Starting brushless D.C. motor, involves applying test current pulses, and determining phase of stator flux vector produced by test current pulse with smallest integration value of flux generating voltage

摘要

The method involves applying several voltages to the stator (11) winding by suitably controlling a switching device to determine the rotor (13) position when the rotor is at rest. It involves sequentially applying a number of test current pulses to the stator winding to produce stator flux vectors evenly distributed over 360 degrees, measuring the summation current, integrating the voltage producing the stator flux and determining the phase of the stator flux vector produced by a test current pulse with the smallest integration value of the flux generating voltage as the rotor position.