Load torque estimation method and torque control device

摘要

PROBLEM TO BE SOLVED: To provide a method for estimating load torque and the structure of a torque controller realizing highly accurate torque control at low cost. SOLUTION: Product of the rated value Ran of armature resistance and the derivative dIa/dt of armature current Ia is subtracted from the derivative dE/dt of input voltage and the difference is multiplied by the rated value Jn of inertial moment of armature. On the other hand, it is divided by the rated value Ken of induction voltage constant of a motor and the quotient is subtracted from the product of the armature current Ia and the rated value Ktn of torque constant of the motor to determine an estimated value of load torque TLh. The structure of a controller utilizing this method comprises a decision section 3 delivering a stop signal of a motor 1 when the estimated value of load torque TLh exceeds a target torque value Tc, or a motor r.p.m. decision section delivering a stop signal of the motor 1 by comparing a value obtained by subtracting a total r.p.m. N from a target r.p.m. Nc with a stationary r.p.m. Sn.