Abstract: A circuit includes a first rectifier having a first rectifier input and a first rectifier output. The circuit also includes a bridge circuit and a second rectifier. The bridge circuit is coupled to the first rectifier output. The bridge circuit has first, second, third, and fourth terminals. The first and second terminals are coupled to the first rectifier output, and the third and fourth terminals are adapted to be coupled to a primary winding of a transformer. The second rectifier has a second rectifier input and a second rectifier output. The second rectifier input is adapted to be coupled to a secondary winding of the transformer.

Abstract: A stepping motor control device is provided, which controls a stepping motor including a rotor position detector by micro-step driving. The control device has a plurality of operation modes including an adjustment mode and a use mode. In the adjustment mode, the control device generates control data for a closed loop control for controlling the winding current of the stepping motor based on the detection value of the rotor position detector, and performs a stepping motor acceleration operation and a stepping motor deceleration operation according to the control data. In the use mode, the control device performs the stepping motor acceleration operation and the stepping motor deceleration operation so that a winding current observed in the adjustment mode is reproduced by an open loop control for controlling the winding current of the stepping motor based on the control data generated in the adjustment mode.

Abstract: A method of controlling a dual wound synchronous machine (DWSM) includes: determining virtual current commands based on a current command associated with each of two winding sets of the DWSM; determining virtual half-motor currents by applying a mathematical transformation on measured output currents; determining half-motor difference currents based on differences between the corresponding virtual current command and the virtual half-motor current; calculating forward path voltage commands based on the corresponding difference currents and using first and second gain factors; determining feedback voltage commands by applying third and fourth gain factors to the virtual half-motor currents; determining virtual final voltage commands based on the corresponding forward path and feedback voltage commands; determining final voltage commands by applying a second mathematical transformation to the virtual final voltage commands; commanding, based on the final voltage commands, inverters to apply corresponding voltag

Abstract: An electromechanical watch including an electromechanical motor (4) mechanically coupled to an analogue display (AD) and formed by two coils (B1, B2) through which the magnetic circuit (10) of the stator passes. A first of the two coils is connected to a voltage detection circuit (CD1, CD2) arranged to be able to detect any voltage induced in this first coil during intervals of time occurring, in a stepping functioning mode of the motor, between drive pulses to detect whether an unwanted step is made by the rotor (18) during these intervals of time. The electromechanical watch includes at least one switch (T1, T2, T3) that is controlled by an electronic control circuit (CEC) to short-circuit the second coil during each of said intervals of time, in order to passively hold the rotor in the idle position in which it is situated momentarily between the drive pulses.

Abstract: In some examples, an apparatus operable to drive a motor includes driver circuitry adapted to be coupled to the motor and processing logic coupled to the driver circuitry. The processing logic is operable to determine an expected current for controlling the motor, reduce a reference current upon which the motor is controlled from a first value to a second value at an exponential rate, determine that a measured current of the motor is approximately equal to the expected current, and responsive to determining that the measured current of the motor is approximately equal to the expected current, provide a control signal to the driver circuitry based on the expected current to the motor to control the motor to operate according to closed loop control.

Abstract: A motor driving apparatus of driving a motor including a plurality of windings respectively corresponding to a plurality of phases is disclosed The motor driving apparatus includes a first inverter including a plurality of first switching elements and connected to a first end of each of the windings, a second inverter including a plurality of second switching elements and connected to a second end of each of the windings, and a controller connected to the first switching elements and the second switching elements and configured to determine an effective vector closest to a voltage vector corresponding to a preset voltage command of the motor as a duty of the plurality of second switching elements and to control pulse width modulation of the first switching elements using a value obtained by adding the effective vector corresponding to the duty of the second switching elements to the voltage command of the motor as a voltage command of the first inverter.

Abstract: A method for electrically producing a stalled state in a stepper motor having a first coil and a second coil is provided. The method includes driving a first sinusoidal current through the first coil, and driving a second sinusoidal current through the second coil, wherein the first and second sinusoidal currents are in phase.

