Influence law on the driving torque of a large gap magnetic driving system regarding the electromagnetic state switching offset angle

Xu Yan - Liang Liang - Cheng Lizhi - Liu Yunlong

Changsha University, Changsha, Hunan, China 410003

Abstract
The driving torque is an important performance parameter of a magnetic driving system. According to the working principle of the large gap magnetic driving system, in this study, four driving torque curves were simulated at different electromagnet states NS, NN, SN and SS. Based on the driving torque curves, the influence law on the driving torque regarding an electromagnet state switching offset angle ∆θ was studied. In order to keep the driving torque maximum, the relationship of h, a, ϕ and ∆θ was clarified and the best ∆θ was determined for different system structural parameter conditions. Using an experimental setup, the maximum rotation rate n, the load torque T_L and the driving torque T_D can be calculated after the pulse frequency f, the flow Q, the blood pump outlet pressure P_e and the coil current I are measured. So, the influence law on the system driving torque regarding the electromagnet state switching offset angle ∆θ has been proved by comparing theoretical and experimental results. Tables 3, Figs 12, Refs 10.