METHOD AND APPARATUS FOR INCREASING A CURRENT SENSING RANGE IN A POLYPHASE MOTOR SYSTEM

摘要

A method of increasing a current sensing range for a vehicle or other polyphase motor system includes measuring phase currents delivered to a motor of the system. A controller calculates an absolute value of each phase current, compares each calculated absolute value to a saturation limit to determine whether only one sensor is saturated, and extrapolates a phase current value of the saturated sensor. The calculated temporary phase current is used as the extrapolated phase current value for the saturated sensor, and a control action is executed using the extrapolated phase current value only when the calculated temporary phase current value exceeds the measured value for the saturated sensor and a sign of the calculated temporary phase current value matches that of the measured value for the saturated sensor. A system includes the motor, a power inverter module, phase current sensors, and a controller which executes the method.

主权项

1. A method of increasing a current sensing range in a system having a polyphase motor, the method comprising:
measuring, via a plurality of phase current sensors having a calibrated saturation limit, each of a plurality of phase currents delivered to the polyphase motor; calculating, via a controller, an absolute value of each of the measured phase currents; comparing each of the calculated absolute values to the calibrated saturation limit to determine whether only one of the phase current sensors is saturated; extrapolating a phase current value of the one saturated sensor using the measured phase currents of the unsaturated sensors, including:
calculating a temporary phase current value as a function of the phase currents of the unsaturated sensors;determining whether an absolute value of the calculated temporary phase current exceeds the measured value for the one saturated sensor;determining whether a sign of the calculated temporary phase current matches a sign of the measured value for the one saturated sensor; andusing the calculated temporary phase current as the extrapolated phase current value for the saturated sensor; and executing a control action of the polyphase motor, via the controller, using the extrapolated phase current value only when the signs match and the calculated temporary phase current value exceeds the measured value for the saturated sensor, including at least one of controlling a function of the polyphase motor and recording a diagnostic code indicating a state of health of the polyphase motor.