Abstract: To prevent a step-out of a permanent magnet synchronous type motor (1), a motor control device (3a) is provided to include a flux control unit (16) for deriving an excitation current command value (i?*) according to the rotation speed (?e) of the motor, and a voltage shortage determination unit (30) for determining whether or not the supply voltage to the motor is running short based on the excitation current command value (i?*). When a negative excitation current command value (i?*) is smaller than a negative determination threshold value, the motor control device determines that the supply voltage is running short and prohibits an increase of the rotation speed or decreases the rotation speed.

Abstract: To estimate a fluctuation component of the torque generated at the motor accurately, a motor control device (3) which controls a motor with a stator having armature winding and a rotor having a permanent magnet is provided to include a torque fluctuation component estimation unit for estimating a torque fluctuation component generated at the motor based on flux-linkage of the armature winding and an armature current that flows the armature winding. The torque fluctuation component estimation unit estimates the torque fluctuation component (Trp) based on an inner product (Fd·id+Fq·iq) of a flux-linkage vector which is a vectorial representation of the flux-linkage and a current vector which is a vectorial representation of the armature current.

Abstract: To estimate an initial magnetic pole position, estimated control axes corresponding to the d-axis and q-axis are set as the ?-axis and ?-axis, and a with high frequency rotation voltage or alternating voltage on the ?? coordinate system applied to the motor. A high frequency current ih flowing in the motor is then extracted from a detected motor current (armature current) and a direct current component (ih?×ih?)DC of a product of the ?-axis and ?-axis components of the high frequency current ih is derived. Alternatively, the ??-axis component ich? and the ??-axis component 66 of the high frequency current ih that are shifted by ?/4 in electric angle from the ?-axis and the ?-axis are used to obtain a direct current component of their product (ich?×ich?)DC. The magnetic pole position is then estimated by computing the axial error ?? between the ?-d axes utilizing the direct current components.

Abstract: An inverter control apparatus that controls a three-phase inverter which transforms a direct-current voltage into an alternating three-phase voltage, the inverter control apparatus includes: a voltage command vector generation portion that generates a first voltage command vector for specifying a vector of a voltage to be applied to a three-phase load that is connected to the inverter; a voltage command vector correction portion that in performing overmodulation with the inverter, corrects the first voltage command vector by setting a limit onto a coordinate-axis component of the first voltage command vector on an ab coordinate system to generate a second voltage command vector, wherein the inverter is so controlled that a voltage depending on the second voltage command vector is applied to the load, and the ab coordinate system is a coordinated system that depending on a phase of the first voltage command vector with respect to a predetermined fixed axis on a two-dimensional fixed coordinate system, rotates

Abstract: Provided is a motor control device including a voltage specifying unit which generates a specified voltage signal indicating a target value of an applied voltage to a motor on the basis of a specified current signal indicating a target value of supplied current to the motor, so as to control the motor in accordance with the specified voltage signal. An update unit is further provided, which sequentially updates a specified field current signal that is a field current component of the specified current signal to be given to the voltage specifying unit on the basis of difference information between a value of the specified voltage signal and a limit voltage value defined as an upper limit value of the applied voltage. The update unit includes a low pass filter. The specified field current signal after the update is generated on the basis of a signal obtained by passing the specified field current signal before the update through the low pass filter and the difference information.

Abstract: An inverter control device includes a phase current detection unit which is connected to a current sensor. The current sensor detects current flowing between a three-phase inverter which converts a DC voltage into AC three-phase voltages and a DC power supply which outputs the DC voltage, and the phase current detection unit detects phase current flowing in each phase of the inverter from a result of detection by the current sensor, so as to control the inverter on the basis of a result of detection by the phase current detection unit. The phase current detection unit includes an estimation block which estimates phase current of an intermediate voltage phase or current corresponding to the phase current of the intermediate voltage phase as a first estimated current, and estimates phase current of a maximum voltage phase or phase current of a minimum voltage phase using the first estimated current so that each phase current can be detected.

Abstract: A motor control device includes a motor current detector for detecting motor current flowing in a three-phase motor based on current flowing between an inverter driving the motor and a DC power supply, a specified voltage vector generating portion for generating a specified voltage vector indicating a voltage vector to which an applied voltage to the motor should follow based on a magnetic flux linkage of an armature winding of the motor, a specified voltage vector correcting portion for correcting the generated specified voltage vector, and a magnetic flux estimating portion for estimating the magnetic flux linkage based on the motor current and the specified voltage vector after the correction. The motor control device controls the motor via the inverter in accordance with the specified voltage vector after the correction.

