| 摘要 |
Control device (30) and method for controlling an AC motor (18) by means of a motor control unit (19). The control device (30) includes an AFE unit (33) arranged in parallel with the rectifier unit (12), which AFE unit (33) is arranged for, under normal operation, to work as an active filter and inject super-harmonic current components opposite of the ones generated by the rectifier unit (12) to counteract the current distortion, seen from the grid side. When the motor control unit (19) is running regenerative, the AFE unit (33) will work as a 4-quadrant converter and supply energy back to the supply grid (13). Advantages of the invention are reduced physical size, lower cost and improved efficiency compared to existing solutions of motor drive with frequency converters in weak grids, where the motor drive must handle regenerative operation. |
