Abstract: A control apparatus is for controlling an AC rotary machine which includes a first and second stator elements and a rotor, in which the first stator element can be turned, or offset, in a circumferential direction relative to the second stator element. The control apparatus includes an actuator for adjusting a voltage induced in a stator coil due to rotation of the rotor by driving the first stator element, a magnetic flux command calculator for calculating a desired magnetic flux amplitude command based on rotating speed of the AC rotary machine, a magnetic flux estimator for estimating magnetic flux amplitude of the AC rotary machine, a speed command calculator for calculating an actuator speed command to be given to the actuator so that the estimated magnetic flux amplitude follows the magnetic flux amplitude command, and an actuator controller for controlling the actuator according to the actuator speed command.

Abstract: This invention provides an inverter device that can detect a step-out state of an AC motor by a simple process without depending on a rotation speed of the AC motor and also surely hold an abnormal state in the step-out state of the AC motor. The inverter device 1 includes a torque current control unit 6 for controlling a torque current direction voltage so that a given torque current command value coincides with a torque current detection value, and a V/f conversion unit 7 for calculating an induced voltage command of the AC motor 2 based on a given output frequency command. The inverter device further includes a step-out detection unit 10 for detecting a step-out state of the AC motor 2 based on the torque current direction voltage and the induced voltage command.

Abstract: An integrated circuit for controlling a DC motor is disclosed. The integrated circuit includes at least one digital position and speed circuit (DPS) for providing measurements of speed, position, and direction of the motor, the DPS being in signal communication with the motor for receiving a pair of signals having a quadrature relationship; and at least one programmable gain amplifier (PGA) electrically coupled to the motor, the PGA being configured to receive a feedback signal indicative of current flowing through the motor and to apply a second signal to the motor for adjusting the speed of the motor; and at least two analog-to-digital converters (A/D), one A/D being used to quantize the output of the PGA for an off-chip processor; and another A/D to provide motor reference position from an analog sensor, such as a potentiometer; and at least two digital-to-analog converters (D/A), one D/A used to set the motor voltage; and another D/A used to set the motor current limit.

Abstract: In a system in which current is detected in an inexpensive manner or in a system in which a position detector is omitted, the present invention provides a high-efficiency vector controller for a permanent magnet motor that can minimize current at the same torque even when there is setting error (R?R*) in resistance. Even when a current value commanded for the d-axis is set to zero, a virtual inductance value calculated from a detected q-axis current value is used for output voltage value calculation and phase error estimation calculation; so even if there is setting error (R?R*) in resistance, current can be minimized at the same torque and thereby the present invention can provide a high-efficiency vector controller for a permanent magnet motor.

Abstract: A neutron chopper according to the present invention includes a housing which internally forms a sealed space, the housing having window portions through which neutrons pass, a fixed shaft which is fixed inside the housing, a rotor which is rotatably supported by the fixed shaft, the rotor provided with a blocking portion which can block neutrons passing through the housing, and a motor which is provided inside the housing for rotating the rotor of the neutron chopper, where a stator of the motor is fixed to the fixed shaft, and a rotor of the motor receives a rotating force from the stator around the fixed shaft, and is fixed to the rotor of the neutron chopper. The neutron chopper is formed with small size, and neutron guides are easily disposed closely, consequently vacuum leak is hardly occurred in the neutron chopper.

Abstract: Let an axis parallel to a magnetic flux produced by a permanent magnet provided on a rotor of a motor be called a d-axis, let an axis leading the d-axis by an electrical angle of 90 degrees be called a q-axis, and let control axes corresponding to the d-axis and the q-axis be called a ?-axis and a ?-axis, respectively. Then, a motor control device performs vector control of the motor with the ?-axis and the ?-axis made different from the d-axis and the q-axis, respectively, and with a motor current passing through the motor broken down into a ?-axis current on the ?-axis and a ?-axis current on the ?-axis.

