Ting-Peng Lee

Grid-Connected Photovoltaic System With Power Factor Correction

A combined grid-connection/power-factor-correction technique for a photovoltaic (PV) system is proposed in this letter. A maximum power point tracking dc/dc converter served as a charger for the battery bank. A bidirectional inverter is applied as a generator/discharger during daytime, supplying power to the load. The inverter can also be used as a charger to maintain the minimum required voltage level of the batteries when the PV power is insufficient. Experiments on a 1-kW PV system show satisfactory results of the power management and the unity power factor at the utility side.

Design of an RGB LED Backlight Circuit for Liquid Crystal Display Panels

This paper presents a red, green, and blue (RGB) light-emitting diode (LED) backlight circuit for liquid crystal display (LCD) panels. Some studies have been conducted to devise dimming methods that regulate the RGB LED currents. In this paper, design considerations for the RGB LED backlight are presented. A laboratory prototype for 20-in panels is implemented and tested. The color gamut of an LCD panel with the designed RGB LED backlight is measured and discussed. The experimental results of the laboratory prototype are also shown to verify feasibility of the findings.

Analysis and Design of a Photovoltaic System DC Connected to the Utility With a Power Factor Corrector

This paper presents a photovoltaic (PV) system parallel connected to an electric power grid with a power factor corrector (PFC) for supplying the DC loads. The operation principles and design considerations for the presented PV system are analyzed and discussed. The balanced distribution of the power flows between the utility and the PV panels is achieved automatically by regulating the output DC voltage of the PFC. Experimental results are shown to verify the feasibility of the proposed topology, which can effectively transfer the tracked maximum power from the PV system to the DC load, while the unity power factor is obtained at the utility side.

A DSP-based single-stage maximum power point tracking PV inverter

This paper presents the design and implementation of a DSP-based single-stage photovoltaic (PV) inverter system which can extract maximum power from solar panel. A perturbation and observation (P&O) method is realized and cooperated with a digital unipolar voltage switching sinusoidal pulse width modulation. The studied single-stage topology provides the benefits of low cost, simple configuration and good overall efficiency compared with the conventional two-stage structure. Moreover, this paper also presents a new current sensing technique for maximum power point tracking (MPPT) to enhance the system flexibility and MPPT accuracy. A prototype system is implemented and tested. The experimental results are shown to verify the feasibility of the proposed scheme.

A Modular Self-Controlled Photovoltaic Charger With InterIntegrated Circuit (

This paper presents a modular self-controlled photovoltaic (PV) charger with maximum power point tracking (MPPT) and pulse-charging schemes. The studied PV modules can be flexibly parallel connected through interleaved operation using an interintegrated circuit (I2C) interface. The MPPT control of PV panel is implemented by using a current-sensing technique with the on-state resistance of the power switch. Both an expensive hall-effect sensor and additional current-sensing resistor are not needed. A pulse-charging scheme without extra battery-current sensor is also designed to prolong the lifetime of the acid-lead battery. The operation principles and design considerations of the proposed PV charger are analyzed and discussed. A laboratory prototype is implemented and tested to verify its feasibility.

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Abstract- Energy-retaining snubbers of a current-regulated power supply for an AC arc welding machine are proposed in this paper. Although a second output inductor is added, a current- steering diode connected across the output choke keeps the inductor current continuous and retains the energy during the commutation period. Thus no lossy RC snubber is required and no voltage spike is produced. The stored energy can be released in the next energy transfer cycle to reduce the commutation time. Satisfactory experimental results on a 100-A AC arc welding machine are recorded to validate the effectiveness of the presented scheme.

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A battery charger with MPPT function for low-power PV system applications is presented in this study. For effective miniaturization, the battery charger is designed with high frequency operation. Some current-sensing techniques are studied, and their MPPT implementation is compared. A pulse charging method is also designed to prolong battery lifetime. The operation principles and design considerations of the proposed PV charger are analyzed and discussed in detail. A laboratory prototype is implemented and tested to verify the feasibility of the proposed scheme. Experimental results show that high MPPT accuracy and conversion efficiency can be simultaneously achieved under high frequency operation.