PROJECT REPORT FOR COMPLETION OF

B. TECH. IN ELECTRICAL ENGINEERING

Under West Bengal University of Technology (U. Tech.)

Year : 2005-2006

Name of the Project : PWM based Inverter fed Induction Motor

Submitted by –

Group Workers Roll No. University Roll No.

Abhra Ray 12003 12716021007Amit Nag 12004 12716021008Arijit De 12007 12716021004Arijit Dey 12008 12716021047Arkendu Mitra 12010 12716021011Ayanava Chatterjee 12012 12716021013Kunal Pahari 12022 12716021046Mainak Dey 12024 12716021021Soumya Subhra Niyogi 12042 12716021031Saurav Paul 12043 12716021048Subrata Sinha Roy 12050 12716021051

This project is done under the guidance of Mrs. Shilpi Bhattacharya

81, Nilgunj RoadAgarpara, Pin - 700109

Acknowledgement

We, the student of Electrical Engineering, Narula Institute of Technology, 81 Nilgunj Road, Kolkata – 700109, have completed our project successfully under the guidance of Mrs. Shilpi Bhattacharya, Lecturer, Department of Electrical Engineering, Narula Institute of Technology, Agarpara, without whose guidance, advice, interest, encouragement and also disbursement of money for purchasing the components at proper time, our project could not have achieved its grand success. We also express our respect and profound sense of gratitude to Prof. Amlan Chakrabarti, Head of the Department, Electrical Engineering, Narula Institute of Technology, Agarpara for his moral encouragement and advisement at different stages to build up our project.

At last, we will thankful endlessly to the respective personality, Prof. Biswarup Basak, Department of Electrical Engineering, Bengal Engineering & Science University, Shibpur, who spent his expensive time to illustrate how the project circuitry can be developed.

NAME ROLL UNIVERSITY ROLL NO.

Abhra Ray 12003 12716021007 Amit Nag 12004 12716021008 Arijit De 12007 12716021004 Arijit Dey 12008 12716021047 Arkendu Mitra 12010 12716021011 Ayanava Chatterjee 12012 12716021013 Kunal Pahari 12022 12716021046 Mainak Dey 12024 12716021021 Soumya Subhra Neyogi 12042 12716021031 Saurav Paul 12043 12716021048 Subrata Sinha Roy 12050 12716021051

ContentsTopic Page No.

Introduction to Pulse Width Modulation (PWM) 11. Objective 22. Speed Control of Induction Motors 2

2.1 Pole Changing 22.2 Stator Voltage Control 42.3 Supply Frequency Control 4

3. Advantages of Frequency Control 54. Advantage and Disadvantage of PWM 6

4.1 Advantage 64.2 Disadvantage 6

5. Industrial Applications of PWM 66. Overview of the Project 7

6.1 Controlling Part 76.2 Power Part 76.3 Loading Part 7

7. Components 88. Tools and Instruments 9

8.1 For Testing Purpose 98.2 For Final Project Circuitry 9

9. Bolck Diagram of the Whole Project 1010. Total Project Circuitry 1111. Project Details 12

11.1 Controlling Part 1211.2 Power Part 24

11.2.1 Supply Part 2411.2.2 Inverter Bridge Part 24

11.3 Loading Part 2512. Test Tools 2713. Test Procedure 2714. Test Results 2715. Precautions 2816. Inference 28

1

Introduction to Pulse Width Modulation (PWM)

In this technique several pulses are produced in each half – cycle but the width of the pulses is not the same as in case of multiple – pulse width modulation, however the width of each pulse is varied in accordance with the amplitude of the sine wave reference voltage. The width of the pulse at the center of the half – cycle is maximum and decreases on either side. The figure 6(a) shows the generation of the output signal by comparing a sinusoidal reference signal fr with a triangular carrier wave of frequency fc. The carrier and reference waves are mixed in a comparator and when sinusoidal wave of has a higher magnitude than the triangular wave the comparator output is high, otherwise it is low. This output of comparator is used to turn on the MOSFETs in the bridge configuration of Figure 6(b), which generates the output voltage. The reference signal frequency fr determines the output frequency fo of the inverter, and its peak amplitude Ar, controls the modulation index M, and thereby the rms output voltage vo. Thus varying the amplitude of the sine wave within the range of zero to Vp, where Vp is the peak of the triangular wave, controls the output voltage. The number of pulses in each half – cycle depends on the carrier frequency. If the ratio of these two signals (reference and carrier) is equal to m, then the number of pulses in each half – cycle is (m - 1).

(a) (b)

(c)

Fig. – 1 Sinusoidal Pulse Width Modulation

(a) Single Phase bridge inverter (b) Gate signal voltage and (c) Output Voltage

2

1. Objective :

To vary the speed of a single phase squirrel-cage induction motor by varying supple frequency with the help of Pulse Width Modulator (PWM) based Inverter.

(Note: to change the frequency we change the resistance of controlling circuit.)

2. Speed Control of Induction Motors :

Induction motors are of two types - Squirrel-cage motor and Wound-rotor motor. There are various types of speed control methods of induction motor. These are –

(i) Pole Changing, (ii) Stator Voltage Control, (iii) Supply Frequency Control, (iv) Eddy-current Coupling, (v) Rotor Resistance Control, (vi) Slip Power Recovery. (i) is applicable for squirrel-cage motor, (ii) to (iv) is applicable for both wound-rotor and

squirrel-cage motor and (v) and (vi) is applicable for wound-rotor.For squirrel-cage type motor, here pole changing, stator voltage control and supply frequency

control methods are discussed.

