| 摘要 |
A variable speed drive 1 which is configured to drive a motor 9 comprises a DC bus 4 which is operable to carry a DC bus voltage and current. The variable speed drive further comprises a DC-AC inverter 7 to convert the DC bus voltage and current into AC active power flowing in a forward direction from the variable speed drive to the motor along a conduction path 14. A method of controlling the variable speed drive comprises calculating active power flow between the variable speed drive and the motor through a component 16 positioned in the electrical conduction path. The DC-AC inverter within the variable speed drive is controlled in response to the calculated active power flow to limit active power flow in a reverse direction from the motor to the variable speed drive to a pre-determined level, thereby minimising or preventing an increase to the DC bus voltage within the variable speed drive. The motor may be used, for example, in a pump, fan, elevator or conveyor. |
