Sterowanie zasilaniem silnika bezszczotkowego w napędzie łodzi motorowej

This paper describes electronic commutator, which determines current rotor position using signals produced by additional windings placed in the motor stator. On account of drive specific properties, the motor shaft may perform two steps contrary to the required direction during motor start-up. The system consists of transistor bridge which supplies voltage to different motor windings in accordance with commutation scheme. The bridge is microprocessor-controlled. Control signals input to the microprocessor are rotor position and supply current. The control has been divided into two stages: start-up and normal operation. The start-up is performed on the basis of start-up commutation sequence recorded in microprocessor memory (if rotor is stopped, then there is no information as to its position). When the motor shaft starts, this commutation sequence may cause shaft movement in direction opposite to the required direction and only afterwards the proper rotation (i.e. in the desired direction) is initiated. During normal operation, emfs induced in motor additional windings are used as control signals. On the basis of these additional windings signals, six operational phases have been defined, each corresponding to single rotor position. Bridge transistor conditions have been defined for each phase. Microprocessor is responsible for controlling bridge transistors as well as motor input current. If current limit is exceeded, then transistor conducting time is decreased.