DESIGN AND IMPLEMENTATION OF

3- PHASE CYCLO-CONVERTER FOR HIGH

FREQUENCY APPLICATIONS

PRESENTED BY

ASHOK KUMAR C U* THAMARAICHSELVAN.S

Mr. MUSTHAFA. P M.E (GUIDE)

ASSISTANT PROFESSOR

DEAPARTMENT OF ELECTRICAL AND ELECTRONICS

ENGINEERING (EEE)

VEL TECH MULTI TECH DR. RR AND DR.SR ENGINEERING

COLLEGE, CHENNAI-600062

ABSTRACT

• Designing a 3 phase cyclo-converter using H-bridge inverterwhich could generate the constant voltage at load (RLC load)and it can be regulate and maintain

• Switching device- MOSFET as an advantage of high switchingspeed over IGBT and it can be operate at high frequencyapplications

• Purpose – To convert the low frequency Alternatingcurrent(LFAC) to high frequency alternating current(HFAC).

• Single input multiple output(SIMO) system is used withoutany switching loss

• This design system can be operate at unity power factor

• To verify the design – power circuit-MATLAB simulink andcontrol circuit- Keil software using Microchip PIC16F877A

BLOCK DIAGRAM

AC VOLTAGE SOURCE

DIODE RECTIFIER

H-BRIDGE INVERTER

RLC LOAD

TRIGGERING CIRCUIT

Cyclo-Converter Circuit- Existing Topologies

Cyclo-Converter circuit- Proposed Topologies

Comparison Between Proposed And Existing System

S.NO PROPOSED SYSTEM EXISTING SYSTEM

1 Single input multi output (SIMO) isused with wide range of frequencywithout switching losses

Single input single output(SISO) system isused

2 Obtain a constant voltage and it canbe regulate and maintain

Obtain a constant voltage but cannot beregulate and maintain

3 Less physical damage More physical damage

4 RLC load is used Inductive load is used

5 harmonic distortion is 0.2459% Harmonic distortion is 0.72%

6 Cost is less Cost is more

7 MOSFET with pair of diode is used to reduced the switching loss

IGBT is used which results is appreciable switching loss

8 Operate at Unity power factor Power Factor may be vary (0.85 to 0.95)

Modules Involved

Hardware Required:

LC filter Circuit Diode Rectifier H-bridge Series Resonant Inverter RLC Load MOSFET ( 6 nos) LED

Software Used :

MATLAB/SIMULINK software Keil μVersion 4

Operation Filter Circuit- To remove the ripple from the AC source and fedto the rectifier

Diode Rectifier- RC snubber circuit which eliminates noisefrom the input signal and also converts the AC source to DCsource

H-bridge inverter- A series resonant inverter for determiningthe resonant Frequency at RLC load and converts DC source toAC source

Switching Circuit: MOSFET is used instead of IGBT. MOSFEThas an advantage of High Switching speed and it can be used inhigh frequency applications

Design Specifications

1. Input source Specifications

• Input Voltage(Vs ) = 110V

• Frequency ( f ) = 50HZ

• Delay angle (α ) = 0

2.LC Filter Circuit Specifications

Inductor filter = 1mH

Capacitor filter = 2μF

Purpose : To remove the unwanted noise andripple from the input source

3. Diode Rectifier Specification

Type of Rectifier : Centre Tapped DiodeRectifier

Power Electronics Device : DiodeForward Voltage = 1VNo. of Diode = 4

Purpose : Snubber Circuit – To reduce the total Harmonic distortion (THD) and

convert AC to DC source

4. H- Bridge Inverter Specifications

Design of MOSFET

Topologies (N) =( 2 * n ) + 2Wheren - output inverter at nth stageFor n=2

N = ( 2 *2 ) +2 = 6No. of MOSFET used = 6

Purpose : Switching Pulse Depends upon Duty Cycle of theSystem

5. RLC Load Specifications:

Resistance (Ro ) = 9.5 Ω

Inductance ( Lo ) = 60 μH

Capacitor ( Co ) = 0.45 μF

Purpose : To obtain the Resonant Frequency at the load

Design Calculations Steps

Step 1: To determine the DC voltage link (Vdc )

Step 2: To determine the duty cycle of switchingcircuit for 3 branches and also design thelogical representation of switching circuit

Step 3: Compute the resonant frequency (fo) and Time(T0)

Step 4: Determine the output voltage(V0 ) andcurrent(I0 )

Step 5: Determine the power factor ( cosθ )

Step 1 :To find the DC voltage link (Vdc )

Vm – Input Peak Voltage = √2 Vs = 155V

Vdc = (2 √2 Vs )/ π = 140V

Step 2 : Determine the Duty Cycle of switchingcircuit and also logical Design of switchingcircuit

