Methods and apparatus for reducing electromagnetic interference (EMI) in power conversion stage line filter are provided herein. The method, for example, includes determining an estimated ripple voltage or estimated ripple current using a predictive model, generating a ripple cancellation signal of opposite polarity to the estimated ripple voltage or ripple current, while compensating for at least one of magnitude or phase distortions in a signal path, and injecting the ripple cancellation signal into a power supply's line filter to reduce a ripple voltage.