| 摘要 |
PROBLEM TO BE SOLVED: To solve problems that arise associated with convergence computation when d- and q-axis currents are determined based on only torque commands and voltage conditions in controlling IPM and problems of voltage saturation and magnetic saturation. SOLUTION: Q-axis current computation estimates from a magnetic flux table 11 a magnetic flux component corresponding to the current of a rotating coordinate system that rotates in synchronism with a field system, and an output torque computation part 13 estimates from a q-axis current and the result of the magnetic flux estimation a torque that is produced in this state of current. A torque current computation part 14 determines a q-axis current component that corrects the component of error between the estimated torque and a torque command so that the estimated torque is matched with the torque command, adds up the q-axis current component and the present q-axis current, and outputs the result as a new torque current command. An inductance table 12 calculates self-inductance on the d-axis and the q-axis when the current of the rotating coordinate system varies, and uses it for q-axis current computation. In addition, a voltage saturation prevention controlling means is included which, if the output voltage is increased and exceeds a voltage limit value, produces a demagnetization current. |
