摘要 |
An AC synchronous motor, also known as a stepper motor, uses its magnetics and drive coils to produce both motion and excitation for sets of position sensing coils. Each drive phase is equipped with one or more sensing coils (80,82,86,88) which may be differentially wound, with the coils configured to act as secondaries of a linear variable differential transformer (LVDT). The primary of the so-formed LVDT is the motor drive winding (84,90). The outputs from these coils are fed to a microprocessor or DSP through an internal or external A/D converter. The microprocessor or DSP decodes the measured voltages using resolver strategies to produce a position measurement. An alternate mode of operation uses these same coils to form a variable reluctance resolver. This alternative mode of operation could be used for sensing coarse position while the motor drive is not energized. |