A high efficiency microturbine concept

There is a growing trend towards decentralized electricity and heat production throughout the world. Reciprocating engines and gas turbines have an essential role in the global decentralized energy markets and any improvement in their electrical efficiency has a significant impact from the environmental and economic viewpoints. This paper introduces an inter-cooled and recuperated two-shaft microturbine at 500 kW electric output range. The microturbine is optimized for a realistic combination of the turbine inlet temperature, the recuperation rate and the pressure ratio. The new microturbine design aims to achieve significantly increased performance within the range of microturbines and even competing with the efficiencies achieved in large industrial gas turbines. The simulated electrical efficiency is 45%. Improving the efficiency of combined heat and power (CHP) systems will significantly decrease the emissions and operating costs of decentralized heat and electricity production. Cost-effective, compact and environmentally friendly micro-and small-scale CHP turbine systems with high electrical efficiency will have an opportunity to successfully compete against reciprocating engines, which today are used in heat and power generation all over the world and manufactured in large production series. This paper presents a small-scale gas turbine process, capable of competing with reciprocating engine in terms of electrical efficiency.

Performance and scalability of isolated DC-DC converter topologies in low voltage, high current applications

Fuel cells are a promising alternative for clean and efficient energy production. A fuel cell is probably the most demanding of all distributed generation power sources. It resembles a solar cell in many ways, but sets strict limits to current ripple, common mode voltages and load variations. The typically low output voltage from the fuel cell stack needs to be boosted to a higher voltage level for grid interfacing. Due to the high electrical efficiency of the fuel cell, there is a need for high efficiency power converters, and in the case of low voltage, high current and galvanic isolation, the implementation of such converters is not a trivial task. This thesis presents galvanically isolated DC-DC converter topologies that have favorable characteristics for fuel cell usage and reviews the topologies from the viewpoint of electrical efficiency and cost efficiency. The focus is on evaluating the design issues when considering a single converter module having large current stresses. The dominating loss mechanism in low voltage, high current applications is conduction losses. In the case of MOSFETs, the conduction losses can be efficiently reduced by paralleling, but in the case of diodes, the effectiveness of paralleling depends strongly on the semiconductor material, diode parameters and output configuration. The transformer winding losses can be a major source of losses if the windings are not optimized according to the topology and the operating conditions. Transformer prototyping can be expensive and time consuming, and thus it is preferable to utilize various calculation methods during the design process in order to evaluate the performance of the transformer. This thesis reviews calculation methods for solid wire, litz wire and copper foil winding losses, and in order to evaluate the applicability of the methods, the calculations are compared against measurements and FEM simulations. By selecting a proper calculation method for each winding type, the winding losses can be predicted quite accurately before actually constructing the transformer. The transformer leakage inductance, the amount of which can also be calculated with reasonable accuracy, has a significant impact on the semiconductor switching losses. Therefore, the leakage inductance effects should also be taken into account when considering the overall efficiency of the converter. It is demonstrated in this thesis that although there are some distinctive differences in the loss distributions between the converter topologies, the differences in the overall efficiency can remain within a range of a few percentage points. However, the optimization effort required in order to achieve the high efficiencies is quite different in each topology. In the presence of practical constraints such as manufacturing complexity or cost, the question of topology selection can become crucial.

Energy efficiency of glassmaking production

Master’s thesis Energy efficiency of glassmaking production gives description of glassmaking production and possible energy saving measures. Due to the high electricity and fuel prices the problem of rational energy utilization rises sharply. In addition the environmental issues also require a great attention. This work represented the feasible increasing of the furnace efficiency as the most productive activity. Thesis also provides a detail description of utilizing waste heat boiler. Also possible boiler characteristics are calculated and represented at the end of the thesis. As well as brief description of the feasibility of using this method of energy saving. The solution of this problem has a huge importance. Due to the increasing of energy costs and limits of raw materials, glassmaking industry should overcome on high efficiency operation mode. Especially, if such measures is making a significant contribution in the safety of environment.

