Honda F1 project leader Yusuke Hasegawa has outlined a number of reasons why Honda has been struggling so badly in the beginning of the 2017 Formula One season. He confirmed that lots of problems were not discovered while running on the dynamo meter.
So what are they doing for the return path?gruntguru wrote:No - it will be a three phase motor. 1 wire per phase - no neutral or earth.
In an engine phases ale balanced so there is no return current in neutral.djos wrote:So what are they doing for the return path?
Cheers for that, I only studied basic electronics and never looked at AC power in depth.piast9 wrote:In an engine phases ale balanced so there is no return current in neutral.djos wrote:So what are they doing for the return path?
https://en.wikipedia.org/wiki/Three-pha ... tric_power
IGBT's are often used, they are a mix of Mosfet drive and bipolar transistor power switch.Wazari wrote:The MGU motors are AC 3 phase. I'm pretty sure in harvesting mode the power goes through the 3 cables through a series of bipolar transistors and capacitors and converted to DC then to the batteries. The process reversed to power the motors. I suspect there is tremendous amount of heat generated during this AC to DC to AC conversion process and where many failures occur.
Actually it will be more like FET, SiC transistors (you can go up to 1.2kV) also the heat generation depends on what topology you chose/frequency and size of the power components. There are topologies which are quite effective but they need bigger or more components and more measurement/control but you can go up to 96% of efficiency maybe even more (98%) if you make the setup work only in narrow operating window (voltage range).Wazari wrote:...bipolar transistors and capacitors... ...I suspect there is tremendous amount of heat generated during this AC to DC to AC conversion process and where many failures occur.
Higher voltage require thicker insulation of the copper wires which means less density of the winding.Abarth wrote:Higher voltages result always in better over all efficiency. Higher current means always higher losses, being it induction losses, resistive losses, whatever. Higher voltages and constant cable cross-section results in less losses, and with a given loss reduced copper weight.
Limits are the semiconductor voltage threshold and insulation materials, but 700 V is not anything high.
MGU-K (120kW) at 690V means about 100A current...
At 400V AC, it's already 170A.
Big cable car motors (in Europe) run often on 690V AC (3 phase) instead of 400V AC, this results in 400V per phase towards "ground" and around 565V peak, i.e. the battery pack (DC) would be on a voltage of around 570 V DC.
I thought super capacitors were ten times the size of equivalent batts and although would solve charging cycle discharging problems, would create a packaging problem?Mr.G wrote:Doesn't they use super-capacitors instead of batteries.
I'm pretty sure they are using IGBT in F1 to switch the current.Mr.G wrote:
Actually it will be more like FET, SiC transistors (you can go up to 1.2kV) also the heat generation depends on what topology you chose/frequency and size of the power components. There are topologies which are quite effective but they need bigger or more components and more measurement/control but you can go up to 96% of efficiency maybe even more (98%) if you make the setup work only in narrow operating window (voltage range).
Abarth - IGBT are usable for high voltage but they are bit slow... I mean we use them but not always... In F1 I think they go for SiC as they are the best you can get right now...
