ELECTRICAL GROUP-1

ELECTRICAL ENGINEERING DEPARTMENT

SPEED CONTROL OF INDUCTION MOTOR USINGCYCLOCONVERTER :-

CONTENT IntroductionComponent DetailsSchematic DescriptionSoftware CodeCircuit Description/ConnectionCircuit OperationApplicationFuture EnhancementConclusionReference

INTRODUCTION:-Speed control of induction motor is necessary in industrial applications. There are several methods for the speed control of induction motor . Cyclo-converters are used in very large variable frequency drives with ratings from few megawatts up to ten times of megawatts. A cyclo-converter is controlled through the timing of its firing pulses, so that it produces an alternating output voltage. It can also be considered as a static frequency changer and typically contains silicon controlled rectifiers. The development of the semiconductor devices has made it possible to control the frequency of the cyclo-converter according to the requirement and deliver a large amount of controlled power with the help of semiconductor switching devices like Thyristors, MOSFET’s in order to get alternating output of variable frequency.

Here a microcontroller is used to give commands to the cyclo-converter hence it controls the AC motor accordingly. We are controlling the AC motor by means of a TRIAC.

COMPONENT DETAILS :-

TRIAC (BT136)

CONT…….

BT136 is a triac device which have three terminal i.e. main terminal 1,mainterminal 2 and Gate terminal. This device is connect to a optocoupler i.e. MOC135 to control the motor terminal and speed of the motor. when the optocoupler is activated than two terminal of triac will shorted. So the motor will rotate.

A triac is basically a bidirectional electronic switch, which can conduct current in either direction when it is triggered. The triggering can be either a positive or negative voltage applied to its gate electrode. By applying a steady state gate signal, the triac may be triggered into a low impedance state where conduction across the main terminals will occur. The gate signal polarity need not follow the main terminal polarity. Gate requirement vary depending on the direction of the main terminal current and the gate current.

COMPONENT DETAILS 1:

RESISTOR CAPACITOR

Cont…RESISTOR :A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current through it in accordance with Ohm's law:V = IR . Calculation of resistance is as follow….

Colour 1st band 2nd band 3rd band (multiplier)

4th band (tolerance)

Temp. Coefficient

Black 0 0 ×100

Brown 11 1 ×101 ±1% (F) 100 ppm

Red 2 2 ×102 ±2% (G) 50 ppm

Orange 3 3 ×103 15 ppm

Yellow 4 4 ×104 25 ppm

White 9 9 ×109

Gold ×10−1 ±5% (J)

Silver ×10−2 ±10% (K)

None ±20% (M)

Cont….CAPACITOR:A capacitor or condenser is a passive electronic component consisting of a pair of conductors separated by a dielectric. When a potential difference exists across the conductors, an electric field is present in the dielectric. This field stores energy and produces a mechanical force between the conductors. The effect is greatest when there is a narrow separation between large areas of conductor, hence capacitor conductors are often called plates. Capacitors are widely used in electronic circuits to block the flow of direct current while allowing alternating current to pass, to filter out interference, to smooth the output of power supplies, and for many other purposes. They are used in resonant circuits in radio frequency equipment to select particular frequencies from a signal with many frequencies.

COMPONENT DETAILS 2:

DIODE(1N4002)

REGULATOR( LM78XX/LM78XXA )

DIODE:

DIODE IS A SEMICONDUCTOR DEVICE..THE VARIOUS DIODE IS AS FOLLOW….

Diode Zener diode Schottky diode Tunnel diode

Light-emitting diode Photodiode Varicap Silicon controlled rectifier

VOLTAGE REGULATOR 7805 :

The LM78XX/LM78XXA series of three-terminal positive regulators are available in the TO-220/D-PAK package and with several fixed output voltages, making them useful in a Wide range of applications. Each type employs internal current limiting, thermal shutdown and safe operating area protection, making it essentially indestructible. If adequate heat sinking is provided, they can deliver over 1A output Current. Although designed primarily as fixed voltage regulators, these devices can be used with external components to obtain adjustable voltages and currents.

Features:• Output Current up to 1A. • Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V. • Thermal Overload Protection. • Short Circuit Protection.• Output Transistor Safe Operating Area Protection.

COMPONENT DETAILS 3:

OPTOCOUPLER

TRANSFORMER

Optocoupler is a Triac Driver MOC 135 which have 6 terminal and voltage range give up to 115 volt AC . In other word it is a device which is generally used for control the Triac and it isolate/divide the DC to AC.

When an electrical signal is applied to the input of the optocoupler, its LED lights, its light sensor then activates, and a corresponding electrical signal is generated at the output. Unlike a transformer, the optocoupler allows for DC coupling and generally provides significant protection from serious overvoltage conditions in one circuit affecting the other. With a photodiode as the detector, the output current is proportional to the amount of incident light supplied by the emitter.

