Aja André Vandenput

Reference frames fit for controlling PWM rectifiers

The authors argue that one should keep things simple when controlling bidirectional pulsewidth modulation rectifiers by considering the utility grid as a virtual electric machine. The advantage is that the air-gap flux of this big machine can be directly measured in a straightforward way. Therefore, as shown in this paper, principles of field orientation can be applied to control the power flow, yielding high-dynamic performance.

Manifold-mapping optimization applied to linear actuator design

Optimization procedures, in practice, are based on highly accurate models that typically have an excessive computational cost. By exploiting auxiliary models that are less accurate, but much cheaper to compute, space mapping (SM) has been reported to accelerate such procedures. However, the SM solution does not always coincide with the accurate model optimum. We introduce manifold mapping, an improved version of SM that finds this precise solution with the same computational efficiency. By two examples in linear actuator design, we show that our technique delivers a significant speedup compared to other optimization schemes

Analytical and Numerical Techniques for Solving Laplace and Poisson Equations in a Tubular Permanent-Magnet Actuator: Part I. Semi-Analytical Framework

We present analytical and numerical methods for determining the magnetic field distribution in a tubular permanent-magnet actuator (TPMA). In Part I, we present the semianalytical method. This method has the advantage of a relatively short computation time and it gives physical insight. We make an extension for skewed topologies, which offer the benefit of reducing the large force ripples of the TPMA. However, a lot of assumptions and simplifications with respect to the slotted structure have to be made in order to come to a relatively simple semianalytical description. To model the slotting effect and the related cogging force, we apply a Schwarz-Christoffel (SC) mapping for magnetic field and force calculations in Part II of the paper. Validation of the models is done with finite-element analysis.

Electromagnetic and Thermal Design of a Linear Actuator Using Output Polynomial Space Mapping

This paper describes the optimization methodology used in the design of a slotted tubular permanent-magnet actuator for industrial applications. A time-effective optimization procedure is obtained by considering simple analytical design equations in coherence with 2-D finite-element analysis as means to establish the various design variables. The optimization is performed in a multiphysics environment because both electromagnetic and thermal models are created and used in the optimization routine. The original optimization problem is replaced by a surrogate, which is updated or improved iteratively by means of a space-mapping-based technique. Its application for solving coupled magnetic-thermal design problems for electric machines is a rather unexplored topic.

Optimization of Contactless Planar Actuator With Manipulator

This paper describes the optimization of a contactless electromagnetic planar actuator (6 degree-of-freedom) with manipulator on top of the floating platform. The manipulator causes disturbance forces and torques that must be counteracted by the magnetic bearings. In addition, the energy necessary to operate the manipulator is transferred by means of an inductive coupling, which is integrated in the magnetic bearings. The requirements for the planar actuator in such a system are discussed in this paper as well as the optimization variables, goals, and constraints. In addition, the influence of the accuracy of the combined analytical-numerical model of the planar actuator on the optimization is addressed. Finally, the topology is presented that meets all criteria.

Application of Schwarz-Christoffel Mapping to Permanent-Magnet Linear Motor Analysis

Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear synchronous motors. These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this paper, an elegant semianalytical approach is presented to acquire the force profile. First, the magnetic field distribution in the air gap is determined by means of Schwarz-Christoffel (SC) mapping. The SC mapping allows a slotted structure of the machine to be mapped to a geometrically simpler domain for which analytic solutions are available. Subsequently, the field solution in the slotted structure can be determined by applying the mapping function to the field distribution in the simplified domain. From the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The results are compared with those from the commonly used equivalent magnetic circuit modeling and 2-D FEM software to demonstrate the accuracy which can be reached by application of the SC method.

Analytical and Numerical Techniques for Solving Laplace and Poisson Equations in a Tubular Permanent Magnet Actuator: Part II. Schwarz–Christoffel Mapping

In Part I of the paper, we derive a semianalytical framework for the magnetic field calculation in the air gap of a tubular permanent-magnet (PM) actuator. We also make an extension for skewed topologies. However, the slotting effect and its related cogging force cannot be determined in a straightforward way. Therefore, in Part II, we apply the Schwarz-Christoffel (SC) conformal mapping method to one pole-pair of the tubular PM actuator. This mapping allows for field calculation in a domain where standard field solutions can be used. In this way, slotting effects can be taken into account; however, skewing cannot be implemented directly. The SC-conformal mapping method is valid only for two-dimensional Cartesian domains. We therefore apply a special transformation from the cylindrical to the Cartesian coordinate system to describe the tubular actuator as a linear actuator.

Design Considerations for a Semi-Active Electromagnetic Suspension System

Vehicle manufacturers always strive to improve the vehicle handling and passenger safety and comfort. One of the focus points for the automotive industry is the (semi-)active suspension system for which various commercial technologies are existing, varying from pneumatic to hydraulic. This paper addresses the design considerations of a tubular electromagnetic actuator for semi-active suspension

Space Mapping Optimization of a Cylindrical Voice Coil Actuator

An optimal design problem of an electromagnetic actuator is formulated by defining the set of design variables, the constraints, and the optimality criterion. Solving such a problem is a difficult and time-expensive task when many variables, constraints, and conflicting objectives are involved, and when high accuracy is required. In order to determine the solution in an efficient manner, the space mapping technique is investigated. A cylindrical voice coil actuator is chosen as a proof-of-concept example. The numerical results show that the approach is viable, and an obtained design is verified by measurements

Aggressive Output Space-Mapping Optimization for Electromagnetic Actuators

Automated electromagnetic actuator design can be achieved by means of several approaches. For example, one might consider fast, however, accuracy deficient coarse models or, in contrast, the design could be achieved exclusively by employing accurate, time expensive, fine models. The space-mapping optimization technique, with its input or output mapping based implementations, merges the advantages of the two extremes. A new algorithm variant that presents a simple structure, namely the aggressive output space-mapping, is proposed in this paper. The design problem of a tubular permanent magnet actuator is considered in order to compare the proposed algorithm with two existing techniques.