PWM逆变器输出dvdt抑制技术的仿真研究.doc

哈尔滨工业大学工学硕士学位论文 哈尔滨理工大学学士学位论文 - PAGE II - - PAGE II - PWM逆变器输出dv/dt抑制技术的仿真研究 摘要 高变化频率(2-20KHZ)在现代的能量高于500KW的双极性绝缘晶体管技术中是很平常的现象，然而，高变速和高级的脉宽调制逆变系统有效地提高了脉宽调制逆变器对电动机的供给情况，小于0.1μs时间内的0～650V的高电压时间升高频率对发动机绝缘体起到了不利的影响，这些剧烈上升和下降的脉冲导致电动机电压的分布不均匀，尤其在开关变化的过程中，这导致绝缘物质的退化以至电动机的失灵，而且dv/dt会导致轴承电流的破坏和电磁干扰。 有两种主要的降低由电动机终端过电压引起的电动机绝缘体压力的方法：1、过滤技术 2、增加磁线的绝缘能力，以抵制较高的dv/dt。一种特殊设计的放置在电动机终端的分流滤波器已经被证明能够有效的抑制过电压现象。然而，在许多应用中，电动机的终端很难达到，例如，驱动潜水泵时，几乎找不到方便的放置整流器终端滤波器的地方 为了解决这些涉及到的问题，我们将研究逆变器输出滤波器在设计方面的问题。对于逆变器输出滤波器，如何降低滤波器的输出脉冲的dv/dt，使其低于限定的临界值是最重要的问题，这一问题解决了，电动机的终端就不会发生过电压的现象。同时，滤波器的大小﹑成本﹑重量﹑老化等也要尽可能的完善，滤波器在逆变器全部v/f范围内的操作一通过仿真和实验得到证实，逆变器输出滤波器将与安置在电动机终端的分流滤波器相比较。 关键词　PWM逆变器；长线电缆；反射；上升时间 Research on PWM inverter output dv/dt filter Abstract High switching frequencies (2–20kHz) are common with the present-day insulated gate bipolar transistor (IGBT) technology for power levels over 500 kW. While the high switching speeds and advanced PWM schemes significantly improvethe performance of the PWM-inverter-fed induction motors, the high rate of voltage rise of 0–650 V in less than 0.1 s has adverse effects on the motor insulation .These steep rising and falling pulses lead to an uneven distribution of voltages within the motor, especially during switching transitions. This contributes to insulation deterioration and subsequent failure of the motor. In addition, the contributes to damaging bearing currents and electromagnetic interference (EMI) . There are two primary means of reducing the motor insulation stresses due to motor terminal over-voltages: 1 filtering techniques 2 increasing the insulation strength of the magnet wire to withstand a high . A specially designed shunt filter installed at the motor terminals has been shown to effectively dampen the voltage overshoot . However, in many applications,the motor terminals may not be accessible, as in drives for submersible pumps, where it may be more convenient to install a filter at the inverter terminals.In response to these concerns, this pap