Research On Model Predictive Torque Control Of PMSM Driven By Three-Phase Eight-Switch Inverter

SinceHoltz,a German scholar,first proposed a Neutral-Point-Clamped(NPC)three-level inverter circuit in 1970 s,the research on NPC inverter circuits has emerged one after another.Among them,there are so many switching devices applied in the three-level circuit that may increase the probability of various failures and affect system reliability.What's more,it may lead the system cease operation.In consequence,there are crows of scholar at home and abroad pay close attention to the fault-tolerant control of three-level inverters.Many scholars have been conducted signification research on the fault-tolerant topologies of ESTPI(Eight-Switch Three-Phase Inverter)topology and three-phase sixteen-switch inverter fault-tolerant topology for years.ESTPI,having simpler structure and lower cost,has drawn more attention and study.Under the rapid development of material technology,Permanent Magnet Synchronous Motor(PMSM),which has low manufacturing cost,simple structure and good control performance,has drown much attention in the field of electric drive.At the time that science and technology is rapidly developing,scholars' study towards PMSM has been focused on the control circuit and control strategy.The modern control,benefit by its advanced and efficient control,has been extensive applied in the motor field,which including Vector Control(VC),adaptive control,Sliding Model Control(SMC),and Active Disturbance Rejection Control(ADRC).Finite Control Set Model Predictive Control(FCS-MPC),being an optimizing control method,has become the pointresearch object in recent years.The FCS-MPC method can be divided into two types: Model Predictive Current Control(MPCC)which predict the current,and Model Predictive Torque Control(MPTC)which predict the torque.In this dissertation,the control strategy of MPTC is applied in ESTPI diven PMSM system.This dissertation will be studied in the following sections:(1)Comparing and analyzing different control strategies of PMSM and different fault tolerance control strategy of three-phase inverters,then briefly introducing the basic mathematical model of PMSM,the transformation method between each coordinate and the basic principle of MPTC control,which aims to provide important teoretical basis for subsequent research.(2)Designing an ADRC speed regulator based on the inverse hyperbolic sine function,which is applied to replace of the traditional PI speed regulator,is used to control the speed and enhance the control performance and robustness of the ESTPI-driven PMSM system.The Model Reference Adaptive System(MARS)observer,taking the place of the traditional PI speed observer,isbuilt to track and observe the speed information and realize the speed sensorless control of the PMSM system.(3)Analysising the key question of SMC,in general,the sliding mode control ratein Sliding Model Observer(SMO)may exert influence on control system.To address this problem,designing the sliding mode flux observerby improving the approach rate in MPTC of PMSM system,and constructing ESTPI driven PMSM MPTC control system based on the sliding mode flux observer.