Author_Institution :
Dept. of Electr. Eng., Virginia Polytech. Inst. & State Univ., Blacksburg, VA, USA
Abstract :
For pt.I see ibid., vol.26, no.3, p.490-6 (1990). According to the method of state-space averaging, when a pulsewidth modulation (PWM) converter enters discontinuous conduction mode (DCM), the inductor current state is lost from the average model of the converter. It is shown that there is neither theoretical nor experimental justification for the disappearance of the inductor state as claimed by the method of state-space averaging. For example, when the model of the PWM switch in DCM is substituted in the buck, boost, or buck-boost converter while the inductor is left intact, the average model has two poles: the first pole fp1 agrees with the single pole of state-space averaging, while the second pole fp2 occurs in the range fp2⩾Fs/π. It is shown that the right-half plane zeros present in the control-to-output transfer functions of the boost, buck-boost, and Cuk converters in continuous conduction mode are also present in discontinuous conduction mode
Keywords :
network analysis; power convertors; pulse width modulation; switching circuits; Cuk converters; PWM converters; PWM switch; average model; buck-boost converter; control-to-output transfer functions; discontinuous conduction mode; inductor current state; right-half plane zeros; state-space averaging; Inductors; Power supplies; Predictive models; Pulse width modulation; Pulse width modulation converters; Switches; Switching converters; Switching frequency; Transfer functions; Transient response;
