A variable-frequency drive (VFD, or adjustable-frequency drives, adjustable-speed drives), variable-speed drives, AC drives, micro drives, inverter drives, or drives) is a type of AC motor drive (system incorporating a motor) that controls speed and torque by varying the frequency of the input electricity. Depending on its topology, it controls the associated voltage or current variation.[1][2][3][4][5]
VFDs are used in applications ranging from small appliances to large compressors.[6] Systems using VFDs can be more efficient than hydraulic systems, such as in systems with pumps and damper control for fans.[7]
Since the 1980s, power electronics technology has reduced VFD cost and size and has improved performance through advances in semiconductor switching devices, drive topologies, simulation and control techniques, and control hardware and software.
VFDs include low- and medium-voltage AC-AC and DC-AC topologies.
Keywords
type
VFDs
size
fans
pumps
1980s
torque
VFD cost
topology
software
advances
hardware
AC drives
simulation
performance
applications
micro drives
AC motor drive
damper control
inverter drives
DC-AC topologies
small appliances
drive topologies
hydraulic systems
large compressors
current variation
input electricity
associated voltage
control techniques
medium-voltage AC-AC
variable-speed drives
adjustable-speed drives
variable-frequency drive
adjustable-frequency drives
power electronics technology
semiconductor switching devices