Abstract: Provided is a method of producing an ultrafine bubble-containing liquid containing ultrafine bubbles generated by causing film boiling in a liquid with a heat generation member, including: detaching a solid present at a liquid contact surface of the heat generation member in a form of a microscopic substance by using the film boiling; and generating ultrafine bubbles with the detached microscopic substance as a core.

Abstract: A method includes generating a first feedforward signal based, at least in part, on a sensor signal. The method further includes generating a second feedforward signal based, at least in part, on a feedforward seek table. A control signal is modified based, at least in part, on the first feedforward signal and the second feedforward signal. A position of an actuator is controlled in response to the modified control signal.

Abstract: A motor drive control device includes a control unit generating a control signal Sd such that one-phase excitation of exciting, of coils and of two phases of a two-phase stepping motor, a coil for one phase and two-phase excitation of exciting the coils for two phases are alternately repeated, and a drive unit driving the coils of two phases based on the control signal Sd. An energization angle ? representing a magnitude of an electric angle for continuously energizing the coil of one phase in one direction is capable of being set in the control unit. Specifically, the control unit determines a period T1n for performing the one-phase excitation based on a back electromotive voltage generated in the coil non-excited in the one-phase excitation, and determines a period T2n for performing the two-phase excitation based on an elapsed time per unit angle while the two-phase stepping motor is being excited and the energization angle ?.

Abstract: A refrigerated display case having a housing defining a temperature controlled space and a refrigeration system coupled to the housing is provided. The refrigeration system is configured to be operable to affect a temperature of the temperature controlled space. The refrigeration system includes an actuator, a controller, and a sensor. The controller is configured to continuously update a stored position of the actuator based on measurement of an electric current provided to the actuator, retrieve the stored position after a power failure, and restart control based on the stored position of the actuator. The sensor is configured to communicate with the controller.

Abstract: A shift range control apparatus switches a shift range by controlling a motor. The shift range control apparatus includes an angle calculator, a speed calculator and a drive controller. The angle calculator calculates a motor angle based on a detected value of a rotational angle sensor. The speed calculator calculates a motor rotational speed based on the detected value of the rotational angle sensor. The drive controller executes a stationary phase energization control to stop the motor in response to the motor angle reaching a stationary phase energization start position. The drive controller sets a stationary energization phase being a stationary phase of the motor in the stationary phase energization control, according to the motor rotational speed when the motor angle reaches the stationary phase energization start position.

Abstract: A device for damping vibrations in a structure including a first (or inner) element rotatably mounted around a rotational axis and a second (or outer) element rotatably mounted around said rotational axis. A radius (R1) of a circle portion delimitating the first element with respect to the rotational axis, being smaller than a radius (r2) of a circle portion delimitating the second element with respect to the rotational axis.

Abstract: The disclosure relates to a stator for a rotating electrical machine. The stator includes: a laminated core which provides stator teeth with respect to an air gap of the rotating electrical machine, and a stator winding which has a plurality of tooth windings, wherein a respective one of the tooth windings is arranged on a respective one of the stator teeth and has a respective first electrical conductor arranged in a plurality of turns running around the respective stator tooth. The disclosure is based on the object of improving the electrical safety with respect to short circuits in the region of the stator winding. It is proposed that the respective tooth winding has a respective second electrical conductor which is electrically insulated from the first electrical conductor and has a plurality of turns arranged in a manner running around the respective stator tooth, wherein the respective turns of the first and second electrical conductors are arranged in a bifilar manner.

Abstract: A vehicle includes a multi-core processor having first, second, and cores and having first and second analog-to-digital converters (ADC) associated with the first and second cores, respectively. The first and second ADC are configured to convert analog phase currents to first and second digital phase current values, respectively. The multi-core processor is configured to generate first and second rotor-angle data from digital signals representing a position of the electric machine. The processor is programmed to, via the first core, estimate a first output torque of the electric machine based on the first rotor-angle data and the first digital phase current values, via the second core, estimate a second output torque based on the second rotor-angle data and the second digital phase current values, and, via the third core, command de-activation of the electric machine in response to a difference between the first and second output torques exceeding a threshold.

