Design Of High Frequency Electronic Ballast For 2.5kW HID Lamp

Gas discharge lamp has become the mainstream light source for film and television lighting because of its high light efficiency,high color rendering and continuous spectrum.At the same time,with the increasing demand for high-speed photography,high-speed photography is used to shoot high-speed motion scenes more and more,such as explosive objects,car crashes,etc.,requiring thousands of times per second.With the increasing demand for special lighting,the traditional gas discharge lamp has been difficult to meet the needs of high-speed photography.In order to meet this demand,a new type of high-frequency and high-power gas discharge lamp for film and television came into being.However,the high frequency electronic ballast matching the new lamp is not mature.Current ballasts are confined to structural reasons.Low-frequency ballasts work at low frequencies,resulting in darkness photography;high-frequency ballasts use traditional high-frequency light bulbs with too low power.Therefore,it is necessary to improve the existing ballast to meet the requirements of the new lamp.The bulb used in this project needs to output 125V,25kHz AC voltage.Because the voltage gain curve of LCC resonant inverters is in good agreement with the volt-ampere characteristics of gas discharge lamps,the ballast with LCC resonant inverters as the main circuit is adopted in this project.The main work is divided into the following aspects:(1)In-depth study and analysis of the working principle and light-emitting mechanism of gas discharge lamp,according to the analysis results,and in line with the actual situation,the control method of electronic ballast system matching with gas discharge lamp is studied;(2)Half-bridge LCC resonant inverter circuit is used as the main power supply.The numerical model of resonant circuit is established by using small signal time domain simulation method.In the design of control circuit after that,the non-linear control of ballast start-up stage and constant power control of steady-state stage are realized through the design scheme of piecewise feedback,and the effect of narrowband control is achieved.(3)Start-up of ballast is achieved.Experiments were carried out to verify the consistency between the output characteristics of the system and the start-up characteristics of the gas discharge lamp,and the narrow band control of the ballast was proved.In the design of high-power and high-frequency electronic ballast,PSIM,MATLAB and other software are used to simulate the design,optimize the parameters,get the device parameters of the main circuit and control circuit,and finally make the actual circuit,and verify the designed ballast through experiments.Finally,the matching between the output characteristics of the ballast and the start-up characteristics of the gas discharge lamp is verified by experiments,which lays a foundation for the analysis and improvement of the ballast system.