In this paper,mechanical and electrical integration technologies,including the content and status of studies of mechatronic systems provides a brief analysis and elaboration of hope for our colleagues to provide bit by bit to help.

Of mechatronic systems

A five-phase fault-tolerant combined star-pentagon synchronous reluctance machine (SynRM) can provide a high torque density, minimal torque ripple, and superior fault tolerance. To enhance the performance of SynRM in the case of an open-circuit fault, this article proposes an optimal current angle to maximize the torque and minimize the torque ripple under the fault condition. The drive system consists of a five-phase combined star-pentagon SynRM fed from a three-to-five-phase matrix converter (MC). When determining the operating point of maximum torque per ampere (MTPA), the influence of fault and saturation on the <inline-formula> <tex-math notation="LaTeX">$d$ </tex-math></inline-formula>- and <inline-formula> <tex-math notation="LaTeX">$q$ </tex-math></inline-formula>-axis inductances is considered. The healthy phases’ currents are reconstructed to guarantee a null value of zero-sequence current. Space vector modulation is applied to control the MC under the fault condition. Under the fault condition, the <inline-formula> <tex-math notation="LaTeX">$z$ </tex-math></inline-formula>-subspace is properly controlled to reduce the overall harmonic distortions of current. Moreover, the performance of the drive system is analyzed using the finite element method (FEM) simulation and MATLAB program. Finally, the experimental tests validate the effectiveness of the suggested approach on a SynRM prototype drive system with a three-to-five-phase MC.

An Enhanced Fault-Tolerant Control of a Five-Phase Synchronous Reluctance Motor Fed From a Three-to-Five-Phase Matrix Converter

This article deals with the power-sharing control of bearingless multisector and multithree-phase permanent magnet machines. The proposed control strategy allows to distribute the power flows among the three-phase inverters supplying the machine during bearingless operation of the drive. The control technique is based on the extension of the vector space decomposition modeling approach. The components producing the electromagnetic torque, i.e., the q -axis currents, are controlled independently from the d -axis ones, also with the aim of managing the power flows among the three-phase systems. Conversely, the d -axis currents are exploited for the generation of the radial forces needed to levitate the rotor, while considering the compensation of the forces caused by the q -axis currents in case of unbalanced power sharing strategy. The validity of the proposed method is confirmed by simulations and experimental tests on a prototyped bearingless multisector permanent magnet synchronous machine. The proposed approach is a contribution to the development of advanced control systems employing multiphase drives in the field of bearingless and multiport applications.

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Power-Sharing Control in Bearingless Multi-Sector and Multi-Three-Phase Permanent Magnet Machines

A linear-rotary motion permanent magnet (PM) generator is investigated with six axial modular E-shaped stator sections arranged circumferentially, which can meet the requirement of wave and tidal energies generation. The PM pole is magnetized in radial direction, and the adjacent PM poles with opposite magnetized directions are interlaced by half mover pole pitch both in circumferential and axial directions, which are located on the mover surface. The rotational and rectilinear motions are achieved by one magnetic circuit structure according to the transverse flux principle and electromagnetic induction principle. The optimization design and electromagnetic properties of the proposed motor are calculated by 3-D finite element simulation. Then the optimal structural parameters are obtained. The back electromotive force (back EMF) and harmonics, the amplitudes of the cogging torque and detent force are decreased than those of the initial topology. Since three phases of the nine phase windings generate same initial phase angle of back EMF whether it works in rotational or rectilinear motion, the traditional three phase energy storage system can be used to realize the energy storage of the nine phase windings, which reduces the difficulty of electrical energy storage. The variation of the amplitude of back EMF is hardly affected with different mover positions, which is conducive to improve the efficiency of marine energy power generation.

Design Optimization of Linear-Rotary Motion Permanent Magnet Generator With E-Shaped Stator

Direct drive tubular linear actuators (TLAs) may be used in various applications that require fast movements and high-precision positioning, e.g., pick-and-place robots. This article presents the analysis, dynamic electromechanical model derivation, controller design, and system operation of a TLA with integrated magnetic bearings (MBs). Furthermore, the actuator operation is verified with extensive measurements on the prototype, which include axial position step response, standard deviation of the steady-state positions and mover tilting control. Compared with any conventional TLA, which may perform only linear motion, the mover tilting control is possible due to integrated MBs. This gives the new actuator a great advantage in high-precision positioning systems, since any thermal expansions of the parallel kinematics may be compensated.

