Multisampled Average Current Control of Switching Power Converters

The digital current control method of switching converters studied in this work is based on taking more than one sample per switching period of the instantaneous current error waveform. To correctly regulate the average current value, as well as to simplify the system model, the controller must include a ripple filter. The proposed system includes a new low-phase-lag ripple filter. The whole system is first modelled in the s-domain to easily include the plant dynamics. The validity of the s-domain analysis up to half the switching frequency, once the controller is converted into the z-domain, has been verified by simulating its frequency response and its transient behavior. In comparison with other digital control methods, our approach provides a good general performance with a reasonable level of complexity.