《PIC单片机变频器设计》-毕业论文.docVIP

PAGE w w 摘 要 变频调速技术已经成为节能和提高产品质量的有效措施。变频调速的重要性日益得到国家的重视，在国内推广变频调速技术有着非常重大的现实意义和巨大的经济价值和社会价值。中压变频调速技术是电力电子领域的一个制高点技术，中压大功率变频器是电力电子行业中尚未解决的一个难题。 本论文概述了中压变频器的国内外技术发展及趋势，对中压变频器各种类型的优缺点进行了分析。阐述了单元串联多电平移相式PWM电压源型变频器原理，通过对原理的阐述,进一步透彻的掌握单元串联多电平高压变频器的内部特性 。 研究了单元串联多电平中压变频器的PWM技术和SPWM技术。基于各种PWM 控制技术的对比，本设计选定三角载波移SPWM技术作为控制方法。 文中介绍了IGBT的工作原理和各种保护方法。 给出了基于PIC单片机的五单元串联中压变频器的控制单元的软硬件设计。 关键词：变频器；单元串联中压变频器；PWM技术；移相载波SPWM技术； 单片机 Abstract Velocity adjustmentt echnique of mid-voltage variable frequency is an advanced technique in power electronics realm.mid-voltage and large-power frequency converter is an unsolved difficult in power electronics industry. Its using area basically covers with all kinds of main industry and it has a large market potential. But, compared with latent market, our middle-voltage frequency converter (HVF) is in starting phase in which it is an extremely good opportunity to develop domestic frequency converter manufacturing industry. Velocity adjustment technique of mid-voltage variable frequency has become effective measures to save energy and promote product quality. The expansion of velocity adjustment technique has got very important and realistic meaning and tremendous economic and society value. The progress and the trend of HVF technique，the market requirements domestic and abroad for HVF are reviewed. The advantage and disadvantage of different HVF types, effects of HVF on electric net and electric motor are analyzed in detail. The paper studied the PWM technology and SPWM technology for medium voltagec ascadedm ultilevelin verters. Based on the analysis of kinds of PWM technologies，the design choose the Triangle_Carrier phase-shifted SPWM for cascaded multilevel inverters as control technology. The paper introduced the operation principle and many kinds of protection methods of IGBT. The software and hardware design of control unit of the Five_units Cascaded Medium Voltage Inverter is introduced. Key Words：frequency inverter；Cascaded M