Research On Control Strategy Of Dual Inverter Open-end Winding Induction Motor Drive With Common Mode Connected Dc Buses

At present,the electric drive system of new energy vehicles mostly adopts the threephase two-level inverter drive topology structure in general industrial frequency conversion and speed regulation occasions,which has poor voltage output capacity,insufficient adaptability to the speed regulation range,and lack of fault-tolerant operation ability.It is difficult to meet the technical needs of high-quality electric drive systems.The dual-inverter open-winding topology,as a new type of variable frequency drive solution,not only has multi-level characteristics and higher voltage output capability,but also has strong fault-tolerant operation capability.However,as far as the two open-winding topologies of common bus and independent bus are studied,it is still difficult to meet the needs of new energy vehicle applications: The open winding topology scheme of common bus loses the flexibility of power supply configuration,and it is difficult to meet the demand of voltage optimization configuration for mixed energy storage and wide speed regulation range;and the independent busbar open winding topology has high-frequency voltage ripple between the two DC buses,which causes safety,shaft current,electromagnetic interference,etc,and the voltage output capacity is limited during the fault-tolerant operation.In view of this,this paper studies open-end winding drive topology with common mode connected DC buses which can combine the advantages of the two,and studies its key control algorithm in combination with a floating bridge hybrid open winding asynchronous motor drive system.The main research work is summarized as follows:1.Based on the analysis of the zero-sequence loop of open-end winding drive topology with common mode connected DC buses,the zero-sequence current model is established,the adjacent four-vector modulation strategy is studied,and the zerosequence current closed loop based on the proportional resonance regulator is designed.2.Based on the analysis of the influence factors of floating bridge capacitance voltage change and capacitance neutral point potential change,the control model of capacitance voltage and neutral point potential is established,and the capacitance voltage control scheme based on active power control and the capacitance neutral point potential control scheme based on zero sequence current control are designed.3.The decomposition scheme of the active and reactive components of the stator voltage of the motor is studied.On this basis,the optimal distribution scheme of the active and reactive power of the motor between the two inverters and the improvement of the operation range and load capacity of the motor are studied.Finally,the control strategy is simulated and verified in MATLAB and experimental platform.