Abstract: An optical device includes a movable section including an optical section that deflects video light in accordance with the angle of incidence of the video light incident on a light incident surface and outputs the deflected video light and a holder that supports the optical section, an actuator that rotates the movable section around a first axis, an actuator that rotates the movable section around a second axis, a drive circuit that supplies the actuator with a first drive signal and the actuator with a second drive signal, and a sensor disposed in a position different from the positions on the first and second axes detects the position of the optical section, and the drive circuit adjusts the first and second drive signals in accordance with the position of the optical section detected with the sensor.

Abstract: An electronic timepiece enables driving by appropriate drive conditions even when the load on a motor changes. The electronic timepiece includes a motor having a coil; a driver that is controlled to an on state supplying drive current to the coil, and an off state not supplying the drive current; a driver controller configured to control the driver to the on state or the off state based on a control parameter and current value through the coil; and a control parameter setter configured to maintain or change the control parameter based on the on state or the off state control state of the driver controller.

Abstract: An image forming apparatus and an image forming method are provided. The image forming apparatus includes a printing engine to form an image, a step motor to drive the printing engine, a driving circuit to provide a constant current to the step motor and sense a voltage corresponding to a magnitude of the constant current provided to the step motor, and a processor to calculate a temperature of the step motor based on the voltage sensed by the driving circuit during an excitation period of the step motor and control an operation of the image forming apparatus based on the calculated temperature.

Abstract: An apparatus for energy and data transfer, can include a first inductor and a second inductor, wherein the first inductor can be magnetically coupled to the second inductor, and a gap configured between the first inductor and second inductor, wherein the first inductor and the second inductor can transfer energy and data between a white meter and an electronic index. The white meter may be implemented as a flow meter. The electronic index can include an electronic display unit that can be attached to the white meter. The electronic display can include one or more of a display unit, a communications unit, or a combination of a display unit and the communications unit.

Abstract: An image forming apparatus according to the present disclosure includes a power supply circuit, a driving circuit, an opening/closing unit, a first switch configured to switch to a connected state and a disconnected state, at least one processor including a first mode for executing vector control for controlling the driving circuit and a second mode for controlling the driving circuit. The at least one processor is configured to determine a rotational phase using a detected current and a set control value, to control the driving circuit, to execute discriminating a type of the motor based on the detected current in the second mode, and to set the control value based on a result of the discriminating. The result based on the detected current in a state where the first switch is in the disconnected state is not used to set the control value.

Abstract: To reliably rotate a step motor while reducing power consumption, a step motor driving device includes a step motor that includes a rotor, stator, coil, driver circuit that outputs a measurement drive signal to the coil, phase detecting circuit that detects a counter-electromotive current that is generated in the coil after the output of the measurement drive signal and determines whether a phase of the rotor is a desired phase based on the detected counter-electromotive current, and a control unit that, if the phase is the desired phase, controls the step motor by a first driving method in which the drive circuit outputs a first drive signal for rotating the rotor by one step, and, if not, controls the step motor by a second driving method different from the first driving method so as to restrict the rotation of the rotor.

Abstract: An operation method and an operation device of a motor driver for driving a motor are provided. The operation method includes: establishing a hysteresis control method; and adjusting a switch frequency of a power module for operating the motor by using the hysteresis control method according to a change of rotation speed of the motor and a current switch frequency.

