Hitachi Automotive Systems, Ltd.

Fumiya Iijima

Tomishige Yatsugi

Tomonobu Koseki

The present invention relates to a motor driving device and a method for measuring a phase current in a motor driving device, and specifically relates to a technique of measuring three phase currents of a three-phase brushless motor using a current sensor for measuring the DC bus current in the inverter. The control unit according to the present invention shifts a pulse phase of a PWM pulse such that pulse phases of the three phase PWM pulses in a first PWM cycle of the PWM control differ from those in a second PWM cycle of the PWM control, and measures the three phase currents from the output of the current sensor in these two first and second PWM cycles. The control unit calculates an offset error of the current sensor from these three phase current measurements and learns a correction value used for performing offset correction on the electric-current measurement.

Motor driving device and method for measuring phase current in motor driving device

Provided is a control devicefor an electric motorwhich includes multiple energization systems each including an inverter and coils corresponding to different phases, and which generates a steering assist force in an electric power steering system. Control devicediagnoses whether any of invertersA andB fails, and, when either of the inverters is diagnosed as having failed, reduces the output ratio of the failing inverter to 0% while increasing the output ratio of the normally operating inverter to 100% so as to prevent a drop in the total output from all the inverters after the failure-positive diagnosis. If steering operation is performed after the failure-positive diagnosis, control deviceperforms overheat protection processing for gradually lowering the limit value for the total output from all the inverters in accordance with the sensed temperature of the normally operating inverter.

Device and method for controlling electric motor

An electronic control unit includes: inverter circuits of first and second systems driving a multiphase motor with coil sets on a coil set basis; first and second phase potential detecting circuits detecting potentials of at least one phase of current supply paths from the inverter circuits to the coil set; and a diagnosis apparatus detecting a failure based on potentials detected by the first and second phase potential detecting circuits. Under condition that the inverter circuit of the first system turns ON the upper or lower arm switching element corresponding to one phase of the first coil set and turns OFF the other one so that the inverter circuit of the second system has a high-impedance output, when the potential detected by the second phase potential detecting circuit corresponds to an output potential of the inverter circuit of the first system, the diagnosis apparatus determines that a short-circuit failure occurs.

Electronic control unit and control method for the same

Provided is an electronic control device including inverter circuits of first and second systems for driving a multiphase motor with first and second coil sets by use of upper and lower arm switching elements selectively controlled to be ON/OFF in each coil of the first and second coil sets. The upper arm switching elements of all phases in the inverter circuit of the first system are turned ON to apply a high potential to the first coil set, and the lower arm switching elements of all phases in the inverter circuit of the second system are turned ON to control the second coil set to a low potential. When a value of current flowing through the lower arm switching element in the inverter circuit of the second system is a predetermined value or more, it is determined that a power supply failure has occurred between the first and second systems.

Electronic control device and control method thereof

Provided is a control device for an electric motor which includes multiple energization systems each including an inverter and coils corresponding to different phases, and which generates a steering assist force in an electric power steering system. Control device diagnoses whether any of invertersA andB fails, and, when either of the inverters is diagnosed as having failed, reduces the output ratio of the failing inverter to 0% while increasing the output ratio of the normally operating inverter to 100% so as to prevent a drop in the total output from all the inverters after the failure-positive diagnosis. If steering operation is performed after the failure-positive diagnosis, control device performs overheat protection processing for gradually lowering the limit value for the total output from all the inverters in accordance with the sensed temperature of the normally operating inverter.

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Isesaki, Japan

Fumiya Iijima