Post on 10-Mar-2018
transcript
SPEED CONTROL OF SINGLE PHASE INDUCTION MOTOR BY
PWM TECHNIQUE USING LABVIEW
A.Manikandan1, M.Naveen
2, P.Prakash
3
U.G. Students, Department of EEE, Mahendra Engineering College, Namakkal.
Dr.S.Umamaheshwari4, Prof/Dept of EEE, Mahendra Engineering College, Namakkal
B.S.Rajan5, Assistant Professor, Department of EEE, Mahendra Engineering College,
Namakkal
ABSTRACT:
This proposed system is to control the
speed of single phase induction motor by
PWM technique. This technique has high
efficiency to drive an induction motor
using pulse width modulation technique
(PWM) and is designed for minimal cost.
The circuit is controlled by using
LabVIEW Software with Arduino (Atmel
328) controller. The reason of using
LabVIEW domain is of its strong
interface, simplicity of its Graphical
Programming Code combined with built in
tools designed especially for testing,
measuring and controlling. With PWM
technique it is competent of supplying
high frequency to run the induction motor
at accurate speed. Through DAQ the signal
is acquired and the system is controlled.
KEYWORD: Atmel328 controller,
Optocoupler, Induction motor, LabVIEW,
DAQ.
I. INTRODUCTION
Induction motors are widely used in
industrial and commercial utility
applications. It gained momentum because
of its high efficiency and various speed
ranges. Compare to DC machines, AC
machines are mostly used in variety of
applications due to their simplicity and
low cost. Motor control applications span
everything from residential washing
machine, fans, traction control system and
various industrial drives. LabVIEW is a
graphical programming code for data
acquisition, analysis, and presentation. The
components of LabVIEW are front panel
and block diagram. Front panel is used to
build controls and indicators and block
diagram contains pictorial representation
of code. In this work LabVIEW based
control is designed to control the speed of
induction motor using PWM technique.
Dynamic characteristics of electrical
machines are learnt using simulation tools
available in LabVIEW. Usage of virtual
instrumentation software to analyze and
control is not only subjected to cost
reduction but also gives enhanced
performance.
II.BLOCK DIAGRAM
Fig.1 Block diagram of Proposed System
The system existing is similar as that of
speed control using voltage control method
in which voltage is varying from zero to
maximum value. Here Pulse width
modulation technique to control the speed
of induction motor is proposed which
produces the lower order harmonics. In the
Figure 1, the PWM controlled MOSFET is
connected in series with bridge rectifier
and the input of bridge rectifier is
connected in series with load and the
output terminal is connected across power
transistors. Initially its known fact that
current cannot flow through the open
circuit therefore power transistor is in OFF
state. If the bridge rectifier circuit is short
circuited, the power transistor gets
switched ON and current flows through the
rectifier to load. The power to the load is
controlled by changing the duty cycles of
PWM pulses. The pulses are synchronized
with supply phase by zero sensing point.
III.HARDWARE SYSTEM
a) LABVIEW
LabVIEW programs are called virtual
instrumentation (VI) because their
appearance and operation imitate physical
instruments, such as oscilloscopes and
Multi Meters. LabVIEW is a graphical
programming code used to acquire, control
and store data. It is possible to
communicate with hardware by using
DAQ, RS232 interface. Whenever the
serial port is ready to transmit data, it
fetches data to hardware buffer. The
controller receives data through the
interfacing devices and the motor is
controlled by changing the pulse width
modulation.
b) ATMEL 328
The high-performance, low-power Atmel
8-bit AVR RISC-based microcontroller
combines 16KB ISP flash memory, 1KB
SRAM, 512B EEPROM, an 8-channel/10-
bit A/D converter (TQFP and QFN/MLF),
and debug WIRE for on-chip debugging.
The device supports a throughput of 20
ATMEL
328
Controller
MIPS at 20 MHz and operates between
2.7-5.5 volts. By executing powerful
instructions in a single clock cycle, the
device achieves throughputs approaching 1
MIPS per MHz, balancing power
consumption and processing speed.
c) OPTO-COUPLERS
Opto-couplers are made up of a light
emitting device, and a light sensitive
device, all wrapped up in one package, but
with no electrical connection between the
two, just a beam of light. The light emitter
is nearly always an LED. The light
sensitive device may be a photodiode,
phototransistor, or more esoteric devices
such as Thyristors, TRIACs etc.
A lot of electronic equipment nowadays is
using opto coupler in the circuit. An opt
coupler or sometimes refer to as opt
isolator allows two circuits to exchange
signals yet remain electrically isolated.
This is usually accomplished by using
light to relay the signal. The standard opt
coupler circuits design uses a LED shining
on a phototransistor-usually it is an NPN
transistor and not PnP. The signal is
applied to the LED, which then shines on
the transistor in the IC.
Most commonly used is an opto-coupler
MOC3021 an LED Diac type combination.
This IC is interfaced with a
microcontroller and an LED is connected
in series to the IC, which glows to indicate
a logic High pulse from the
microcontroller so that we can know that
current is flowing in internal LED of the
opto-IC. When logic high is given current
flows through LED from pin1 to 2. So in
this process LED light falls on DIAC
causing 6 & 4 to close. During each half
cycle current flows through gate, series
resistor and through opto-diac for the main
Thyristors / triac to trigger for the load to
operate.
d) SOLID STATE RELAY (SSR)
Fig.2 Circuit diagram for SSR
SSR stands for Solid State Relay. SSRs
have no movable contacts. SSRs are not
very different in operation from
mechanical relays that have movable
contacts. SSRs, however, employ
semiconductor switching elements, such as
thyristors, triacs, diodes, and transistors.
Furthermore, SSRs employ optical
semiconductors called photo-couplers to
isolate input and output signals.
Photocouplers change electric signals into
optical signals and relay the signals
through space, thus fully isolating the
input and output sections while relaying
the signals at high speed. SSRs consist of
electronic parts with no mechanical
contacts.
IV. SIMULATION RESULT
Figure 4 indicates the front panel of
LabVIEW in running condition of the
induction motor. Variation of speed with
respect to time controlled by PWM
techniques is shown in Figure 5. It clearly
shows that the speed of the motor attains
the rated speed within the short duration
and it tabulated in the Table 1.
Fig.4 Front panel at running condition
Table1. Speed Vs Time
V. GRAPHICAL RESULTS
A) PROPOSED SYSTEM
Fig.5 Graphical representation of user
speed control with respect to time
Fig.6 Graphical representation of PWM
wave
Speed
(rpm)
Time
(ms)
Frequency
(UHZ)
1000 10 36
2000 20 73
3000 30 108
4000 40 145
5000 50 185
CONCLUSION
LabVIEW based speed control of single
phase induction motor using pulse width
modulation technique is seems to be more
31% more efficient when compare with
existing system. The accurate speed can be
achieved by using this technique. By using
this technique user can control the speed of
induction motor according to the
requirements.
REFERENCES
[1]. Shilpa V. Kailaswar Prof.
R.A.Keswani/International journal of
Engineering Research and application
(IJERA),PP, 1732-1736. Speed control of
three induction motor by V/F method for
batching motion system.
[2]. S .M. Wankhede, R.M. Holmukhe,
miss A.M. Kadam. Miss P.R. Shinde, P.S.
Chaudhari. Microcontroller Based Control
of three phase induction motor using
PWM technique.
[3]. Application Note-017, PWM Motor
Drives-Theory and Measurements
Considerations.
[4]. The 8052 Microcontroller and
Embedded system Pearson Education-
M.A.Mazidi.