Comparative Analysis And Optimization Research Of Modulated Permanent-Magnetic Gear Machine

In the context of carbon peak and neutrality,improving the efficiency of new energy conversion to electric energy and increasing the application proportion of electric energy on the consumer side are the keys to China’s energy transformation.Modulated Permanent-Magnet Gear Machine have broad application prospects in wind power generation,electric vehicles and oil pumping units due to their advantages of low-speed high-torque.The Field Modulated Permanent-Magnet Gear Machine(FPGM)radially integrates the field modulated magnetic gear and the permanent magnet machine.It has the characteristics of compact structure and high transmission efficiency.By improving the FPGM structure,it can form a Bidirectional Permanent-Magnet Excited Gear Machine(BPEGM)to further enhance the electromagnetic torque.Based on the principle of magnetic field modulation and finite element calculation,this paper analyzes and studies the torque generation mechanism,parameter response,and electromagnetic characteristics of FPGM and BPEGM under no-load and load conditions.The main research work and research results of this paper include the following aspects:(1)Based on the mathematical model of permanent magnet magnetomotive force and specific permeability,the magnetic field modulation mechanism of FPGM and BPEGM and the harmonic composition of airgap flux density are qualitatively analyzed.The contribution of each airgap magnetic flux density of each pair of poles to the electromagnetic torque is quantitatively studied,and the key role of dual modulation and dual excitation in improving the electromagnetic torque of BPEGM is revealed.(2)Comparative analysis of FPGM and Fractional-slot Concentrated Winding PMSM(FSCW-PMSM),the research shows that FPGM can produce torque multiplication effect through magnetic field modulation effect;based on Maxwell stress tensor method,the force density and electromagnetic torque of FPGM and FSCW-PMSM are obtained,studies show that FPGM increases electromagnetic torque by increasing the tangential airgap flux density amplitudes of the permanent magnet and armature windings.(3)The power generation characteristics of FPGM such as no-load back EMF and voltage regulation are verified through the FPGM independent load power generation experiment,which shows that the FPGM has good operating characteristics under the independent load power generation condition;the data obtained through the finite element analysis are basically consistent with the experimental results of the prototype,indicating that the finite element analysis method has high reliability.(4)The response of electromagnetic torque and torque ripple of FPGM and split-tooth FPGM to various airgap structural parameters is analyzed,and the two are optimized based on the genetic algorithm in Ansys EM to facilitate comprehensive consideration;The change law of electromagnetic torque and power factor of FPGM under different transmission ratios is obtained by element method,which provides theoretical basis and finite element analysis method for the design and optimization of Modulated Permanent-Magnet Gear Machine.(5)The FPGM was improved and the BPEGM model was obtained by the optimization method,and the no-load characteristics,overload characteristics and speed regulation characteristics of BPEGM were analyzed;compared with FPGM,the results showed that BPEGM has higher electromagnetic torque,but its flux-weakening properties can not be as good as FPGM.