【作者】 周庆忠；

【导师】 贲洪奇；

【作者基本信息】 哈尔滨工业大学 ， 电力电子与电力传动， 2008， 硕士

【摘要】 微弧氧化工艺具有处理效率高,对环境污染小等优点,具有巨大的推广潜力和应用前景。本文基于微弧氧化工艺研究的需要,研制一种输出波形为正负半波幅值不对称、存在可调节过零死区,并且可在一定范围内连续调频调幅的不对称正弦波逆变电源。该电源采用两级拓扑结构,前级为直流调节部分,后级为不对称正弦波逆变部分。为减少损耗、提高效率,前级直流调节部分采用变压器原边串联阻断电容和饱和电感的全桥ZVZCS拓扑结构,借助变压器漏感和输出滤波电感储能,可使超前臂IGBT在很宽的负载范围内实现ZVS;利用阻断电容电压强迫变压器原边电流迅速复位,使滞后臂IGBT可以在整个负载范围内实现ZCS。通过对全桥电路模态分析,可知前级直流调节电路的最大占空比有一定限制,为稳定电压输出和扩大占空比范围,设计了斜坡补偿电路。后级不对称正弦波逆变部分,主电路采用全桥拓扑结构,控制策略采用HPWM控制方式;根据控制电路的功能分别设计了基准波发生电路、精密整流电路、正负半波幅值检测电路、UC3637控制芯片外围电路等控制电路。通过对过零死区不对称正弦波进行傅立叶级数分析,设计了滤波环节。在不对称正弦波逆变电路的实验基础上,结合仿真分析对输出电压波形在过零点处的失真现象进行了研究。引起输出波形过零失真的原因主要是:调制波的抬升电压、死区时间以及电感电流续流。针对上述原因,采取了抑制措施。实验结果表明,可以抑制输出波形的过零失真,也有助于优化输出波形。为验证上述理论分析的正确性,结合电路仿真,设计了小功率实验逆变电源,并完成了相应的调试。实验结果表明,不对称正弦波逆变电源达到了预定的设计要求。更多还原

【Abstract】 The technique of Micro-plasma oxidation has several merits: high efficiency and little pollution, it has promotion patent and broad applied foreground. To meet the need of the research of Micro-plasma oxidation an asymmetric sinusoidal inverter is needed to be developed, it amplitudes between the positive period and the negative are different, its dead-time of zero passage is adjustable, and its amplitude and frequency can be regulated continuously in some range. The two-stage topology is adopted in asymmetric sinusoidal inverter, the backing stage is a high voltage DC power; the latter is an asymmetric sinusoidal inverter. Considering the loss and efficiency of the inverter system, the backing stage of asymmetric sinusoidal inverter adopts FB-ZVZCS converter topology. With the help of transformer leakage and filtering inductor, ZVS of leading-leg switches is realized in wide range of load. The voltage of blocking capacitor is added to leakage of transformer and the primary current is reset, and then ZCS of lagging-leg switches is realized in whole range of load. By analyzing modes of converter, we could know that maximum duty cycle is restricted. The slope compensation circuit is designed, to stabilize the output of the backing stage part and extend the duty cycle range.For the latter stage of asymmetric sinusoidal inverter with adjustable dead-time of zero passage, the main circuit of inverter adopts full bridge topology and HPWM. UC3637 is selected as core chip to control the circuit, and other functional circuits are designed such as: the reference generator of asymmetric sinusoidal waveform, the circuit of precision rectifier circuit, and the circuit of peak detector. According to the analysis of Fourier’s series to asymmetric sinusoidal waveform with adjustable dead-time of zero passage, the filter link is designed.On the base of the experiments of the inverter, causes are studied which result in the distortion of zero passage composed of simulation. The causes are uplift of modulation waveform、dead-time and inductor continuous flow , and the measures are presented. The experiment shows measures work, and help to restrain the distortion of zero passage. In order to validate the exactness of the analysis and theory, on the base of simulation, a small power experimental inverter has been designed and debugged, The experimental results indicate that this inverter meet all design targets well.更多还原