Abstract: A direct current (DC) electric motor assembly with a closed type overlap stator winding which is commutated with a timed commutating sequence that is capable of generating a stator rotating magnetic field. The coil overlap of the winding and a timed commutation sequence are such that the current in each slot of the stator is additive and when a previous magnetic pole collapses according to a commutation sequence; the energy released by that previous collapsing magnetic field is captured to strengthen the next magnetic field on the commutation sequence schedule. Electrical currents produced by the collapsing magnetic fields flow to low electric potential and add or subtract to the DC current provided by the commutator thus promoting formation of the next magnetic on commutation schedule. When used with a suitable commutator and rotor, the electric motor assembly provides a true brushless high torque speed controlled Real Direct Current (RDC) motor that operates with higher efficiency and higher power density.

Abstract: A system includes a vehicle having a motive electrical power path; a power distribution unit comprising a current protection circuit disposed in the motive electrical power path, the current protection circuit comprising a thermal fuse and a contactor in a series arrangement; a current source circuit electrically coupled to the thermal fuse and structured to determine that a load power throughput of the motive electrical power path is low, and to inject a current across the thermal fuse in response to the load power throughput of the motive electrical power path being low; a voltage determination circuit electrically coupled to the thermal fuse and structured to determine at least one of an injected voltage amount and a thermal fuse impedance value; and wherein the current source circuit determines the load power throughput of the motive electrical power path is low in response to the vehicle being in a shutdown state.

Abstract: A system includes a vehicle including a power distribution unit comprising a current protection circuit disposed in a motive electrical power path with a thermal fuse and a contactor in a series arrangement; a current source circuit electrically coupled to the thermal fuse to determine that a load power throughput is low, and to inject a current across the thermal fuse in response to the load power throughput being low; a voltage determination circuit electrically coupled to the thermal fuse to determine an injected voltage amount and/or a thermal fuse impedance value; where the power distribution unit further includes a plurality of fuses, and where the current source circuit is structured to inject the current across each fuse in a selected sequence; and where the current source circuit injects the current across a first and second fuse of the plurality of fuses at a first shutdown event.

Abstract: A motor control system has a computing device and a motor controller. The computing device receives user demands through a GUI, and provides a preset speed table based on the user demands. The preset speed table has a plurality of fixed values of a duty cycle of a pulse width modulation signal and a plurality of preset values of a preset motor speed corresponding to the plurality of fixed values of the duty cycle of the pulse width modulation signal. The motor controller provides the pulse width modulation signal to drive a motor based on the preset speed table.

Abstract: A rotary system includes a rotor, a vector-based position sensor, and a controller executing a method to eliminate fundamental harmonic position measurement error. The sensor measures angular position of the rotor and outputs raw sine and cosine signals representative of the angular position. The raw signals have a fundamental harmonic position measurement error at the frequency of the sensor signals. The controller receives the raw signals, adaptively adds or subtracts sensor signal offsets to or from the raw signals to generate offset sine and cosine signals, calculates a corrected position of the rotor using the offset sine and cosine signals eliminating the fundamental error, and controls an action or state of the rotary system using the corrected position. The rotor may be part of an electric machine, such as in a vehicle.

Abstract: A brushless direct current motor for a power tool. The motor includes a stator assembly including a stator core having stator laminations with an annular portion and inwardly extending stator teeth. The motor also includes a rotor assembly including a rotor core having rotor laminations and defining a central aperture that receives an output shaft. The rotor assembly also includes a rotor end cap on a first side of the rotor core having a bearing holder and defining a channel, wherein the channel is open on a side of the rotor end cap facing the rotor core. The motor further includes a bearing provided in the bearing holder that couples the rotor end cap to the output shaft and a position sensor board assembly provided in the channel of the rotor end cap and configured to provide position information of the rotor core to a motor controller.

Abstract: An encoder includes a positional information generation unit configured to generate first positional information based on a detected signal which is output by a sensor unit, and an IIR filter unit configured to output second positional information obtained by performing filtering on the first positional information. In the IIR filter unit, a counter unit stores a predetermined high-order digit of the first positional information as a count value, and an input unit subtracts the count value from the first positional information to thereby generate input information. A computation unit generates an internal computation result based on delay information which is an internal computation result stored in a delay information storage unit, input information, and a predetermined filter coefficient, and generates output information on which filtering is performed. An output unit adds the count value and the output information to thereby generate second positional information.

