Apparatus and method for diagnosing phase current sensor failure of 3-phase inverter
The present disclosure relates to an apparatus and method for diagnosing a failure, which may include a motor, an inverter for driving the motor, a phase current sensor for respectively detecting a phase current supplied to the motor from the inverter, and a controller for converting the phase current detected by the phase current sensor into a current, obtaining an average value of the current in one cycle and comparing the magnitude and angle of the average value with a reference value to determine a failure of the phase current sensor.
1 . An apparatus for diagnosing a failure of a phase current sensor, the apparatus comprising:
a motor;
an inverter configured to drive the motor;
phase current sensors respectively configured to detect phase currents of three-phase current supplied to the motor from the inverter; and
a controller configured to:
convert the phase currents detected by the phase current sensors into d-axis and q-axis currents;
calculate an average values of the d-axis and q-axis currents in one cycle;
determine a first condition maintained for a first reference time or longer, the first condition being defined such that a magnitude of the average values is greater than a first reference value;
in response to determining that the first condition is maintained for the first reference time or longer, determine a second condition maintained for a second reference time or longer, the second condition being defined such that an angle of the average values falls within reference ranges; and
in response to determining that the second condition is maintained for the second reference time or longer, determine the failure of at least one of the phase current sensors.
2 . The apparatus of claim 1 , wherein the motor is a 3-phase motor, and
wherein the phase current sensors comprise first to third phase current sensors for respectively detecting A-phase current, B-phase current and C-phase current supplied to the 3-phase motor.
3 . The apparatus of claim 1 , wherein the reference ranges comprise three ranges, each corresponding to a respective one of A-phase current, B-phase current and C-phase current.
4 . The apparatus of claim 3 , wherein one of the reference ranges for the A-phase current is 0.2 to 0.7 rad/s.
5 . The apparatus of claim 3 , wherein one of the reference ranges for the B-phase current is 2.5 to 2.8 rad/s.
6 . The apparatus of claim 3 , wherein one of the reference ranges for the C-phase current is −1.7 to −1.1 rad/s.
7 . The apparatus of claim 1 , wherein the controller is configured to:
determine that one of the A-phase current, the B-phase current and the C-phase current is less than the magnitude of the average values; and
determine the failure of at least one of the phase current sensors based on determining that one phase current is less than the magnitude of the average values.
8 . The apparatus of claim 1 , further comprising:
a space vector pulse-width modulator configured to drive the inverter; and
a current controller configured to provide phase and amplitude information to the space vector pulse-width modulator.
9 . The apparatus of claim 8 , further comprising:
a DQ converter configured to convert the phase currents detected by the phase current sensors into the d-axis and q-axis currents; and
a torque ripple remover configured to control the current controller so as to receive a current of the DQ converter and remove a torque ripple.
10 . The apparatus of claim 9 , further comprising:
a speed detector configured to detect a speed of the motor; and
a target current generator configured to compare the speed detected by the speed detector with a torque reference value, generating a target current and providing the target current to the current controller.
11 . A method for diagnosing a failure of a phase current sensor, the method comprising:
detecting phase currents of three-phase current which is supplied from an inverter to a motor by phase current sensors;
converting the detected phase currents into d-axis and q-axis currents;
calculating an average values of the d-axis and q-axis currents in one cycle;
determining a first condition maintained for a first reference time or longer, the first condition being defined such that a magnitude of the average values is greater than a first reference value;
in response to determining that the first condition is maintained for the first reference time or longer, determining a second condition maintained for a second reference time or longer, the second condition being defined such that an angle of the average values falls within reference ranges; and
in response to determining that the second condition is maintained for the second reference time or longer, determining the failure of at least one of the phase current sensors.
12 . The method of claim 11 , wherein the motor is a 3-phase motor, and
wherein the phase current sensors comprise first to third phase current sensors for respectively detecting A-phase current, B-phase current and C-phase current supplied to the 3-phase motor.
13 . The method of claim 12 , wherein the reference ranges are respectively set for the A-phase current, B-phase current and C-phase current.
14 . The method of claim 13 , wherein one of the reference ranges for the A-phase current is 0.2 to 0.7 rad/s.
15 . The method of claim 13 , wherein one of the reference ranges for the B-phase current is 2.5 to 2.8 rad/s.
16 . The method of claim 13 , wherein one of the reference ranges for the C-phase current is −1.7 to −1.1 rad/s.
17 . The method of claim 13 , further comprising:
determining that one of the A-phase current, the B-phase current and the C-phase current is less than the magnitude of the average values; and
determining the failure of at least one of the phase current sensors based on determining that one phase current is less than the magnitude of the average values.