Hiiliteräspalkin kuitulaserhitsaus

Hitsaavassa teollisuudessa kilpailukyvyn säilyttäminen ja mahdollinen parantaminen edellyttää hitsauksen tehokkuuden nostoa. Laserhitsauksen nopeus, tarkkuus, tasainen laatu ja aikaansaatava syvä tunkeuma ovatkin vakiinnuttaneet menetelmän vankan aseman tehokkaana valmistusmenetelmänä. Sähkön ja heliumin hinnan nousu ovat pakottaneet teollisuuden miettimään entistä tehokkaampien ja ympäristöystävällisempien laserlähteiden hankkimista. Kuitulaserin korkea hyötysuhde, hyvä säteenlaatu, suuri teho ja matalat käyttökustannukset ovat herättäneet kiinnostusta laserhitsaavassa teollisuudessa. Diplomityössä keskityttiin kuitulaserhitsauksen soveltamiseen. Työn tavoitteena oli parantaa kuitulaserhitsausmenetelmän ymmärrystä ja saada käsitys siitä, miten valitaan hitsausparametrien arvot, ja soveltuuko kuitulaser teolliseen tuotantoon. Tutkimuksessa pyrittiin löytämään peruskokeilla optimaaliset hitsausparametrit, joilla syntyy hyvin tunkeutunut, vähän huokosia sisältävä, ja ulkoisesti laadukas hitsi, sekä optimaalinen hitsin tunkeumaprofiili. Lopuksi hitsausparametreja testattiin tuotteen hitsauksessa. Kuitulaser soveltuu erinomaisesti hiiliteräksen hitsaukseen ja hyvin erikoislujien terästen hitsaukseen, kun teräksen hiili- ja rikkipitoisuudet ovat matalia. Sillä on laaja parametrialue. Yleisimmät hitsausvirheet ovat vajaa hitsautumissyvyys ja huokoset. Tässä diplomityössä keskityttiin etsimään yhdelle valmistettavalle tuotteelle optimaaliset kuitulaserhitsausparametrit. Kuitulaserin laser- ja prosessiparametrien vaikutusta hitsiin ei ole juurikaan tutkittu. Diplomityön kokeiden perusteella olisi hyvä tehdä eri materiaalien jatkotutkimusta railonvalmistuksen, kuten liitoksen oksidikerroksen ja ilmaraon sekä suojakaasun, vaikutuksesta hitsiin. Kuitulaserin hyvä säteenlaatu ja muut laser-parametrit ovat tuoneet mukanaan prosessiin uusia ilmiöitä, joita on syytä tutkia lisää.

Modeling and Synthesis of Tracking Control for the Belt Drive System

Usingof belt for high precision applications has become appropriate because of the rapid development in motor and drive technology as well as the implementation of timing belts in servo systems. Belt drive systems provide highspeed and acceleration, accurate and repeatable motion with high efficiency, long stroke lengths and low cost. Modeling of a linear belt-drive system and designing its position control are examined in this work. Friction phenomena and position dependent elasticity of the belt are analyzed. Computer simulated results show that the developed model is adequate. The PID control for accurate tracking control and accurate position control is designed and applied to the real test setup. Both the simulation and the experimental results demonstrate that the designed controller meets the specified performance specifications.

Permanent magnet synchronous motor for industrial inverter applications - analysis and design

During the latest few years the need for new motor types has grown, since both high efficiency and an accurate dynamic performance are demanded in industrial applications. For this reason, new effective control systems such as direct torque control (DTC) have been developed. Permanent magnet synchronous motors (PMSM) are well suitable for new adjustable speed AC inverter drives, because their efficiency and power factor are not depending on the pole pair number and speed to the same extent as it is the case in induction motors. Therefore, an induction motor (IM) with a mechanical gearbox can often be replaced with a direct PM motor drive. Space as well as costs will be saved, because the efficiency increases and the cost of maintenance decreases as well. This thesis deals with design criterion, analytical calculation and analysis of the permanent magnet synchronous motor for both sinusoidal air-gap flux density and rectangular air-gapflux density. It is examined how the air-gap flux, flux densities, inductances and torque can be estimated analytically for salient pole and non-salient pole motors. It has been sought by means of analytical calculations for the ultimate construction for machines rotating at relative low 300 rpm to 600 rpm speeds, which are suitable speeds e.g. in Pulp&Paper industry. The calculations are verified by using Finite Element calculations and by measuring of prototype motor. The prototype motor is a 45 kW, 600 rpm PMSM with buried V-magnets, which is a very appropriate construction for high torque motors with a high performance. With the purposebuilt prototype machine it is possible not only to verify the analytical calculations but also to show whether the 600 rpm PMSM can replace the 1500 rpm IM with a gear. It can also be tested if the outer dimensions of the PMSM may be the same as for the IM and if the PMSM in this case can produce a 2.5 fold torque, in consequence of which it may be possible to achieve the same power. The thesis also considers the question how to design a permanent magnet synchronous motor for relatively low speed applications that require a high motor torqueand efficiency as well as bearable costs of permanent magnet materials. It is shown how a selection of different parameters affects the motor properties. Key words: Permanent magnet synchronous motor, PMSM, surface magnets, buried magnets

