Common-mode interference suppression device and variable-frequency electric appliance

Abstract

The embodiment of the invention provides a common-mode interference suppression device and a variable-frequency electric appliance. The common-mode interference suppression device comprises a live wire branch, a zero line branch, a ground wire branch, a first filter, a second filter and a third filter, wherein one end of the live wire branch is connected with a live wire of the AC power supply, the other end of the live wire branch is connected with the load branch, and the live wire branch is provided with a first filter; one end of the zero line branch is connected with a zero line of the AC power supply, the other end of the zero line branch is connected with the load branch, and the null line branch is provided with a second filter; and one end of the ground wire branch is connected with the ground wire of the AC power supply, the other end of the ground wire branch is grounded, and the ground wire branch is provided with a third filter. Therefore, case common-mode interference is prevented from being coupled from the power ground wire to the power zero wire and the power live wire through idle coupling between the cables, radiation interference generated by the power ground wire is avoided, common-mode interference suppression can be carried out without increasing the number of filtering stages and increasing the number of turns and the number of magnetic rings, and the filtering cost is reduced.

Description

technical field [0001] The embodiments of the present invention relate to the field of circuit technology, and in particular to a common-mode interference suppression device and a frequency conversion electrical appliance. Background technique [0002] Due to the large operating current of high-power electrical appliances, the interference current generated is also huge. There will be a lot of common-mode interference to the ground, resulting in common-mode interference in different frequency bands (for example, 150KHz-30MHz). Commonly used filters to suppress common-mode interference are common-mode capacitors (also called Y capacitors) and common-mode inductors (also called common-mode choke coils). Block and guide the interference current by way of resistance and bypass drainage. [0003] At present, except that the protective ground of some devices is connected to the chassis, most common-mode interference is bypassed through the Y capacitor of the filter circuit. How...

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Problems solved by technology

However, the common mode interference of the chassis will be coupled from the ground wire of the power supply to the neutral wire and live wire (low frequency) of the power supply through the idle coupling between the cables, resulting in filter failure, and even the radiation interference (high frequency) of the power ground wire itself, which needs to be increased Filtering stages and increasing the number of turns and number of magnetic rings for common mode interference suppression, which further increases the cost of filtering

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