Microcontroller Based Power Converter

forestevanescentΗλεκτρονική - Συσκευές

2 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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Microcontroller Based Power Converter

Group 12

Keith
Kocek

Ankit

Gupta

12/02/2011

Introduction


Converts an input voltage to a specific output
voltage



Operates without an external power source



Expandable and modular design


Features


Digitally Programmable DC
-
DC converter



Programmable current limit option



Wide range of input with Buck/Boost topology



Externally controllable


Via Reference
V
oltage

DC
-
DC Voltage Converter

Microcontroller

UI/UO

Vin Sensor

V/I out
Sensor

Vin
-
5V

Vin(6
-
33V)
Protection

FB
network

Vin
-
Variable
Vout

5V
-
31V

2 lines

5 lines

10 lines

On/Off

Relay

High
-
Level Diagram

System Overview


Hardware:


V
in
-
Variable
V
out

(Buck/Boost converter)


V
in
-
7V Buck/Boost Converter


5
-
30V DC/DC Converter


Feedback Network (Digital Potentiometers)


Current Sensor/Relays



Software:

--

Microcontroller (
Arduino

Nano)

--

LCD Screen/Keypad Interface

--

Voltage Sensor(In/Out)





Buck/Boost Converter (LT 3789)


Steps Up/Down Voltage


Wide V
in

Range: 4V to 38V


1% Output Voltage Accuracy

7
V Buck/Boost Converter (LT 3343)


Powers the Microcontroller, Relay




DC/DC Converter(LT 1316)


Boost Topology


Outputs 30V for Feedback Network

Current Sensor/Relay


Dual Operational Amplifier (LM 2904)


Utilizes series resistor to measure current


ON/OFF Relay


Feedback Network


Two Digital Potentiometers (AD 5290)


100 k
-
ohm


3
-
wire Serial Peripheral Interface


256 bit resolution



Digital control of feedback


Microcontroller (
Arduino

Nano)


Recommended Input Voltage: 7
-
12 V


Powered by Mini
-
B USB or
7
V supply


14


Digital I/0 Pins ( 6 provide PWM output)


8


Analog Input Pins


SPI Communication Supported


LCD Screen/Pushbuttons


Lumex

S01602D


16x2 Character Display


8 Data Bits


Pushbuttons


6

buttons


Allows user interaction

Software


Resistive Divider Network


Displaying to the LCD Screen


User Input/Visual Output


START Button


Feedback Network


Testing Procedure


V
in

Protection


Lock
-
out Reverse Voltage


Block Voltage greater than
33V


Vin fused to protect Vin source


V
in
/
V
out

Sensor


Vin/
Vout

measurement
should be correct


Microcontroller


It should operate the circuit.


Output to
LCD


Set
FB Network

Testing Procedure


V
in
-
Variable
V
out


V
out

should be
within 1
% of the specified
output range of 1V
-
30V


5
-
30V


V
out

should be
30V
, 1%.


Vin
-
7V


V
out

should be
7V
, 1% over the 6V
-
30V
range.


Buck/Boost
-

6V
in

Boost Region

Buck region

V
in
-
Variable
V
out

Extreme Tests

V
in
-
Variable
V
out

Extreme Tests

Low
-
Low

Low
-
High

High
-
Low

Vin
-
7V Tests

5.5V Input

21V Input

5V
-
30V Tests

5V
-
30V Test

Feedback Network


Adjusted Wiper Resistances


Communication with Two Digital
Potentiometers


N
ot robust with the power supply




Vin Protection

Current Sensor/Relays

0
500
1000
1500
2000
2500
3000
3500
250
500
750
1000
1250
1500
1750
2000
2250
2500
2750
3000
3250
3500
3750
mV

mA

Current Sensor

V
in
/
V
out

Sensor

Why do you need it?


Doesn’t require external power source



Simple two
-
input and two
-
output device



Enables the use of other devices



Save Time. Save Money.

Questions?


Snubbing Circuit


Digital Potentiometers