Abstract: A device for detecting an arc fault in a polyphase electrical installation comprises: a high-frequency measuring system coupled to at least two electrical phase lines of the installation, said measuring system being configured to extract a first signal representative of high-frequency components of electrical currents flowing through said phase lines; a plurality of low-frequency measuring systems, each coupled to one electrical phase line of the installation, each being configured to acquire a second signal representative of the alternating line current flowing through the corresponding phase line; and a data-processing module programmed to detect an arc fault on the basis of the second signals and of the first signal.

Abstract: A control apparatus that controls a stepping motor, comprises a determination unit configured to determine a current value to be applied to the stepping motor by looking up a first driving table, which is to be looked up when driving is to be performed in a first driving direction, and a second driving table, which is to be looked up when driving is to be performed in a second driving direction in reverse of the first driving direction. The determination unit includes an interpolation calculation unit configured to calculate the current value by interpolation calculation that looks up both the first driving table and the second driving table, in a case in which driving is to be performed in a driving direction different from a driving direction of a preceding driving operation.

Abstract: A distributed energy system, an energy intelligent terminal, and a control method thereof are disclosed. It determines an error between the sum of initial random external input power that can be assumed by each of all the energy intelligent terminals and target power, updates the alternative operation mode for each energy intelligent terminal in an iterative manner when the error satisfies an iteration start condition until an iteration exit condition being satisfied, and determines the alternative operation mode for each energy intelligent terminal in the final iteration period as the operation mode for next duty cycle so as to regulate operation mode of the distributed energy system in real time according to the target power and energy consumption power of load to which each energy intelligent terminal corresponds. The distributed energy system has ad hoc network capability with the characteristics of fast deployment and plug and play terminals.

Abstract: A method for operating an electronically commutated servo motor includes activating the servo motor by a voltage space vector generated in accordance with a commutation pattern on the basis of a predefined torque and a rotor position of a rotor of the servo motor in accordance with an optimization target. The method further includes predefining an activation range that indicates a range of permissible voltage space vectors. The servo motor is activated in such a way that only voltage space vectors within the activation range are used.

Abstract: An animal handling system for use in a magnetic resonance device (MRD) device, including: a first elongated enclosure having a proximal end, a distal open end and a first geometry, and a second elongated enclosure having a proximal end, a distal open end and a second geometry. The first geometry comprises a first cross-sectional area that is larger than a second cross-sectional area of the second geometry. The first elongated enclosure is inserted into a first input port of the MRD device and the second elongated enclosure is inserted in a second input port of the MRD device diametrically opposite to first input port. The first elongated enclosure and the second elongated enclosure are inserted into the respective input ports, the second elongated enclosure slides into the first elongated enclosure through the open distal end of the first elongated enclosure.

Abstract: An estimate of the initial position of a rotor is made by monitoring sensed motor current signals which are amplitude and phase modulated with the rotor flux position in response to a high frequency voltage signal injection. The motor current signals are envelope detected to determine zero crossing points. Samples are taken of the motor current signals at positive and negative offsets from the zero crossing point, with the samples processed to identify a direction of the rotor flux axis. Further samples of at least one motor current signal are taken with respect to a certain phase reference, and the samples compared to resolve a polarity of the rotor flux axis which is indicative of the angular position of the rotor.

Abstract: A method for estimating a torque of a three-phase motor for a vehicle includes measuring a respective current strength in at least two of three phase lines, wherein the three-phase motor is supplied with power by a converter, and wherein the three phase lines lead from the converter to the three-phase motor of the vehicle, measuring a respective voltage at each of the three phase lines, determining a rotating field frequency as a function of the measured current strengths or the measured voltages; and determining an estimated value for the torque as a function of the measured current strengths, the measured voltages and the determined rotating field frequency.

Abstract: A power-saving driving device is provided for a same load pattern device 23 that is driven by a motor 21 receiving electric power from an inverter 19 and repeatedly operated in a same load pattern. The power-saving driving device includes: an electric power amount calculator 81 that calculates an electric power amount W received by the inverter in the same load pattern; and a parameter selection and command device 83 that makes a parameter of the inverter change to a plurality of values, compares the received electric power amounts corresponding to the values of the parameter, selects the parameter value minimizing the received electric power amount and issues the selected value as a command to the inverter.

