基于电力电子变压器的串联型12脉波整流器

In order to solve the problem of large volume and high weight of phase-shifting transformer in series multi-pulse rectifier, a series-connected 12-pulse rectifier based on power electronic transformer was studied. The rectifier is composed of an AC-AC converter and a high frequency multi-pulse rectifier. The working principle of the AC-AC converter was analyzed, its control strategy was designed, and the quantitative relationship between the input and output voltages of AC-AC converter was obtained. The phase shifting transformer was designed, and according to its structure, the mathematical relationship between the input voltage and the input voltage of the rectifier bridge was obtained; using the switching function method, the conduction mode of two three-phase diode rectifier bridges was analyzed, and the relationship between the input voltage of the power electronic converter and the output voltage of the rectifier was obtained. The concept of equivalent resistance was introduced, and the analytical model of rectifier was established, and the expressions of input current and input power factor of power electronic transformer were obtained. The simulation and experimental results show that the volume and weight of the main transformer are reduced by two thirds, the THD value of the input current of the power electronic transformer is about 6.5%, and the load voltage and current keep constant.