Patent ID: 7868573
Filing Date: 2011-01-11
Classification: H02K,H02P

Abstract:
1. An electrical machine having a stator with a plurality of slots and a drive circuit for interfacing the electrical machine to an alternating current (ac) network, the drive circuit comprising: first and second network rectifiers/inverters connected to the ac network in parallel; a first pulse width modulation (PWM) rectifier/inverter connected to the first network rectifier/inverter through a first dc link; a second PWM rectifier/inverter connected to the second network rectifier/inverter through a second dc link; a first two-layer stator winding having a plurality of stator coils connected to the first PWM rectifier/inverter; and a second two-layer stator winding having a plurality of stator coils connected to the second PWM rectifier/inverter; wherein the stator coils of the first stator winding and the stator coils of the second stator winding are interconnected such that, in use, a vector sum of voltages across the stator coils in the first stator winding is substantially equal to a vector sum of voltages across the stator coils in the second stator winding; and wherein the stator coils of the first stator winding are interconnected according to the following formula: the stator coil in pole N, slot X is connected to the stator coils in pole S, slot X+1, where N is the number of any North pole, where S is the number of the next South pole after pole N in a connection sequence, and where X is the connection sequence number of the first stator coil within a given set within the North pole.