Technical LibraryApplication Catalog

Iron loss analysis / Loss analysis
185 - Analysis of Stray Loss in a Large Transformer185 - Analysis of Stray Loss in a Large Transformer
Module:FQ,LS2013-12-17
Transformers are made to be used long-term, so it has become an important design policy to control running costs from losses. These losses include copper loss in the coil and iron loss in the core. In high-capacity transformers, however, there is also stray loss in the tank from flux leakage from the core. Stray loss is not only the total loss value, it also poses the risk of generating heat locally so there is a need to check loss distribution.
Predicting these losses and the heat that they generate is a vital component of transformer design, but it is difficult to estimate them from desktop calculations, so evaluations and detailed analyses using the finite element method (FEM) are indispensable.
This note obtains loss distribution for each component in drive condition and checks local overheating.
181 - Analysis of SR Motor Drive Characteristics181 - Analysis of SR Motor Drive Characteristics
Module:DP,LS2013-01-23
With the skyrocketing prices of rare earth magnets, expectations have been rising for SR (switched reluctance) motors because they have a motor format that does not use permanent magnets. SR motors have a simple structure that can achieve solid performance at a low price. However, torque generation depends only upon the saliency between the stator and rotor, so torque variations are extremely large and cause vibration and noise, meaning that the use applications are limited. On the other hand, because of the skyrocketing prices of rare earth metals, the improvement in current control technology, the possibility of optimized designs thanks to magnetic field analysis, and the rising ability to reduce challenges, SR motors are being re-examined.
SR motors sometimes drive while changing switch timing in accordance with rotation speed so it is useful to understand properties such as torque, current and iron loss in accordance with revolution speed.
This example presents how to confirm drive characteristics such as torque, loss, and efficiency in a motor when its switch timing changes for each rotation speed.
177 - Torque Characteristic Analysis of a Three Phase Induction Motor177 - Torque Characteristic Analysis of a Three Phase Induction Motor
Module:DP,LS2012-08-31
An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, which exerts force on the rotor in the rotational direction and causes it to spin. Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction and are small, light, affordable, and maintenance-free.
It is possible to drive an induction motor so that its slip is constant by adjusting the voltage or current against load variations. When this happens, each characteristic changes with influence from magnetic saturation and leakage flux because of the excitation variations in a specific slip.
This Application Note explains how to obtain the torque characteristics in an induction motor when the current amplitude has been changed in a specific slip.
176 - Drive Characteristic Analysis of a Three-Phase Induction Motor176 - Drive Characteristic Analysis of a Three-Phase Induction Motor
Module:DP,LS2012-08-31
An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, which exerts force on the rotor in the rotational direction and causes it to spin. Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction and are small, light, affordable, and maintenance-free.
In an induction motor, the current induced by the auxiliary conductor exerts a large influence on its characteristics. It also causes strong magnetic saturation in the vicinity of the gap, in particular. This is why a magnetic field analysis based on the finite element method (FEM) is useful when investigating the motor's characteristics for a design study.
This Application Note explains how to confirm drive characteristics such as torque, loss, and efficiency in an induction motor when its rotation speed changes.
167 - Iron Loss Analysis of a Three Phase Induction Motor167 - Iron Loss Analysis of a Three Phase Induction Motor
Module:DP,LS2013-06-27
An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, which produces force in the rotational direction.
Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction without parts that experience wear from abrasion, and can be used simply by connecting them to a power source.
Improved efficiency in induction motors is an important theme. Iron loss, a cause of lower efficiency along with primary and secondary copper loss, must be reduced in order to improve efficiency. The relative importance of iron loss tends to grow especially with higher rotations due to the inverter drive, so it is helpful to estimate the complex iron loss distribution inside the core.
This Application Note presents an example of how to find the iron loss in the stator core and rotor core at a rotation speed of 3,300 r/min.
157 - Analysis of Eddy Currents in an IPM Motor Using the Gap Flux Boundary157 - Analysis of Eddy Currents in an IPM Motor Using the Gap Flux Boundary HOT!
