Estudo de modelos para lâmpada de vapor sódio de alta pressão com injeção de terceira harmônica aplicado ao controle de corrente

• Ano de defesa: 2013
• Autor(a) principal: Tiago de Sa Ferreira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Injeção de harmônicas; Modelagem; Controle; Ressonância acústica; Lâmpadas HPS; Engenharia elétrica; Modelos e construção de modelos; Iluminação
• Link de acesso: http://hdl.handle.net/1843/BUBD-ADCFPZ

High pressure sodium lamps are a type of high intensity discharge lamp. Its qualities make them adequate to be used in external and industrial lighting systems. However, such lamps are complex devices, mostly due to their negative incremental impedance behavior. Thus, highly faithful models of these devices have a large number of variables and parameters to be determined. In this work, a comparative study of a 70W high pressure sodium lamp time domain models is presented. Four equivalent circuits of different obtainability and building complexitieshave their performance compared for operation with third harmonic injection in order to avoid the acoustic resonance phenomenon. This models are the lamp as a pure linear resistance, an empiric model constituted by an equation derived of a set of RMS current and voltage measurements for several output power values (Ferrero), one based on the idea that a discharge column in the gas behaves approximately as a negative temperature coefficient resistor (Mader-Horn) and one based in the system energy balance equations while including in its formulation the dynamic electrode voltage drop and the hysteresis effects of the V-I characteristics of the lamp (Yan). To validate and characterize these models, experimental data of the lamp operating in steady state with and without harmonic injection is used. The electronic ballast used to gather experimental lamp current and voltage data consists of numerous elements. The input filter act to correct the network current distortion, suppress radio frequency interference and remove feeding spikes. The rectifier, combined with the capacitive filter, converts the alternated feeding voltage into a continuous voltage. The resonant inverter converts the continuous voltage into a high frequency voltage and enables the lamp ignition, also eliminating the low frequency strobe effect and flicker. A boost converter is inserted as an intermediate stage between the rectifier and the resonant inverter to allow power factor correction. The modulation index control, performed with the help of a microprocessor,allows the use of a small step-up inductor (the equipment ends up smaller and lighter). After being duly scrutinized, the model considered to have shown best performance considering the lamp behavior in both low and high frequencies was the Yan model. From this equivalent circuit, a frequency domain lamp model is found. In turn, from this final transferfunction, a lamp circulating steady state current control strategy is proposed composed by a power control loop to provide current reference and a current control loop. The closed loop system is, therefore, simulated with different operation points to ascertain its performance andverify the effective desired current control. A voltage control strategy during the lamp warmup phase is also proposed.