Abstract: A communication apparatus, which has a normal power consumption mode and a power saving mode lower in power consumption than in the normal power consumption mode and which is connected to a network via a network interface device, communicates with a device on the network via the network interface device. The communication apparatus acquires capability information indicating a communication capability of the device, and based on acquired capability information, determines a communication mode to be used when the network interface device communicates with the device under a condition that the communication apparatus has shifted to the power saving mode, and when the communication apparatus shifts from the normal power consumption mode to the power saving mode, sets the determined communication mode as a communication mode to be used when the network interface device communicates with the external device.

Abstract: A surrogate foam test system for testing a foam distribution system of a fire fighting vehicle includes a water tank having an outlet coupled to a flush line and a foam storage tank having an outlet coupled to a foam feed line. The water tank provides water through the outlet and the foam storage tank provides a foam fire suppressant. The test system also includes a flush valve coupled to the flush line, where the flush line extends through the flush valve and into the foam feed line at a junction, and a foam valve coupled to the foam feed line before the junction, where the foam feed line extends through the foam valve and accepts the flush line the junction. A flow meter is coupled to the flush line between the flush valve and the junction, where the flow meter is configured to monitor a flow rate of the water within the flush line.

Abstract: A method for controlling a motor is provided. The method comprises obtaining electrical signals of the motor with a signal unit, the electrical signals comprising a motor torque and an angular velocity, calculating a voltage phase angle of a voltage vector with a calculating component, wherein a command torque, the motor torque, the angular velocity and a voltage amplitude of the voltage vector are inputs of the calculating component, and wherein the voltage phase angle is a variable and the voltage amplitude is a constant. The method further comprises modulating the voltage phase angle and the voltage amplitude to a switching signal for controlling an inverter; converting a direct current voltage to the voltage vector according to the switching signal, and applying the voltage vector to the motor.

Abstract: An apparatus or method which accepts a burst of pulses at a frequency which may not be tightly controlled and converts this into a trajectory command that is a suitable motion profile for an incremental motor control application. The output of the invention can be a pulse stream that can be fed to an existing incremental pulse input motor drive or the invention can be embedded into a motor drive where its output is a numerical sequence that defines a physically realizable trajectory to be fed to the control circuits and software within the motor drive.

Abstract: Assemblies for HVAC systems and methods of operating HVAC systems are disclosed, including a method of operating an HVAC system having a compressor assembly and a condenser assembly. The compressor assembly includes a compressor having a compressor motor that is susceptible to backspinning and capable of generating electric power when backspinning. The condenser assembly includes a condenser motor operatively coupled to a fan. The condenser assembly is electrically coupled to the compressor assembly. The method includes using the condenser motor as an electric load to dissipate electric power generated by the compressor motor when the compressor motor backspins.

Abstract: A detection control system includes a sensing unit, a control module and a driving module for a motor including a rotor and a stator. The sensing unit electrically connects the motor to sense a first and a second magnetic pole of the rotor cross a chip disposed between the rotor and the stator; a third magnetic pole is alternated to a forth magnetic pole of the stator to generate a sensing signal. A detection unit of the control module detects a kickback voltage value generated by a first current value changing to a second current value to calculate a minimum current value to generate a detecting signal. A timing unit receives the sensing and the detecting signal to calculate a first and a second period of time, and a discharging time. The driving module drives the rotor by receiving a control signal the control unit generates by controlling an alternating time.

Abstract: A circuit includes a comparator having input terminals configured to be coupled across a drive transistor adapted to drive a phase of a motor. The comparator senses a drive current of the motor phase, said sensed drive current represented by a periodic signal whose period is indicative of motor speed. A motor speed calculation circuit receives the periodic signal and processes the periodic signal to determine a speed of the motor.

