Brushless DC drive operation during phase commutation under various switching patterns

The paper deals with the operation of a brushless DC drive during the phase commutation. At first, the various switching patterns that can be used to command the inverter are identified. It is demonstrated that the switching patterns are a combination of two basic commutation modes. For each mode, the current transients during the phase commutation are determined as well as two significant commutation-related quantities, namely the decay angle of the current in the outgoing phase and the maximum current excursion in the non-commutating phase. The results obtained for the two modes are then compared, showing that each switching pattern gives a brushless DC drive specific properties.