2.1 Pole Changing :

For a given frequency speed is inversely proportional to number of poles. Synchronous speed, and therefore, motor speed can be changed by changing the number of poles. Provision for changing of number of poles has to be incorporated at the manufacturing stage and such a machine is called “pole changing motor” or “multi-speed motor”.

In squirrel cage motor the number of poles are same as the Stator winding. So there is no provision for changing the number of poles. But for wound rotor arrangement for changing the number of poles in rotor is required, which complicates the machine. So it is only used for Squirrel cage induction motor.

A simple but expensive arrangement for changing number of stator poles is to use two separate winding which are wound for two different pole numbers. An economical and common alternative is to use single stator winding divided into few coil groups. Changing the connections of these coil groups change number of poles. Theoretically by dividing winding into a number of coil group and bringing out terminals of these group a number of arrangements of different pole numbers is obtained.

Fig. – 2 Stator phase connection for 6-poles

Figure 2(a) above shows a phase winding consisting of six coils divided into two groups – a-b consisting of odd number coils (1, 3,5) connected in series and c-d consisting even numbered coils (2,4,6)

3connected in series. The coils can be made to carry currents in the given directions by connecting coil groups either in series or parallel as shown in figure B and C. With this connection machine has six poles. If the current through the coil group a-b is reversed [Fig. 3(a)], then all coils will produce north poles. Fluxes coming out of the north poles will now find paths through Interpol spaces for going out consequently producing south poles in Interpol spaces. The machine will now have 12 poles. Here again the direction of current through coils can be obtained by connecting two sections a-b and c-d either in series or parallel for both pole numbers 6 and 12.

Fig. – 3 Stator phase connection for 12-poles

Further three phases of the machine can be connected to form delta or star connection by choosing a suitable combination of series and parallel connection between coil groups of each phase, and star and delta connection in each phase, speed change can be obtained with constant power or variable torque operation. Connections and speed-torque curves for these operations are shown in Figs. 4 to 6.

Fig. – 4 Constant torque control

Fig. – 5 Constant power control

4

Fig. – 6 Variable torque control

2.2 Stator Voltage Control :

This is a slip control method with constant frequency variable voltage being supplied to the motor stator. Obviously the voltage should only be reduced below the rated value. For a motor operating at full load slip, if the slip is to be doubled for constant load torque then the voltage must be reduced by a factor

of and the corresponding current rises to of the full load value. The motor, therefore, tends to get

overheated. The method therefore is not suitable for speed control. It has a limited use for motor driving fan type load whose torque requirement is proportional to the square of speed. It is a commonly used method for ceiling fans driven by single-phase induction motors that have large standstill impedance limiting the current drawn by the stator.

2.3 Supply Frequency Control :

Synchronous speed .

And, motor speed, .Now, it is evident that varying synchronous speed, which can vary by varying the supply

frequency, can vary the motor speed. Voltage induced in stator is proportional to the product of supply frequency and air-gap flux .

If stator drop is neglected, then E is equal to V. Then the supply voltage will become proportional to

and .

Any reduction in the supply frequency keeping the supply voltage constant causes the increase

of air-gap flux . Induction motors designed to operate at the knee point of the magnetization characteristic to make a full use of magnetic material. Therefore, the increase in flux will saturate the motor. This will increase the magnetizing current and distort the line current and voltage, increase in core loss and stator loss and produce a high-pitch acoustic noise. Also, a decrease in flux is also avoided to retain the torque capability of motor. Therefore, variable frequency control below rated frequency is

generally carried out at rated air gap flux by varying supply voltage with frequency so as to maintain

ratio constant at the rated value.

5

3. Advantages of Frequency Control :

The variable frequency control provide good running and transient performance due to the following features –

(i) Speed control and breaking operation are possible from zero speed to base speed.(ii) During transient the operation can be carried out at the maximum torque with reduce

current giving good dynamic response(iii) Copper losses are low and the efficiency and power factor are high.(iv) Drop speed from no load to full load is small.The most important advantage of variable frequency control is that it allows a variable speed

drive with above mentioned good running and transient performance to be obtained from a squirrel cage induction motor. The squirrel cage motor has a number of advantages over a DC motor. It is cheap, rugged and long lasting. Because of absence of commutator and brushes it requires practically no maintenance; it can be operated in an explosive and contaminated environment, and can be designed for higher speeds, voltages and power ratings. Though the cost of induction motor is lesser than DC motor of same power rating but still the cost of variable frequency drive are higher in general. But because of the advantages listed above the induction motor drives of variable frequency type is mostly preferable over DC motor drives. Because of the above advantages we are dealing with this type of speed control for controlling induction motor that has a large number of industrial applications as follows –

(i) It can be used for any type of underground and underwater installation.(ii) In applications involving explosive and contaminated environment(iii) In application in tractions, steel mills, pumps, fans, blowers, compressors, spindle drivers

etc.

6

4. Advantage and Disadvantage of PWM :4.1 Advantage :

Load efficiency is almost always a critical factor in renewable energy systems. An additional advantage of pulse width modulation is that the pulses are at the full supply voltage and will produce more torque in a motor by being able to overcome the internal motor resistances more easily. A resistive speed control will present a reduced voltage to the load, which can cause stalling in motor applications. Finally, in a PWM circuit, common small potentiometers may be used to control a wide variety of loads, whereas large and expensive high power variable resistors are needed for resistive controllers.

