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Monday, June 27, 2011

EC2404 GULATION CHARACTERISTICS OF FLYBACK CONVERTER ANNA UNIVERSITY LAB MANUAL


REGULATION CHARACTERISTICS OF FLYBACK CONVERTER

EXPT NO: 2

AIM:
To determine the closed loop response of the Flyback converter and plot the regulation characteristics.

APPARATUS REQUIRED:

1.      VSMPS-09A Trainer
2.      Pulse patch chords
3.      (0-30V) DC supply
4.      CRO

FORMULA:

            Output voltage V= (D / 1-D)(N2/N1) Vs Volts

                        Where V0 =  Converter Output Voltage, Volts
                                    Vs = Converter input voltage,volts
                                    D =  Duty Cycle (tON / T)
N2 / N1 = Transformer turns ratio.

THEORY :

            The flyback converter is a negative output step-up converter (i.e) it is an isolated version of the buck-boost converter. The inductor of buck-boost converter has been replaced by a flyback transformer. The input dc source Vs and switch Q are connected in series with the transformer primary. The diode D and the RC output circuit are connected in series with the secondary of flyback transformer. The circuit diagram of flyback converter is shown below.




CIRCUIT DIAGRAM :


                         





                                                FLY BACK CONVERTER




MODEL GRAPH:










                   

    Line Regulation                                                     Load Regulation
                                                               


CONNECTION PROCEDURE :

1.      Connect P8 of PWM generator to PWM input of Flyback converter circuit.
2.      Connect P4 of Flyback converter circuit to P7 of PWM generator.
3.      Set switch SW1 to downward direction to select the closed loop operation.
4.      Connect (0-30V) DC regulated power supply across P1 and P2 terminals of the trainer module and set the voltage at 30 V.





































TABULATION:

A) Line Regulation:


                       
S.No
Input Voltage (Volts)
Output Voltage (Volts)












B) Load Regulation:

S.No
Load Resistor (W)
Load Current (mA)
Output Voltage (Volts)

























EXPERIMENTAL PROCEDURE:

A) Line Regulation:
           
1.      Switch ON the AC power supply and the power ON/OFF switch of the trainer kit.
2.      View the carrier signal in CRO at T3.
3.      Set the switch SW1 in downward direction.
4.      View the PWM signal in CRO at T1.
5.      Vary the Set voltage adjust POT from minimum to maximum and note down the ton and T values.
6.      Set the PWM signal at desired duty cycle ratio (maximum 50%).
7.      Switch ON the variable DC supply.
8.      Vary the input voltage from (0-30) V and note down the corresponding output voltage across P5 and P6 output terminals of trainer module.
9.      For each input voltage value tabulate the measured output voltage values.

b) Load Regulation:

1.      Switch ON the AC power supply and the power ON/OFF switch of the trainer kit.
2.      View the carrier signal in CRO at T3.
3.      Set the switch SW1 in downward direction.
4.      View the PWM signal in CRO at T1.
5.      Vary the Set voltage adjust POT from minimum to maximum and note down the ton and T values.
6.      Set the PWM signal at desired duty cycle ratio (maximum 50%).
7.      Switch ON the variable DC supply.
8.      Set the input to a constant value and vary the load resistor value, note down the corresponding output voltage across P5 and P6 output terminals of trainer module..
9.      For each load resistor value tabulate the measured output voltage values.


RESULT:

            Thus the closed loop response of flyback converter of Line/Load regulation was determined.
1.      The output voltage is maintained at ------ V with the input voltage from   ------- V to ---------- V.
            

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