Passive Harmonic Filter for VFD Systems
Product Overview
The RMRFC-BP series passive harmonic filter is specially designed for frequency converters (VFDs). Developed and manufactured by Hongyan Electric, it applies wide-band Fourier analysis filtering technology and integrates digital monitoring modules to record and analyze key electrical parameters in real time. The system intelligently switches filtering circuits and effectively suppresses 5th, 7th, 11th, and higher-order harmonics, purifying the power network, preventing electromagnetic interference, and significantly improving the power factor of VFD systems. It also provides notable energy-saving benefits for industrial operations.
Key Features
Effectively eliminates harmonic currents and meets GB/IEC harmonic control requirements
Improves system power factor to ≥0.95, reducing energy losses
Supports automatic, intelligent switching and dynamic filtering
Steel-plate enclosure with IP20B protection level
Compact design, easy installation and maintenance
Compatible with VFDs of all major brands
Enhances VFD reliability and prevents harmonic-related malfunctions
Ensures stable system operation and long equipment lifespan
Main Components
Harmonic filter capacitor bank
Harmonic filter reactor
Power switching device (or TSC thyristor switch)
Protection unit
Filter controller
Signal terminal blocks
Technical Specifications
| Item | Specification |
|---|---|
| Installation | Indoor, floor-mounted or wall-mounted |
| Rated voltage | 400V / 525V / 660V |
| Harmonic suppression ratio | ≥70% |
| Protection level | IP20B |
| Operating altitude | ≤2000m |
| Relative humidity | ≤90% (at +20°C) |
| Connection method | Cable or busbar |
| Rated frequency | 50Hz (60Hz optional) |
| System power factor | ≥0.95 |
| Cooling | Natural cooling or forced-air cooling |
| Ambient temperature | –10°C ~ +40°C |
Harmonic Generation & Suppression (Principle)
VFD rectifier circuits generate a large number of harmonic currents. When injected into the power grid, these harmonics distort the voltage waveform, interfere with other electrical equipment, and decrease overall system reliability. According to national harmonic management standards, harmonic currents injected into the grid must be properly filtered to protect downstream electrical equipment and prevent safety hazards.
Since 1993, national standards have regulated the maximum allowable harmonic current for electrical equipment. If the measured harmonic value exceeds the standard, effective filtering must be implemented.
Typical Harmonic Injection of VFDs (Based on 50Hz AC Grid)
| Harmonic Order | 5th | 7th | 11th | 13th | 17th | 19th | 23rd | 25th |
|---|---|---|---|---|---|---|---|---|
| Maximum injection (%) | 38 | 14.5 | 7.4 | 3.4 | 3.2 | 1.9 | 1.6 | 1.3 |
| Average injection (%) | 28 | 9.1 | 7.2 | 4.1 | 3.2 | 2.4 | 1.7 | 1.4 |
Recommended Applications
Variable frequency drive systems
HVAC and compressor systems
Pumps and fans with VFD control
Industrial automation equipment
Production lines with nonlinear loads
Equipment requiring improved power factor and harmonic control
Ordering Information
To configure the correct model, please provide:
Rated voltage (400V / 525V / 660V)
VFD rated power and model
Required harmonic suppression level
Installation method (floor / wall)
Environmental conditions (temperature, altitude, humidity)
Whether TSC thyristor switching is required
Cabinet color or layout preference
