High-performance Model Predictive Control And Fault-tolerant Application Research For Dual Three-phase Permanent Magnet Motor

Multiphase permanent magnet motors have become the first choice for advanced motor systems due to their high power density,high efficiency,and excellent fault tolerance advantages.They are widely used in aerospace,ship propulsion,and new energy vehicles.It is meaningful to study the control strategy of a high-performance multiphase permanent magnet motor,analyze the mechanism of the control system,carry out theoretical and experimental research,and provide technical support for highdemand field applications.With the advantages of fast dynamic response,multiobjective solid constraint ability,and simple structure,model predictive control(MPC)has gradually become the mainstream algorithm in motor control.However,the existing multiphase motor MPC still has problems such as large torque ripple,large harmonic current,and poor fault tolerance.The dual three-phase permanent magnet motor is taken as the research object in this thesis.The high-performance MPC strategy is studied,further improving the theoretical research of the dual three-phase permanent magnet motor and effectively improving the steady-state performance and fault tolerance.The research content of this thesis involves the expansion and simplification of the control set,multi-space closed-loop MPC,and model predictive fault-tolerant control.The research results of the thesis mainly include:1)The modeling method of a dual three-phase permanent magnet motor is studied.The mathematical models in natural,stationary,and rotating coordinate systems are established based on the vector space decoupling theory.The voltage vector generated by the six-phase voltage source inverter is explored,and the classical model predictive current control of the dual three-phase permanent magnet motor is introduced.2)Analyze the characteristics of voltage vector,construct virtual voltage vector control set,eliminate harmonic space vector,suppress harmonic current,reduce torque and flux ripple;the virtual voltage vector control set is extended to increase the distribution density of the voltage vector,improve the system performance.Simplify the process of evaluating voltage vectors by the MPC algorithm,reduce the execution time of the algorithm,and ensure that more voltage vectors are evaluated without increasing the computational burden.3)The principle of duty cycle based MPC is analyzed.According to the relationship between the cost function and the duty cycle calculation,the geometric duty cycle calculation method is proposed to improve the control accuracy of MPC under a single voltage vector.The virtual voltage vector of harmonic space is constructed,and the harmonic space MPC structure is designed to complete the full closed-loop MPC of fundamental and harmonic space and reduce the harmonic current caused by nonlinear factors.The multi-virtual voltage vector modulation technology is used to expand the voltage vector modulation range,and finally,the full-space closed-loop continuous MPC structure is realized,which significantly improves the operating performance of the dual three-phase permanent magnet motor MPC.4)The fault-tolerant MPC strategy is studied to cope with the open-circuit fault situation.The voltage vector distribution based on the reduced dimension decoupling matrix is deduced,and the fault prediction model is established.The virtual voltage vector control set is reconstructed to eliminate the harmonic voltage vector after the fault.A fault-tolerant MPC based on virtual zero vector compensation is proposed to realize the closed-loop control of harmonic space in post-fault conditions.The extended state observer harmonic current suppression strategy is designed to reduce the tracking error of harmonic current,reduce the interference caused by environmental changes during motor operation,and improve the performance of fault-tolerant MPC.5)The experimental platform of a dual three-phase permanent magnet motor is established to verify the authenticity and effectiveness of the proposed methods,providing an empirical basis for the research of high-performance dual three-phase permanent magnet motor MPC.