Research Of The Single-stage Electronic Ballast For HID Lamps With Small Power (70W)

In recent years, small power electronic ballast used more widely, and the single stage electronic ballast became the small power supply the hotspot. This paper puts forward a new circuit topology structure based on using the improved valley-fill circuit.First, this paper introduced the general situation of the electronic ballast and prospect for development, and its basic structure, working principle, and some of the latest technology requirements, etc. Second, enumerated and compared with several common power factor correction technology, analyzes the advantages and disadvantages of various technology, Especially for improved by valley-fill technology PFC details, and also to the harmonic control standard IEC61000-3-2has clearly understand; In addition, also for example this paper introduces and analyses the electronic ballast of the three kinds of topological structure.This paper analyzes the whole process of circuit, and expounds the working principle, the circuit are given in the calculation of the important parameters. Main circuit is passive valley-fill circuit flow by as the foundation, and then will DC-DC and DC-AC merged into one stage, combined with Buck converter and the full bridge DC-AC converters characteristic; Using Orcad16.3software to the circuit simulation, and the simulation results demonstrate the validity of the theoretical analysis.Control system is the continuously the average current control mode of double loops control, namely for inner current loop and the outer power loop, and meet up with the constant power control of the metal halide lamp requirements. Finally, design and build up a electronic ballast prototype for70w metal halide lamp, the experimental results show that the ballast work stable under the condition of the design requirements.The paper mainly includes the finished work of the following sections:(1) the various power factor correction circuits are discussed, and detailed analysis of the improved passive PFC, and improve the power factor, reduce the current harmonic content.(2) Compared to the characteristics of the various topology, and analyzed principle of work for the single stage DC-AC soft switching converter circuit, calculate the realization of ZVS soft switch condition of high frequency switch for half bridge, inductance and capacitance component selection are given in the soft switching network. (3) Establishing equivalent model for single stage soft switch DC/AC main circuit, and gives out the compensation network design of current loop.(4) Gives all kinds of control circuit design,including:the frequency synchronization and complementary PWM signal driven circuit, current, voltage sampling circuit, signal on time-multiplier, benchmark power circuit, current feedback loop and power feedback loop circuit.(5) Main circuit with Pspice software is simulated, given the prototype experiment, and the output waveform analysis, finally summarizes the process of the experiments.