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:
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. The second excitation level may be a higher excitation level than the first excitation level. The rotation period may be decreased over the first and second periods of time.
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 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. The present position of the rotor in the motor may be determined using Hall sensors configured in the motor, or it may be determined using the un-energized electromagnets in a motor without Hall sensors.
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 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:
An improved hydroponic nutrient delivery gardening system apparatus is described. This improved hydroponic delivery gardening system apparatus improves upon existing systems by minimizing the effects of sunlight and heat on the nutrient solution system without the use of an external nutrient cooling system, improve nutrient availability to roots, improve oxygen availability to roots, and improve the consistency of, and the ability to accurately measure, the pH of the media and nutrient mix.
Abstract:
A resistive sensing touch panel may include row receiver tracks and column drive tracks. A controller may send and receive control signals and sense signals, respectively, to and from the resistive touch panel. The resistive touch panel may provide sense signals when a touch of the panel is detected. The sense signals may be sampled on a number of rows. When sampling a given row, the controller may change the termination of that row by coupling the end of the sampled row to a resistor having a higher value then terminating resistors coupled to the end of non-sampled rows that are adjacent to the sampled row. The controller may further pull the terminating resistors coupled to the end of the non-sampled adjacent rows to a supply rail voltage while the sampled row is being sampled.
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 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. The processing unit may calculate a desired RPM value corresponding to the present temperature value by performing linear interpolation between the pair of consecutive operating points, and output the desired RPM value to a closed-loop fan controller configured to control a rotational speed of the fan according at least to the desired RPM value.