Abstract: An excitation circuit for a flux switching motor. The circuit includes a low-value film capacitor across the DC side of a bridge rectifier. A plurality of electronic switches are arranged in an H-bridge configuration for switching current flow through an armature winding of the motor in accordance with a PWM control scheme and single-pulse control scheme controlled by a microcontroller. A start-up diode is placed across the field winding of the motor and is electronically switched out of the circuit after a startup phase of the motor has completed. The circuit implements armature energy recirculation through the field winding during startup to promote more uniform and quicker startup of the motor. The use of a film capacitor improves the power factor of the circuit, helps to eliminate the introduction of harmonics into the AC voltage source, and helps in mitigating EMI. Reverse commutation is used to bring the motor to a quick stop when it is powered off.

Abstract: In a PWM-controlled motor driving device, a phase current is prevented from undergoing an abrupt transition at phase current switching points, thereby reducing vibrations and noise of the motor. A PWM control section produces two independent PWM control pulse signals P1 and P2. Two energized phases, which are determined by an energization switching section, are energized with PWM control in parallel according to the PWM control pulse signals P1 and P2. A comparison section compares a current detection signal DS, which indicates the level of the current flowing through a motor coil, with various torque command signals TQ1, TQ2 and TQ3, which are produced by a torque command signal generation section. A masking section masks comparison results CR1 and CR2 as necessary. Thus, an ON period of the PWM control pulse signal P1 and that of the PWM control pulse signal P2 are determined.

Abstract: A dual motor configuration 10 is provided for driving two fans for moving air to cool an engine. The dual motor configuration includes a primary brushless motor 18 constructed and arranged to be electronically controlled to drive a first fan 16 over a range of speeds. A secondary brush motor 24 is constructed and arranged to be electronically controlled to drive a second fan 22 over a range of speeds. The secondary brush motor includes an electronic switching device 26 associated therewith for receiving a pulse width modulated signal for controlling speed of the secondary brush motor. Thus, different combinations of speeds of the first and second motors can be selectively chosen to meet cooling requirements.

Abstract: The present invention discloses devices and methods for improved starting and stopping of rotary motors. A rotary electrical machine (3) is supplied with a voltage from a voltage supply (10). The magnitude of a phase current is measured. The measured current value (IM) and applied voltage (U) is compared with what is expected for a predetermined target slip (ST), by means of a relation between phase current, applied voltage and slip. The comparison gives a discrepancy value, which is used to create a regulation signal (?U) to the voltage supply (10). To start and stop the machine, the target slip is increased and decreased, respectively, in a predetermined manner. The means for regulation may be provided as a separate add-on unit to existing soft starter equipment.

Abstract: A method of operating a cooling fan in a cooling system for a vehicle includes determining a required speed of the cooling fan. First and second signals are provided to a motor controller operatively connected to a motor having a rotatable portion connected to the cooling fan. The first signal coarsely controls a rotational speed of the motor by adjusting a voltage level provided to the motor and the second signal finely controls the rotational speed of the motor by pulse width modulation so that the cooling fan rotates at the required speed.

Abstract: An operating procedure for the motor (1) of an electric powered tool. The operating idle speed of the motor (1) is set to a value using regulator electronics (4), and the operating speed is the same as a chosen operating speed (n1). The motor (1) runs on a pre-determined and higher idle speed (n2) for cooling purposes after a specific idle time (?T). while the motor (1) runs on the pre-determined operating idle speed (n1). The engine speed is immediately set to the operating speed (n1) once again, when the motor requires a moment of strain at a certain period of time (T3) to maintain simple and comfortable operating procedures.

Abstract: A computer system includes a first heat generating element in which a heat generation amount is changed, a second heat generating element, a fan configured to cool the first and second heat generating elements, a first temperature sensor configured to detect a temperature of the first heat generating element, a second temperature sensor configured to detect a temperature of the second heat generating element, and a controller configured to control a rotation speed of the cooling fan, based on the temperatures detected by the first and second temperature sensors.

Abstract: A complementary fan rotational speed control method and apparatus for simultaneously monitoring the rotation speeds of two or more fans includes a control unit to output pulse width modulation (PWM) control power supply to activate operation of a first fan and a second fan. The first and the second fan deliver rotation pulse signals to the control unit. When the control unit detects the rotation speed of either the first or second fan decreases, it actuates other fan to increase rotation speed and issues a warning signal to secure cooling effect and increase the service life of the fans.

