The difference between active harmonic filter and static var generator

More and more customers usually ask us about the difference between active harmonic filter and static var generator, now let me give you the answer.

Active power filter APF is a new type of power harmonic control equipment made of modern power electronics technology and digital signal processing technology based on high-speed DSP devices. It consists of two main parts: command current operation circuit and compensation current generation circuit. The command current operation circuit monitors the current in the line in real time, converts the analog current signal into digital signal, sends the signal to the high-speed digital signal processor (DSP) for processing, separates the harmonics from the fundamental wave, and sends the drive pulse to the compensation current generating circuit in the form of pulse width modulation (PWM) signal, drives the IGBT or IPM power module. A compensating current with equal amplitude and opposite polarity of harmonic current is generated and injected into the power grid to compensate or cancel harmonic current and actively eliminate power harmonics.

Static reactive power generator is the self-commutating bridge circuit through the reactor or directly connected to the power grid, adjust the phase and amplitude of the AC side of the bridge circuit output voltage, or directly control its AC side current, so that the circuit absorbs or sends out the reactive power to meet the requirements, to achieve the purpose of dynamic reactive power compensation.

Active harmonic filter and static var generator some similar as below:

1.The external dimensions of APF and SVG are the same. Standardized modules make production more efficient and convenient to use.

2.The monitoring touch screen interface of APF and SVG is the same.
3.APF and SVG have the ability to simultaneously compensate for harmonics, reactive power and regulate three phase unbalance current.

4.The internal structure is the same.

Active harmonic filter and static var generator difference as below:

1.Different application scenarios. APF is mainly used for filtering, while SVG is mainly used for compensating reactive power and they are applied in different situations with different requirements.

2.The selection andcontrol procedures of internal components are different. Because the main functions of the two are different, they target different current frequencies.

3.There are differences in filtering range and capability. APF can filter out 2-50 harmonics, while SVG can only filter out 2-13 harmonics. APF has better filtering performance, while SVG can only filter our low order harmonics with approximately half of its capacity.

4.There are differences in parameter settings. SVG is generally set to compensate for reactive power priority by default, APF is generally set to compensate for harmonics first by default.