Robert Boschgmbh

Hans-Martin Heinkel

Gerhard Knecht

Rainer Josef Berger

An electronically commutable motor, whose excitation windings can be fed with current via semiconductor output stages from an electronic control unit using pulse-width modulated control signals and, in this context, which generate a rotating field in the stator of the motor, the rotating field placing the permanent magnet of the motor in rotational motion. Without position sensors, a reliable start-up in the rotational direction is achieved even given a high mass moment of inertia, a small cogging inertia, and poor damping such that, during the start-up of the motor, the control unit, during a specific or specifiable start-up phase, drives the semiconductor output stages in overlapping control phases using PWM control signals, whose pulse-width ratio rises from a minimum to a maximum and then falls again to the minimum, that the overlapping areas of the control phases in the affected excitation windings generate currents which yield a virtually continuous torque curve, and that, in the start-up phase, by shortening the commutation time between the control phases, coming after one another, the commutation frequency and thus the rotational speed of the motor is increased.

Electronically commutatable motor

A method for controlling a servo system (10) having friction, in which the non-linear characteristic (20) of the position controller (12) is defined such that the magnitude of the variable Ns, Vs supplied to the servo system (10) having friction in the case of a control deviation .DELTA.x lying outside a predeterminable target region (21) produces a torque or a force which is adequate to tear the servo system free of the stiction torque or stiction and such that the movement energy of the servo system (10) can be dissipated in the target region (21). The additional use of an integral component, which is preferably a function of the control deviation .DELTA.x, increases the steady state accuracy.

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Stuttgart, Germany

Hans-Martin Heinkel