Research On Five-Phase Motor Control System Of Current Source Inverter Based On SiC Device

The space field is the strategic location of each country’s layout,and the level of space science and technology is an important indicator to measure the country’s comprehensive scientific and technological strength.Servo control system is the core component of spacecraft,which requires high reliability and fault tolerance.At present,multi-phase motor servo system has become a research hotspot because of its excellent fault-tolerant ability.Current source multi-phase motor servo system based on wide bandgap device has the advantages of short-circuit fault-tolerant ability and high reliability.However,the current research focus in the field of multi-phase motor control is voltage source topology.The theoretical system of multi-phase motor control system based on current source inverter is still not perfect.Further research is needed in the design of polyphase current source servo motor control system,faulttolerant control and the application characteristics of power devices under current source inverter topology.In this paper,the current source five phase permanent magnet synchronous motor control system is used as the research object.Firstly,the basic theory of the fivephase permanent magnet synchronous motor and the current source controller is introduced,and the current source five phase half bridge inverter topology suitable for the five-phase control system is analyzed.At the same time,the working mode of the inverter topology,the influence of the key parameters of the topology on the system and the development of the space current vector diagram under the topology are discussed It provides theoretical basis for the design of control system parameters,the research of control strategy,the research of fault tolerance strategy and the research of device application characteristics.Secondly,three control strategies are proposed for the current source five phase motor control system,which are two adjacent vector modulation control strategy of double loop structure,two adjacent four vector modulation control strategy of double loop structure and four adjacent four vector modulation control strategy of four-loop structure.At the same time,the design of control system and the research of resonance are carried out,and the performance of three control strategies is simulated and analyzed,among which the four-loop structure adjacent four vector modulation control strategy has the best phase current quality.Then,the influence of superimposed flow area on the system performance is studied,and the compensation measures of superimposed flow area are given.The results show that the system performance does not decline obviously under the short time and long time of superimposed flow area,the system performance deteriorates seriously under the long time of superimposed flow area,and the compensation measures of superimposed flow area can improve the system performance under the long time of superimposed flow area.Thirdly,the open circuit of single-phase winding,two-phase winding,singlephase winding and inverter topology single-phase bridge arm and two-phase bridge arm are analyzed theoretically.At the same time,the fault-tolerant strategies under each fault are proposed based on five-phase half bridge current source inverter topology.The simulation verifies the proposed fault-tolerant strategies and evaluates the system performance.Finally,The application characteristics of the wide bandgap device Si C MOSFET in the current source inverter topology are studied,including the influence of high frequency on the system,the influence of stray inductance at high switching rate,etc.,the simulation analysis of switching off voltage spikes,crosstalk phenomenon,etc.,and the in-depth study of MOSFET switching loss of power devices in the application of superimposed current area.A loss evaluation method is proposed,and the heat dissipation structure is studied based on the loss evaluation.