Permanent Magnet Synchronous Generators (PMSGs) have been widely used in modern wind power system. Direct-drive permanent magnet synchronous generator (D-PMSG) has shown significant advantages for its high efficiency, reliability, and become an attractive choice for variable-speed wind power generation. A Fast, robust, efficient, smooth controling power generated by the PMSG is essential for the D-PMSG. This paper presents a mathematical model of PMSGs, and a novel Space Vector Modulation (SVM) based on constant switching frequency Direct Power Control(DPC) method and a new speed sensorless methods of the DPC-SVM control strategy are proposed. The research in this paper is verified by simulation and experiment results. It has been demonstrated that the proposed strategy can be an attractive and practical solution to PMSG system applications.