The duty cycle of the AC terminal voltage of the three-stage cascaded H-bridge rectifier was derived and the working state of the circuit was analyzed in this study. Then, the ripple formula of the inductor current under each working condition was derived. On this basis, the curve of the inductor ripple current and the varia- tion of the inductor magnetic loss in half of the mains cycle were obtained. Comparing the single-stage H-bridge rectifier and the single-stage triple-frequency H-bridge rectifier, it can be seen that the magnetic loss charac- teristic of the three-stage CHBR inductor was different from that of the single-stage H-bridge rectifier, and the frequency of the single-stage H-bridge rectifier was increased to Triple times also does not reflect the magnetic loss characteristics of the three-stage CHBR. By calculation, the total core loss of the three-stage CHBR induc- tor is only 0.05 times that of the single-stage H-bridge rectifier. Finally, the correctness of the analyzed theory was proved by experiments.