Patent ID: 7791302
Filing Date: 2010-09-07
Classification: G01R,H02P

Abstract:
1. A method for measuring a current (IMOT) flowing through a motor, wherein a power switching section, which supplies the motor with electrical power, is controlled by a control unit via a pulse-width modulation signal, which has a switching cycle having a pulse section with a pulse width, and has a pause section with a pause width, wherein, in order to determine the motor current, one and only one measured value which represents the motor current is sampled in each switching cycle, whose sampling time is defined by a trigger signal from the control unit, comprising: varying the trigger signal for the control unit freely on a user-specific basis such that the sampling time is placed in a center of a time of the longer of the two cycle sections to compensate for delay time errors; determining the current direction of the motor current by taking into account the drive direction of the power switching section, wherein the determined motor current value is converted directly, by multiplication by +1 or −1, depending on the respective drive direction of the power switching section, and the sampling of the analog value in the center of a current-flow cycle, to the signed mean value of the motor current.