Abstract: A system and method for increasing resolution of pulse width modulated (PWM) signal duty cycle calculations in a fan speed control system operating to control rotational speed of at least one fan. The method may comprise obtaining a temperature reading from a first temperature sensor in the fan speed control system during a first time period. The temperature reading has resolution of a first number of bits. A portion of the first number of bits is selected for calculating a PWM signal duty cycle with the resolution of the first number of bits in the temperature reading using only the portion of the first number of bits and zone parameters associated with the first temperature sensor. The PWM signal duty cycle may then be converted into a PWM signal that may be provided to the at least one fan.

Abstract: A rotational speed controller maintains a constant low speed during idling, a constant high speed when a load is applied and controls motor rotational speed in the range between low and high speed to ensure safe operation when used in an electrically powered tool. When the current detection signal output from a current detection circuit is lower than a first predetermined value (during idling), a rotational speed setting circuit outputs a rotational speed setting signal indicating a first rotational speed to drive the motor at a constant low speed. When the current detection signal exceeds a second predetermined value (when a load is applied), the rotational speed setting circuit outputs a rotational speed setting signal indicating the second rotational speed to drive the motor at a constant high speed.

Abstract: Asynchronous motors are controlled by way of two- or three-phase controllers that include at least two pair of thyristors connected in antiparallel and fired at certain intervals. According to the inventive method, a fundamental wave with the desired frequency is defined for the first phase and in the other phase a respective fundamental wave is defined that has the same frequency as that in the first phase, but phase-shifted by corresponding values. For every phase, firing intervals are marked that have the same polarity as the respective fundamental wave. Those intervals of the potential firing intervals are used for every phase at which there is a potential firing interval in one of the two other phases. These intervals are used as the actual firing intervals.

Abstract: An improved fan useful for ventilating applications in motor vehicles features a modular structure, which facilitates quick replacement of any components likely to fail. A first module (110) is intended for permanent installation on the part that is to be cooled. A second module (110) is configured for quick engagement to and disengagement from the first module. The second module preferably comprises a hub (22; 362), an internal stator (60; 332) mounted on the hub, and one or more struts (74; 344) connecting the hub to a cylindrical casing part (76; 336) which surrounds but is spaced from the outside of the fan wheel (46; 348). The struts form a lattice (112) which can be easily grasped for swapping out the second module when repair or replacement becomes necessary.

Abstract: Method and device for controlling the angular speed of an electromechanical drive train with little damping. The control of the speed of the load driven in rotation by an electromechanical drive train with little damping, possibly having transmission nonlinearities such as play, without measuring said speed, is accomplished by using an observer in conjunction with a robust CRONE-type non-integer order controller, the physical realization of which is achieved by an integer order controller obtained by approximation in the frequency domain. The device thus provides good damping for the system in the presence of resonance frequencies and excellent robustness, while still allowing a relatively simple adjustment.

Abstract: An apparatus and method for monitoring memory system performance and controlling an operating parameter is provided. A plurality of digital events indicative of memory system operations is detected, from which a subset of digital events to count is periodically selected, the subset being those digital events occurring during a sampling window time interval. Responsive to each digital event of the subset, a transistor is switched on to conduct current from a power supply to a capacitor. The transistor is biased by the capacitor to operate in a constant current region providing a substantially fixed amount of charge added to the capacitor responsive to each digital event of the subset. The operating parameter is controlled responsive to the charge accumulated in the capacitor, representative of the count of digital events in the subset. In one embodiment, the sampling window time interval is selected pseudo-randomly within a periodic base time interval.

Abstract: A motor actuator (52) of a climate control system (37) includes an specialized electric motor (62) with a motor housing enclosing an encoder ring (104) on a motor shaft (77) having a plurality of opposite encoder-segment sets with encoder brushes (96a-b) on the housing wiping the encoder ring and thereby forming an encoder circuit through opposite segments of the encoder-segment sets. The electric motor further includes power and encoder terminals (98a-b and 100a-b) positioned externally of the motor housing with at least one power terminal being electrically coupled to one of the power brushes and at least one encoder terminal being electrically coupled to one of the encoder brushes. A control head (58) of the system includes a continuity pulse counter (72) coupled to the at least one encoder terminal for creating pulses representative of impedance in the encoder circuit and, therefore, movement of the motor shaft and a damper (40) linked thereto.

