Quasi State Variable Method for Switching DC-DC Converters

Abstract

For modeling DC-DC converter circuits, the state space averaging method is the representative method. However, its application field is restricted to operation of small fluctuation and rather narrow. For operation of large fluctuation, a novel approach which composes the equations by taking the initial values of the circuit at the starting point of each switching period as the state variables is proposed. All instantaneous values of the current and the voltage at each switching period can be represented by a linear combination of these initial values. So, the discrete space state equations can be formulated; all kinds of the information about circuit operation such as average values, waveform envelopes and instantaneous value at an arbitrary instant are given. The solution can be calculated with accuracy as high as one desires, without excessive work