I'm having trouble with the boost converter I made. Everything works properly with a large resistance value ;however, once I change the load resistor to a small value the system stops boosting the voltage and the output is only a fraction of the input voltage. Anything below 20 Ohms and the system stops working. I'm following this guide and using the same setup as this guide:
I've looked into why this is happening and I can't seem to find any information regarding the loads impact on the boost converter.
Im using an IRF530A MOSFET, 22uH inductor, schottky diode and a 150uF capacitor. Any help is VERY APPRECIATED.
Please read the first post in any forum entitled how to use this forum. http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Please a complete diagram, not a Fritzy image or a simulator circuit .
What model Arduino are you using?
Check the specs of the IRF530A, is it a logic level input MOSFET?
The article uses a logic level mosfet (IRLI640), while you used a fet (IRF540) that can't be fully turned 'on' with Arduino's 5volt logic.
Details matter.
Leo..
Don't know. There might be more wrong.
Might be the wrong schottky diode, or the wrong type of capacitor, or your wires are too long/thin, or you use a breadboad, or your PWM frequency is too low (you used a 22uH inductor instead of 330uH), etc.
It's not easy to make a good buck or boost converter.
Leo..
I would start by copying a known good circuit - down to the very parts they used, or at least something that's very close in specifications (in which case you will have to understand the circuit deeply enough to know which parameters to look at exactly, as not all matters as much).
Then it being a boost converter, solder it on a piece of perfboard to make sure you have good connections.
Analog circuits such as these are much harder to get right than digital circuits, as things such as component placement may make a big difference.
Sorry for the slow response... I ordered a few new components, such as a IRLI640, a bigger inductor (330uH) and a higher rated voltage diode (MBR10100GOS). I've already seen a huge improvement with the new MOSFETS. I was able to easly step the voltage up from 2.97 V to 50 V and rising (I shut the power off as the rating of the Capacitor was exceeded, the duty cycle was set at a fixed 200 value) using a 20k resistor as the load. I'm using a DC regulated Power supply as the input. The system I'm designing is expecting a high current of around 6A max. But for the testing i'm using a much lower input current. However, the same problem still occurs when I connect a smaller load. The 2.97 volts is only able to be stepped up to 3.15V. I've tried messing with the inductance, frequency (using a due with a gate driver at 300Khz) and capacitance. (I realize you probably can't see much from my setup). (I've tried using both the Uno and Due)
With high frequency power supplies, layout is important, so try grouping your components closer with shorter wiring, it may help the situation.
Protoboard is not the best environment for this type of subject.
I can only see one resistor where the voltage feedback divider should be, R1 and R2.
Also no 10K, R3 in your layout.
It is very hard to see your MOSFET connections.
Can you post another pic from a different angle so we can see the DUE and the MOSFET connections?
Can you please post a drawing of your circuit for us please, if you reverse engineer what you have on your protoboard it my help check your circuit.
Double check the MOSFET pinouts as well as the Schottky.
The originator has only supplied test figures for under 300mA output current.
I doubt if you will get 6A output, especially in protoboard setup.
No performance figures for higher loads.
If you read the article, there is always quotes of output voltages, but no output current of any serious value.
From the picture, it looks like an air core inductor. The switching frequency of the circuit is quite low (62kHz). More usual would be ferrite core inductor, however, I can’t say if that makes any difference.
I usually buy these things ready made, however I did make one for a Nixie clock power supply which could produce up to 350volts. It used a 555 timer based design and not controlled directly fro an Arduino.
6A output at 50V that would mean 300W of power output. Assuming 80% efficiency (the good ones reach just over 90%) that would also mean a 75A current on the input side. Are you serious about this? I'm sure there are better ways to produce such a power supply!
Your solderless breadboard will end up as a smoking pile of molten plastic way before that.
What is powering the boost converter, and more importantly, what is the current capability of the source.
Boost converters can draw hi currents for short periods of time , and require something that resembles a voltage source, like a battery or a decent power supply.
You have no hope of building a boost converter to produce 50V @ 6 A.
Ok to clarify the 50Volts was just for test purposes, the system is suppose to step up .5V to 5V with a max output current of 6A so a 30W system (10A Input Max). I built a Simulink model for the system and after experimenting I believe that the reason it is unable to step up the voltage at a smaller resistance value, is due to the lack of current in the system. Thanks for the help.
The input power is coming from a small wind turbine that produces 10A and 3V at the rated power. I was hoping to design the system to produce a constant 5V output as soon as possible. I bought a small boost converter to power the Arduino that turns on at .5V. So I was hoping to start outputting 5V from the boost converter I'm designing at around the same .5 Volts. But that is starting to seem unlikely.
heilander4:
So do you think that, would lead to the boost converter to stop working with a smaller load?
If the resistor is smaller that is a larger load, not a smaller one.
You can't make a boost converter on solderless bread board, it is folly to try. It might work with small currents but anything substantial simply will not work. You require a properly designed PCB.
I have managed many specialist engineers, and have yet to meet one who can design a working switch mode power supply in less than three iterations of PCB. The problems are keeping it stable over the range of all possible current draws. Your project is doomed to failure. Especially as you don't seem to even have an oscilloscope.
I have an Oscilloscope , and the goal was to test a simple prototype boost converter on a breadboard for simplicity. After that the next step was to implement the design on a PCB. I was just trying to understand why the boost converter was not working with a smaller resistance value.
