Abstract: A method for controlling a multi-phase motor includes withholding energization of a first phase of the motor for a non-zero period when the first phase's dwell time begins. Energization of the first phase is activated upon the expiration of the non-zero period. Energization of the first phase is deactivated for the remainder of the dwell time at a deactivation time occurring before or at the expiration of the dwell time.

Abstract: A DC-motor (46) actuates a highly-reduced reduction gear of an actuating drive for a flap or valve in order to regulate a gas or liquid volume flow, particularly for heating/ventilation/climatization, or fire or room protection. Current flow in the stator coils (A, B, C) is commutated in a program-controlled manner without integrated position sensors. Algorithms enable counting rotations of rotor (54) of the DC-motor (46). Problems related to the principle of motor rotation speed at low rpm are prevented. The DC-motor (46) includes a stator (44) having three stator coils (A, B, C) which extend over 3n stator poles (52), and an annular-shaped permanent magnet rotor (54) having 2m permanent magnet segments with alternating polarity (N, S), a coaxial cup-shaped external rotor (110) and a coaxial drive shaft (108), whereby n and m are whole multiplication factor numbers (1, 2, 3, 4) and are different from each other.

Abstract: An energy converter includes magnetic coils of N phases (N is an integer of 3 or more), and a PWM drive circuit for driving the magnetic coils of N phases, wherein the magnetic coil of each phase can be independently controlled by the PWM drive circuit.

Abstract: The adapting system for a resonant drive appliance includes a circuit for measuring the back EMF induced in the stator coil of the motor following turn-off of the appliance. The frequency of the back EMF signal is determined from the zero crossings of the EMF signal. The determined frequency is then compared with a running average of previous frequency determinations, and the drive frequency of the appliance is adjusted if the difference between the compared frequencies is greater than a threshold value, e.g. 1 Hz.

Abstract: A method and an apparatus for the failsafe monitoring of an electromotive drive without additional sensors, including a drive having a three-phase control of an electric motor, detection of the current and voltage profiles of each of the three phases, as they are forwarded to the motor by drive electronics, determination of the load speed while using the detected current and voltage values, where the determination of the load speed takes place by calculating an observer model with reference to the detected current, to the detected voltage, to the frequency preset by the control and to the characteristic data of the motor and generation of a failsafe switch signal for the motor when the calculated load speed does not correspond to a preset desired speed within the framework of preset tolerances. The load torque can also be determined and monitored with reference to the observer model.

Abstract: The device is provided with an electric power conversion circuit including switching elements for converting a DC electric power to an AC electric power, a load connected to an output side of the electric power conversion circuit, means for detecting a current flowing through a DC side in the electric power conversion circuit, a voltage command value preparing means for controlling the operation of the switching elements in the electric power conversion circuit and a wire breaking detecting means. The wire breaking detection means judges a wire breaking in the load or an abnormality of any of the switching elements in the electric power conversion circuit by making use of a DC current detection value in a period when a current of maximum voltage phase or of voltage minimum phase of the electric power conversion circuit is flowing in a DC current.

Abstract: A compact field programmable gate array (FPGA)-based digital motor controller (102), a method, and a design structure are provided. The compact FPGA-based digital motor controller (102) includes a sensor interface (206) configured to receive sensor data from one or more sensors (104) and generate conditioned sensor data. The one or more sensors (104) provide position information for a DC brushless motor (108). The compact FPGA-based digital motor controller (102) also includes a commutation control (210) configured to create switching commands to control commutation for the DC brushless motor (108). The commutation control (210) generates commutation pulses from the conditioned sensor data of the sensor interface (206). The compact FPGA-based digital motor controller (102) also includes a time inverter (208) configured to receive the commutation pulses.

Abstract: An energy converter includes magnetic coils of N phases (N is an integer of 3 or more), and a PWM drive circuit for driving the magnetic coils of N phases, wherein the magnetic coil of each phase can be independently controlled by the PWM drive circuit.

