Research On Scheme Of Zero-Sequence Currents Suppression For Open-end Winding Induction Motor With Common DC Bus

In the context of global energy crisis and environmental pollution,energy conservation,emission reduction,new energy development and sustainable development have become the focus of the current countries.The rapid development of China's social economy and the further demand for the construction of"two-oriented society" have greatly promoted the development of electric traction technology and new energy generation technology.Among them,the research on the performance of the motor control system,which is an important link,is getting deeper and deeper.Since the birth of motor,after more than a century of research and development,has formed a relatively mature theory of motor and control technology,but with the rapid development of modern industry and environmental energy transformation,in the form of increasingly complex operating environment on the motor and the requirements of the converter drive technology.In this environment,the research of new motor drive topology and control strategy has attracted wide attention from the academia and industry.Open a winding motor system as a new type of motor driven topology form,began to be widely fan's attention in recent years.Both ends of winding motor stator winding can be seen,which can realize dual-terminal drive mode with double inverter.Compared with the traditional single-ended power supply system,the advantages of the dual inverter open winding system are mainly reflected in the diversity of power supply.Flexibility of control mode;The redundancy and fault tolerance of the switch tube fault;High voltage output capability;Multi-level voltage output effect,etc.The induction motor has the advantages of simple structure,reliable operation,low maintenance cost and mature industrial chain.It is the main force in the field of electric power transmission.The advantage of asynchronous motor drive system is further strengthened based on the variable frequency speed regulation topology of asynchronous motor.Open winding topology itself,has two kinds of common bus and independent busbar connection mode,the independent need two set of isolated dc power bus structure,increase the complexity and cost of the hardware system design of driving system,and the total bus structure is no need for additional power supply design,get more extensive application in the frequency control of motor speed.Existing of zero sequence circulation pathway in common bus topology,which makes for PWM modulation,nonlinear inverter and zero sequence zero sequence voltage which is formed by the counter electromotive force will produce zero sequence circulation,cause additional loss,lower efficiency and system capacity,increase system aging.Therefore,the difficulty in controlling the common bus structure is zero sequence circulation suppression.The control of zero sequence voltage and zero sequence current of open winding system is usually realized by controlling the common mode voltage of inverter.Based on this,based on the research of the common-mode voltage suppression modulation algorithm for the inverter,a common-mode voltage controlled space vector PWM scheme is proposed for the suppression of the zero-sequence current in the open-winding asynchronous motor with common DC bus.The control of zero sequence current is realized by the active control of common mode voltage of single inverter.At the same time,the space vector modulation scheme can better suppress the inverter to the ground common mode voltage,which is beneficial to the suppression of the motor shaft current.In this paper,through building a common dc bus driving winding asynchronous motor simulation and experimental platform,the study of single inverter common-mode voltage suppression strategies,and proposed the feasibility and effectiveness of zero sequence current control strategy has carried on the simulation and experimental validation.