| 摘要 |
PURPOSE:To enable improvement of an adhesion performance by preventing a sudden change of an inverter frequency even at the time of an abnormal operation of a vehicle and by utilizing a drooping characteristic which an induc tion motor has. CONSTITUTION:A specified number of revolutions is selected as a rotor frequency from the numbers of revolutions obtained by revolution detectors 51 to 54 and it is stored as history data in a ring buffer 11. Based on the stored history data, rotor frequency difference data 67 are generated and data contained in an upper limit value C1 and a lower limit value C2 are generated as rotor frequency difference data 71. Then, a vehicle acceleration alpha is computed by preestimation from these data in a vehicle acceleration computing part 2, the rotor frequency is calculated from this vehicle acceleration in a rotor frequency calculating part 3, an inverter frequency 80 is generated from this rotor frequency and a command slip frequency 79 and thereby each of induction motors 41 to 44 is controlled. The upper limit value C1 and lower limit value C2 are corrected in accordance with an operation command 74 and the inverter frequency 80. |
