| 摘要 |
The method described allows the speed of rotation of a DC motor having separate exitation to be detected utilising only electrical quantities of the motor and the associated control circuitry. It provides for the detection of the armature current (Ia) and exitation current (Ie), the average armature voltage (VM) and a quantity proportional to the exitation flux ( phi ), and the formation of the product between the armature current (Ia) and the resistance (Ra) of the armature circuit to obtain the ohmic voltage drop (VR) across the armature circuit, taking the difference between the average armature voltage (VM) and the voltage drop (VR) across the armature circuit and forming the ratio between the said difference and the exitation flux ( phi ) whereby to obtain a quantity proportional to the speed of rotation (n) of the motor. For application to electric traction vehicles the exitation current (Ie) is assumed as the quantity proportional to the exitation flux. A circuit system for putting the above indicated method into practice is also described. <IMAGE> |
