The Impact of Variable Frequency Drives (Frequency Inverters) (part 9)
Continued from this article: The Impact of Variable Frequency Drives (Frequency Inverters) (part 8).
Generally the higher the carrier frequency, the closer the output waveform of VFD is to a pure sine-wave.
One method of reducing motor noise is full-spectrum switching. Drive manufacturers accomplish full-spectrum switching by an algorithm within the drive regulator. The algorithm optimizes motor performance by evaluating motor characteristics, including motor current, voltage and the desired output frequency. The resulting frequency band, though audible to humans, produces a family of tones across a wide frequency band. Thus the perceived motor noise is considerably less than it would be with a single carrier frequency.
Of course, the motor noise may not present a problem at your facility. Relevant factors include motor locations and the amount of noise produced by other equipment. In most cases, engineers can reduce motor noise by either adjusting the variable frequency drive (VFD) controller or redesigning the motor and the controller installation configuration, for example, by adding a reactor betwwen the VFD and the motor. Newer generation drives and motors minimize annoying motor noise. (to be continued)
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You may be interested in reading this: Applications Considerations While Appling Frequency Inverter (VFD)
Know more about VFD technology: Overview of variable frequency drive technology
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