| 摘要 |
PURPOSE: To lessen the number of compensators to be installed for preventing the troubles in controlling which are caused by an on-delay of a three-phase inverter when the inverter drives an ac motor. CONSTITUTION: A three-phase/two-phase converter 31 converts three-phase current actual values output from a PWM inverter 4 into a d-axis current actual value ID and a q-axis current actual value IQ which cross at right angles. A d-axis current regulator 34 determines a d-axis voltage command value VD* from the deviation of the d-axis current actual value ID from the current command value ID*. In a similar manner, a q-axis current regulator 35 determines a control signal from the deviation of the q-axis current actual value IQ from the current command value IQ*. Only the q axis is provided with a q-axis compensator 36 and a q-axis compensating signal Vc output from the q-axis compensator 36 and the control signal output from the q-axis current regulator 36 are added by a q-axis adder 38 and the adding result becomes a q-axis voltage command value VQ*. The d-axis voltage command value VQ* and the q-axis voltage command value VQ* are returned to a three-phase ac coordinate system again by a two phase/three-phase converter 37 and the PWM inverter 4 is controlled on those signals. |
