Unconventional Inter-phase Reactor Technology For Line Side Current Harmonic Suppression Of Power Frequency Rectifier

Full bridge parallel rectifiers are widely used in high power rectifying occasions because of the high reliability and high conversion efficiency of this technology;and conventional tapped inter-phase converter(TIPC)technology is an effective measure to further suppress the input current harmonics.However,there are some problems such as large conduction loss caused by tapped diode flowing through a large current level,controllable switch devices with synchronous and trigger circuits are needed in multi tap condition,and only low harmonics in rectifier input current can be suppressed.This restricts the application of this technology in the rectifier and its performance improvement.Therefore,by means of the efficient “targeting” harmonic suppression effect of low power inter-phase conversion technology,while giving full play to the original advantages of the rectifier,the unconventional inter-phase converter technology with different characteristics and its implementation method are studied.By means of theoretical analysis,simulation and experimental research,the harmonic suppression mechanism,operating conditions and circuit parameters optimization of the proposed method are studied,and focuses on the analysis of the influence of the proposed method on the input current harmonic,output voltage ripple and equivalent capacity of the rectifier.Aiming at the problem of large diode conduction loss in the traditional TIPC-2,this paper proposes a harmonic suppression method with low conduction loss.The working conditions of the method are analyzed and its three working modes are discussed.On this basis,the optimal design of the method is carried out aiming to minimize input current harmonics.Based on the optimal parameters,the complete relationships of the voltage and current of rectifier using the method is established and the main voltage and current waveforms are given.On this basis,the input current and output voltage characteristics of the rectifier are analyzed.In addition,in order to investigate the effect of the new method on the capacity of the rectifier,the equivalent capacity of all the magnetic components in the rectifier using the method and the single phase full wave rectifier circuit in the method are analyzed and calculated.The simulational and experimental results demonstrate the feasibility and effectiveness of the proposed method.Compared with traditional TIPC-2,the method can significantly reduce the diode conduction loss while allowing the rectifiers maintain the same level of THD value and ripple coefficient.Moreover,the new method has little influence on the rectifier capacity.Compared with TIPC-2,the conventional TIPC-3 can further suppress the input current harmonics.However,the tap changer tube must be controllable device,so it is necessary to add additional circuits such as synchronization,trigger and so on.In addition,TIPC-3 causes the output voltage ripple coefficient of the rectifier to be worse.For this reason,a simple uncontrolled harmonic suppression method is proposed in this paper.The working condition of the method is analyzed and its four working modes are discussed.On this basis,the optimal design of the two parameters which have an influence on the input current harmonics is carried out.Based on the optimal parameters,the complete relationships of the voltage and current of rectifier using the method is established,and the main voltage and current waveforms are given,and the input current and output voltage frequency domain characteristics of the rectifier are clarified,and the influence of this method on the equivalent capacity of the rectifier is analyzed.The simulational and experimental results demonstrate the feasibility and effectiveness of this method.Compared with conventional TIPC-3,on the basis of maintaining the same harmonic suppression ability,the proposed method significantly reduces the output voltage ripple coefficient,and has little influence on the rectifier capacity,and the circuit is more concise.An active harmonic suppression method is proposed to suppress all harmonics of the input current of the rectifier,so that the harmonics can be suppressed to the maximum extent.The harmonics suppression properties of the method are analyzed,and the selection and design process of the specific implementation are presented.The influence of this method on the capacity of rectifier and the equivalent capacity of PWM converter in the active inter-phase converter are also calculated.The results indicate that AIPC can significantly reduce the input current harmonics while maintaining the previous voltage properties of the rectifier.In addition,in order to suppress the input current harmonics and output voltage ripple of the rectifier,but also can reduce the active converter capacity,a hybrid harmonics suppression method combining the active converter and passive converter is proposed.The circulation patterns of passive and active links in the hybrid methods are analyzed;the influence laws of determinant factors of circulation synthesis ratio on input current harmonics of rectifier,active link capacity and peak current of active link are studied,and the parameter range of the optimal hybrid effect is determined based on the rationality and validity of the hybrid scheme.