Abstract: Alternating current electric induction motor, in particular a motor (12-22) which is fed by a frequency variator, comprising a casing (4) which supports a rotor (9) by means of roller bearings (8) and which supports a stator (13) with a coaxial ring-shaped core (16) made of a magnetic material, characterized in that the stator (13) is provided with an auxiliary closed loop toroidal winding (20).

Abstract: In a driving system for an inverter that uses a diode rectifying circuit to convert a single-phase or three-phase AC voltage to a desired DC voltage and drives a permanent magnet motor, a DC-voltage pulsating frequency is estimated from a pulsating frequency setting calculated from the power supply frequency of an AC voltage and the detected current values of the inverter, and the resulting estimated pulsating frequency value and detected current values are used to correct the output voltage of the inverter.

Abstract: A multiphase current supplying circuit includes a converter, an intervening circuit, an inverter, a control circuit and a lightning arrester. A power supply system is connected to the converter with the lightning arrester interposed therebetween, and the ac voltage is rectified. The intervening circuit includes a capacitor and a bypass connected in parallel thereto. In the bypass, a diode, a resistor and a capacitor are connected in series, and the direction from an anode to a cathode of the diode corresponds to the direction from a high potential side to a low potential side of the smoothing capacitor.

Abstract: A drive control assembly for a motor including a variable frequency drive module for providing variable speed control for the motor, a bypass module for providing bypass control for the motor, and a switch for switching control for the motor between the variable frequency drive module and the bypass module. The bypass module can provide control for the motor even when the variable frequency drive module is removed from the drive control assembly.

Abstract: The present invention relates a motor controller and a motor control method of controlling a motor having a stator coil and a rotator.

Abstract: In a power converter including an inverter configured to convert a direct current voltage into an alternating current voltage by controlling switching devices to be turned ON or OFF based on a control signal and to output the alternating current voltage to a load, a carrier wave frequency is changed. A command value is compensated in accordance with the changing carrier wave frequency. The control signal results from a comparison of the carrier wave with a compensated command value. As a result of the compensation, output fluctuations caused by an error voltage between the command value and an output voltage to the load can be suppressed.

Abstract: A method for sensorless estimation of rotor speed and position of a permanent magnet synchronous machine, when the permanent magnet synchronous machine is fed with a frequency converter, the method comprising the steps of forming a stator voltage reference for the permanent magnet synchronous machine, injecting a high frequency signal (uc) into the stator voltage reference, measuring a DC-link current (idc) of the frequency converter when the permanent magnet synchronous machine (4) is fed with a voltage (us,ref) corresponding to a sum of the stator voltage reference and the injected signal, calculating a stator current estimate (îs), calculating a current error (?s) as a difference between the stator current estimate and the measured DC-link current, and estimating a rotor speed ({circumflex over (?)}m) and position ({circumflex over (?)}m) of the permanent synchronous machine based on the current error.

Abstract: Apparatus, systems, and methods are provided for reducing voltage source inverter losses. One apparatus includes a sensor couplable to the motor and configured to sense an operating frequency of the motor and an amount of torque produced by the motor. The apparatus also includes a controller coupled to the sensor, the controller configured to determine a zero vector modulation (ZVM) based on the sensed frequency and torque. A system includes means for sensing a threshold output frequency of the motor and means for sensing a threshold torque of the motor. The system also includes means for determining a ZVM for the inverter based on the sensed threshold frequency and threshold torque. One method includes sensing that a motor is operating below a threshold frequency and is producing torque above a threshold torque amount. The method also includes determining a ZVM for the inverter based on the sensed frequency and torque.

Abstract: A method and apparatus for a pump control system. One or more embodiments of the invention include a pump controller that can perform a self-calibrating procedure, can provide precise motor speed control, can provide a limp mode before shutting down the motor when system parameters are exceeded and/or fault conditions occur, can detect fault conditions, and can store fault conditions for later retrieval.

