Active Harmonic Filters, Order by Order
An active harmonic filter (AHF) is a parallel-connected device that detects harmonic current and injects opposing compensation current. GY-AHF models compensate selectable 2nd–50th harmonics at ≥95%, with <40 ms full response; selected SiC models offer up to 98.79% measured peak efficiency.
From 15 A Modules to 1,200 A Cabinets
All builds support harmonic-only or harmonic + unbalance compensation, with 100% current-limited output for continuous stability.
| Model | Build | Voltage | Rating | Highlights |
|---|---|---|---|---|
| GY-AHF | Rack / wall module | 220 / 400 V | 15–200 A | 2nd–50th, per-order rate adjustable |
| GY-AHF /3L | Three-level module | 500 / 690 / 800 V | 100 A | Higher-voltage industrial buses |
| GY-AHF-PLUS | High-spec module | 220 / 400 V | 100 / 150 A | Neutral filtering 3× phase current; EMC Class A (RE/CE) |
| GY-AHF-SiC | SiC module (2U) | 220 / 400 V | 100 / 150 A | 98.79% measured peak efficiency; fixed 30 kHz |
| GY-AHF-cabinet | Cabinet system | Project spec | Up to 1,200 A | Up to 8 modules per cabinet (SiC) |
Response <40 ms · harmonic compensation ≥95% (2nd–50th) · unbalance after compensation ≤5% · RS485 communication · unlimited parallel operation.
Built for the Buses That Fail Audits
Order-by-order control
Set the compensation rate per harmonic order (2nd–50th) to hit IEEE 519 / GB 14549 limits exactly where your audit needs it.
Protects the neutral
PLUS and SiC tiers filter zero-sequence harmonics at up to 3× phase current — the cure for overheated neutrals under single-phase electronic loads.
SiC efficiency lead
T-type three-level SiC at a fixed 30 kHz: 98.79% measured peak efficiency, half the footprint, and roughly 10% lower losses than rival SiC units.
Proven at the extremes
Measured projects: data-center THDi 60% to 5%, steel-mill THDi over 30% to under 10%, UPS output THDu 17% to about 3%.
Questions Engineers Actually Ask
What result can I expect after installing an AHF?
With correct sizing, compensated THDi typically lands under 5% — under 3% on the SiC tier. Measured GEYA projects cut a data-center power room from 60% to 5% and a steel mill from over 30% to under 10% on every phase.
How do I size an AHF — what current rating do I need?
Size against the measured harmonic current, not the load current: log THDi at the target bus, take the harmonic RMS current, add 20–30% headroom for load growth, then parallel 15–200 A modules to match. Send us your measurement file and we size it for you.
AHF vs passive LC filters — why go active?
Passive filters only treat the orders they were tuned for, detune as components age, and can resonate with the grid. An AHF adapts in real time across the 2nd–50th spectrum, keeps full performance at partial load, and cannot resonate — one unit replaces a room of tuned banks.
Have a THDi Number to Beat?
Send your power-quality measurement and target standard — our engineers will size the AHF and project the result before you order.
See AHF at work in data centers, high-end manufacturing and all solutions.
