How inverter filters work

Categories: Industry news




As the name implies, the inverter filter is a special filter specially developed for the characteristics and laws of the harmonics generated by the inverter. It is an LC filter. Inverter Input Filter Overview Inverter filters are mainly passive components consisting of inductors, capacitors and resistors.

It is a low-pass filter that can pass power frequency signals unobstructed and suppress high-frequency electromagnetic interference (usually can suppress the interference noise frequency at 50/60~1kHz). The inverter filter is a bidirectional reversible device, which can prevent the electromagnetic noise on the grid from entering the device through the power supply, and also prevent the electromagnetic noise of the device itself from polluting the grid.

Inverter filters are an effective tool to suppress conducted interference.



1. The inverter filter is specially designed according to the electromagnetic compatibility characteristics of the spectral components, which can interfere with the power grid and other digital electronic equipment when the inverter is working.

2. Installed between the motor and the inverter and between the power supply and the inverter.

3. Small, fanless, and tested for high-performance materials and components in the harshest environments. Parameter 1. Insertion loss Insertion loss is an important parameter to measure the electrical performance of the inverter filter. Insertion loss is the ratio of the noise voltage transmitted from the noise source to the load when the filter is not used to the noise voltage transmitted from the noise source to the load when the filter is inserted. Insertion loss is tested on a system with an input/output impedance of 50Ω, and the result is usually expressed as an attenuation curve (in decibels) in the frequency band of interest.

4. Leakage current The leakage current of the inverter filter refers to the current flowing between the live wire and the neutral wire and between the enclosures under the voltage/frequency condition of 250VAC/50Hz. The magnitude of the leakage current mainly depends on the common mode capacitance in the inverter filter. From the perspective of insertion loss, the larger the common-mode capacitance, the better the electrical performance, and the greater the leakage current at this time. But from a safety point of view, the leakage current should not be too large, otherwise it will not meet the requirements of safety standards. Especially for some medical equipment, the leakage current is required to be as small as possible.

Therefore, the capacity of the common mode capacitor should be determined according to the specific equipment requirements.