Abstract: A motor control device that includes a first speed estimator estimating the rotation speed of the rotor of a permanent-magnet synchronous motor and that controls the motor so that a first estimated rotation speed estimated by the first speed estimator follows the specified speed value further includes a second speed estimator that estimates the rotation speed of the rotor by an estimation method different from that used by the first speed estimator. The motor control device detects synchronization failure based on a comparison between a second estimated rotation speed estimated by the second speed estimator and the first estimated rotation speed or the specified speed value.

Abstract: A rotor (20) has a four-pole permanent magnet (31A) embedded in a rotor layered core. A gap (31G) is also arranged together with the permanent magnet between an inner circumferential layered core and an outer circumferential layered core. A permanent magnet of one pole is formed by two permanent magnets (31A and 31B) arranged so as to sandwich a gap (31G). When Tm is the thickness of the permanent magnet in the inter-pole direction, the air gap thickness in the d-axis direction is set to [½×Tm] or below.

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: A motor control device that includes a first speed estimator estimating the rotation speed of the rotor of a permanent-magnet synchronous motor and that controls the motor so that a first estimated rotation speed estimated by the first speed estimator follows the specified speed value further includes a second speed estimator that estimates the rotation speed of the rotor by an estimation method different from that used by the first speed estimator. The motor control device detects synchronization failure based on a comparison between a second estimated rotation speed estimated by the second speed estimator and the first estimated rotation speed or the specified speed value.

Abstract: A motor control device includes a current detecting portion that detects current flowing between an inverter for driving a three-phase motor and a DC power supply for supplying DC voltage to the inverter, a current estimator that estimates a current vector of the motor on a rotating coordinate that rotates along with rotation of a rotor of the motor. The motor control device detects motor current flowing in the motor by using one of a detecting result of the current detecting portion and an estimation result of the current estimator, so as to control the motor via the inverter based on the detected motor current. The current estimator estimates the current vector based on the motor current detected in the past and a specified voltage value, for example.

Abstract: A current detecting unit detects three phase current of a three-phase inverter from current flowing between the inverter and a DC power supply. The current detecting unit includes a specified voltage vector generating portion that generates a specified voltage vector indicating a voltage vector that three-phase voltage of the inverter should follow, and a specified voltage vector correcting portion that corrects the generated specified voltage vector. The inverter is controlled in accordance with the specified voltage vector after the correction.

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: A motor control device that includes a first speed estimator estimating the rotation speed of the rotor of a permanent-magnet synchronous motor and that controls the motor so that a first estimated rotation speed estimated by the first speed estimator follows the specified speed value further includes a second speed estimator that estimates the rotation speed of the rotor by an estimation method different from that used by the first speed estimator. The motor control device detects synchronization failure based on a comparison between a second estimated rotation speed estimated by the second speed estimator and the first estimated rotation speed or the specified speed value.

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: An inverter control apparatus that controls a three-phase inverter which transforms a direct-current voltage into an alternating three-phase voltage, the inverter control apparatus includes: a voltage command vector generation portion that generates a first voltage command vector for specifying a vector of a voltage to be applied to a three-phase load that is connected to the inverter; a voltage command vector correction portion that in performing overmodulation with the inverter, corrects the first voltage command vector by setting a limit onto a coordinate-axis component of the first voltage command vector on an ab coordinate system to generate a second voltage command vector, wherein the inverter is so controlled that a voltage depending on the second voltage command vector is applied to the load, and the ab coordinate system is a coordinated system that depending on a phase of the first voltage command vector with respect to a predetermined fixed axis on a two-dimensional fixed coordinate system, rotates

Abstract: To estimate an initial magnetic pole position in a short time, estimated axes for control that correspond to the d-axis and the q-axis are set as the ?-axis and the d-axis, and a high frequency rotation voltage or alternating voltage on the ?? coordinate system is applied to the motor. A high frequency current ih that flows in the motor due to the application of the high frequency voltage is extracted from a detected motor current (armature current) and a direct current component (ih?×ihd)DC of a product of the ?-axis and d-axis components of the high frequency current ih is derived. On the other hand, the ??-axis component ich? and the ??-axis component ichd of the high frequency current ih that are shifted by p/4 in electric angle from the ?-axis and the d-axis are obtained and a direct current component of their product (ich?×ichd)DC is obtained. Thereafter, the magnetic pole position is estimated by computing the axial error ?? between the ?-d axes utilizing the two direct current components.

Abstract: To estimate a fluctuation component of the torque generated at the motor accurately, a motor control device (3) which controls a motor with a stator having armature winding and a rotor having a permanent magnet is provided to include a torque fluctuation component estimation unit for estimating a torque fluctuation component generated at the motor based on flux-linkage of the armature winding and an armature current that flows the armature winding. The torque fluctuation component estimation unit estimates the torque fluctuation component, (Trp) based on an inner product (Fd·id+Fq·iq) of a flux-linkage vector which is a vectorial representation of the flux-linkage and a current vector which is a vectorial representation of the armature current.

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.