Thyristor Voltage Controller 1w221k

EE 4183 – Laboratory Practice VI

THYRISTOR VOLTAGE CONTROLLER

Instructed by : Mr.Chirath Pathirawasam

Group :

Name

: K.T.K Perera

M.G.K Pathirana

110409X

Index No

: 110422F

K.T.K Perera

110422F

Group

: G18

H.P.C.Sirithunge

110543C

Date of Performance : 03/08/2015

P.H.D.A.S.Srimal

110555N

Date of Submission : 17/08/2015

Single Phase Half Wave Controller Output Voltage

Single Phase Full Wave Controller Output Voltage

AC Voltage Controller Output Voltage

CALCULATIONS

a) Single Phase Half Wave Controller Sample Calculation for 1st observation,

V ¿ =100 , E R =23.5 , E C =9.0

Delay Angle ( α )=2 tan−1

ER EC

( ) ¿ 2 tan−1

( 23.5 9.0 )

¿ 138.090

V Output Voltage(¿¿ L)= ¿

Vm (1+cos α ) 2π

2V ¿ √ ¿ (1+cos α ) 2π ¿

100 √ 2 (1+ cos 138.09) 2π

¿ 5.76 V

Then, Delay Angle α (degree) 138.09 135.98 132.08 126.87 120.51 111.96 98.54 83.06 60.69 24.02 0.00

Theoretical VL (V) 5.76 6.33 7.43 9.01 11.09 14.10 19.18 25.24 33.54 43.09 45.04

b) Single Phase Full Wave Controller Sample Calculation for 1st observation,

V ¿ =100 , E R =22.5 , E C =11.5

Delay Angle ( α )=2 tan−1

¿ 2 tan−1

ER EC

( )

( 22.5 11.5 )

¿ 125.860

V Output Voltage(¿¿ L)= ¿ ¿√

¿

Vm (1+ cos α ) π

2V¿ (1+cos α ) π

102 √ 2 (1+cos 125.86) π

¿ 18.66 V

Then, Delay Angle α (degree) 125.86 123.86 119.65 115.24 110.02 101.93 90.00 79.61 56.43

Theoretical VL (V) 18.66 19.95 22.76 25.83 29.62 35.73 45.04 53.16 69.94

19.32 0.00

87.54 90.08

c) AC Voltage Controller Sample Calculation for 1st observation,

V ¿ =100 , E R =22.5 , E C =11.5

Delay Angle ( α )=2 tan−1

¿ 2 tan−1

ER EC

( )

( 22.5 11.5 )

¿ 125.860 ¿ 2.2rad

V Output Voltage(¿¿ L)=V m ¿

√ √ √

¿ √ 2V ¿

¿ 100 2

√

1 α sin 2α − + 2 2π 4π

1 α sin 2 α − + 2 2π 4π 1 2.2 sin(2 x 2.2) − + 2 2π 4π

¿ 55.98V

Then, Delay Angle α

Delay Angle α

Theoretical VL (V)

(degree) 125.86 122.78 119.65 115.24 110.02 83.97 86.42 77.71 54.24 22.14 0.00

(radian) 2.20 2.14 2.09 2.01 1.92 1.46 1.51 1.36 0.95 0.39 0.00

55.98 57.46 58.92 60.93 63.23 73.61 72.70 75.90 83.91 93.77 100.00

Theoretical and Practical Output Voltage VLvs. Delay Angle α for Single Phase Half Wave Controller

Delay Angle α (degree) 138.09 135.98 132.08 126.87 120.51 111.96 98.54 83.06 60.69 24.02 0.00

Theoretical VL (V)

Practical VL (V)

5.76 6.33 7.43 9.01 11.09 14.10 19.18 25.24 33.54 43.09 45.04

3 3 3 5 7 10 13 20 28 39 43

Theoretical and Practical Output Voltage vs. Delay Angle Graph for Single Phase Half Wave Controller 50

45

40

Theoritical Output Voltage 35

Polynomial (Theoritical Output Voltage)

30

Output Voltage (V)

25

20

15 Practical Output Voltage

Polynomial (Practical Output Voltage)

10

5

0 0

20

40

60

80

100 120 140 160

Delay Angle (Degree)