Abstract: Automated speed ramp control of stepper motor acceleration and deceleration using direct memory access (DMA) and core independent peripherals (CIPs) comprises a numerically controlled oscillator (NCO) controlled through direct memory access (DMA) transfers of prescale values used in combination with a clock oscillator to generate clock pulses that are a function of the clock oscillator frequency and the prescale values. This automates changing the frequency of the NCO, thereby controlling steeper motor speed, without requiring computer processing unit (CPU) overhead. The DMA module is enabled during a first number of clock pulses for step speed acceleration, disabled during a second number of clock pulses for normal operation at full step speed, and then re-enabled during a third number of clock pulses for step speed deceleration. A table in memory may store and provide a plurality of acceleration and deceleration prescale values for DMA transfers to the NCO.

Abstract: A retrofit damper system is configured for installation in existing ductwork including a duct supplying conditioned air through a register boot to a register vent. The retrofit damper system includes a damper assembly including a damper blade and a damper motor configured to drive the damper blade between a closed end position and an open end position. A control module includes a control module housing and a controller within the control module housing that is configured to regulate operation of the damper motor. The controller outputs a drive signal that causes the electric damper motor to drive the damper blade to the desired position and creates a plurality of interruptions in the drive signal while driving the damper blade. A sense circuit senses back EMF signal, and the controller estimates a blade position based at least in part on the back EMF signals.

Abstract: The present invention relates to a driving circuit and a driving method for a stepping motor, and an electronic machine using the same. A current value setting circuit generates a current setting value. A constant current chopper circuit generates a pulse modulation signal, which pulse-width modulates by having a detection value of a coil current flowing through a coil approach close to the current setting value. A logic circuit controls a bridge circuit connected to the coil of the stepping motor according to the pulse modulation signal. The current value setting circuit sets the current setting value to a predetermined full-torque setting value in a first period after rotation starts, reduces the current setting value to a predetermined second setting value less than the first setting value in the following second period, and switches to a high-efficiency mode and adjusts the current setting value by means of feedback control.

Abstract: The present invention relates to a control device and to a control method for a vehicle drive mechanism including a moving body having a movability range regulated by two stoppers, and a sensor which senses a position of the moving body. The control device of the present invention learns an output of the sensor corresponding to a contact state of a high-rigidity stopper, and limits, to a lower level, an operation variable of the actuator for moving the moving body toward a low-rigidity stopper along with an increase in an amount of change in the output of the sensor from the contact state of the high-rigidity stopper. Then, the control device learns the output of the sensor corresponding to the contact state of the low-rigidity stopper, and controls the actuator based on the output of the sensor learned at both the stopper positions.

Abstract: A novel multi-phase resolver topology and apparatus is provided for measuring a displacement of movement body more precisely and economically. In variable reluctance (VR) resolvers, N coil-poles are placed at N equally spaced positions over one turn of the stator, N being an odd number greater than or equal to 5. Each coil serves both as an excitation and a sensing coil, and all N coils are wound with the same number of turns at an identical electrical polarity. Depending on the installed rotor lobe shape, N sinusoidal or quasi-square waveform displacement signals are sensed on multi-phase resolver, and from which two-phase orthogonal displacement signals are optimally and differentially synthesized. The multi-phase resolver topology and differential synthesis method is also applied to other types of resolvers, such as wound-rotor, inductance, capacitive, and magnetic resolvers.

Abstract: A control device for a stepping motor capable of hold control that can smoothly reduce an excitation current at a rotation stopping time of the stepping motor is provided. A control device (10) for a stepping motor (20) causes an excitation current to flow in a plurality of coils to rotate a rotor. The control device (10) includes a driving circuit (40) that applies a driving voltage to the coils, and a control circuit (30) that controls the driving voltage. The control circuit (30) performs hold control to move the rotor to a predetermined stop position by changing a magnitude of the excitation current flowing in the coils so that the magnitude of the excitation current becomes close to a target current value that gradually decreases, in a hold time period at a rotation stopping time of the stepping motor (20).

Abstract: An agricultural planting implement is used to plant seed in a field. The implement includes an electrically-driven seed meter that is spaced on a toolbar of the implement. The seed meter, or other metering member, is a precision meter that is used to control the volume, spacing, and location of a seed that is delivered from a meter to the field. A seed source, such as a seed cart or hopper, is attached to the seed meters to provide an on-demand amount of seed to the meters for planting in the field.

