Semi-Analytical Dynamic Model of Permanent-Magnet Direct Current Brushed Motor Considering Slotting Effect, Commutation, and PWM-Operated Terminal Voltage

摘要

The aim of this paper is to model a permanent-magnet direct current (PMDC) brushed motor considering the slotting effect and the effect of armature reaction and subsequent commutation phenomenon. These space-domain effects are mapped to time-domain equations of PMDC brushed motor by applying finite element approach (FEA) based geometrical modeling of armature. Conventionally, pulse width modulation (PWM) based approach is widely used to control PMDC brushed motor that essentially requires more precise time-domain model. Incorporating the slotting effect as a function of armature position, a reluctance model of PMDC brushed motor is framed. With the help of the reluctance model and by applying FEA over armature geometry, variation of various space-domain parameters are determined as a function of armature position in space that takes slotting effect into consideration. Furthermore, the effect of armature reaction or commutation is also taken into consideration as a function of both space-domain and time-domain parameters. Also incorporating the variation of space-domain parameters’ due to slotting effect and armature reaction, the conventional dynamic behavioral time-domain equations are modified and reported with adequate simulation responses with PMDC brushed motor operated at various PWM duty cycle. These modified time-domain equations based simulation responses are further validated with satisfactory experimental results.