Abstract: A computer-implemented fan control method includes measuring a temperature within a computer system and dynamically selecting a fan speed step in response to the temperature received, wherein the fan speed step is selected from a fan speed table defining a finite number of fan speed steps each having an associated fan speed. A fan is operated at the dynamically selected fan speed step, wherein the fan is positioned to drive air through the computer system where the temperature is being measured. The fan output variation is measured over a prescribed time interval and the fan speed table is automatically modified to change the fan speeds associated with each fan speed step, wherein the fan speeds are changed as a function of the measured fan output variation while continuing to drive the fan.

Abstract: A power converting apparatus including a power converter that converts a DC voltage into an AC voltage and applies the AC voltage to an AC rotating machine and a control unit that controls the power converter based on an operation command from the outside is provided. The power converting apparatus includes: a first calculating unit that calculates and outputs, from a d-axis current detection value and a q-axis current detection value detected by the AC rotating machine and current command values based on the operation command, first voltage command values to the power converter, magnetic fluxes of the AC rotating machine, and an angular frequency; and a second calculating unit that sets, as an initial value, at least one of the magnetic fluxes and the angular frequency input from the first calculating unit and calculates and outputs second voltage command value to the power converter and an angular frequency.

Abstract: The present invention relates to a drive apparatus and drive method for switching an energization mode when a voltage of a non-energized phase of a brushless motor crosses a threshold. In threshold learning, first, the brushless motor is stopped at an initial position. The brushless motor is then rotated by performing phase energization based on the energization mode from the stopped state. The voltage of the non-energized phase at an angular position of switching the energization mode is detected from a maximum value or a minimum value of the voltage of the non-energized phase during the rotation, and the threshold is learned based on the detected voltage. Alternatively, the brushless motor is positioned at the angular position of switching the energization mode by maintaining one energization mode, and then the energization mode is switched to the next energization mode.

Abstract: An electric motor, having a stator (465), a rotor (470), and an apparatus for evaluating a signal provided for controlling said motor (110), comprises a receiving unit (430, 440) for receiving a control signal (PWM_mod), which is a pulse width modulated signal (PWM) onto which a data signal (DIR, DATA) is modulated. An evaluation unit (440) is provided for evaluating the modulated control signal (PWM_mod). The unit is configured to extract, from the modulated control signal (PWM_mod), data provided for operation of the motor (110). The control apparatus includes a signal generator (450) configured to generate, on the basis of the extracted or ascertained data provided for operation of the motor (110), at least one control signal for the motor (110), such as a commanded direction of rotation. Piggybacking other control data onto the PWM power level signal reduces hardware investment, by permitting omission of a signal lead which would otherwise be required in the motor structure.

Abstract: A driving system for a fan that enables an increase in motor current that may be supplied to excitation windings at the time of a maximum static pressure without increasing the rotational speed excessively when an amount of maximum air flow is provided. The fan driving system includes a drive signal generating circuit that generates drive signals, a motor driving circuit that supplies a motor current to the motor in accordance with the drive signals, a current detecting circuit (resistance) that detects the motor current, and a drive signal changing circuit. The drive signal changing circuit changes the drive signals generated by the drive signal generating circuit to restrict an increase in the motor current when the motor current becomes larger than a threshold.

Abstract: In an imaging apparatus having a toner container, a method of periodically calibrating a back EMF constant Ke used in a speed control circuit of a DC motor used for driving for a toner metering device. To adjust the value of the back EMF constant Ke, the method uses a plurality of sampled back EMF measurements together with a calculated actual speed of rotation of the toner metering device as measured using motion sensor.

Abstract: A method and a device for controlling and/or regulating an electric motor. Such electric motors are used for example in motor vehicles in the form of pump motors. In general, the electric motor is supplied with electrical energy from a battery and/or using a generator. The controlling and regulation take place using a high-frequency pulse width modulation (PWM). When the electric motor is started, the PWM is used to continuously increase the motor current required for the operation of the electric motor, e.g. beginning from 0.

Abstract: A control system for an electric machine, the control system including a position sensor and a drive controller. The drive controller generates one or more control signals for exciting a winding of the electric machine in response to edges of a signal output by the position sensor. Moreover, the drive controller generates control signals in response to an edge that occurs within a time window. The time window starts at a time when control signals are generated and has a length less than the electrical half-cycle period.

