Method and system for controlling the start of a permanent magnet machine are provided. The method allows to assign a parameter value indicative of an estimated initial rotor position of the machine. The method further allows to energize the machine with a level of current being sufficiently high to start rotor motion in a desired direction in the event the initial rotor position estimate is sufficiently close to the actual rotor position of the machine. A sensing action allows to sense whether any incremental changes in rotor position occur in response to the energizing action. In the event no changes in rotor position are sensed, the method allows to incrementally adjust the estimated rotor position by a first set of angular values until changes in rotor position are sensed. In the event changes in rotor position are sensed, the method allows to provide a rotor alignment signal as rotor motion continues. The alignment signal allows to align the estimated rotor position relative to the actual rotor position. This alignment action allows for operating the machine over a wide speed range.
This invention was made with U.S. Government support through Definitized Subcontract C-HEV-5A under MRI/CHRYSLER Subcontract No. ZAN-6-16334-01 under PRIME CONTRACT NO. DE-AC36-83CH10093 awarded by the Department of Energy, and in accordance with the terms set forth in said contracts, the U.S. Government may have certain rights in the invention.