Abstract: An electrical system assembly of an electric automobile includes an energy system, a power system, and an instrument system. The energy system includes a battery module and a management module for managing the battery module; the power system includes a motor and a controller; the battery module includes a number of storage batteries connected in series and a solar panel for charging the storage batteries; and the storage batteries provide energy to the controller, controlling the motor through the controller. There is communication between the management module, the controller and the instrument system, thereby each of these is capable of knowing the working status of the other two, thus facilitating coordination and enabling a powerful protection function for the electrical system assembly of the electric automobile.

Abstract: A method of activating an electromagnetic actuator having at least one coil and a movable armature. The method includes the step in which the electromagnetic actuator is demagnetized by passing a sequence of electric current pulses with a current flow direction which alternates from one current pulse to the next and with a current size which decreases from one current pulse to the next, through the at least one coil, in order to reduce or eliminate any residual magnetic flux density in the electromagnetic actuator. The method also includes a step in which a position of the movable armature is determined, after the demagnetization step, by passing a measurement current pulse through the at least one coil.

Abstract: An apparatus and method for protecting a power system comprising a generator providing power to an alternating current bus, a power converter for converting alternating current power on the alternating current bus to direct current power on a direct current bus, and a direct current load powered by the direct current power on the direct current bus. An undesired condition is identified at the input to the power converter from the alternating current bus. The undesired condition is caused by at least one of the power converter, the direct current bus, or the load. The power converter is disconnected from the alternating current bus in response to identifying the undesired condition for at least a time delay. The time delay is selected such that the power converter is disconnected from the alternating current bus before the alternating current bus is disconnected from the generator due to the undesired condition.

Abstract: A method of estimating stator resistance of an induction motor includes applying voltage pulses through two phase paths of the motor for a plurality of electrical cycles to inject current in the motor, wherein the voltage pulses are applied until rotor flux of the motor is substantially stabilized and measuring stator voltage and stator current in response to the applied voltage pulses for each of the plurality of electrical cycles. The method also includes calculating the stator resistance based upon the measured stator voltages and the stator currents.

Abstract: Embodiments of the present disclosure relate to methods, systems and apparatus for estimating angular position and/or angular velocity of a rotor of an electric machine.

Abstract: A method and arrangement for determining the position of the drive mechanism of an electric machine from the current supplied thereto. Determination of the position is effected over two independent channels by measuring the three-phase current of the electric machine or motor, converting the measured values to the current space vector, calculating the angle of the current space vector within one electrical revolution, and determining the position of the motor. A current command, the field of which acts in the direction of the flux or field of the drive mechanism or rotor, is added within the motor stator.

Abstract: If it is predicted that the sum of the output of a servo motor and the output of a spindle motor exceeds power supplied by a rectifier unit, during a cutting operation, a motor drive control device controls alternating-current power of a first inverter unit so as to reduce the feed speed of at least one feed axis and controls alternating-current power of a second inverter unit so as not to limit torque of the spindle motor. Further, if it is predicted that the sum of the output of the servo motor and the output of the spindle motor exceeds power supplied by the rectifier unit, during an operation other than the cutting operation, the motor drive control device controls the alternating-current power of the second inverter unit so as to limit the torque so as not to reduce the feed speed.

Abstract: A protection relay for an electrical switching apparatus for a load includes a number of voltage sensors structured to sense voltage applied to the load, a number of current sensors structured to sense current flowing to the load, and a processor cooperating with the number of voltage sensors and the number of current sensors. The processor determines a fault current available at the load. An output cooperates with the processor. The output is structured to output the determined fault current and a number of: incident energy at the electrical switching apparatus, and a personal protective equipment level operatively associated with the electrical switching apparatus. The processor determines from the determined fault current the number of: the incident energy at the electrical switching apparatus, and the personal protective equipment level operatively associated with the electrical switching apparatus.

