Electromagnetic switch control device

Abstract

Provided is an electromagnetic switch control device capable of stabilizing a contact pressure by predicting a near-future value of an operation coil current and performing control such that the near-future value does not fall below a holding current threshold value by a control unit. An electromagnetic switch control device 1 opens and closes 13 by an electromagnetic force corresponding to energization of operation coils 16 and 17, and includes PWM control units 21 to 23 that perform PWM pulse width modulation control of a current value A flowing through the operation coils 16 and 17. The PWM control units 21 to 23 estimate the near-future predicted current value flowing through the operation coils 16 and 17 by using a terminal voltage V of the operation coils 16 and 17, and perform PWM control based on the estimated current value. The predicted current value Y is estimated by using an impedance Z of the operation coils 16 and 17. The impedance is a variable obtained by current values A1 and A2 and terminal voltages V1 and V2 of the operation coils 16 and 17, and a constant approximated over a predetermined period from a latest past to a present time is used. The impedance is updated for each predetermined period.

Dependencies are inferred from the claim text.