| Along with the national basic policy of energy-saving and emission reduction, it has become the direction of market development to upgrade industrial technology and develop environmental protection industry. The advantages of ultraviolet (UV) curing, such as energy-saving, environment-friendly, result in its rapid development. UV curing is a photochemical reaction caused by the curing phenomenon of UV coating in a certain wavelength of UV irradiation. Cured UV coating has the advantages of corrosion preventive, high hardness and fast curing. Compared with the conventional thermal radiation curing, its low-energy curing is especially suitable for heat sensitive material. Therefore, UV curing technology is widely used in aerospace, electronic information, automobile, building materials, furniture and other industries. Excellent UV curing performance needs an electric light source irradiation system with good capacities as its guarantee. Consequently it is very important to study the electronic ballast applied in ultraviolet curing with good performance. At present, the electronic ballast applied to lighting industry is mainly researched, while high-power electronic ballast of UV curing system is not as much as the former. This paper designs an electronic ballast system with good performance of high-power ultraviolet lamp with digital control due to the production demand.This paper introduces the principle and voltage-current characteristic of ultraviolet lamp, expounds the mechanism of UV curing. In the meantime, it studies the relationship between UV irradiation and curing effect. Besides, it summarizes the basic topology of the ultraviolet lamp and the analysis of the starting circuit of electronic ballast for ultraviolet lamp. The work of this paper contains determining the main circuit topology, designing the key parameters of the main circuit, analyzing the principle of operation of coupled inductor and magnetic integration technology. The paper uses back-coupling to reduce the output ripple and improve the dynamic response perfonnance of the system. According to the time-varying characteristics of the negative resistance for ultraviolet lamp from starting to steady state, it introduced the peak current control and the reason of system oscillation in the large duty ratio mode, and designs the slope compensation circuit to restrain oscillation.According to the load characteristics and curing requirements, load UV lamp uses a constant current and constant power control mode and system control strategy is designed. The system employs peak current dual loop control. Considering that analog circuit response is faster than digital circuit, hardware circuits are used for designing peak current control loop. Digital circuits are used in designing and controlling constant current and power and protection. This control mode can effectively improve the system stability and realize the over-current protection. This paper builds the small signal model of the UV curing system and gets the transfer function of the system in order to improve the stability. This paper designs a reasonable compensation based on the Nyquist criterion in the classical control theory methods, makes the compensator discrete by the digital controller. Programming the system software along with flow chart is based on the above work.In the end, a3kW proto of UV curing electronic ballast is produced on the basis of theoretical analysis and calculation in this paper. Besides, debugging and modification of the proto meets the expected targets, so as to verify the feasibility of electronic ballast for ultraviolet lamp. |
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