Abstract: Provided is a method of obtaining an image of a disc, in which the method obtains an image of an analysis or test result object of a disc by minimizing a difference between the positionings of a magnet of the disc and a magnet of a feeding unit, and an apparatus for driving a disc, wherein the apparatus performs the method. The method includes: fixing a positioning of a disc by using magnetic attraction between a first magnet installed on the disc and a second magnet installed on a feeding unit; minimizing a difference between the positionings of the first and second magnets; and obtaining an image of an analysis or test result object of the disc.

Abstract: A system for measuring current in an H-Bridge motor drive circuit and using that current to determine the output of a device powered by the motor. A particular embodiment is disclosed for a motor-driven fluid pump. Motor current is measured at predetermined pump pressures and flow rates to create calibration tables relating motor current to pump pressure. Once calibrated, the system determines pump pressure based on motor current by referring to the calibration tables. In an embodiment, the pump is driven to achieve a predetermined fluid dispense profile. The system monitors pump pressure by measuring motor current and determines if the dispense profile is being achieved and sets alarms if predetermined thresholds are not maintained. The system also detects pump wear based on the current measurements and issues warnings to the user in such conditions.

Abstract: In opening/closing control for the valve mechanism to which the return torque is applied in an opening direction or a closing direction of the valve, provided are a position control system for outputting a q-axis current command based on a position deviation between a target position command directed to the brushless DC motor and the coarse present position of the motor obtained by using the position detection sensor of a pulse output type, and a current control system in which a virtual current feedback is built for outputting a phase voltage command without a current sensor based on the q-axis current command and the coarse present position of the motor obtained by using the position detection sensor of the pulse output type.

Abstract: An electrical submersible pumping (ESP) system can include a pump located in a wellbore, a motor attached to the pump, a power source located at the surface, a cable electrically coupling the power source and the motor, and a current sensor. The ESP system can also include a controller communicating with the current sensor to calculate a voltage drop associated with the cable responsive to an impedance of the cable. The controller can also control a power source output voltage responsive to the calculated voltage drop. For example, the controller can adjust the power source output voltage to minimize a cable current while maintaining a minimum motor voltage. The controller can also control a motor shaft speed by changing a power source output voltage frequency to compensate for changing slip and adjust the power source output voltage to minimize the cable current while maintaining a minimum motor voltage.

Abstract: Embodiments of the present invention include circuits and methods for calibrating position displacement in a voltage controlled actuator. In one embodiment, a calibration circuit comprises an actuator having a control terminal for receiving a programmable control voltage to set a displacement, a switch that selectively decouples said programmable voltage from said control terminal and couples a reference current to said control terminal when the control terminal is decoupled from said control voltage, a comparator that senses a voltage difference between said control voltage and said control terminal, and a timer coupled to an output of the comparator. The timer measures a time period required to increase the control terminal voltage. The capacitance of the actuator may be determined and used to calibrate the position of the actuator.

Abstract: A move-sled-home device is used in an optical disc drive. The move-sled-home device includes a processing unit, a motor actuator, a sled, a sled motor, and a current-detecting unit. The processing unit outputs a control signal. The motor actuator generates a driving voltage according to the control signal. The sled motor generates a driving current according to the driving voltage to move the sled. The current-detecting unit is used for receiving and converting the driving current into an indicating signal, and issuing the indicating signal to the processing unit. During a move-sled-home action, the processing unit realizes a magnitude of the driving current according to the indicating signal, thereby determining whether the move-sled-home action is finished.

Abstract: A method of controlling a moving part of a voice coil motor to move from an first position to a second position, wherein the position of the moving part is controlled by the level of an electrical signal applied to a coil of the voice coil motor, a first level of the electrical signal corresponding to the first position, and a second level of the electrical signal corresponding to the second position, the method including: at a first time, changing the electrical signal from the first level to an intermediate level, the intermediate level being chosen such that a peak overshoot of the moving part corresponds to the second position; and at a second time calculated to correspond to a delay of half an oscillation period of the moving part after the first time, changing the electrical signal to the second level.

Abstract: One embodiment of the invention includes a disk-drive spindle motor power regulator system. The system includes a switching system comprising at least one power transistor for each of a plurality of phases of a disk-drive spindle motor. The system also includes a switching controller configured to generate a plurality of switching signals configured to control the at least one power transistor for each of the plurality of phases of the disk-drive spindle motor. The system further includes a current monitor configured to measure a magnitude of an individual phase current through at least one of the plurality of phases of the disk-drive spindle motor.

