Project 2 - Modeling of 3 phase Induction Motor Drive

Project 2 part 1

AIM:-

1. Model 3 Phase Inverter using Simulink (model the parasitic as well) with a switching frequency of 10Khz using 3 phase Squirrel Cage Induction motor, using V/F method, open loop

Design Parameters:

1. Power = 100 HP
2. DC Voltage = 800 V
3. Output Voltage = 460 VRMS – line to line
4. Initial Speed = 1500 RPM
5. Final Speed = 1000 RPM
6. Initial Load Torque = 10 Nm
7. Final Torque=20 Nm
8. Torque Step Time = 0.1 secs

For Induction Motor model – use Asynchronous Machine from Simulink with Squirrel Cage Preset Model – 05 , for 100HP Motor

For back emf to speed relation, assume a linear rate from 0.25 to 1, with speed changing from 500 RPM to 2000 RPM

Plot speed, stator voltage (line to line) and frequency.

Plot stator line voltage, phase current

For this project we will Consider the above paramaters and design the whole model and

simalute in Matlab simulink.

The Simulink model that we create is as follows.

In this project we are using the switch schemes for the 6 IGBT's at 15KHz , the

switching schematics are as shown below.

We are using the following torque referances .

1. Initial Load Torque = 10 Nm
2. Final Torque=20 Nm
3. Torque Step Time = 0.1 secs

Also the V/I Control mechanism of the drive is as.

Now the output waveforms like

Rotor speed

Rotor current

Electromagnetic torque

Stator current

Stator flux

Stator voltage

are shown below

Project 2 part 2

AIM:- Use the 3 phase inductor motor theory to derive the transfer function of 3 phase

Induction Motor.

To delive the Transfer function of a three phase induction motor we will proceed

as follows.

From Rotor voltages and rotor fluxes equations we have the following equation

It is possible to control the rotor flux via the stator current on the D axis. This can

be demonstrated from the rotor electric equation on the D axis and from equation Ird

above.

By substuting value of Irq in Qsq we have the following equation

The D stator voltage expression becomes:

By replacing dqr/dt in Vsd the stator voltage of the D axis can be written as follows:

the coupling between the two axes D and Q.

The whole transfer will be attached with model files at last.

Project 2 part 3

AIM:- Model 3 phase induction motor with a 3 phase inverter using Direct Torque control using an Average Model, Implement both torque and flux control to achieve desired power.

Design Parameters:

1. Initial Speed = 0 RPM
2. Flux Target = 2.5 webers
3. DC Voltage = 500 V;
4. Fundamental Frequency = 60 Hz
5. Speed Step Time = 0.01 secs
6. Determine fundamental speed based upon fundamental frequency
7. Determine the switching sequence for direct torque control
8. Moment of Inertia = 0.1 Kgm^2
9. Load Torque Initial = 0 Nm
10. Final Load Torque = 50 Nm
11. Torque Step Time = 0.03 secs

Motor Parameters: (Create an Average Model)

1. Stator Resistance = 0.5 Ohms
2. Rotor Resistance = 0.2 Ohms
3. Stator Leakage Inductance = 20 mH
4. Rotor Leakage Inductance = 10 mH
5. Magnetizing Inductance = 200 mH
6. Number of Poles = 4
7. Torque to Speed

We will built the simulink model with the above paramaters in Matlab simulink

as shown below.

Here we are using the following reference flux

Here we are using the following reference Speed

Here we are using the following reference Torque

Rotor flux

Stator flux

Speed

Torque output

All the Model files and Transfer function pdf will be attached below, please find the attachment files.