I am studying how electric motors work. In doing so, I came across multiple contradictory information on the torque curve of electric motors. For hobby-sized motors DC motors, the torque curve tends to be linear (e.g. [D.C. Motor Torque/Speed Curve Tutorial:::Understanding Motor Characteristics (mit.edu)](http://lancet.mit.edu/motors/motors3.html) ). AC motors on the other hand have different torque characteristics (e.g. [main-qimg-a7895103f0f37d89e82e18b928786d64-lq (602×395) (quoracdn.net)](https://qph.cf2.quoracdn.net/main-qimg-a7895103f0f37d89e82e18b928786d64-lq)).
My problem has to do with electric vehicles; they have both a constant torque region and a constant power region, and it resembles nothing like the above two types of motors, despite both being used in Teslas and other BEVs. I couldn’t find much information about why that is the case, but my research points toward some form of voltage / current control to shape the torque curve. Please ELI5, thanks.