EX NO:

DATE:SIMULATION OF SINGLE PHASE FULLY CONTROLLED CONVERTER WITH R AND RL-LOAD

AIM:

To study the performance of single phase fully controlled converter with R and

RL- load using Ramp Firing Scheme.

REQUIREMENTS:

1. MATLAB Software (version 7.6)2. PC

SPECIFICATION PARAMETERS:

1. Load Resistance(RL)

2. Load Inductance(L)

3. Input Voltage(VIN)

4. Control Voltage (VC)

5. Frequency(Hz)

BLOCK DIAGRAM:

R-LOAD:

Fig (a). Block Diagram of Single phase Fully Controlled Converter of R-Load

RL-LOAD:

Fig (b). Block Diagram of Single phase Fully Controlled Converter of RL-Load

SIMULINK BLOCK DIAGRAM:

1. R Load:

Continuous

powergui

v

+

-

Voltage Measurement2

v+ -

Voltage Measurement1 gm

ak

Thyristor4

gm

ak

Thyristor3

gm

ak

Thyristor2

gm

ak

Thyristor1

In1

Out1

Out2

Out3

Subsystem1

Series RLC Branch

Scope

I n Mean

Mean Value1

I n Mean

Mean Value

4.728

Display1

0.2364

Display

i+

-

Current Measurement

0.5

Constant

AC Voltage Source

Fig (c). Simulation Diagram of Single phase Fully Controlled Converter of R-

Load

2. RL-Load:

Continuous

powergui

v

+

-

Voltage Measurement2

v+ -

Voltage Measurement1 gm

ak

Thyristor4

gm

ak

Thyristor3

gm

ak

Thyristor2

gm

ak

Thyristor1

In1

Out1

Out2

Out3

Subsystem1

Series RLC Branch

Scope

I n Mean

Mean Value1

I n Mean

Mean Value

4.728

Display1

0.2364

Display

i+

-

Current Measurement

0.5

Constant

AC Voltage Source

Fig (d). Simulation Diagram of Single phase Fully Controlled Converter of RL-

Load

PROCEDURE:

1. Select mat lab Version 7.6 software program and choose New-Model-File.

2. After selecting model-file connect the circuit as per system design

problem.

3. After making model-file program debug the program by using run option

from debug toolbar.

4. Then observe the results for Model-file program in scope.

5. Stop Simulation.

THEORY:

The single phase fully controlled converter have R&R-L load is a

continuous mode operation it operates the T1&T2 conducting state and

T3&T4 is off state during Positive half cycle . T3&T4 are conducting

T3&T4 are conducting T1&T2 is Off state during negative half cycle by

applying gate triggering pulse.

Fully controlled R-L load it having the continuous & discontinuous modes

operation. Same operation for continuous & discontinuous the discontinuous β

is produced. The 0<90 phase shift it acts as a Rectifier mode. 0>90

phase shift it acts as an Inverter Mode . Fully controlled acts as two mode

operation.

The circuit arrangement of a single-phase full converter is shown fig.

with a highly inductive load so that the load current is continuous and

ripple free. During the positive half cycle thyristors T1 and T2 are

forward biased; and when these two thyristors are fired simultaneously

at wt= α ,the load is connected to the input supply through T1 and T2.

Due to the inductive load, thyristor T1 and T2 continue to conduct

beyond wt= π , even though the input voltage is already negative. During

the negative half cycle of input voltage, Thyristors T3 and T4 are

forward biased; and firing of thyristors T3 and T4 applies the supply

voltage across thyristors T1 and T2 as reverse blocking voltage. T1 and

T2 are turned off due to the line or natural commutation and the load

current is transferred from T1 and T2 to T3 and T4.

During the period from “α to π”, the input voltage Vs and input

current İs are positive; and the power flows from the supply to the

load. The converter is said to be operated in rectification mode. During

the period from “π to π+α”, the input voltage Vs is negative and the

input current İs is positive; and reverse power flows from the load to

the supply . The converter is said to be operated in inversion mode.

This converter is extensively used in industrial applications up to 15kw.

Depending on the value of α , the avg output voltage could be either

positive or negative and it provides two quadrant operation.

SIMULATION OUTPUT WAVE FORMS:R-LOAD

Fig(a):Supply voltage wave form.

Fig(b):Gate firing pulses

Fig(c):Gate firing pulses

Fig(d):Output voltage wave form

Fig(e):output current wave form

R-L LOAD: DISCONTINUOUS WAVE FORMS

Fig(f):Supply voltage wave form.

Fig(g):Gate firing pulse.

Fig(h):Gate firing pulse.

Fig(i):Output wave form.

Fig(j):Output Discontinuous current waveform

R-L LOAD:

R-L LOAD: CONTINUOUS WAVE FORMS

Fig(k):Supply voltage wave form.

Fig(l):Gate firing pulse.

Fig(m):Gate firing pulse.

Fig(n):Output voltage waveform

Fig(o):Output continuous wave form

THEORETICAL CALCULATIONS:

Average output voltage: Vdc=2Vm/π Cosα

And Vdc can be varied from 2Vm/π to -2Vm/π by varying α from 0 to π .The

maximum avg output voltage is Vim=2Vm/π

And the normalized avg output voltage is Vn=Vdc/Vdm=Cosα

The rms value of the output voltage is given by

VmSin2wtd(wt)]1/2=Vm/2 = Vs

With a purely resistive load, thyristors T1 and T2 conduct from α to π, and

thyristor T3 and T4 can conduct from α+π to 2π .

TABULAR FORM:

S NO

Vc

FIRING ANGLE

Vavg THEORETICAL

SIMULATED Vavg

RESULT: