基于相移变压器的双桥整流器

为了消除电源电流中的特定谐波,首先采用相移变压器的双桥12脉冲整流器拓朴结构,用相移变压器相互抵消原理消除其线电流iA中的5、7、17和19次等谐波,同时采用选择谐波消除调制(SHE-PWM)法消除iA中所包含的11、13次谐波。SHE-PWM非线性方程组中各种情况下全部开关角度用数值计算法解出。用MATLAB软件和DSP320LF2407硬件平台仿真和实验研究该整流器的结果表明,这种整流器的调制电流iA<23次的谐波全部消除,线电压所有谐波失真仅1.49%,符合国际上对电能质量谐波失真的最严格的要求。

Dual Bridge Rectifier Based on Phase Shifting Transformer

This paper puts forward a 12-Pulse dual bridge rectifier with phase shifting transformer. The 12-pulse rectifier is often used as a front end for current source inverter (CSI) fed drives. For the 12-pulse rectifier, the line current i_A does not contain 5~ th , 7~ th , 17~ th or 19~ th harmonics due to adopt phase shifting transformer, and thus the line current waveform is improved and its THD reduced in comparison to those in the common SCR rectifier. The transformer for the 12-pulse rectifier has two secondary windings with a 30 phase shift between them. In order to eliminate 11~ th and 13~ th harmonics in the line current i_A, this paper introduce the thought of Selected Harmonics Elimination(SHE)technology and analyze switching states during SHE-PWM method concretely. In order to produce the required fundamental voltage while at the same time not generate the selective harmonics, deduce the mathematic model of SHE-PWM via its principle analysis, which is a nonlinear transcendent equations. Moreover, a numerical iteration algorithm namely Newton-Raphson is introduced to solve the nonlinear transcendent. The basic thought of Newton-Raphson iteration algorithm is to transfer the nonlinear equations to linear equations which can be solved by Gauss algorithm and then approximate to the real solution of the nonlinear transcendent equations in step. The solving algorithm for the nonlinear transcendent equations can converge to the real solution with arbitrary precise in theory, which can be eligible to the requirement of practice. It is,at last, investigated with simulation and experiment via MATLAB/SIMULINK software and DSP320LF2407 flat roof, the results confirm that the topology of the rectifier eliminated all harmonics below 23~ th and it's total harmonics distortion of line-line voltage only is 1.49. The THD completely conform to the international standard of harmonic constraint, and the experiment also matches the results.