A valve actuator (10) has a damping circuitry including a capacitive damping circuit (37), which is activated in the event of generator operation of the stepper motor (18). The damping circuitry, together with the motor winding (26), forms a resonance assembly LCR, which has the effect of stabilising and regulating rotational speed. The rotational speed of the stepper motor (18), running in generator operation, is held constant within limits, specifically without the control intervention of control circuitry. Therefore, the damping circuitry can operate even in the currentless state of the control system and is reliable regardless of external current supply. Fast closing is achieved, and excessively long post-running of the motor (18) is reliably prevented.

A bipolar stepper motor driving device drives a stepper motor including stator coils having plural phases. The bipolar stepper motor driving device includes H-bridge circuits, a current detector, a control circuit, and a re-turning-on instruction unit. The H-bridge circuits are provided correspondingly to the phases of the respective stator coils. The current detector detects current flowing in the stator coils. The control circuit executes drive control of the H-bridge circuits. The re-turning-on instruction unit commands the control circuit to switch into a short-circuited state a stator coil which has shifted from an energized state to an off-state among the stator coils, on a condition that an absolute value of a reverse current detected by the current detector has changed from a value larger than a threshold current value to a value smaller than the threshold current value.

According to one embodiment, there is provided a motor control device including a detection circuit, a control circuit and a drive circuit. The detection circuit detects, in a direct current motor with a first coil and second coil, a first parameter related to an induced voltage generated in the first coil and a second parameter related to an induced voltage generated in the second coil. The control circuit changes, according to a difference between the first parameter and the second parameter, at least one of a first amplitude control value of a current of the first coil and a second amplitude control value of a current of the second coil. The drive circuit drives, according to the changed amplitude control value, the first coil and the second coil, respectively.

Various embodiments of the invention describe systems, devices and methods used to improve network topology connectivity by implementing throughput analysis between an access point and a plurality of extenders. This throughput analysis may include measurements such as interference and load values.

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 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.

There is provided an analog electronic timepiece including a stepping motor in which a rotor magnetized in two poles is rotationally driven in a stator connected to a driving coil, a drive circuit for applying a drive pulse to the driving coil, the drive pulse being a pulse for driving the rotor, and a control unit for controlling application of the drive pulse by the drive circuit, in which when an induced voltage induced in the driving coil by rotation of the rotor satisfies a predetermined condition related to the induced voltage, the control unit controls the drive circuit so that the drive pulse is applied to the driving coil before free vibration of the rotor is settled.

In order to suppress high-frequency noise in micro-step driving of a stepping motor, a motor control device (100) includes an H bridge circuit (20) and control means for driving a switching element of the H bridge circuit (20) with a PWM signal and for setting a charge mode, a fast attenuation mode, or a slow attenuation mode for a motor coil. In a range from an electrical angle where the reference current value starts descending to an electrical angle of +52, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and then to the slow attenuation mode. In a range exceeding +52 and to +90 degrees where the reference current value starts ascending, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and, if the motor current exceeds the reference current value, then the control means switches it to the fast attenuation mode and further to the slow attenuation mode.

In order to suppress high-frequency noise in micro-step driving of a stepping motor, a motor control device (100) includes an H bridge circuit (20) and control means for driving a switching element of the H bridge circuit (20) with a PWM signal and for setting a charge mode, a fast attenuation mode, or a slow attenuation mode for a motor coil. In a range from an electrical angle where the reference current value starts descending to an electrical angle of +52, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and then to the slow attenuation mode. In a range exceeding +52 and to +90 degrees where the reference current value starts ascending, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and, if the motor current exceeds the reference current value, then the control means switches it to the fast attenuation mode and further to the slow attenuation mode.

An automated luminaire and method are provided. The automated luminaire includes a stepper motor, a mechanism moved by the stepper motor, and a control system coupled to the stepper motor. The control system rotates the stepper motor, senses a current passing through a motor winding of the stepper motor, determines from a calculated characteristic of the sensed current that the mechanism has contacted an end stop, and in response, stores data relating to a current position of the stepper motor in a memory of the control system.