Quasi state variable method for switching DC-DC converters

For modeling DC-DC power converter circuits, the state space averaging method is the representative method. However, its application field is restricted to small amplitude operation and rather narrow. For large amplitude operation of a DC-DC converter, 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, discrete space state equations can be formulated; all kinds of 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.<>