Low-Harmonic Drives / AFE VFDs – Clean Power, Reliable Performance

Harmonic distortion is one of the hidden challenges in modern electrical systems. Whenever a variable-frequency drive (VFD) converts AC power to DC and back again, it can create unwanted current harmonics. Left unchecked, these harmonics cause overheating in transformers and cables, nuisance trips in protective equipment, and voltage distortion that affects sensitive electronics. Utilities and industrial standards such as IEEE-519 place strict limits on total harmonic distortion (THD), and failing to comply can mean penalties, higher operating costs, or even restricted grid connection.

Crossman Automation helps Western Canada’s industries overcome these challenges with Low-Harmonic Drives and Active Front End (AFE) VFDs. By partnering with Danfoss, a global leader in harmonic mitigation, we provide clean-power drive solutions that reduce THD at the source, simplify compliance, and improve system reliability.

Why Harmonic Mitigation Matters

Harmonics are more than a technical nuisance—they cost real money and reliability:

  • Overheating equipment: Excessive harmonics shorten the lifespan of transformers, motors, and cables.

  • Voltage distortion: Sensitive control systems and electronics can malfunction when the supply waveform is distorted.

  • Inefficient operation: Higher system losses mean wasted energy and larger utility bills.

  • Regulatory compliance: Many facilities must meet IEEE-519 or utility-specific THD limits.

Crossman designs and supplies harmonic mitigation solutions that address these risks, ensuring your operations stay reliable and compliant.

What Are Low-Harmonic Drives?

A Low-Harmonic Drive (LHD) is a VFD engineered to generate far fewer harmonics than a conventional 6-pulse drive. Instead of relying on bulky external filters, the drive itself incorporates special rectifier technology that shapes input current into a clean sine wave.

Benefits of Low-Harmonic Drives:

  • THDi < 5–10% without additional filters.

  • Smaller footprint and simplified installation.

  • Lower wiring and commissioning costs.

  • Easier compliance with utility and IEEE-519 standards.

Example Applications:

  • Water and wastewater treatment plants.

  • HVAC systems in hospitals, data centers, and commercial buildings.

  • Industrial facilities where space and power quality are critical.

Danfoss Example: VLT® AQUA Drive Low Harmonic — purpose-built for pumping applications, delivering low THD and high efficiency in water treatment and distribution.

What Are Active Front End (AFE) VFDs?

An Active Front End (AFE) VFD is a type of low-harmonic drive that uses IGBT transistors on the input side. This topology allows the drive to actively control the shape of input current and even return excess energy back to the grid.

Benefits of AFE VFDs:

  • Ultra-low harmonic distortion across varying load conditions.

  • Near-unity power factor, improving overall system efficiency.

  • Regenerative capability—returning braking or surplus energy back to the supply.

  • Stable operation on generator power and in weak grid conditions.

Example Applications:

  • Mining, oil & gas, and heavy industry.

  • Marine and offshore systems.

  • Regenerative applications such as hoists, cranes, and elevators.

Danfoss Example: VACON® NXP AFE Drive — designed for demanding industrial applications, delivering clean power input, energy regeneration, and robust performance.

Filters vs. Low-Harmonic Drives

There are several ways to tackle harmonic distortion. Here’s how Low-Harmonic Drives compare:

Solution

Typical THDi

Pros

Cons

Passive Harmonic Filter

~10–15%

Low cost, simple to retrofit

Fixed tuning, bulky

Active Harmonic Filter

<5%

Dynamic, scalable, flexible

Higher cost, additional cabinet

Low-Harmonic / AFE Drive

<5–10%

Integrated, efficient, compact

Higher upfront cost

Crossman Automation supplies all three categories—passive filters, active filters, and low-harmonic drives—and can recommend the right option based on your system, load profile, and compliance requirements.

Danfoss Low-Harmonic Solutions Available from Crossman

We supply and support the complete Danfoss harmonic-mitigation lineup, including:

  • VLT® AQUA Drive Low Harmonic – optimized for water and wastewater pumping applications.

  • VLT® HVAC Drive Low Harmonic – delivering clean power for building systems.

  • VACON® NXP AFE Drive – high-performance AFE for mining, oil & gas, and heavy industry.

  • VLT® Advanced Harmonic Filters (AHF 005 / AHF 010) – compact passive filters that cut THDi to 5–10%.

Whether you need a compact retrofit solution or a fully integrated AFE system, Crossman ensures you get the right product for your application.

Why Choose Crossman Automation?

  • Expertise: Decades of experience in power quality, VFDs, and automation across Western Canada.

  • Compliance: Solutions designed to meet IEEE-519 and utility standards.

  • Partnerships: Direct relationship with Danfoss and other global leaders in harmonic mitigation.

  • Integration: We don’t just sell products—we engineer panels, perform harmonic studies, and support commissioning.

  • Local Support: Inventory and service from Edmonton means fast delivery and responsive assistance.

Let’s Clean Up Your Power

Don’t let harmonic distortion shorten your equipment life, waste energy, or put you out of compliance. Crossman Automation can help you design and implement the right harmonic mitigation strategy—whether that means passive filters, active filters, or low-harmonic drives with integrated AFE technology.

Contact us today to request a harmonic study or a quote on Danfoss low-harmonic drives and AFE VFDs. Together, we’ll ensure your system delivers clean power, reliable performance, and long-term savings.