You are here

4.2 hw Erpm bldc mode

3 posts / 0 new
Last post
Katt
Offline
Last seen: 1 year 4 months ago
Joined: 2020-12-02 14:55
Posts: 5
4.2 hw Erpm bldc mode

 

I change the subject hoping in some response. Thank you

-------------

Hello to all,

sorry for the hassle and thanks to anyone who wants to help me. in this forum I looked for information about ERPM max in hardware 4.20 (flipsky) but i can't undestand well what is the real limit of esc....firmware latency, fet driver limit or mosfet limit? I think that limit is the max pwm frequency that stress power circuitry because as the frequency increases switching losses also rise. This is my personal opinion but if someone could tell me i will be happy. All this story because I have to do this setup: 12S lipo pack with a 4.2vesc and a 1100KV 4 poles inrunner motor (2 pole pair). The max Erpm should be 1100kv*50v*2pole pair= 110000   I don't use FOC but i go in BLDC mode.. Probably all burn.. Could someone help me?

Thank you.

Katt

TheFallen
Offline
Last seen: 5 months 3 weeks ago
VESC Original
Joined: 2017-09-11 11:46
Posts: 222

tbh this is a quiet forum, and honestly without pictures & settings it's hard to debug other peoples problems.

Max ERPM varies due to a number of factors based on firmware and hardware. But IIRC v4.12 hardware VESCs with <v3 firmware are usually limited to around 60,000ERPM. Newer VESCs firmware/hardware raises this to 120,000ERPM. Sure switching losses are a problem at higher frequencies but tbh, the PWM frequency is above the eRPM anyway so that doesn't matter so much. It's usually the microcontroller's cycle time, how long it takes the microncotroller at the heart of the VESC to do the maths for each cycle.
 

Katt
Offline
Last seen: 1 year 4 months ago
Joined: 2020-12-02 14:55
Posts: 5

Thank you TheFallen. in this moment I haven't assembled everything yet, mine was a technical curiosity.

 

I am about to try the configuration in first post and i was wondering what could be the reasons for rpm limit. 

The strange thing is that some hw reach 150Kerpm others do not but use the same fw core, if the cycle time calculation is not sufficient why some hardware reach more rpm (in my case bldc configuration need less math than foc)? Maybe i am wrong because i don't know how firmware works on various devices. However soon i'll try the setup and hope go well.