Abstract: A motor drive circuit is configured to drive a motor coil based on duty ratio of a PWM signal, and includes a first pulse signal generating circuit configured to generate a first pulse signal for each time period, the time period being equal to 1/n of a time period during which the PWM signal is at one logic level, a counter configured to change a count value based on the first pulse signal, a drive signal output circuit configured to output a drive signal of one logic level when the count value is not a predetermined value and output the drive signal of the other logic level when the count value reaches the predetermined value, a drive circuit configured to perform PWM driving for the motor coil based on the duty ratio of the drive signal, and a setting circuit.

Abstract: There are provided a command speed calculation means (101) for outputting a command speed (?r) from a base speed (?b) and a ratio gain (?), reference speed generation means (108) calculating a reference speed (?a) so as to follow the command speed (?r) based on the command speed (?r), control deviation calculation means (103) for outputting a control deviation (e) from a speed deviation (?e) and a speed deviation correction value (?ec), speed control means (104) for outputting a compensation torque (?m) for decreasing the control deviation (e), speed deviation correction means (105) for calculating the speed deviation correction value (?ec) from at least the compensation torque (?m), command torque calculation means (107) for outputting a command torque (?r) from at least the compensation torque (?m) and ratio calculation means (102) for calculating the ratio gain (?) from the speed deviation (?e).

Abstract: The present invention relates to a synchronous control apparatus for speed-reducing DC motor, comprising a speed-reducing DC motor and a controller, wherein said speed-reducing DC motor comprises a motor and a speed reducer. Said speed-reducing motor is equipped with a speed detecting module to detect the actual rotational speed. Said controller is equipped with a storage unit to save reference rotational speed values. Said speed detecting module is linked to the controller which can vary the supply voltage to the speed-reducing DC motor while the actual rotational speed differs from the reference speed value.

Abstract: A method for ascertaining measured values in a cyclically controlled system, the cyclic control having control time periods in which the system is controlled, and no-control time periods in which the system is not controlled, having the following operations of determining first integration time periods as a function of the cyclic control, the first integration time periods being situated within at least one of the control time periods, and/or determining second integration time periods as a function of the cyclic control, the second integration time period being situated within at least one of the no-control time periods; detecting one of the measured variables of the system dependent on the control; ascertaining summation and/or integration values by summation and/or integration of the measured variable during the first and/or second integration time periods; ascertaining the measured value for at least one of the control time periods and/or no-control time periods on the basis of time data of the first and/

Abstract: A rotation speed control circuit for controlling a rotation speed of a fan includes: a rotation speed detector, for generating a rotation speed voltage according to a rotation speed signal corresponding to the rotation speed; a sample and hold element, coupled to the rotation speed detector, for sampling and storing the rotation speed voltage; an error amplifier, coupled to the sample and hold element, for controlling a voltage of a filter capacitor according to the rotation speed voltage and a reference voltage, to adjust an error voltage; and a pulse width modulation signal generator, coupled to the filter capacitor, for generating a pulse width modulation signal according to the error voltage and a triangle wave.

Abstract: A fan speed control circuit includes a voltage input terminal, a thyristor, a thermistor, and first and second switches. The terminal is grounded through a first resistor and the thermistor, connected to an anode of the thyristor, and connected to a second terminal of the second switch through a second resistor. A node between the resistor and the thermistor is connected to a control terminal of the first switch. A second terminal of the first switch is grounded. A first terminal of the first switch is connected to a control terminal of the thyristor through a third resistor. A fourth resistor is connected between the anode and control terminal of the thyristor. A control terminal of the second switch is connected to the control terminal of the thyristor. A first terminal of the second switch is connected to a cathode of the thyristor and a voltage pin of a fan.

Abstract: A fan control system for controlling a fan to dissipate heat from an electronic device includes a current detection circuit having a shunt resistor to receive current, a signal amplification circuit having an operational amplifier, and a switch circuit having an npn transistor and a pnp transistor. A first terminal of the shunt resistor is connected to the electronic device, a second terminal of the shunt resistor is connected to the electronic device via a power source and is grounded. A non-inverting terminal of the operational amplifier is connected to the first terminal of the shunt resistor, an inverting terminal of the operation amplifier is connected to the second terminal of the shunt resistor via a first resistor and connected to an output terminal of the operational amplifier via a second resistor. The output terminal of the operation amplifier is grounded via a third resistor and a sixth resistor.

