Inducter wrote: ↑
Mar 03, 2018 3:07 am
What is the thinking behind so many motors and twice as many controllers? Is there any advantage in it? 6 motors and 12 controllers are a lot of opportunities and space for things to go wrong and cause unwelcome costs. Plus, they'll take up the space you may want for more batteries, more power.
The motors are to increase the inductance each controller sees. With a 90mm stator for the same kv the inductance will be 1.5x less. It’s the same reason for the multiple controllers, higher mutual inductance for the same kv.
Another thing the multiple controllers does is increase redundancy in case of failure. Each motor will be run as 2 sets of 3 phase windings separates by 30 degrees. Basically if one controller or winding fails, the motor still works and only has a slight reduction in Km. It also reduces torque ripple.
On top of all of those things, with multiple controllers for each motor, each controller will have a simpler, cheaper powerstage. Less worry for current sharing between parallel FETs. It will also make so the power stages are relevant to this community as a high power ebike or small motorcycle controller.