Al-Najah National University Al-Najah National University Electrical Engineering Department Electrical Engineering Department Speed Drive For Three-Phase Induction Speed Drive For Three-Phase Induction Motor Motor Presentation Presentation By Eng.Mu’taz S. Al-Sheikh & Eng.Khalid Hammoudeh Supervisor Prof . Dr . Marwan Mahmmod
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Al-Najah National University Electrical Engineering Department Electrical Engineering Department Speed Drive For Three-Phase Induction Motor Presentation.
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Al-Najah National University Al-Najah National University
Electrical Engineering Department Electrical Engineering Department Electrical Engineering Department Electrical Engineering Department
Speed Drive For Three-Phase Induction MotorSpeed Drive For Three-Phase Induction Motor
Presentation Presentation
By
Eng.Mu’taz S. Al-Sheikh & Eng.Khalid Hammoudeh
Supervisor
Prof . Dr . Marwan Mahmmod
NNsyn syn = 120 f / P= 120 f / P NNsyn syn = 120 f / P= 120 f / P
Changing number of poles (P) :
Methods for drive speed of IM :Methods for drive speed of IM :
This method requires a motor with special stator winding
Changing line frequency (f) :
Changing in (f) is affect in magnetization current & flux
Ф α 1/f
Changing line voltage (v):
Changing in (v) is affect in magnetization current & flux
Ф α v
The perfect method for drive is :The perfect method for drive is : The perfect method for drive is :The perfect method for drive is :
Methods for drive speed of IM :Methods for drive speed of IM :
Changing line voltage proportional to frequency
The ratio V / f constant.
The advantages of this method clearly in:
The flux (Ф) remains constant.
The torque remains constant at any speed
under the rated speed.
Note that : this project use the fourth
method for controlling under rated speed.
Characteristic curve for V/f constant :Characteristic curve for V/f constant : Characteristic curve for V/f constant :Characteristic curve for V/f constant :
Methods for drive speed of IM :Methods for drive speed of IM :
The general categories of (VSI) inverter:The general categories of (VSI) inverter: The general categories of (VSI) inverter:The general categories of (VSI) inverter:
Square wave inverter :
Voltage source inverter (VSI) :Voltage source inverter (VSI) :
The DC voltage Is controlled in order to control the magnitude of the AC output voltage and the inverter control the frequency.
The output voltage is a square wave voltage.
Voltage source inverter (VSI) :Voltage source inverter (VSI) :
Pulse width modulation inverter (PWM) :
The DC voltage Is constant and the inverter control the magnitude of the AC output voltage and the frequency.
The behavior of one leg inverter.
To obtain any desired frequency , a sinusoidal control signal at desired frequency compared with a triangle wave .
Vcont > Vtri T+ IS ON Vcont < Vtri T- IS ON
The control wave & output wave form for three leg (PWM):The control wave & output wave form for three leg (PWM):
PWM Inverter (sequence of operation) :PWM Inverter (sequence of operation) :
Control Circuit of Project :Control Circuit of Project :
1. fFCT = 100 - 220 KHz ( results in varying output frequency from 30 to 85 Hz ) 2. fVCT = 300 KHz (results in obtaining V/f constant up to f01 =50 Hz).3. fOCT = 560KHZ (results in delay between the upper and lower transistor
operation = 0.0285 ms ). 4. fRCT = 560KHz (results in the maximum switching frequency = 2KHz )
The Results :The Results :• The minimum output frequency set to be 30Hz and the wave form of VRY is shown in fig
• The maximum output frequency set to be 85Hz and the wave form of VRY is shown in fig.
The Results :The Results :
• The 120˚ phase shift between R,Y phases :
Inverter Use in Project :Inverter Use in Project :
V / F = Constant , Showing in the table belowV / F = Constant , Showing in the table belowV / F = Constant , Showing in the table belowV / F = Constant , Showing in the table below
Measurements :Measurements :
VoltageVoltageVoltageVoltage V / F ratioV / F ratioV / F ratioV / F ratioFrequencyFrequencyFrequencyFrequency