Module:DP,FQ2014-02-27
It is becoming increasingly common for permanent magnet motors to use rare earth magnets in order to achieve higher output density because they have a high energy product. Neodymium rare earth magnets have a high electric conductivity because they contain a great deal of iron, so when a varying magnetic field is applied to them they produce joule loss from eddy currents. IPM structure adoption and field weakening controls have become prevalent in recent years in order to allow faster rotation. This has led to an increase in the frequencies and fluctuation ranges of the varying fields applied to magnets, resulting in a corresponding increase in joule losses. By dividing the magnet like one would a laminated core to control eddy currents, one can obtain a method of raising the apparent electric conductivity while lowering the eddy currents. Armature reactions in the stator occur before the eddy currents produced in the magnet, so the eddy currents are determined by: The slot geometry of the stator core, the geometry of the rotor, the nonlinear magnetic properties of the core material, and the current waveform that flows through the coil.
In order to examine these kinds of magnet eddy currents ahead of time, one has to be precise when accounting for things like these various geometries and material properties. This is why a magnetic field simulation using the finite element method (FEM), which can account for them, would be the most effective.
This Application Note explains how to use the gap flux boundary condition to evaluate the eddy current loss in the magnet by changing the number of magnet divisions. This will make it possible to obtain effective results in a shorter period of time than with a normal transient response analysis.
148 - Loss Analysis of a Power Transformer (Flyback Converter)148 - Loss Analysis of a Power Transformer (Flyback Converter)
Module:DP,LS,TR,TS2012-08-31
A flyback converter is a well-known system for small capacity power supplies in the several-dozen W class. They are cheap and have a simple structure, so they are widely used as converters for pressurization in home appliances. In recent years there has been a trend toward making small-scale switching transformers even smaller and higher-frequency, so it is not rare to see converters using the flyback system drive 100 kHz or more.
Because of the higher frequencies and smaller scales of transformers, an important challenge of how to control their heat generation has emerged in the design process. The losses that produce heat can be separated into copper loss in the coil and iron loss in the core. Copper loss is distributed inside of the coils because of the proximity effect, which is caused by influence from the skin effect and leakage flux. This means that local heat generation in the coils becomes a problem.
Iron loss also has a complex distribution because it depends on the magnetic flux density distribution that accounts for the core's magnetic saturation, so the core's local heat generation becomes a problem as well.
A magnetic field analysis simulation based on the finite element method (FEM) can precisely evaluate the complex loss distributions of the coil and core, so it is optimal for an advance study of a switching transformer's thermal design.
146 - Analysis of Stray Loss in a Transformer146 - Analysis of Stray Loss in a Transformer
Module:FQ,HT,LS2013-06-27
Transformers are made to be used long-term, so it has become an important design policy to control running costs from losses. These losses include copper loss in the coil and iron loss in the core. In high-capacity transformers, however, there is also stray loss in the tank from flux leakage from the core. From a safety standpoint, companies want to contain the heat produced from stray losses in the tank to well below the standards required for heat resistant design because they anticipate injuries from people touching the tank itself.
Predicting these losses and the heat that they generate is a vital component of transformer design, but it is difficult to estimate them from desktop calculations, so evaluations and detailed analyses using the finite element method (FEM) are indispensible.
This Application Note explains how to obtain losses in a transformer tank and use them to evaluate the temperature distribution in each part.
142 - Press Fit Analysis of a Divided Core 142 - Press Fit Analysis of a Divided Core
Module:DP,DS,LS2013-02-28
Smaller size and higher output are being demanded of the motors used for applications such as air conditioning compressors. One production technique for achieving this is a higher lamination factor in divided cores. The stress caused by press-fitting a divided stator core into a frame is known to increase iron loss in a motor if magnetic steel sheet is used for the core.
Iron loss is affected by magnetic flux density and stress. Specifically, it increases in areas of high magnetic flux density with high frequency, and in areas of high stress. Further, the stress caused by press fitting has its own distribution, and is particularly large in the core and back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the magnetic flux density distribution, time variations, and stress distribution.
