Variable frequency drives (VFD) or variable speed drives (VSD)

Adjustable speed drive equipment is used to control the speed of machinery. Many industrial processes, such as assembly lines, must operate at different speeds according to the production needs and requirements. Where process conditions demand adjustment of flow from a pump or fan, varying the speed of the drive may save energy compared with other techniques for flow control. Variable frequency drives are also one of the best solutions for reducing machinery mechanical stress and for increasing motor life cycle.

Key systems: IGBT stack

  • Rectifier
  • Voltage-source inverter (VSI)
  • Current-source inverter (CSI)

Key components:

  • Power modules / IGBT
  • Capacitors
  • Laminated busbars for reducing line inductance
  • Inductors
  • IGBT driving systems
  • Connectors
  • Sensors

Frequent inverter topologies:

  • 2-level VSI (Voltage Source Inverter)
  • NPC (Neutral Point Clamped) multilevel inverter
  • 7-level VSI H-bridge
  • 7-level flying capacitor