Abstract: A fan controlling circuit is provided. The fan controlling circuit includes an integral unit, an operational amplifier, a PMOS transistor, and an NMOS transistor. The integral unit transforms pulse width modulation (PWM) signals to voltages, and transmits the voltages to positive and negative input terminals of the operational amplifier. The PMOS transistor is coupled between a first PWM signal and an output terminal, and a gate of the PMOS transistor is coupled to an output of the operational amplifier. The NMOS transistor is coupled between a second PWM signal and the output terminal, and a gate of the NMOS transistor is coupled to the output of the operational amplifier. The fan controlling circuit may be formed by discrete elements and use a same voltage source as fans, so that the design cost and complexity are reduced.

Abstract: The present invention belongs to power generation field. It relates to a method for improving cooling capacity of a power station direct air-cooling system and the cooling system thereof. According to the present invention, a transformer in a cooling system is connected to a voltage of the power grid and outputs a voltage to an electric motor, so that its working voltage reaches 380-390V; a frequency of 40-47 HZ is output from a frequency converter in the cooling system to the electric motor; a fan is driven by the electric motor working under 380-390V and 40-47 HZ to rotate according to a set velocity ratio with the aid of a speed reducer, and cooling wind is delivered by the rotating fan head-on to a heat radiator. The present invention can be widely applied in rebuilding of existing direct air-cooling units, or designing of new power station direct air-cooling systems.

Abstract: A fan controlling circuit is provided. The fan controlling circuit includes an integral unit, an operational amplifier, and an output unit. The integral unit transforms pulse width modulation signals to voltages, and then the output unit outputs one of the pulse width modulation signals having a higher operation frequency according to the comparison result between the voltages. As the fan controlling circuit may be constituted with discrete elements and use a same voltage source as fans, the design cost and complexity are reduced.

Abstract: When cooling operation or dehumidifying operation is started, a blower fan for an evaporator and an exhaust fan for a condenser are driven at an initial rotational number. A compressor is driven at a fixed rotational number. Due to load variation, an operating current supplied from a power source is changed. When the operating current exceeds a reference value, the rotational number of the blower fan is gradually reduced. When an endothermic quantity by the evaporator decreases, a temperature of a gas refrigerant flowing through the evaporator is lowered. Since the load applied on the compressor is reduced, the operating current decreases. In this way, when the compressor is loaded, the operating current increased, however, by controlling operation of the fans as described above, it is possible to prevent that the power source is shut off due to overcurrent and operation is stopped.

Abstract: A rotating speed adjustment circuit for a heat dissipation fan includes a first node, a second node, a reception end for receiving a first control signal, a first resistor coupled to a voltage source and the first node, a second resistor coupled to the first node and the second node, a third resistor coupled to the second node and a ground end, a capacitor coupled to the first node and the ground end, a transistor coupled to the reception end, the second node and the ground end, an oscillator for generating an oscillating signal, and a comparator for comparing a signal of the first node and the oscillating signal, so as to output a second control signal to control a rotating speed of the heat dissipation fan.

Abstract: A system including an error signal generating module to generate an error signal based on (i) back electromotive force sensed from a motor and (ii) a predetermined speed of the motor. The error signal includes noise due to mismatched poles of the motor. A noise elimination module eliminates components of the noise having frequencies N times a frequency of rotation of the motor from the error signal and generates a corrected error signal, where N is an integer greater than or equal to zero. A control module generates a first control signal based on components of the corrected error signal, generates a second control signal based on components of the error signal, and rotates the motor at the predetermined speed based on (i) the first control signal and (ii) the second control signal. The components of the corrected error signal have higher frequencies than the components of the error signal.

