two outputs the current phase angle can be calculatedand the correct switching time is determined by compensation of the signal propagation delay. Based onthis approach a continuous adaption of the dead time between two complementary control signals for thefull bridge is proposed. The importance of the correct dead time is proven by measurements. Furthermore,a new algorithm for power regulation is introduced. Improving the state-of-the-art energy injectionand free-oscillation method, the power transmission can be enhanced and the switching frequency mightbe reduced for low power. |