Abstract: A novel multi-phase resolver topology and apparatus is provided for measuring a displacement of movement body more precisely and economically. In variable reluctance (VR) resolvers, N coil-poles are placed at N equally spaced positions over one turn of the stator, N being an odd number greater than or equal to 5. Each coil serves both as an excitation and a sensing coil, and all N coils are wound with the same number of turns at an identical electrical polarity. Depending on the installed rotor lobe shape, N sinusoidal or quasi-square waveform displacement signals are sensed on multi-phase resolver, and from which two-phase orthogonal displacement signals are optimally and differentially synthesized. The multi-phase resolver topology and differential synthesis method is also applied to other types of resolvers, such as wound-rotor, inductance, capacitive, and magnetic resolvers.

Abstract: An electronic timepiece can prevent overrunning when driving a motor at a high speed. The electronic timepiece has a controller that controls a driver to an on state or an off state according to the current value detected by the current detector; a polarity changer that determines driving one step of the motor ended and changes the polarity of the drive current when the on time or off time is detected to meet a specific condition; and a drive period adjuster that sets the terminal supplying the drive current to the coil to a first state if the remaining drive step count is greater than the remaining count evaluation number, and if the remaining drive step count is less than or equal to the remaining count evaluation number, sets the terminal to a second state in which the brake force applied to the rotor is greater than in the first state.

Abstract: In an inductive load control device, an energization controller controls an operation of an H-bridge circuit to switch from an energized state to a regenerative state when a load current value is equal to or greater than a first threshold value at a time after a mask time has elapsed from a start time of a reference cycle, and a short-circuit determination processor determines whether the short-circuit abnormality has occurred based on whether the load current value is equal to or greater than a second threshold value greater than the first threshold value. The short-circuit determination processor further determines whether the short-circuit abnormality has occurred based on the regenerative current value in the regenerative state when the load current value does not reach the second threshold value within the mask time.

Abstract: Provided is a drive circuit for a two-coil stepper motor, including: a rotor; a stator including first, second, and third stator magnetic-pole portions; a coil A to be magnetically coupled to the first stator magnetic-pole portion and the third stator magnetic-pole portion; a coil B to be magnetically coupled to the second stator magnetic-pole portion and the third stator magnetic-pole portion; a drive pulse generation circuit configured to output a drive pulse; a detection pulse generation circuit configured to output a detection pulse for detecting counter-electromotive currents generated in the coil A and the coil B; and a rotation detection circuit configured to receive a detection signal generated due to the detection pulse as input to determine whether or not the rotor has rotated.

Abstract: A magnetic connector assembly has a female connector with spring-loaded conductive pins slightly protruding inside a recess or cavity in the female connector's body. A corresponding male connector has a protrusion on its body with conductive pins slightly indented into the protrusion's surface. The protrusion on the male connector is sized and shaped to fit into the cavity in the female connector such that the male connector's pins engage the pins of the female connector, allowing for electrical communication across the connector assembly. Magnets on the male and female connectors secure them in a correct orientation. A unique shape ensures proper alignment of the pins and prevents the connection of incompatible devices.

Abstract: The present invention concerns a method of controlling a rotational speed of a rotor (3) of a direct current electric motor (1) comprising an inductor circuit (A, B) for rotating the rotor, which is configured to rotate continuously and is equipped with permanent magnets. The method comprises: measuring the rotational speed of the rotor; determining a time drift in the rotor rotation compared to a reference signal; defining N speed thresholds with at least one being a variable speed threshold depending on the determined time drift, the N speed thresholds defining N+1 rotational speed ranges for the rotor; determining in which one of the N+1 rotational speed ranges the determined rotational speed of the rotor is; and finally selecting an action relative to the control of the inductor circuit, based on the determined rotational speed range, for controlling the rotational speed of the rotor.

