Feasibility study on one cycle control for PWM switched converters

One cycle control (OCC) is a novel nonlinear control method for switched converters and systems. A one cycle controlled switch has the ability to reject the input perturbation and to follow control reference only one switching cycle. But the universal meaning of OCC for switched converters has not been studied yet and so limits its further development and engineering applications. In this paper, the concept and theory of switched linear systems (SLS) were introduced to OCC feasibility study for switched converters. The OCC feasibility for PWM DC-DC converters was studied as examples. At first, basic PWM DC-DC converters were built as periodic switched linear system models. Then according to the characteristics of periodic switched linear system models, the output controllability (OC) concept and its sufficient and necessary criterion in 1-period and m-period of periodic switched linear systems were presented. At last, 1-period OC and m-period OC of buck PWM converter, boost PWM converter and buck/boost PWM converter was analyzed. The analysis results verify that the basic PWM DC-DC converters are output controllable both in 1-period and m-period. It can be seen that OCC can be applied to basic PWM DC-DC converters according to the OC definition in 1-period and m-period. Theoretical analysis result is same as experimental verification of buck PWM converter with OCC in reference K.M. Samdley et al. (1991). The analysis method can be advanced directly to study OCC feasibility for other switched converters or systems.