It is difficult to meet the engineering requirements for a high-torque-density direct drive (HTDDD) permanent magnet synchronous machine (PMSM) using the thermal load design method for traditional motors. In this study, a waterway structure design method for a HTDDD PMSM depending on the motor thermal capacity is proposed based on a temperature cycling module. The design program of the motor waterway structure is based on a waterway thermal calculation and an equivalent thermal network method. The waterway structure can be rapidly designed by cyclic checking of the temperature at each node in the motor. A fluid-solid coupled temperature field simulation is used to analyze the influences of the thermal capacity, the waterway structure, and the water velocity on the temperature rise and the cooling effect of the motor. Finally, the algorithm is used to create a prototype, and the proposed method is experimentally validated.

This paper investigates the irreversible demagnetization (ID) of a large capacity line-start permanent magnet synchronous motor (LSPMSM) considering influence of permanent magnets’ (PMs) temperature. The phenomenon of ID occurs on the pull-in stage and close to the cusp of magnet on the direct-axis direction. The PMs’ temperature causes the demagnetization curve to move down and the knee point to shift up. The extensive area ID of magnet will lead to pulling in synchronism failure and operation at the asynchronous state. A prototype is fabricated to validate the analysis that temperature of PMs will bring more serious ID risk and degradation of motor performance.

The large permanent magnet synchronous machine(PMSM) usually adopts modularity technique to facilitate the manufacture and maintenance. In order to avoid the contact of adjacent coils between modules, a novel unwinding stator module combined permanent magnet synchronous machine (SMCPMSM) is proposed, in which each modular can operate independently. The number of input modules can be flexibly selected according to the torque requirement in the SMCPMSM of mill wrapping around to realize the optimal control of mill system efficiency. In this paper, the unwinding block method and its mathematical model of the SMCPMSM are described. The electromagnetic performance of the SMCPMSM and the operation performance of different power supply modules (PSMs) are analyzed, the radial force and electromagnetic vibration of the PSM in asymmetric operation is studied, which provides a reasonable basis for the part of PSM operation of the SMCPMSM in accordance with torque requirements.

With the development of new energy industries, the demand for the driving range and power quality of electric vehicle (EV) drive systems is growing rapidly. The drive motor is faced with the challenge of continuously improving power density and performance. This paper proposes a multiobjective optimization method for an interior permanent magnet synchronous motor for a traction drive (IPMSMTD). Based on the flat wire winding technology, the multiobjective optimization design of the IPMSMTD is carried out to improve the motor power density and high-efficiency range, reduce the torque ripple, and suppress the electromagnetic vibration and noise. The structure and size equation of the IPMSMTD are described. The mathematical model considering iron losses is established, and the optimization objectives are determined. Based on the genetic algorithm, a multiobjective optimization mechanism of the magnetic pole structure is established. The operation performance of the motor is analyzed by the finite element simulation and efficiency map. In order to ensure the comprehensive operation index of the IPMSMTD, the vibration noise and modal analysis are carried out, which verifies the rationality of the designed motor and the optimization method.

Due to the huge volume of gearless ball mill direct drive permanent magnet synchronous machine (PMSM), an unwinding modular technology is convenient for its redundant power control, manufacture and maintenance. Several module units are wrapped around the ball mill roller for direct drive. The motor frame adopts a modular structure to achieve complete decoupling between modules. And the cooling problem of the motor is very important for its stable operation. The traditional waterway structure design and cooling analysis methods are difficult to meet the engineering requirements of large modular permanent magnet synchronous machine (MPMSM). A 3D equivalent thermal network method is proposed to study the cooling problem of MPMSM. The design program of modular frame cooling structure is written based on a 3D equivalent thermal network method. According to the temperature distribution of each node, the cyclic check is carried out to quickly design the modular waterway. The cooling effect of the designed waterway structure is analyzed by fluid-solid coupled temperature field simulation. An 80 kW prototype is developed and the temperature rise experiment is carried out. The simulation and experiment results prove the rationality of a 3D equivalent thermal network method for the MPMSM cooling structure design.

With the large‐scale development of the ball mill, the direct‐drive gearless ball mill has emerged, eliminating the limitation of the transmission torque of large gear. However, it is difficult to process, transport, install and maintain the gearless ball mill because of its vast volume, and the coils cannot be decoupled freely. Therefore, this work proposes a module combined permanent magnet motor with wrapped type for mine ball mill (MBMWT‐MCPMM). Based on the principle of removing coils, the stator is modularized. Each module can be regarded as a small rotary motor, which improves the reliability and fault tolerance of the motor. In this work, the structure and general design process of the MBMWT‐MCPMM are described, and the electromagnetic performance is simulated and analysed. The influence of different factors on the cooling effect of the motor and the temperature rise of different modules during fault‐tolerant operation are analysed. An 80 kW prototype is developed, and its experiments are carried out. The experimental results verify the validity of the related design and analysis.