双三电平逆变器容错控制策略研究

发布时间：2018-05-14 16:12

本文选题：双三电平逆变器 + 容错控制　；参考：《中国矿业大学》2016年硕士论文

【摘要】：电机调速系统在矿井提升机、电动汽车等行业具有广泛的应用,其可靠性直接关系到整个系统的安全运行。但调速系统中的变流器及其驱动电路较容易发生故障,其可靠性问题始终无法有效解决。双三电平逆变器具有输出电压等级高,输出电平数较多,以及容错能力强等优点,本文以双三电平逆变器拓扑为研究对象,对其容错控制、中点电位平衡、死区补偿、共模电压抑制、矢量控制等方面内容进行了深入研究。本文分析双三电平逆变器拓扑换流情况,根据开关器件的不同导通关断组合归纳出五种不同的输出状态;求解空间电压矢量表达式,绘出空间电压矢量图;探讨死区效应和死区补偿,给出时间补偿和电压补偿两种具体补偿方法;分析开绕组电机数学模型及矢量控制原理,给出矢量控制基本框图。针对任意开关器件开路,本文采用一种线电压坐标系容错算法,该算法使用不产生零序电压和共模电压的零共模电压矢量,通过调整平衡因子实现中点电位平衡,由于故障时开关器件导通顺序不具备正常运行时的对称性,本文改变故障时开关器件导通规则,使之满足容错运行要求。针对任意桥臂故障,本文采用一种双三电平逆变器共母线容错拓扑,在开绕组电机各绕组与直流侧中点之间连接6个双向晶闸管,当逆变器任意一个桥臂短路或开路故障时,切除该桥臂,利用60°坐标系容错算法使系统容错运行。上述故障时,双三电平逆变器最大输出电压下降为正常运行时一半。通过仿真对线电压坐标系容错算法和60°坐标系容错算法进行验证,仿真结果证明了容错算法和死区补偿方法的正确性。针对双三电平逆变器独立母线拓扑,改进任意一侧逆变器故障容错拓扑,使系统从正常运行迅速切换至容错运行。将双向晶闸管引入独立母线拓扑,使任意双桥臂故障时系统仍能降额运行,与单纯切除一侧逆变器的方法相比,本方法可实现两逆变器同时故障时的容错运行,扩大了容错范围。双三电平逆变器独立母线容错拓扑同样适用单桥臂故障,此时,容错时额定转速达到原额定转速的3/4,可应用于对转速要求较高的场合。基于双三电平逆变器拓扑实验平台对本文所提容错控制策略进行了实验验证。证明了容错控制策略、中点电位平衡、矢量控制、死区补偿方法、零共模电压抑制方法的有效性,具有较好的容错效果。
[Abstract]:Motor speed regulation system is widely used in mine hoist, electric vehicle and so on. Its reliability is directly related to the safe operation of the whole system. However, the converter and its drive circuit in the speed control system are prone to malfunction, and the reliability problem can not be solved effectively. Dual-three-level inverter has the advantages of high output voltage level, high output level number, and strong fault tolerance. In this paper, the double three-level inverter topology is taken as the research object, fault tolerant control, neutral-point potential balance, dead-time compensation, etc. The common mode voltage suppression and vector control are studied in detail. In this paper, the topology commutation of dual-three-level inverter is analyzed, five different output states are concluded according to the different on-off combination of switching devices, the expression of space voltage vector is solved, and the space voltage vector diagram is drawn. This paper discusses the dead-time effect and dead-time compensation, gives two specific compensation methods, time compensation and voltage compensation, analyzes the mathematical model and vector control principle of open-winding motor, and gives the basic block diagram of vector control. In this paper, a fault tolerant algorithm of linear voltage coordinate system is used for open circuit of arbitrary switching devices. This algorithm uses zero common-mode voltage vector without generating zero-sequence voltage and common-mode voltage, and realizes neutral-point potential balance by adjusting the balance factor. Due to the fact that the switch on sequence does not have the symmetry in normal operation, the switch on rule is changed in this paper to meet the requirements of fault-tolerant operation. In this paper, a common-bus fault tolerant topology of a two-level three-level inverter is used to connect six bi-directional thyristors between the winding of the open winding motor and the neutral point of the DC side. When any one of the legs of the inverter is short circuit or open circuit fault, The arm is excised and the fault tolerant algorithm of 60 掳coordinate system is used to make the system run fault-tolerant. In the above faults, the maximum output voltage of the double three level inverter is reduced to half of the normal operation. The fault-tolerant algorithm of linear voltage coordinate system and the fault-tolerant algorithm of 60 掳coordinate system are verified by simulation. The simulation results show that the fault-tolerant algorithm and dead-time compensation method are correct. Aiming at the independent bus topology of the two-three-level inverter, the fault tolerant topology of any side inverter is improved so that the system can be switched from normal operation to fault-tolerant operation quickly. The bi-directional thyristor is introduced into the independent bus topology, so that the system can still operate under any double bridge arm fault. Compared with the method of simply removing one side inverter, this method can realize the fault-tolerant operation of two inverters at the same time. The fault tolerance range has been expanded. The fault-tolerant topology of dual three-level inverter is also suitable for single bridge arm fault. In this case, the rated speed of fault tolerance reaches 3 / 4 of the original rated speed, which can be applied to the situation with high speed requirement. The fault-tolerant control strategy proposed in this paper is experimentally verified based on the topology experiment platform of a two-level three-level inverter. It is proved that the fault-tolerant control strategy, midpoint potential balance, vector control, dead-time compensation and zero-common-mode voltage suppression are effective.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM464

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