电励磁凸极同步电机磁阻转矩及其利用率提升方法研究

Investigation on the Method of Improvement and Utilization of Reluctance Torque of Wound Field Synchronous Machine with Salient Pole

在电励磁凸极电机转子侧设置一定数目的磁障,增大电机凸极比,提高磁阻转矩。基于等效磁路法,推导电机的转矩方程,揭示影响磁阻转矩的几何参数。利用有限元开展电磁场计算,针对转子侧设置单磁障和双磁障的方案,获取磁障宽度和磁障之间距离的合理尺寸。为了提升磁阻转矩的利用率,进一步提升总转矩,在磁障内设置永磁体,通过合理设置永磁体的充磁方向实现磁偏置,减小励磁转矩和磁阻转矩达到最大值时的电流角差。结果表明,当磁障宽度占转子极宽的8.5%,磁障之间的距离占转子极宽的5.7%时,转矩提升效果较好。和传统电励磁电机相比,设置磁障后电励磁电机的总转矩提升13.9%,实现磁偏置后电机的总转矩在设置磁障的基础上提升14.5%。

A certain number of flux barriers were set on the rotor side of the wound field synchronous machine with salient pole to increase the saliency ratio and reluctance torque.The torque equation of the motor was derived using the equivalent magnetic circuit,which was used to reveal the geometric parameters affecting the reluctance torque.The electromagnetic field was calculated by finite element method to obtain the reasonable width of flux barrier and the distance between flux barriers.In order to improve the utilization of reluctance torque and further the total torque,permanent magnets were set in the magnetic barrier,and the magnetic bias was realized by reasonably setting the magnetization direction of permanent magnets,so as to reduce the current angle difference when the excitation torque and reluctance torque reach the maximum value.The results show that the effect of torque improvement is better when the width of the flux barrier and the distance between flux barriers account for 8.5%and 5.7%of the width of the rotor pole.Compared with the traditional wound field synchronous machine,the total torque of machine with flux barrier increases by 13.9%.After realizing magnetic bias,the total torque is increased by 14.5%on the basis of setting flux barrier.