4.2 Disadvantage :

The main disadvantages of PWM circuits are the added complexity and the possibility of generating radio frequency interference (RFI). Locating the controller near the load, using short leads, and in some cases, using additional filtering on the power supply leads, may minimize RFI.

5. Industrial Applications of PWM :

PWM A.C. drive is very popular in industry. By controlling the speed of the induction motor, production can be varied as needed. The industries that use PWM drive are

1. Water plant.2. Conveyer belt.3. Lift.

Etc.

7

6. Overview of the Project :

Basically the speed of a “single phase permanent capacitor squirrel-cage induction motor” which is fed from a PWM based inverter circuit, is controlled. The entire circuit is divided into three parts,

6.1 Controlling Part :

To control the speed of the induction machine a control circuit is made. There a sinusoidal pulse and a triangular pulse is generated separately and then compare these pulses by comparator and get triggering pulse to trigger the PWM based inverter circuit. Here sinusoidal pulse is the supply pulse of controlling network and triangular pulse is the carrier pulse of network. To vary the frequency, just vary the external resistance of the sinusoidal circuit through POT.

6.2 Power Part :

For power part a D.C. supply of 220V is used. This D.C. supply is inverted to A.C. by PWM based inverter. Though this converted A.C. is not an exact sinusoidal response by taking consideration of harmonics we get sinusoidal pulse.

PWM based Inverter circuit (Pulse Width Modulation inverter) is used for frequency control technique.

Inverter circuit consists of power transistors or power MOSFETs (depending upon the rating of the machine). These power transistors or power MOSFETs are needed to be triggered and that triggering pulse is sending from the control circuit. The variable frequency helps to vary the timing of trigger of inverter, which varies the frequency of the supply of induction machine.

6.3 Loading Part :

In the loading part single-phase squirrel cage permanent capacitor induction motor is loading where single-phase line enters, produce air-gap flux and help to run the motor.

Sl. No. Components Industrial SpecificationName Character in Project

1. OPAMP (741) It is the heart of the project. By using this we produce controlling pulses (comparing sinusoidal & triangular).

Given in data sheet.

2. GATE(7405, 7408)

It is used to design the comparator circuit. 75LS05N known as Logic inverter is used to invert the square pulse of 50 Hz. Then 75LS08N known as Logic AND Gate is used to ANDing the square pulse with the output of the OPAMP in which sine wave and triangular carrier pulse is compared.

Given in data sheet.

3. OPTO-COUPLER(MCT2E)

To isolate the triggering pulses for buffering and then for sending to the inverter circuit.

Given in data sheet.

4. POWER MOSFET(IRF720)

We use to build inverter bridge by which we invert the DC voltage into AC voltage by using gate pulse.

Given in data sheet.

5. RESISTOR To build controlling circuit we use external resistor of different specification, sometimes for getting desired time constant and sometimes for getting different gain for opamp output.

5. POT It is variable resistance which is used to change frequency & leveling the pulses over a base line.

47.5 k, 2 M

6. CAPACITOR To generate sinusoidal and triangular pulse using opamp, capacitor charging and discharging phenomena is used from which we get square wave and then by using second order low-pass filter and integrator we get sinusoidal and triangular wave.

10 nF, 100 nF.

8

7. Components :

9

8. Tools and Instruments :

8.1 For Testing Purpose :

Sl. No.

Description of Tools and Instruments QuantityName Use

1. Bread Board The whole circuit design is done on this board. In this board middle holes are on vertically same potential and up and down holes are on horizontally same potential.

4

2. Hook up wire These wires do the whole circuit design. As required

3. Cutter To remove insulation at the ends of the wires cutter is used.

1

4. Plus It is used to straight the wire; also remove the broken wires from bread board.

1

8.2 For Final Project Circuitry :

Sl. No.

Description of Tools and Instruments QuantityName Use

1. Vero Board It is used to represent the final project circuit by shouldering.

4

2. Multi-Stripped Wire

It is used to connect the component of the circuit by shouldering.

As required

3. Cutter To use wire we have to remove insulation at the ends by cutter.

1

4. Plus It is used to straight the wire; also remove the broken wires from Vero board.

1

5. Solder Iron and Solder Alloy

It is used to design the circuit on Vero Board permanently.

1

10

9. Block Diagram of the Whole Project :

Second order Inverter

Low pass filter

Integrator

Pulse Pulse

+

D.C. - -

Motor

Square wave(variable

frequency)

Sine Wave (variable

frequency)

Inverted Sine Wave (variable

frequency)

Square wave(5 kHz)

Triangular Wave

(5 kHz)

Comparator Comparator

Logic AND

Logic AND

Logic Inverter

Opto-Isolator

Opto-Isolator

1 2 3 4Inverter

BLOCK

DIAGRAM

11

10. Total Project Circuitry :

12

11. Project Details :

There are three parts in the total project circuitry, they are as follows –

11.1 Controlling Part :

At first a square wave of 50 Hz is generated by an OP-AMP. Here a POT of value 2 M is used to vary the frequency of the square wave above 50 Hz. The necessary circuit arrangement and its output are given below –

(a)

(b)

Fig. – 7 Square Wave Generator

(a) Required Circuitry and (b) Output Waveform13

Then the square wave is filtered through a second-order low pass filter made by another OP-AMP to generate the required sine wave of 50 Hz. To vary the frequency of sine wave, just vary the frequency of square wave through the POT. The function of the second-order low pass filter with an OP-AMP is describe below –

The schematic diagram of a second order low-pass filter is shown below -

Fig. – 8 Second order Low-pass Filter

The transfer function will be given by –

where K = 2, = , Q = 1.

