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Active Harmonic Filter (AHF)

Active Harmonic Filter(AHF)

Also known as the Active Power Filter, it is the latest solution to solve the power quality problems caused by harmonics. It is suitable for various industries and market segments with nonlinear loads.

Active harmonic filter OR Active Power Filter is a versatile solution, easily tailored to deliver power factor improvement, voltage variation control, flicker mitigation, and load balancing functionality, and highly improved power quality in networks while reducing harmonic pollution. Active Harmonic Filter can realize 2nd to 50th harmonic compensation.

Harmonics: what do they cause?

Overheating and vibrations with premature aging of all parts, with short- and medium-term effects on life expectancy
Premature aging capacitors and damage due to resonance
Faults on power electronics equipment (e.g., VFD)
Damage to printed circuit board components
Overload of the neutral wire
MCCB and contactor interruption faults

Working of Active Harmonic Filter(AHF)

CT continuously measures the load current (which includes both fundamental and harmonic components)
The measured current is sent to the DSP (Digital Signal Processor) or microcontroller in the AHF
Real time FFT harmonic detection is applied to break down the complex current waveform into its frequency components
This is done using an IGBT PWM inverter AHF- “Equipped with a high-speed IGBT PWM inverter, the Active Harmonic Filter dynamically responds to load variations, delivering consistent THD reduction even under rapidly changing conditions”
The compensating harmonic current is injected into the line through a coupling inductor

The compensating harmonic current is injected into the line through a coupling inductor
This current cancels out the harmonic components in the load current.
The source (utility or generator) now supplies only the fundamental current.
To meet the increasing demand for power quality compliance, our IEEE 519 compliant harmonic filters are engineered to deliver precise and reliable Total Harmonic Distortion (THD) reduction.
The AHF helps maintain Total Harmonic Distortion (THD) reduction below 5%, making your system fully IEEE 519 compliant.
Through dynamic VAR injection, AHF contributes to system voltage control and power quality improvement. They can correct both lagging (inductive) and leading (capacitive) power factors—suitable for mixed loads.

Modular design

Modular compact active harmonic filters, wall-mounted and rack-mounted structures, and fine capacity allocation can fully meet customer needs and are suitable for applications with limited space and renovation projects. Easy to transport and replace, easy to integrate into the cabinet.

Multiple AHF modules (rack type) housed in a single integrated panel for space-saving and centralized harmonic compensation.

Eliminating Neutral Current with AHF

Neutral Current Elimination with AHF Active Harmonic Filter can reduce neutral current. significantly, especially in three-phase four-wire systems where nonlinear single-phase loads (like computers, LED lights, SMPS, etc.) generate triplen harmonics (3rd, 9th, 15th…).

Since Active Harmonic Filter cancels the triplen harmonics at the source, They do not add up in the neutral, leading to a major
drop in neutral current.