This Application Note presents how to use the Press Fit condition to model an analysis of the stress from fitting a core to a frame, and then obtain the iron loss density of an IPM motor under no load, with and without accounting for the stress.
132 - Loss Analysis of a Three-phase Transformer132 - Loss Analysis of a Three-phase Transformer
Module:FQ,LS2013-06-17
Mid- and large-sized power transformers need to be able to operate over the long term, so they are always required to control running costs from losses. Iron loss is one of the main losses in a transformer, and it can lead to temperature increases and efficiency decreases because it consumes electric power as heat in a magnetic material.
Using finite element analysis (FEA) to confirm the distribution of iron loss density makes it possible to study a transformer's local geometry during design. Further, evaluating the ratio and distribution of the iron and copper losses through FEA becomes advantageous when designing a transformer.
This note presents how to obtain the iron and copper losses of a three-phase transformer.
117 - Iron Loss Analysis of a Transformer117 - Iron Loss Analysis of a Transformer
Module:FQ,LS2013-06-17
Mid- and large-sized power transformers need to be able to operate over the long term, so they are always required to control running costs from losses. Iron loss is one of the main losses in a transformer, and it can lead to temperature increases and efficiency decreases because it consumes electric power as heat in a magnetic material.
Using finite element analysis (FEA) to confirm the distribution of iron loss density makes it possible to study a transformer's local geometry during design. Further, iron loss is divided into hysteresis loss caused by hysteresis in the core and joule loss caused by eddy currents, and analysis makes it possible to compare the relative contributions of each of these.
This Application Note presents how to obtain the iron loss and the ratio of hysteresis loss and joule loss within that iron loss for a three-phase transformer.
110 - Loss Analysis of a Choke Coil110 - Loss Analysis of a Choke Coil
Module:FQ,LS,TS2012-07-31
A choke coil is an electric component that is intended to filter high-frequency current. Measures to evaluate the heat source as well as the core iron losses that occur within the choke coil and the copper losses of the coil that decrease efficiency need to be used for this analysis.
The current generated in the choke coil has offsets caused by the skin effect, proximity effect, and leakage flux near the gap, so it is distributed both inside of and between the wires. Iron loss generated in the core is also distributed by offsets in the core's magnetic flux density. It is helpful to get tips for the design quantitatively and visually studying these detailed distributions, and an effective way of doing this is a magnetic field analysis that uses the finite element method (FEM).
This Application Note shows how to obtain the iron loss and copper loss in a choke coil.
106 - Iron Loss Analysis of a Brush Motor106 - Iron Loss Analysis of a Brush Motor
Module:DP,LS2013-06-27
Brush motors are used in many devices, particularly smaller-sized ones. With demands for energy-saving in recent years, higher efficiency is desired not only in high performance and large-scale motors used in HEVs and large appliances, but also in small-scale brush motors. To respond to these demands, it is important to reduce loss. Loss reduces efficiency directly, and also causes further reductions by increasing a device's temperature through heat generation, so it is necessary to know the amount and distribution of loss in order to create improved designs that suppress this loss. Motor loss is dominated by copper loss and iron loss, and copper loss can be more or less known from the current flowing in the coils. Iron loss, however, depends on material properties, drive conditions, and geometry, and is therefore difficult to evaluate through desktop calculation.
Magnetic analysis using the finite element method (FEM) is useful at the design stage because it can consider all electromagnetic behavior and motor geometry, and therefore makes estimation of the distribution and total amount of iron loss possible.
This note presents how to obtain the iron loss in the stator core and rotor core of a brush motor.
91 - Iron Loss Analysis of an IPM Motor Including the Effects of the Press Fitting Stress91 - Iron Loss Analysis of an IPM Motor Including the Effects of the Press Fitting Stress
Module:DP,DS,LS2013-10-28
One of the demands for IPM motors is higher efficiency over a wide range of rotation speeds in combination with motor drives, as reluctance torque can be used in addition to magnet torque. Iron loss makes up a particularly large proportion of total loss in the high rotation region, and how to make this smaller is a major design issue. Generally, IPM motor cores have laminated structures, and methods such as press fitting or shrink fitting are used to maintain them.
