Research On Dual-Mechanical-Port Flux-Swithing Permanent Magnet Brushless Motor And Multi-Mode Drive Control

In recent years, with the continuous concerns of energy and environment, a type of new energy vehicles based on the concept of high electrification and high energy efficiency have been developed rapidly in a global scale, such as the electric vehicles(EVs) and hybrid EVs (HEVs). Meanwhile, to meet the requirements of the complex modern driving cycles, the strict demands of high transmission efficiency, multi-mode operation capability, small size and light weight are required to be achieved for the motor driving system in the new energy vehicles. As a new type machines with two input ports or output ports, dual-mechanical-port permanent magnet (DMP-PM)machines have drawn increasing concerns,mainly since it not only has high power/torque density, high efficiency, and wide speed range, but also possesses compact structure, flexible power transmission and abundant operation modes. And it is quickly becoming one of the research hotspots in the modern HEVs traction motor.This paper proposes a DMP flux-switching PM brushless (DMP-FSPMBL)machine, which incorporates the concept of stator-PM machine into the DMP machine design. And a deep and systematic theoretical analysis and experimental studies are conducted in the paper, and the main contents are given as follows:1. By integrating the design concept of the FSPM machine with high power density and high efficiency into the DMP-PM machine, the new DMP-FSPMBL machine is proposed. Based on the elaborations of the motor structure features and operation principle, the power sizing equations of the inner and outer motors are established, consisting of pole-slot combination, PM topology, number of turns of winding, and rated phase current. In addition, by using magnetic circuit method, the magnetic coupling between the inner and outer motors is analyzed qualitatively, thus determining the design scheme of the flux barrier to reduce the magnetic coupling between the inner and outer motors.2.In the study perspectives of magnetic and electric loadings, by introducing the design idea of optimal power allocation between the inner and outer motors into the DMP-FSPMBL machine design, the optimal machine split ratio is explored and studied at multiple restrictions of structure parameters and total power.3. According to the features of high integration and complex magnetic circuit in the DMP-FSPMBL machine, a multi-objective optimization strategy based on the parameter sensitivity layering is proposed in this paper. And by purposely arranging the response surface method and multi-objective genetic algorithm into the different levels, the comprehensive tradeoff and optimal performances design among the output torque, torque ripple and magnetic coupling can be realized. It offers a relatively effective design ideas and method to offer a fast and efficient design for the PM machines with complex structure..4. By using finite element (FE) method, the performances of the DMP-FSPMBL machine are evaluated and analyzed in detail, mainly including back-EMF, cogging torque, inductance, torque, torque ripple and magnetic coupling, initially verifying the reasonability of machine structure and validation of optimization design method.Moreover, the efficiency MAP and various current angle MAP during the whole operation range are investigated, revealing that the DMP-FSPMBL machine can offer potential capability of high operation efficiency and reliability operation on a wide speed range.5. By integrating a non-contact magnetic planetary gear (NC-MPG) into the DMP-FSPMBL machine,a brushless electromagnetic hybrid powertrain is proposed in this paper, which has compact system space and high power integration. And, by establishing the mathematical models of the hybrid powertrain,the multiple operation modes and power flows of the transmission ways under complex driving cycles are investigated initially.6. By establishing the vehicle simulation model of the DMP-FSPMBL machine,the vehicle control strategy of pure electric priority is studied for evaluating the capability of the continuous change of speed and load. And, based on the test cycle of New European Driving Cycle (NEDC), the continuous driving capability of the machine and its powertrain are analyzed, and the potential application feasibility is also discussed.7. By manufacturing the prototype of the DMP-FSPMBL machine and establishing the corresponding hybrid powertrain test platform, the basic machine performances and the variable speed and load driving characteristics of the powertrain under multiple operation modes are tested and evaluated comprehensively.The theoretical analysis and experimental results verify the effectiveness and correctness of the proposed DMP-FSPMBL machine and its hybrid powertrain, and it further confirms that the hybrid powertrain based on the machine possesses the driving capability of multi-mode operation, which provides a theoretical support and experimental basis for their potential HEVs application.