Abstract: Method for determining the angular position of the rotor of a mechanically commutated DC servo motor (5), which is arranged in the transverse branch of a bridge circuit, and the armature current of which is preset by an electromechanically activated switching device (28), —with a control and analysis unit (17) which analyzes the current ripple (3) present in the armature current (2) and attributable to the mechanical commutation, characterized in that—from each switch contact (6, 7) of the switching device (28), a contact-voltage feedback signal (9, 10) is fed back to the control and analysis device (17) by means of a feedback circuit (20), and in that the control and analysis unit (17), by using the at least one contact-voltage feedback signal (9, 10), determines a contact vibration time interval (4) and performs an estimate of current ripple (3) during this contact vibration time interval (4), during which an analysis of the current ripple due to contact vibrations which are caused by a switching process of

Abstract: The invention relates to a method for positional recognition of a rotor of an electronically commutated electric machine, in particular an electric motor, in which a zero crossover of a voltage induced in a coil section of the rotor or stator is used for positional recognition. According to the invention, to determine the zero crossover the coil section is briefly powered down. A rotor/stator is used, comprising at least two coil sections, one of which has a lower inductance relative to the other one, and preferably only the coil section with the lower inductance is used for the positional recognition.

Abstract: A single controllable switch (509) drive system for regulating the speed of a two-phase switched reluctance machine (TPSRM) (700) rotor may include a speed control feedback loop (970) component that uses an established speed control signal and a signal indicative of the rotor's speed to dynamically adjust a first parameter. And a current control feedback loop (976) component that uses an established current control signal and a signal indicative of the current flowing through a stator winding (505,508) of the TPSRM to dynamically adjust a second parameter.

Abstract: The rotation angle detection device detects the rotation angle of a rotary member by employing, at the least, either a sine wave signal or a cosine wave signal that is generated as the rotary member is rotated, and employs a change per unit time in the sine wave signal or cosine wave signal to determine whether an output abnormality has occurred in the rotation angle detection device. Further, this rotation angle device is employed to detect the motor angle of an electric power steering apparatus.

Abstract: A hard disk driving circuit for reducing a maximum amount of current for driving a spindle motor, and a method of driving the spindle motor. The hard disk driving circuit include spindle motor, a spindle motor driving circuit driving the spindle motor, a control circuit controlling the spindle motor driving circuit, and a plurality of functional blocks related to driving a hard disk, and further includes a mask clock signal generator generating a mask clock signal that is inactivated for a period of time when the spindle motor is driven, by using the clock signal. At least one selected from the group consisting of the control circuit, the spindle motor driving circuit, and the plurality of functional blocks operates according to the mask clock signal.

Abstract: Under the same target voltage, a basic duty ratio depending on a target ON time is set, and prior and subsequent duty ratios before and after upper arm switching devices or lower arm switching devices are driven with the basic duty ratio are set as a basic duty ratio+? and a basic duty ratio??, respectively. Gate drive signals, having the basic duty ratio and the prior and subsequent duty ratios, are supplied to the upper arm switching devices or to the lower arm switching devices, in order to turn on the upper arm switching devices or the lower arm switching devices.

Abstract: Disclosed is a method for detecting the current position of a rotor, in particular the angle of rotation of the rotor, an electromotor and a method for detecting the speed and/or the angle of rotation of an electromotor. The speed of the electromotor is hereby implied inter alia from the number of zero crossings of a comparison signal of the armature resistances or respectively conductances determined continuously in time and the average values of the armature resistances or respectively conductances determined continuously in time.

Abstract: A motor and a control unit therefor comprise: salient rotor poles and salient stator poles, which are arranged along circumferences of phases A, B and C with an even interval therebetween; magnetic paths for passing magnetic fluxes, the paths permitting the magnetic fluxes passing through the salient rotor and stator poles of each phase to return to the rotor side; and substantially looped windings arranged between the salient stator poles of individual phases and the magnetic paths for passing magnetic fluxes, wherein currents are supplied to the windings in synchronization with the rotational position of the rotor to thereby output torque. Since the structures of the stator, the rotor and the windings are simple, productivity is enhanced, whereby high quality, small size and low cost can be realized.

Abstract: The present invention relates to a switched reluctance motor and a connection method for a sensor shutter thereof. The switched reluctance motor in accordance with the present invention includes a stator; a rotor rotating with respect to the stator centering around a rotational shaft; and a sensor shutter having a sensing part through which a light can be passed and connected to an end portion of the rotational shaft, and a stopping ring is connected to the end portion of the rotational shaft so as to prevent the sensor shutter from being separated. Accordingly, the sensor shutter can be quickly and easily connected and the length of the rotational shaft can be decreased.

