Considering the multiformity in the PWM modulation principle, the diversity in the structures of filter and load, and the limitation of the method based on state transition matrix in the analysis of digital controlled single-phase full-bridge inverter, we present a new method based on analytic expression of the elements in the state transition matrix. This method can analytically express the relationship between the parameters and the dynamic motion of a system named N-M digitally controlled single-phase full-bridge inverter, which has N state variables and structure changing M times within one switching cycle. As an example, the discriminant of Hopf bifurcation, the analytic expressions of the stability boundary and the oscillation frequency of a 3-3 digitally controlled single-phase full-bridge inverter are derived. Finally, the theoretical results are verified by simulations and circuit experiments.