Trinamic Motion Control Gmbh & Co. Kg

Maxim Integrated Products, Inc.

Bernhard Dwersteg

Lars Larsson

Stephan Kubisch

Described is a method and a circuit arrangement for controlling a stepper motor in a voltage-controlled or voltage-regulated operating mode, having a bridge circuit provided for a motor coil (A) with semiconductor switches (HS, HS, LS, LS) for applying a first and a second PWM voltage (U(LA), U(LA)) having opposite polarity to the motor coil (A) and having a charge pump for switching at least the high-side semiconductor switch (HS, HS) of the bridge circuit. Because the charge pump must wait for a blocking or dead time before a further semiconductor switch can be switched after switching a first semiconductor switch, the time interval between a rising edge of one of the two PWM voltages and a subsequent rising edge of the respective other PWM voltage is increased at least until the blocking or dead time of the charge pump has elapsed.

Method and circuit arrangement for controlling a stepper motor

A method and a circuit assembly are described with which, in a stepper motor, a mechanical load applied to the motor shaft of which can be detected without a sensor in a voltage-based operating mode in which a nominal coil current is generated by applying a predetermined coil voltage (Us) to the coil. The coil is connected in a bridge branch of a bridge circuit formed from a first to fourth semiconductor switch (S, . . . S), wherein the predetermined coil voltage (Us) is applied to the coil with a variable duty cycle (T) by switching the semiconductor switch in the form of at least one PWM voltage (U(A), U(A)). The motor load is detected in the form of a load indicator signal (L) which represents a phase shift between a zero crossing of the predefined coil voltage (Us) and the next zero crossing of the coil current (Icoil) generated thereby, wherein a zero crossing of the coil current (Icoil) is defined when, in those time intervals (tm) in which the PWM voltage (U(A), U(A)) applied to the coil is zero, a polarity change occurs in a voltage dropping across the internal resistances of the semiconductor switches due to the coil current.

Method and circuit assembly for sensorless load detection in stepper motors

A method and a circuit arrangement for damping stepper motor resonances during operation of a stepper motor (M), in particular in the medium und high speed range, is described, wherein the coils (A; B) of the stepper motor (M) are each connected into a bridge circuit (Br; Br) comprising semiconductor switches (Sw, . . . Sw), in order to impress into the coils (A; B) a predetermined target coil current (I; I). The resonance damping is essentially achieved by activating a passive FD-phase in the zero crossing of the target coil current (I; I), during which all 10 semiconductor switches (Sw, . . . Sw) are opened or switched blocking, in order to thereby feed a coil current flowing in the related motor coil (A; B) back into the supply voltage source either via inverse or body diodes and/or via diodes (D, . . . D) connected in parallel to the semiconductor switches (Sw, . . . Sw) in the reverse direction between the positive supply voltage (+V) and ground potential.

Method and circuit assembly for the resonance damping of stepper motors

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.

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.

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.

Method and circuit assembly for driving a stepper motor

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.

Method and circuit arrangement for detecting motor load without sensors and for controlling motor current according to load for a stepper motor

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.

Method and circuit arrangement for controlling current in motors

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.

Method and circuit assembly for current control in 3-phase motors

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.

Method and circuit arrangement for sensorless engine load detection and for controlling the motor current in accordance with the load value in stepper motors

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.

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Hamburg, Germany

Bernhard Dwersteg