Abstract: A control method for a sensor-less, brushless, three-phase DC motor. The stator coil in the electromagnets inside the motor may be used as the inductive element through which a voltage regulator can regulate the current as a means of regulating the output voltage. The value of the control signal provided to the drivers controlling power to the coils may be calculated based on at least the rail voltage, as measured in real time. This allows for a wide variation of input voltages, while maintaining a relatively constant output power to the motor. In general, by taking into account the value of the rail voltage when determining the final value of the control signal that is applied to the stator coils, the maximum current through the stator coils may be scaled to the same magnitude current that would be expected to flow through the coils if the rail voltage were the rated (nominal) fan/motor voltage, even when the actual rail voltage is different, e.g. higher than the rated fan/motor voltage.

Abstract: A control method for a sensor-less, brushless, three-phase DC motor. A pulse-width modulation (PWM) duty cycle may be calculated. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error (ZCE). The current value of an integral term corresponding to a rotational period may be updated according to the sign of the ZCE. The integral term may be updated periodically and multiple times during each rotational period. The ZCE may be subtracted from the integral term, and the resulting value may be used to generate one or more time values.

Abstract: A control method for a brushless, three-phase DC motor. The motor may include a plurality of electromagnets and a rotor. A voltage induced by rotation of a rotor may be sampled at an expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values, may be calculated. A delta zero crossing error may be calculated. The delta zero crossing error may be calculated based on a difference between the first sampled voltage value and the calculated average. The plurality of electromagnets may be commutated. Commutation timing for the plurality of electromagnets may be determined based at least in part on the delta zero crossing error.

Abstract: System and method for aligning and initiating rotation of a rotor in a motor. The motor may include the rotor and a plurality of pairs of electromagnets. The energy needed for alignment of the rotor of the motor may be used to generate the first movement in forced commutation. The energy needed for alignment may be combined with the initial energy to start the motor. The logic may be configured to align the rotor of the motor by energizing the three coils of the motor. Pulse width modulation may be applied to the first coil to control current on the coils; when a maximum PWM duty cycle is reached, the coil not required to rotate the correct direction may be released, thereby initiating motion in a rotor of the three phase motor. A rotation period may be determined. One or more pairs of electromagnets of the plurality of pairs of electromagnets may be excited at a first excitation level. The excitation level may be increased, over a second period of time, to a second excitation level.

Abstract: A control method for a sensor-less, brushless, three-phase DC motor. A pulse-width modulation (PWM) duty cycle may be calculated. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error. The delta zero crossing error may be multiplied by a first constant representing electromechanical properties of the motor to produce a representation of an angular velocity. One or more time values may be generated based on the representation of the angular velocity. Operation of the motor may be controlled based on the one or more time values and the PWM duty cycle.

Abstract: System and method for digitizing analog voltage signals. A first voltage signal may be received at a comparator. A ramp signal may be received at the comparator. The ramp signal may be generated by a ramp generator. An output signal may be generated by the comparator. The output signal may indicate whether the analog voltage signal or the ramp signal is greater. The output signal may be conveyed to logic circuitry by the comparator. Control information may be conveyed by the logic circuitry to the ramp generator. The ramp generator may generate the ramp signal based on the control information. The logic circuitry may determine a digital representation of the first voltage signal based on the output signal from the comparator and the control information.

Abstract: System and method for initiating rotation of a rotor in a motor. The motor may include the rotor and a plurality of pairs of electromagnets. A rotation period may be determined. One or more pairs of electromagnets of the plurality of pairs of electromagnets may be excited at a first excitation level. The excited one or more pairs of electromagnets may be determined based on the rotation period. The excitation level may be decreased, over a first period of time, to a second excitation level. The second excitation level may be a lower excitation level than the first excitation level. The excitation level may be increased, over a second period of time, to a third excitation level. The third excitation level may be a higher excitation level than the second excitation level. The rotation period may be decreased over the first and second periods of time.