Abstract: The controller determines the presence or absence of operation of the trigger switch according to an ON/OFF state of the main contact of the trigger switch and designating the rotation speed of the motor based on a signal outputted from the speed contact. The controller stops the rotation of the motor, after the trigger switch is activated and the main contact is turned ON and the motor is driven according to a signal outputted from the speed contact, when an OFF state of the main contact is detected, only in the case where a signal value outputted from the speed contact is a predetermined value or less.

Abstract: In a normal operating mode, a motor controller provides motor drive current to windings of a motor based on sensor signals to drive the windings in a normal commutation sequence, and monitors for occurrence of a motor stall condition. Upon detecting the motor stall condition in a given commutation state, then in a first driving step, the windings are momentarily driven according to an advanced commutation state, and during the first driving step, a reverse transition of the sensor signals to a state corresponding to a preceding commutation state is detected.

Abstract: A disk drive is disclosed comprising a disk, a head actuated over the disk, and a spindle motor for rotating the disk, wherein the spindle motor comprises a plurality of windings. During a spin-up operation of the disk, a sinusoidal driving signal is applied to each winding of the spindle motor for a spin-up interval, wherein during at least eighty percent of the spin-up interval the sinusoidal driving signals are applied to the windings of the spindle motor open loop.

Abstract: The invention relates to a method carried out with simple means for determining the position of the rotor in a sensorless and brushless multi-phase electric motor (1) in addition to a device particularly suitable for carrying out said method. According to said method, a phase voltage (Uv) on the clamping side on said motor phase is to be detected after clamping a first motor phase (V) from the reference potentials (UZ,M) of an intermediate circuit (7) during a detection period (TE), via which the detection period (TE) determines a peak value (Uv*) of the detected phase voltage (Uv), the peak values (Uv*) are to be compared to the comparative value (Uc), and a positon signal (SP) is to be produced when the peak value (Uv*) exceeds the comparative value (U0).

Abstract: A control circuit (120, 140) for a brushless direct current (DC) motor (160) includes a current drive circuit (140), a current loop regulator (122), and a commutation loop regulator (124, 126). The current drive circuit (140) is adapted to drive the brushless DC motor (160) in a first polarity or a second polarity selectively in response to a control signal, and senses a current through the brushless DC motor (160) to provide a current sense signal. The current loop regulator (122) varies a duty cycle of the control signal to regulate the current in response to the current sense signal, and regulates the polarity of the current based on a state of a polarity signal. The commutation loop regulator (124, 126) regulates a transition of said polarity signal in response to a comparison of a pre-commutation duty cycle value and a post-commutation duty cycle value.

Abstract: A rotor position detecting circuit includes a first position detecting circuit having a low-pass filter that shapes up phase voltage induced in a phase coil and a first comparator that compares the output voltage of the low-pass filter with a threshold level to form a first rotor position signal, and a second position detecting circuit having a second comparator that compares the phase voltage with a threshold voltage and a control unit that digitally processes the output voltage of the second comparator to form a second rotor position signal. The control unit corrects the first rotor position signal by the second rotor position signal to provide a final rotor position signal when the rotation speed of the brushless DC motor is in a measurable range.

Abstract: An apparatus for monitoring current for a motor drive including at least high-side and low-side switching transistors includes a driver circuit for driving a gate of the low-side switching transistor. First circuitry measures a drain to source voltage across the low-side switching transistor and generates a voltage output responsive thereto. Second circuitry has a first state of operation that samples the voltage output of the first circuitry when the low-side switching transistor is turned on and has a second state of operation to sample the voltage output of the first circuitry when the low-side switching transistor is turned off. The second circuitry further generates a monitored output current responsive to the sampled voltage output.

Abstract: A cleaner that can be operated at motive force of sufficient strength by using a battery voltage as well as by using a AC voltage. The cleaner uses a low-resistance-mode motor to rotate a collecting fan. The low-resistance-mode motor is driven by a motor driver. The motor driver drops a DC voltage converted from the AC voltage, depending on whether the AC voltage is received. Depending on whether the AC voltage is received, the motor driver drives the low-resistance-mode motor using one of the battery voltage and the dropped voltage.

