A PROJECT ON

PRSENTED BY: NAME EXAM SEAT NO.KIRTIKUMAR PATIL W3094051SAGAR PATIL W3094052GOPAL PAWASKAR W3094053

BUCK-BOOST CONVERTER

GUIDED BY: DR.D.S.MORE

INTRODUCTION

Buck-boost converter operates on dc supply

Buck operationBoost operationDuty ratio of control signal defines

its operation

CONTROL CIRCUIT

OPERATION OF CONTROL CIRCUIT

To drive the mosfet op-amp based circuit is designed

Op-amp(A) is used as an integratorOp-amp(B) and op-amp(c) is used as a

comparatorTransistor 2N5294 is used as a switch to provide

control signalFrequency and duty ratio of output signal can be

controlled by using potentiometer in this circuit

Output waveform of Op-amp(A)

Output waveform of Op-amp(B)

Output waveform of control circuit

POWER CIRCUIT

OPERATION OF POWER CIRCUITStep 1: when mosfet is ON

Voltage across inductor L is equal to V

(source voltage)

Step 2: when mosfet is OFF

Voltage across inductor L is equal to Vo (in reverse direction)

Here output voltage developed across load is Vo

Step 3: When mosfet is ON in next cycleLoad is isolated from voltage sourceIn this case charged capacitor across load

will maitain voltage across load

DUTY RATIODuty ratio(D) is defined as Ton/T here, Ton=ON time T=time period of gate

signal D=Ton/T Ton=DT T=Ton+Toff Toff=T-Ton Toff=(1-D)T

VOLTAGE ACROSS INDUCTORWhen mosfet is ON, voltage across inductor is

equal to source voltage(V).When mosfet is OFF, voltage across inductor is

equal to output voltage(Vo)As average voltage across inductor is zero Hence, V*D*T=Vo*(1-D)*T Vo=V* D 1-D

Vo=V* D 1-DThis equation shows that output voltage

depends on duty ratio(D) For buck operation D=0 to 0.5 For boost operation D=0.5 to 1

APPLICATIONSUsed in many industrial applications

such as subway cars, trolley buses, battery operated vehicles, battery charging etc.

To provide smooth control on output, high efficiency, fast response and regeneration.

To provide efficient control on dc motor operation

To provide long life and less maintenance due to absence of moving parts.

THANK YOU!