Apparent Regulator Failures

[Len Averyt]

The six phase rectifier circuit converts the AC into DC prior to going into the "buck" DC to DC converter

[Charles S Otwell]

This sounds very high tech, also sounds very high priced, what kind of money will be involved if this works out?

[Sledge Hammer]

Let me know what you think. Ideas, questions, etcetera.

PS the test part im using is the following
http://www.diodes.com/datasheets/AP1501.pdf

BTW the entire circuit minus the phase rectifiers is 1/2 the size of a postage stamp.

Since I have a wee bit of experience in designing buck converters (and boost converters) and both Ni-Cad and lead-acid battery chargers, I'll toss in my $0.02 worth:

Lead-acid batteries have their own peculiar charging requirements that impose the necessity of throttling the charge current up, down, off, and on as needed. A typical charging profile consists of trickle-charging the battery up to 11.9 V or so, bulk charging (at a current equal to 0.4 X rated ampacity or less) to 13.8 V and trickle charging up to a maximum of 14.5-14.7 V to reach full charge. While the actual voltages recommended will differ slightly from one battery manufacturer to another, in this application with the widely varying input voltage and ambient temperatures, a variable charge rate is needed.

A design using a buckconverter is a great idea, but there are better choices for the controller than the AP1501. A purpose-designed battery charging IC from TI such as the BQ2031 or UC3909 contains a built-in algorithm for managing the charging currents and -- critically important for long battery life -- built-in temperature compensation for the internal voltage references.

To some degree, the physical sizes of the necessary inductors and capacitors can be minimized by running the switcher at the highest frequency permissible, but bear in mind that efficiency generally goes down with increasing frequency because shorter switching periods make the turn-on and turn-off times of the transistors and diodes more significant. Also, the maximum DC current through the inductor is going to drive the minimum core size you can use before the inductor saturates.

You might ask why I'm not working on a design for it right now, and the short answer is that I am going to be living with dc-dc converter problems at work for the next several weeks, thanks to one of my underachieving colleagues.

Some literature you might find useful:

http://focus.ti.com/lit/an/slua098/slua098.pdf Application note for the UC3909

http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1042,C1031,C1061,P1266,D4135 Application note from Linear Technology that gives a nice, readable and comprehensible introduction to buck converters

http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_VRLA_ChargingMethods.pdf Some basics on battery charging from Panasonic

[Len Averyt]

This sounds very high tech, also sounds very high priced, what kind of money will be involved if this works out?

The total parts cost for my regulator design is less than $20. Once I finalize a schematic and a PC board layout then having the PC boards made could be the higher cost item. I still think that the entire unit will be under $40.

A purpose-designed battery charging IC from TI such as the BQ2031 or UC3909 contains a built-in algorithm for managing the charging currents and -- critically important for long battery life -- built-in temperature compensation for the internal voltage references.

I agree that a manager would be great. Would have to see what the design requirments are.
I'll be releasing a schematic of my prototype unit soon and I'll post a link here
http://www.techknowman.com/Moto/Regulator model.pdf

[Sledge Hammer]

Len, I forgot to mention it earlier, but National Semiconductor has some good on-line design tools under their WebBench section. They require you to register to use them, but they will recommend a design based on your circuit requirements.  I used the PLL design tool to get me out of the ditch when I needed two designs for tuners on very short notice, and the final circuits worked exactly as predicted.

Also, somewhere around here I have a packaged, Excel-based design program for various switcher topologies courtesy of On Semiconductor. IT handles all component value calculations, including the magnetics design. They were handing them out at a seminar, so I don't think it's copy-protected. If you want a copy let me know.

[Curtis_Valk]

Allen, he mentioned beefing up the rectifier circuit, so I imagine it will be DC by the time it gets to the converter.  I also like the idea of the accessory circuit that is separate from the battery.

Curtis

[lragan]

I like the idea of a battery management chip in the design, especially if it can provide overload protection and short-circuit protection.  Don't know if it would need thermal overload protection too, but that might not be such a bad idea, given the environment this circuit lives in.

Len, mabe I am missing something, but my understanding is that the current system has a capacity of 430 watts.  At 13.5 volts, this requires nearly 14 amps.  If you get there by paralleling 3 amp converter chips, it will take five of 'em.  Isn't there another choice that does it "all at once"?

I don't know how much filtering is required at the output.  Apparently the ignition system is electronic, and may be susceptible to high frequency "hash" on the battery line.

Has anyone given any thought to a test bench setup?  It would be nice if we could test designs off the bike, somehow, to work out any difficulties...

Mike, I appreciate the links.  Maybe I can learn something here...

[roboto65]

Uhhhhhhhhhh 40 dollars count me in for one heck I will be the tester LOL

[Sledge Hammer]

I like the idea of a battery management chip in the design, especially if it can provide overload protection and short-circuit protection.  Don't know if it would need thermal overload protection too, but that might not be such a bad idea, given the environment this circuit lives in.

Len, mabe I am missing something, but my understanding is that the current system has a capacity of 430 watts.  At 13.5 volts, this requires nearly 14 amps.  If you get there by paralleling 3 amp converter chips, it will take five of 'em.  Isn't there another choice that does it "all at once"?

