ELECTRIC POWER STEERING DEVICE

摘要

Provided is an electric power steering device capable of performing, using a synchronous reluctance motor having nonlinear current-torque characteristics, a torque control by simple arithmetic processing. The electric power steering device transmits a target torque from an EPS controller (41) to a motor controller (51).  The motor controller (51) calculates a target current effective value (I) and a target current phase (?) from the input target torque.  Switching between whether the target current effective value (I) and the target current phase (?) to be calculated here is calculated so as to output the maximum torque (the maximum torque obtainable by the minimum current effective value) or the maximum output (the maximum output obtainable by the minimum current effective value) is performed using the output duty ratio of a PWM converter (57) comprising a 3-phase inverter.  Next, a 3-phase/2-axis converter (53) calculates a target q-axis current (Iq) and a target d-axis current (Id) from the target current effective value (I) and the target current phase (?).  The PWM converter (57) performs a duty control to perform the torque control of a motor (58).