Nidec Corporation

Ahmad Ghaderi

Hiromitsu Ohashi

A motor control method includes acquiring n-phase currents, where n is an integer of three or more, of a first inverter, a GND current of the first inverter, n-phase currents of a second inverter, and a GND current of the second inverter, generating a first fault signal indicating presence or absence of a shunt resistor fault in the first inverter based on the n-phase currents and GND current of the first inverter and generating a second fault signal indicating presence or absence of a shunt resistor fault in the second inverter based on the n-phase currents and GND current of the second inverter, referring to a table representing a relationship between a set of levels of the first fault signal and the second fault signal and control modes and selecting one of the control modes, and controlling a motor in accordance with the selected control mode.

Motor control method, power conversion device, motor module, and electric power steering device

A power converter includes a first inverter, a second inverter, and a switching circuit including first and second switching elements. In a state in which, in the first inverter, potentials at a first node in a high side and a second node in a low side are equal to each other, and potentials at first ends of two-phase windings of n-phase windings with n being an integer of 2 or more are equal to each other, two-phase windings are energized using two legs connected to second ends of the two-phase windings of n legs of the second inverter while performing switching operations on the first and second switching elements of the switching circuit at a predetermined duty ratio.

Power converter, motor driving unit, and electric power steering device

A motor control method includes acquiring at least one measured torque angle and two estimated torque angles, obtaining all combinations of two torque angles that are combinable with respect to a set of the at least one measured torque angle and the two estimated torque angles and performing an arithmetic operation to determine an error for each combination, selecting a control mode of the motor from control modes including a sensor mode, a sensorless mode, and a shutdown mode, the selecting being performed by referring to a table representing a relationship between the control modes and reference patterns relating to the calculated error group, and controlling the motor in accordance with the selected control mode.

Motor control method, motor control system, and electric power steering system

A power converter to convert power from a power supply into power supplied to a motor including n-phase windings, where n is an integer of 3 or more, in which first ends thereof are Y-connected and includes an inverter connected to second ends of the n-phase windings, a phase separation relay circuit to switch connection and disconnection between the power supply and the n-phase windings for each phase, a neutral point leg connected to a neutral point node of the motor, in which the first ends of the n-phase windings are Y-connected, and a neutral point separation relay circuit to switch connection and disconnection between the power supply and the neutral point node.

A power conversion device includes first and second inverters connectable to at least one of first and second coil groups, a first separation relay circuit connected to the first inverter, a second separation relay circuit connected to the second inverter, a third separation relay circuit connected between the first separation relay circuit and the first coil group, a fourth separation relay circuit connected between the second separation relay circuit and the second coil group, and n connection lines to, for each phase, connect n nodes between the first and third separation relay circuits and n nodes between the second and fourth separation relay circuits, where n is an integer of 3 or more.

Power conversion device, motor drive unit, and electric power steering device

A motor control method includes acquiring three current values of three-phase currents flowing through a motor, the three current values being detected by three current sensors, and two rotor angles of the motor, the two rotor angles being detected by two position sensors; performing six ways of calculation using two of the three current values and one of the two rotor angles; identifying at least one failed sensor from among the current sensors as well as the position sensors, using a table showing a relationship between a failed sensor and a pattern of a result of each of the six ways of calculation; selecting, as a normal sensor, a sensor different from the at least one failed sensor identified; and controlling the motor using the normal sensor selected.

Motor control method, motor drive system, and electric power steering system

A motor controller includes target current value generating circuitry that generates a d-axis target current value and q-axis target current value, motor current value generating circuitry that generates a d-axis motor current value and a q-axis motor current value of current supplied to a motor, command voltage value generating circuitry that generates a d-axis command voltage value from a difference between the d-axis motor current value and the d-axis target current value and a q-axis command voltage value from a difference between the q-axis motor current value and the q-axis target current value, command voltage value converting circuitry that converts the d-axis command voltage value and the q-axis command voltage value into three-phase command voltage values, and command voltage value modifying circuitry that modifies the three-phase voltage values based on motor flux values and target flux values.

Motor controller and a motor system

A motor control method includes acquiring a component BEMFon an &#x3b1;-axis and a component BEMFon a &#x3b2;-axis of counter electromotive force of a motor in an &#x3b1;&#x3b2;-fixed coordinate system; performing time differentiation on the component BEMFon the &#x3b1;-axis and the component BEMFon the &#x3b2;-axis; obtaining a difference value between first and second multiplication values, the first multiplication value being obtained by multiplying the component BEMFon the &#x3b1;-axis by a differential value of the component BEMFon the &#x3b2;-axis, the second multiplication value being obtained by multiplying the component BEMFon the &#x3b2;-axis by a differential value of the component BEMFon the &#x3b1;-axis; detecting a rotation direction of the rotor based on the difference value; and controlling the motor based on a detection result of the rotation direction of the rotor.

A motor controller of a permanent magnet motor includes an inverter, a torque and flux calculator configured to estimate or measure torque and flux generated in the permanent magnet motor as calculated torque flux, based on an output from the inverter and a rotor angle of the permanent magnet motor, a switching pattern selector configured to input a signal to the inverter to select one of a plurality of switching patterns based on comparison results of a reference torque and the calculated torque and a reference flux and the calculated flux, and a flux phase angle, and a reference flux calculator configured to compare a highest phase flux out of three phase fluxes obtained by the torque and flux calculator with a flux limit and to reduce the reference flux when the maximum phase flux is higher than the flux limit.

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Kyoto, Japan

Ahmad Ghaderi