Transformer is a static device. Here 230/9 volt transformer generally used. where the red color wire is known as primary winding and Yellow color wire is known as secondary winding.

(VS) =voltage in the secondary winding , (VP)= the primary voltag, and is given by the ratio of the number of turns in the secondary (NS) to the number of turns in the primary (NP)

MOC-135 : TRANSFORMER:

COMPONENT DETAILS 4 :

16*2 LCDATMEGA16 Microcontroller

MICROCONTROLLER:A Micro controller consists of a powerful CPU tightly coupled with memory RAM, ROM or EPROM), various I/O features such as Serial ports, Parallel Ports, Timer/Counters, Interrupt ,Controller, Data Acquisition interfaces-Analog to Digital Converter (ADC), Digital to Analog Converter (DAC), everything integrated onto a single Silicon Chip.We use AVR microcontroller here due to better control.We use ATMEGA16 here..Features :• High-performance, Low-power AVR® 8-bit Microcontroller• Advanced RISC Architecture– 131 Powerful Instructions – Most Single-clock Cycle Execution– 32 x 8 General Purpose Working Registers– Fully Static Operation– Up to 16 MIPS Throughput at 16 MHz– On-chip 2-cycle Multiplier• Nonvolatile Program and Data Memories– 16K Bytes of In-System Self-Programmable FlashEndurance: 10,000 Write/Erase Cycles– Optional Boot Code Section with Independent Lock Bits In-System Programming by On-chip Boot Program True Read-While-Write Operation– 512 Bytes EPROMEndurance: 100,000 Write/Erase Cycles– 1K Byte Internal SRAM– Programming Lock for Software Security

• JTAG (IEEE std. 1149.1 Compliant) Interface– Boundary-scan Capabilities According to the JTAG Standard– Extensive On-chip Debug Support– Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface  • Peripheral Features– Two 8-bit Timer/Counters with Separate Prescalers and Compare Modes– One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and CaptureMode– Real Time Counter with Separate Oscillator– Four PWM Channels– 8-channel, 10-bit ADC8 Single-ended Channels7 Differential Channels in TQFP Package Only2 Differential Channels with Programmable Gain at 1x, 10x, or 200x– Byte-oriented Two-wire Serial Interface– Programmable Serial USART– Master/Slave SPI Serial Interface– Programmable Watchdog Timer with Separate On-chip Oscillator– On-chip Analog Comparator

Special Microcontroller Features– Power-on Reset and Programmable Brown-out Detection– Internal Calibrated RC Oscillator– External and Internal Interrupt Sources– Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby and Extended Standby

SPECIAL FEATURES:-• I/O and Packages– 32 Programmable I/O Lines– 40-pin PDIP, 44-lead TQFP, and 44-pad QFN/MLF• Operating Voltages– 2.7 - 5.5V for ATmega16L– 4.5 - 5.5V for ATmega16• Speed Grades– 0 - 8 MHz for ATmega16L– 0 - 16 MHz for ATmega16• Power Consumption @ 1 MHz, 3V, and 25C for ATmega16L– Active: 1.1 mA– Idle Mode: 0.35 mA– Power-down Mode: < 1 µA

LCD(Liquid Crystal Display):A liquid crystal display (LCD) is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals. Liquid crystals do not emit light directly.

LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images which can be displayed or hidden, such as preset words, digits, and 7-segment displays as in a digital clock. They use the same basic technology, except that arbitrary images are made up of a large number of small pixels, while other displays have larger elements.we use 16*2 lcd in our project.

SCHEMATIC DIAGRAM:

Cont…When 230 volt,50Hz power supply is given to the transformer of primary side than by the help of flux linkage mechanism the 9 volt,50Hz output voltage is developed at the output side.

As the output voltage is pulsating AC , so we convert it to pulsating DC by help of Bridge rectifier circuit. so we get pulsating 12 volt AC voltage at the end as shown in figure.

Now connect a 1000µf,30 volt capacitor for smoothing circuit operation(If output is 12volt,50Hz) or we can connect two capacitor i.e. one is electrolyte capacitor rating 470µf,50volt and another is ceramic capacitor i.e. 0.01µf (if we have 9 volt,50Hz output).

Now connect a 7085 voltage regulator to the circuit for getting the constant 5 volt to give the microcontroller .

For LED use we have to connect a 390 resistor and a 10µf,25volt capacitor and a LED .

This is all about the regulated power system circuit.

