A generalized averaging method is introduced for power conversion circuits, which extends the traditional state-space averaging technique to a broader class of circuits, including resonant converters. The method uses a time-dependent Fourier series representation of a "sliding window" of a waveform to approximate the system's behavior. This approach allows for the analysis of both resonant and pulse-width modulated (PWM) converters by retaining only the significant Fourier coefficients, such as the DC component for fast switching PWM circuits or the fundamental frequency components for resonant converters. The method is shown to be effective in capturing the dynamics of these systems, even when the "small ripple" assumption does not hold. It is demonstrated that the method can be applied to both steady-state and transient analyses, and it provides a framework for control design. The method is validated through examples, including a series resonant converter with voltage and capacitor loads, and a PWM up-down converter. The results show that the generalized averaging method provides accurate approximations of the system behavior and can be used for both simulation and design purposes. The method is also applicable to systems with time-varying frequencies, where the analysis is adjusted to account for the changing drive frequency. The approach is shown to be more accurate than traditional state-space averaging, especially in cases where the ripple is not small. The method is particularly useful for analyzing and controlling power electronic circuits where the "small ripple" condition does not hold.A generalized averaging method is introduced for power conversion circuits, which extends the traditional state-space averaging technique to a broader class of circuits, including resonant converters. The method uses a time-dependent Fourier series representation of a "sliding window" of a waveform to approximate the system's behavior. This approach allows for the analysis of both resonant and pulse-width modulated (PWM) converters by retaining only the significant Fourier coefficients, such as the DC component for fast switching PWM circuits or the fundamental frequency components for resonant converters. The method is shown to be effective in capturing the dynamics of these systems, even when the "small ripple" assumption does not hold. It is demonstrated that the method can be applied to both steady-state and transient analyses, and it provides a framework for control design. The method is validated through examples, including a series resonant converter with voltage and capacitor loads, and a PWM up-down converter. The results show that the generalized averaging method provides accurate approximations of the system behavior and can be used for both simulation and design purposes. The method is also applicable to systems with time-varying frequencies, where the analysis is adjusted to account for the changing drive frequency. The approach is shown to be more accurate than traditional state-space averaging, especially in cases where the ripple is not small. The method is particularly useful for analyzing and controlling power electronic circuits where the "small ripple" condition does not hold.