Abstract: A ventilator having an abnormal operation indication device includes a power supply circuit, a central processing unit, a fan motor, and a load sensing circuit. Thus, the load sensing circuit detects the abnormal operation signals through the sensor, so that the abnormal operation indication lamp on the panel of the ventilator lights, so as to indicate that the part of the ventilator is disposed at an abnormal operation state and needs to be inspected and amended, thereby facilitating inspection and maintenance of the parts of the ventilator.

Abstract: In a motor rotation rate detecting circuit incorporating a conventional differentiating circuit, raising the upper limit of the differentiating operation frequency of the differentiating circuit to cope with an increased range of the motor rotation rate causes the differentiating circuit to amplify high-frequency noise when the motor is rotating at a low rate. To solve this problem, a motor rotation rate detecting circuit embodying the invention incorporates a differentiating circuit that produces a rotation rate detection signal by differentiating a plurality of alternating signals having different phases that are output according to the rotation position of the motor, and the frequency response of the differentiating operation of the differentiating circuit is switchable according to the voltage of the rotation rate detection signal.

Abstract: A method of controlling an electronically commutated DC motor having a multiphase stator winding which has an even number m of winding phases which are each connected in series with a controllable semiconductor switch, parallel to one another, in which in a lower power output range of the DC motor the semiconductor switches are cycled using a pulse control factor which is predefinable as a function of the rpm within the consecutive periods when the individual winding phases are energized. To reduce the maximum power losses in the semiconductor switches, a setpoint pulse control factor required for a setpoint rpm is achieved within a selected setting range of the pulse control factor by alternatingly setting a comparatively greater pulse control factor and a comparatively lower pulse control factor, and the setting of the two pulse control factors is varied over time so that a voltage setting the setpoint rpm is set across the stator winding on the average over time.

Abstract: A thermal control variable-speed circuit without switching noise is connected with a driving circuit, which controls the rotation speed of a fan motor using a driving voltage. The thermal control variable-speed circuit includes a reference voltage output circuit and a driving voltage control circuit. The reference voltage output circuit outputs a corresponding reference voltage signal according to ambient temperature changes. The reference voltage output circuit has one end connected to a first resistor in series and to a second resistor in parallel. The driving voltage control circuit outputs a corresponding driving voltage according to the magnitude of the reference voltage signal.

Abstract: A multiphase motor has a plurality of ferromagnetically isolated stator electromagnets distributed about an axis of rotation. Successive ranges of speed during which the motor can be expected to operate are defined. A specific subset of the electromagnets is associated for each speed range, each specific subset comprising a different combination of electromagnets. Respective voltage magnitudes to be applied to each phase winding for each defined speed range are predefined. The motor speed is sensed throughout motor operation. In each defined speed range, only the electromagnets of the associated subset are energized, each of the energized electromagnets having applied thereto a different predefined voltage magnitude.

Abstract: A control system for an electric motor having a stator and rotor including an inverter for providing power to the electric motor, a controller for controlling the inverter, a low speed control block to estimate the rotor angular position using stator current components operating in the controller, a high speed control block to estimate the rotor angular position using stator current components and stator flux position operating in the controller, a transition switch in the controller to vary operation between the low speed control block and the high speed control block, and where the inverter is controlled by six step operation.

Abstract: Rotational force of a driving motor is transferred to a photosensitive drum via a planetary-rolle reduction device, so that the photosensitive drum is rotated. A speed detector set on the shaft of the photosensitive drum detects the rotational speed of the photosensitive drum. In accordance with the detected rotational speed of the photosensitive drum, the rotational speed of the driving motor is adjusted so that the photosensitive drum is rotated at a constant speed.

Abstract: A localized system for dissipating heat generated by an electronic component includes a controllable cooling element and a control system for controlling the cooling element. The control system adjusts a speed of operation of the cooling element in response to variations in power consumption of the electronic component.

Abstract: The invention concerns a method for regulating the rotation speed, of a motor with which a digital rotation speed controller is associated and which, during operation, furnishes an actual-value signal for the rotation speed in the form of a rotation speed frequency signal, toward a target rotation speed setpoint defined in the form of a setpoint frequency signal, having the following steps: in a first time segment, a first numerical frequency value that characterizes the rotation speed of the motor is ascertained from the rotation speed frequency signal; in a second time segment that is substantially simultaneous with the first time segment, a second numerical frequency value that characterizes the frequency of the setpoint frequency signal is ascertained from the setpoint frequency signal; by means of the first and second numerical frequency values, the rotation speed of the motor is regulated in the digital rotation speed controller to a rotation speed that is associated with the setpoint frequency signal a

Abstract: A method and apparatus for compensating for the asymmetrical phases of a spindle motor in a disc drive are provided. With the apparatus and method, compensation values are learned by sampling speed data during a period of operation of the disc drive where the speed is stable and only one control operation is performed per revolution of the disc. The sampled speed data is used to generate the compensation values for each of the phases of the spindle motor. The compensation values are stored in a compensation mechanism which is used by the spindle motor speed controller to provide compensation for the asymmetrical phases of the spindle motor. During Normal operation, the actual speed output of the spindle motor is measured and is subtracted from a reference speed to generate a difference speed value. Based on the corresponding electrical phase, the correct compensation value is fetched and is subtracted from the difference speed value to obtain a compensated difference speed value.