A comparative performance study of four-pole induction motors and synchronous reluctance motors in variable speed drives

Design aspects of the Transversally Laminated Anisotropic (TLA) Synchronous Reluctance Motor (SynRM) are studied and the machine performance analysis compared to the Induction Motor (IM) is done. The SynRM rotor structure is designed and manufactured for a30 kW, four-pole, three-phase squirrel cage induction motor stator. Both the IMand SynRM were supplied by a sensorless Direct Torque Controlled (DTC) variablespeed drive. Attention is also paid to the estimation of the power range where the SynRM may compete successfully with a same size induction motor. A technicalloss reduction comparison between the IM and SynRM in variable speed drives is done. The Finite Element Method (FEM) is used to analyse the number, location and width of flux barriers used in a multiple segment rotor. It is sought for a high saliency ratio and a high torque of the motor. It is given a comparison between different FEM calculations to analyse SynRM performance. The possibility to take into account the effect of iron losses with FEM is studied. Comparison between the calculated and measured values shows that the design methods are reliable. A new application of the IEEE 112 measurement method is developed and used especially for determination of stray load losses in laboratory measurements. The study shows that, with some special measures, the efficiency of the TLA SynRM is equivalent to that of a high efficiency IM. The power factor of the SynRM at rated load is smaller than that of the IM. However, at lower partial load this difference decreases and this, probably, brings that the SynRM gets a better power factor in comparison with the IM. The big rotor inductance ratio of the SynRM allows a good estimating of the rotor position. This appears to be very advantageous for the designing of the rotor position sensor-less motor drive. In using the FEM designed multi-layer transversally laminated rotor with damper windings it is possible to design a directly network driven motor without degrading the motorefficiency or power factor compared to the performance of the IM.

Induction motor versus permanent magnet synchronous motor in motion control applications: a comparative study

High dynamic performance of an electric motor is a fundamental prerequisite in motion control applications, also known as servo drives. Recent developments in the field of microprocessors and power electronics have enabled faster and faster movements with an electric motor. In such a dynamically demanding application, the dimensioning of the motor differs substantially from the industrial motor design, where feasible characteristics of the motor are for example high efficiency, a high power factor, and a low price. In motion control instead, such characteristics as high overloading capability, high-speed operation, high torque density and low inertia are required. The thesis investigates how the dimensioning of a high-performance servomotor differs from the dimensioning of industrial motors. The two most common servomotor types are examined; an induction motor and apermanent magnet synchronous motor. The suitability of these two motor types indynamically demanding servo applications is assessed, and the design aspects that optimize the servo characteristics of the motors are analyzed. Operating characteristics of a high performance motor are studied, and some methods for improvements are suggested. The main focus is on the induction machine, which is frequently compared to the permanent magnet synchronous motor. A 4 kW prototype induction motor was designed and manufactured for the verification of the simulation results in the laboratory conditions. Also a dynamic simulation model for estimating the thermal behaviour of the induction motor in servo applications was constructed. The accuracy of the model was improved by coupling it with the electromagnetic motor model in order to take into account the variations in the motor electromagnetic characteristics due to the temperature rise.

Hyvän hyötysuhteen moottorilla saavutettavat säästöt

Työssä on tutkittu milloin kannattaa hankkia hyvän hyötysuhteen moottori tavallisen moottorin sijasta. Työ on tehty UPM-Kymmene Oyj:n Kaukaan tehtailla. Ensiksi selvitettiin millaisessa kuormassa moottorit Kaukaan sellu- ja paperitehtaalla käyvät. Sen jälkeen työssä laskettiin, milloin hyvän hyötysuhteen moottorilla saavutetaan niin suuret säästöt, että se kannattaa hankkia. Hyvän hyötysuhteen moottorin hankinnalle laskettiin myös takaisinmaksuaika ja sisäinen korko. Herkkyysanalyysillä tutkittiin muuttuuko moottori-investoinnin kannattavuus, kun hankkeen kriittisiä tekijöitä muutetaan. Oleellista moottori-investoinnissa on moottoreiden hinta ja hyötysuhde-ero sekä moottorin käyntiaika ja kuormitusprosentti. Työn perusteella selvisi, että ainakin pienet moottorit kannattaa hankkia hyvän hyötysuhteen moottoreina.

