Inverter control device, motor drive device, and electric power steering apparatus

1. An inverter control device comprising:

at least first and second inverters;

a current detector that detects a current flowing through a main circuit of the first inverter;

a current controller that generates a voltage command value of the first inverter on the basis of a detected current and a current command; and

a voltage command predictor that generates a voltage command value of the second inverter on the basis of a variation of the voltage command value of the first inverter.

2. The inverter control device according to claim 1 , wherein the current detector sequentially switchingly detects a current flowing through the main circuit of the first inverter and a current flowing through the main circuit of the second inverter,

the current controller generates the voltage command value of the first inverter on the basis of the detected current and a predetermined current command during a current detection period of the first inverter, and

the voltage command predictor generates the voltage command value of the second inverter during the current detection period of the first inverter by adding a variation of the voltage command value of the first inverter to the previous voltage command value of the second inverter.

3. The inverter control device according to claim 2 , wherein the current controller generates a voltage command value of the second inverter on the basis of the detected current and a predetermined current command during a current detection period of the second inverter, and

the voltage command predictor generates the voltage command value of the first inverter during the current detection period of the second inverter by adding a variation of the voltage command value of the second inverter to the previous voltage command value of the first inverter.

4. The inverter control device according to claim 1 , wherein the current detector detects a DC bus current flowing to a DC bus of the first inverter.

5. The inverter control device according to claim 1 , wherein the current detector detects a current flowing between a lower or upper arm of each phase of the first inverter and a DC bus.

6. The inverter control device according to claim 1 , wherein the current detector detects a current flowing to a three-phase AC output line of the first inverter.

7. The inverter control device according to claim 1 , further comprising an abnormality detector that detects an abnormality in the first inverter on the basis of a current detected by the current detector.

8. The inverter control device according to claim 7 , wherein the abnormality detector stops (turns off) switching of all of upper and lower arms of each phase of the first inverter in a case where a DC bus current of the first inverter detected when all of the lower arms of each phase of the first inverter are set to ON is larger than a predetermined threshold value.

9. The inverter control device according to claim 7 , wherein the abnormality detector stops (turns off) switching of all of the upper and lower arms of each phase of the first inverter in a case where a three-phase AC current of the first inverter is larger than a predetermined threshold value.

10. A motor drive device comprising:

the inverter control device according to claim 1 ; and

a motor having

a first coil connected to the first inverter;

a second coil connected to the second inverter;

a stator where the first and second coils are wound.

11. An electric power steering apparatus mounted with the motor drive device according to claim 10 .