Abstract: The stop positions of start and end points for a slider are set by positionally adjusting a stopper and/or a stopper. The distance that the slider has traveled is learned according to a command from a control console in response to a manipulation of a learning manipulation element, and at least one of a speed and an acceleration is set by a speed regulator and an acceleration regulator. The control console outputs a drive signal to a motor based on at least one of the set speed in constant-speed movement of the slider and the set acceleration of accelerated movement of the slider and the learned distance that the slider has traveled, thereby moving the slider. For moving the slider to the start point or the end point, the control console controls the slider to move at a speed lower than the speed in constant-speed movement, and positions the slider at the start point or the end point.

Abstract: A wireless system uses a direct UHF radio frequency (RF) signal to control electric trains and train accessories. A controller, such as a handheld unit used by the toy train operator, accepts control commands and transmits encoded control data over a high frequency radio link directly to a receiver, on the toy train or train accessory, which decodes the commands and controls the toy train or toy train accessory functions with either unidirectional or bi-directional communication between the controller and the model train or train accessory. One controller has the ability to control many trains and other model train layout components such as signals and track switches even while other train operators are operating their trains on the same electric train track layout.

Abstract: Load fluctuation of a refrigerating cycle under severe conditions needs to be overcome. For instance, a compressor driver which can positively drive the compressor employed even in a vehicle is desirable. To be more specific, at the start of the compressor, a phase of the current flowing in the motor is controlled to be ahead of an induction voltage, then the advancement of the phase is controlled to decrease. Under an unstable condition to detect a position, such as at the start under pressure-difference, the foregoing control allows the phase to advance up to the current-phase where the max. torque can be produced, thereby drawing the instantaneous max. torque of the motor for starting the compressor. Then the control reduces the advancement for obtaining a stable operation. This control method can realize a compressor driver having start-performance enough to overcome pressure-difference.

Abstract: An automatic garage door closing system to be used in combination with a garage door opener. The automatic garage door closing system includes a control box, a power source and a door sensor switch. The control box includes a timer. The timer has a first predetermined time period which is set by a user and activates the garage door opener to close a garage door. The timer has a second predetermined time period which is fixed and which shuts down and resets the automatic garage door closing system. The power source is connected to the control box to activate and power the control box, including the timer of the control box. The door sensor switch senses opening of the garage door and activates the power source to activate the control box.

Abstract: In a motor and a disk drive apparatus in accordance with the present invention, a position detecting part 30 comprises a detection signal switching circuit 39A, a noise elimination circuit 38 and a detection circuit 39B, and the detection signal switching circuit 39A is configured to output an inverted detection signal obtained by logically inverting a detection signal until the rotation speed reaches a predetermined rotation speed after the beginning of starting or until a position detection pulse signal FG is detected a predetermined number of times; position detection operation is carried out only during the ON operation of PWM, whereby PWM sensorless starting is carried out.

Abstract: A method for controlling voltages in an integrated starter alternator electric machine is provided where the armature windings are manipulated in a &Dgr;Y/&Dgr; fashion. In particular, the armature windings are arranged in a &Dgr; connection during engine cranking operation, when the electric machine acts as a starter motor. After the engine is cranked, the windings are changed into a Y connection when the ISAD machine changes from motoring to generating and operates a low speeds, such as idle speed. Next, when the engine speed increases above a predetermined winding reconfiguration speed, the windings are switched from Y to &Dgr; connection. If the engine speed falls below the winding reconfiguration speed, the machine again switches the armature windings to a Y connection to take advantage of the efficiencies of the Y connection at that low speed range in the generating state.

Abstract: A permanent magnet motor includes salient pole stator cores. The poles and/or linking portions therebetween are wound with a plurality of winding coil sets. Mutually exclusive speed ranges are established between startup and a maximum speed at which the motor can be expected to operate. A different number of the motor stator winding coils are designated to be energized for each speed range for maximum operating efficiency. The number of energized coils are changed dynamically as the speed crosses a threshold between adjacent speed ranges.

