VFD

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Interactive VFD Simulation

⚡ Interactive Variable Frequency Drive (VFD) Simulation

AC Supply → Rectifier → DC Link → PWM Inverter → 3-Phase Induction Motor

1. VFD Power Conversion

AC SUPPLY 400 V / 60 Hz
→
RECTIFIER AC → DC
→
DC LINK 540 V DC
→
PWM INVERTER 4 kHz
→
3-PHASE MOTOR Induction Motor
→
MECHANICAL LOAD 50%

2. VFD Controls

READY — Press START to run the motor

3. Real-Time Motor Measurements

Frequency
0
Hz
VFD Voltage
0
V RMS
Motor Speed
0
rpm
Synchronous Speed
0
rpm
Slip
0
%
Motor Current
0
A
Torque
0
N·m
Power
0
kW
V/f Ratio
0
V/Hz

4. Motor Speed Demonstration

3-PHASE
INDUCTION
MOTOR

Increase the VFD frequency and observe the motor/fan speed increase.

5. V/f Control Demonstration

V/f = Motor Voltage ÷ Output Frequency

Below the base frequency, the VFD approximately maintains a constant voltage-to-frequency ratio.
Output Frequency
30
Hz
Output Voltage
200
V
V/f Ratio
6.67
V/Hz
Base Frequency
60
Hz

6. Oscilloscope — VFD Waveforms

Input AC Supply

Rectified DC

PWM Inverter Output

Motor Fundamental Voltage

7. PWM Demonstration

The VFD compares a sinusoidal reference with a high-frequency carrier to generate Pulse Width Modulation (PWM).

Sine Reference + Triangular Carrier

PWM Switching Pattern

PWM switching frequency: 4 kHz

8. VFD Harmonics Demonstration

The harmonic display is an educational visualization rather than a measurement of a particular commercial VFD.

9. Load and Slip Demonstration

For a 4-pole motor, synchronous speed is approximately:

Ns = 120 × f / P

Where: Ns = synchronous speed (rpm)
f = frequency (Hz)
P = number of poles = 4
Frequency Synchronous Speed Illustrative Motor Speed*
10 Hz300 rpm≈ 285 rpm
20 Hz600 rpm≈ 570 rpm
30 Hz900 rpm≈ 855 rpm
40 Hz1,200 rpm≈ 1,140 rpm
50 Hz1,500 rpm≈ 1,425 rpm
60 Hz1,800 rpm≈ 1,710 rpm

*Illustrative values. Actual induction-motor speed depends on motor design, load and slip.

10. VFD Fault Demonstration

Try this experiment:

1. Select Motor Overload.
2. Press START.
3. Increase the load toward 100%.
4. Observe motor current, speed and the fault status.

The fault behavior here is simplified for educational demonstration and does not represent the protection settings of a particular VFD.

11. Suggested Virtual Laboratory Experiment

  1. Set the frequency to 10 Hz and start the motor.
  2. Gradually increase the frequency to 60 Hz.
  3. Observe motor speed and V/f ratio.
  4. Increase the motor load from 20% to 100%.
  5. Observe current, torque, speed and slip.
  6. Change PWM frequency from 2 kHz to 12 kHz.
  7. Observe how the switching pattern changes.
  8. Enable different harmonic components.
  9. Try the fault demonstrations.