Abstract: A power converter and power conversion method wherein operation of a switching element is controlled by the frequency of a carrier wave where the frequency is varied such that the same frequency of the carrier wave is not repeated during a single modulation period.

Abstract: The vector control device includes: secondary magnetic flux command computing means (40) for computing a secondary magnetic flux command to an induction motor (6) by taking a maximum voltage that an inverter (4) can generate into account on a basis of a torque command from an external, a DC voltage to be inputted into the inverter, and an inverter angular frequency, which is an angular frequency of an AC voltage to be outputted from the inverter; q-axis/d-axis current command generating means (8 and 9) for generating a q-axis current command and a d-axis current command on a d-q axes rotating coordinate system in reference to a secondary magnetic flux of the induction motor (6) on a basis of the torque command and the secondary magnetic flux command; output voltage computing means (voltage non-interference computation portion 14, adder 17, and adder 18) for computing an output voltage that the inverter (4) is to output on a basis of the q-axis current command, the d-axis current command, and a circuit constan

Abstract: Method and system are provided for controlling an alternating current (AC) motor via an inverter. The method includes selecting a pulse sequencing method based on a modulation index of the inverter, and providing a voltage to the AC motor based on the pulse sequencing method. The system includes an inverter having a modulation index (Mi) and a controller coupled to the inverter. The controller selects a pulse sequencing method based on Mi and produces a signal based on the pulse sequencing method. The inverter includes a switch network producing a voltage in response to the signal, and the voltage drives the AC motor.

Abstract: Current command values are used instead of detected current values to estimate axis error by calculation. An axis error command value is generated according to a speed command value, and a difference between the generated axis error command value and the estimated axis error value is used to control an estimated frequency value.

Abstract: A motor control device that controls a permanent-magnet synchronous motor has: a magnetic flux controller that derives, as a specified excitation current value, a specified current value corresponding to a d-axis component of a current passing through an armature winding; and a current controller that controls, based on the specified excitation current value, the current passing through the armature winding. The magnetic flux controller makes the specified excitation current value vary periodically, based on an estimated or detected rotor position, in a current range in which the magnetic flux produced by the permanent magnet is weakened, and changes the specified excitation current value according to a rotation speed of the rotor.

Abstract: Let the rotating axis whose direction coincides with the direction of the current vector that achieves maximum torque control be called the qm-axis, and the rotating axis perpendicular to the qm-axis be called the dm-axis. A motor control device switches its operation between low-speed sensorless control and high-speed sensorless control according to the rotation speed of the rotor. In low-speed sensorless control, the magnetic salient pole of the motor is exploited, and the d-q axes are estimated by, for example, injection of a high-frequency rotating voltage. In high-speed sensorless control, the dm-qm axes are estimated based on, for example, the induction voltage produced by the rotation of the rotor. During high-speed sensorless control, the ?(dm)-axis current is kept at zero irrespective of the ?(qm)-axis current.

Abstract: Disclosed is a system for realizing rotor variable frequency speed control asynchronously and simultaneously by driving multiple motors via one inverter, which consists of a motor group, a rectifier group, a chopper group, an isolator group, an amperite group, a power capacitor group, a full bridge or a half bridge, a speed feedback voltage detector group and a current feedback voltage detector group. By employing inversion control theory, the voltage outputs by a full-bridge inverter or a half-bridge inverter is taken as an additional inverse electromotive force of each functional motor according to the rated power of the motor, and each motor is made to operate asynchronously and simultaneously by the work of each chopper, thereby the operations of a crane, lifting, luffing, revolving and walking, can be realized.

Abstract: Methods and systems are provided for aligning a resolver in an electric motor system. The method includes commanding a d-axis current command and a speed command, operating an electric motor without a load in response to the d-axis current command and the speed command, determining a rotor speed in response to the speed command, and determining an offset of the resolver based on the speed command and the rotor speed when the rotor speed has substantially stabilized.

