逆变器并联永磁同步电机变频调速关键技术研究

发布时间：2018-08-05 19:39

【摘要】：电力推进系统作为船舶的动力,与机械推进系统相比优势明显,具有广阔的市场前景。逆变器并联在船舶电力推进这种低压大电流场合能够有效增大系统容量,同时逆变器并联能够增强系统灵活性。本文针对船舶电力推进逆变器并联的环流均流问题及传动控制的特殊问题进行了研究。公共直流母线逆变器并联运行时,在零序电压的作用下造成环流,环流不仅浪费了系统的容量,造成额外的损耗,还会对控制造成干扰。本文分析了公共直流母线逆变器并联载波移相时各类谐波电压下的环流回路,讨论了零序环流抑制方法。另外由于并联逆变器器件参数的杂散特性,各并联逆变器会出现不均流的情况,本文提出平均电流控制方法,采用双内环控制来均衡并联逆变器输出电流。独立母线逆变器并联运行时,在特定脉冲组合下,环流回路串入电容形成环流回路电动势,造成环流。分析了载波移相时独立母线三电平逆变器并联各类谐波电压下的环流回路以及影响环流大小的因素,给出了环流抑制的方法。针对船舶推进电机系统设计的特殊问题,为防止逆变器过调制,添加电压闭环反馈控制,对电机进行弱磁,降低额定速度额定负载运行时电机反电动势,有效避免电机电流振荡；在功率限制的问题上,添加功率环,实时调节电机速度给定,使得在任意负载下,电机功率都不超过功率限值,保证船舶电网的安全稳定运行；针对零速带载的运行工况,改进原有的三电平中点控制算法,在零速度大负载的情况下,能够保持中点电位波动在合理范围之内,保证逆变器的安全稳定运行。经过仿真和实验验证,逆变器并联双内环控制能够有效实现均流,同时环流得到有效抑制。现场实际运行情况表明,在功率限制及零速带载情况下系统都能稳定运行。
[Abstract]:As the power of ship, electric propulsion system has obvious advantages compared with mechanical propulsion system and has a broad market prospect. The parallel inverter can effectively increase the system capacity and enhance the system flexibility in the case of marine electric propulsion with low voltage and high current. In this paper, the circulating current sharing problem of marine electric propulsion inverter and the special problem of transmission control are studied. When the common DC bus inverter is operated in parallel the circulation is caused by zero sequence voltage which not only wastes the capacity of the system but also causes extra loss and disturbance to the control system. In this paper, the loop of common DC bus inverter with parallel carrier phase shift is analyzed, and the zero sequence loop suppression method is discussed. In addition, due to the spurious characteristics of the device parameters of parallel inverter, the parallel inverter will have uneven current. In this paper, an average current control method is proposed, in which the output current of parallel inverter is equalized by double inner loop control. When the independent busbar inverter is running in parallel, under the special pulse combination, the loop circuit cascade capacitance forms the loop electromotive force, resulting in the circulation. This paper analyzes the circulation loop and the factors affecting the circulation size of the independent busbar three-level inverter with parallel harmonic voltages when the carrier phase is shifted, and gives the method of loop suppression. Aiming at the special problems in the design of marine propulsion motor system, in order to prevent the inverter from overmodulation and to add voltage closed-loop feedback control, the motor is weak in magnetic field and the rated speed is reduced when the rated load is running. In the problem of power limitation, the power loop is added to adjust the speed of the motor in real time, so that the power of the motor does not exceed the power limit under any load, so as to ensure the safe and stable operation of the ship power network. In view of the operation condition of zero speed band load, the original three-level neutral point control algorithm is improved, which can keep the neutral point potential fluctuation within a reasonable range and ensure the safe and stable operation of the inverter under the condition of zero speed and large load. The simulation and experiment show that the parallel double inner loop control of the inverter can effectively realize the current sharing and the circulation is effectively suppressed. The field operation shows that the system can operate stably under the condition of power limit and zero speed load.
【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】：U664.14

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