lab 1 DJM40103

DJM40103 – POWER ELECTRONIC
PRACTICAL WORK 1 - SINGLE-PHASE CONVERTER WITH

RESISTIVE LOAD

Objectives:
• Voltage and current measurements
• Observe the output and input waveform
• Compare the output waveform using various triggering angle.
• Obtain the SCR current at triggering angle 90°

Equipments:
• 1 DL 2604 SCR
• 1 DL 2613 Dc power supply
• 1 DL 2614 Voltage reference generator
• I DL 2616 Two pulse control unit
• 1 DL 2626 Mains transformer
• 1 DL 2628 Super-fast fuses (3x6.3 A)
• 1 DL 2635 Universal load
• 1 DL 2643 Socket with shunts 1 ohm
• 1 DL 2109T3PV Moving-iron voltmeter (125-250-500 V)
• 1 DL 2109T33 True rms meter
• 1 Dual-channel oscilloscope (preferred storage type)

Theory:

 For the positive half cycle of input voltage, the thyristor T1 is forward biased and
when the thyristor is fired at wt = α , it conducts and the input voltage appears across
the load.

 When the input voltage goes negative at wt = π, the thyristor is reversed biased and it
is turned off.

 The delay angle α, is defined as the time the input voltage starts to go positive to the
time the thyristor is fired.

a) circuit single-phase converter with resistive load b)

 The average output voltage Vdc and the average output current is given by:

Vdc  1 T vL (t)dt
T 0

VL (t)  0 for  t  T

Vdc  1  sin(t)dt  Vm  cos(t )
T T 
Vm



Vdc  Vm  cos(t )   Vm 1 cos 
2  2

Vdc  Vm 1  cos 
2

I dc  Vdc
R

 The rms output voltage and current is given by:

1

1 T vL2  2
T  
Vrms  (t)dt 

1

 1 T sin t2 2
Vrms   2 dt 
T
Vm 



11

 1 T 2 Vm 2 T 2
 2 sin2 tdt  T dt 
21 cos 2t
Vm 2  2 


  
T

1

 V4m2    1 sin 2  2
 2 

1

 Vm 1    1 sin 2  2
2   2

1

 Vm 1    1 2  2
2R   2
I rms sin

Circuit Diagram

7. Top
6. 9.
8.

13. 14.

ographic diagram
10.

11.
12.

15. 16.

Experiment procedure:
Assemble the circuit according with the foregoing topographic diagram, disregarding detail (a) at
first.

1) Connections

Connect the voltage reference generator DL 2614 and the control unit DL26 16 to the power
supply +15V/0/-15V.

Connect the output UO of voltage generator to input Uc of the control unit.
Connect the terminals L/N (USYN) of the control unit respectively to terminals 2V1/2V3 of the
mains transformer.

Connect the pulse transformer 4 to gate/cathode circuit of the SCR: socket marked with a dot to
the gate.

2) Basic settings

2.1) Voltage reference generator DL 2614

EXT/INT switch on INT position.

(0/+10 V)/(0/±10 V) switch on (0/+10 V) position.

Set point potentiometer to 10 V.

2.2) Control unit DL 2616.
Control angle α O switch on 00 position.
“Pulse shape” switch on single pulse position.

Inhibit voltage UINH = 15 V (open).

3) Voltage and current measurements Supply the circuit and measure:

3.1) the rms value Uv of the supply voltage by the voltmeter P1;

3.2) the average value UdAV and the rms value UdRMS of the direct voltage by the
voltmeter P2;

3.3) the average value I dAV and the rms value IdRMS of the direct current by the

ammeter P3. Enter the measured value as a function of the gate angle α in 300 steps

between 00 and 1800 in the following table.

HINT

In order to set the gate angle, set only a half-wave of the direct voltage with the width of 9

(or 6) grid divisions on the oscilloscope: each division then corresponds to an angle of 20°

(or 30°).

Another system is the use of phase shift αο in the control unit:
1) Set αο = 00 and Uc = 10 V to obtain the firing angle αο = 00 and carry out the measurements.
2) Set now αο =30° to obtain the firing angle αο = 30° and, for example, note down the IdRMS30
value.
3) Set again αο =00 and adjust Uc in order to obtain IdRMS30 and now set again αο = 300 in order to
obtain the firing angle αο = 60°: note down IdRMS60.
4) Set again αο = 0°and adjust Uc in order to obtain IdRMS60 and now set again αο = 30° in order to
obtain the firing angle αο = 90° and so on.

Input Voltage, Uv= ___________ V
α(0) 0 30 60 90 120 150 180

UdAVα (V)

UdRMSα (V)

I dAVα (A)

IdRMSα (A)

5) Recording on the oscilloscope
5.1)Recording the supply Uv, and direct Ud voltages.
Oscilloscope setting
DC coupling; Yt mode. Trigger: AC Line.
Channel 1 (voltage Uv,): 50 V/div; probe xl0.
Channel 2 (voltage Ud): 50 V/div; probe xl0.
Oscillogram (α = 900)

5.2) Recording
the diode voltage Uv and the direct current Id Oscilloscope setting.

Assemble the measuring circuit according with detail (a).

Channel I (Uv voltage): 50 V/div; probe xl0.

Channel 2 (current Id proportional to voltage at shunt Rs = 1 ): 1 V/div; probe x1.
Oscillogram (α = 900)

Conclusion: