STEUERUNG FÜR BÜRSTENLOSEN GLEICHSTROMMOTOR

A method and control system to control a brushless DC motor (20) to a preferred position is provided. The advantages that accrue to a system employing the method and apparatus to control the brushless DC motor (20) to a preferred position include optimizing response time, energy usage, coil heating, and ability to hold to a fixed position. The method to control the brushless DC motor (20) to a position comprises monitoring actual position of the brushless DC motor (20), monitoring energy used by the brushless DC motor (20), and determining a commanded position of the brushless DC motor (20). A zero torque commutation method is employed to control the brushless DC motor (20) to the commanded position only when a time-rate change in the commanded position is less than a first threshold (block 94), a difference between the commanded position and actual position is less than a second threshold (block 96), and, the monitored energy used is less than a third threshold (block 98). A peak torque commutation method (block 60) is employed to control the brushless DC motor (20) to achieve the commanded position when the time-rate change in the commanded position is greater than the first threshold (block 94), the difference between the commanded position and actual position is greater than the second threshold (block 96), or the monitored energy used is greater than the third threshold (block 98).