1) Mainly used for electromagnetic interference of DC power lines;
2) Excellent common mode and differential mode insertion loss over a wide frequency band (10KHZ - 30MHZ);
3) high performance, low temperature rise, low price;
4) It can assist various electronic devices that use DC power to meet VDE and FCC standards.
The filter circuits commonly used in power supply filters are passive filtering and active filtering. The main forms of passive filtering are capacitive filtering, inductive filtering and complex filtering (including inverted L-type, LC filtering, LCÏ€-type filtering and RCÏ€-type filtering, etc.). The main form of active filtering is active RC filtering, also known as electronic filters. The magnitude of the pulsating component in the direct current is represented by the pulsation coefficient S. The larger the value, the worse the filtering effect of the filter.
Pulsation coefficient (S) = fundamental maximum of output voltage AC component / DC component of output voltage
The principle of the line filter is an impedance matching network: the greater the impedance adaptation between the input and output sides of the line filter and the power supply and load side, the more effective the attenuation of electromagnetic interference is.
The specific working principle is as follows : After the alternating current is rectified by the diode, the direction is single, but the size (current intensity) is still constantly changing. This pulsating DC is generally not directly used to power the radio. To turn the pulsating DC into a waveform-smooth DC, you need to do another "filling in" work, which is filtering. In other words, the task of filtering is to reduce the fluctuation component of the rectifier output voltage as much as possible, and transform it into a nearly constant DC power.
According to the electromagnetic disturbance characteristics of the power port, the power supply EMI noise filter is a passive low-pass filter that transmits AC power to the power supply without attenuation, and greatly attenuates the EMI noise transmitted with the AC, and at the same time effectively suppresses The EMI noise generated by the power supply devices prevents them from entering the AC grid and interfering with other electronic devices.
3, power filter structureThe typical structure of the line filter is shown in the figure below. This is a passive network structure that is suitable for both AC and DC power supplies and has bidirectional suppression. Insert it between the AC grid and the power supply, which is equivalent to adding a blocking barrier between the EMI noise of the two, so that a simple passive filter acts as a two-way noise suppression, thus in various electronic A wide range of applications are available in the device.
In the figure, Cx is a differential mode capacitor, generally called X capacitor. The capacitance should be chosen to be 0.01-2.22μF. CY1 and CY2 are common mode capacitors, generally called Y capacitors. The capacitance is about a few nanofarads (nF) to several. Ten nano law. The capacitance of C3 and C4 should not be too large, otherwise it will easily cause the risk of leakage of filters and even casings. L is a common mode choke coil, which is a pair of coils wound in the same ferrite ring in the same direction, and the inductance is about several millihenries (mH). For the common mode interference current, the magnetic fields generated by the two coils are in the same direction, and the common mode choke coil exhibits a large impedance, thereby attenuating the interference signal; and for the differential mode signal (here is the low frequency supply current) ), the magnetic field generated by the two coils cancels, so it does not affect the power transmission function of the circuit.
The power filter is designed for the characteristics of electromagnetic interference of the power port. It is generally a frequency selective two-port network composed of an inductor, a capacitor, a resistor or a ferrite device. It is actually a type of filter, which is called according to the working principle. It is a reflective filter. It provides a high series impedance and low parallel impedance within the filter stopband, which severely mismatches the impedance and load impedance of the noise source, thereby transmitting unwanted frequency components back to the noise source.
When we choose the power filter, we should mainly consider three aspects: first, voltage and current, then insertion loss, and finally structure size. Since the interior of the filter is typically potted, environmental characteristics are not a major issue. However, the temperature characteristics of all potting materials and filter capacitors have an effect on the environmental characteristics of the power supply filter.
Figure 3 Basic circuit diagram of the power filter
Conductor Inspection Bicycles or Car of various types including Spacer Bike, Spacer Car, 1 bnd Spacer car, 2 bnd Spacer car, Four Bunle Spacer car, Spacing Bike, Spacing Car, Spacer, which is widely used to used to install or repair accessories on splited conductors. It can be going through on splited conductors so it is very convenient for working and repairing accessories while stringing electric power lines. It is made of high quality and high strength steel material with reasonable volume, light weight, easy to operate. By high quality material and good design, these kind of Spacer Bike or Car can be durable and long service life. we are a professional Chinese exporter of Spacer Bike or Car and we are looking forward to your cooperation.
Overhead line bicycles, conductor inspection bicycles, lineman spacer buggy, spacer carts, spacer buggy
Yangzhou Qianyuan Electric Equipment Manufacturing & Trade Co.Ltd , https://www.qypowerline.com