高压大容量H桥串联型变频器的研究

【作者】 孙洪斌；

【导师】 陈宜通；

【作者基本信息】 西安建筑科技大学 ， 机械工程， 2004， 硕士

【摘要】 我国是能源生产和消费的大国，但是长期以来一直都存在着严重的能源浪费的问题。据统计，我国风机、水泵年耗电量占全国发电量的约40％。理论分析和实际应用都表明，如果采用调速技术，至少可节约20％以上的电能，有些情况下甚至可节电70％。本文以太钢某厂额定功率2240KW，额定电压6300V注水泵电机变频调速科研工程为背景，从理论分析、计算机仿真和装置实验几方面入手，对高电压大容量串联H桥多电平变频器的理论和工程应用技术进行较深入研究。 串联H桥多电平变频器的主回路从结构上可分为三相电容滤波不可控整流电路和单相电压型全桥逆变电路。对于整流电路，由于采用变压器移相多重化整流，在理论上可以实现曲折变压器一次绕组中低于6M±1次谐波电流相互抵消(M为串联单元个数)；对于逆变电路，由于采用移相PWM控制方式，等效开关频率提高M倍，因此输出电压接近正弦波，谐波含量较小。 串联H桥多电平变频器具有输出电压高、功率大，输入侧和输出侧谐波含量小，输入功率因数高等特点。另外，采用模块化设计，易于提高电压、处理故障，维护也比较简单。还有，变频器对电机无特殊要求，适于普通电机，有利于旧系统改造。 本文综述了高电压大容量变频器技术的发展现状，给出了串联H桥多电平变频器的主回路的拓扑结构和工作原理。重点分析了变压器曲折接法和移相多重化整流对网侧谐波的影响及移相PWM控制方式对减少输出侧谐波的作用，并给出理论计算结果和计算机仿真波形。本文最后给出了系统的工程设计参数和实验波形。从实验结果来看，实际结果与理论分析是一致的。目前该装置已在太钢试运行。更多还原

【Abstract】 The energy source production and consumption are huge in China, but the situation of wasting energy source is a serious issue for a long time. According to the statistical data, in China only the power consumption of fans and pumps take the 40% of annual electric power production. It has been proved by theory and practice that variable speed motor drive can at least save electric power more than 20%, even to 70% in some situations. The background of this dissertation is based on a project of researching and developing a high voltage series H-bridge multilevel converter, which drives an induction motor of 6300V, 2240kW for driving a water flooding pump in Taigang. The research work on high voltage high power series H-bridge multilevel converter has been carried out by theory analysis, computer simulation and experiments.The series H-bridge multilevel converter’s power circuit is composed of uncontrolled rectifier with filtering capacitor and single phase H-bridge voltage-type inverter. As a result of employing multilevel phase-shifted method with zig zag connection in transformer secondary, in the primary the current harmonics their orders are lower than 6M 1 are eliminated (M is the number of power cell each phase). In the inverter side because of using pulse shifting PWM control, the equivalent switch frequency of output is M times as high as one H-bridge, so the output voltage waveform of the inverter is near sine with less harmonics.The series H-bridge multilevel converter has the advantages of high output voltage, high power, lower harmonic content in line and motor sides and high input power factor. In addition, because of blocking design, it is easier to raise output voltage, trouble shooting and maintains. Moreover, the converter has no specialdemands on the motor, so it is good for revamping old systems.This dissertation overviews the current development situation of high voltage high power converter, and introduces the topology structure and working principle. In the paper it makes focal points of the zig-zag transformer’ influences on the harmonics of line side and pulse shifting control influence on the harmonic of motor side. The theoretical computation and computer simulation waveforms are presented. Finally the engineering design parameters of the system and the experimental waveforms are given. From experimental results we can see that the real test results are consistent with the theoretical analysis. The equipment of series H-bridge converter has been test running now in Taigang.更多还原