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An Improved Current-Doubler with Coupled Inductors
No full text[[abstract]]In this paper, an improved current-doubler rectifier with coupled inductors is proposed, which can extend duty ratio to reduce the peak current through the isolation transformer and to lower output current ripple. Additionally, passive lossless snubbers are introduced to reduce reverse recovery loss and clamp the voltage spike across the rectifier diodes. In this study, a 500W prototype with a full-bridge phase-shift converter, the proposed rectifier, input voltage of 400V and output voltage of 12V was built, from which experimental measurements have shown that the efficiency can reach as high as 92% under full load condition.[[fileno]]2030197030066[[department]]電機工程學
Buck and Boost Derived Converter for Livestock/Poultry Stunning Applications
No full text[[abstract]]This paper proposes a buck and boost derived converter associated with a full-bridge inverter for livestock/poultry stunning applications. The derived converter is formed by combining buck and boost converters to step up or step down input voltage. Compared with the conventional buck-boost converter, the proposed converter can raise efficiency of 4-6% under full load condition. In the paper, mechanism of livestock/poultry stunning is first reviewed and then, the desired stunning voltage waveforms and parameter auto-tuning algorithm are proposed. The output voltage waveforms generated from the converter and inverter are with frequency varying from 50 Hz to 800 Hz, amplitude varying from zero to its breakdown voltage, as high as 250 V, and duty ratio changing from 0.3 to 0.7. Performance measurements from a prototype have verified the parameter auto-tuning algorithm and feasibility of the overall system design.[[fileno]]2030197030074[[department]]電機工程學
A Half-Bridge 1 2W PV Inverter System with Active Power Filtering and Real Power Injection
No full text[[abstract]]This paper presents a half-bridge single-phase two-wire (1 phi 2W) PV inverter system, which can perform both active power filtering (APF) and real power injection (RPI). In the proposed system, it needs only two active switches, reducing cost significantly. In addition, output current of the inverter can be controlled to prevent switches from exceeding their current ratings. Thus, power capacity of the inverter can be effectively used and power quality can be improved. For controlling inverter output current, a current-clamp method (CCM) and an amplitude-modification algorithm (AMA) are proposed, which can determine inverter current command without needs of complicated calculation. Simulations and experimental results have verified the feasibility of the proposed PV inverter system and the two inverter-current control algorithms.[[fileno]]2030197030091[[department]]電機工程學
Analysis and Design of an Active-Clamp Buck Converter with Coupled Inductors
No full text[[abstract]]This paper presents analysis and design of an active clamp buck converter with coupled inductors. The active switch in the converter can sustain a long enough duty cycle while it operates with a high step-down voltage ratio, reducing current stress significantly. In the converter, the active-clamp circuit is used to eliminate voltage spike induced from the leakage inductor of the coupled inductors. Moreover, since both main and auxiliary switches can be turned on with zero voltage switching, switching loss can be reduced and conversion efficiency therefore can be improved significantly. A 120 W prototype of the proposed buck converter was built and experimental results have shown that efficiency can reach as high as 95% (power stage only) and surge can be suppressed effectively. It is relatively feasible for applications to hybrid electric vehicle on-board chargers.[[fileno]]2030197030094[[department]]電機工程學
A PFC Control Circuit for Accommodating Line-Voltage Distortion to Achieve High Power Factor and Low Harmonic Current
No full text[[abstract]]This paper proposes a novel power factor corrector (PFC) controller which mainly includes a sine-wave generator, sample-and-hold circuit and feed-forward gain scheduling circuit. With the sine-wave generator and sample-and-hold circuit, the PFC controller can generate pure sine-wave current command for achieving high power factor and low current distortion even under distorted line voltage or during transient operation. Additionally, with the sample-and-hold circuit, capacitance of the dc-link capacitor can be reduced a lot. Furthermore, the PFC controller with the feed-forward gain scheduling circuit is relatively suitable for universal line-voltage applications. Principle and algorithm of the PFC controller and its unique features are discussed and presented in the paper. A prototype realized with a DSP chip and discrete components has been built, from which simulated and measured results have verified the discussed features.[[fileno]]2030197030095[[department]]電機工程學
High Power Factor Single-Stage ZVS Charger with Coupled Inductors
No full text[[abstract]]This paper presents a zero voltage switching (ZVS) single-stage charger with power factor correction (PFC) based on an asymmetrical half-bridge topology and coupled inductors. The proposed charger is formed from a PFC converter and an asymmetrical half-bridge converter. Coupled inductors are adopted to reduce input current ripple caused by asymmetrical PWM operation, resulting in small input filters. The converter has the features of constant frequency operation, ZVS and low voltage stress imposed on the active switches. Moreover, it can achieve high power factor, high power density, high efficiency, low switching loss and low component count, which make converter operation at medium power levels feasible. In the paper, theoretical analysis and experimental results for a charger with the proposed topology have been obtained, which verify its feasibility.[[fileno]]2030197030127[[department]]電機工程學
