电机气隙磁场调制行为及其转矩分析

Analysis of Airgap Field Modulation Behavior and Torque Component in Electric Machines

磁场调制行为在电机中普遍存在,调制行为与转矩成分关系较为复杂。基于“电机磁场调制理论”定义了广义磁场调制电机同步调制与异步调制行为及其同步转矩与异步转矩分量,并就其关键的差异分别进行对比、分析并举例阐明;对常见电机结构作用在转子上的转矩成分进行总结和归类,阐述了同步/异步调制与同步/异步转矩分量的辩证关系。基于上述理论分析及定义,对常见的磁场调制电机进行实例分析,研究无刷双馈感应电机可能的运行模式、存在条件及转矩分量构成,总结单馈同步模式下无刷双馈感应电机与电励磁同步电机的异同;分析多层磁障与短路线圈复合转子无刷双馈电机拓扑结构,定性描述辅助短路线圈在磁场调制行为中的作用,定义调制算子进而定量讨论复合转子给磁场耦合能力、平均电磁转矩等方面可能带来的有益影响;最后,对简单凸极类磁场调制电机的调制行为及转矩特性进行统一描述。

The synchronous and asynchronous modulation behaviors are the most basic modulation principles in electric machines.However,the relationship between synchronous/asynchronous modulation behavior and torque component is complicated,whose key characteristics are defined,compared,and exemplified based on the“general airgap field modulation theory”in this paper.The torque components of general magnetic field modulated machines are summarized and classified,and an important rule is expounded.Based on the theoretical analysis,this paper studies the possible operation modes,existence conditions and torque components of brushless doubly-fed induction machines(BDFIM),and summarizes the similarities and differences between it and the electrically excited synchronous machine in single-fed synchronization mode.The topology of the BDFM with composite rotor is depicted,and the role of auxiliary short-circuited coils and the modulation operator are provided qualitatively,based on which the potential advantages on the magnetic field coupling ability and average electromagnetic torque are discussed quantitatively.Finally,the modulation behaviors and torque characteristics of field modulated machines featuring simple salient poles are analyzed in a unified way.