Research On Multilevel Power Converter For Switched Reluctance Motors System In Hybrid Electric Vehicles

In recent decades,due to the rapid consumption of fossil fuel resources,hybrid electric vehicles have received extensive attention.For hybrid electric vehicles,switched reluctance motor(SRM)has a simple and robust structure and can work in harsh environments,thus it has attracted wide attention.As a motor driving option,it is more cost-effective than permanent magnet synchronous motor(PMSM).For security critical applications,sensorless control methods and fault-tolerant schemes have been developed one after another.In addition,some a dvanced technologies for improving motor efficiency and reducing vibration in automobiles have been proposed.However,the topology of multi-functional integrated switched reluctance motor power converter for hybrid vehicle applications has not been is mature yet.Aiming at the drive requirements of SRM used in hybrid electric vehicle,a multi-level power converter is studied in this paper,which combines the advantages of traditional asymmetric half-bridge converter.Firstly,the working principle of switched reluctance motor is analyzed.Then the topology and working mode of asymmetric half-bridge circuit are studied and analyzed carefully,and the topology of multi-level power converter obtained by adding front-end circuit is given.Then,the working principle and working mode of the front-end circuit are analyzed in detail,and the excitation and demagnetization commutation process of the circuit are described.The advantages of using multi-level power converter to supply switched reluctance motor are analyzed compared with conventional power converter.According to the requirements of motor operation and power supply,the paper obtains the requirements of power converter,and then designs and chooses the main power devices used in multi-level power converter.Next,after designing the switching control method and logic of the front-end circuit and the SRM control mode under the power supply topology of the multi-level power converter,the simulation model of the multi-level power converter-switched reluctance motor is built in MATLAB,and the simulation validation is carried out when motors run in various operation states,and unique characteristics of multilevel power converter are analyzed.The driving topologies of multi-level power converter and conventional asymmetric half-bridge circuit are compared,and the characteristics of fast excitation and fast demagnetization voltage topologies of multi-level power converter are analyzed and studied.Last,an experimental platform based on power circuit and dSP ACE is built in the laboratory.The experimental verification of the designed multi-level power converter is carried out,and the results are compared with those of the conventional asymmetric half-bridge circuit structure,which proves the effectiveness o f the converter topology.