nss eng college EEE lab results

download pspice schematics in .sch format

download buck converter circuit fig 

download graph output in xpf format 






1.buck converter vpluse parameters
AIM:

To design and simulate buck converters using PSPICE.

PRINCIPLE:

DC choppers can be used as a switching mode regulation to convert a dc voltage,normally unregulated.The regulation is normally achieved by pulse width modulation at a fixed frequency and switching deviceis normally a power BJT,MOSFET or IGBT.There are four base topologies for switching regulators.In a buck converter,the average output voltage V0 is less than input voltage Vs.Hence name as ‘buck’.It is like a step down chopper.

The circuit operation is divided into two

1. It begins when the switch is turned ‘ON’ at t=0,the input current rises,flows through LC filter and load resistor.

2. It begins with switch switch turning off at t=ts,the freewheeling diode conducts and energy in the induction continues to help current flow through Lf,Cf and load and diode D1.



PROCEDURE:

1. Open the ORCAD CAPTURE IS and click ‘new’.

2. Drag the required blocks from the library and connect them accordingly.

3. Define the values to each components as per the diagram.

4. Save the settings and work and run the circuit.

5. Observe the output at output window.




DESIGN

VS=....... ΔVc =0.025VC f=.....

V0=.......... Ra =Va/Ia Is= KIa

Ia=........ K=Va/Vs ΔIc=.05Ia

ΔI=.1Ia

Lf=Va(Vs-Va)/( ΔIfVs)

Cf= ΔI/Δ Vc8f

Assume linear variation if load current IL during time from t0=0 to t1=kT,we can write

ΔIc/t1 =ΔILt/Kt =ΔVc L= ΔVct/ ΔIcf ton = kT


RESULT:

Designed and simulated Buck converter using PSPICE.

download pspice schematics in .sch format 

download buck converter circuit fig 

download graph output in xpf format

home