Abstract: The system is operable to control a robotized gearbox which includes control levers which can be displaced along at least one working line along which a plurality of nominal operating positions are defined which correspond to the speed ratios or gears and to a neutral position. The control system includes electro-mechanical actuators coupled to the control levers and operable to displace them along the said at least one working line, and an electronic control unit operable to control these actuators to operate in a predetermined manner, so as to position the control levers selectively in one of the operating positions. The control levers have associated sensors operable to supply the control unit with signals which together indicate that the levers have reached predetermined positions along the said at least one operating line.

Abstract: A hybrid electric vehicle having an energy generation system, an energy storage system and at least one, and preferable two or more, traction drive units includes a controller for controlling operation of vehicle systems. The controller may adaptively control traction by one or more traction drive units to better propel the vehicle. The controller may, for example, prevent unnecessary wheel slip, allow a traction profile to match a desired profile, and may be used to assist in turning of the vehicle. A method of adaptive control is also provided.

Abstract: A variable speed drive control system operates a variable speed drive to power a first load from a power source simultaneously powering a second load. An AC reactive power is monitored which may comprise or consist of an AC reactive power of the second load. Responsive to the monitored AC reactive power, the variable speed drive is controlled to counter the AC reactive power of the second load.

Abstract: A cooling fan includes a fan, a motor a motor coupled to the fan to drive the fan and a microcontroller. The microcontroller is connected to the motor and is capable of detecting a speed of the fan in real time and maintaining a constant speed of the fan regardless of changes in input voltage.

Abstract: An operating procedure for the motor (1) of an electric powered tool. The operating idle speed of the motor (1) is set to a value using regulator electronics (4), and the operating speed is the same as a chosen operating speed (n1). The motor (1) runs on a pre-determined and higher idle speed (n2) for cooling purposes after a specific idle time (AT), while the motor (1) runs on the pre-determined operating idle speed (n1). The engine speed is immediately set to the operating speed (n1) once again, when the motor requires a moment of strain at a certain period of time (T3) to maintain simple and comfortable operating procedures.

Abstract: A strategy to control and diagnose the operation of an electric motor using a sensorless control system augmented by feedback from a position and speed sensor is disclosed. The strategy can improve the robustness of operation and diagnose potential faults in electric motors. The present invention includes a method for diagnosing operation of an electric motor and a method and system for controlling an electric motor. In the diagnostic method, a sensorless system and a sensor based system are checked against each other to determine if either of the systems is faulted. In the control method, the sensor based control system is used when the motor speed is below a predetermined threshold and the sensorless system is used when the motor speed is above the predetermined threshold. The position sensor can be a low resolution position sensor, an engine crankshaft sensor, an engine camshaft sensor, or a transmission sensor.

Abstract: An electric working machine has an electric motor and a speed adjustment member for undergoing movement within a range of positions including a low speed range position in which the electric working machine travels at a low speed, a high speed range position in which the electric working range position in which the electric working machine travels at a speed intermediate of the low speed and the high speed. A potentiometer receives a voltage which varies in dependence on the position of the speed adjustment member within the range of positions. A control unit controls the electric motor in accordance with the variation of the voltage received by the potentiometer to vary a travel speed of the electric working machine so that a rate of change of the travel speed of the electric working machine is smaller when the speed adjustment member is in the intermediate speed range position than when the speed adjustment member is in each of the low speed range position and the high speed range position.

Abstract: A variable speed drive control system operates a variable speed drive to power a first load from a power source simultaneously powering a second load. An AC reactive power is monitored which may comprise or consist of an AC reactive power of the second load. Responsive to the monitored AC reactive power, the variable speed drive is controlled to counter the AC reactive power of the second load.

Abstract: A brush type DC motor 10 having an armature 15 and positive and negative power leads is provided. The motor includes an RFI choke 12 as a transformer in series with at least one of the positive and negative power leads to amplify current such that rotation of the armature 15 can be detected based on monitoring a voltage relating to the amplified current. Conditioning circuitry 14 is constructed and arranged to condition the voltage for detecting rotation of the armature.

Abstract: An electric motor drive controller for an electric vehicle driven by a motor with permanent excitation and powered by an energy source comprises: a power control stage coupleable to the motor for generating a drive signal at a voltage to control the motor at a desired speed; a voltage control circuit connectable between the energy source and the power control stage for controlling the voltage of the drive signal at a first voltage potential in one operating mode and at a voltage potential greater than the first voltage potential in another operating mode; and a mode controller for controlling the operating modes of the voltage control circuit based on properties of the drive signal.