Abstract: A synchronized I/Q detection circuit is provided. A first subset of input signals and, subsequently, a second subset of input signals are provided by a first multiplexer and received by a first phase detector. Outputs of the first phase detector are receiving, by a first reset and sampling circuit. A second set of input signals are provided by a second multiplexer and received by a second phase detector, from a second multiplexer, while the first multiplexer receives the first and second subsets of input signals. The first subset of input signals has a same phase order as the second set of input signals, and the second subset of input signals has a different phase order than the second set of input signals. Outputs of the second phase detector are received by a second reset and sampling circuit. A comparator outputs a detected phase difference based on the outputs of the first and second reset and sampling circuits.

Abstract: A timepiece includes a stepping motor having a rotor and a coil, and a drive circuit that applies a first drive pulse having a stable stationary position at a rotor rotation angle of 90 degrees or less from a reference position and a second drive pulse having the stable stationary position at a rotor rotation angle of 90 degrees or more from the reference position, as a pulse for driving the rotor, to the coil. When a period during which the pulse is not applied to the coil is assumed as a waiting period, the drive circuit generates the waiting period after a first application of the second drive pulse after an application of the pulse to the coil is started and rotates the rotor by one or more turns without passing through the waiting period at at least one predetermined timing after the waiting period.

Abstract: A motor drive control device capable of reducing the occurrence of vibration in a simple circuit configuration is provided. The motor drive control device (1) includes a motor drive unit (2) that selectively energizes coils with a plurality of phases (Lu, Lv and Lw) of a motor (20) and a control circuit (4) that outputs a drive control signal (Sd) which is a PWM signal to the motor drive unit (2) and thereby controls driving of the motor (20) while switching energization phases of the coils with the plurality of phases (Lu, Lv and Lw) energized by the motor drive unit (2) in predetermined order. The control circuit (4) executes reduction control to temporarily reduce a duty ratio of the drive control signal (Sd) every time a period of 1/m (m is an integer of 2 or more) of a switching cycle of the energization phases elapses after switching the energization phases.

Abstract: Examples of the present disclosure relate to a device, method, and medium storing instructions for execution by a processor for estimating motor winding temperature. In an example, a device for estimating motor winding temperature includes a motor shaft and a motor winding. The device may include a current sense resistor to detect the current passing through a common wiring. The device may include a digital to analog converter to convert an input voltage to an analog signal for comparison to the voltage and to generate a differential voltage using the signals received from the current sense resistor and an initial voltage supplied to the motor winding. The device may include a processor to use the differential voltage and a current input value to calculate a resistance of the motor winding from comparison to a temperature conversion curve.

Abstract: Methods for controlling a voltage present at an electric fan during a startup of the fan are disclosed herein. The fan serves to generate a flow of air for cooling a device. The method includes applying an output voltage of a power supply, which serves to supply voltage to the device, to the fan; and switching on and switching off the output voltage of the power supply applied to the fan by a switch pulse-width-modulated-controlled by a control unit so that the Root Mean Square value of the current flowing through the fan is less than a startup current of the fan.

Abstract: A method and circuit for controlling or starting a U-shape single phase synchronous permanent magnetic motor (U-SPSPM motor) having a rotor and a stator and coupled to a single phase alternating current (AC) power source through a switch, including estimating back electromotive force (back-EMF) of the motor based on an observer model with inputs indicative of the measured signals, and triggering the switch to supply power to the motor based on the estimates of the back-EMF.

Abstract: A synchronized in-phase/quadrature phase (I/Q) detection circuit and a method of the same are provided. The synchronized I/Q detection circuit includes a first logic circuit; a first filter; a first reset and sampling circuit; a first multiplexer; a second logic circuit; a second filter; a second reset and sampling circuit; a signal generator; and a comparator.

Abstract: Methods of compensating for play and for initializing a position encoder in an actuation system (2) including an actuated system (8) comprising an elastic element, and an actuator (4) with a stepper motor (12) having at least one electrical phase.

