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Old 09-26-2015, 01:30 PM   #2089 (permalink)
thingstodo
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Quote:
Originally Posted by e*clipse View Post
Anyway, as shown in the drawings, one phase leg of the 3 phase motor will have current flowing through it.
I missed this part. Where is that?

The second drawing shows an inductor, but it does not appear to be part of the motor

The third drawing shows the bridge going direct to the pack - and one motor lead. No connection to a second motor lead = no current?

I guess it would help if I READ the patent instead of ASSUMING ...

Using C phase positive transistor would, in my opinion, be a version of a 'bad-boy' charger. That was what I was talking about, which is not what you guys were talking about - sorry

Using B or A or perhaps both positive transistors would perform a boost of sorts through one or two phases of the motor ... I get it!

Quote:
Here in Norway we have 3-phase 400v, so that would make for a supercharger if 3-phase could be used - all built into the inverter without much extra cost.

Charging a 6-800v batterypack with decent range would take some time with a regular charget - not to mention the price tag on a charger of that scale.

If the controller can handle the charging too - that would be a great leap forward in DIY EV.

- Daniel
I'm pretty confident that using C phase positive transistor only would give you charging into the 550V range. It could be a bit of a challenge to cool that one transistor, since it is generating all of the heat. But there is no inductor, so no boost, and some timing or detection may be required to get the batteries a consistent charging voltage/current.

For the boost charger, with no smoothing caps on the supply side ...
- simple - boost without checking voltage and have the batteries charge faster when the 'lumpy' voltage input is higher and slower when the 'lumpy' voltage is lower?
- more complicated programming - vary the length of each boost pulse to allow only a set value of amp-seconds through. A higher voltage gets a shorter pulse, a lower voltage gets a longer pulse .. up to a certain maximum.
- more complicated hardware - detect zero crossing of each phase before the rectifier. That would give you a good idea what the voltage is on the terminals (or you could add a fast-ish A/D channel). So you could time the start of charging boost pulse and length of pulse to get the output boost/output voltage you are looking for .. maybe.

Characterizing the motor and getting pretty darned accurate values would be important for the last one. Not so important for the other two.
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