A drug delivery device including a reservoir configured to contain a fluid to be delivered by advancing a piston in the reservoir at an advancement speed defining a delivery rate for the medicament. The device further includes an electric motor configured to drive the delivery mechanism by rotation to advance the piston at the advancement speed. The device further includes a control unit that controls a rotational speed and an on state/off state of the electric motor. The control unit determines rotational speed of the electric motor based on a back-electromagnetic force signal provided from the electric motor while operating in a monitoring mode. The control unit controls the rotational speed of the electric motor such that a back-emf signal can be detected in the monitoring mode. The control unit modulates the on state/off state of the electric motor to adjust the delivery rate of the medicament.

A drug delivery device including a reservoir configured to contain a fluid to be delivered by advancing a piston in the reservoir at an advancement speed defining a delivery rate for the medicament. The device further includes an electric motor configured to drive the delivery mechanism by rotation to advance the piston at the advancement speed. The device further includes a control unit that controls a rotational speed and an on state/off state of the electric motor. The control unit determines rotational speed of the electric motor based on a back-electromagnetic force signal provided from the electric motor while operating in a monitoring mode. The control unit controls the rotational speed of the electric motor such that a back-emf signal can be detected in the monitoring mode. The control unit modulates the on state/off state of the electric motor to adjust the delivery rate of the medicament.

According to some embodiments, method for controlling a motor comprises generating a drive signal for the motor, the drive signal comprising a demand flux generating voltage parameter. A feedback torque generating current parameter and a feedback flux generating current parameter are determined based on a three-phase motor current measurement. A feedback flux generating voltage parameter is determined based on the feedback torque generating current parameter and the feedback flux generating current parameter. An estimated motor position and an estimated motor speed are determined based on the feedback flux generating voltage parameter and the demand flux generating voltage parameter. The drive signal is generated based on the estimated motor position and the estimated motor speed.

Examples described herein provide a method for overspeed protection of a motor of a gate crossing mechanism. The method includes monitoring, by an overspeed protection circuit, a voltage across a first Zener diode and a second Zener diode. An anode of the first Zener diode is connected to an anode of the second Zener diode. The method further includes, responsive to determining that a Zener voltage threshold is exceeded, allowing a current to flow into a gate pin of a triac. The triac controls the motor of the gate crossing mechanism.

A method of determining angular position (θ) of a rotor of an N-phase permanent magnet motor (PMM). A processor having an associated stored angular position determination (APD) algorithm is programmed to implement the algorithm to cause an associated motor controller to execute steps including forcing one vector at a time a phase vector set of current or voltage vectors to stator terminals of windings for the N-phases a positive and negative magnitude vector, wherein the vector magnitude is sufficiently small to not move the rotor, and a time duration for the forcing current or voltage vectors is essentially constant. The resulting stator current or voltage levels are measured for each current or voltage vector. An N-dimension current vector or voltage vector is generated from superposition of the resulting stator current levels or resulting stator voltage levels. The N-dimension current vector or voltage vector is used to determine angular position.

A method of determining angular position (θ) of a rotor of an N-phase permanent magnet motor (PMM). A processor having an associated stored angular position determination (APD) algorithm is programmed to implement the algorithm to cause an associated motor controller to execute steps including forcing one vector at a time a phase vector set of current or voltage vectors to stator terminals of windings for the N-phases a positive and negative magnitude vector, wherein the vector magnitude is sufficiently small to not move the rotor, and a time duration for the forcing current or voltage vectors is essentially constant. The resulting stator current or voltage levels are measured for each current or voltage vector. An N-dimension current vector or voltage vector is generated from superposition of the resulting stator current levels or resulting stator voltage levels. The N-dimension current vector or voltage vector is used to determine angular position.

A motor control device includes: a plurality of sensors detecting a rotation position of a rotor and outputting a position detection signal; a rotational speed determination part determining whether a rotational speed of a brushless motor is equal to or less than a predetermined threshold value based on the position detection signal; and a motor control part. An energization control part included in the motor control part uses, between a first mode and a second mode, different sensor signals serving as a trigger for an energization timing of each phase. In the first mode, an energization timing to a second phase is advanced relative to a timing at which the position detection signal of a first sensor turns on. In the second mode, an energization timing to the second phase is retarded relative to a timing at which the position detection signal of the first sensor turns on.

A motor control device includes: a plurality of sensors detecting a rotation position of a rotor and outputting a position detection signal; a rotational speed determination part determining whether a rotational speed of a brushless motor is equal to or less than a predetermined threshold value based on the position detection signal; and a motor control part. An energization control part included in the motor control part uses, between a first mode and a second mode, different sensor signals serving as a trigger for an energization timing of each phase. In the first mode, an energization timing to a second phase is advanced relative to a timing at which the position detection signal of a first sensor turns on. In the second mode, an energization timing to the second phase is retarded relative to a timing at which the position detection signal of the first sensor turns on.

An image forming apparatus includes a stacking portion, a pickup roller, a motor, an image forming unit, and a controller. Upon receiving an instruction for starting a first image forming job, the controller performs an initial operation of supplying current to a motor winding of the motor in a stop state and determining a phase of the rotor based on the flowing current. Based on the determined phase, the controller supplies current to rotate the rotor from its stop state and holds the rotor at a first phase when the first job ends. Upon receiving start instructions for a second image forming job within a period until a predetermined time elapses from when the rotor is held at the first phase, the controller rotates the rotor without performing the initial operation. The controller stops supplying current to the winding if no instructions are not received for starting the second job.

An image forming apparatus includes a stacking portion, a pickup roller, a motor, an image forming unit, and a controller. Upon receiving an instruction for starting a first image forming job, the controller performs an initial operation of supplying current to a motor winding of the motor in a stop state and determining a phase of the rotor based on the flowing current. Based on the determined phase, the controller supplies current to rotate the rotor from its stop state and holds the rotor at a first phase when the first job ends. Upon receiving start instructions for a second image forming job within a period until a predetermined time elapses from when the rotor is held at the first phase, the controller rotates the rotor without performing the initial operation. The controller stops supplying current to the winding if no instructions are not received for starting the second job.