The second-order low pass filter with specified components and its output is given in Fig. –

14

(a)

(b)

Fig. – 9 Second order Low-pass Filter

(a) Circuitry with specified components and (b) Output Waveform

Now with the help of another OP-AMP, an inverting amplifier (described below) is made, which inverts the sine wave at a phase shift 180°. Here another POT of value 50 k is used to maintain the same level of two sine waves (actual and inverted).

The connection method for producing the inverted gain using OP-AMP is called inverting amplifier. The OP-AMP makes use of single resistor (r1) and a single feedback resistor (r2). The inverting amplifier produces a phase shift of 180° in voltage from input to output. Thus the input and output signals of the inverting amplifier are not in phase with each other.

We know that OP-AMP gain without any feedback is very high. This means that the voltage at the inverting terminal must be small. As a matter of fact, the input voltage at the inverting terminal will be very nearly at the same potential as the non-inverting terminal. Now since the non-inverting input is

15grounded, the inverting input of an OP-AMP is also at the ground potential and is referred to as virtual ground.

Fig. – 10 Inverting Amplifier

Now recall that voltage gain (Av) of an amplifier is defined as the ratio of output voltage to the input voltage.Mathematically, voltage gain

The inverting amplifier circuit with specified components and its output is given in Fig. –

(a)

16

(b)

Fig. – 11 Inverting Amplifier

(a) Required Circuitry and (b) Output Waveform (inverted sine wave)

After adjusting the level of two sine waves by the POT 50 k, the obtained output is as below –

Fig. – 12 Two variable Sine Waves (actual and inverted) in a same oscilloscope

Thereafter another square wave of fixed frequency (about 5 kHz) is generated. The necessary circuit arrangement and its output are given below –

17

(a)

(b)

Fig. – 13 High Frequency Square Wave Generator

(a) Required Circuitry and (b) Output Waveform

Integrating this high frequency square wave, the triangular wave (also called carrier signal) is generated. The description of integrator circuit with an OP-AMP is as follows –

Integrator is a circuit whose output is proportional to the area of its input waveform. The RC circuit itself acts as a simple integrator. But the problem with such a simple circuit is that the output voltage is not a linear triangular output as it should be. The function of the OP-AMP is to linearize the output. It may be noted from the diagram that the inverting input to the OP-AMP is held at virtual ground by the differential amplifier in the OP-AMP input circuit.

18

Fig. – 14 Integrator

The second-order low pass filter with specified components and its output is given in Fig. –

(a)

(b)

Fig. – 15 Integrator circuit with specified components

(a) Required Circuitry and (b) Output Waveform

19Now two sine waves (actual and inverted) and the triangular wave (carrier signal) are compared

using two OP-AMPs. The comparator circuit using OP-AMP is as follows –The comparator is a circuit that is used to compare two voltages and provide an output indicating

the relationship between two voltages. Generally speaking, comparators are used to compare either,(i) Two changing voltages to each other, as comparing two sine waves.(ii) A changing voltage to a set D.C. reference voltage.Figure shows the circuit of an OP-AMP comparator. It may be noted that there is no feedback path in the circuit. In this circuit the sine wave (actual and inverted) is applied to the inverting input terminal and high frequency triangular carrier signal is applied to the inverting terminal of the OP-AMP.

Fig. – 16 Comparator

The simulation circuit and its outputs are given below –

(a)

20

(b)

(c)

Fig. – 17 Comparator circuit with specified component

(a) Required Circuitry, (b) Output Waveform of Comparator – Iand (c) Output Waveform of Comparator – II

At last the output of the first comparator is ANDed with the square wave of variable frequency by using chip 7408 and the output of the second comparator is ANDed with the inverted square wave of variable frequency (inverted by using logic inverter 7404) to generate the triggering pulse for triggering the POWER MOSFETs. The simulation circuit of ANDing and its outputs are given in the figure below –

21

(a)

(b)

Fig. – 18 ANDing the output of Comparator – I and II with Variable Square Wave

(a) Required Circuitry and (b) Output Pulses

The pulses are isolated trough four opto-couplers, so that each POWER MOSFET of the inverter bridge is being triggered separately. The opto-couplers connections and the outputs of four opto couplers, i.e., individual triggering pulses for each MOEFET are shown in Figs. below –

22

(a)

(b)

23

(c)

(d)

(e)

Fig. – 19 Separation of Pulses with Opto-isolators

(a) Opto-isolator connection and

(b) – (e) Four separate Pulses to trigger the MOSFET 1 – MOSFET 424

11.2 Power Part :

To run a motor we need voltage supply. In speed variation of single phase induction motor by varying frequency variation method we have to vary external resistance of the control part of the control circuit to vary frequency of the supply of motor.

The power part consists of two parts,(i) Supply Voltage Part.(ii) Inverter Bridge Part.

11.2.1 Supply Part :

In supply part, 230 V A.C. is required for the motor. To obtain this voltage, the value of required D.C. voltage we can obtain by the following equation –

where, supply voltage for the induction motor.

modulation index

supply D.C. voltage for inverter

V

But 270 V D.C. source is available in the laboratory, so the maximum voltage can be applied to the motor terminal is

V

11.2.2 Inverter Bridge Part :

By using power MOSFET IRF720 the inverter bridge circuit is developed, as we know inverter is used to invert DC voltage to AC voltage.

