| 摘要 |
<p>An electronically commutated direct current machine comprising a rotor and a stator has a stator winding arrangement that can be supplied, via a full bridge circuit (78), with current from a direct current source (73, 74). A commutation arrangement (49, 50, 52, 54) is provided for commutating the semiconductor switches (1) (80 through 85) and is embodied in order, as a function of at least the position of the rotor (110), in a first bridge arm to switch on only one semiconductor switch in each case, and in a second bridge arm, controlled by a switching signal (PWM2), alternatingly to switch on and off a semiconductor switch associated with the switched-on semiconductor switch of the first bridge arm. Also provided is an arrangement for generating a switching definition signal (PWM1) which, by way of its magnitude, controls the pulse duty factor for the alternating switching on and off of the semiconductor switch associated with the first bridge arm. Also present is a current limiting arrangement (131, 161), controllable by means of a current target value signal (PWM_I+; PWM_I-), which, when a current specified by the current target value signal is reached in the direct current machine, modifies the switching definition signal in such a way that the current in the direct current machine becomes no greater than a limiting current that is specified by the current target value signal.</p> |
