[SOLVED] How to Choose a Boost-Buck Converter

[Creighton]

Right now I'm trying to design a hybrid charge controller for wind and solar energy and I'm going to need about 4 DC-DC charge controllers to complete my design. However, I have very little experience with power electronics and I don't know where to start looking for them. I need to find a DC/DC Buck-Boost converter that can take an input range from 1-15V and can handle around 30W of power. I also need to be able to control it externally with a microcontroller using PWM signals so that I can control the output voltage in real time. Can anybody direct me towards a seller of a something like this? I'd also appreciate if someone could send me a link that explains how to control a buck-boost converter with PWM. I've been looking into a lot of research articles but I don't really understand how it would work. Thanks for the help.

 

[Creighton]

I've another question. Are there DC/DC Converters that are in general made for external control form a microcontroller? Or are most manufactured ones made into ICs?

 

[bharti thakur]

My query is similar to your's?....did u get any such ic which could be controlled externally from PWM...? and also boost converter for 40-24 volt input with 24 volt output.

 

[Tahmid]

Right now I'm trying to design a hybrid charge controller for wind and solar energy and I'm going to need about 4 DC-DC charge controllers to complete my design. However, I have very little experience with power electronics and I don't know where to start looking for them. I need to find a DC/DC Buck-Boost converter that can take an input range from 1-15V and can handle around 30W of power. I also need to be able to control it externally with a microcontroller using PWM signals so that I can control the output voltage in real time. Can anybody direct me towards a seller of a something like this? I'd also appreciate if someone could send me a link that explains how to control a buck-boost converter with PWM. I've been looking into a lot of research articles but I don't really understand how it would work. Thanks for the help.

Why don't you make your own buck-boost converter? Then, you can control it with the microcontroller. If the PWM is generated by the micro, you can control output voltage in the software. If you use a PWM chip, you can control the output voltage by using feedback that is controlled by the microcontroller.

You could use a buck-boost converter to step up/down to 5V. You would need very little current for the micro. Then, you can generate as much current as you need from the buck-boost stage controlled by the micro.

Hope this helps.
Tahmid.

---------- Post added at 12:21 ---------- Previous post was at 12:20 ----------

I've another question. Are there DC/DC Converters that are in general made for external control form a microcontroller? Or are most manufactured ones made into ICs?

Many/most PWM ICs used for such converters have a feedback input or an error amplifier. You can control these with the microcontroller to control the output voltage.

Hope this helps.
Tahmid.

---------- Post added at 12:24 ---------- Previous post was at 12:21 ----------

This is also a very nice chip for your use:

LTC3115-1: LTC3115-1 - 40V, 2A Synchronous Buck-Boost DC/DC Converter - Linear Technology

You can control the feedback via a microcontroller.

But it's input is from 2.7V.

 

[Creighton]

Thank you for the suggestion. Here's a more accurate description of my problem. I'm working on an undergraduate design project which is to design a hybrid power management system. I need to use a few DC/DC converters to convert the power from an 1.8V 16A solar panel array up to about 14V in order to charge a 12V 9AH Lead Acid Battery. I need to be able to control the DC-DC output voltage because if I'm going to charge the battery efficiently I'm going to need to be able to actively adapt the voltage and current to meet the battery's demands. I want to use a pre-made converter because I only have 6 weeks left to finish the project and I'm afraid I'll run out of time. I'd be happy to use the the converter from Linear but I don't know a single thing about control theory - I haven't taken that course yet. Could you explain how that's done or provide a link to an article/tutorial on it?