Abstract: A method and a circuit arrangement for damping stepper motor resonances during operation of a stepper motor, in particular in the medium and high speed range, is described, wherein the coils of the stepper motor are each connected into a bridge circuit comprising semiconductor switches, in order to impress into the coils a predetermined target coil current. The resonance damping is achieved by activating a passive FD-phase in the zero crossing of the target coil current, during which all semiconductor switches are opened or switched blocking, in order to thereby feed a coil current flowing in the related motor coil back into the supply voltage source either via inverse or body diodes and/or via diodes connected in parallel to the semiconductor switches in the reverse direction between the positive supply voltage and ground potential.

Abstract: A method and a circuit arrangement is described by means of which a stepper motor can be operated by an adaptive control over a large rotational speed range, including a standstill, in which the motor is electrically fixed in a specific rotational position, and with high precision and running smoothness corresponding to a specified motor current course. This is achieved essentially by the fact that the motor is operated in a low rotational speed range including a standstill with a voltage-controlled or voltage-regulated first operating mode and in a higher or high rotational speed range with a current-controlled second operating mode.

Abstract: A method and a circuit arrangement is described by means of which a stepper motor can be operated by an adaptive control over a large rotational speed range, including a standstill, in which the motor is electrically fixed in a specific rotational position, and with high precision and running smoothness corresponding to a specified motor current course. This is achieved essentially by the fact that the motor is operated in a low rotational speed range including a standstill with a voltage-controlled or voltage-regulated first operating mode and in a higher or high rotational speed range with a current-controlled second operating mode.

Abstract: A method and a circuit assembly for driving a 2-, 3- or more phase stepper motor by predetermined courses of current curves, especially for a microstep operation, is disclosed. For minimizing the memory capacity needed for storing supporting points of the course of the current curve by which the microsteps are realized, the course of the current curve is divided into a number of segments to which each a basic or main gradient between adjacent supporting points is assigned, so that for each of the supporting points only a deviation of the gradient at this supporting point from the related basic or main gradient has to be stored.

Abstract: A method and a circuit arrangement are provided in which a mechanical load applied to the motor shaft or a load angle of the motor can be detected without sensors in a stepper motor. This is achieved substantially based on the fact that the load or the load angle creates a mutually induced voltage (back EMF) in the motor coils and the load or the load angle is detected by determining the phase shift of the motor voltage at at least one of the motor coil relative to the coil current at said motor coil connection, the phase shift being caused by the mutually induced voltage. A method and a circuit arrangement are also provided wherein the motor current of a stepper motor can be controlled according to load angle in such a way that the current consumption of the motor is relatively low.

Abstract: A method and circuit arrangement for controlling the motor current in an electric motor, in particular a stepper motor, by a chopper method is provided. In the method/circuit arrangement, the motor is operated with a coil current that follows a target coil current substantially more accurately at least at the zero crossing of the coil current. The method/circuit arrangement provides a good symmetry of the sinusoidal wave shape of the coil current with respect to the zero crossing of the coil current. The method is achieved in particular by the active control of the coil current both in the direction of a predefined target coil current and opposite the direction of the predefined target coil current with respect to upper or lower desired current values and a lowering or increasing of the upper or lower desired current values.

Abstract: A method and a circuit assembly for driving a 2, 3- or more phase stepper motor by predetermined courses of current curves, especially for a microstep operation, is disclosed. For minimizing the memory capacity needed for storing supporting points of the course of the current curve by which the microsteps are realized, the course of the current curve is divided into a number of segments to which each a basic or main gradient between adjacent supporting points is assigned, so that for each of the supporting points only a deviation of the gradient at this supporting point from the related basic or main gradient has to be stored.

Abstract: A method and circuit assembly are provided for controlling the motor current in an electric 3-phase motor, in particular in a 3-phase stepper motor, by a chopper process. For at least two of the three motor connections a respective chopper phase is cyclically activated, while a target motor current supplied for the motor connection in question is injected into the motor connection by a chopper process, while the two other motor connections are connected to each other.

Abstract: A method and a circuit arrangement are provided which enable a mechanical load applied to the motor shaft of a stepper motor (M) or a load angle of the stepper motor to be detected in a sensorless manner. A method and circuit arrangement are also provided which enable the motor current(s) of a stepper motor to be controlled in accordance with the load value such that the load angle is as high as possible without risking step losses, in order to maintain the current consumption of the motor as low as possible. This is achieved according by evaluating the temporal duration of the ON- and the FD-phases during the chopper control of the motor.

Abstract: A method and circuit assembly are provided for controlling the motor current in an electric 3-phase motor, in particular in a 3-phase stepper motor, by a chopper process. For at least two of the three motor connections a respective chopper phase is cyclically activated, while a target motor current supplied for the motor connection in question is injected into the motor connection by a chopper process, while the two other motor connections are connected to each other.

Abstract: A method and circuit arrangement for controlling the motor current in an electric motor, in particular a stepper motor, by a chopper method is provided. In the method/circuit arrangement, the motor is operated with a coil current that follows a target coil current substantially more accurately at least at the zero crossing of the coil current. The method/circuit arrangement provides a good symmetry of the sinusoidal wave shape of the coil current with respect to the zero crossing of the coil current. The method is achieved in particular by the active control of the coil current both in the direction of a predefined target coil current and opposite the direction of the predefined target coil current with respect to upper or lower desired current values and a lowering or increasing of the upper or lower desired current values.

Abstract: A method and a circuit arrangement are provided which enable a mechanical load applied to the motor shaft of a stepper motor (M) or a load angle of the stepper motor to be detected in a sensorless manner. A method and circuit arrangement are also provided which enable the motor current(s) of a stepper motor to be controlled in accordance with the load value such that the load angle is as high as possible without risking step losses, in order to maintain the current consumption of the motor as low as possible. This is achieved according by evaluating the temporal duration of the ON- and the FD-phases during the chopper control of the motor.

Abstract: A method and a circuit are provided for the commutation of brushless direct-current motors (BLDC motors), without using sensors, and especially to a method and a circuit for producing rotor position signals, without using sensors, for the commutation of brushless direct-current motors. In the method and the circuit Hall sensor signals are emulated without sensors and rotor position signals free of disturbing pulses and with a correct phase position are generated from said signals. The rotor position signals can be used to carry out a reliable, sensor-free commutation.

Abstract: A method and a circuit are provided for the commutation of brushless direct-current motors (BLDC motors), without using sensors, and especially to a method and a circuit for producing rotor position signals, without using sensors, for the commutation of brushless direct-current motors. In the method and the circuit Hall sensor signals are emulated without sensors and rotor position signals free of disturbing pulses and with a correct phase position are generated from said signals. The rotor position signals can be used to carry out a reliable, sensor-free commutation.

Abstract: A method and a circuit arrangement for operating stepper motors or other appropriately dimensioned synchronous motors is disclosed in which between a first operational mode for normal motor operation and a second operational mode for detecting an operating state of the motor like for example its load can be switched. The method and the circuit arrangement is especially provided for determining a reference position of the motor without sensors by driving the motor against a mechanical stop wherein an increase of the load which is caused by this, is detected as a change of the operating state (FIG. 1).