|PER-1||Rotating Switching Surface Control
of Series-Resonant Converter Based
on a Piecewise Affine Model
|In this paper, the control signal of the series-resonant converter is considered as a slope of a switching surface. The output
Characteristic of the converter, for an ideal case and above the resonant frequency, is achieved based on the slope of the switching surface. This output haracteristic leads us to find the related slope for a specific converter gain. Nonlinear state equations of the series-resonant converter with new control input are represented in
widely used class of hybrid systems that have been called piecewise affine systems. Considering the effects of the slope variations in the switching surface, a simple and efficient control law is achieved. The main advantage of the proposed method is the absence of microcontroller and frequency modulator integrated circuits in hardware implementation. This property makes the proposed method more beneficial in high-frequency applications. Experimental results confirm our theoretical investigations.
|PER-2||Analysis and Design of LLC Resonant Converters With Capacitor–Diode Clamp Current Limiting||This paper presents a design methodology for LLC resonant converters with capacitor–diode clamp for current limiting in overload conditions. A new fundamental harmonic
Approximation-based equivalent circuit model is obtained through the application of describing function techniques, by examining the fundamental behavior of the capacitor–diode clamp. An iterative
Procedure to determine the conduction point of the diode clamp is also given. The behavior of this type of converter is analyzed and guidelines for designing the current limiting characteristics are discussed. The characterization of a 90 W converter design using the proposed methodology is presented. The converter voltage gain and the voltage–current characteristics under different overload conditions and operating frequencies are predicted using the proposed model, which accuracies are validated against the prototype with good correlation.
|PER-3||A Bidirectional LLC Resonant Converter With Automatic Forward and Backward Mode Transition||This paper proposes an improved bidirectional LLC resonant topology with a new control scheme. All the switches
in the proposed topology can achieve soft switching. Compared with traditional isolated bidirectional dc–dc converters such as dual active bridge converter, the reverse energy and turn-off loss are reduced dramatically, and the conversion efficiency can be much improved. With the proposed new control scheme, the power flow direction and output power of the proposed converter can be changed automatically and continuously, which is attractive for energy storage systems to balance the energy and to keep the dc-bus
Voltage constant. Performance of the proposed circuit is validated by the experimental results from a 1-kW prototype. Over 97% efficiency is achieved at full load condition based on the prototype.