Research On Hybrid Inverter Fed Open Winding Reluctance Motor Permanent Magnet Synchronous Motor Fault Tolerant Control

Hybrid inverter fed open winding permanent magnet synchronous motor(HI OW-PMSM)is a kind of OW-PMSM fed by a single DC source with isoltated DC bus.The inverter powered by DC source is named as main inverter(MI)and the inverter powered by large capacitor is named as compensator inverter(CI).HI OW-PMSM inherits the merits of both open winding topology and PMSM.With high efficiency,small volume,high power density,diverse voltage modulation,redundancy and other characteristics,HI OW-PMSM shows broad application prospects in electric vehicle,high speed train,ship driving etc.In driving system,the fault tolerance ability plays a critical role in the stability and safty of the system.Thus,this paper focuses on the fault tolerance control for HI OW-PMSM.The pulse width modulation(PWM)for four-switch three-phase inverter(FSTPI),the post-fault operation for HI OW-PMSM when inverters fail and the compensation capability of the CI are sudied in this paper.The paper is organized as follows:Firstly,the research background and significance of fault tolerance control for HI OW-PMSM are analyzed and summarized.The current research status of HI OW-PMSM and fault tolerance control are reviewed briefly.Secondly,the mathematic models of HI OW-PMSM are established.Flux weakening control based on MI voltage feedback is introduced by using the conception of "virtual motor".Also the vector control is introduced which gives a solid base for the subsequent research.The third part explores the PWM for FSTPI.To simplify the traditional PWM of the FSTPI,gh coordinate is introduced.The impedance model of the FSTPI is set up and the reason to cause the current imbalance for FSTPI is derived.A Unified PWM for FSTPI taking the unexpected neutral-point voltage fluctuations into account is proposed,which can guarantee the high-quality currents.Furthermore,it directly generates the switching time and removes sector identify procedure,thus the algorithm is simplified greatly.The relationships between different PWMs are also derived.Experiment has been carried out to prove the effectiveness and feasibility.In part four,the fault tolerance control for HI OW-PMSM is studied.All possible faults of the inverter are illustrated,and based on the existing OW-PMSM fault toleranc topology a new fault tolerance topologies for HI OW-PMSM is proposed.Mathematic models for different posst-fault topology are derived and given.Experiment has been carried out to prove the performance of the posst-fault topology.Finally,the compensation performance of FSTPI or SSTPI as CI has been analysed from the following respects:the motor voltage at different operating areas,the motor speed,torque and power expansion range.Finally experiment has been carried out to vertify the analysis.