Domingos Sávio Lyrio Simonetti

High power factor electronic ballast operating at critical conduction mode

A high power factor electronic ballast, that exhibits low switching losses is presented in this paper. The proposed topology is based on a single power processing stage which provides high frequency voltage to the fluorescent lamps and high power factor to the utility line. The lamps are driven by a self-oscillating half-bridge series resonant converter of great simplicity and attendant low cost and increased reliability. High power factor is achieved by using a nonconventional boost converter operating at critical conduction mode. Theoretical analysis and experimental results for two 40 W fluorescent lamps operating at 50 kHz from 127 V utility line have been obtained, which demonstrate the high efficiency and high power factor of this electronic ballast.

HID Lamp Electronic Ballast With Reduced Component Number

A reduced-component-number single-stage power-processing electronic ballast to drive high-intensity discharge lamps is presented in this paper. A dc-dc buck converter, which controls the current and the power of the lamp, a power factor preregulator based on a discontinuous conduction mode boost converter, and the inverter are combined in a boost integrated with buck rectifier/energy storage/dc-dc converter. It operates with a line-frequency square-wave current driving the lamp. The signals of the power stages are provided by a dedicated microcontroller. Ballast for sodium vapor lamps of 70 W without acoustic resonance was implemented, resulting in a pf = 0.97 with 22% total harmonic distortion and eta = 84%.

Improving the operation of ZVT DC-DC converters

This paper presents an improved ZVT DC-DC boost power converter using a regenerative snubber. The proposed snubber uses a magnetically coupled cell to reduce the turn-off switching loss of the auxiliary switch. The method has been employed to build a 500 W/100 kHz prototype. The experimental results show the ZVT DC-DC boost converter waveforms with and without the regenerative snubber. A high efficiency is achieved using the proposed improvement.

Microcontrolled electronic gear for low wattage metal halide (MH) and high-pressure sodium (HPS) lamps

This paper presents an electronic control gear for HID lamps that operates with a low frequency current inverter to drive the lamp, a DC-DC buck converter to control the current and the power of the lamp and a power factor pre-regulator based on discontinuous conduction mode boost converter. All signals of the power stages are provided by a dedicated microcontroller. An overview of the lamp operation phases and the strategies to avoid acoustic resonance are mentioned. A 70 W prototype without acoustic resonance and stroboscope effect was implemented. The approach can be easily extended for other rated power.

Single stage self-oscillating HPF electronic ballast

This paper presents a single-stage self-oscillating high-power-factor electronic ballast more suitable for both low power levels (because it operates in discontinuous conduction mode) and low ac mains applications (since it employs an input-doubler rectifier). The electronic ballast is based on a high-frequency dither signal, which shapes the input current in a sinusoidal waveform. In order to reduce the electronic ballast components the self-oscillation technique has been employed. An electronic ballast prototype operating at 25 kHz has been implemented to drive two 40-W straight-type fluorescent lamps from a 127-V utility line. High power factor is achieved even though the electronic ballast drives just one fluorescent lamp. The experimental results demonstrated the electronic ballast operation.

A magnetically coupled regenerative turn-on and turn-off snubber configuration

This paper presents a magnetically coupled regenerative turn-on and turn-off snubber configuration applied to a boost converter, which operates in continuous conduction mode (CCM). In addition to reducing the stresses in the switch, providing soft transitions in its turn-off voltage and turn-on current, it transfers the energy stored in the snubber capacitor to the load. This is achieved by using a coupled inductor mounted on the main inductor of the converter, which resets the capacitor voltage at each switching period. Design equations, as well as experimental results are presented, showing the high performance of the boost converter using the proposed snubber.

An isolated DC-DC boost converter using two cascade control loops

This paper presents an isolated DC-DC power converter designed to operate as the primary stage of an on-board DC-AC power supply for diesel-electric engines. The DC-AC power supply must provide a sinusoidal waveform of 127 V RMS from the 72 V DC bus of the engine. The DC-DC push-pull current-fed power converter has been used to obtain an isolated 200 V DC output voltage from the available 72 V DC bus engine. This power converter operates as a boost converter with constant frequency and duty cycle greater than 50%. Two control loops operating in cascade mode were used. A fast inner current loop regulates the boost inductor current, whereas an external control loop keeps a constant output voltage. Experimental results have been obtained for a 300 W laboratory prototype operating at 50 kHz. The power converter efficiency was 93% at full load, and the output voltage regulation was less than 1% for 10% to 100% load changes.

Converter topologies for permanent magnetic synchronous generator on wind energy conversion system

This paper presents a review of wind energy conversion topologies applicable to permanent magnetic synchronous generator. The use of wind energy as a promissing renewable energy in actual world conjuncture and its use on distributed generation is summarized; a comparison between the main generators used in wind energy production related to the advantages of each one is shown. The paper mainly discusses converter topologies in use with permanent magnetic synchronous generator, focusing on the advantages and control techniques applied.

A review of the main inverter topologies applied on the integration of renewable energy resources to the grid

This paper describes the main inverter topologies intended to connect the renewable energy resources to the grid utility. It shows the circuit configuration of the fullbridge three-phase inverter, flyback inverter, Z-Source inverter and neutral point clamped inverter, and it also discusses their advantages and disadvantages for each application. At last, a list of non-common topologies that handle specific issues of renewable resources is presented.

A DCM three-phase SEPIC converter for low-power PMSG

A new three-phase controlled converter for low-power PMSG is presented in this digest. The converter is a SEPIC one, operating at DCM. The topology incorporates the PMSG inductance as its input inductor, and the generator currents are almost harmonics-free. Design equations are also presented, and results from simulations for both high and low wind speed show that this topology has a strong potential in the proposed application.