Publications by Miroslav Markovic

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In order to control the speed and/or position of permanent magnet (PM) motors, they require position sensors. Basically, the auto-commutation needs 3 sensors for a 3-phase motor. In micro-motors, as there is no space for the sensors, self-sensing must be u ...

The paper presents a completely analytical formula to determine the phase back emf of a slotted BLDC motor with interior or exterior rotor and parallel or radial permanent magnet (PM) magnetization and concentrated winding. The formula is based on integrat ...

In order to create a new solar aircraft totally powered by the sun, a new method able to handle such a complex system must be developed. The project aim is to make a round-the-world flight in so as to promote the sustainable development. The aircraft power train will consist of solar cells placed on the wings, the energy storage system, the energy management electronics, the brushless DC motor and propellers. This paper presents the method to optimize the motor together with the propellers, to save the maxi

The paper presents a methodology to determine the coefficient of the natural convection for the surface of a small electric motor. The theory of natural convection is applied to obtain analytical formulas, and the radiation is incorporated in the model. The measurements are performed on a simple motor model, a copper cylinder with a resistance inside acting as a heater. The obtained results match the theoretical predictions. © 2006 IEEE.

We present an exact model for determining the cogging torque in a brushless DC (BLDC) motor. It is based on the conformal mapping (CM) method, by which the motor configuration is transformed to a configuration where the magnetic field can be determined. Then, by integrating the field over the stator surface, the cogging torque is determined. By varying some motor parameters, which is easy to do, an optimal configuration with the minimal cogging torque is obtained. We have confirmed the results by the finite

We present an application of the conformal mapping (CM) method to determine the magnetic field and force in an electromechanical actuator. First, we show how to find, using a special type of CM known as the Schwarz-Christoffel mapping, the magnetic field in such a configuration. Then, we integrate the field in order to determine the force acting on the actuator moving part. The results are verified by a finite-element method.

This paper presents an approach to design a contactless energy-transfer system to supply desktop computer peripherals. Energy is transferred using coreless transformers from an array of primary coils (placed on a table) to one or several secondary coils (placed under the peripheral). Knowing the geometrical structure of the coils of a coreless transformer, accurate calculations allow predicting the power that can be transferred to a load. By applying these calculations to one basic energy-transfer cell, it

This paper presents an approach to design a contactless energy transfer system to supply desktop computer peripherals. Energy is transferred using coreless transformers from an array of primary coils (placed on a table) to one or several secondary coils (placed under the peripheral). Knowing the geometrical structure of the coils of a coreless transformer, accurate calculations allow to predict the power that can be transferred to a load. By applying these calculations to one basic energy transfer cell, it

This paper introduces a promising technique, called the first-pulse technique, for detecting the rotor position of a brushless DC motor at standstill. The technique is based on the B-H hysteresis characteristics of the stator iron. Depending on the rotor p ...

An original analytical formula for the torque/emf constant of a slotless brushless DC (BLDC) motor is presented. It is obtained by solving and integrating the permanent magnet field. In addition, formulas for the both stator and rotor iron fields are derived, in order to estimate the saturation level and losses. The results are verified using a FEM simulation. © 2006 IEEE.

We present an analytical solution for the induced eddy currents and the corresponding losses generated in the rotor of a slotless permanent magnet (PM) motor. The field excitation is a current layer placed at the stator interior surface. The solution is ba ...

This paper describes a linear motor optimization based on an analytical model. The studied motor, also called "ironless", consists of an iron core U shape with permanent magnets on each side, between which the coils can move. The glider which supports the coils is made of a non-ferromagnetic composite material, like epoxy. For this reason this type of motor has a small force density, but on the other hand this motor has a small moving mass, which allows high accelerations. The goal is to show that various o

The paper presents a completely analytical method for determining the eddy currents in a cylindrical configuration. The configuration consists of a cylindrical permanent magnet rotating inside a conducting hollow cylinder (stator). The solution is obtained ...

The paper presents a completely analytical solution for the magnetic field, the induced eddy currents and corresponding losses in a toroidal laminated core with a rectangular cross section. The diffusion equation is analytically solved using a separation o ...

We present a new, completely original exact method to determine the permeance between two opposing iron teeth. This configuration is important because it is often encountered in electrical machines and apparatus. The method is based on conformal mapping. T ...

The paper presents a method to determine hysteresis losses in synchronous permanent magnet (M) slotless motors. The method comprises four steps: (1) experimental determination of the B-H loop, () analytical modeling of the B-H loop by applying different models, (3) analytical modeling of the hysteresis losses, and (4) determination of the hysteresis losses in a synchronous PM motor, and results verification using an experiment and an FEM software. This paper also presents an innovative and simple way to tak

The aim of the European project Nephron+ is the design of a wearable artificial kidney device. This paper is focused on the design of the corresponding ultralow-hemolysis continuous-operation blood pump. Accurate specifications and operating principle of t ...

This paper focuses on the maximization of the torque-to-weight ratio of permanent magnet synchronous motors (PMSM) using a topology optimization method. It aims at finding the optimal design that either maximizes the torque for a given weight or minimizes the weight for a required torque. The analysis presented in this paper besides considers radial and tangential permanent magnets. The paper shows that the optimization always leads to the same optimal motor topology, which is scaled to achieve the required

In the analysis of squeeze film haptic tactile feedback actuators, attention is focused on establishing an empirical model of the force generated on the user's finger. The model is based on finite-element simulations which take into account the real motion ...

This paper introduces a promising technique for detecting the rotor position of a PM motor at standstill. The technique is based on the B-H hysteresis characteristics of the stator iron. Depending on the rotor position, a very particular phenomenon related to B-H hysteresis appears. This phenomenon permits to detect the electrical position of a non-salient rotor.

Miroslav Markovic

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Self-Sensing Methods from MEMs to Solar Aircraft Motors

An analytical formula for the back emf of a slotted BLDC motor

Brushless DC motor optimization process - Choice between standard or straight tooth shape

Determination of the thermal convection coefficient for a small electric motor

Reducing the cogging torque in brushless DC motors by using conformal mappings

Analyzing an electromechanical actuator by Schwarz-Christoffel mapping

Design of a Contactless Energy-Transfer System for Desktop Peripherals

Design of a contactless energy transfer system for desktop peripherals

First pulse technique for brushless DC motor standstill position detection based on iron B-H hysteresis

Analytical formula for the torque/emf constant of a slotless BLDC motor

An analytical solution for the rotor eddy current losses in a slotless PM motor: the case of current layer excitation

Linear motor optimization using an analytical model

An analytical determination of eddy-current losses in a configuration with a rotating permanent magnet

Eddy current power losses in a toroidal laminated core with rectangular cross section

An exact formula for "tooth-to-tooth" permeance

Modeling of Hysteresis Losses Applied to Slotless Permanent Magnet Motors

Design and Optimization of A Blood Pump for A Wearable Artificial Kidney Device

Torque-to-weight Ratio Maximization in PMSM Using Topology Optimization

Empirical Modeling of a Squeeze Film Haptic Actuator

Exploitation of a new iron B-H phenomenon for the standstill position detection of PM motors