Itsda Boonyaroonate

Single-stage electronic ballast with class-E rectifier as power-factor corrector

A single-stage high-power-factor electronic ballast with a Class-E rectifier as a power-factor corrector is proposed. A Class-E rectifier is inserted between the front-end bridge rectifier and the bulk filter capacitor to increase the conduction angle of the bridge-rectifier diode current for obtaining low line-current harmonics. The Class-E rectifier is driven by a high-frequency sinusoidal current source, which is obtained from the square-wave output voltage of the Class-D inverter through an LC series resonant circuit. A high-frequency transformer is used for impedance matching. The experimental results for a 32-W prototype ballast are given. The switching frequency was 61.3 kHz. At full power, the power factor was 0.992 and the total ballast efficiency was 88.3%. The lamp-current crest factor was about 1.36. The simulated and experimental results were in very good agreement.

Single-Stage Electronic Ballast Using Class-DE Low-

A single-stage high-power-factor electronic ballast with a Class-DE low-dv/dt rectifier as a power-factor corrector is proposed in this paper. The power-factor corrector is achieved by using a bridge rectifier that acts as the Class-DE low-dv/dt rectifier. The Class-DE low-dv/dt rectifier is driven by a high-frequency current source, which is obtained from the square-wave output voltage of the Class-D parallel resonant inverter through an LC -series circuit. By using this topology, the conduction angle of the bridge rectifier diode current is increased, and a low line-current harmonic is obtained. A prototype ballast is implemented to drive a 36-W fluorescent lamp. The switching frequency is fixed at about 84 kHz. Experimental results verify the theoretical analysis. The designed electronic ballast has a power factor of 0.99, a total harmonic distortion of 1.3%, a lamp current crest factor of 1.42, and 90% efficiency at full power.

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A class E isolated DC/DC power converter for regulating the output voltage at a fixed switching frequency is presented, analyzed and experimentally verified. It consists of class E series-resonant inverter, high-frequency transformer and class E low dv/dt pulse width modulation (PWM) synchronous rectifier. By controlling the conduction time of the controlled switch in the rectifier, high-frequency AC current is rectified and the output voltage can be controlled at the same time. The zero voltage switching (ZVS) condition of all switches can be maintained from full-loaded to open-loaded. The theoretical predictions were in good agreement with the experimental measurements and the maximum efficiency measured at a switching frequency of 1 MHz was 91.2%.

Current-Source-Driven Rectifier for Power-Factor Correction

The low stress voltage balance charging circuit for series connected batteries based on buck-boost topology is present and experimented. In the proposed circuit, the number of circuit components and the switches stress voltage are lower than the conventional system. By connecting the proposed circuit and applying the proposed control algorithm with the series battery pack, the unbalance charging problem which usually occurred in the series connected charging system can be eliminated.

Analysis and design of class E isolated DC/DC converter using class E low dv/dt PWM synchronous rectifier

Class E isolated DC-DC converters regulating the output voltage at fixed switching frequency are presented and experimental results given. They consist of class E series resonant inverter, high-frequency transformer and the controllable class E low dv/dt synchronous rectifier. By controlling the conduction time of a controlled switch in rectifier, high-frequency ac current will be rectified and the output voltage can be controlled or regulated in the same time. By parallel connection of the rectifiers at each secondary coil of transformer and applying the PWM control to each rectifier, the circuits supplies and regulates the multiple output voltages at a fixed switching frequency and maintains the ZVS condition of all switches from full-load to open-load.

The low stress voltage balance charging circuit for series connected batteries based on buck-boost topology

This paper present the study of photovoltaic cell (PV Cells) output power characteristics by experimenting with the simulation of equivalent circuit and of output behavior of photovoltaic while connected to the buck converter, with adjustment of its duty ratio (D). Experimental result show that the maximum power point (MPP) is reduced 24 %, while connected to the buck converter load compared with the linear load (resistor). The simulation results from MATLAB / Simulink program have a good agreement with the experimental.

Class E isolated DC-DC converter using PWM synchronous rectifier

A compact DC/AC inverter for automotive applications is presented and experimented upon. The proposed inverter consists of a full bridge inverter and a new ZVCS quasi-resonant push pull DC/DC converter. The new DC/DC converter converts input 12 V (from battery) to high voltage (about) 200V at very high conversion efficiency without regulation. The high voltage will be converted to AC at the desired voltage and frequency by the full bridge inverter. The experimental results show the new unregulated push-pull DC/DC converter can be applied to automotive inverters to reduce the size and increase the conversion efficiency.

Simulation and study of photovoltaic cell power output characteristics with buck converter load

A new application of power source element in power factor correction is proposed. The power source is inserted between the bridge rectifier diodes and a large bulk capacitor to increase the conduction angle of the rectifier diodes. The power from the DC bus is transferred to power the source via a loss free resistor connected with the DC bus. Analysis, design example, control scheme, and simulation results are given in this paper.

A compact DC/AC inverter for automotive application

A compact DC/AC inverter for a large electroluminescent (EL) lamp is presented and experimentally studied. The inverter topology based on the push-pull inverter, and its operations are similar to that of the flyback converter. The DC input voltage is converted to a high frequency AC voltage by the push-pull inverter at a switching frequency of 50 kHz and then rectified to AC 200 Vp-p/500 Hz by the bi-directional synchronous switch. By using this technique, HVDC capacitor, high side switch gate-drive transformers and rectifier diodes are not required. The measured efficiency when the inverter was loaded by 193.34 inch/sup 2/ EL lamp is about 78% at an output power 4.8 W.

Application of Power Source Element in Power Factor Correction

Low-power dichroic halogen lamps, usually used for display lighting, have low-voltage filaments. The lightweight electronic transformer (ET), based on self-oscillating half-bridge high frequency inverters, are used to replace bulky and heavy conventional 50/60 Hz step-down transformers. However, their lamp currents are rectangular-like in shape, leading to generation of high electromagnetic noise and increased transformer core losses. This paper proposes a new, near sine lamp current, electronic transformer using class-D zero-voltage-switching (ZVS) inverter. The experimental results from a 50 W/12 V prototype show that efficiency is greater than 92% with unity power factor. Moreover, the dimmable feature and controlled starting current can be achieved by simply increasing the switching frequency without increasing the switching loss.