Dynamic Electromechanical Model and Position Controller Design of a New High-Precision Self-Bearing Linear Actuator

Rotary–linear electric machines can perform coupled rotary and linear motion. In addition, they can have magnetic bearings (MBs) integrated and magnetically coupled with the rotary, linear, or rotary–linear machine operation. Since rotary–linear machines with MBs have not been thoroughly analyzed in the literature, the models that provide understanding of their operation and give basis for the control system implementation are not entirely covered. Hence, in this article, an enhanced complex space vector-based model of the rotary–linear machine with MBs is derived and expressions for the torque, thrust force, and MB force are given. The rotary–linear machine complex space vector of the voltage, current, or flux linkage is defined using the proposed transformation with two complex frames: one related to the rotation and MBs and another to the linear motion. This results in complex space vectors with two complex units; however, the techniques used for a conventional complex space vector calculation can also be applied to the proposed complex space vector description. This is also experimentally validated on a hardware prototype of a magnetically levitated linear tubular actuator (MALTA), whose position control system is designed and implemented based on the enhanced space vector modeling approach, with the dynamic operation of the MALTA, including linear motor operation with an axial stroke of 10mm and a mechanical frequency of 17Hz.

Enhanced Complex Space Vector Modeling and Control System Design of Multiphase Magnetically Levitated Rotary–Linear Machines

Linear-rotary actuators (LiRAs) are today used in industry applications where a controlled linear and rotary motion is necessary such as pick-and-place robots, servo actuation of gearboxes or tooling machines. However, in special industry applications that require high purity and/or high precision positioning, the usage of conventional LiRAs with mechanical bearings is limited. Therefore, in this paper a LiRA with integrated magnetic bearings, i.e. a selfbearing/bearingless LiRA, is analyzed. The actuator employs concentrically arranged linear and rotary stators placed inside and outside a cylindrically shaped mover, which results in a so-called selfbearing double-stator (SBDS) LiRA. A FEM geometry optimization of the SBDS LiRA is performed and Pareto performance plots concerning linear force and torque generation are obtained. A SBDS LiRA hardware demonstrator and an 18-phase inverter power supply hardware prototype are built and their operation is experimentally verified by rotary and linear position step response measurements.

Design and Experimental Analysis of a Selfbearing Double-Stator Linear-Rotary Actuator

This paper investigates the design of an Eddy Current Sensor (ECS) for position measurement of a moving conductive target located behind a fixed conductive shielding surface. Such a sensor can e.g. be used in completely sealed actuators with magnetically levitated rotor or mover for high purity applications. A detailed analysis of the sensor is conducted, starting from the conventional ECS and its equivalent circuit model, which is then further extended to an ECS looking through a conductive wall. With the aid of Finite Element Methods (FEM) simulations, a deeper understanding of the sensor operating principle is provided, together with guidelines to select its optimal excitation frequency, based on the properties of the selected materials for the target and the shielding surface. A sensitivity analysis is then conducted and the results are finally verified with measurements on a hardware sensor prototype, showing that the sensor can be used to capture the mover position in an active magnetic bearing control structure.

"Looking Through Walls" – Actuator Position Measurement Through a Conductive Wall

This paper investigates the design of an Eddy Current Sensor (ECS) for position measurement of a moving conductive target located behind a fixed conductive shielding surface. Such a sensor can e.g. be used in completely sealed actuators with magnetically levitated rotor or mover for high purity applications. Starting from the analysis of the sensor’s operating principle, the design of the excitation coil, the achievable sensitivity and bandwidth as well as the temperature stability of the sensor are investigated. Subsequently, a suitable sensor interface, consisting of the driving and signal conditioning electronics, is selected. With this it is possible to distinguish between position and temperature variations, for which the optimal operational frequencies are identified. The results are finally verified with measurements on a hardware sensor prototype, showing that the ECS can achieve a sensitivity of 1 mV/µm, a position resolution of 1 µm, with a measurement bandwidth of 30 kHz and can hence be used to capture the mover’s position in an active magnetic bearing feedback control structure.

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Rosario V. Giuffrida

Papers

Enhanced Complex Space Vector Modeling and Control System Design of Multiphase Magnetically Levitated Rotary–Linear Machines

Dynamic Electromechanical Model and Position Controller Design of a New High-Precision Self-Bearing Linear Actuator

Design and Experimental Analysis of a Selfbearing Double-Stator Linear-Rotary Actuator

"Looking Through Walls" – Actuator Position Measurement Through a Conductive Wall

Highly Dynamic Eddy-Current-Based Sealed Magnetic Bearing Position Measurement With Temperature Drift Correction - “Seeing Through Conductive Walls”