http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=955457&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D955457
Economical in $$$ ? Difficult to say.
Efficiency can be increased but at quite some cost.
I know a type of 'hybrid Lundell alternator" where the field is improved by permanent magnet inserts. These alternators are capable of 10+ kW (vs. the 6 kW stated in the IEEE paper).
Salient pole generators are quite sensible regarding high RPMs - especially regarding 'automotive operating conditions'. Thus - even with higher efficiency numbers - the question is whether they will have the same life time. Which I doubt.
Thank you Sir for your answer,
Please can you share the link where I can find these type of 'hybrid Lundell alternators'? The main issue is that we cannot expect good performance from salient pole generators at high speeds, since they lack robustness as compared to Lundell alternators.
Hello,
it's me a pleasure. Be aware that this is patented technology. Thus I'll give you the links to FPO:
US 6867530 B2 http://www.freepatentsonline.com/6867530.html
US20040119357 A1 http://www.freepatentsonline.com/y2004/0119357.html
Should be available on google as well. And there should also be enough keywords references etc. to continue with further search.
Regards
Thank you so much Sir!
One more question Sir,
If the Switch mode regulation method implies DC to DC voltage transformation by varying the duty cycles of the switch, then how do we extract improved power from the output as compared to the regulator used in the conventional Lundell alternator? Is this because the resistance heat losses in the conventional regulator are curbed by this new regulator?
Can this method of switch mode rectification be used in the electrically excited salient pole generators, since it is known to improve efficiency at higher speeds and it may nullify the drawback of the EESPG?
Hi, I had only a short glimpse into a "switch mode rectification" document last night.
What I just learned from "dspace.mit.edu/openaccess-disseminate/1721.1/86964":
(I am E/E - thus "switched mode 'something'" could denote a lot of things...
In the paper referred above they eliminate (most of) the power loss due to conduction losses of the low-side diodes (some 1-2 V multiplied with the load current - maiking it 80-160 W for the low-side of a 12 V/80 A (roundabout 1 kW) alternator).
Calculating the other way round: With standard diode bridge rectification, you'll have 2 * 80..160 W losses per kW - resulting in efficiency figures of 66 - 83 % for nominal current. Minus the excitation current - some other percents of the current generated.
The rectification method does not rely on the type of generator: if your salient pole machine generates a 3-phase AC output, the switched mode rectifier is applicable to this as well.
BTW: the efficiency improvements of this switched mode rectifier are hardly depending on engine speed. They directly correlate with load: the forward voltage of the diodes increases with load current. Thus the power loss in the diodes increases by more than a simple factor when load current increases.
If you have another switch mode scheme in mind: please provide link or document (English or German please).
Regards
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