一种带方波电流注入电路的串联型 24 脉波整流器

To solve the problem of high harmonic content in the input current of the conventional series-connected 12-pulse rectifier，a series-connected 24-pulse rectifier with a square-wave current injector（SWCI）is proposed. The single-phase bridge rectifier in SWCI is connected in series in the load path，and it alternately conducts according to the polarity of the input voltage to increase the number of levels of the output current of the bridge rectifier. Then，according to the corresponding relation between the currents on AC and DC sides，the number of steps of the input current of the rectifier is increased to 24，thus realizing the effective suppression of the input current harmonics. The analysis results show that when SWCI is designed with the optimal turns ratio，the input current is improved to a standard 24-step wave，eliminating the 11th and 13th harmonics. The proposed SWCI scheme does not require any active devices，and the capacity of the auxiliary transformer in SWCI is only 1.95 % of the rectifier output power，so the proposed method has the advantages of simple circuit structure，easy implementation and low cost. To verify the correctness of the theoretical analysis，an experimental prototype with an output power of 2 kW is established. The experimental results show that the total harmonic distortion of the input current is reduced from 12.1% to 3.6% after adopting SWCI，and the harmonics of the input current are effectively reduced.