Torque sensor is a core component of automotive electric power steering（ EPS） system

a new kind of torque sensor based on electromagnetic induction principle is proposed. Structure and working principle of the sensor are introduced. Calculation formula of magnetic field and mathematic model for output voltage are deduced with the theory of electromagnetic field. Electromagnetic induction system of sensor is modeled and simulated by using Ansoft Maxwell. The simulation result reveal that the magnetic field of circumferential air-gap similar to square wave and the output voltage signal is similar to sine curve

the simulation result of magnetic field distribution and the output voltage are consistent with the theoretical calculation.