Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

arnolde · 06-02-2009, 03:19 AM

Hi,

I use a standard industry 3-phase 400V inverter for a standard industry 400V 3-phase motor :-) 400V times sqrt(2) is 560 so thats the DC voltage on the DC circuit. luckily 500V is sufficient, maybe even 450V would have been enough, but high voltage = low current and higher possible motor rpm.

Thanks a lot for the links, I'll order all the parts today and hopefully tomorrow I can start wiring things up. I cant wait to show all the German smart-asses on the electronics forum how easy it is to do what they say is "impossible for under 2000 EUR" or even "impossible even just to draft a circuit for less than 500 EUR" - harharhar :-) But I owe it to you, I had similar ideas but since you've already proved it will work in principle, that gives me the extra motivation to actually do it. Thanks a lot for the pioneer work!

I hope to get all components from stock. I use rs-components and Farnell for my electronics orders. So even with orders from the USA, it's here in 3 days :-)

You say you "originally had a shunt" for current measurung? What do you use now?

Take a look at this: http://www.st.com/stonline/products/...99/uc3842b.pdf see figure 19 on page 9, looks rather simple to me? Maybe not quite as simple as a 555 circuit but at least its self-regulating!

Consider safety issues with using just a µC for the PWM. Imagine your program locks up (bug in software, or even a hardware problem with the µC, or overheating) and leaves the duty cycle "ON". It will roast your batteries. You need to implement several safety features to prevent that from happening.

06-02-2009, 03:19 AM	#75 (permalink)
arnolde EcoModding Lurker Join Date: May 2009 Location: Germany Posts: 21 Thanks: 0 Thanked 0 Times in 0 Posts	Hi, I use a standard industry 3-phase 400V inverter for a standard industry 400V 3-phase motor :-) 400V times sqrt(2) is 560 so thats the DC voltage on the DC circuit. luckily 500V is sufficient, maybe even 450V would have been enough, but high voltage = low current and higher possible motor rpm. Thanks a lot for the links, I'll order all the parts today and hopefully tomorrow I can start wiring things up. I cant wait to show all the German smart-asses on the electronics forum how easy it is to do what they say is "impossible for under 2000 EUR" or even "impossible even just to draft a circuit for less than 500 EUR" - harharhar :-) But I owe it to you, I had similar ideas but since you've already proved it will work in principle, that gives me the extra motivation to actually do it. Thanks a lot for the pioneer work! I hope to get all components from stock. I use rs-components and Farnell for my electronics orders. So even with orders from the USA, it's here in 3 days :-) You say you "originally had a shunt" for current measurung? What do you use now? Take a look at this: http://www.st.com/stonline/products/...99/uc3842b.pdf see figure 19 on page 9, looks rather simple to me? Maybe not quite as simple as a 555 circuit but at least its self-regulating! Consider safety issues with using just a µC for the PWM. Imagine your program locks up (bug in software, or even a hardware problem with the µC, or overheating) and leaves the duty cycle "ON". It will roast your batteries. You need to implement several safety features to prevent that from happening.