You are here


3 posts / 0 new
Last post
Last seen: 19 hours 4 min ago
VESC BronzeVESC GoldVESC OriginalVESC Silver
Joined: 2016-12-27 20:19
Posts: 207

The VESC 75/300 is now available for purchase. Benjamin is very happy with the final tests and we can so no reason to hold it back any further. The performance is beyond any expectations. If you have projects that require higher output power do not hesitate to pre-order your VESC75/300. This is a limited volume production run of 100 units. First come first served. PCBs will be RED with golden VESC-Logo.

Last seen: 18 hours 43 min ago
VESC FreeVESC Platinum
Joined: 2017-09-22 01:27
Posts: 223

So if I am looking at it right for its power stage it uses these parts:

18x 75v Direct FETs IRF7759L2TRPBF 1.8mOhm  (0.6mOhm per phase)

18x 4.7uF 100V 1210 Ceramic capacitors   (5.2uF @ 18S, 6uF @ 16S per phase)

6x 470uF 80V 16x30mm KZN United Chemi-Con Electrolytic capacitors

9x 0.5mOhm 9W Bourns Current Sense Resistors (0.16mOhm per phase)

3x INA240A1 20V/V (+/-495A measurement range)

3x TI Gate driver

I heard Benjamin in the video saying he is using 75v fets? That seems silly when you could easily support higher voltages by just changing to 100v fets. (obviously this falls outside of the low voltage directive in Europe, but it doesn't stop people using 18S and you just label it as a 16S controller)

If I simulate at 16S and 18S and don't let any spikes go above 80V (Since there are 80v electrolytics and INA240 rated is 80v) I get 

(18S) 75v 200A 

(16S) 67.5V 550A​

Great work on the power stage layout, it is really nice and compact. I have been looking at something similar with HSOF8 fets, but they are so big the inductance is always too high. So I am also going to start using DirectFETs as well. Although to continue unofficial support for 18S I will use 100V fets and Electrolytics. Possibly switching to the Allegro hall sensors for current measurements, at which point a 150v version is possible.

Last seen: 5 hours 53 min ago
VESC Original
Joined: 2017-06-02 19:21
Posts: 79

Current sense and dc-dc converter options are such a headache above 80v if you're trying to keep it small and need to measure +/- 300A. There's a few buck converters up to about 140V, above that it's mostly flyback converters with 80V minimum voltage. There's isolated current shunt options but they need isolated dc-dc supplies and an opamp to let the stm32f4 ADC read them. You need to find space for 3x isolated dc-dc, 3x opamps and all the passives to go along.