Industrial Engineer · phase 8 of 16
Inverter
Output power stage that switches DC into variable-frequency, variable-voltage AC for the motor.
The Explain card
- Plain English
- The inverter is the back end of the drive. Six fast switches take the DC bus and chop it into three phases of pulses that the motor sees as AC at the commanded frequency.
- Example
- The drive commands 45 hertz. The inverter switches thousands of times a second to shape three sine like currents that complete 45 cycles every second in the motor windings.
- Why it matters
- The inverter is where the motor's voltage, frequency and current are actually made, and where most of the drive's heat and most of its expensive failures happen. An output short or a ground fault is felt first here.
- Hook
- DC goes in, a made to order three phase comes out.
Where it sits in the deck
Phase 8: VFD Drive Hardware and Power Path
Inside the drive: rectifier, DC bus and inverter, the three stages every variable frequency drive uses to rebuild the waveform a motor sees.