In Inverter Bridge four IRF720 MOSFETs are used. For single-phase A.C. we need two phases, one of which is earthed. Suppose we denote the MOSFETs by M1, M2, M3, and M4. Now we arrange the MOSFETs crosswise, M1 M3

M4 M2

In the bridge for the source pins of M1 and M3 are shorted and the drain pins of these two are connected to the sources of M4 and M2 respectively. Also drain pins of M4 and M2 are shorted.

Now source pins of M1 and M3 are connected with the positive side of 230V D.C. supply. The outputs of the controlling circuit are connected to the gate pins of all MOSFETs, as we know that, MOSFETs are automatic switches operated by gate pulse. By using same convention, we use control circuit pulses to ON or OFF the MOSFETs of the bridge to get sinusoidal A.C. supply. The drain pins of M4 and M2 are connected with the negative side of 230V D.C. supply. Now when M1 is ON due to gate pulse the D.C. current flows through it, then M2 is ON and make a closed loop through load attached in the middle of the bridge. So, the upper half of the sinusoidal pulse appears across the load. Next, M3 is ON and D.C. current flows through it. When M4 become ON, the current flows through the load and the

25lower part of the sinusoidal supply appears across the load. The Inverter circuit and its output is given in the following Figs. –

(a)

(b)

Fig. – 20 Circuitry of the total Power Part

(a) Inverter Bridge and (b) Output of the Inverter, fed to the motor

Now we get the desired A.C. supply for motor. Here every MOSFET is become ON when the amplitude of the gate pulse is 3.8V 4V.

11.3 Loading Part :

This part mainly consists of “SINGLE PHASE PERMANENT CAPACITOR INDUCTION MOTOR”. The load part motor is of rating,

26

Power = hp;

Current = 0.85 A;Voltage = 230 V;

Speed = 6500 r.p.m.;Power factor = 0.8

(a)(b)

Fig. – 21 Loading Part

(a) The Single Phase Induction Motor and (b) Rating of the Motor

As we know that in single phase the alternating phases are absent due to which the rotating flux is not generated; so rotation of the rotor is not possible.

For that reason permanent split capacitor is used to generate two balanced phases, due to which a rotating flux generated. There are several types of single-phase motors in market but permanent capacitor type motors are used because here two balanced phases generate rotating flux for which the backward rotating flux is absent.

Due to which motor become more efficient and operated in better power factor. This type of load is used in ceiling fans and table fans now a day.

In our project, the two phases coming from Inverter Bridge is fed to the load where any one phase is earthed; so that it acts as neutral in single-phase supply. By this supply starting torque is generated and the motor starts to rotate.

27

12. Test Tools :

Sl. No.

Description of Tools SpecificationName Use

1. Oscilloscope To get the response of the parts of the control circuit.

230 V, 20 MHz

2. Digital Multimeter

To measure the voltage, Resistances used, capacitor used, in the circuit. Also to verify whether parts of the circuit is active or not.

Resistance = upto 400 kVoltage = 0 to 1000 VCapacitor = 0 nF to 10 uF

13. Test Procedure :

For testing the circuitry we use oscilloscope to verify the response of the part of the circuit if the response is desirable then we proceed for the next portion of circuit. At the begging of the project we make the total possible circuit in MULTISIM simulation software and see the responses of every possible part of circuit. These responses are compared with the original circuit responses and if there is any wrong thing appear we clarify the original circuit for better response.

To understand the speed variation we use tachometer to measure the speed.

[Note: As we know that in PWM fed inverter the variation of should be constant

under base frequency. But here we can’t vary voltage and frequency simultaneously so we vary frequency only over base frequency to do the speed variation]

14. Test Results :

Type of wave Frequency Voltage (V)Square (above) 50 Hz 11 (p-p)Sine (above) 50 Hz 7 (p-p)

Square 5 kHz 11 (p-p)Triangular 5 kHz 10 (p-p)

Output Pulse - 4.5

28

15. Precautions :

To do this project various types of problems appear in front of us those are as follows with solve,

(i) First of all things, connection should be correct and perfect.(ii) During soldering careful about burning hazards.(iii) Use “chip base” to prevent the burning of chip due to direct

soldering.(iv) Soldering should be done in right process otherwise there may

appear short-circuit among pins and connecting wires.(v) Use Multi-Striped wire to prevent loose connection after soldering.(vi) All the open contacts should be closed to prevent shock hazards.(vii) Take measures to minimize the noise in the signal; like using

capacitor to block the noise.

16. Inference :

After finishing the “simulation of the circuit” by using Multisim software, we get the specific results and wave forms when we design the circuit part by part like “square wave generator, then second order filter, then we get sinusoidal pulse. Again square wave generator of high frequency pulse, then integrator and we get carrier signal triangular pulse”. But in the case of hardware design, many difficulties will occur such as frequency is not in the proper range, many noises in the required wave form etc. and so we use capacitors and resistors in much more quantity than that used in software.

From all the above analysis and waveforms, we conclude that if we vary the POT of Fig. 7(a), the frequency of the Square wave of Fig. 7(b) changed as the time constant RC will be changed. So the frequency of the sine wave will also vary and as well as comparison of Sine wave with the triangular wave will vary and the frequency of the pulses which trigger the MOSFETs will also vary and at last we will get the variable inverter output.

But, we know that, frequency control below base speed can carry out by

keeping ratio constant. Since there is no such option to vary the supply voltage

with its frequency, so the frequency as well as the speed of the motor is varied above the base speed.