Abstract: A control method for a brushless, three-phase DC motor. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error. A pulse-width modulation duty cycle may be adjusted based on the delta zero crossing error. The pulse-width modulation duty cycle may be used to control a rotational velocity of the rotor.

Abstract: A system and method are presented for aligning a rotor in a motor. The motor may include the rotor and a plurality of pairs of electromagnets. One or more pairs of electromagnets may be excited at a first excitation level. The one or more pairs of electromagnets may be less than all of the plurality of pairs of electromagnets. The excitation of the one or more pairs of electromagnets may be increased to a second excitation level over a first period of time. The excitation of the one or more pairs of electromagnets may be decreased to a third excitation level over a second period of time. Exciting the one or more pairs of electromagnets, increasing the excitation, and decreasing the excitation may cause the rotor to stop in a known position.

Abstract: A control method for a sensor-less, brushless, three-phase DC motor. The effects of commutation on the motor may be minimized using a sinusoidal current drive on each electromagnet. The “off” times and/or the “on” times of the drive transistors controlling the electromagnets in a full “H-bridge” configuration drive scheme may be delayed. By overlapping the drive signals to the electromagnets with respect to a commutation command, the effects of switching between electromagnets may be minimized. In addition, the “on” and “off” times may also be adjusted during the overlapping to further ensure that the coils continuously conduct current, and that the current does not change direction during the switching. The delays, and hence the overlap times of the coil drive signals may be dynamically controlled, for example by using digital timers, making the response predictable and easily controlled.

Abstract: A control circuit for controlling the rotational speed of a fan may include a memory element to store operating data corresponding to an operational profile of the fan defined by RPM (revolutions per minute) versus temperature, with the operating data comprising a respective temperature value and a respective RPM value for each respective operating point representing a change in slope of a function that corresponds to the operational profile of the fan. A processing unit may operate to receive a present temperature value, retrieve the operating data from the storage unit, and identify a pair of consecutive operating points such that the present temperature value is greater than a lower respective temperature value of the pair of consecutive operating points, and lower than a higher respective temperature value of the pair of consecutive operating points.

Abstract: A control method for a sensor-less, brushless, three-phase DC motor. A pulse-width modulation (PWM) duty cycle may be calculated. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error. The delta zero crossing error may be multiplied by a first constant representing electromechanical properties of the motor to produce a representation of an angular velocity. One or more time values may be generated based on the representation of the angular velocity. Operation of the motor may be controlled based on the one or more time values and the PWM duty cycle.

Abstract: A system (S) for combining multi-spectral images of a scene includes a first detector (18) for transmitting a scene image in a first spectral band. A separate, second detector (22) senses the scene in a second spectral band. The second detector (22) has an image output that is representative of the scene. A transparent display (26) mounted in the output viewing path (30) of the first detector (18) and displays a displayed image in the second spectral band. The image of the transparent display is aligned such that the image (12) of the scene in the second spectral band combines with the image output (10) in the first spectral band. The combined multi-spectral images (54) are conveyed to an output (32) for a user (U).

Abstract: A charging/discharging apparatus uses constant charging current and constant discharging current to reduce the possibility of building memory in the cells of a battery. Memory reduces battery capacity and eventual failure will result since the cells will refuse to take any charge. A charger circuit includes a current source receiving supply voltage to couple constant charging current to the battery and an amplifier is coupled to receive reference voltage from a source and feedback voltage from the battery to connect supply voltage to the current source when the reference voltage is greater than the feedback voltage. A discharger circuit utilizes a current sink receiving supply voltage to couple constant discharging current to the battery. An amplifier receives reference voltage from a source and feedback voltage from the battery to connect supply voltage to the current sink when the reference voltage is less than the feedback voltage.

Abstract: The disclosed invention is a generic Drone Control System or alternatively method to remotely pilot an air vehicle. The present invention essentially comprises a converted aircraft or other air vehicle and a ground station from where the drone is remotely controlled. Also disclosed as part of the Drone Control System are a plurality of means to transfer information and data between the ground station and the drone.