# 300VDC to 13.7vdc Regulator. HIGH AMPERAGE

Discussion in 'The Projects Forum' started by mpineda1010, Jan 29, 2016.

1. ### mpineda1010 Thread Starter New Member

Jan 29, 2016
16
0
Hello Everyone, First and foremost Thank you in advance to all those who take the time to read this post. I am new to this forum and I am trying to learn as much as possible about electricity.

I need help with a schematic for a voltage regulator that would take up to 300VDC/VAC.(whatever is easier AC or DC as I have a 3 phase bridge rectifier already) and make a conversion to a 12VDC Charge Controller.

I have a DC motor I am working with that when spun generates up to 300Volts. I would like to have that energy created by the motor and then converted to a usable higher amperage 12VDC. What I am trying to do is have a 12volt Batter bank that would power up my inverter. The incoming Voltage may not constantly be at this voltage and may fluctuate either up or down, but I want my output to be at a constant level to charge a battery bank.

a video below has the same motors I have and am working with.

2. ### AnalogKid Distinguished Member

Aug 1, 2013
4,705
1,300
You forgot to tell us the HIGH AMPERAGE.

ak

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3. ### mpineda1010 Thread Starter New Member

Jan 29, 2016
16
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Hello AK. Is what am trying to do even possible? Sorry about the all caps.

4. ### SLK001 Well-Known Member

Nov 29, 2011
852
243
What is HIGH AMPERAGE to you? 2 amps? 20 amps? 200 amps?

The only way I see to do this is with some type of buck convertor. You won't be able to make the jump to hyperspace (convert 300VDC to 13.7VDC) with standard electronics.

5. ### Lestraveled Well-Known Member

May 19, 2014
1,957
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ummm. I think that is exactly how you would convert 300Vdc to 13.7Vdc.

6. ### mpineda1010 Thread Starter New Member

Jan 29, 2016
16
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100amps would be ideal. But I haven't really been able to test the amps on the voltage generated by the motor. Basically I would want enough to charge 4 200ah 12v deep cycle batteries.

A question I have is this. If I do a buck converter. Would I loose some of that energy generated by the dc motor? From my understanding and please correct me if am wrong. It is possible to come down on voltage while increasing the amperage?

I had a mppt concept in mind.

Again am no expert on the matter but am becoming an enthusiastic about the topic and want to learn more.

Thanks all for the help.

Melvin.

7. ### ScottWang Moderator

Aug 23, 2012
4,933
777
The power consumption as:
P = V*I = (300 Vdc - 13.7 Vdc)*100 A = 286.3 Vdc*100 A = 28630 Watts
The input voltages is to high, you have to using some more regulars to in series and mosfet or IGBT to do that.

8. ### SLK001 Well-Known Member

Nov 29, 2011
852
243
I meant standard linear voltage regulator type circuits (types a beginner would use).

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9. ### David Knight New Member

Aug 4, 2015
26
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for large voltage drops and high current, a linear regulator is too inefficient and would require a very large heatsink.

10. ### David Knight New Member

Aug 4, 2015
26
5
300V in to 12V out is a large conversion ratio.

A dc-dc converter with a transformer will work better. Consider using a forward converter.

For high current, you may consider interleaved converters, or using multiple converters in parallel, if they are designed to provide an equal share of current to the load.

11. ### David Knight New Member

Aug 4, 2015
26
5

Lots of questions here.
A buck converter does step the voltage down, and can provide more current than it accepts. This is basic conversation of power. power in = power out. VinIn=VoutIout.

Do you mean 300V in, 12V out @ 100A?

What's the range of the motor voltage output? Up to 300V isn't a very tight spec. Is it always 300V, or 100V-300V, or 50V-300V?

12. ### Dodgydave AAC Fanatic!

Jun 22, 2012
5,159
772
If your generator gives out 300V AC, you're better using a transformer to drop it down to 15V ac for your charger, less power wasting.

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13. ### mpineda1010 Thread Starter New Member

Jan 29, 2016
16
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The generator goes Up to 300v depending on the rpms. The input voltage would be a range of 100v up to 300vac.

14. ### mpineda1010 Thread Starter New Member

Jan 29, 2016
16
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Basically is a summary I am looking to build a voltage regulator that I could connect to my charge controller.

15. ### William Heacock New Member

Oct 30, 2015
3
3
Hi all,
The motor placard reads 1/2 HP at 1650 rpm, 1 phase 205v and 4.1amps. This info tells us the motor output is 373 watts. It also implies an efficiency of motor is about 45% (not that great)
The motor output should be used as a best case. So if it measured 300 volts the current maximum for your design should be limited to around 1 1/4 amps for the input side of the conversion circuit. This falls into line with the measurements made
Without knowing what the input circuit removed from the motor was doing, it's a guess as to the winding output. An oscilloscope would be a big help in figuring it out. The frequency could be a factor.
I think a safe assumption is that it is AC power being generated since there is no commutator, therefore a simple conversion circuit would a step down transformer with a rectifier on the secondary. Then regulate the voltage to 13.7VDC @30amps Max
Does this make sense?

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16. ### mpineda1010 Thread Starter New Member

Jan 29, 2016
16
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Makes plenty of sense.

17. ### AnalogKid Distinguished Member

Aug 1, 2013
4,705
1,300
You missed the point. How can we discuss a power supply without knowing its output current, especially if you think the output current is so important that it is in the title? Think twice, write once.

ak

18. ### AnalogKid Distinguished Member

Aug 1, 2013
4,705
1,300
Vicor and SynQor make fully isolated DC/DC converter "bricks" that can be paralleled to meet this requirement with a 300 Vdc input.

ak

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19. ### #12 Expert

Nov 30, 2010
16,705
7,355
I recognize that motor. It comes with a 3 phase Variable Frequency Drive inside the end cap. The driver fails in about 3 years and the mechanical parts are as good as new. That does not make it a good thing to charge 12V batteries with, and you are not going to get 3800 watts out of it! The wires will melt before it does that. The fact that you found a motor does not make it practical for a battery charger. If you found an elephant, would you try to use it for a vacuum cleaner?

It frustrates me to see people pick up just any old piece of discarded junk and try to get a bunch of nerds to make it to do what it wasn't designed for. This is a rather extreme case of, "not right for the job". Go get the alternator out of a junk car if you want a hundred amps to charge batteries with.

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20. ### SLK001 Well-Known Member

Nov 29, 2011
852
243
Hey, that's a great idea!! Do you mind if I patent that?

Seriously, conservation of energy says that you can't get more energy out of a system than you put in. As a starting point, find out what it takes to power your motor. Then take 80% of that as your motor's capability as a generator.

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