Wireless Speed Control of an Induction Motor Using PWM Technique with ZIGBEE

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International Journal of Research in Information Technology (IJRIT)

www.ijrit.com ISSN 2001-5569

Wireless Speed Control of an Induction Motor Using PWM Technique with ZIGBEE

Sweety Jadhav¹, Sfurti chinchavade², Professor Deepika Srivastava³

1(Electrical Engineering Department, Pune, JSPM’s BSIOTR Pune, Maharastra, India

E-mail- [email protected])

2(Electrical Engineering Department, Pune, JSPM’s BSIOTR Pune, Maharastra, India

E-mail- [email protected])

3( Electrical Engineering Department, Pune, JSPM’s BSIOTR Pune, Maharastra, India

E-mail- [email protected])

Abstract

Induction motors are the most extensively used motors in most power-driven home appliances, agricultural and industrial applications. Simple and rugged design, low cost, low maintenance and direct connection to an AC power source are the chief advantages of an AC induction motor. Many applications need variable speed operation and one of them is a simple fan load. The DTMF generator which generates the analogue output signal for the corresponding button pressed using key pad. This analogue output is fed to the zigbee transmitter and, transmitted signal receives at Zigbee receive there the decoding takes place and this decoding data is given to the AVR Micro controller. The software in the AVR receives the signal and accordingly drives the TRIAC Circuit, which in turn is connected to load serially. The experimental work a prototype model is built through the AVR microcontroller (ATMEL AVR) which is used to generate the PWM pulses for speed control of the motor. The main aim of the this project is to design an real time electronic control system that can be used to control the speed of motors kept at remote locations using an embedded technology.

Keywords: Induction motor, Speed control, Pulse Width Modulation (PWM), Zigbee, AVR

1. Introduction

Many industrial applications require adjustable speed and constant speed for improvement of quality product. The rapid advances in automation and power electronics due to their several advantages such as relatively small size, low losses, market availability and low cost, the field of adjustable speed drives continuously growing. There are various alternate techniques in the selection of speed of the drive system.

Induction motors are used in many applications such as HVAC, Industrial drives control, automotive

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pump, Compressors, domestic applications and paper machines etc.

The microcontroller provides the pulse width variation signal which is given to the TRIAC. Pulse Width Modulation (PWM) is a common technique for speed control which can overcome the problem of the poor starting performance of a motor. It combines the technique of PWM generation and the control of speed of motor by variable frequency method using microcontroller. The basic principle involved in this project is variable frequency where, the speed can be controlled by using PWM waves generated by AVR Microcontroller. This has lot of domestic and industrial applications in our daily life. The wireless technology also helps the disables; handicapped, paralyzed people and also the elder people used these technology further betterments. The main objective of this project is to control the speed of the single phase induction motor by variable frequency method using wireless technology using AVR microcontroller

2. OVERALL DESIGN

In this project, wireless speed control of single phase induction motor, this system uses the digital controller AVR for controlling the system operation. AVR is a flash type in which we have already programmed.

Microcontroller has an inbuilt PWM generator which generates PWM wave by using software instructions.

The implementation of the project is shown in the block diagram .When the user presses a specific key the DTMF Generator generates the Corresponding DTMF analogue output. This analogue output is fed to the Zigbee Transmitter. The DTMF provides an output that is combination of two different Frequencies of the specific key pressed. So the output from the Zigbee Transmitter will be the Combination of the carrier frequency and analogue frequency generated by the DTMF IC. At the other end the Zigbee Receiver picks up the signals by tuning in to the carrier frequency of the zigbee Transmitter. The output of the zigbee receiver accordingly generates the BCD (Binary coded Decimal) output from this IC. The Output that is digital is fed to the AVR Micro Controller. The AVR is initially programmed with the help of the AVR programmer. This AVR Programmer is connected to the PC through the parallel port. The software is developed using the assembly language of the AVR. This programming is done using the software Called AVR STUDIO.

The software in the AVR will decode the digital data obtained from the Zigbee Receiver. After decoding the data it takes the command from the user and depending on the command received by the user the AVR will accordingly generate a Pulse Width Modulation output at a fixed known frequency. As the user presses different buttons the AVR decodes the same and generates the frequencies as required by the user. This PWM Output is connected to the signal conditioning circuit and to the load.

