Dual switched mode power converter

A dual power converter is introduced which addresses the problem of output ripple and switching losses in a switched power converter. One stage of the power converter is a conventional PWM (pulse-width modulated) converter, and the other stage is a linear source. The linear source controls the voltage directly, and the output current of the linear stage is used to generate the control signal for the switching stage. This scheme is modeled as a two-stage control system, and the overall response is obtained in terms of the individual transfer functions. The PWM converter supplies most of the current, while the linear source supplies the reverse of the ripple current. Two DC-to-DC buck converters have been designed and implemented, giving excellent ripple suppression and high efficiency at very low switching frequencies.<>