Modeling Of Resonant Inverter Of The High Frequency Electrodeless Discharge Lamp And Design For Parameters Of The Resonant Tank

The high frequency electrodeless discharge lamp is a kind of new, green light source, and there is no electrode in the bulb that is why it is called high frequency electrodeless discharge lamp. The high frequency electrodeless discharge lamp has many advantages, such as high luminous efficiency, long life cycle, high color rendering, high color temperature. These advantages make the high frequency electrodeless lamp be applied in the road and the public circumstances broadly. Because the working characteristics of the high frequency generator is easily effected by the variation of the temperature and the humidity especially in the rather bad circumstances, it is necessary to make a research on the working characteristics of the high frequency generator. The high frequency generators of the high frequency electrodeless discharge lamp consists of four parts:EMI filter circuit and rectifier circuit, active power factor correction circuit, high frequency resonant inverter. Whether the high frequency inverter and the resonant tank match or not directly effects whether the high frequency electrodeless lamp can be igitated to lighted or not. This thesis mainly makes the research on the modeling of the high frequency resonant inverter and designing the parameters of the resonant tank in order to assure the high frequency electrodeless lamp can work normally all the time avoiding the phenomena of high frequency electrodeless lamp’s hard igitation and arc-blowout.For the high frequency resonant inverter circuit, when the up and down MOSFETs take turn to be on and off, a high frequency square wave is generated. The high frequency square wave which makes the model of the circuit is nonlinear is the input of the resonant tank. Based on the transformer model of the coupler and the bulb, two methods of modeling are put forward to build up the model of the high frequency resonant inverter. The method of state space averaging is broadly applied to build up the power electronic circuit’s model. But there is oscillating current and voltage or alternating currents and voltages in the inverter, the state-space averaging method is not appropriate. The generalized state-space method employs the Fourier series to represent the time evolution of the inverter state variables. The other model is made in the frequency domain. A transfer function for the input and output of the inverter is obtained by the means of averagement in a switch period. And then the transfer function between the lamp’s voltage and the output of the inverter is established. In this way, a model in frequency domain for the high frequency resonant inverter is established. This is a approximate method. The simulation result shows that the model built up by the generalized state-space averaging method is the same as the model establish in the frequency domain. Based on the model established in the frequency domain, the system’s characteristics are analysed including the variation of the lamp voltage, the resonant inductor current, the lamp power with the variation of the parameters of resonant inductor and capacitor. The value range of the resonant inductor and capacitor can be confirmed if the above performance indexes are given. Finally a design with the optimization objective of heat effect transformed from the switching loss is made.The optimization result shows that the designed resonant inductor and capacitor can make the high frequency electrodeless discharge lamp work normally and the heat effect the minimum. The calculated minimal switching loss is more coincidental with the requirement of green light source suggested by the state.