The 4 Key Differences Between Active Filtering And Passive Filtering

1. Working Principle
The passive filter is composed of passive components such as LC, and is designed to have a low impedance at a certain frequency, to分流 the harmonic current of the corresponding frequency. Its behavior mode is to provide a passive harmonic current bypass channel. While the active filter is an electrical energy conversion device composed of power electronic components and DSP, which detects the harmonic current of the load and actively provides the corresponding compensation current. The compensated source current is almost a pure sine wave, and its behavior mode is an active current source output.
2. Impedance Impact
Passive filters are severely affected by system impedance, posing risks of harmonic amplification and resonance; however, active filters are not affected by this.
3. Frequency Impact
The resonant point of the passive filter shifts and the effect is reduced; the active filter is not affected.
4. Load Impact
The passive filter may be damaged due to overload; the active filter does not have the risk of damage. When the harmonic quantity exceeds the compensation capacity, only insufficient compensation effect occurs. The compensation effect of the passive filter changes with the load variation; the active filter is not affected by the load variation.
5. Equipment cost
The cost of passive filters is lower; that of active filters is much higher.

Jinneng electric low-voltage active power filter device (APF) for electricity is applicable to voltage systems ranging from 380V to 660V and serves as a harmonic control solution. This device employs an advanced dynamic real-time tracking compensation method to eliminate grid harmonics. By continuously detecting the harmonic and reactive components of the load, it uses PWM conversion technology to inject currents of equal magnitude but opposite direction to the harmonic and reactive components into the power supply and distribution system. This achieves the functions of suppressing harmonics and dynamically compensating reactive power.