Abstract: Even when there is some degree of variation in the characteristics among components constituting a polyphase motor and a driving circuit therefor, current control signals of respective phases being input to the drive circuit have their amplitude finely adjusted by an amplitude control circuit, so that amplitude is uniform among armature currents of respective phases that are ultimately output from the drive circuit. The amplitude adjusting circuit is configured by gain variable amplifiers, for example. Thus, rotation fluctuation and vibration of the polyphase motor can be reduced.

Abstract: The present invention provides a stage apparatus capable of reducing a positioning time without increasing a positional deviation. A positioning control method of a sample stage apparatus includes: a high-speed movement step of moving a table to a high-speed movement target position at a first movement speed; a positional deviation correcting step of moving the table to a low-speed positioning step start position at a second movement speed that is lower than the first movement speed; a low-speed positioning step of moving the table to a target position at a third movement speed that is lower than the second movement speed. After the low-speed positioning step is completed, a rod connected to a motor returns to its original position to separate a pin of the rod side from a concave portion of the table side.

Abstract: A control system for a lifting device in which a load moves up or down or maintains its position by a rope that is wound up or down by the rotation of a servo motor. It includes a device for measuring a force, a first controller, a second controller and a switching device. A total force that is applied at the lower part of the rope caused by a force for controlling, the mass of the load, and the acceleration of the load is measured. The first controller, based on the measured force computes the direction and the speed of the servo motor, and outputs a signal to it. The second controller determines a stable condition using Popov's stability criterion. The switching device replaces the first controller with the second controller when the value that is measured by the measuring device becomes less than a threshold.

Abstract: An electric motor circuit for controlling an electric motor of a mirror adjustment mechanism includes a switch-off circuit that is provided with a current sensor for measuring the electrical supply current and, depending thereon, generating a voltage. In an embodiment, a current branch is configured to be rendered conductive in response to the generated voltage; an electronic switch is configured to interrupt the supply current as a result of the current branch being rendered conductive. The current branch may be configured to form a first branch of a current mirror which is out of balance and is dimensioned such that the first branch does not carry current under normal operating conditions of the motor, and a second branch is conductive. In an embodiment, upon the occurrence of a supply current that is greater than a predetermined critical level, the first branch is also rendered conductive.

Abstract: In opening/closing control for the valve mechanism to which the return torque is applied in an opening direction or a closing direction of the valve, provided are a position control system for outputting a q-axis current command based on a position deviation between a target position command directed to the brushless DC motor and the coarse present position of the motor obtained by using the position detection sensor of a pulse output type, and a current control system in which a virtual current feedback is built for outputting a phase voltage command without a current sensor based on the q-axis current command and the coarse present position of the motor obtained by using the position detection sensor of the pulse output type.

Abstract: A current detector unit has a current detecting portion detecting a current flowing between a three-phase inverter and a direct-current power supply as a detection current; a three-phase current detecting portion for detecting a three-phase current of the inverter based on the detection current; and a judging portion judging, based on the detection current, whether or not a target time point belongs to a period during which the three-phase current can be detected. If the judging portion judges that the target time point belongs to the period, the three-phase current detecting portion detects the three-phase current.

Abstract: Provided are an electric power steering device which is capable of determining a failure without using a motor current, and an electric power steering device which removes any motor current detecting unit for detecting the motor current such as a shunt resistor, and suppresses the heat generation and the power loss in the device, thereby making it possible to realize the downsized device, a reduction in the costs, and the higher efficiency. An electric power steering device according to the present invention includes: a motor coupled with a steering system; a drive control unit for controlling a drive of the motor; a motor impression voltage detecting unit for detecting an applied voltage of the motor; and an abnormality determining unit for determining abnormality based on a comparison result of the detected motor impression voltage and an output voltage of the drive control unit.

Abstract: Systems and methods are disclosed for detecting and indicating high-voltage presences on a machine. In one embodiment a high-voltage indication system is disclosed and may include a voltage detector configured to compare the voltage level associated with an element with a threshold voltage value, and provide an indication signal when the voltage level associated with the element is greater than the threshold voltage value. The system may also include an indicator powered by a separate power source independent from the voltage detector. The indicator may be configured to detect the indication signal provided by the voltage detector, and provide one or more warning signals in response to the indication signal.