Abstract: A system and method for precharging a harmonic filter connected to a power supply line to receive AC power and deliver the AC power to the motor drive unit includes a control circuit. The control circuit is configured to monitor an operational state of the motor drive unit or the power supply line, and generate a first control signal upon a predetermined change in the operational state and a second control signal delayed from the first control signal. The system also includes a charging circuit having a first switch configured to actuate in response to the first control signal to provide a reduced power to at least a portion of the harmonic filter and a second switch configured to actuate in response to the second control signal to provide a non-reduced power to the at least a portion of the harmonic filter.

Abstract: The invention relates to a method for determining the chance of a disturbance-free operation of a frequency converter (2) connected to a feeding network (18). According to the invention, during the operation of said frequency converter (2), an intermediate circuit voltage (UZK) is continuously measured and a network-side intermediate circuit current (iZKmains) is continuously determined; these measuring quantities are compared with pre-determined operating values of the frequency converter (2), and quantities which are higher or lower than said values are respectively stored; and the frequency (Hij) of said higher and lower measuring quantities is determined and converted into a characteristic number for the quality of the feeding network (18). As said characteristic number decreases, the chance of a disturbance-free operation of the frequency converter (2) increases.

Abstract: A stepping motor controller includes: a pulse frequency adjustment circuit that receives a command pulse having a first frequency from an external controller that outputs the command pulse in accordance with an interrupt process performed periodically by the external controller, and generates an alternative command pulse having a second frequency that is lower than the first frequency; and a motor driving circuit that receives the command pulse through the pulse frequency adjustment circuit, and controls a stepping motor to rotate on the basis of the command pulse. The pulse frequency adjustment circuit outputs the alternative command pulse to the motor driving circuit instead of the command pulse received from the external controller, when the first frequency exceeds a predetermined level.

Abstract: A refrigerant system (10, 100, 200) is provided with a power control system (30, 130, 230). The power control system adjusts the speed of the motors driving the refrigerant system components such as a compressor, a fan or a pump via a variable speed device (75, 175, 275) or bypasses the variable speed device (75, 175, 275) for normal operating speeds. A single power control system may be provided for the entire refrigerant system or each component may be independently controlled.

Abstract: Let the rotating axis whose direction coincides with the direction of the current vector that achieves maximum torque control be called the qm-axis, and the rotating axis perpendicular to the qm-axis be called the dm-axis. A motor control device switches its operation between low-speed sensorless control and high-speed sensorless control according to the rotation speed of the rotor. In low-speed sensorless control, the magnetic salient pole of the motor is exploited, and the d-q axes are estimated by, for example, injection of a high-frequency rotating voltage. In high-speed sensorless control, the dm-qm axes are estimated based on, for example, the induction voltage produced by the rotation of the rotor. During high-speed sensorless control, the ?(dm)-axis current is kept at zero irrespective of the ?(qm)-axis current.

Abstract: A speed control method of an elevator-purpose comprising previously calculating an elevating distance in such a case that the elevator passenger car is decelerated from a reference frequency up to a leveling frequency in a constant deceleration speed, when the induction motor is stopped. The elevator passenger car is driven in a constant speed at an intermediate frequency so that the previously calculated distance becomes equal to an elevating distance when the elevator passenger car is decelerated at the constant deceleration speed from an arbitrary frequency up to the leveling frequency so as to adjust the elevating distance. The elevator passenger car is automatically decelerated at the constant deceleration speed up to the leveling frequency.

Abstract: A system and method for controlling a permanent magnet motor are disclosed. Briefly described, one embodiment receives a torque command and a flux command; receives information corresponding to a direct current (DC) bus voltage and a motor speed; computationally determines feedforward direct-axis current information and feedforward quadrature-axis current information from a plurality of parameters associated with the permanent magnet motor; determines a current signal (idq*) based upon at least the requested torque command, the flux command, the DC bus voltage, the motor speed, the feedforward direct-axis current information, and the feedforward quadrature-axis current information; and controls a power inverter that converts DC power into alternating current (AC) power that is supplied to the permanent magnet motor, such that the permanent magnet motor is operated in accordance with the determined idq*.

