Dual space vector pulse width modulation（SVPWM）is the easiest modulation strategy to implement in the six-phase synchronous wind power generator digital control system，and the current ripple is an important index to weigh the current waveform quality and the generator height property of a modulation strategy.This paper analyzes the mapping property of the dual voltage vector used in the space vector decoupling coordinates，and points out the principle of the current ripple.The mathematical expressions of the harmonic distortion factor and current ripple in a single fundamental period are derived using the numerical analysis method.The reactor parameter is obtained by the backward-deduction method with the information of maximum current ripple，which is simple to implement and does not need complex simulation analysis.The validity of the deduction process and reactor selection is confirmed by comparison of deduction results，simulation results and experimental results.