Abstract: An apparatus and method for driving a 2-phase SRM are provided. The method may include initializing 2-phase SRM based on a detected position of a rotor by an initializing sensor at a time of an initial driving, and normally driving the 2-phase SRM based on a detected position of the rotor by a driving sensor. With this method, a sufficient amount of torque is generated when the 2-phase SRM is driven at a high speed. The apparatus may include an initializing sensor that detects each position of each phase of a 2-phase SRM, and generates an initializing sensor signal based on the detected result; a driving sensor that detects each position of each phase of the 2-phase SRM, and generates a driving sensor signal based on the detected result; and a microprocessor that initially drives the 2-phase SRM based on the initializing sensor signal at the time of an initial driving, and normally drives the 2-phase SRM based on the driving sensor signal at the time of a normal driving.

Abstract: Disclosed is an electromotive power steering for a motor vehicle, in which a special type of reluctance motor or series wound motor is used while such an electric motor is electronically commutated. In order to recognize an error condition in the electronic control device and the electric motor, adequate mechanisms are provided in the circuit arrangement (15), the electric motor being cut from the power source by means of a relay (16) or by short-circuiting the power source downstream of a safety device (17) with the aid of a thyristor (18).

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: This application describes a motor designed to operate as a reluctance machine at low speeds and as an induction machine at high speeds. The drive waveform is composed of one or more harmonics to be used to match the reluctance pattern of the stator-rotor, causing the rotor to rotate due to the reluctance effect, and one or more other harmonics to induce current in the rotor, causing the rotor to rotate due to the induction effect and the subsequent interaction of the stator and rotor magnetic fields. The two effects are generally not applied simultaneously.

Abstract: A cleaner that can have the sufficient capability of collecting pollutant particles by a battery voltage as well as a AC voltage. The cleaner uses a switched reluctance motor to rotate a collecting fan. The switched reluctance motor is driven by a motor driver in one of a PWM mode or a pulse trigger mode. The motor driver drives the switched reluctance motor using one of the battery voltage and a DC voltage converted from the AC voltage, depending on whether the AC voltage is received. The PWM mode and the trigger mode are switched depending on whether the AC voltage is received. Accordingly, the cleaner makes it possible to reduce the time taken to clean up pollutant particles using the battery voltage to the time taken to clean up the pollutant particles using the AC voltage.

Abstract: A driver for a motor in a device includes a reference generator to generate a reference value. A clock management module receives a plurality of clock signals. Each clock signal has a corresponding frequency that is different relative to the corresponding frequency of another clock signal. A clock management module selects a different clock signal of the plurality of clock signals for output from the clock management module at different times during operation of the device. A ramp generating module generates a ramp signal in accordance with the corresponding frequency associated with the selected clock signal. A first pulse width modulation module receives the reference signal and the ramp signal. The first pulse width modulation module outputs a first pulse width modulation driver signal for driving the motor based on the reference signal and the ramp signal.

Abstract: A method of controlling a brushless DC motor of the type having a stator, comprising a stator winding excitable to generate a stator magnetic field, and a rotor, arranged to rotate with respect to the stator and comprising permanently magnetized material arranged to generate a rotor magnetic field to interact with the stator magnetic field to produce rotation of the rotor. The method comprises the steps of driving current through the stator winding to generate a stator magnetic field to interact with the rotor magnetic field, detecting rotor position with respect to the stator, and cyclically commutating the stator winding current according to rotor position as the rotor rotates. Each commutation cycle includes a drive portion during which current is driven through the stator winding in one sense and at the end of which the driving of current in said sense is ceased.

Abstract: Disclosed is an apparatus and method for driving a 2-phase SRM capable of individually performing an initial driving by an initializing sensor and a normal driving by a driving sensor, and capable of controlling a rotation speed of the SRM by delaying a phase signal by a half period and then generating a pulse width modulation signal based on the period. The apparatus comprises: a driving sensor which detects a position of a rotor thus to generate a driving sensor signal based on a result of the detection; a microprocessor which generates a 1-phase signal and a 2-phase signal based on a rising time and a falling time of the driving sensor signal at the time of a normal driving; an oscillator which generates first and second pulse width modulation signals delayed by a preset time; and a multiplying unit which multiplies the 1-phase and 2-phase signals with the first and second pulse width modulation signals, and generates 1-phase and 2-phase driving signals based on a result of the multiplication.