DATASHEET OF OPERATIONAL AMPLIFIER (OP-AMP) LM741

August 2000

LM741Operational AmplifierGeneral DescriptionThe LM741 series are general purpose operational amplifi- ers which feature improved performance over industry stan- dards like the LM709. They are direct, plug-in replacements for the 709C, LM201, MC1439 and 748 in most applications.

The amplifiers offer many features which make their appli- cation nearly foolproof: overload protection on the

output, no latch-up when the common mode range is ex-ceeded, as well as freedom from oscillations.

The LM741C is identical to the LM741/LM741A except that the LM741C has their performance guaranteed over a 0˚C to+70˚C temperature range, instead of −55˚C to +125˚C.

Features

Connection Diagrams

Metal Can Package Dual-In-Line or S.O. Package

Note 1: LM741H is available per JM38510/1010100934102 00934103

Order Number LM741J, LM741J/883, LM741CN

Order Number LM741H, LM741H/883 (Note 1),LM741AH/883 or LM741CH

See NS Package Number H08C

Ceramic Flatpak

See NS Package Number J08A, M08A or N08E

Order Number LM741W/883See NS Package Number W10A

00934106

Typical Application

Offset Nulling Circuit

00934107

© 2004 National Semiconductor Corporation DS009341 www.national.com

Absolute Maximum Ratings (Note 2)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

LM741A LM741 LM741C

Supply Voltage ±22V ±22V ±18V

Power Dissipation (Note 3) 500 mW 500 mW 500 mW

Differential Input Voltage ±30V ±30V ±30V

Input Voltage (Note 4) ±15V ±15V ±15V

Output Short Circuit Duration Continuous Continuous Continuous

Operating Temperature Range −55˚C to +125˚C −55˚C to +125˚C 0˚C to +70˚C

Storage Temperature Range −65˚C to +150˚C −65˚C to +150˚C −65˚C to +150˚C

Junction Temperature 150˚C 150˚C 100˚C

Soldering Information

N-Package (10 seconds) 260˚C 260˚C 260˚C

J- or H-Package (10 seconds) 300˚C 300˚C 300˚C

M-Package

Vapor Phase (60 seconds) 215˚C 215˚C 215˚C

Infrared (15 seconds) 215˚C 215˚C 215˚C

See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of

soldering

surface mount devices.

ESD Tolerance (Note 8) 400V 400V 400V

Electrical Characteristics (Note 5)

Parameter Conditions LM741A LM741 LM741C Units

Min Typ Max Min Typ Max Min Typ Max

Input Offset Voltage TA = 25˚C

RS 10 k 1.0 5.0 2.0 6.0 mV

RS 50 0.8 3.0 mV

TAMIN TA TAMAX

RS 50 4.0 mV

RS 10 k 6.0 7.5 mV

Average Input Offset 15 µV/˚C

Voltage Drift

Input Offset Voltage TA = 25˚C, VS = ±20V ±10 ±15 ±15 mV

Adjustment Range

Input Offset Current TA = 25˚C 3.0 30 20 200 20 200 nA

TAMIN TA TAMAX 70 85 500 300 nA

Average Input Offset 0.5 nA/˚C

Current Drift

Input Bias Current TA = 25˚C 30 80 80 500 80 500 nA

TAMIN TA TAMAX 0.210 1.5 0.8 µA

Input Resistance TA = 25˚C, VS = ±20V 1.0 6.0 0.3 2.0 0.3 2.0 M

TAMIN TA TAMAX, 0.5 M

VS = ±20V

Input Voltage Range TA = 25˚C ±12 ±13 V

TAMIN TA TAMAX±12 ±13 V

www.national.com 2

Electrical Characteristics (Note 5) (Continued)

Parameter Conditions LM741A LM741 LM741C Units

Min Typ Max Min Typ Max Min Typ Max

Large Signal Voltage Gain TA = 25˚C, RL 2 k

VS = ±20V, VO = ±15V 50 V/mV

VS = ±15V, VO = ±10V 50 200 20 200 V/mV

TAMIN TA TAMAX,

RL 2 k,

VS = ±20V, VO = ±15V 32 V/mV

VS = ±15V, VO = ±10V 25 15 V/mV

VS = ±5V, VO = ±2V 10 V/mV

Output Voltage Swing VS = ±20V

RL 10 k ±16 V

RL 2 k ±15 V

VS = ±15V

RL 10 k ±12 ±14 ±12 ±14 V

RL 2 k ±10 ±13 ±10 ±13 V

Output Short Circuit TA = 25˚C 10 25 35 25 25 mA

Current TAMIN TA TAMAX 10 40 mA

Common-Mode TAMIN TA TAMAX

Rejection Ratio RS 10 k, VCM = ±12V 70 90 70 90 dB

RS 50, VCM = ±12V 80 95 dB

Supply Voltage Rejection TAMIN TA TAMAX,

Ratio VS = ±20V to VS = ±5V

RS 50 86 96 dB

RS 10 k 77 96 77 96 dB

Transient Response TA = 25˚C, Unity Gain

Rise Time 0.25 0.8 0.3 0.3 µs

Overshoot 6.0 20 5 5 %

Bandwidth (Note 6) TA = 25˚C 0.437 1.5 MHz

Slew Rate TA = 25˚C, Unity Gain 0.3 0.7 0.5 0.5 V/µs

Supply Current TA = 25˚C 1.7 2.8 1.7 2.8 mA

Power Consumption TA = 25˚C

VS = ±20V 80 150 mW

VS = ±15V 50 85 50 85 mW

LM741A VS = ±20V

TA = TAMIN 165 mW

TA = TAMAX 135 mW

LM741 VS = ±15V

TA = TAMIN 60 100 mW

TA = TAMAX 45 75 mW

Note 2: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device isfunctional, but do not guarantee specific performance limits.

