Patent application number | Description | Published |
20080290826 | Motor Controller - A motor controller stores values corresponding to predetermined equivalent resistance which corresponds to power loss generated by switching on and off switching elements. Voltage command values are determined by adding voltage drop values determined from values corresponding to the equivalent resistance and values of current flowing in the switching elements to target applied voltage values corresponding to current command values which correspond to target output of a motor. The switching elements arranged in a power supply line to the motor are switched on and off by control signals generated according to the voltage command values. | 11-27-2008 |
20090079373 | MOTOR CONTROLLER AND ELECTRIC POWER STEERING SYSTEM - A current sensor of a motor controller detects the current applied to a motor drive circuit and thus a phase where a failure cannot be detected would occur without taking any measures. However, an abnormal current monitor section contained in a microcomputer receives a voltage signal of an average value of the currents detected in the current sensor by allowing a signal to pass through a first LPF having a cutoff frequency sufficiently lower than the frequency of a PWM signal. Therefore, whether or not the value is within a predetermined normal range is checked, whereby whether or not some failure containing a failure of the current sensor occurs can be easily determined about every phase. | 03-26-2009 |
20090256503 | MOTOR CONTROL APPARATUS AND ELECTRIC POWER STEERING SYSTEM - If the magnitude of a command voltage vector is greater than a predetermined voltage value indicated by a voltage limit circle, the magnitude of a voltage vector, which corresponds to a q-axis current and which forms the command voltage vector, is adjusted so that the magnitude of the command voltage vector is equal to or less than the predetermined voltage value. Then a q-axis current estimated value is obtained based on i) the ratio of the magnitude of the voltage vector from the q-axis current after adjustment to the magnitude of the voltage vector from the q-axis current before adjustment, and ii) a q-axis current command value. | 10-15-2009 |
20100045217 | Motor control apparatus and electric power steering apparatus - An angle calculation portion of a motor control apparatus determines an angle θ of a rotor, and an angular velocity calculation portion determines an angular velocity ωe of the rotor. A command current calculation portion determines command currents id* and iq* on dq axes, based on a steering torque T and a vehicle speed S. An open-loop control portion determines command voltages vd and vq on the dq axes based on the command currents id* and iq* and the angular velocity ωe, according to circuit equations of a motor. A dq-axis/three-phase conversion portion converts the command voltages vd and vq to command voltages of three phases. A three-phase voltage correction portion corrects the command voltage so that an actual time average value of a voltage applied to each phase is equal to a time average value of a voltage that is to be applied to the phase if the voltage is not decreased, in order to compensate for a decrease in the applied voltage. By performing the correction, it is possible to eliminate or suppress a decrease in control accuracy due to a wiring resistance and the like. | 02-25-2010 |
20120080259 | MOTOR CONTROL DEVICE AND ELECTRIC POWER STEERING APPARATUS - An angular velocity estimate (ωe) used in motor control of an electric power steering is obtained as follows. In a first state period during which the motor substantially stops its rotation, a resistance calculation unit calculates a motor resistance value (Rc) on the basis of a detected value (Vm) of motor voltage and a detected value (Im) of motor current. An average calculation unit obtains an average value (Rav) of the calculated resistance values (Rc) in a retained period. A current-resistance characteristic that associates motor current with motor resistance is held in a characteristic holding unit, and a characteristic updating unit updates the current-resistance characteristic on the basis of the average value (Rav). An estimate calculation unit calculates the angular velocity estimate (ωe) on the basis of the detected value (Vm) of motor voltage, the detected value (Im) of motor current and a motor resistance value (Rm) obtained from the current-resistance characteristic. | 04-05-2012 |
20120139532 | ROTATION ANGLE DETECTION DEVICE - An output signal V | 06-07-2012 |
20120143563 | ROTATION ANGLE DETECTION DEVICE - A first rotation angle computing unit computes a first rotation angle corresponding to a rotation angle of a rotor based on an output signal of a first magnetic sensor and an output signal of a second magnetic sensor. A second rotation angle computing unit computes a second rotation angle corresponding to the rotation angle of the rotor based on the output signal of the second magnetic sensor and an output signal of a third magnetic sensor. A rotation angle selection unit determines a final rotation angle using the first rotation angle and the second rotation angle. | 06-07-2012 |
20120158340 | ROTATION ANGLE DETECTION DEVICE - A rotation angle calculation unit includes a first rotation angle calculation portion, a second rotation angle calculation portion, a third rotation angle calculation portion, an abnormality monitoring portion, and a final rotation angle calculation portion. The abnormality monitoring portion determines, based on a first output signal, a second output signal, and a third output signal, whether the first to third output signals are each normal or abnormal. The final rotation angle calculation portion calculates a final rotation angle based on the final determination result obtained by the abnormality monitoring portion and the first to third rotation angles calculated by the first to third rotation angle calculation portions, respectively. | 06-21-2012 |
20120158341 | ROTATION ANGLE DETECTION DEVICE - A rotation angle calculation unit calculates a zero-crossing time point when a zero-crossing is detected for an output signal V | 06-21-2012 |
20120182008 | ROTATION ANGLE DETECTING DEVICE - Three magnetic sensors are arranged around a rotor at predetermined angular intervals about the rotation axis of the rotor. Sinusoidal signals that have a phase difference of a predetermined degree of 45° are output from the respective magnetic sensors. A rotation angle computing device detects a magnetic pole transition in a first output signal as follows. Specifically, the rotation angle computing device detects a magnetic pole transition in the first output signal based on a value having a larger absolute value between a current value of the second sinusoidal signal and a current value of the third sinusoidal signal, an immediately preceding value of the first sinusoidal signal and a current value of the first sinusoidal signal. | 07-19-2012 |
