Cooling System Design and Thermal Analysis of Modular Stator Hybrid Excitation Synchronous Motor

Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind power generation and other fields. This paper introduces the basic structure of hybrid excitation motor with modular stator, and analyzes the operation principle of hybrid excitation motor. The cooling structure of the water-cooled plate is designed, and the effects of the thickness of the water-cooled plate and the number of water channels in the water-cooled plate on the heat dissipation capacity of the water-cooled plate are analyzed by theoretical and computational fluid dynamics methods. The effects of different water cooling plate structures on water velocity, pressure drop, water pump power consumption and heat dissipation capacity were compared and analyzed. The influence of different inlet flow velocity on the maximum temperature rise of each part of the motor is analyzed, and the temperature of each part of the motor under the optimal water flow is analyzed. The influence of the traditional spiral water jacket cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of the motor components is compared and analyzed. The results show that the water-cooled plate cooling structure is more suitable for the modular stator motor studied in this paper. Based on the water-cooled plate cooling structure, the air-water composite cooling structure is designed, and the effects of the air-water composite cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of each component of the motor are compared and analyzed. The results show that the maximum temperature rise of each component of the motor is reduced under the air-water composite cooling structure.

Research on a direct torque control for an electrically excited synchronous motor drive with low ripple in flux and torque

The electrically excited synchronous motor(ESM)has typically small synchronous inductance values and quite low transient values because of the damper windings mounted on the rotor.Therefore,the torque and stator flux linkage ripples are high in the direct torque control(DTC)drive of the ESM with a torque and flux linkage hysteresis controller(basic DTC).A DTC scheme with space vector modulation(SVM)for the ESM was investigated in this paper.It is based on the compensation of the stator flux link-age vector error using the space vector modulation in order to decrease the torque and flux linkage ripples and produce fixed switching frequency under the principle that the torque is controlled by the torque angle in the ESM.Compared with the basic DTC,the results of the simulation and experiment show that the torque and flux linkage ripples are reduced,the maximum current value is decreased during the startup,and the current distortion is much smaller in the steady-state under the SVM-DTC.The field-weakening control is incorporated with the SVM-DTC successfully.