Hybrid thermal modeling of tubular linear oscillating motor based on sectionalized equivalent thermal circuit

Lumped parameter method based on Motor-CAD is a conventional and convenient method to analyze temperature characteristics of electric machines. It can directly display the temperature distribution and temperature variation in different nodes of the machine. However, it is only appropriate for eight kinds of traditional rotary motors, not suitable for linear motors. In this paper, a tubular linear oscillating motor (TLOM) is proposed to directly drive hydraulic servo pump in electro-hydrostatic actuator (EHA). A node thermal modeling method based on sectionalized equivalent thermal circuit is presented to analyze steady and transient thermal status of this linear motor, which reflects the spatial thermal characteristic in details and systematically. A research prototype of the motor has been developed, and thermal experiments under different current inputs are conducted. The temperature behaviors with/without forced airflow are studied and compared. Both finite element methods (FEM) and experimental results validate the analytical thermal models under different working situations. This study provides a simple method for design optimization and it is also greatly useful for control implementation of the TLOM.