Abstract: Systems and methods for controlling a rotating electromagnetic machine. The rotating machine, such as a permanent magnet motor or hybrid switched reluctance motor, includes a stator having a plurality of phase windings and a rotor that rotates relative to the stator. A drive is connected to the phase windings for energizing the windings. A controller outputs a control signal to the drive in response to an input demand such as a demanded speed or torque. Control methods (which can be implemented separately or in combination) include varying the gain of an estimator as a function of a demanded or estimated speed to position control system poles at desired locations, de-coupling control system currents to achieve a constant torque with motor speed, compensating flux estimates of the estimator for saturation operation of the stator, estimating rotor position using averages of sample values of energization feedback, and calculating a trim adjusted speed error from a plurality of speed estimates.

Abstract: A controller for a motor carries out field weakening control by using a simple construction to change the phase difference between two rotors, which are disposed around a rotating shaft, without depending on the number of revolutions of a motor. The controller for a motor includes a field weakening current calculator for calculating a field weakening current command value on the basis of the radius of a target voltage circle, a d-axis voltage command value, and a q-axis voltage command value, a rotor phase difference command value determiner for determining a command value of a rotor phase difference on the basis of the field weakening current command value, and a current command value determiner for determining a d-axis current command value and a q-axis current command value on the basis of the rotor phase difference command value and a torque command value.

Abstract: Driving of a pulse motor is controlled in such a manner that a rotating body driven by the pulse motor rotates at a uniform angular velocity. Angular displacement of the rotating body is detected, a difference between a detection value of the angular displacement and a target value of angular displacement set in advance is calculated, and a drive pulse frequency of a drive pulse signal to be used for driving the pulse motor is calculated based on the difference and a reference drive pulse frequency. Whether the difference is added to the reference drive pulse can be selected.

Abstract: The present invention relates to a control method for a synchronous electric motor with permanent-magnet rotor, particularly for fluid circulation pumps in conditioning systems and/or household appliances, wherein the application of predetermined voltage values to each of the windings (L1, L2) of the motor is provided, by means of a converter control circuit (10). The method provides a continuous measure of the amplitude of the bus (Vr) ripple and a comparison with a reference value, for example with respect to an average bus voltage level. According to the comparison result the motor is driven by means of a variation of the winding voltage having an sinusoidal wave form.

Abstract: The present invention employed a motor control device including: current sensors which detect currents in each phase of a three-phase motor; a coordinate conversion device which computes a d-axis actual current and a q-axis actual current in dq-coordinates from phase currents of three phases based on detection values of the current sensors; a voltage instruction computation device which computes a d-axis voltage instruction and a q-axis voltage instruction based on a deviation between a d-axis current instruction and the d-axis actual current and on a deviation between a q-axis current instruction and the q-axis actual current; a target phase current computation device which computes target phase currents for each phase from the d-axis current instruction and the q-axis current instruction; and a current difference computation device which computes, for each phase, a current difference between the phase current and the target phase current.

Abstract: A controller of a permanent magnet type rotary motor of the present invention includes: a current difference calculator decomposing a primary voltage difference which is a difference between a primary voltage of the permanent magnet type rotary motor and a maximum voltage corresponding to a source voltage, into a field-axis voltage difference component and a torque-axis voltage difference component in the rotatory magnetic flux coordinate by the use of a phase angle of the primary voltage, and calculating a field-axis current difference component and a torque-axis current difference component in the rotatory magnetic flux coordinate by the use of the voltage difference component, a field-axis inductance, and a torque-axis inductance; and a target current corrector correcting a field-axis target current and a torque-axis target current in the rotatory magnetic flux coordinate so that current difference components are zero.