Abstract: A plurality of detection target portions are arranged around a rotating shaft of a rotating-body, one of which causes a detector to generate a first detection signal different from a second detection signal generated from the others. A first generating unit generates a reference signal indicating a reference rotational-position of the rotation-driving source or the rotating-body before one rotation from a timing of the first detection signal. A second generating unit reads periodic variation information from a storage unit based on the reference signal, and generates a rotation-velocity correction signal for the rotation-driving source.

Abstract: A rotor position detection circuit detects a position of a rotor in a motor from a detection signal of an induced voltage generated in a stator coil. The circuit includes: a first low pass filter having a first reference potential for filtering the detection signal; a comparator for comparing an output signal from the first low pass filter with a predetermined reference voltage and for outputting a rotation position signal; and a second low pass filter having a second reference potential for filtering a virtual neutral point potential of the motor. The first reference potential is the filtered virtual neutral point potential, and the second reference potential is a ground.

Abstract: A method for measuring the rotational speed of an EC motor having a primary part including a winding, and a secondary part having magnet segments offset with respect to one another in the circumferential direction and magnetized in alternatingly opposite directions, the magnet segments having tolerances regarding their positioning and/or their dimensions, the method including rotating the secondary part with respect to the primary part and detecting the position of the magnet segments with respect to the primary part. The position measuring signal is differentiated to form a rotational speed signal. At least one correction value is determined and saved to compensate the influence of at least one of the tolerances on the speed signal. The speed signal is corrected with the aid of the correction value.

Abstract: Disclosed is a controller circuit, comprising a plurality of sense inputs, an instrumentation amplifier block having inputs coupled to the plurality of sense inputs, a filter block coupled to the instrumentation amplifier block, a sum function coupled to the filter block, and a crossing detector block coupled to the filter block and the sum function. A method of controlling motor signals is further described.

Abstract: Disclosed is an electric drive for a vehicle, which is used as a main drive or a hybrid drive. The electric motor of said drive is embodied as a special type of reluctance motor or series wound motor. The rotor of the reluctance motor and the inverse speed motor is provided with an excitation winding to which a transistor is assigned that allows the motor to be braked in a sensitive manner so as to control the field current. The braking current is fed to the source of current by switching operation of the motor during generator operation.

Abstract: Taught herein is a controller for a direct current brushless motor connected to a high voltage control system, comprising a microprocessor and an input/output interface circuit connected between the high voltage control system and the microprocessor; wherein the input/output interface circuit is a step-down circuit for transforming a high voltage control signal into a low-voltage control signal. The controller enables the high voltage control system to cooperate with motor, therefore a user is not necessary to design a new high voltage control system when replacing the conventional AC motor with the DC brushless motor, which saves time, and reduces cost.

Abstract: A servo device is provided which includes a drive source made of a brushless motor. A DC motor driving integrated circuit produces output signals and controls the output of a three-phase brushless motor driving integrated circuit to drive the brush less motor. A selection switching section detects information regarding the rotational speed of the brushless motor. The selection switching section extracts the counter electromotive voltage of the brushless motor, feeds the voltage back to the DC motor driving integrated circuit and PWM controls a drive signal output from the three-phase brushless motor driving integrated circuit. This allows the brushless motor to be easily applied to the servo device.

Abstract: Systems and methods are disclosed for detecting high-voltage levels associated with a work machine. In one embodiment a high-voltage detection system is disclosed and includes a threshold detector configured to determine a voltage level associated with an element, determine whether the voltage level associated with the element is greater than a predetermined threshold value, and provide a threshold indicator if the voltage level associated with the element is greater than the predetermined threshold value. The system also includes a controller coupled to the threshold detector via an isolation device. The controller is configured to detect the threshold indicator and provide one or more warning signals in response to the threshold indicator.

Abstract: An electrically commutated motor comprises a plurality of stator phases and a rotor. Further, sensors for detecting the control deviation of the rotor in relation to the stator phases are provided. A phase control unit controls the stator phase rotary field depending on the detected control deviation. The phase control unit comprises a single-phase controller for a single-phase mode of operation, and a multiple-phase controller for a multiple-phase mode of operation. Further, a control deviation evaluation element is provided which evaluates the magnitude of the control deviation, and selects, depending on the evaluation result, the single-phase mode of operation or the multiple-phase mode of operation.