Abstract: A method of controlling the speed and position of a motor includes receiving a pulse train indicative of the speed of the motor, and a periodic signal at a frequency greater than the pulse train. The number of cycles of the periodic signal per cycle of the pulse train is counted, and compared to a predetermined number. The speed of the motor is adjusted to match the count to the predetermined number, thus effecting speed control. A command position signal defining a plurality of sampling points is generated. The number of cycles of the periodic signal between a sampling point of the command position signal and an operative edge of the pulse train is counted and compared to a predetermined number. The speed of the motor is further adjusted to match the count to the predetermined number, thus effecting position control.

Abstract: A downhole compressor system is disclosed for assisting in extracting gas from the well. The system comprises a compressor 14, an electric motor 10 for driving the compressor 14 which motor has a stator winding and a rotor 12 and, in use, is lowered into the well together with the compressor. A control system 18, which when in use is disposed outside the well, is connected to the stator winding for controlling the current supply to the motor 10. The control system 18 receiving a signal indicative of the speed and phase of the rotor from a feedback sensor 16 mounted for rotation with the rotor 12. In the invention, the feedback sensor is a current generator having a permanent magnet 16a mounted for rotation with the rotor 12 and a second stator winding 16b connected to the control system 18.

Abstract: A motor control method and a motor control system are provided which control a motor using an acceleration command and an estimated inertia moment of a motor. The motor control method for a parallel hybrid electric vehicle according to the preferred embodiment of the present invention comprises calculating an estimated inertia moment of a motor, calculating a forward compensation current based on the estimated inertia moment and an acceleration command, calculating a final current command based on a speed controller output current and the forward compensation current, the speed controller output current being calculated based on the acceleration command, and controlling the motor using the final current command.

Abstract: A method of transitioning a motor from a torque control mode to a speed control mode includes providing the motor with a torque command to eliminate torque holes at the transition. A speed controller generates a speed error, which is used to generate two torque terms. The first torque term is proportional to the speed error, and the second torque term includes the integral of the speed error. A third torque term comprises a feedforward torque, which is added to the first two torque terms to generate the torque command.

Abstract: There is provided a brushless DC fan motor which can eliminate an oscillator for PWM, control the motor speed at a low cost with high accuracy, and efficiently adjust the temperature in a housing for electronic appliances when radiating the heat in the housing. The brushless DC fan motor with the rotational speed thereof controlled by controlling the voltage of a control input terminal of a drive circuit comprises a differential amplifier in which the voltage signal for controlling the speed is inputted in a first input terminal and the reference voltage signal is inputted in a second input terminal. The differential amplifier is linear in the input-output characteristic, and can set the rise characteristic of a desired gradient, and control the motor speed with high accuracy without using the PWM signal for the input signal. The voltage signal from the output terminal of the differential amplifier is given to the control input terminal of the drive circuit.

Abstract: A drive control method includes detecting an angular displacement of a rotor driven by a pulse motor, calculating a difference between the detected angular displacement and a preset target value of the angular displacement, and calculating a drive pulse frequency of a drive pulse signal used to drive the pulse motor. The pulse motor is driven by the drive pulse signal having the drive pulse frequency to allow the rotor at a constant angular velocity.

Abstract: A method for controlling heat dissipation of an electronic device, such as a central processing unit, by controlling rotational speed of a fan and supplying a clock signal with slower clock frequency to the electronic device is disclosed. The fan rotates at a speed in proportion to the temperature of the electronic device when the temperature of the electronic device is below a maximum reference temperature. The fan rotates at a maximum rotational speed when the temperature of the electronic device is beyond the maximum reference temperature. The fan rotates at a maximum rotational speed and a clock signal with slower clock frequency is supplied to the electronic device when the temperature of the electronic device is beyond both the maximum reference temperature and a slowing-clock starting reference temperature, until the temperature of the electronic device drops below a slowing-clock ending reference temperature.

Abstract: A method of transitioning a motor from a torque control mode to a speed control mode includes providing the motor with a torque command to eliminate torque holes at the transition. A speed controller generates a speed error, which is used to generate two torque terms. The first torque term is proportional to the speed error, and the second torque term includes the integral of the speed error. A third torque term comprises a feedforward torque, which is added to the first two torque terms to generate the torque command.