基于直流侧混合电压谐波注入的低谐波串联36脉波整流器

A Series 36-Pulse Rectifier Operating in Low Harmonic State Based on Hybrid Voltage Harmonic Injection at DC Side

为满足整流器高电压输出和提升串联12脉波整流器谐波抑制能力,提出一种使用直流侧混合脉波倍增技术的低谐波串联36脉波整流器。基于隔离型串联12脉波整流器,在其直流侧设置混合电压谐波注入电路且负载端并联滤波电容,可同时抑制交、直流侧谐波,实现低谐波运行。混合谐波注入电路参与调制两个整流桥间电流和电压波形,最终使交流侧输入电压阶梯数由12提升至36。该文分析所提36脉波整流器工作机理,设计注入变压器最优电压比、功率管IGBT导通角及其控制电路,研究正常状态下和IGBT故障下整流器的运行特性,并使用硬件在环(HIL)测试系统验证了理论分析的正确性。实验结果表明,所提整流器器件利用率高、谐波含量低,IGBT故障下具备鲁棒性强、输出电压增益高的特点,可应用于高电压、高功率变流场合。

High-power multi-pulse rectifiers are often used in HVDC,adjustable speed motors,arc furnaces,electric vehicle charging modules,aircraft power supply,radar power supply,and marine power supply,but a large number of nonlinear harmonic source devices cause serious harmonic pollution to the public power grid.The traditional 12-pulse rectifier has the advantages of a simple structure and strong robustness.However,a large number of harmonics exist at the grid and DC sides,which needs to meet the relevant applicable industry harmonics standards.It often needs to be improved with a harmonic suppression scheme to meet the requirements of different industrial occasions.Therefore,considering the characteristics of passive and active harmonic suppression methods,a low harmonic series 36-pulse rectifier based on DC side hybrid pulse multiplication technology is proposed,which optimizes system structure,improves device utilization,enhances system stability,and reduces power distortion.By setting one additional hybrid voltage harmonic injection circuit(HVHIC)and capacitors,AC and DC power quality can be improved.Firstly,the working principle of the rectifier with HVHIC is analyzed based on the proposed topology,and the formation of the input phase voltage 36-step wave at AC side is revealed.Considering the diode voltage drop,the theoretical values of the AC input voltage step wave are derived.Secondly,with the aim of the lowest voltage distortion at AC side,the IGBT turn-on angle and the injection transformer turn ratio are calculated.In addition,the corresponding IGBT control circuit is designed based on the operating mechanism of the rectifier and the theoretical value of the optimal IGBT on-angle.Then,considering the filter inductances at the source side,the voltage and current distortion characteristics of the rectifier at AC and DC sides are analyzed.Combined with the IGBT state of high failure rate,the harmonic suppression ability of the IGBT state of short and open circuits is analyzed.Finally,Simulink and the Starsim-based hardware-in-the-loop(HIL)platform verify the theoretical analysis results.After comparing different harmonic suppression schemes,the operating characteristics of the proposed rectifier are evaluated,and the reasons for its application in relevant industrial applications are given.The following conclusions can be drawn from the simulation and experimental analysis:(1)The proposed rectifier has input inductance,and the total harmonic distortion(THD)value(3.28%)of the input current is lower than the input voltage THD value(5.07%).Therefore,the optimal ratio of the injection transformer is designed to reduce the input voltage THD value,which can improve the power quality at AC side,while the parallel capacitors at DC side make the output waveform stable.Accordingly,the harmonic suppression effect is significant on the whole.It is suitable for high voltage gain and high-power AC-DC situations requiring electrical isolation.(2)The injection transformer in HVHIC has a simpler structure,only two diodes are used,and there is no need to install additional taps,which improves the economy and intensity of the system.(3)The IGBT control circuit uses phase locked loop(PLL)to realize phase synchronization of the gate trigger circuit,and the control process optimizes logic operation.It has the advantages of stability and efficiency.(4)When IGBT fails,the proposed rectifier can operate in the low harmonic state in a completely passive state with strong robustness.However,IGBT short circuit faults should be avoided as far as possible.