Space vector modulation (SVM) schemes with leakage current mitigation capability for current‐source inverters (CSIs) in transformerless photovoltaic (PV) systems have not been well explored yet. In this study, the advantage of a special SVM scheme, called active zero‐state SVM (AZS‐SVM), on suppressing high‐order harmonics in the common‐mode voltage (CMV) is revealed and theoretically analysed, since the high‐frequency components in the CMV have decisive impacts on the generated leakage current. A five‐segment sequence is proposed for AZS‐SVM applied for CSIs. Both simulation and experiments are conducted on a (2.5 kW/208 V/6.94 A) grid‐connected three‐phase CSI, which validates the effectiveness of the designed AZS‐SVM to mitigate the CMV high‐order harmonics when compared to that by conventional SVM under different operating conditions.