Abstract: A control unit controls an electric motor based on position data on a window glass, and controls an opening-closing operation of the window glass. The control unit includes a reverse rotation detector which detects a reverse rotation operation of the window glass, a reverse rotation prevention controller which performs reverse rotation prevention processing of the electric motor when a reverse rotation is detected, and a position data correction unit which corrects position data on the window glass in an initial operation after occurrence of a reverse rotation operation. If a pulse signal associated with rotation of the electric motor is not input in an initial operation after the detection of the reverse rotation operation, the position data correction unit determines that the window glass has reached a top dead center position, stops the motor, and corrects the position data with the position data at that time as an origin position.

Abstract: A circuit includes a processor that analyzes a pulse width modulated (PWM) signal feedback from a brushless DC motor to determine a transition between a mutual inductance zero crossing condition and a Back Electro Motive Force (BEMF) zero crossing condition of the brushless DC motor. A mutual inductance controller is executed by the processor to commutate the brushless DC motor at startup of the motor when the mutual inductance zero crossing condition is detected by the processor. A BEMF controller is executed by the processor to commutate the brushless DC motor after startup of the motor when the BEMF zero crossing condition is detected by the processor.

Abstract: A customer replacement unit monitor (CRUM) unit that can be mounted in an image forming apparatus includes a decoder which receives first clock signals from the image forming apparatus and converts the first clock signals into second clock signals, a memory which stores data related with a consumable unit, and a controller which manages the memory based on data signals transmitted from the image forming apparatus and the second clock signals. The first clock signals are divided into a data section in which the data signals are transmitted and received and an idle section in which the data signals are not transmitted and received. The first clock signals have a first frequency on the data section while having a second frequency on the idle section, and the second clock signals are clock signals maintaining a high value or a low value on the idle section.

Abstract: A motor drive device includes a motor drive circuit which drives a stepping motor provided with three coils; a switching element for controlling a path through which a current for driving at least one of the coils flows; and a driving pulse generator which outputs a driving pulse to the switching element. The driving pulse generator outputs the driving pulse to the switching element so that the current for driving at least one of the coils flows through one path.

Abstract: A motor drive control device includes a PWM circuit configured to generate an excitation current for a motor, a measurement circuit configured to measure a charge duty of the excitation current, an arithmetic circuit configured to obtain a characteristic line from the change of the measured duty and calculate a predetermined division point of an excitation current waveform from the characteristic line, and a setting circuit configured to set a level of the excitation current at the division point.

Abstract: Provided is a drive circuit for a two-coil stepper motor, including: a rotor; a stator including first, second, and third stator magnetic-pole portions; a coil A to be magnetically coupled to the first stator magnetic-pole portion and the third stator magnetic-pole portion; a coil B to be magnetically coupled to the second stator magnetic-pole portion and the third stator magnetic-pole portion; a drive pulse generation circuit configured to output a drive pulse; a detection pulse generation circuit configured to output a detection pulse for detecting counter-electromotive currents generated in the coil A and the coil B; and a rotation detection circuit configured to receive a detection signal generated due to the detection pulse as input to determine whether or not the rotor has rotated.

Abstract: A blower system, including a permanent magnet motor and a wind wheel. The permanent magnet motor includes a stator assembly, a rotor assembly, and a motor controller. The rotor assembly includes a salient pole rotor including a rotor core and magnets embedded in the rotor core. The motor controller includes a microprocessor, a frequency inverter, and a sensor unit. The sensor unit inputs a phase current or phase currents, a phase voltage, and a DC bus voltage into the microprocessor. The microprocessor outputs a signal to control the frequency inverter which is connected to a winding of the stator assembly. The ratio between an air gap of the motor and the thickness of the magnets ranges from 0.03 to 0.065, and the ratio between the length of a pole arc and the length of the magnets ranges from 0.8 to 1.0.