Control of direct-prive permanent-magnet wind power system connected to grid

This paper discusses a control strategy of direct-drive permanent magnet wind power system, and proposes back-to-back PWM converter control method that PWM technology is employed both in generator-side and grid-side. The system consists of permanent magnet synchronous generator (PMSG), PWM rectifier in generator-side, intermediate DC circuit, and PWM inverter in grid-side. DC voltage control is used as external loop while current control as internal loop to maintain DC voltage a constant, the active power is controlled by q-axis current whereas the reactive power is controlled by the d-axis current in generator-side ; In grid-side, active power and reactive power are controlled respectively as external loop. Experimental tests are carried out to verify the feasibility of the system.