Abstract: A method and arrangement for determining the position of the drive mechanism of an electric machine from the current supplied thereto. Determination of the position is effected over two independent channels by measuring the three-phase current of the electric machine or motor, converting the measured values to the current space vector, calculating the angle of the current space vector within one electrical revolution, and determining the position of the motor. A current command, the field of which acts in the direction of the flux or field of the drive mechanism or rotor, is added within the motor stator.

Abstract: An electrical apparatus comprising an amplifier having a first input, a second input, and an output. The apparatus further comprises a first electrical path coupled to the first input and having a first resistance and a first electrical path coupled to the second input and having a second resistance. The apparatus further comprises a second electrical path coupled to the second input and having a third resistance and a second electrical path, comprising an electrically-controllable resistance, coupled between the output and the first input. Further, the apparatus comprises circuitry for controlling the electrically-controllable resistance for adjusting a ratio between the electrically-controllable resistance and the third resistance to approximate a ratio between the first resistance and the second resistance.

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: An exposure apparatus that comprises a stage-that moves in the X-axis direction, an X-axis linear motor that drives the stage, a counter mass that moves in a direction opposite to the stage due to the action of the reaction force of the drive force of the stage in the X-axis direction by the motor, X-axis trim motors that drives the counter mass in the X-axis direction, and a control unit that controls the trim motors and gives the counter mass an initial velocity in the +X direction when the stage is moved via the motor, for example, in the +X direction. Accordingly, the strokes required for the movement of the counter mass can be shortened without increasing the size of the counter mass.

Abstract: A motor drive control device for controlling the driving of a brushless motor includes position detecting units (e.g. sensors or Hall elements), a drive signal determining unit and a drive signal outputting unit (an output circuit). The position detecting units are disposed in positions apart from each other by an electric angle of 120 degrees and output position detection signals representing the position of the rotor with respect to the stator. The drive signal determining unit determines drive signals for driving the 3-phase drive coils on the basis of the position detection signals. The drive signal outputting unit generates and outputs, to the 3-phase drive coils, the drive signals that have been determined by the drive signal determining unit.

Abstract: A method of optimizing a servo controller power required in the operation of two-dimensional flexure (Microelectronic Memory Storage) MEMS devices. Furthermore, provided is an arrangement for optimizing servo controller power in a two-dimensional flexure MEMS storage device through a utilization of the inventive method.

Abstract: A circuit arrangement and a method for adjusting the power consumption of a load of a cooling fan motor of a motor vehicle that can be operated by a direct-voltage system has at least one semiconductor switch in the supply current circuit of the load, and a control unit for triggering the semiconductor switch or switches. The load is connectable via at least one sense field-effect transistor to the direct-voltage system the measurement output of the sense FET is connected to the control unit, and the control unit furnishes a signal corresponding to the current consumption of the load at the respective operating point.

Abstract: A method for detecting and controlling output characteristics of a DC motor is provided in the present invention, wherein an input impedance related to the DC motor is measured for analyzing the output characteristics of the DC motor so that the output characteristics of the DC motor is capable being controlled according to the requirement of usage. By means of the foregoing method, the present invention further provides a self-propelled apparatus which functions to detect and control the output of the DC motor for maintaining the moving speed according to the environment status and road condition.

Abstract: Self-sensing feedback functionality for electromechanical actuators/motors is provided for use in operation and/or as a redundant safety mechanism to attain safety certification without adding extra bulk or wiring to the motor. An actuator can be manufactured having one or more saliencies that cause a spatial variance of inductance. A high frequency signal can be injected into the actuator and sampled to determine a current, voltage, or other electrical parameter. The parameter can be evaluated against the known saliencies of the actuator to determine a position of the actuator and/or an associated rotor. Additionally, the position can be evaluated as a function of time to determine a velocity. This can provide an alternative method for operating the electromechanical actuator according to the position/velocity provided. Additionally, this can provide a redundant feedback channel for safety certification without requiring additional actuator parts.