3. HARDWARE DESIGN

The wireless speed control of AC drive system consists of a AVR controller, display unit, power supply unit, Optocoupler and ZigBee transceiver. The corresponding button pressed using keypad analogue output is fed to Zigbee transmitter. Zigbee receiver picks up the signal and given to the AVR microcontroller it generates PWM pulse and accordingly drives the triac circuit

, IJRIT-290 4. DESCRIPTION OF FUNCTIONAL BLOCK DIAGRAM

When the user presses a specific key the DTMF Generator generates the Corresponding DTMF analogue output. This analogue output is fed to the Zigbee Transmitter.Zigbee can be used to transmit and receive data at 9600 baud rates from any standard CMOS/TTL source. The options are provided to vary the frequency depending on the Zigbee Receiver. Parameter such has amplitude and frequency can be varied by varying the corresponding potential meters. The DTMF provides an output that is combination of two different Frequencies of the specific key pressed. So the output from the Zigbee Transmitter will be the Combination of the carrier frequency and analogue frequency generated by the DTMF IC. At the other end the Zigbee Receiver picks up the signals by tuning in to the carrier frequency Of the Zigbee Ttransmitter.

The output of the Zigbee Receiver accordingly generates the BCD (Binary coded Decimal) output from this IC. The Output that is digital is fed to the AV R Micro Controller. The AVR is initially programmed with the help of the AVR programmer. This AVR Programmer is connected to the PC through the parallel port.

The software is developed using the assembly language of the AVR. This programming is done in the software AVR Studio.

(a) Transmitter section for speed control of Induction motor using wireless technology

(b) Receiver section and Drive circuit for speed control of Induction motor using wireless technology

Fig 3.1: Block diagram of the proposed system ZIGBEE TRANSMITTER DTMF

ENCODER KEYPAD

AVR MICRO COTROLL

ER

L

Zigbee

Receiver ^OPTO- TRIAC

ISOLATOR

POWER SUPPLY UNIT

INDUCTION MOTOR

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3.1Microcontroller

The digital controller ATMEGA16A (AVR) is a general purpose 16 bit digital controller which is used to combine the calculation capability of digital signal processor and controlling capability of AVR microcontroller, to achieve precise control. ATMEGA16A (AVR) has high performance modified RISC CPU. This controller is used to generate PWM pulse to control the speed of the motor by collecting speed values from sensor.

3.2 Display unit

LCD display unit is used to display the data sent to microcontroller by the sensor. LCD displays 8 lines with 21 characters in each line.

3.3 Driver unit

The triggering circuit is nothing but a switch which alerts the supply to the induction motor by turning on/off, on application of the gate pulse coming from the ccpl pin of the controller.

3.4 ZigBee module

ZigBee transceiver module contains ZigBee transmitter and ZigBee receiver. The Xbee RF Modules are designed to operate within the ZigBee protocol and support the unique needs of low-cost, low-power wireless sensor networks. The modules require minimal power and provide reliable delivery of data between remote devices. The modules operate within the ISM 2.4 GHz frequency band. It operates over a range of 100-200 meters. The receiver module consists of a Zigbee RF module which is connected to computer system. Thus the monitoring data received by ZigBee module is directly transferred to computer system

.

5. DTMF GENERATOR

The DTMF system uses eight different frequency signals transmitted in pairs to represent sixteen different numbers, symbols or letters. These tones lie within the speech band of 300 to 3400Hz, and are chosen one tone from the higher group and the other from the lower group of frequencies. Each dialed digit is represented by a pair of sine wave tones. A valid DTMF signal is the sum of two tones, one from a lower group (697 to 941Hz) and the other from a higher group (1209 to 1633Hz). Each group contains four individual tones. The DTMF dialing scheme is as shown in Fig.2. The DTMF encoder (UM 91215B) is most widely used to transfer information between radio transceivers and remote control applications in industries. Approximate low and high frequencies tone signals are selected by pressing suitable keys in the key pad. The output of the DTMF encoder is taken out from the tone out pin and this signal is applied to the zigbee transmitter to transmit the signal in to the medium.

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Fig.2. DTMF dialing key pad for generation of tones

6. PULSE WIDTH MODULATION (PWM):

PWM is a powerful technique for controlling analog circuits with a processor's digital outputs. PWM is employed in a wide variety of applications, ranging from measurement and communications to power control and conversion.

Fig 3 Typical waveform of PWM

The voltage or current source is supplied to the analog load by means of a repeating series of on and off pulses. The on-time is the time during which the DC supply is applied to the load, and the off-time is the periods during which that supply is switched off.

Given a sufficient bandwidth, any analog value can be encoded with PWM loads, inductive and capacitive alike, require a much higher modulating frequency than 10 Hz.

The duty cycle would still be 50%, but the bulb would appear brightly lit for the first five seconds and off for the next. In order to see a voltage of 4.5 volts in the bulb, the cycle period must be short relative to the load's response time to a change in the switch state.