Abstract: A self-excited, switched reluctance generator obtains excitation energy from a capacitor bank via an excitation bus during normal operation. During a short-circuit or load fault, one or more phases of the generator provide power to the excitation bus while the remaining phases send current to a faulted positive bus. The system does not require an external battery or power source for excitation energy. The system is capable of resuming normal operation after the load bus fault.

Abstract: This application describes a motor designed to operate as a reluctance machine at low speeds and as an induction machine at high speeds. The drive waveform is composed of one or more harmonics to be used to match the reluctance pattern of the stator-rotor, causing the rotor to rotate due to the reluctance effect, and one or more other harmonics to induce current in the rotor, causing the rotor to rotate due to the induction effect and the subsequent interaction of the stator and rotor magnetic fields. The two effects are generally not applied simultaneously.

Abstract: A driving apparatus and a driving method for a single phase motor utilizes a driving transistor unit, and an auxiliary driving transistor unit to provide two driving currents with the same direction as the single phase coil. Next, a control unit is used to control the conducting and shutting down of the driving transistor unit and the auxiliary driving transistor unit according to the location of the rotating device of the single phase motor. Thereby, the driving current on the single phase coil recirculates to reduce the vibration and noise of the single phase motor, and prevent the problem of the single phase motor not turning on.

Abstract: Apparatus for driving a three-phase compressor assembly from a single-phase electrical power supply having first and second power lines, said three-phase compressor assembly comprising a compressor having a rotatable shaft, an electrical motor having a rotatable shaft coupled to the rotatable shaft of the compressor, the electrical motor having at least first, second and third motor windings and having at least first, second and third terminals connected to the first, second and third windings, means adapted to connect the first and second power lines of the single-phase power supply to the first and second terminals and a torque augmentation circuit for injecting current into the third terminal and including a capacitor and an electrical component in series with the capacitor, said electrical component having resistive characteristics and having means for essentially interrupting the current being injected into the third terminal.

Abstract: An apparatus for self-generating a driving force employs an electromotive force generated on a coil by electromagnetic induction, in combination with a mechanical driving device to drive a rotating shaft of the device, such that the rotating shaft can rotate without any external power after an initial activation. The apparatus comprises a mechanical driving device, at least two coils, wherein the mechanical driving device includes arms in attachment with magnetic bodies, thereby enabling an opposite electromotive force to be generated based on an electromagnetic induction to apply a force on the magnetic bodies for a rotation of the shaft.

Abstract: A start-up circuit which decreases a start-up current and stabilizes running of a DC fan. The start-up circuit includes a digital-analog converter for convert a digital control signal from a control chip to an analog control signal, a voltage sampling device connected to an output terminal of the digital-analog converter, a comparator, a switching device for controlling start-up of the DC fan, and a feedback device adjusting current passing through the switching device. The comparator includes two input terminals and an output terminal. One input terminal is connected to an output terminal of the voltage sampling device. The switching device is connected to the output terminal of the comparator. An output signal of the switching device is inputted to the other input terminal of the comparator via the feedback device.

Abstract: A method for determining an initial position of a rotor of a polyphase motor is described. The method comprises determining current change values from a plurality of phases of the motor during saturation of the motor relating to the initial position of the rotor; identifying a set of modelled current change values according to a modelled behaviour of the motor, in which the modelled current change values represents modelled positions of the rotor under the modelled behaviour; and comparing the current change values to the set of modelled current change values to identify the initial rotor position from the modelled positions. A system implementing the method is also described.

Abstract: A drive control device for a brushless motor having a rotor and a plurality of coils with different phases can be included in an image reading apparatus or an image forming apparatus. The drive control device may include a detection target configured to rotate in synchronization with rotation of the rotor and having formed thereon a pattern representing modulation information, a detector configured to read the pattern and to output modulated output signals, a demodulator configured to demodulate the modulated output signals and to obtain demodulated information, and a controller configured to control rotation of the rotor on the basis of at least the demodulated information obtained by the demodulator.