Self‐excited hybrid‐field synchronous motors

Abstract

SUMMARYThis paper proposes a new well-organized dynamic mathematical model and new dynamic vector simulators for newly emerging self-excited hybrid-field synchronous motors (SelE-HFSMs) that have rotor field by both permanent magnet and diode-shorted field winding. The proposed new mathematical model has the following completeness and generality: (1) it consists of three consistent basic equations such as circuit, torque-evolution, and energytransmission equations; (2) it deals with pole saliency and contains nonsaliency as a special case; (3) it is a dynamic model and contains a static one as a special case; and (4) it is established in the general reference frame including the stator and rotor reference frames as special cases. The proposed new dynamic vector simulators are established in the form of a vector block diagram based on the new model. They have the following attractive features: (1) they succeed in realizing clear configurations with physically meaningful vector signals, which clearly show motor electromagnetic mechanism; (2) vector signals utilized as transfer signals between blocks are defined in the general reference frame; consequently, the simulators in the frame can be directly and easily reduced to the ones in the stator and rotor reference frames; (3) they are compact, and can be easily programmed by commercially available standard simulation software. Two typical and compact but sufficiently general dynamic vector simulators are newly presented. Validity of the model is verified analytically, and validity of the simulators is confirmed by numerical experiments.

A new method for estimating initial rotor phase of self‐excited hybrid‐field synchronous motors

“…This can be assured by increasing the frequency ω h , but this results in a shorter diode off-time [4]. Therefore, the norm of the high-frequency current vector pointing at the N-pole approaches its maximum value, and determination of the NS-polarity becomes difficult [7].…”

“…This characteristic with respect to the equivalent inductance variation is specific to the d-axis current caused by switching the diode on and off (strictly speaking, it is remotely related to the existence of the field winding resistance) [4], which remains true under the following condition:…”

“…The model is composed of three matched fundamental equations: a circuit equation (first fundamental equation) that describes dynamic electromagnetic relations, a torque equation (second fundamental equation) that describes the torque generation mechanism, and an energy equation (third fundamental equation) that describes the dynamic process of energy conversion and transfer [4,5]. This model ignores the effect of magnetic flux saturation.…”

“…Figure 2 shows the verification system in terms of voltage application and current detection. The SelE-HFSM in the diagram was simulated with a dynamic vector simulator proposed by Shinnaka [4,5], and an ideal two-phase inverter was assumed. In the verification system, the detection reference frame, in which a high-frequency voltage is applied and the current is detected, is the γδ generalized reference frame fixed at a known phase θ αγ .…”