Abstract: Even when there is some degree of variation in the characteristics among components constituting a polyphase motor and a driving circuit therefor, current control signals of respective phases being input to the drive circuit have their amplitude finely adjusted by an amplitude control circuit, so that amplitude is uniform among armature currents of respective phases that are ultimately output from the drive circuit. The amplitude adjusting circuit is configured by gain variable amplifiers, for example. Thus, rotation fluctuation and vibration of the polyphase motor can be reduced.

Abstract: A control system which is capable of avoiding an overloaded state of an actuator without using sensors or the like. An ECU 2 of the control system 1 calculates a lift control input U_Liftin to a variable valve lift mechanism 50 with an algorithm expressed by equations (2) to (5), such that the valve lift Liftin follows up a target valve lift Liftin_cmd, calculates a cumulative value Simot by cumulative calculation of the product of the value Imot of electric current flowing through the variable valve lift mechanism 50 and a sampling time period Stime, and when SImot?Simot_J1 holds, sets two parameters pole_f_lf and ploe_lf to respective predetermined failure-time parameters pole_f_lf_J1 and ploe_lf_J1 which cause the lift control input U_Liftin to become smaller than when Simot<Simot_J1 holds.

Abstract: A method of optimizing a servo controller power required in the operation of two-dimensional flexure (Microelectronic Memory Storage) MEMS devices. Furthermore, provided is an arrangement for optimizing servo controller power in a two-dimensional flexure MEMS storage device through a utilization of the inventive method.

Abstract: A car control apparatus including a wheel sensor, wheel torque calculating means for calculating wheel torque from the wheel speed, drive force detecting means for detecting drive force generated by an electric motor, car body drive force calculating means for calculating car body drive force from the above drive force and wheel torque, car body drive force fluctuating component extracting means for extracting multiple frequency band fluctuating components of the car body drive force, and drive or braking force control unit for controlling the running state of a car.

Abstract: A Bemf detect circuit is configured for modeling Bemf error via calculation of time correlations associated with two or more different non-calibrated sense resistor gain values to derive a calibrated sense resistor gain value. A method is provided for calibrating a Bemf detector circuit by setting a sense resistor gain to a plurality of different gain values, observing Bemf sample values for each of the gain values, and deriving a calibrated gain value by non-iteratively modeling the relationship between the gain values and the associated Bemf sample values.

Abstract: A method for estimating values assumed at a certain instant of each period by currents flowing respectively in two distinct windings of a poly-phase load controlled in a space vector modulation (SVM) mode, using a same measuring device, may include coupling the measuring device to the first winding and measuring a current flowing therethrough with an anticipation from the certain instant smaller than or equal to an SVM half-period. The method may also include coupling the measuring device to the second winding, measuring a current flowing therethrough at the certain instant, coupling the measuring device to the first winding, and measuring a current flowing therethrough with a delay equal to the anticipation. The method may also include estimating a value assumed at the certain instant by the current flowing through the first winding based upon the two measured values with the anticipation and with the delay respectively.

Abstract: The invention relates to a method and a circuit layout for the position and/or speed control of a linear drive, in particular a servo drive for a linear robot. An electric motor is supplied via a converter (3) with a control unit (4) and the motor position is determined, in particular in a sensor-free manner or via a position sensor (7). This motor position signal and an acceleration signal generated via an accelerometer (5) provided in the control unit (4) and arranged on the moving part of the linear drive are mathematically converted to a speed signal. This speed signal is used for controlling the drive. The accelerometer (5) is embodied as a microelectromechanical system (MEMS) and integrated into the entrained control unit (4).

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 speed controller includes a speed integration compensation low-pass filter, an integral control system, a proportional control system, and a multiplication device means. The speed integration compensation low-pass filter has a transfer function corresponding to a delay of a speed control system. The integral control system 136 is multiplied by an integral gain by a multiplier and integrated by a speed integrator before being supplied to an adder. The adder adds an output of the proportional control system and an output of the integral control system and outputs the result to the multiplier, which in turn multiplies the output of the adder by a proportional gain and outputs the result as a torque command. The multiplication means multiplies the output of the integral control system and the output of the proportion control system by a speed proportional gain and outputting the value of the torque command.