Phase current reconstruction using single current sensor (PCRSS) in conventional brushless DC motors can be used for the purposes of cost reduction and hardware imbalance elimination, etc. In this paper, the phase currents with the unipolar PWM modulation are reconstructed successfully. In particular, an algorithm of reconstructing the current of non-conducting phase is proposed for the first time. Moreover, the effect of freewheeling current is considered in detail. The accuracy of the proposed PCRSS with unipolar PWM is verified by the experiments.