Research Of Multiport Motor Drives With Wide Power Range

Hybrid new energy vehicles have the advantages of long mileage,high energy conversion rate,high power density and multi-energy complementarity.It is one of the important technical routes to achieve the national " double carbon " strategic goal.The multi-port motor driver can connect multiple energy sources to the AC motor.The singlestage multi-port motor driver has the characteristics of less energy conversion times and high energy conversion efficiency.It is a motor drive scheme with great development potential.However,the current single-stage multi-port motor driver topology has a limited power adjustment range for the DC-side energy source,and cannot be applied to the complex operating conditions of new energy vehicles.Therefore,thesis introduces a multi-port topology suitable for wide power range,and proposes a space vector modulation strategy suitable for wide power range based on this structure.The specific research contents are as follows :Aiming at the problem of small power adjustment range of unipolar multi-port motor driver,thesis analyzes the composition and power path of the existing single-stage multiport driver topology,and introduces a wide power range multi-port motor driver.The DC port power adjustment range of the topology is wider,and it can be applied to the working conditions with large DC port power variation range to achieve flexible power distribution requirements.In order to improve the operating efficiency of the driver,based on the in-depth study of the relationship between different voltage space vectors and port power distribution,thesis proposes a space voltage vector modulation method with power distribution.In addition,thesis combines the different DC bus voltages required by the motor under different working conditions,and adopts the low bus voltage operation mode as far as possible to reduce the voltage drop on the stator resistance and improve the efficiency of the motor drive system.On the basis of circuit design and modulation design,in order to optimize the efficiency of multi-port motor driver with wide power range,thesis proposes an efficiencyoptimized multi-port motor driver control algorithm.Based on the analysis of the power distribution range of the multi-port single-stage driver,when the DC port power demand is within the power adjustment range of the multi-port driver,the DC / DC converter does not participate in the power control,and all power only needs a single conversion.When the power demand of the DC port exceeds the power adjustment range of the multi-port driver,the multi-port driver is output in the maximum power distribution range,and the DC / DC converter only processes the remaining part of the power to reduce the power loss of the system.The overall efficiency of the system is 1 ～ 2 % higher than that of the traditional topology.In summary,the motor driver and its control method of hybrid new energy vehicles proposed in thesis have the characteristics of wide power adjustment range and high energy conversion efficiency,and have very important development potential.