Júlio César Marques de Lima

Integrated System for Intelligent Street Lighting

This reports the study and hardware implementation of a dimmable electronic ballast for high pressure sodium lamps, and a microprocessor-based system for control and energy measurement for this ballast, which uses a power line communications system to send and receive status and commands from another ballasts plugged in the same mains subcircuit. These ballasts are connected in the topology of a logic network, one of them being defined as the master of the subcircuit, and the others as slaves. The master unit distinguishes from the slaves by the additional communications system, which works through a cell phone, and enables the wireless connection to a PC-based central supervisory system. This way, any locale or town becomes able to control its entire main lighting system, in addition to the obtainment of more accurate data about energy billing, which together with the ability to control luminosity and the better power factor, will result in financial and energetic economy

A PIC controller for grid connected PV system using a FPGA based inverter

The propose of this work is to describe the implementation of a controller for tracking the point of maximum power transfer based on neural networks, using a microcontroller of the PIC family, on energy systems that use photovoltaic panels. A neural network is used to determine, at each instant, the output voltage in a DC-DC boost converter connected to the solar panels, in way to obtain the maximum power transfer of these panels. This implementation releases the use of a great performance computer, once the neural network was already trained and this way, it can be implemented in a dedicated system. The maximum power transfer of the system is obtained adjusting the duty cycle of the DC-DC boost converter. One three-phase inverter was implemented with a new control circuit to generate the PWM signal.

Full Bridge Single Stage Electronic Ballast for a 250 W High Pressure Sodium Lamp

In this paper is reported the study and implementation of a single stage, high power factor (HPF) electronic ballast for high pressure sodium (HPS) lamps using a LCC filter. In the recent years, many authors are working to obtain single stage HPF electronic ballast for fluorescent lamps. Normally, to obtain HPF in electronic ballast for high-pressure sodium lamps, a power factor pre-regulator (PFP) is used between the mains and the electronic ballast. The main idea of this work is to present a simple and low-cost electronic ballast with HPF for HPS lamps, which does not require an additional PFP converter. To get all this advantages the price to be paid is accepting a high crest factor on the lamp

Nonlinear Loads Parameters Estimation and Modeling

This paper describes the study and development of two estimation methods for the values of electrical components concerning the input rectifier present in most of the electronic equipments available in the market. Through these methods, it is possible to identify the values of the EMI filter parasitic inductance, the input filtering capacitance Ccc, and the equivalent load connected to the rectifier. This study will be performed from the analysis of the voltage and current waveforms obtained from an oscilloscope in the input of the equipment under measure. The resulting data will be processed through a mathematical analysis in the time domain. This process will permit the subsequent analysis, modeling and simulation of the complex electrical systems in time domain employing commercial simulators like PSIM, Matlab and ORCAD aiming essentially the study of the influence of these loads over the mains harmonic distortion and power quality.

A PIC controller for grid connected PV system

The propose of this work is to describe the implementation of a controller for tracking the point of maximum power transfer based on neural networks, using a microcontroller of the PIC family, on energy systems that use photovoltaic panels. A neural network is used to determine at each instant the maximum output voltage in a DC-DC converter connected to the solar panels, and so obtain the maximum power transfer of these panels. Once the neural network is trained, it can be implemented in a dedicated system. The maximum power transfer of the system is obtained by adjusting the duty cycle of the DC-DC converter.

Development of a flexible public lighting system

This paper presents the development of a flexible public lighting system which aims to monitor and control electronic ballasts. The system consists of dimmable electronic ballast for high pressure sodium lamps (HPS) with power meter, and a control board with 2.4 GHz digital radios based on the IEEE 802.15.4 (ZigBee) protocol, and data transmission module using SMS. The system has bidirectional communication between the central control and the master units using SMS messaging. Further, the master units send and receive information to and from the slave units via ZigBee modules and coordinates with the central controller the operation of each lamp in their region. This system can measure and report power and energy consumption to a central controller, and to dim, turn on and turn off the lamps individually, controlling the power consumption of the illumination system.

MPPT techniques applied to the control of a module-integrated inverter grid-connected based on Zeta converter for PV panels

This paper presents the study and implementation of maximum power point tracking techniques (MPPT) applied to a module-integrated inverter based on a Zeta converter. The module-integrated inverter allows electricity generated by a PV solar panel to be injected into the commercial power grid. This structure provides significant advantages over the structure that employs the combination of multiple panels connected to a large single inverter (central inverter). Among the advantages offered by the module-integrated structure can be highlighted: modularity, allowing the natural parallelism of the systems, increased system reliability, because in case of failure of a module the plant remains powered after all energy is provided by several PV panels and their module-integrated inverters that work independently, and finally, there is the possibility of obtaining the MPPT individually, which is quite interesting in large systems, where shading may occur in only a few panels. The system employed in this work consists in the association of a PV array to a Zeta converter in cascaded with a single phase full-bridge inverter operating synchronized with the power grid at the same frequency. A Zeta converter working in DCM is responsible for the synthesis of a rectified sinusoidal current waveform synchronized with the grid. The CSI is used to invert the current every 180°. In this study three MPPT techniques were examined, namely Constant Voltage, Perturb and Observe and Hill Climbing. A prototype was built using digital signal processing. The obtained results validated the presented study, described in the work.

A Low Voltage Electronic Ballast Designed For Hybrid Wind-Solar Power Systems

This paper describes the development of an illumination system for open and/or isolated areas like gardens, sidewalks, outdoor lighting for residences and rural areas, demonstration plants on Universities, et cetera. The proposed system is based on a 70 W electronic ballast (EB) for high- pressure sodium (HPS) lamps designed to operate from a low voltage automotive lead-acid battery charged by a hybrid wind- solar power system. A new design criteria for a push-pull EB based on the rated current RMS of the lamp is presented. The paper also includes technical issues faced in building the prototype such as transformer losses generated by skin effect, transformer winding isolation and the effect of high MOSFET drain source current.

Electronic Ballast Design System

In this paper will be reported the implementation of a flexible system to study electronic ballasts. The Electronic Ballast Design System (EBDS) is a microcontrolled and FPGA-based system and was developed to generate command signals to the half bridge inverter. A specific hardware using FPGA was developed to generate the switches signals command. This hardware is responsible for the autonomous frequency generation (in FM mode) and pulse width (PW) both are easily programmed by software, setting free the microcontroller for others applications. This system may be programmed using a personal computer which give us a high level of flexibility, allowing the study of different ballasts topologies, power filters, new control and dimmer techniques, as well as, acoustic resonance effect on high intensity discharge (HID) lamps. Finally, experimental results will be presented for a 250 W electronic ballast for a high-pressure sodium (HPS) lamp, however this system may be used for any kind of discharge lamps.

Simulation tool for conducted EMI and filter design

In this paper a simulation tool that allows us to determine the conducted electromagnetic interference (EMI), generated for the basic PFP (power factor pre-regulator) converters (Cuk, buck, boost, buck-boost, Sepic, and Zeta converters) are presented. Using this software, we can determine full EMI spectrum in dB//spl mu/V in accordance with the CISPR 16 standard. An EMI filter design methodology that allow us to accommodate the conducted electromagnetic interference (EMI) generated by power factor correctors to international standards in the design step is also presented. Therefore, this can be a useful aid for power electronics designers.