EE6200 Assignment 06
29 October 2021
A 3-ϕ Induction Motor (IM) specifications and parameters are given in Table 1 and Table 2 respectively.
Table 1: Machine Specifications
S.No
Parameter
Value
1
Power
30 kW
2
Voltage
380 V
3
Current
59 A
4
Frequency
50 hz
5
Power factor
0.88
6
Speed
1450 rpm
7
Rotor Type Squirrel cage
Rs
0.127 Ω
Table 2: Model parameters
Rr′
Lls
Llr
J
0.127 Ω 1.341 mH 1.341 mH 1.631 kg − m2
The motor is fed by a 2-level Voltage Source Inverter (VSI) based Variable Speed Drive (VSD). The drive
switching frequency is 2 kHz.
1. (a) Calculate the DC bus voltage requirement for the full speed operation of the drive and simulate the
IM in MATLAB SIMULINK for V/F control of VSI fed IM drive at no load and rated speed.
(b) If IM is driving a generator type load which is proportional to the angular speed of the motor, calculate the proportionality constant of load and simulate the V/F control of IM drive with generator
type load.
(c) A sudden full load is applied when the motor is running at full speed and no load, does any dip in
the speed is observed ? Justify your answer with proper explanation.
(d) What effects are seen in the motor speed and currents at the starting of the motor when V/F ratio
of the drive is changed to 50% of it’s rated value [speed reference = rated speed, load=0]?
1