We have designed various power converters for industrial applications, among them including Buck converters, Boost converters, VRM, Flyback converters, SEPIC, PFC Rectifiers, and Inverters. One essential design problem about these high-efficiency switching power converters is how to eliminate unwanted noise and distortion that arise from switching of power transistors. We have developed several effective feedback modulation and control schemes for this purpose, among them including Feedback Dithering Modulation and Sliding Mode Modulation, which have been proved effective in eliminating noise and distortion in the frequency band of interest.