【摘要】 在经由长线缆连接的PWM系统中，变频器输出电压经线缆传输后，会在电机端产生更为严重的过电压现象。本文针对PWM系统下的变频电机产生的过电压问题，以三根单芯线缆为研究对象，分析其长度对于电机端产生的过电压幅值规律。基于传输线理论和基本的电路模型，分析了电机端过电压的产生机理，并通过有限元仿真、理论计算、实际测试，获得了线缆本身的分布电感、分布电阻以及分布电容。同时在仿真软件中搭建变频器、线缆与电机的等效模型，并计算了不同线缆长度下电机端的过电压。最终通过搭建相关实验平台，在同一工况下，将线缆长度分别选为1m、4m、8m、15m,对电机端的过电压进行测试，以验证仿真模型和仿真结果。将仿真结果与实测结果进行对比，两者呈现相同的规律，且误差在合理的范围内，这验证了所搭建电路模型的准确性。更多还原

【Abstract】 In a PWM system connected by a long cable, the output voltage of the inverter will produce a more serious over-voltage phenomenon at the motor end after transmission through the cable. In this paper, three single-core cables are taken as the research object to analyze the over-voltage amplitude rule of the length of the frequency conversion motor under PWM system. Based on the transmission line theory and the basic circuit model, the generation mechanism of motor end over-voltage is analyzed, and then the distributed inductance, distributed resistance and distributed capacitance of the cable are obtained by finite element simulation, theoretical calculation and practical test. At the same time, the equivalent model of the driver, cable and motor is built in the simulation software, and the over-voltage of the motor end under different cable lengths is calculated. Finally, through the establishment of relevant experimental platform, under the same working condition, the length of the cable is changed to 1m, 4m, 8m and 15m, respectively, to test the over-voltage of the motor end, and verify the simulation model and simulation results. Comparing the simulation results with the measured results, the two show the same rule, and the error is within a reasonable range, which verifies the accuracy of the circuit model.更多还原