I don't know how much filtering is required at the output.  Apparently the ignition system is electronic, and may be susceptible to high frequency "hash" on the battery line.

Has anyone given any thought to a test bench setup?  It would be nice if we could test designs off the bike, somehow, to work out any difficulties...

Mike, I appreciate the links.  Maybe I can learn something here...

Lawrence, you are correct that the circuit would be more manageable by designing for heavier currents rather than paralleling controller chips in a dc-dc converter. Unless you used diode ORing to tie the outputs together after their tap-off points for their feedback loops, you'd likely wind up with a battle of the control loops as each one tried to react independently to control the output voltage. Also the voltage drop across the ORing diodes cuts into your charging headroom and dissipates yet  more heat in the circuit. There are two ways around that. The first is to let the output of the controller IC drive the input to a beefy switch transistor (MOSFETs tend to be your best choices). The other (which I have not yet designed) is a tapped-inductor buck converter, which the Linear Technology engineer addresses in App Note 44, to reduced the amount of current the switch has to carry and thereby also improve the efficiency since you are dissipating less heat in the switch. In fact, those two features could be combined. {CORRECTION: To take advantage of the tapped inductor approach, we'd have to have a lot more voltage headroom, otherwise we'd wind up with the same ~ 1:1 ratio between input current and output current we're saddled with now.)

There are also multi-phase buck converters, which could allow a savvy engineer to cut out the rectifier diodes altogether. Instead, in a three-phase application like this, you do have three controllers, each one operating off a given phase of the alternator. The output of each feeds the same inductor. I have no experience with these, so it would be helpful to consult a real expert on power conversion for the pros and cons of this approach.

I agree with your concern about the high-frequency hash. You'd need some good filtering to keep RF hash from getting into other things on the bike. I also agree that you'd want to do a LOT of testing on the bench before hooking this set-up to your Magna's electrical system. My own "home" lab set-up is at my parents' house. I wonder if my folks would become suspicious if I suddenly started visiting more often? 

BTW, as Terry pointed out to me some time back in another thread, the manual indicates the system is rated for 374 W at 5000 rpm. I think you'd need to design for 30 Ato make sure you had headroom.

Of course, there is no single way of approaching this. If you've got an idea, by all means take a crack at it. It's worthwhile trying different approaches, learning from the shortcomings, and applying the lessons learned. And I can speak firsthand that having any experience at all with dc-dc converters is a big plus on the engineering resume.

[Sledge Hammer]

Incidentally, this subject has also come up recently at work, with a buddy's ZZR1200 having killed its battery last Friday. It was so far gone that we couldn't even push-start the bike.

I was also told by the owner of a Goldwing that the members of his forum have had bad results with the aftermarket R/Rs. When his '87 'Wing's R/R went bad on him, he wound up just buying a new OEM because the cheaper alternatives have the reputation of dying within a weekend of riding. Wonder if there's a market for a bullet-proof regulators?

[Charles S Otwell]

Most of the talk about the regulators has been about over charging,  causing the battery to boil over, what about the ones like mine that just stop charging? I just figured ten years and 35,000 miles it was just time for a few things to start wearing out and breaking. There were no physical sign of damage to the regulator it just quit. I would think that if heat was the culprit the symptons would have been the same as the others (over charging). All this high tech talk just got me wondering what caused mine  to just quit.

[Magnum Magna]

On my friends VFR it blew the 30 amp fuse we replace the fuse then it went wild hot but did not blow the fuse again.  He did not run it for but a few minutes he could smell something was burning up.  No we did not put a no blow fuse in it. 

[L J VFR]

I think I asked this a long time ago when this first thread started, but i will ask again...  Is the regulator/rectifier  "issues"  happening to  all magna's or just a certain year model?     Charles, 10 years and 35000 miles on one regulator is good i would think,  but in "vehicle"/cage years not so good..   My bike is a 2001 model,  anyone have a R/R issue with a newer model bike?  Have they changed the design any??    Just some questions that i keep thinking as i read these post..                                                                                                        The last thing anyone wants to happen is  failure which unfortunately happened to felicia and some others..  I don't want to fix something that isn't broke, however, riding my bike wondering if the R/R  is going to "give up" someday does'nt set well on my stomach...  I would also be up for one of these new designs I suppose...  when needed....

[Sledge Hammer]

Most of the talk about the regulators has been about over charging,  causing the battery to boil over, what about the ones like mine that just stop charging? I just figured ten years and 35,000 miles it was just time for a few things to start wearing out and breaking. There were no physical sign of damage to the regulator it just quit. I would think that if heat was the culprit the symptons would have been the same as the others (over charging). All this high tech talk just got me wondering what caused mine  to just quit.

Eventually, heat will kill any electronic component. It is simply a matter of when. I think Lawrence is probably better qualified to discuss this particular aspect, but as a rule of thumb every 10°C rise in temperature cuts a given component's life span in half. Also, just as with human lifespans, a tiny percentage somehow manage to outlive the rest. Then it becomes a matter of removing and replacing with like item.

[Greg Cothern]

Now that I an sitting in the corner in the fetal position mumbling to my self incoherently!!!!    

You smart folk just let me know when you get it all figured out and how much it will cost me to install one on my Project 96??!!!!