VMIVME-7700-350-007700-111000-H VMEbus单板计算机

VMIVME-7700-350-007700-111000-H VMEbus单板计算机

VMIVME-7700-111000 整流电路会产生谐波电流，这种谐波电流在供电系统的阻抗上产生电压降，导致电压波型发生畸变，这种畸变的电压对于许多电子设备形成干扰（因为大部分电子设备仅能工作在正弦波电压条件下），常见的电压畸变是正弦波的顶部变平。谐波电流一定时，电压畸变在弱电源的情况下更加严重，这种干扰的特征是会对使用同一个电网的设备形成干扰，而与设备与变频器之间的距离无关；

由于负载电压为脉冲状，因此变频器从电网吸取电流也是脉冲状，这种脉冲电流中包含了大量的高频成分，形成射频干扰，这种干扰的特征是会对使用同一个电网的设备形成干扰，而与设备与变频器之间的距离无关；

射频辐射干扰来自变频器的输入电缆和输出电缆。在上述的射频传导发射干扰的情形中，变频器的输入输出电缆上有射频干扰电流时，由于电缆相当于天线，必然会产生电磁波辐射，产生辐射干扰。变频器输出电缆上传输的PWM电压，同样包含丰富的高频的成分，会产生电磁波辐射，形成辐射干扰。辐射干扰的特征是，当其他电子设备靠近变频器时，干扰现象变得严重。

根据电磁学的基本原理，形成电磁干扰必须具备三要素：电磁干扰源、电磁干扰途径、对电磁干扰敏感的系统。为防止干扰，可采用硬件抗干扰和软件抗干扰。其中，硬件抗干扰是*基本和*重要的抗干扰措施，一般从抗和放两方面入手来抑制干扰，其总体原则是抑制和消除干扰源、切断干扰对系统的耦合通道、降低系统干扰信号的敏感性。具体措施在工程上可采用隔离、滤波、屏蔽、接地等方法。以下内容是解决现场干扰的主要步骤：

采用软件抗干扰措施

具体来讲就是通过变频器的人机界面下调变频器的载波频率，把该值调低到一个适当的范围。如果这个方法不能奏效，那么只能采取下面的硬件抗干扰措施。

VMIVME-7700-350-007700-111000-H VMEbus单板计算机

The VMIVME-7700-111000 rectifier circuit generates a harmonic current, which creates a voltage drop in the impedance of the power supply system, resulting in a distortion of the voltage pattern, which interferes with many electronic devices (because most electronic devices can only operate under sine wave voltage conditions). A common voltage distortion is the flattening of the top of the sine wave. When the harmonic current is constant, the voltage distortion is more serious in the case of weak power supply. The characteristic of this interference is that it will interfere with the equipment using the same power grid, and it is independent of the distance between the equipment and the frequency converter.

Since the load voltage is pulsed, the current absorbed by the inverter from the power grid is also pulsed. This pulse current contains a large number of high-frequency components, forming RF interference. This interference is characterized by interference with the equipment using the same power grid, and has nothing to do with the distance between the equipment and the inverter.

Rf radiation interferes with the input and output cables from the frequency converter. In the above case of RF conduction emission interference, when there is RF interference current on the input and output cables of the frequency converter, electromagnetic wave radiation will inevitably be generated, resulting in radiation interference because the cable is equivalent to the antenna. The PWM voltage transmitted on the output cable of the inverter also contains rich high-frequency components, which will produce electromagnetic radiation and form radiation interference. The characteristic of radiation interference is that when other electronic devices are near the frequency converter, the interference phenomenon becomes serious.

According to the basic principles of electromagnetism, the formation of electromagnetic interference must have three elements: electromagnetic interference source, electromagnetic interference path, and electromagnetic interference sensitive system. In order to prevent interference, hardware anti-jamming and software anti-jamming can be used. Among them, hardware anti-interference is the most basic and most important anti-interference measures, generally from the anti-and put two aspects to suppress interference, the overall principle is to suppress and eliminate the source of interference, cut off the interference to the system coupling channel, reduce the sensitivity of the system interference signal. Specific measures can be used in engineering isolation, filtering, shielding, grounding and other methods. The following are the main steps to address field interference:

Software anti-jamming measures are adopted

Specifically, it is to reduce the carrier frequency of the inverter through the man-machine interface, and reduce the value to an appropriate range. If this method does not work, then can only take the following hardware anti-jamming measures.