ALGORITHM

Step1: Start

Step2: Initialise all ports

Step3: By using Keypad function, set the value of speed Step4: Send character as compare to the number

Step5: Generate PWM as per the receiving character Step6: PWM given to the BT136

Step7: Rotate motor at desired speed

, IJRIT-293 OVERALL HARDWARE KIT OF PROJECT

Fig: 4. Transmission section for speed control of Induction motor

Fig5: Receiving section for speed control of induction motor

7. RESULT

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THIS PAPER CONCERNED ON THE EXPERIMENTAL STUDIES ON SIMPLE MOTOR LOAD FOR SPEED CONTROL USING WIRELESS TECHNOLOGY THROUGH THE MICROCONTROLLER.THE EXPERIMENT IS CONDUCTED BY PLACING MOTOR AT A DISTANCE OF ABOUT 20-25 METERS AND TESTED THE MOTOR TO OBTAIN VARIOUS SPEEDS BY PRESSING THE DIFFERENT KEYS IN THE KEYPAD.HERE T ON IS MAINTAINED CONSTANT AND T OFF IS VARIED ACCORDINGLY

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Table 1

Serial no Frequency Speed of the

motor (rpm)

1 20 325

2 60 714

3 80 1020

4 99 1103

Table 1 Shows the frequency and speed of motor

Figure shown the results of single phase induction motor when it was running at different frequency. In the test, the lowest frequency is 20 Hz at 325 rpm while the highest frequency is 99 Hz at 1103 rpm

.

Fig 6: shows the Speed of the motor at different frequency

8. CONCLUSION

0 200 400 600 800 1000 1200

20 40 60 80 99

Speed of motor in rpm

Frequency in Hz

Speed vs frequency

Speed of motor (rpm)

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MOTOR IS PERFORMED USING WIRELESS TECHNOLOGY BY THE AVR(ATMEGA16) MICROCONTROLLER.THE EXPERIMENTAL RESULTS ARE ANALYZED AND, IT’S FOUND THAT THE SPEED OF THE INDUCTION MOTOR IS CONTROLLED EFFECTIVELY USING WIRELESS TECHNOLOGY KEEPING 22 METERS AS THE DISTANCE BETWEEN TRANSMITTER AND RECEIVER SECTION. THE HARDWARE MAKES USE OF ZIGBEE PROTOCOL FOR COMMUNICATING THE PWM CONTROL SIGNALS FROM THE MICROCONTROLLER.THUS, SPEED OF MOTOR CAN BE EFFECTIVELY CONTROLLED BY USING THE DESIGNED HARDWARE SETUP.

REFERENCES

[1] “Microcontroller Based Speed Control of Induction Motor using wireless technology” by Nagshekhar Reddy,IJESE ISSN: 2319-6378, issue 9 July 2013.

[2] “High performance speed sensor less control of induction motor drive using a minimalist single phase PWM converter” by Olorunfemi Ojo,IEEE vol41, no 4 July/August 2005.

[3] “Sensor less indirect stator field orientation speed control for single phase induction motor” by Mohamed Jemli IEEE TRANSACTIONS on power electronics, vol.24, no.6, June2009.

[4] “Accurate low speed and torque control for induction motor with secondary current feedback using MI sensor installed in shaft hole” by T. Ito, Y. Nakamura IEEE TRANSACTIONS on magnetics, vol.42,no.10 October2006.

[5] “Wireless speed control of Ac drive system” by Prof. Sethu priyan, IJAREEIE vol 3, special issue 2, April 2014.

[6] “Speed is monitoring and protection of motor using zigbee communication” Prof P.E. Elavenil, IJSRET vol 2, issue 11 February 2014.

[7] “Microcontroller based speed control of three phase induction motor using V/F method” by Prof Deepali S.Shirake IJSRP, volume 3, issue 2 February 2013.

[8] “A comparative study of control techniques for PWM rectifiers in AC adjustable speed drive” by Mariusz Malinowski IEEE TRANSACTIONS on power electronics, vol.18, no. 6 November 2003.

[9] B.K. bose, “Adjustable speed AC drives – A technology status review”, IEEE transaction, Vol.70, No.2, PP-116-33, Feb-1982.

[10] “R.Khan and M.M.S. Riyadh, “PWM Speed Control of AC Single Phase Induction Motor Using MCU Series Combined With TRIAC Technology”, International Journal of Computer and Electrical Engineering, Vol. 3, No. 6, December 2011.

[11] S.M.Wankhede, R.M.Holmukhe, Miss.A.M.Kadam, Miss.P.R shinde, P.S.Chaudhari, “Micro controller Based Control of Three Phase Induction Motor Using PWM Technique”,ICEEN, 2011.

[12] A.M.Jain, P.S.Joshi “Wireless speed control of an induction motor using PWM technique with GSM”, IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE) e-ISSN: 2278- 1676,p-ISSN: 2320-3331, Volume 6, Issue 2 (May. - June. 2013).