Energiankäytön kartoitus Lappeenrannan sementtitehtaalla.

Diplomityön tavoitteena oli kartoittaa Finnsementti Oy:n Lappeenrannan sementtitehtaan energiankäyttöä ja etsiä potentiaalisia energiansäästökohteita. Diplomityö liittyy Kauppa- ja teollisuusministeriön ja Teollisuuden ja Työnantajain Keskusliiton väliseen teollisuuden energiankäytön tehostamiseen tähtäävään puitesopimukseen, johon Finnsementti Oy on liittynyt. Diplomityön teoriaosassa tutustutaan sementin kemiaan raaka-aineista valmiisiin tuotteisiin. Lisäksi kartoitetaan sementtiteollisuuden energiansäästömahdollisuuksia laite-hankintojen ja prosessin optimointinnin kannalta. Työssä tutustutaan sementin-valmistuksessa käytettäviin laitteistoihin ja selvitetään niiden teknistä kehitystä ja energiaasäästäviä ratkaisuja. Kokeellinen osuus alkaa yksityiskohtaisella kuvauksella Lappeenrannan sementtitehtaan valmistusprosessista. Kokeellisessa osassa tutustutaan tehtaan energiankulutukseen sähkön ja polttoaineen muodossa. Lisäksi käsitellään paineilmaa ja vettä. Sähkön osalta kokeellinen osa sisältää sähkönkulutuksen historian ja sähkönjakeluverkon selvityksen lisäksi tehtaalla käytössä olevien luokittimien tehokkuustarkasteluita sähkönkulutuksen kannalta. Polttoaineen osalta diplomityö sisältää sementtiuunien energiataseiden mittaukset ja tulosten laskemisen sekä Excel-pohjaisen menetelmän kehittämisen energiataseiden laskemiseksi tulevaisuudessa. Paineilman ja veden osalta selvitetään niiden kulutusta tehtaalla ja lasketaan paineilmalle teoreettinen ominaissähkönkulutus. Luokittimien tehokkuustarkastelujen osalta havaittiin raakamyllyn luokittimen erottelu-terävyyden olevan huono verrattuna nykyaikaisiin korkeatehokkuusluokittimiin. Sementtimyllyjen luokittimien toiminnasta ei havaittu merkittäviä ongelmia. Energia-taseiden tuloksina havaittiin Lappeenrannan sementtitehtaan sementtiuunien edustavan vanhentunutta sementinvalmistustekniikkaa. Molempien uunien savukaasukanavien vuotoilmojen määrien havaittiin olevan suuret. Energiataloutta pystyttäisiin parantamaan mm. uusilla polttimilla, jolloin lämmittämättömän ensiöilman osuutta saataisiin pienentymään ja polttoaineen polttoa tehostumaan. Paineilman suhteen havaittiin kuumailman paineenalennuksen aiheuttavan turhia energiahäviöitä.

Energiansiirtoketjun energiatehokkuus

Tämän työn tavoitteena oli tarkastella energiansiirtoketjun kokonaisenergiatehokkuutta, alkaen polttoaineesta ja päättyen sähköenergian loppukäyttäjään. Tarkasteltava energiansiirtoketju alkaa polttoaineen tuotannosta ja siirrosta. Tämän jälkeen tulee sähköenergian tuottaminen, siirtäminen, jakelu ja loppukäyttö. Sähköntuotannon osalta tarkasteltiin myös vesivoimaa ja tuulivoimaa, jolloin energiansiirtoketjusta jää polttoaineen tuotannon ja siirron häviöt pois. Työn pääpaino kohdistui sähköenergian tuotannon, siirron, jakelun ja loppukäytön energiatehokkuuksien tarkastelemiseen. Työssä selvitettiin myös tulevaisuuden näkymiä, miten hyötysuhteita saataisiin parannettua eri osa-alueilla uusilla tekniikoilla ja käyttötottumuksilla. Loppukäyttäjä saa polttoaineen energiasta hyödyksi noin neljänneksen. Suurimmat häviöt syntyvät sähköenergian tuotannossa, lukuun ottamatta vesivoimalaitoksia, joiden hyötysuhde on erittäin korkea.