Abstract: A control circuit and a control method of controlling a rotation frequency of a spindle in an optical disc drive, the control circuit comprising: a spindle controller, electrically coupled to the spindle, for driving the spindle to rotate an optical disc according to a rotation control signal; a detector, electrically coupled to the spindle controller, for detecting the rotation frequency and for generating detecting signals; a frequency-adjusting module, electrically coupled to the detector, for adjusting at least one of the detecting signals to reduce a rotation frequency difference between detecting signals; a signal selector, electrically coupled to the frequency-adjusting module, for receiving output signals generated from the frequency-adjusting module and then outputting the rotation control signal.

Abstract: A controller for a brushless motor determines difference between target currents and detected currents in a dq coordinate system and determines a target voltage applied to an armature winding based on a feedback calculation, such as PI (Proportional Integral) calculation, P (Proportional) calculation, or PID (Proportional Integral Derivative) calculation, to decrease the differences.

Abstract: A method and a system in connection with a speed and position sensorless permanent magnet synchronous machine equipped with an output filter and driven by an inverter, which method comprises the steps of forming a speed-adaptive full-order observer based on the dynamic model of the combination of the permanent magnet synchronous machine (PMSM) and the output filter, measuring the inverter output current (iA), estimating inverter output current (îA), determining the estimate for the electrical angular speed ({circumflex over (?)}m) using the estimated and measured inverter output currents (îA, iA) in an adaptation law, injecting a voltage signal (uc) into the inverter voltage reference (uA,ref 0) to obtain a modified voltage reference (uA,ref), detecting an error signal (?) from the measured inverter output current (iA), and calculating the speed correction term (??) used in the adaptation of the observer from the error signal (?).

Abstract: A vector control apparatus for a permanent magnet motor operated in the region of weak magnet field, wherein when the output voltages of the power converter saturate, the phase error command value represented by the difference between the angular position of the reference axis for control and the angular position of the motor magnetic flux axis is generated on the basis of the difference between the q-axis current command value and the detected value of the q-axis current, and the command values for the output voltages of the power converter are corrected by using the phase error command value, whereby a highly responsive torque control with high precision can be achieved.

Abstract: A motor control unit including a rotational position detector detecting a rotational position of a brushless DC motor; a current detector detecting a current of the brushless DC motor; a coordinate transformer executing rotational coordinate transformation of the current by a control phase angle and obtaining a d-axis current and a q-axis current; a current controller generating a command d-axis voltage based on a d-axis current error, and generating a command q-axis voltage based on a q-axis current error; a coordinate transformer generating a three-phase command voltage by the control phase angle; a conductive signal generator; and a position controller that, when executing a positioning operation, maintains the command d-axis current at a constant value and the command q-axis current at zero, and that controls the control phase angle based on a difference between a target stop rotational position and a rotational position detected by the rotational position detector.

Abstract: The invention proposes a system for driving a compressor, comprising an induction motor (2) for driving the compressor (3), said induction motor including a squirrel cage rotor, and a controller (1) for controlling the induction motor, said controller comprising a memory for storing drive patterns for driving the induction motor, a first frequency generation means for generating a field frequency based on a field command and/or a second field generation means for generating a voltage frequency based on a voltage command, wherein a drive pattern in extracted from the memory based on the generated frequency or frequencies. Alternatively, the invention proposes a system for driving a compressor, comprising an induction motor (2) for driving the compressor (3), said induction motor including a squirrel cage rotor, and a controller (1) for controlling the induction motor, wherein the controller is adapted to distinguish between a steady state and a transient state of the induction motor.

Abstract: An object of the present invention is to provide a driver for an induction motor which performs an operation at an acceleration suitable for the magnitude of a load and is excellent in efficiency, without an acceleration failure. The driver for an induction motor includes a slip frequency estimate value arithmetic operation section 15 for arithmetically operating a slip frequency ?s^ of an induction motor 12, and a maximum torque generation slip arithmetic operation section 16 for arithmetically operating a slip frequency ?smax at which a maximum torque is generated. When the slip frequency ?s^ exceeds a predetermined value ?smaxTH (=0.9 ?smax, etc.) corresponding to the slip frequency ?smax at which the maximum torque is generated, a speed change rate arithmetic operation section 17 and a speed change rate correcting section 18 reduce a rate of increase in a speed command ?r*.

