Browsing by Author "Li, Heng-Yi"

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A single stage single switch parallel AC/DC converter based on two output boost-flyback converter
(2006)
Li, Heng-Yi
;
Chang, Lon-Kou
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A single-stage-single-switch (S4) parallel ac-to-dc converter based on single-switch-two-output (SSTO) boost-flyback converter is presented. This converter remarkably improves the power processing performance. The converter contains two semi-stages. One is the boost-flyback semi-stage that has excellent self-PFC property when operating in DCM even though the boost output is close to the peak value of the line voltage. Moreover, it allows part input power transferred to load directly through the flyback path so the power conversion efficiency is improved. The other one is the forward semi-stage that provides another parallel power flow path and improves the regulation speed. Furthermore, the bulk capacitor voltage is low due to only partial power is processed through it. Hence, the proposed converter is suitable for universal input usage.
Analysis and Design of a Single-Stage Parallel AC-to-DC Converter
(2009-12-01)
Li, Heng-Yi
;
Chen, Hung-Chi
;
Chang, Lon-Kou
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, a single-stage (S(2)) parallel ac-to-dc converter based on single-switch two-output boost-flyback converter is presented. The converter contains two semistages. One is the boost flyback semistage, which transfers partial input power transferred to load directly through one power flow path and has excellent self-power factor correction property when operating in discontinuous conduction mode even though the boost output is close to the peak value of the line voltage. The other one is the flyback dc-to-dc (dc/dc) semistage that provides the output regulation on another parallel power flow path. With this design, the power conversion efficiency is improved and the current stress of control switch is reduced. Furthermore, the calculation process of power distribution and bulk capacitor voltage, design equations, and design procedure for key parameters are also presented. By following the procedure, an 80 W prototype converter has been built and tested. The experimental results show that the measured line harmonic current at the worst condition complies with the IEC61000-3-2 class D limits, the maximum bulk capacitor voltage is about 415.4 V, and the maximum efficiency is about 85.8%. Hence, the proposed S(2) converter is suitable for universal input usage.
Dynamic Modeling and Controller Design for a Single-Stage Single-Switch Parallel Boost-Flyback-Flyback Converter
(2012-02-01)
Li, Heng-Yi
;
Chen, Hung-Chi
;
電子物理學系
;
Department of Electrophysics
In general, partial power of the parallel ac/dc converter is processed only once and transferred directly. In order to keep the output voltage constant, the switching duty ratio in the parallel converter must vary with the line phase. It means that the operating point of the parallel ac/dc converter changes with the variation of input voltage, which would be a challenge for controller design. In this paper, the dynamic modeling of a single-stage single-switch parallel boost-flyback-flyback converter is developed by the linearization of its large-signal equations. To overcome the modeling uncertainty due to the variation of operating point, the feedback controller is designed based on the boundary of the mode to obtain zero steady-state error, fast rise time, and heavily damping within input voltage range. Both the derived dynamic modeling and the designed voltage controller are demonstrated by the provided simulation and experiment results.
Dynamic Modeling and Controller Design for a Single-Stage Single-Switch Parallel Boost-Flyback-Flyback Converter
(2012-02-01)
Li, Heng-Yi
;
Chen, Hung-Chi
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In general, partial power of the parallel ac/dc converter is processed only once and transferred directly. In order to keep the output voltage constant, the switching duty ratio in the parallel converter must vary with the line phase. It means that the operating point of the parallel ac/dc converter changes with the variation of input voltage, which would be a challenge for controller design. In this paper, the dynamic modeling of a single-stage single-switch parallel boost-flyback-flyback converter is developed by the linearization of its large-signal equations. To overcome the modeling uncertainty due to the variation of operating point, the feedback controller is designed based on the boundary of the mode to obtain zero steady-state error, fast rise time, and heavily damping within input voltage range. Both the derived dynamic modeling and the designed voltage controller are demonstrated by the provided simulation and experiment results.
Phase Feedforward Control for Single-Phase Boost-Type SMR
(2009-05-01)
Chen, Hung-Chi
;
Li, Heng-Yi
;
Yang, Ru-Shiuan
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this letter, a phase feedforward control (PFFC) for a single-phase boost-type switching-mode rectifier is addressed. In the conventional input voltage feedforward loop, the feedforward signal is fixed regardless of the load level. The proposed phase feedforward signal adjusts according to the load level without sensing the load current. The simulated and experimental results also demonstrate the effectiveness of proposed PFFC. Compared to a conventional feedforward signal, relatively small proportional gain can be used in the proposed PFFC without loss of current tracking performance, which would also increase the overall system immunity against noise.