Position sensorless electrically excited synchronous motor drive for industrial use based on direct flux linkage and torque control

Synchronous machines with an AC converter are used mainly in large drives, for example in ship propulsion drives as well as in rolling mill drives in steel industry. These motors are used because of their high efficiency, high overload capacity and good performance in the field weakening area. Present day drives for electrically excited synchronous motors are equipped with position sensors. Most drives for electrically excited synchronous motors will be equipped with position sensors also in future. This kind of drives with good dynamics are mainly used in metal industry. Drives without a position sensor can be used e.g. in ship propulsion and in large pump and blower drives. Nowadays, these drives are equipped with a position sensor, too. The tendency is to avoid a position sensor if possible, since a sensor reduces the reliability of the drive and increases costs (latter is not very significant for large drives). A new control technique for a synchronous motor drive is a combination of the Direct Flux Linkage Control (DFLC) based on a voltage model and a supervising method (e.g. current model). This combination is called Direct Torque Control method (DTC). In the case of the position sensorless drive, the DTC can be implemented by using other supervising methods that keep the stator flux linkage origin centered. In this thesis, a method for the observation of the drift of the real stator flux linkage in the DTC drive is introduced. It is also shown how this method can be used as a supervising method that keeps the stator flux linkage origin centered in the case of the DTC. In the position sensorless case, a synchronous motor can be started up with the DTC control, when a method for the determination of the initial rotor position presented in this thesis is used. The load characteristics of such a drive are not very good at low rotational speeds. Furthermore, continuous operation at a zero speed and at a low rotational speed is not possible, which is partly due to the problems related to the flux linkage estimate. For operation in a low speed area, a stator current control method based on the DFLC modulator (DMCQ is presented. With the DMCC, it is possible to start up and operate a synchronous motor at a zero speed and at low rotational speeds in general. The DMCC is necessary in situations where high torque (e.g. nominal torque) is required at the starting moment, or if the motor runs several seconds at a zero speed or at a low speed range (up to 2 Hz). The behaviour of the described methods is shown with test results. The test results are presented for the direct flux linkage and torque controlled test drive system with a 14.5 kVA, four pole salient pole synchronous motor with a damper winding and electric excitation. The static accuracy of the drive is verified by measuring the torque in a static load operation, and the dynamics of the drive is proven in load transient tests. The performance of the drive concept presented in this work is sufficient e.g. for ship propulsion and for large pump drives. Furthermore, the developed methods are almost independent of the machine parameters.

Salient Pole Synchronous Machine Modelling in an Industrial Direct Torque Controlled Drive Application

Synchronous motors are used mainly in large drives, for example in ship propulsion systems and in steel factories' rolling mills because of their high efficiency, high overload capacity and good performance in the field weakening range. This, however, requires an extremely good torque control system. A fast torque response and a torque accuracy are basic requirements for such a drive. For large power, high dynamic performance drives the commonly known principle of field oriented vector control has been used solely hitherto, but nowadays it is not the only way to implement such a drive. A new control method Direct Torque Control (DTC) has also emerged. The performance of such a high quality torque control as DTC in dynamically demanding industrial applications is mainly based on the accurate estimate of the various flux linkages' space vectors. Nowadays industrial motor control systems are real time applications with restricted calculation capacity. At the same time the control system requires a simple, fast calculable and reasonably accurate motor model. In this work a method to handle these problems in a Direct Torque Controlled (DTC) salient pole synchronous motor drive is proposed. A motor model which combines the induction law based "voltage model" and motor inductance parameters based "current model" is presented. The voltage model operates as a main model and is calculated at a very fast sampling rate (for example 40 kHz). The stator flux linkage calculated via integration from the stator voltages is corrected using the stator flux linkage computed from the current model. The current model acts as a supervisor that prevents only the motor stator flux linkage from drifting erroneous during longer time intervals. At very low speeds the role of the current model is emphasised but, nevertheless, the voltage model always stays the main model. At higher speeds the function of the current model correction is to act as a stabiliser of the control system. The current model contains a set of inductance parameters which must be known. The validation of the current model in steady state is not self evident. It depends on the accuracy of the saturated value of the inductances. Parameter measurement of the motor model where the supply inverter is used as a measurement signal generator is presented. This so called identification run can be performed prior to delivery or during drive commissioning. A derivation method for the inductance models used for the representation of the saturation effects is proposed. The performance of the electrically excited synchronous motor supplied with the DTC inverter is proven with experimental results. It is shown that it is possible to obtain a good static accuracy of the DTC's torque controller for an electrically excited synchronous motor. The dynamic response is fast and a new operation point is achieved without oscillation. The operation is stable throughout the speed range. The modelling of the magnetising inductance saturation is essential and cross saturation has to be considered as well. The effect of cross saturation is very significant. A DTC inverter can be used as a measuring equipment and the parameters needed for the motor model can be defined by the inverter itself. The main advantage is that the parameters defined are measured in similar magnetic operation conditions and no disagreement between the parameters will exist. The inductance models generated are adequate to meet the requirements of dynamically demanding drives.

