Research on Reduction of EMI Produced by a Valiable-Speed Motor Drive System with a PWM invester

本研究的目的在于阐明电压型PWM逆变器调速交流电动机驱动系统中辐射噪声和传导噪声的产生机理，并提出降低噪声的方法。首先，针对三相交流电动机，提出了一种仅由三个电容器组成的高频等效电路，每个电容器连接在电动机端子和电动机机架之间。使用感应电机驱动系统（3.7 kW）进行的实验和使用电路模拟器进行的仿真表明，所提出的高频等效电路可以足够准确地模拟由PWM逆变器开关操作引起的共模电流和法向电流。此外，基于所提出的等效电路，我们开发了"共模Transformer（CMT）"，它只作为共模电流的电阻，和"正常模式滤波器（NMF），它可以转储高频振荡电流流过电机两相之间，并设计 ...更多信息 对这些组分的方法进行了详细研究。此外，通过理论和实验证明，CMT和NMF不仅可以降低EMI，还可以降低逆变器开关瞬间出现在电动机端子上的浪涌电压。另一方面，与传统的元件相比，我们提出了使用有源元件消除共模电压的"有源共模噪声消除器（ACC）"。通过实验验证了该方法的可行性和效果，并对设计方法进行了详细的研究。ACC的专利申请已通过日本科学促进会向日本和美国提出。ACC已通过日本科学振兴会向日本和美国申请了专利。最后，我们相信本研究所取得的成果有助于推进电力电子设备中EMI/EMC的理论和系统研究。少

This research aimes to clarify mechanism of generating both radiative and conductive noises and to develop reduction methods of the noises, in variabile-speed AC motor drive system using a voltage-source PWM inverter.First of all, for a three-phase AC motor, we have proposed a high-frequency equivalent consisting of only three capacitors each of which connects between a motor terminal and a motor frame. Experiment using an induction motor drive system (3.7 kW) and simulation using a circuit simulator have demonstrated that the proposed high-frequency equivalent circuit can simulate both common- and normal-mode currents caused by switching operation of the PWM inverter with enough accuracy. Moreove, based on the proposed equivalent circuit, we have developed "common-mode transformer (CMT), " which acts as a resistance only to the common-mode current, and "normal mode filter (NMF), " which can dump the high-frequency oscillating current flowing between two phase of the motor, and design … More methods for these components have been studied in detail. In addition, it has been shown theoretically and experimentally that the CMT and NMF can reduce not only EMI but also serge voltage appearing on a motor terminal at a switching instant of the inveter.On the other hand, we have proposed an "active common noise canceler (ACC)" which can cancel the common-mode voltage using an active element, in contrast to the conventional components. The operation and effect have been confirmed by some experiments, and the design method has been studied in detail. The patent applications for the ACC have been made to Japan and United States through the Japan Society for the Promotion of Science. The patent applications for the ACC have been made to Japan and United States through the Japan Society for the Promotion of Science.Finaly, we believe that the results obtained by this research contribute to advancement of theoretical and systematic research of EMI/EMC occurring in power electronics apparatus. Less