Spasoje Miric

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Miric

First Name

Spasoje

ORCID

0000-0001-7885-6093

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Publications 1 - 10 of 35

New Concept for Current-Impressed WPT to Multiple Independent Stainless-Steel-Enclosed Linear Actuator Sliders
Jayathurathnage, Prasad; Miric, Spasoje; Xu, Junzhong; et al. (2022)
2022 IEEE 7th Southern Power Electronics Conference (SPEC)
Linear actuators (LAs) in pharmaceutical or chemical industries must be encapsulated into stainless steel (SS) enclosures to comply with extreme purity standards and facilitate thorough cleaning and disinfection. Therefore, advantageously wireless power transfer (WPT) should be used to supply the sliding part of such actuators, with the primary winding extended to cover the entire LA stroke, such that hard-to-clean cable carrier assemblies can be eliminated. Typically multiple independent sliders and/or tool carriages must then be supplied from the same primary winding, resulting in a multi-receiver WPT system. However, providing power with a voltage-impressed method to such a system is challenging due to the voltage sharing among the receivers. Therefore, this paper proposes a novel current-impressed method suitable for multi-receiver WPT systems. The proposed method is thoroughly analyzed, optimized, verified by circuit simulations, and compared against a conventional current-impressed approach. As a result, the proposed method facilitates overload capability and has higher efficiency. The exemplary system is designed for two 100W tool carriages and 72V DC input and output voltages.
Enhanced Complex Space Vector Modeling and Control System Design of Multiphase Magnetically Levitated Rotary–Linear Machines
Miric, Spasoje; Giuffrida, Rosario V.; Bortis, Dominik; et al. (2020)
IEEE Journal of Emerging and Selected Topics in Power Electronics
Highly Dynamic Eddy-Current-Based Sealed Magnetic Bearing Position Measurement with Temperature Drift Correction - "Seeing Through Conductive Walls"
Giuffrida, Rosario V.; Miric, Spasoje; Kolar, Johann W.; et al. (2022)
IEEE Open Journal of the Industrial Electronics Society
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.
Design and Experimental Analysis of a New Magnetically Levitated Tubular Linear Actuator
Miric, Spasoje; Kuttel, Pascal; Tüysüz, Arda; et al. (2018)
IEEE Transactions on Industrial Electronics
Linear-Rotary Bearingless Actuators
Miric, Spasoje (2021)
Self-Bearing Linear-Rotary Actuators with Wireless Power Transfer for High-Purity and Precision Applications
Miric, Spasoje; Giuffrida, Rosario V.; Jayathurathnage, Prasad; et al. (2023)
New Triple-Output Quad-Active-Bridge DC/DC Converter Employing a Four-Leg Inverter Input Stage
Ohno, Takanobu; Miric, Spasoje; Guillod, Thomas; et al. (2023)
2023 26th International Conference on Electrical Machines and Systems (ICEMS)
Charging stations for electric vehicles require electrical isolation between the charging ports. Therefore, this paper proposes a multi-port DC/DC converter structure that combines three conventional dual-active bridge converters (DABCs) where the primary side switching stages are integrated into a single four-leg inverter, and three individually isolated output ports (4L3) are provided. This quad-active bridge converter (QABC) structure features fewer semiconductor devices than three parallel connected single-phase DABCs with a six-leg inverter (3×2L3, resulting in 6L3). The 4L3 QABC is also advantageous compared to a known variant where the primary side switching stages are integrated into a three-leg inverter (3L3), as the 4L3 QABC does not limit the duty cycles of the primary side transformer voltages. Therefore, the input voltage can be fully utilized, which allows lower transformer RMS currents compared to the conventional 3L3 QABC. Our analysis explains the operation and modulation and underscores the 4L3 QABC’s enhanced performance that consistently diminishes transformer current across all operational ranges, achieving a 20% reduction in the sum of squared transformer RMS currents at rated operation compared to the conventional 3L3 QABC. Furthermore, we show a virtual prototype with an integrated cooling system, which reaches a power conversion efficiency of 98.4% for 750V/400V primary/secondary voltages at 120kW and a power density of 10kW/dm3.
Design and Experimental Analysis of a Selfbearing Double-Stator Linear-Rotary Actuator
Miric, Spasoje; Giuffrida, Rosario; Rohner, Gwendolin; et al. (2021)
2021 IEEE International Electric Machines and Drives Conference (IEMDC)
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.
Analysis and Performance Evaluation of a Three-phase Sparse Neutral Point Clamped Converter for Industrial Variable Speed Drives
Cittanti, Davide; Guacci, Mattia; Miric, Spasoje; et al. (2022)
Electrical Engineering
This paper analyzes the operation and characterizes the performance of a three-phase three-level (3-L) Sparse Neutral Point Clamped converter (SNPCC) for industrial variable speed drives (VSDs). The operating principle of the SNPCC, which advantageously employs a lower number of power transistors than a conventional 3-L inverter, is described in detail, focusing on the AC-side differential-mode and common-mode voltage formation and on the DC-side mid-point current generation processes. The degrees of freedom in the SNPCC modulation scheme are defined and several switching sequences are investigated. Afterwards, the stresses on the active and passive components (e.g. semiconductor losses, machine phase current ripple, DC-link capacitor RMS current, etc.) are calculated by analytical and/or numerical means, enabling a straightforward performance comparison among the identified switching sequences. The most suited modulation strategy for VSD applications is then selected and a chip area sizing procedure, aimed at minimizing the total semiconductor chip size, is applied to a 800V 7.5kW three-phase system. The performance limits of the designed SNPCC are evaluated and finally compared to the ones of conventional 2-L and 3-L solutions, highlighting the promising cost/performance trade-off of the analyzed topology.
Comparative Evaluation of Three-Phase Three-Level Flying Capacitor and Stacked Polyphase Bridge GaN Inverter Systems for Integrated Motor Drives
Rohner, Gwendolin; Huber, Jonas; Miric, Spasoje; et al. (2024)
Electronics
This article presents a comprehensive comparative evaluation of a three-phase Three-Level (3L) Flying Capacitor Converter (FCC) and a Stacked Polyphase Bridge Inverter (SPBI), specifically a converter system formed by two Series-Stacked Two-Level three-phase Converters (2L-SSC), for the realization of a 7.5 kW Integrated Motor Drive (IMD) with a high short-term overload capability. The 2L-SSC requires a motor with two three-phase windings and a split DC-link, but uses standard six-switch, two-level transistor configurations. In contrast, the bridge legs of the 3L-FCC feature flying capacitors whose voltages must be actively balanced. Despite the 800 V DC-link voltage, both topologies employ the same set of 650 V GaN power transistors, i.e., the same total chip area, and if operated at the same switching frequency, show identical semiconductor losses. Electric Discharge Machining (EDM) damage of the motor bearings is a relevant issue caused by the common-mode (CM) voltages of the inverter stage. The high effective switching frequency of the 3L-FCC and the possibility of CM voltage canceling in the 2L-SSC facilitate mitigation of EDM by means of CM chokes, whereby a substantially smaller CM choke with lower losses suffices for the 2L-SSC; based on exemplary designs, the 2L-SSC features only about 75% of the total volume and 85% of the nominal losses of the 3L-FCC. If, alternatively, motor-friendliness is maximized by including DC-referenced sine-wave output filters, the 3L-FCC’s higher effective switching frequency and the 2L-SSC’s need for two sets of filters due to the dual-winding-set motor change the outcome. In this case, the 3L-FCC features only about 60% of the volume and only about 55% of the 2L-SSC’s nominal losses.

Publications 1 - 10 of 35

Spasoje Miric

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