Constant Power Field Research Articles

Non-Simplicial Delaunay Meshing via Approximation by Radical Partitions

We consider the construction of a polyhedral Delaunay partition as a limit of the sequence of power diagrams (radical partitions). The dual Voronoi diagram is obtained as a limit of the sequence of weighted Delaunay partitions. The problem is reduced to the construction of two dual convex polyhedra, inscribed and superscribed around a circular paraboloid, as a limit of the sequence of pairs of general dual convex polyhedra. The sequence of primal polyhedra should converge to the superscribed polyhedron and the sequence of the dual polyhedra converges to the inscribed polyhedron. We are interested in the case when the vertices of primal polyhedra can move or merge together, i.e., no new faces are allowed for dual polyhedra. These rules define the transformation of the set of initial spheres into the set of Delaunay spheres using radius variation and sphere movement and elimination. Existence theorems are still unavailable but we suggest a functional measuring the deviation of the convex polyhedron from the one inscribed into the paraboloid. It is the discrete Dirichlet functional for the power function which is a linear interpolant of the vertical distance of the dual vertices from the paraboloid. The functional's absolute minimizer is attained on the constant power field, meaning that the inscribed polyhedron can be obtained by a simple translation. This formulation of the functional for the dual surface is not quadratic since the unknowns are the vertices of the primal polyhedron, hence, the transformation of the set of spheres into Delaunay spheres is not unique. We concentrate on the experimental confirmation of the approach viability and put aside mesh quality problems. The zero value of the gradient of the proposed functional defines a manifold describing the evolution of Delaunay spheres. Hence, Delaunay-Voronoi meshes can be optimized using the manifold as a constraint.

ПОСТРОЕНИЕ НЕСИМПЛИЦИАЛЬНЫХ СЕТОК ДЕЛОНЕ ПОСРЕДСТВОМ АППРОКСИМАЦИИ РАДИКАЛЬНЫМИ РАЗБИЕНИЯМИ

We consider the construction of a polyhedral Delaunay partition as a limit of the sequence of power diagrams (radical partitions). The dual Voronoi diagram is obtained as a limit of the sequence of weighted Delaunay partitions. The problem is reduced to the construction of two dual convex polyhedra, inscribed and superscribed around a circular paraboloid, as a limit of the sequence of pairs of general dual convex polyhedra. The sequence of primal polyhedra should converge to the superscribed polyhedron and the sequence of the dual polyhedra converges to the inscribed polyhedron. We are interested in the case when the vertices of primal polyhedra can move or merge together, i.e., no new faces are allowed for dual polyhedra. These rules define the transformation of the set of initial spheres into the set of Delaunay spheres using radius variation and sphere movement and elimination. Existence theorems are still unavailable but we suggest a functional measuring the deviation of the convex polyhedron from the one inscribed into the paraboloid. It is the discrete Dirichlet functional for the power function which is a linear interpolant of the vertical distance of the dual vertices from the paraboloid. The functional's absolute minimizer is attained on the constant power field, meaning that the inscribed polyhedron can be obtained by a simple translation. This formulation of the functional for the dual surface is not quadratic since the unknowns are the vertices of the primal polyhedron, hence, the transformation of the set of spheres into Delaunay spheres is not unique. We concentrate on the experimental confirmation of the approach viability and put aside mesh quality problems. The zero value of the gradient of the proposed functional defines a manifold describing the evolution of Delaunay spheres. Hence, Delaunay-Voronoi meshes can be optimized using the manifold as a constraint.

Dual three‐phase permanent magnet synchronous machine investigation for battery electric vehicle power‐trains

A dual three-phase machine with interior permanent magnet rotor and distributed winding has been studied and compared to a commercial automotive traction machine, the Nissan Leaf IPM machine. The performance of the two designs are compared for typical traction operating points, via high torque, low speed and low torque, high speed, and constant power field weakening operation. The dual three-phase machine is shown to have improved torque density and torque quality without compromising efficiency.

The Research on Full-speed Field Weakening Control Method of Electric Vehicle Interior Permanent Magnet Synchronous Motor

The motor drive system represents a key technology for development of the electrical vehicles, and the permanent magnet synchronous motor becomes the mainstream of the new energy vehicle drive motor for the superior performances in power density, low-speed torque density, efficiency and reliability. The paper studies the field weakening control strategy for the interior permanent magnet synchronous motor (IPMSM) and provides a field weakening control strategy for the IPMSM at the full-speed range. By studying the mathematical IPMSM model and the methods of conventional vector control and analyzing the operating conditions of the IPMSM at the full-speed range, the paper divides the operating conditions into constant torque operation region I, constant torque operation region II, constant power field weakening operation region and high-speed field weakening operation region to confirm the control strategy algorithm in each region and the transition conditions between regions and provide the current control strategy that the d-axis current and q-axis current are confirmed by the reference torque and the feedback speed. Modeling of the field weakening control strategies in each region is made through the Matlab/Simulink, and simulation of the operating conditions with a steady-state load and a dynamic load is done to verify that the field weakening control strategy in each region is feasible. A co-simulation is made by combining the Matlab/Simulink-based control model, the RecurDyn-based virtual prototype and the RT-LAB to verify the feasible field weakening control strategy.

Nonlinear Load-Adaptive MIMO Controller for DC Motor Field Weakening

Control problem of field weakening for a separately excited DC motor system, modeled in nonlinear differential equations, is tackled in this paper. A novel constant power field weakening controller, based on nonlinear load-adaptive multi-input multi-output (MIMO) linearization technique, is developed to achieve high-performance speed tracking through rejecting load disturbance. The effects of decoupling and linearization permit the controller to be implemented and operated at desired field weakening point of operation. Computer simulations are presented to demonstrate the effectiveness of the proposed controller for a specific motor. It has been shown that the proposed controller provides higher dynamic performance in comparison with traditional PI controllers, whereas the motor system is run over wide dynamic field weakening regimes.

High performance nonlinear MIMO field weakening controller of a separately excited dc motor

Abstract This paper presents a novel technique for field weakening implementation of separately excited dc motors. A constant power field weakening controller, which is based on nonlinear load adaptive multi-input multi-output (MIMO) linearization technique, is proposed and developed for achieving speed tracking. Due to the effects of decoupling and linearization, it allows the controller to be implemented and operated at any desired field weakening point of operation. To demonstrate the effectiveness of the proposed controller, the results of computer simulations are presented for a specific motor. The performance of this proposed controller is compared with that of the traditional linear PI controllers. The results show that the proposed controller provides the globally higher speed control performance, while the motor is operated over a wide dynamic regime of field weakening, even under the presence of load torque disturbance.

Nonlinear MIMO Speed Sensorless Controller for DC Motor Field Weakening

This paper addresses speed control of a separately excited DC motor (SEDCM) in nonlinear field weakening region. Input output linearization (IOL) technique is used to deal with the motor system with considerable nonlinearity, and a nonlinear multi-input multi-output (MIMO) speed tracking controller is developed for constant power field weakening. The effects of decoupling and linearization permit the controller to be implemented and operated at any desired field weakening point of operation. The control scheme combining this controller with nonlinear speed/load torque observer is, in particular, proposed for speed sensorless operation. Computer simulations are presented to show speed tracking performance of the proposed overall scheme.