Stability of digitally controlled PFC boost converter with auxiliary state vector

Power Factor Correction (PFC) converters belong to the variable structure piecewise linear systems due to the switching action. Their complex behaviour is intensively studied. Present paper represents a stability analysis method using the so-called auxiliary state vector to determine the Jacobian matrix of the Poincare Map Function (PMF) to calculate the critical angle where oscillations developes in the inductor current. The effect caused by the Zero-Order Hold, the digital computation delays and the nonideal circuit elements are taken into consideration. The computation delay was approximated by using first and second order Padé approximation. The theoretic results are verified by simulation and the experiment results.