Abstract: A method for ascertaining measured values in a cyclically controlled system, the cyclic control having control time periods in which the system is controlled, and no-control time periods in which the system is not controlled, having the following operations of determining first integration time periods as a function of the cyclic control, the first integration time periods being situated within at least one of the control time periods, and/or determining second integration time periods as a function of the cyclic control, the second integration time period being situated within at least one of the no-control time periods; detecting one of the measured variables of the system dependent on the control; ascertaining summation and/or integration values by summation and/or integration of the measured variable during the first and/or second integration time periods; ascertaining the measured value for at least one of the control time periods and/or no-control time periods on the basis of time data of the first and/

Abstract: A motor rotational speed control device for controlling a direct current (DC) brush motor is provided, which includes a motor driver, a detection unit and a central processing unit (CPU). The motor driver is coupled to a first control terminal and a second control terminal of the DC brush motor. The detection unit detects a back electromotive force (EMF) of the DC brush motor through the first control terminal and the second control terminal when the motor driver is set to a disable state, and accordingly generates back EMF information. The CPU determines whether the direct current brush motor has stopped rotating according to the back EMF information, and determines whether to generate a brake control signal according to a determination result. The motor driver reduces a rotation speed of the DC brush motor according to the brake control signal when the motor driver is set to an enable state.

Abstract: A drilling device prevents recurrence of an overload condition after occurrence of the overload condition, thereby improving operability and safety in the drilling device. A motor for rotating a drill is connected to an AC power source through a motor control unit, a current detector, and a power switch. A magnet is also connected to the AC power source through the power switch and a full-wave rectifier. The motor control unit rotationally drives the motor on the basis of a signal sent from a main control unit according to a state in which a motor start switch is on. The main control unit controls the motor control unit to gradually reduce a supply voltage to the motor when the motor becomes overloaded, to gradually increase the voltage to the normal power supply condition when the overload condition is vanished, and to stop power supply to the motor if the overload condition continues for a predetermined period.

Abstract: An aspect of the invention is a method and a device for controlling a rotating field machine having several phase windings, which can be controlled by means of pulse width modulation, wherein a pulse width modulation controller is adapted in such a way that an individual winding of the phase windings of the rotating field machine is energized at a specifiable sampling time.

Abstract: An electrically driven fan arrangement, suitable for energy-conserving installations, includes a fan, an electric motor (110) serving to drive the fan, and associated control apparatus, namely: a sensing apparatus (140) for sensing a volumetric air flow rate (125) generated by the fan (120) and for generating a measured volumetric air flow value (Vmess), and a volumetric flow rate control arrangement (160) for automatically controlling the volumetric air flow rate (125) generated by the fan (120) to a predetermined target volumetric air flow value (V_s). The volumetric flow rate control arrangement (160) is configured to generate a target rotation speed value (N_s) for the electric motor (110). A rotation speed controller (170), which automatically controls the rotation speed of the electric motor (110) to the target rotation speed rate (N_s) generated by the volumetric flow rate control arrangement (160), is also provided.

Abstract: A controller of a brushless DC electric machine having a rotor and at least a stator winding powered by a driving voltage is provided. The controller includes a position sensor, an advance angle control circuit, and a driving circuit. The position sensor is moved along a reverse rotating direction of the rotor by a prepositioned angle for outputting a position signal. The advance angle control circuit receives the position signal and a driving voltage reproduction signal reproduced from the driving voltage and outputs a commutation control signal lagging the position signal by a first delay time. The driving circuit receives the commutation control signal for outputting a driving signal for controlling a commutation of the brushless DC electric machine.

Abstract: In order to prevent a short circuit of top and bottom arms of a motor driving IC when noise is added to six control signals for controlling six switching elements, there is provided a semiconductor device for driving a motor, being sealed with resin as one package and comprising: six switching elements for driving a three-phase motor; three output terminals for outputting voltages to the three-phase motor; at least one driving circuit for driving the six switching elements; three control signal input terminals; and a function) of generating six control signals for control of the six switching elements based on three control signals inputted through the three control signal input terminals.

Abstract: A drive system for an electrical machine is provided. The system includes a control unit and a monitoring unit, which is independent of the control unit. The control unit includes a device that converts one or more incoming operating parameters of the electrical machine to an output value. The monitoring unit includes a device that converts the operating parameters to a comparison value, with the conversion being carried out more quickly in the control unit than in the monitoring unit. A comparator compares the output value or an intermediate value of the output value with the comparison value of the output value or of the intermediate value.