Theoretical and Practical Output Voltage VLvs. Delay Angle α for Single Phase Full Wave Controller

Delay Angle α (degree) 125.86 123.86 119.65 115.24 110.02 101.93 90.00 79.61 56.43 19.32 0.00

Theoretical VL (V)

Practical VL (V)

18.66 19.95 22.76 25.83 29.62 35.73 45.04 53.16 69.94 87.54 90.08

11 12 14 17 19 24 31 40 57 80 86

Theoretical and Practical Output Voltage vs. Delay Angle Graph for Single Phase Full Wave Controller 100

90

80

Theoritical Output Voltage 70

Polynomial (Theoritical Output Voltage)

60

Output Voltage (V)

50

40

30 Practical Output Voltage

Polynomial (Practical Output Voltage)

20

10

0 0

20

40

60

80

100

Delay Angle (Degree)

120

140

Theoretical and Practical Output Voltage VLvs. Delay Angle α for AC Voltage Controller

Delay Angle α (degree) 125.86 122.78 119.65 115.24 110.02 83.97 86.42 77.71 54.24 22.14 0.00

Theoretical VL (V)

Practical VL (V)

55.98 57.46 58.92 60.93 63.23 73.61 72.70 75.90 83.91 93.77 100.00

28 30 34 40 44 50 58 72 84 96 98

Theoretical and Practical Output Voltage vs. Delay Angle Graph for AC Voltage Controller 110

100

90

80 Theoritical Output Voltage

Polynomial (Theoritical Output Voltage)

70

60

Output Voltage (V) 50

40

Practical Output Voltage 30

Polynomial (Practical Output Voltage)

20

10

0 0

20

40

60

80

100

Delay Angle (Degree)

120

140

DISCUSSION Comments on practical output voltages vs. theoretical output voltages. According to the above 3 different plotted graphs, we can observe that the output voltage across the load is decreased with the increase of delay firing angle of the thyristor. It is clear that the practical values are slightly less than that of the theoretical values. It is because we assume that the power electronic devices which we used to this practical are behave ideal devices during the theoretical calculations. But in practice, those are not real. Apart from these errors, the errors in the measuring instruments and human errors while taking readings are reasons for the deviation of theoretical and practical values. And also the voltage drop across the diodes which was there in the practical circuit was not considered during the theoretical derivation and this can be caused the deviation of practical values from the theoretical values. Give a short discussion on the application of the voltage controllers in practice Uninterruptible power supplies (UPS) One of the applications of thyristors is static transfer switch, used to improve the reliability of uninterruptible power supplies (UPS). There are two modes of using the thyristors. The 1 st mode leaves the load permanently connected to the UPS system and in case of emergency disconnects the load from the UPS and connects it directly to the power line. The 2 nd mode is opposite to the 1st one. Under normal conditions the load is permanently connected to the power line, and in event of a line outage, the load is disconnected from the power line and connected to the UPS system. Light Dimmers A light dimmer works by essentially chopping parts out of the AC voltage. This allows only part of the voltage waveform to to the lamp. The brightness of the lamp is determined by the power transferred to it, so the more the waveform is chopped the more it dims. A thyristor is a uni-directional device and hence two of them are needed to AC power to flow in both directions. An electronic circuit determines the point in time at which they turn ON and that state continuous until the next zero crossing point, at which they turn off. Transformer Tap Changing In these types of tap changers, thyristors use to hold the load while the main s change over from one tap to the next. This prevents arcing on the main s and can lead to a longer service life between maintenance activities. These tap changers have very complex design and need low voltage power supply, that can be more costly. Induction Heating The energy which es to the heater in an induction heater is controlled by a voltage regulator. In this induction heating, low frequency AC power is convert to high frequency with the use of an inverter by changing AC to DC and then again DC to AC using thyristors.

DC Motor Control For motors up to a few kilowatts the armature converter can be supplied from either single phase or three phase mains. A separate thyristor or diode rectifier is used to supply the field of the motor which the power is much less than the armature power. Variable Speed Air Compressor The most common form of VSD technology in the air compressor industry is a variable frequency drive. It converts the incoming AC power to DC and then back to a quasisinusoidal AC power using an inverter switching circuit which is consists with thyristors.