Duty Cycle (§ )= Ton/ T

T= Total Time = Ton + Toff

Ton= On time in ms ; Toff = off time in ms

BRANCH 1 : Q1 , Q2 are in the same branch

%501002

1

211)()(

;100)(

1)(

1)(

DutyCycle

msoffTonTT

T

onTDutyCycle

msoffT

msonT

onQuantisati

Q2 Must be Complement of Q1

BRANCH 2 : Q3 , Q4 are in the same branch

%401002

8.0

22.18.0)()(

;100)(

2.1)(

8.0)(

DutyCycle

msoffTonTT

T

onTDutyCycle

msoffT

msonT

Q3 Must be Complement of Q4

BRANCH 3 : Q5 , Q6 are in same branch

%201002

4.0

26.14.0)()(

;100)(

6.1)(

4.0)(

DutyCycle

msoffTonTT

T

onTDutyCycle

msoffT

msonT

Q5 Must be Complement of Q6

Step 3: Compute the Resonant Frequency ( fo )and Time(T ):

sec/3^10192

6^1045.06^1060

1

;1

;1

tanRe_tan_

_

rad

LC

CL

ceaccapacitivecereacinductive

resonanceAt

sec30000

11

302

3^10192

2

foT

Time

KHzfo

frequency

Step 4: To determine output Voltage( Vo ) and outputcurrent (Io )

;2)^1

(2^

);1

(

;

:_

110

2

)02sin(01110

π2

α)Sin(2

π

α1VV

_

SO

CLRZ

CLjRZ

Z

VoIo

MeasuredCurrent

VVo

voltageOutput

AIoCurrent

Z

Z

C

C

L

L

FCHLR

125.9

110)(

5.9)(

;2)^57.1152.11(2^5.9

;57.111

;6^1045.0502

11

;52.11

;6^1060502

45.0;60;5.9

Design parameters

Inductive Reactance

Capacitive reactance

Impedance

Step 5: To determine the power factor ( cos θ )

)(1_

1)3015.0cos(cos_

;3015.05.9

05.0tan

5.9

05.057.1152.11

tan

unityfactorpower

factorpower

R

X

R

X

MATLAB/SIMULINK SIMULATION RESULT

1. PROPOSED CYCLO-CONVERTER CIRCUIT

2. DESIGN LOGIC DIAGRAM OF SWITCHING CIRCUIT

3. INPUT VOLTAGE AND CURRENT

INPUT VOLTAGE

INPUT CURRENT

4. DC VOLTAGE LINK

5. SWITCHING PULSE OF MOSFET

6. OUTPUT VOLTAGE AND CURRENT AT 50% DUTY CYCLE

OUTPUT VOLTAGE

OUTPUT CURRENT

7. Output Voltage and Current at 40% duty cycle

OUTPUT VOLTAGE

OUTPUT CURRENT

8. Overall Simulation Result

Photograph of Hardware module

Applications

High Frequency Applications:

• High power low speed AC motor drive

• Metal heat treatment

• Thermal treatment process such as forging and casting

• Electromagnetic induction based plasma generationprocess

• High-speed dissolution process for the new materialsand melting process of semiconductor manufacturing

High frequency Industrial Applications

• Induction Heating purpose

• Supply power to Aircraft Engine

• Gearless cement mills,

• Steel rolling mills,

• Ore grinding mills,

• Pumps and compressors,

• Mine winders

Conclusion

In that system ,we describes how to design

and implement an 3 phase cycloconverter.

The main objective is convert To low

Frequency AC input into High Frequency AC

output. The main feature of the inverter is to

reduced switch count and lightweight. To

overcome that voltage spike and high losses,

we are using MOSFET as switching devices.

Future Enhancement

• By using Cycloconverter, we can develop usinginverter named as Cyclo-inverter for industrialpurpose which can be design and simulateusing PROTEUS 7.9 software.

• By specifying a multi-output series-resonanthigh frequency inverter, an inverter isobtained fulfilling the requirements.

Literature Survey

• V.K Mehta and R. Mehta, Principles of Electronics(MulticolorIllustrative Edition),Copy right-2004,2003,2002, S. Chand and CompanyLtd, New Delhi.

• M. H. Rashid, Power Electronics Circuits, Devices and Application 6thedition, Copy right 2009, Prentice Hall, Inc Upper Saddle River, NJ.

• A. K. Chattopadhyay, „„Cycloconverters and cycloconverter-feddrives—A Review.’’ J. Indian Inst. Sci.

• T. J. Rao, „„Simplified control electronics for a practicalcycloconverter.’’ Int. J. Electronics

• B. R. Pelly, Thyristor Phase-Controlled Converters andCycloconverters, John Wiley, New York, 1971

• J. Davies and P. Simpson, Induction Heating Handbook. New YorkMcCraw Hill (U.K.) Limited.

• Vineeta Agarwal and Sachin Nema, “Resonant AC to AC”, ISIE, 20-23June, 2005, Vol.2, Dubrovnik, Croatia