3 www.national.com

Electrical Characteristics (Note 5) (Continued)Note 3: For operation at elevated temperatures, these devices must be derated based on thermal resistance, and Tj max. (listed under “Absolute MaximumRatings”). Tj = TA + (jA PD).

Thermal Resistance Cerdip (J) DIP (N) HO8 (H) SO-8 (M)

jA (Junction to Ambient) 100˚C/W 100˚C/W 170˚C/W 195˚C/W

jC (Junction to Case) N/A N/A 25˚C/W N/A

Note 4: For supply voltages less than ±15V, the absolute maximum input voltage is equal to the supply voltage.

Note 5: Unless otherwise specified, these specifications apply for VS = ±15V, −55˚C TA +125˚C (LM741/LM741A). For the LM741C/LM741E, these specifications are limited to 0˚C TA +70˚C.

Note 6: Calculated value from: BW (MHz) = 0.35/Rise Time(µs).

Note 7: For military specifications see RETS741X for LM741 and RETS741AX for LM741A.

Note 8: Human body model, 1.5 k in series with 100 pF.

Schematic Diagram

00934101

www.national.com 4

DATASHEET OF LOGIC INVERTERSN7405

DATASHEET OF LOGIC AND GATE74AC08

November 1988

Revised February 2005

74AC08 • 74ACT08Quad 2-Input AND Gate

General DescriptionThe AC/ACT08 contains four, 2-input AND

Features ICC reduced by 50% on 74AC only

Outputs source/sink 24 mA

Ordering Code:

Order NumberPackage

NumberPackage Description

74AC08SC M14A 14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow

74AC08SJ M14D Pb-Free 14-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide

74AC08MTC MTC14 14-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

74AC08MTCX_NL(Note 1)

MTC14 Pb-Free 14-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mmWide

74AC08PC N14A 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide

74AC08PC_NL(Note 1)

N14A Pb-Free 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide

74ACT08SC M14A 14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow

74ACT08SCX_NL(Note 1)

M14A Pb-Free 14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow

74ACT08MTC MTC14 14-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

74ACT08MTCX_NL(Note 1)

MTC14 Pb-Free 14-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mmWide

74ACT08PC N14A 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide

74ACT08PC_NL(Note 1)

N14A Pb-Free 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide

Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code. (PC not available in Tape and Reel.)

Pb-Free package per JEDEC J-STD-020B.

Note 1: “_NL” indicates Pb-Free package (per JEDEC J-STD-020B). Use this number to order device.

Logic Symbol Connection Diagram

IEEE/IEC

Pin Descriptions

Pin Names Description

An, Bn Inputs

On Outputs

FACT¥ is a trademark of Fairchild Semiconductor Corporation.

© 2005 Fairchild Semiconductor Corporation DS009914 www.fairchildsemi.com

Absolute Maximum Ratings(Note 2) Recommended Operating

Supply Voltage CC) 0.5V to 7.0V ConditionsDC Input Diode Current (IIK)

VI 0.5V 20 mA

VI VCC 0.5V 20 mA

DC Input Voltage (VI) 0.5V to VCC 0.5V

DC Output Diode Current (IOK)

VO 0.5V 20 mA

VO VCC 0.5V 20 mA

DC Output Voltage (VO) 0.5V to VCC 0.5V

DC Output Source

or Sink Current (IO) r50 mA

DC VCC or Ground Current

per Output Pin (ICC or IGND) r50 mA

Storage Temperature (TSTG) 65qC to 150qC

Junction Temperature (TJ)

PDIP 140qC

DC Electrical Characteristics for AC

Supply Voltage (VCC)

AC 2.0V to 6.0V

ACT 4.5V to 5.5V

Input Voltage (VI) 0V to VCC

Output Voltage (VO) 0V to VCC

Operating Temperature (TA) 40qC to 85qC

Minimum Input Edge Rate ('V/'t)

AC Devices

VIN from 30% to 70% of VCC

VCC @ 3.3V, 4.5V, 5.5V 125 mV/ns

Minimum Input Edge Rate ('V/'t)

ACT Devices

VIN from 0.8V to 2.0V

VCC @ 4.5V, 5.5V 125 mV/ns

Note 2: Absolute maximum ratings are those values beyond which damage

to the device may occur. The databook specifications should be met, with-

out exception, to ensure that the system design is reliable over its

power supply, temperature, and output/input loading variables. Fairchild

does not recommend operation of FACT¥ circuits outside databook

Symbol ParameterVCC TA 25qC TA 40qC to 85qC

(V) Typ Guaranteed LimitsUnits Conditions

VIH Minimum HIGH Level 3.0 1.5 2.1 2.1 VOUT 0.1V

Input Voltage 4.5 2.25 3.15 3.15 V or VCC 0.1V

5.5 2.75 3.85 3.85

VIL Maximum LOW Level 3.0 1.5 0.9 0.9 VOUT

0.1V Input Voltage 4.5 2.25 1.35 1.35 V or VCC 0.1V

5.5 2.75 1.65 1.65

VOH Minimum HIGH Level 3.0 2.99 2.9 2.9

Output Voltage 4.5 4.49 4.4 4.4 V IOUT 50 PA

VIN VIL or VIH

3.0 2.56 2.46 IOH 12 mA

4.5 3.86 3.76 V IOH 24 mA

5.5 4.86 4.76 IOH 24 mA (Note

3) VOL Maximum LOW Level 3.0 0.002 0.1 0.1

Output Voltage 4.5 0.001 0.1 0.1 V IOUT 50 PA

5.5 0.001 0.1 0.1

VIN VIL or VIH

3.0 0.36 0.44 IOL 12 mA

4.5 0.36 0.44 V IOL 24 mA

5.5 0.36 0.44 IOL 24 mA (Note 3)