WAVEFORM :-

CYCLO_CONVERTER DIAGRAM :-

A cyclo-converter is a power electronic device used to convert constant voltage constant Frequency AC power to adjustable voltage adjustable frequency AC power without a DC link. In among all the methods this method is simple, reliable and economical. The various speed of induction motor is obtained by varying the supply frequency by using cyclo-converter.

The cycloconverter has four thyristors divided into a positive and negative bank oftwo thyristors each. When positive current flows in the load, the output voltage is controlled by phase control of the two positive bank thyristors whilst the negative bank thyristors are kept off and vice versa when negative current flows in the load. An idealised output waveform for a sinusoidal load current and a 45 degrees load phase angle.It is important to keep the non conducting thyristor bank off at all times, otherwise the mains could be shorted via the two thyristor banks, resulting in waveform distortion and possible device failure from the shorting current. A major control problem of the cycloconverter is how to swap between banks in the shortest possible time to avoid distortion whilst ensuring the two banks do not conduct at the same time.

DESCRIPTION:-

SOFTWARE CODE:-

Basic C program structure: //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -//Basic blank C program that does nothing// Includes//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -#include <avr/io.h> // SFR declarationsVoid main (void){While (1);{Body of the loop // Infinite loop}} // match the braces

Cont…#include<avr/io.h>#define F_CPU 1000000#include<util/delay.h>#define KEYPAD_PORT PORTA#define KEYPAD_PIN PINA#include<avr/keypad.h>

void main(void){

DDRA=0x0f;

DDRD=0x0f;unsigned char keypad_value;

while(1){

keypad_value = read_keypad();if(keypad_value != 0xff){

if(keypad_value == 0x02)PORTD=0x0A;

else if(keypad_value == 0x08)PORTD=0x05;

else if(keypad_value == 0x04)PORTD=0x02;

else if(keypad_value == 0x06)PORTD=0x08;

else if(keypad_value == 0x05)PORTD=0x0F;

else;}else;

}} /*End of Program*/

CIRCUIT DESCRIPTION:

CIRCUIT CONNECTION :-

From the Output of the regulated power circuit, connect the output(5VOlt) to the vcc pin of the microcontroller through a 10k resistor.another supply is to be connected to the optocoupler(moc135) pin no-1.

The terminal of lcd (d0 – d7 ) should be connected to the port-C of microcontroller.

Cont….

Port-a connect to the keypad and port-d will be the output of the microcontroller.

Moc-135 pin no 4&5 should connect to the pin of triac(bt-136).1k resistor should connect to the collector terminal point of the moc-135.

The two terminal of bt-136 connect to the motor’s two terminal.

When the motor is connect to the BT-136 then motor will not rotate if the microcontroller is not active.

When microcontroller is turn on by external power supply then if keypad 1 is push then input is high (i.e 4.5 to 4.8volt).

So it will turn on the internal part of LED of MOC-135.Due to the high intensity of light it will turn on the photo-transistor of the MOC-135.So photo-transistor give high output current to the BT-136,Which will rotate the motor at high speed.

CIRCUIT OPERATION:-

Cont….

Again when keypad-2 is pushed then it will provide high input(i.e approx. 2.5-2.7volt) due to the presence of resistance.so light intensity will low as compared to 1st ,which will activate the photo-transistor and low current output will produce due to low light intensity.

That’s why the motor will rotated slowly as comapred to 1st.and so on...By this way we can control the speed of the motor using microcontroller.

APPLICATION:-

INDUSTRIAL APPLICATIONCELLING FAN SPEED CONTROLADVANCE ROBOTICS SYSTEMCOMMERCIAL USED

FUTURE ENHANCEMENT :

This project can be used to control AC motor by means of cyclo-converter which will be very helpful to us in the industrial applications. In industrial areas we can implement this project to control the rotating ac machines effectively.

From this work and result analysis, it is observed that speed of an induction motor can be efficiently controlled by using Cyclo-converter. The role of Cyclo-converter in speed control of induction motor is to vary the supply frequency which in turn , changes the speed of motor.

CONCLUSION:-

REFERENCE :-Fundamentals Of Micro processors and Micro computers -B.Ram Micro processor Architecture, Programming & Applications -Ramesh S. Gaonkar Electronic Components -D.V. Prasad WEB Resources:Elements of electronic engineering by N N Rao.www.wikipedia.comhttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Bipolar_junction_transistorhttp://en.wikipedia.org/wiki/zener_diodehttp://en.wikipedia.org/wiki/resistorhttp://en.wikipedia.org/wiki/diodehttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/potentiometerhttp://en.wikipedia.org/wiki/capacitorhttp://en.wikipedia.org/wiki/LEDhttp://en.wikipedia.org/wiki/relay

THANK YOU…

PRESENTED BY :GROUP EE-01