Reduction of Cogging Torque in Dual Rotor Permanent Magnet Generator for Direct Coupled Wind Energy Systems

Table 1

Cogging torque values obtained before and after applying the different cogging torque reduction methods individually.

S. number	Cogging torque; reduction method	Before applying cogging torque reduction method			After applying cogging torque reduction method
1	Changing slot opening width	(mm)	(mm)	(Nm)	(mm)	(mm)	(Nm)
		1.5	2.5	1.818	1.5	1.35	0.889
2	Changing magnet pole arc width	(mm)	(mm)	(Nm)	(mm)	(mm)	(Nm)
		10.68	20.32	1.818	8.99	20.32	1.2
3	Shifting of slot openings			(Nm)			(Nm)
		Not shifted		1.818	Shifted anticlockwise by 6.01 mm	Shifted clockwise by 10.11 mm	0.612