Abstract: A map holding unit holds, in the form of a map, a voltage control amount of the q axis in a case where no demagnetization of a permanent magnet motor occurs. Based on a motor revolution number, namely the number of revolutions of the motor provided from a revolution number detection unit, a demagnetized state calculation unit calculates a rotational angular velocity. Then, based on the voltage control amount from the map holding unit, a voltage control amount to be controlled that is provided from a PI control unit and the rotational angular velocity, the demagnetized state calculation unit calculates an amount of demagnetization and outputs, if the amount of demagnetization is greater than a predetermined value, an operation signal for controlling the operation of the permanent magnet motor.

Abstract: An inverter circuit includes a bridge circuit constituted of a plurality of pairs of a high-side switching element and a low-side switching element, a command signal processing section, a pulse generating section for generating pulse signals to control the inverter bridge circuit according to the command signal to have a dead time to prevent short circuiting of the dc power source and a command signal compensation section. The compensation section modifies the command signal according to a current voltage level of the dc power source to control the dead zone, thereby preventing deformation of ac output power of the bridge circuit.

Abstract: A vector controller for a permanent magnet synchronous motor uses current command values and detected currents of the d-axis and q-axis, a calculated frequency, and motor constant settings to control the output voltage of a power converter; the motor constants are identified by use of active or reactive power obtained from the output voltage and detected current of the power converter, the calculated frequency, and the detected current immediately before or during an actual operation.

Abstract: A system is provided for controlling an electric machine. The system has a power source configured to supply electric energy to the electric machine. In addition, the system has an inverter operationally connected to the power source and the electric machine and configured to increase or decrease a rotor flux component of a voltage applied to the electric machine, while maintaining a torque component at an essentially constant level. The system further has a control device configured to determine at least one parameter of the electric machine and operate the inverter in either a first or a second mode in response to the at least one determined parameter.

Abstract: In a motor control device according to the invention, upon velocity control of a motor, a superimposed signal generating unit 9 outputs a superimposed signal idh of a repetitive waveform, such as a triangular wave or a sine wave. A d-axis current command generating unit 10 adds the superimposed signal idh generated by the superimposed signal generating unit 9d to a d-axis current command idc*0 and outputs a d-axis current command idc*. An axial misalignment detecting unit 11 (11a, 11b, 11c, and 11d) receives the d-axis current command idc* and a q-axis current command iqc* and outputs an axial misalignment angle estimation value ??^. An axial misalignment correction unit 12 receives the axial misalignment angle estimation value ??^ and an actual detected position ?m and outputs a position after correction ?m?. Therefore, detection and correction can be performed in real time through calculation at a given timing during a normal operation.

Abstract: When a torque command value from an external ECU is within a predetermined variation width, a control unit generates a signal and outputs the signal to a voltage command calculation unit so that electrostatic energy stored in a capacitor is kept at a predetermined threshold value or larger. Based on the signal, the voltage command calculation unit determines a target voltage of a voltage step-up converter that corresponds to a terminal-to-terminal voltage of the capacitor. In contrast, when the torque command value is out of the predetermined variation width, the control unit determines electric power to be supplied from a DC power supply to an inverter for allowing electric power to be supplied predominantly from the capacitor rather than from the DC power supply and outputs a signal. Based on this signal, the voltage command calculation unit determines the target voltage.

Abstract: A frequency converter for outputting a power to drive a motor, having: an inverter unit for inverting a d.c. power to an a.c. power; a control unit for controlling the inverter unit; and a housing for supporting at least the inverter unit and control unit, wherein a rise time change unit is provided in the housing, the rise time change unit changes a rise time of a waveform of a voltage output from the inverter unit.