IIN Maximum Input 5.5 r0.1 r1.0 PA VI VCC, GND

(Note 5) Leakage Current

IOLD Minimum Dynamic 5.5 75 mA VOLD 1.65V Max

IOHD Output Current (Note 4) 5.5 75 mA VOHD 3.85V Min

ICC Maximum Quiescent 5.5 2.0 20.0 PA VIN VCC

(Note 5) Supply Current or GND

Note 3: All outputs loaded; thresholds on input associated with output under test.

Note 4: Maximum test duration 2.0 ms, one output loaded at a time.

www.fairchildsemi.com 2

DC Electrical Characteristics for ACT

SymbolVCC TA 25qC TA 40qC to 85qC

(V) Typ Guaranteed LimitsUnits Conditions

VIH Minimum HIGH Level 4.5 1.5 2.0 2.0V

VOUT 0.1V

Input Voltage 5.5 1.5 2.0 2.0 or VCC 0.1VVIL Maximum LOW Level 4.5 1.5 0.8 0.8

VVOUT 0.1V

Input Voltage 5.5 1.5 0.8 0.8 or VCC 0.1V

VOH Minimum HIGH Level 4.5 4.49 4.4 4.4Output Voltage 5.5 5.49 5.4 5.4

4.5 3.86 3.76

V IOUT 50 PA

VIN VIL or

VIH

5.5 4.86 4.76

VOL Maximum LOW Level 4.5 0.001 0.1 0.1

V IOH 24 mA (Note 6)

Output Voltage 5.5 0.001 0.1 0.1

4.5 0.36 0.44

V IOUT 50 PA

VIN VIL or

VIH

5.5 0.36 0.44 V IOL 24 mA (Note 6)IIN Maximum Input Leakage Current 5.5 r0.1 r1.0 PA VI VCC, GND

ICCT Maximum ICC/Input 5.5 0.6 1.5 mA VI VCC 2.1V

IOLD Minimum Dynamic Output Current 5.5 75 mA VOLD 1.65V Max

IOHD (Note 7) 5.5 75 mA VOHD 3.85V MinICC Maximum Quiescent5.5 4.0 40.0 PA

VIN VCCSupply Current or GND

Note 6: All outputs loaded; thresholds on input associated with output under test.

Note 7: Maximum test duration 2.0 ms, one output loaded at a time.

AC Electrical Characteristics for ACVCC TA 25qC TA 40qC to 85qC

Symbol Parameter (V) CL 50 pF CL 50 pF

Units

(Note 8) Min Typ Max Min Max

5.0 1.5 5.5 7.5 1.0 8.5

tPHL Propagation Delay 3.3 1.5 7.0 8.5 1.0 9.0

5.0 1.5 5.5 7.0 1.0 7.5

Note 8: Voltage Range 3.3 is 3.3V r 0.3V

Voltage Range 5.0 is 5.0V r 0.5V

AC Electrical Characteristics for ACT

ns

n

VCC TA 25qC TA 40qC to 85qC

Symbol Parameter (V) CL 50 pF CL 50 pF

Units

(Note 9) Min Typ Max Min Max

tPLH Propagation Delay 5.0 1.0 6.5 9.0 1.0 10.0 ns

tPHL Propagation Delay 5.0 1.0 6.5 9.0 1.0 10.0 ns

Note 9: Voltage Range 5.0 is 5.0V r 0.5V

CapacitanceSymbol Parameter Typ Units Conditions

CIN Input Capacitance 4.5 pF VCC OPEN

CPD Power Dissipation Capacitance 20.0 pF VCC 5.0V

3 www.fairchildsemi.com

DATASHEET OF OPTOCOUPLERMCT2E

DATASHEET OF POWER MOSFETIRF720

BIBLIOGRAPHY

1. Alok Jain – “Power Electronics and Its Applications”, Second Edition, Penram International Publishing (India) Pvt. Ltd.

2. William H. Hayt, Jr., Jack E. Kemmerly, Steven M. Durbin – “Engineering Circuit Analysis”, Sixth Edition, Tata McGraw-Hill Publishing Company Limited, New Delhi.

3. A. Chakrabarti – “Circuit Theory (Analysis and Synthesis)”, Dhanpat Rai & Co. (Pvt.) Ltd.

4. Muhammad H. Rashid – “Power Electronics Circuits, Devices, and Applications”, Third Edition, Prentice-Hall of India Private Limited.

5. D. Roy Choudhury, Shalil B. Jain – “Linear Integrated Circuits”, Second Edition, New Age International (P) Limited, Publishers.

6. Nisit K. De, Prasanta K. Sen – “Electric Drives”, Prentice-Hall of India Private Limited.

7. M. Morris Mano – “Digital Logic and Computer Design”, Prentice-Hall of India Private Limited.

8. Dr. P. S. Bimbhra – “Generalized Theory of Electrical Machines”, Khanna Publishers.

9. Gopal K. Dubey – “Fundamentals of Electrical Drives”, Second Edition, Narosa Publishing House.

10. M. C. Sharma – “41 Projects Using 741 I.C.”, BPB Publications.