Friday, December 30, 2011

DC-DC CONVERTER (BUCK)


TITLE: DC-DC CONVERTER (BUCK)

ABSTRACT:
                To design a DC-DC converter circuit to modify 100V dc supply to 10V dc.
This can be obtained best by using a Buck converter circuit; this is because it has a very low power dissipation, and high efficiency.

TASK
1.       Design the circuit using “ Multisim software” to check if you can get the required output.
2.       Draw a circuit diagram of the copper circuit based on HCPL3021 (IC), an IGBT/MOSFET, and one diode: included all other components you require.
3.       Choose appropriate devices and components   .
4.       Prepare an order sheet to purchase the components, assume you will be building 20 converters and that cost is a factor. Detail of order number, price, and supplier are essential .
5.       Draw the layout of the chopper circuit. With components (PCB design).
6.       Write a report explaining your design, costing and PCB design for 20 pieces.

PROCEDURES
1.       CALCULATIONS
I choose my frequency to be 65kHz, ripple 0.5%, load resistor RL = 150-Ω. And given, voltage input is 100-V, and expected voltage output is 10-V.
I am using a Buck converter.
 Duty Cycle, D= vo/vi=10/100=0.1

Lmin=(1-D)/2f.R=((1-0.1))/(2*65k).150=1.0385m

L=10*Lmin=10.39mH


C=(1-D)/8rL =f^2=(1-0.1)/(8*0.005*0.01039*(65000)^2 )=512.8pf

Checking my calculations
r=(1-D)/8CLf^2=(1-0.1)/[8*0.0000005128*0.01039*(65000)^2 ]=0.005=0.5%

        which is correct.


2.       MULTISM DESIGN


The circuit

Oscillator output.
As we can see, the output at CH03 is not stable, so in order to stabilize it we need a voltage regulator. Please check my next blog.

3.       PRINTED CIRCIUT BOARD (PCB) DESIGN




4.       Order sheet (In Malaysian Currency)
Description
Unit price (RM)
ZVN3306F MOSFET
1.20 
1N4007GP DIODE
0.20
INDUCTOR 10 mH
0.30
RESISTOR 150 ohm
0.20
CAPACITOR 512.8 pF
1.50
VERO BOARD(small)
1.50
BOX XU484
2.50
WIRE 1M
6
             TOTAL
13.4

For the 20 pieces will be 13.4x20 =268 RM

5.       CONCLUSION

DC-DC converter is more efficient and effective when converting a DC voltage to a DC voltage, whether reduction or increment. It is simple to design and have few components to assemble and very low power loss.

[Please do comment, :D]

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