【作者】 王琳；

【导师】 孙正鼐；

【作者基本信息】 哈尔滨工业大学 ， 电气工程， 2018， 硕士

【摘要】 串联型多脉波整流器在大功率交流电机调速、蓄电池充电等场合有着广泛应用。传统串联型多脉波整流器单独使用无源或有源谐波抑制方法,难以兼顾交、直流侧的电能质量。为此,本文从建立串联型多脉波整流器的解析模型入手,研究直流侧无源谐波抑制方法、混合谐波抑制方法及其负载适应性。为确定串联型12脉波整流器交、直流侧电量的定量关系,并为直流侧谐波抑制奠定理论基础,建立了带恒压负载的串联型12脉波整流器的解析模型。根据串联型12脉波整流器的结构,研究其等效模型以及等效电流源波形;应用开关函数法,分析串联型12脉波整流器的工作模态,进一步分析负载电压和隔离变压器输入电压的定量关系;引入等效电阻的概念,并据此建立整流器的解析模型;利用电路方程和安匝平衡原理,计算输入电流、输入功率因数以及整流桥输出电流。仿真和实验结果表明,该解析模型能够准确地描述串联型12脉波整流器的行为特性,且具有结构简单、适应性强等优点。为减小串联型12脉波整流电路中输入电流的谐波含量,提出了一种直流侧无源谐波抑制方法。该方法由注入变压器和单相全波整流电路实现。根据基尔霍夫电流定律,分析无源谐波注入电路的工作模态;分析隔离变压器输入电压24阶梯波的形成过程,确定隔离变压器输入电压、注入电压谐波和负载电压之间的定量关系;从隔离变压器输入电压THD值最小的角度出发,对注入变压器进行优化设计;利用电感方程,并结合归一化方法,计算电感电压和输入电流。仿真和实验结果表明,直流侧无源电压谐波注入法的谐波抑制效果显著,且注入变压器的容量仅占负载功率的2.3%,谐波抑制代价较小。为同时提高串联型多脉波整流器交、直流侧的电能质量,并简化系统结构,降低损耗,提出了一种直流侧混合谐波抑制方法。根据基尔霍夫电流定律,分析混合谐波注入电路的工作模态;分析隔离变压器输入电压36阶梯波的形成过程,确定隔离变压器输入电压、注入电压谐波和负载电压之间的定量关系;从隔离变压器输入电压THD值最小的角度出发,优化设计注入变压器以及开关管的导通角,并设计整流器的控制电路。该方法利用无源方法抑制输入电流中的低次谐波,并增加负载电流脉波数,利用有源方法消除输入电流中的高次谐波。仿真和实验结果表明,使用直流侧混合电压谐波注入法后,整流器交、直流侧的电能质量均显著提高,且注入变压器容量仅占负载功率的2.4%,谐波抑制代价较小。为提高直流侧混合谐波抑制方法的负载适应性,研究了大电容滤波条件下负载参数改变对整流器谐波抑制能力的影响。在电阻负载和阻感负载条件下,根据基尔霍夫电流定律,计算整流桥输出电流和注入变压器原边绕组电流;利用电容方程,并结合基尔霍夫电压和电流定律,分析负载电压和负载电阻之间的关系;分析整流器工作在36脉波整流状态的充要条件,确定输出电容和负载电压之间的关系,并给出不同负载类型下的输出电容选取方法。若使用本文所提出的电容选取方法,仿真和实验结果表明,当电阻负载、阻感负载以及负载突变时,直流侧混合谐波抑制方法仍具有较好的谐波抑制性能。更多还原

【Abstract】 Series-connected multi-pulse rectifier is widely used in large power alternating current motor speed regulation,battery charging and other occasions.The traditional series-connected multi-pulse rectifier may have difficulty in balancing the power quality at AC and DC link simultaneously when using the passive and active harmonic suppression method independently.Therefore,in this paper,the passive harmonic suppression method at DC link,the hybrid harmonic suppression method at DC link and the load adaptability are studied based on the analytical model of the series-connected 12-pulse rectifier.In order to determine the quantitative relation of the electric quantity between AC and DC link of the series-connected 12-pulse rectifier,and settle the theoretical foundation for the harmonic suppression thechnology at DC link,an analytical model of the series-connected 12-pulse rectifier with constant-voltage load is established.Through the description of the structure of the rectifier,the equivalent model of the rectifier and the equivalent current source waveform are obtained.According to the switching function method,working mode of the rectifier is analyzed,and the quantitative relationship between the load voltage and the input voltage of the isolation transformer is determined.By introducing the concept of the equivalent resistance,the analytical model of the rectifier is established.Using the circuit equation and ampere balance principle,the expressions of input current,input power factor and output current of the rectifier bridge are obtained.The simulation and experimental results show that the analytical model can describe the characteristics of the series-connected 12-pulse rectifier exactly,and has the merits of simple structure and strong adaptability.For the sake of reducing the harmonic content of the input current in series-connected 12-pulse rectifier,the passive harmonic suppression method at DC link is studied.This method is implemented by an injection transformer and a single-phase full wave rectifier circuit.According to Kirchhoff’s current law,the working mode of the passive harmonic injection circuit is analyzed.The formation process of the 24 step wave input voltage of the isolation transformer is analyzed,and the quantitative relation among the input voltage of the isolation transformer,the injecting voltage harmonics and the load voltage is determined.From the perspective of the minimum harmonic content of the input voltage of the isolation transformer,the optimization design of the injection transformer is carried out.Using inductance equation and normalization method,the inductance voltage and input current are calculated.The simulation and experimental results show that the harmonic suppression effect of the passive voltage harmonic injection method at DC link is remarkable,and the capacity of the injection transformer is only 2.3% of the load power,the harmonic suppression cost is small.In order to improve the power quality at AC and DC link of the series-connected multi-pulse rectifier simultaneously,and simplify the structure of the system and reduce the loss,a hybrid harmonic suppression method at DC link is proposed.According to Kirchhoff’s current law,the working mode of the hybrid harmonic injection circuit is analyzed.The formation process of the 36 step wave input voltage of the isolation transformer is analyzed,and the quantitative relation among the input voltage of the isolation transformer,the injecting voltage harmonics and the load voltage is determined.From the perspective of the minimum harmonic content of the input voltage of the isolation transformer,the injection transformer and the conduction angle of the switch are optimized,and the control circuit of the rectifier is designed.This method uses passive method to suppress low order harmonics in input current and increase the pulse number of load current,and uses active method to eliminate high order harmonics in input current.The simulation and experimental results indicate that,after using the hybrid voltage harmonic injection method at DC link,the power quality of the rectifier at AC and DC link is significantly improved,and the capacity of the injection transformer accounts for only 2.4% of the load power,the cost of harmonic suppression is small.In order to improve the load adaptability of the hybrid harmonic suppression method at DC link,the influence of the load parameter on the harmonic suppression ability of the rectifier is studied under the condition of large capacitance.Under the condition of resistance load and resistance-inductance load,the output current of the rectifier bridge and the primary winding current of the injection transformer are calculated according to Kirchhoff’s current law.Using the capacitance equation and combining the Kirchhoff’s voltage law and Kirchhoff’s current law,the relationship between the load voltage and the load resistance is analyzed.Through the analysis of the necessary and sufficient condition for the rectifier working in 36-pulse rectifying state,the relation between the output capacitor and load voltage is obtained,and the selection method of the output capacitor under different load types is given.If the capacitor selection method proposed in this paper is used,the simulation and experimental results show that the hybrid harmonic suppression method at DC link still has good harmonic suppression performance under the condition of resistance load,resistance-inductance load and load mutation.更多还原