Common Bus Supply Comparison

1. Diode Bridge——non regenerative  common DC bus system

With diode bridge as supply front end, this is the lowest cost front end solution. But poor power factor & harmonic's.


2. DC791P——non regenerative  common DC bus system

While a 2Q drive as supply front end, this is the middle cost front end solution, this system can provide the supply voltage & pre-charge. But does not provide good power factor and creates harmonic distortion.



3. DC790P——regenerative  common DC bus system

3-Phase 4Q DC Drive, simple & reliable and medium cost & provides line regeneration but requires a step-up transformer, but poor power factor and harmonics. 



4. Active Front End(AFE)——regenerative  common DC bus system

ACTIVE FRONT END (AFE) AC800, reliable and provides 1.0 power factor and zero harmonic's. Provides line regeneration. Higer cost but will pay back to end customer on power cost savings. 


AC Drives have two major issues:

1.  Difficulty handling Regenerative Loads

2.  Creation of Harmonics back to AC Power Line

ETD AFE Drives solve both problems!

AC Drives and Regeneration 

How AC Drives Cause Harmonic Distortion

Harmonic Control Methods (single drive)

Regen AC Drives - for Clean Power

  • Input current comparison

  • Harmonic order comparison

The “True Unity Power Factor” Drive

The ETD 4Q AC Drive ensures that input current is always in phase with voltage, regardless of motor speed and load.


  • No PF correction needed!

  • No PF utility penalties!


Applications for Regenerative AC Drives

• Ski Lifts and Cable Cars
• Decanter Centrifuges - wastewater
• Batch Centrifuges

    - Sugar
    - Chemical
    - Pharmaceutical

• Test Stands

    - Chassis Dynamometers

• Stamping Presses
• Windmills & Windfarms
• Pumping
• Paper Mills
• Hoists & Cranes