ajdelange
Well-known member
- First Name
- A. J.
- Joined
- Dec 8, 2019
- Threads
- 4
- Messages
- 3,203
- Reaction score
- 3,409
- Location
- Virginia/Quebec
- Vehicles
- Tesla X LR+, Lexus SUV, Toyota SR5, Toyota Landcruiser
- Occupation
- EE (Retired)
At the root of vector space control is knowing where the magnetic field of the rotor is relative to that of the stator. If a wheel breaks loose the rotor is going to get ahead of the stator field and the controller will immediately advance the phase of the stator to maintain lock. As the free wheel needs no torque the angle will be small and little torque produced meaning the power to that motor is immediately (and automatically) reduced. Thus control is through torque management, at least in the inner most loops of the control system. Obviously the outer loops are concerned with speed as that is what the driver ultimately controls.
The reason is, in a nutshell, that they have electric motors which inherently have broad torque vs speed characteristics meaning that high torque is available at any speed.
The car is designed to do 0 - 60 in a certain length of time and the torque limitations are determined by that. You can always get more torque by running more current but torque stresses mechanical parts. The 0 - 60 run is at the systems torque limit. The controllers are set to limit current and angle to that which keeps torque production in the safe region. You can't ever get more torque than that. Now you can get that much torque whenever you are in the torque limited region. IOW if you want to leave every stop sign as if you are doing a 0 - 60 determination run you are free to do so and given that this is quite an experience, at least at first, many do. The result is that many Tesla owners find their tyres wearing faster than they expect (torque translates to thrust though slip). Keep that in mind next time you are tempted.
The reason is, in a nutshell, that they have electric motors which inherently have broad torque vs speed characteristics meaning that high torque is available at any speed.
The car is designed to do 0 - 60 in a certain length of time and the torque limitations are determined by that. You can always get more torque by running more current but torque stresses mechanical parts. The 0 - 60 run is at the systems torque limit. The controllers are set to limit current and angle to that which keeps torque production in the safe region. You can't ever get more torque than that. Now you can get that much torque whenever you are in the torque limited region. IOW if you want to leave every stop sign as if you are doing a 0 - 60 determination run you are free to do so and given that this is quite an experience, at least at first, many do. The result is that many Tesla owners find their tyres wearing faster than they expect (torque translates to thrust though slip). Keep that in mind next time you are tempted.
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