Abstract: A power converter circuit for providing maximum utilization of a DC bus voltage to a two-phase Permanent Magnet Synchronous Motor (PMSM) is disclosed. The circuit includes first, second, and third nodes, each node being the junction between series connected high and low side switches connected across a DC bus; a PMSM having first and second windings and a star point at which the first and second windings are coupled to each other, the first winding having a terminal connected to the first node, the second winding having a terminal connected to the second node, and the star point being connected to the third node; and a controller for performing a three-point Pulse Width Modulation (PWM) coupled to a gate of each switch.

Abstract: A switch-type power converter comprising an PET switch operating in a variable duty cycle mode under the control of a Unitrode 3846 integrated circuit controller. Indications of excess input voltage and reverse battery connections are provided by circuits including an element which permanently changes state. A cooling fan mounted on a finned heat sink is operated in a variable speed mode. A single thermistor sensor provides inputs to both the fan speed control and a thermal shutdown circuit connected to shut down the gate drives to the FET switch in the event of a high temperature condition. Another shutdown function is provided in response to an input overvoltage condition by way of an operational amplifier. The converter uses foldback for short circuit protection and is compatible with microprocessor units to selectively provide multiple output voltage levels.

Abstract: According to some preferred embodiments of the present invention, a motor driving circuit includes a phase detection circuit configured to detect a rotation phase of a motor and output a phase detection signal, a first amplifier configured to amplify the phase detection signal and output an amplified detection signal, and a second amplifier configured to amplify the amplified detection signal in accordance with a power supply voltage and output a driving signal to the motor. The motor driving circuit is further provided with a controlling circuit configured to detect the power supply voltage and increase/decrease amplitude of the amplified detection signal outputted from the first amplifier in response to an increase/decrease of the detected power supply voltage, whereby heat generation and noise generation can be restrained, irrespective of the increase/decrease of the power supply voltage.

Abstract: A motor controller calculates a motor torque command based on motor speed and causes a motor to generate a torque corresponding to the motor torque command, to drive a machine load coupled to the motor. The motor controller includes a speed compensator that makes, when a speed compensation torque is calculated based on the motor speed, frequency characteristics of the speed compensation torque for the motor speed exhibit a low frequency cutoff characteristic so that steady-state gain in frequency response is less than a maximum gain value. A torque adder generates a motor torque command by adding to the existing motor torque command an externally input feedforward torque signal and the speed compensation torque.

Abstract: A hand-guided or stationary power tool has a drive unit having a motor that includes a rotor having a permanent magnet and a stator and has a motor control designed to trigger the motor in a first rotational speed range according to a voltage-controlled mode and to trigger the motor in a second rotational speed range following the first rotational speed range in the direction of a higher rotational speed according to a field-weakening operation.

Abstract: A fan rotation speed control circuit of a power supply system is provided, which is applicable for controlling the rotation speed of the fan according to a loading state outputted by the power supply system. The fan rotation speed control circuit of the power supply system includes a waveform generating module, for generating an oscillating waveform signal; a current retrieving module, for retrieving a current signal corresponding to the loading state; a rotation speed control signal generating module, for comparing the oscillating waveform signal with the current signal, and generating a rotation speed control signal; a signal amplifying module, for amplifying an amplitude of the rotation speed control signal and outputting the amplified rotation speed control signal to the fan, so as to control the rotation speed of the fan.

Abstract: A method of constant airflow control for a ventilation system is disclosed. The method includes various controls to accomplish a substantially constant airflow rate over a significant change of the static pressure in a ventilation duct. One control is a constant I·RPM control, which is primarily used in a low static pressure range. Another control is a constant RPM control, which is primarily used in a high static pressure range. These controls requires neither a static pressure sensor nor an airflow rate sensor to accomplish substantially constant airflow rate while static pressure changes. This is because these controls use only intrinsic control variables which are electric current and rotational speed of the motor. Also, the method improves the accuracy of the control by correcting certain deviations that are caused by the motor's current-RPM characteristics. To compensate the deviation, the method adopts a test operation in a minimum static pressure condition.