| 摘要 |
A method for controlling brake resistors and a brake chopper, the number of brake resistors (73, 75, 77) being two or more and the brake resistors being connected in series with switches (72, 74, 76) to be controlled, the series connection being connected between a positive and a negative rail (U dc+ , U dc- ) of a DC voltage intermediate circuit, the method comprising the step of determining a magnitude for a voltage (U dc ) of the DC intermediate circuit; and determining a first voltage limit (U lim1 ) and a second voltage limit (U lim2 ). The method further comprises the steps of switching brake resistors to the intermediate circuit in a periodically alternating manner, each switch being switched during a switching period and the on-period of each switch in a switching period being responsive to the magnitude of the voltage in the DC voltage intermediate circuit when the voltage is above the first predetermined limit and below the second predetermined limit. |