Hybrid LC Filter for Power Electronic Drives: Theory and Implementation

Power electronic converter drives use, for the sake of high efficiency, pulse-width modulation that results in sequences of high-voltage high-frequency steep-edged pulses. Such a signal contains a set of high harmonics not required for control purposes. Harmonics cause reflections in the cable between the motor and the inverter leading to faster winding insulation ageing. Bearing failures and problems with electromagnetic compatibility may also result. Electrical du/dt filters provide an effective solution to problems caused by pulse-width modulation, thereby increasing the performance and service life of the electrical machines. It is shown that RLC filters effectively decrease the reflection phenomena in the cable. Improved (simple, but effective) solutions are found for both differential- and common-mode signals; these solutions use a galvanic connection between the RLC filter star point and the converter DC link. Foil chokes and film capacitors are among the most widely used components in high-power applications. In actual applications they can be placed in different parts of the cabinet. This fact complicates the arrangement of the cabinet and decreases the reliability of the system. In addition, the inductances of connection wires may prevent filtration at high frequencies. This thesis introduces a new hybrid LC filter that uses a natural capacitance between the turns of the foil choke based on integration of an auxiliary layer into it. The main idea of the hybrid LC filter results from the fact that both the foil choke and the film capacitors have the same roll structure. Moreover, the capacitance between the turns (“intra capacitance”) of the foil inductors is the reason for the deterioration of their properties at high frequencies. It is shown that the proposed filter has a natural cancellation of the intra capacitance. A hybrid LC filter may contain two or more foil layers isolated from each other and coiled on a core. The core material can be iron or even air as in the filter considered in this work. One of the foils, called the main foil, can be placed between the inverter and the motor cable. Other ones, called auxiliary foils, may be connected in star to create differential-mode noise paths, and then coupled to the DC link midpoint to guarantee a traveling path, especially for the common-mode currents. This way, there is a remarkable capacitance between the main foil and the auxiliary foil. Investigations showed that such a system can be described by a simple equivalent LC filter in a wide range of frequencies. Because of its simple hybrid construction, the proposed LC filter can be a cost-effective and competitive solution for modern power drives. In the thesis, the application field of the proposed filter is considered and determined. The basics of hybrid LC filter design are developed further. High-frequency behaviour of the proposed filter is analysed by simulations. Finally, the thesis presents experimental data proving that the hybrid LC filter can be used for du/dt of PWM pulses and reduction of common-mode currents.

Täystehokonvertterin tehohäviöt ja hyötysuhde

Diplomityössä perehdytään tuuliturbineissa käytettyjen täystehokonvertterien tehohäviöihin ja hyötysuhteeseen. Täystehokonvertterissa generaattorin tuottama sähköteho tasasuunnataan hyvällä hyötysuhteella aktiivisella geenraattorisillalla konvertterin välipiiriin ja edelleen vaihtosuunnataan aktiivisella verkkovaihtosuuntaajasillalla siirtoverkkoon. Työn tarkoituksena on antaa yleiskuva tehohäviöiden jakautumisesta ja yksinkertaistaa niiden laskentaa. Häviömekanismit ja häviöiden määräytyminen esitellään pääkomponenttitasolla. Tehohäviöiden osalta keskitytään erityisesti muuntajateräksestä valmistettujen sinisuotimien ja du/dt-suotimien rautahäviöihin. Ongelmana rautahäviöiden määrittämisessä on korkeilla taajuuksilla tapahtuvat häviöt, joiden laskentaan ei ole yleensä saatavilla tarvittavia materiaaliparametrejä. Tehohäviöiden laskentaa varten toteutettu laskentasovellus on esitelty periaatteellisina vuokaavioina ja sovelluksella saatavia tuloksia on esitetty ja vertailtu mitattuihin tuloksiin.