Sodeco-saia Ag

Mercedes-benz Aktiengesellschaft

Lgz Landis Gyr Zug Ag

Saia Ag

Sodeco-saida Ag

Pierre Boillat

Dieter Heinle

Wolfgang Straub

Juergen Blessing

A device for driving a positioning element via a stepping motor is described. This device makes it possible to continue operating the stepping motor in conjunction with its use as an encoder during phases without electrical control, so that the position last reached under electrical control, with a zero-current change in the position, possibly as a result of manual operation of the positioning element that is rotationally or frictionally coupled with the motor rotor, is constantly updated so that the control electronics is informed at all times of the actual position from which the stepping motor is to be controlled electrically to assume a new position. The device not only permits eliminating indexing devices that are subject to wear, but also allows automatic return, for example of a positioning element to its previous starting position after it has been shifted or adjusted from by an outside influence. The device is usable in conjunction with an operating or adjusting element in a vehicle and in this regard is especially advantageously usable in conjunction with an adjusting element that functions as a manual operating element of the heating or air conditioning system.

Device for driving a positioning element by means of a stepping motor

A driving device for controlling the driving frequency for a stepping motor includes a voltage control pulse generator for producing electrical pulses for driving the stepping motor. The pulse generator includes an RC network providing a time base for the pulse width and the operating frequency of the electrical pulses. The RC network includes at least one controllable resistance and a capacitor connected to control the controllable resistance by the charging and discharging of the capacitor.

Driving device for a stepping motor

A pulse-width modulator is used to control the sequence generator of a stepping motor to stabilize the stepping motor. One input to the pulse-width modulator is a cyclic sequence of pulses. The other input to the pulse-width modulator is an error-correction signal. The error-correction signal is proportional to variations about an average of the sum of the currents produced by the sequence generator. The error-correction signal is used by the pulse-width modulator to modulate the duration of individual pulses in the cycle sequence of pulses to produce a sequence of pulses of variable duration. The pulses of variable duration serve to control the sequence generator and stabilize the stepping motor.

Stabilizing arrangement for a stepping motor

In an apparatus and method for preventing instability of a stepper motor operated by a plurality of alternating currents of different respective phases and controlled by a sequence of control pulses, the control pulses defining an angular parameter of the stepper motor, the steps include determining the sum of the phase currents, transforming the sum of the phase currents into a voltage fluctuating about an average value, determining the average voltage, and thereafter feeding back the fluctuating voltage so as to angle-modulate said control pulses.

Restraining the instability of a stepper motor

Circuitry for measuring the torque of a stepping motor is disclosed. The circuitry is based on the fact that the decay time of the current flowing through the stator coils is a function of the torque of the stepping motor.

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Meyriez, Switzerland

Pierre Boillat