20120182009 | ROTATION ANGLE DETECTING DEVICE - Three magnetic sensors are arranged around a rotor at predetermined angular intervals about the rotation axis of the rotor. Sinusoidal signals having a phase difference of 120° are output from the magnetic sensors. A rotation angle computing device detects a magnetic pole transition in a first output signal as follows. The rotation angle computing device detects a magnetic pole transition in the first output signal based on a current value of one of the second and third sinusoidal signals, an absolute value of a difference between an immediately preceding value and the current value of the one of the second and third sinusoidal signals being larger than an absolute value of a difference between an immediately preceding value and the current value of the other of the second and third sinusoidal signals, an immediately preceding value of the first sinusoidal signal and a current value of the first sinusoidal signal. | 07-19-2012 |
20120227514 | ROTATION ANGLE DETECTION DEVICE AND TORQUE DETECTION DEVICE - A rotor includes a cylindrical magnet having a plurality of magnetic pole pairs. There are two types of the magnitude of magnetic force in the magnetic pole pairs, that is, a relatively large first magnetic force and a second magnetic force that is smaller than the first magnetic force. Three magnetic sensors are arranged around the rotor. A rotation angle computing device detects the peak values of output signals of the respective magnetic sensors. Then, the rotation angle computing device identifies the magnetic pole pair, sensed by the first magnetic sensor, based on a combination of the local maximum values of the three output signals. | 09-13-2012 |
20120229126 | ROTATION ANGLE DETECTION DEVICE - When the zero-crossing of one of the output signals of magnetic sensors has been detected, a rotation angle computing device identifies a magnetic pole sensed by the first magnetic sensor based on the other two output signals. Subsequently, the rotation angle computing device identifies the magnetic pole sensed by the second magnetic sensor and the magnetic pole sensed by the third magnetic sensor based on the magnetic pole sensed by the first magnetic sensor. After that, the rotation angle computing device corrects the amplitude of the output signal of each magnetic sensor based on the identified magnetic poles respectively sensed by the magnetic sensors. Then, the rotation angle computing device computes the electric angle θe of the rotor based on the corrected output signals. | 09-13-2012 |
20120232839 | ROTATION ANGLE DETECTION APPARATUS - A first third harmonic component removing portion calculates an approximate value (sin θ) | 09-13-2012 |
20120319680 | ROTATION ANGLE DETECTION DEVICE - Upon detecting a peak value from output signals of one of either a first or a second magnetic sensor, an rotation angle computation device identifies, on basis of an amplitude compensation table corresponding to the one magnetic sensor for which the peak value was detected, a pole number of a magnetic pole sensed by the magnetic sensor. Then, based on the identified pole number and a magnetic pole identification table, a pole number of a magnetic pole sensed by the other magnetic sensor is identified. The pole numbers of the magnetic poles sensed by the respective magnetic sensors are thus identified, and the rotation angle computation device compensates the output signals of the respective magnetic sensors using amplitude compensation gains corresponding to the sensed magnetic poles (magnetic pole pair). | 12-20-2012 |
20130035896 | ROTATION ANGLE DETECTION DEVICE - Angular widths of respective magnetic poles of a detection rotor are stored and divisions are set for respective magnetic pole pairs. Based on output signals from first and second magnetic sensors, a rotation angle computation unit computes first and second rotation angles that are rotation angles within the corresponding division. Based on the angular widths, the rotation angle computation unit identifies the magnetic pole sensed by the first magnetic sensor and computes a first absolute rotation angle using the first rotation angle. Based on the identified magnetic pole and the second rotation angle, the rotation angle computation unit computes a second absolute rotation angle. The rotation angle of the detection rotor is computed based on the first and second absolute angles. | 02-07-2013 |
20130197761 | MOTOR CONTROL DEVICE AND ELECTRIC POWER STEERING DEVICE - A motor control device for driving a brushless motor includes a current detecting unit which detects respective phase currents which flow into the brushless motor; a control calculation unit which calculates instruction values showing respective phase voltages to be applied to the brushless motor, and outputs the instruction values as phase voltage instruction values; a phase resistance calculation unit which calculates respective phase resistance values based on detection values of the respective phase currents detected by the current detecting unit, and the instruction values of the respective phase voltages applied to the brushless motor at the time of the detection of the detection values; a correction unit which corrects the phase voltage instruction values according to the respective phase resistance values calculated by the phase resistance calculation unit; and a driving unit which drives the brushless motor based on the phase voltage instruction values after correction by the correction unit. | 08-01-2013 |
20130312540 | TORQUE DETECTING APPARATUS - A torque detecting apparatus detects a torque applied to a first shaft, based on a relative rotational displacement between the first shaft and a second shaft caused by torsion in a coupling shaft which couples the first shaft and the second shaft. The torque detecting apparatus includes: first and second magnets which are coupled to the first shaft and the second shaft so as to rotate together with the first shaft and second shaft, respectively; and a plurality of magnetic sensors which are disposed between the first magnet and the second magnet and which detect a rotational angle of the first shaft and a rotational angle of the second shaft. | 11-28-2013 |
20140116792 | MATERIAL HANDLING AND STAIR CLIMBING VEHICLE - In a material handling and stair climbing vehicle, when the vehicle is shifted from a state where the wheels with two axles are grounded on a travelling surface to a standing state achieved by the wheels with one axle, a main body portion is turned around support shafts with respect to supporting portions in the two-axle wheel grounded state. Then, an inertial force around the support shafts is generated by reducing the speed of turning of the main body portion with respect to the supporting portions. Then, the vehicle is shifted to the standing state achieved by the wheels with one axle by turning the supporting portions around the axles of the wheels with one axle, which are grounded on the travelling surface, by the inertial force. | 05-01-2014 |