Power Engineer's Handbook - Collection of Various Filter Circuits 2

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Power Engineer's Handbook - Collection of Various Filter Circuits 2 [Copy link]

2

[size =17px]CLC П type filter

[align= left]1. Introduction to working principle

[font =-apple-system-font, BlinkMacSystemFont, "]a. When a positive pulse is input, C1 is charged first, and the charging current is ic1, which is quickly charged to the peak voltage Vi of the pulse. At the same time, there is also a linearly increasing current in the inductor L, and the current is stored in L. Magnetic energy. As the current increases, more and more magnetic energy is stored. The capacitor C2 is also charged with voltage through the inductor L. The charging current is ic2. The voltages on C2 and C1 are basically equal. The current IRL in the load RL is also determined by the input Pulse supply.

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b. When the input positive pulse disappears, the current of the load RL is provided by two paths. One path is the current provided by the discharge of C2, which is -ic2, and the other path is the current provided by the magnetic energy stored in the inductor L, which is converted into electrical energy and connected in series with the voltage on C1 to provide -ic1. The current in the load RL is equal to the sum of the discharge currents of the two capacitors, that is, IL = - (ic2 + ic1). (51, 51, 51)]

[color =rgb(51, 51, 51)]c. For DC: C1 and C2 in the CLC filter, It is equivalent to an open circuit, and the inductive reactance of the inductor L to the DC component is equal to zero, which is equivalent to a short circuit, so the DC component can pass through the inductor L smoothly.

[align= d. For AC: the larger the capacitor, the more it will short-circuit. , and the inductor has a large inductive reactance to various sine waves, so the AC component cannot pass, or only a small amount passes.

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[ size=17px]2. Advantages: The output DC voltage is high and can reach the peak voltage of the rectangular wave. It is suitable for occasions where the load current is large and the output voltage pulsation is required to be small.

3. Weakness: Used in power supplies without voltage stabilization circuits, the load capacity is poor.[/ color]

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4. CLC П-type filters are often used in pulse-amplitude switching regulated power supplies. The larger the capacitance and inductance, the better the filtering effect.

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DLC type filter

1. Introduction to the principle

[color=rgb(51, a.When the secondary winding of the transformer is positive at the top and negative at the bottom, since the voltage output by the secondary winding of the transformer is a rectangular wave with positive and negative alternation, D1 is added to rectify and remove the negative half cycle. After the positive half cycle is rectified by D1, the current passes through the inductor L to store magnetic energy. Part of this current charges C1, and the other part is used for the load RL, and D2 is cut off.

b. When the input positive pulse disappears, the self-inductance voltage generated by the secondary winding of the transformer is negative at the top and positive at the bottom, so the rectifier tube D1 is cut off, and the filter has no input voltage. The current supply of the load RL consists of two parts. One part is converted from the magnetic energy stored in the inductor into electrical energy. The current direction is consistent with the original current direction, and forms a loop current iL through the freewheeling diode D2. The other is the current provided by the discharge of C1, which is -ic1.

2. DLC filter, the output DC voltage is the average value of its input rectangular wave voltage.

3. DLC filter is often used in pulse width switching power supply. The output end of DLC needs to be connected to the ground in parallel with a resistor, which is usually called "release resistor". Generally, 30-50mA current is enough in the release resistor.

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CRC П filter

[size= 17px]1. Introduction to working principle

[align=left ]a. The rectified output voltage is first filtered by capacitor C1, and most of it is The AC component is filtered out, and the voltage after passing through C1 is added to the RC filter circuit composed of RL and C2. Capacitor C2 further filters the AC component.

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[ size=17px]b. The small capacitor C1 has almost no inductance and its capacitive reactance is very small, so high-frequency interference components can be easily filtered to the ground through the small capacitor C1, which has a better effect on filtering high-frequency AC interference.

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[ size=17px]c. The capacitor has a large capacity (C2>C1), and the low-frequency AC component flows through C2, which has a better filtering effect on low-frequency AC interference.

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[ size=17px]d. Resistance has voltage drop and power loss for both AC and DC, so CRC is only suitable for occasions with small load current.

[size= 15px] c. The capacitor has a large capacity (C2>C1), and the low-frequency AC component flows through C2, which has a better filtering effect on low-frequency AC interference.

d. Resistance has voltage drop and power loss for both AC and DC, so CRC is only suitable for occasions with small load current.

c. The capacitor has a large capacity (C2>C1), and the low-frequency AC component flows through C2, which has a better filtering effect on low-frequency AC interference. d. Resistance has voltage drop and power loss for both AC and DC, so CRC is only suitable for occasions with small load current.

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小高1203

After learning, how well does the DLC star filter circuit suppress the interference signal coupled between the primary and secondary sides of the transformer? Transformers often self-couple common-mode signals, resulting in excessive EMI, which is quite annoying.

通途科技

Full of useful information, benefited a lot, let's work together, thank you for sharing! ! ! !