Dynamic modeling and current control of series resonant converters and inverters with non-periodic integral cycle mode

Abstract

In this dissertation, a generalized dynamic modeling, an analysis for the internal characteristics and an improved current control strategy for series resonant converters and inverters (SRC``s and SRI``s) with non-periodic integral cycle mode are newly proposed to overcome the disadvantages of the quantum SRC``s and SRI``s. This kind of power conversion schemes can provide many desirable features due to the zero current switching conditions such as the nearly zero switching loss, smaller filter components, lower electromagnetic interference(EMI) level, etc. Furthermore, the characteristics of the conventional pulse width modulated (PWM) converters such as the buck, boost, and buck-boost converters can also be obtained. However, the quantized output voltage levels and the large current ripple are known as the major disadvantages of quantum SRC``s and SRI``s. Moreover, a large current overshoot appears due to the uncontrollable range in case of a quantum boost SRC and a relatively high peak current level in the steady state is shown in case of a quantum buck-boost SRC. Since the quantized output levels and the large current ripple are mainly caused by the fixed size of integral control cycle, it is basically considered in this dissertation that all kinds of quantum SRC``s and SRI``s should be operated with nonperiodic integral cycle mode. Under this consideration, the degree of freedom for the controller design can be much extended. Firstly, the internal operational characteristics of a quantum buck SRC is analyzed in detail and a new dynamic model for this analysis is also presented. In this analysis, the intermediate current slopes are newly explored and an optimal precictive current control technique is also developed. The advantages of the proposed current control technique are comparatively discussed with the other current control techniques. Using the proposed control technique, the minimized current ripple with reduced offset current and the fast transient...