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# Fuzzy Based Scalar Control of Induction Motor

Fuzzy Based Scalar Control of Induction Motor

The Simulink model developed for fuzzy logic-based control of scalar control of an induction motor consists of the following elements:

• DC source

• Voltage source inverter

• Induction motor

Here, we are using fuzzy logic-based speed control as well as PID speed control.

The key steps are as follows:

1. Speed Measurement:

• The speed of the induction motor is measured in radians per second.

• It is then converted to revolutions per minute (RPM) by multiplying it by 602Ï€\frac{60}{2\pi}2Ï€60â€‹.

1. Feedback and Error Calculation:

• The measured speed is fed back and combined with the reference speed to calculate the error and rate of change of error.

• These values are inputs for the fuzzy logic controller.

1. Fuzzy Logic Controller Output:

• The output of the fuzzy logic controller is the slip speed (Ï‰sl\omega_{sl}Ï‰slâ€‹).

• The slip speed is added to the actual speed of the induction motor to provide the speed that needs to be maintained.

1. Frequency and Amplitude Calculation:

• The calculated speed is converted into frequency using the formula f=PÃ—Ï‰120f = \frac{P \times \omega}{120}f=120PÃ—Ï‰â€‹.

• This frequency is converted into amplitude and used to generate a three-phase sinusoidal waveform as a reference.

1. Pulse Generation:

• The reference voltage frequency signal is compared with a triangular wave to generate pulses for the voltage source inverter, controlling the induction motor.

### Simulation Results with PID Control

First, we simulate the model using a PID controller with the following reference speed changes:

• Initially set to 1500 RPM.

• Changed to 1000 RPM after 5 seconds.

The response of the induction motor with PID control is as follows:

• There is an overshoot and undershoot in the speed response.

• It takes around 3 seconds to reach the initial reference speed of 1500 RPM.

• After the speed change to 1000 RPM, it takes around 1.5 seconds to settle to the new reference speed.

### Simulation Results with Fuzzy Logic Control

Next, we simulate the same model using a fuzzy logic-based controller.

The response of the induction motor with fuzzy logic control is:

• The speed response is very smooth without overshoot or undershoot.

• It reaches the reference speed of 1500 RPM in about 1.25 seconds.

• After the reference speed changes to 1000 RPM, it quickly settles to the new speed in about 0.3 seconds.

### Comparison of PID and Fuzzy Logic Control

When comparing the PID and fuzzy logic controllers:

• The PID controller exhibits overshoot and undershoot, taking longer to reach the reference speed.

• The fuzzy logic controller provides a smooth response, reaching the reference speed quickly without overshoot or undershoot.

### Conclusion

The fuzzy logic-based scalar control has a better response compared to the PID controller. It quickly tracks the reference speed command and provides a smoother operation.