Control principles of current source inverter DC terminal voltage in direct-drive wind power generation system

This paper studied the control of current source inverter (CSI) used in direct-drive wind power generation system, where CSI serves as the actuator of the control and optimization of the system besides the grid inverter. This function of CSI is realized through the control of CSI dc terminal voltage V_dc. Two factors which exert restrictions on the control of V_dc were analyzed. The first one is the limits caused by the grid-connected transformer primary voltage on achievable V_dc range. The second one is the restriction on practical V_dc range for the continuity of dc-link current t_d. According to analysis results, the control principles of V_dc were derived.