For motors using magnetic steel sheet for their cores, the stress generated by press fitting can increase iron loss, so it is important to take this stress into account when evaluating iron loss.
Iron loss is generated when there are magnetic-field variations in steel sheet. Also, the amount of iron loss depends on the steel sheet's iron loss properties. These iron loss properties of steel sheet become worse when it is subjected to stresses such as press fitting. The stress caused by press fitting has its own distribution, and is particularly large in the back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the stress distribution for the magnetic flux, time variation, and steel sheet.
This Application Note presents modeling the press fitting of a core and frame with the Press Fit condition and then obtaining the iron loss density of an IPM motor with and without accounting for the stress generated at that time.
90 - Analysis of the Effect of PWM on the Iron Loss of an IPM Motor90 - Analysis of the Effect of PWM on the Iron Loss of an IPM Motor
Module:DP,LS2012-07-31
Current vector controls are generally used in interior permanent magnet synchronous motors (hereinafter referred to as IPMs), and among them PWM inverters are widely utilized to create a command current. It is vital to get a good understanding of iron losses in order to raise the efficiency of an IPM motor. However, iron losses increase when power is converted by the PWM inverter because the carrier harmonic created by the PWM becomes superimposed on the current and the magnetic flux density waveform in the IPM motor's core.
There are two methods for obtaining iron loss that considers the PWM's carrier harmonics: Couple a control/circuit simulator that contains the PWM inverter with a magnetic field analysis by inputting the current waveform obtained from the simulation into the analysis, or input the actual measurements of a current into a magnetic field analysis.
This Application Note demonstrates an analysis in which a coupled analysis between a separate JMAG-RT model and a control/circuit simulator is carried out, and the effects of a carrier harmonic against an IPM motor's iron loss are displayed by inputting the current waveform calculated from the analysis.
87 - Iron Loss Analysis of an IPM Motor Including the Effect of Shrink Fitting87 - Iron Loss Analysis of an IPM Motor Including the Effect of Shrink Fitting
Module:DP,DS,LS2013-02-28
Magnetic steel sheet is used for the cores of drive motors for HEVs and EVs. This is to make them more compact, lighter, and more efficient. The main point for improving efficiency in an IPM motor's high rotation speed region is how to reduce iron loss. However, shrink fitting is used in order to strengthen the joint between frames and stator cores with laminated structure. The compressive stress generated during shrink fitting is known to increase iron loss. Therefore, it is important to account for the effects of this stress when evaluating iron loss.
Iron loss is generated when there are magnetic-field variations in steel sheet. Also, the amount of iron loss depends on the steel sheet's iron loss properties. These iron loss properties of steel sheet become worse when it is subjected to stresses such as shrink fitting. The stress caused by shrink fitting has its own distribution, and is particularly large in the back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the stress distribution for the magnetic flux, time variation, and steel sheet.
This Application Note presents how to obtain the iron loss density of an IPM motor with and without accounting for this stress.
78 - Loss Analysis of a Sheet Coil Transformer78 - Loss Analysis of a Sheet Coil Transformer
Module:FQ,LS2013-12-17
Power transformers need to be able to operate over the long term, so they are always required to control running costs from losses. Iron loss is one of the main losses in a transformer, and it can lead to temperature increases and efficiency decreases because it consumes electric power as heat in a magnetic material.
Using a finite element analysis (FEA) to display the iron loss density distribution and obtain the iron loss values in a transformer makes it possible to study the local geometry and get design feedback at the design stage.
This Application Note shows how to obtain the iron loss of a sheet coil transformer.
75 - Iron Loss Analysis of a Reactor75 - Iron Loss Analysis of a Reactor
Module:FQ,LS2013-12-17
Reactors are installed on the input or output side of inverter circuits. Because they are required for long-term operation, the ability to control running costs from losses is an important challenge for their design. Iron loss is one of the major types of losses in a reactor. It consumes electric power as heat in a magnetic body, so it causes heat to increase and efficiency to decrease in the reactor.
Using a finite element analysis (FEA) to confirm the distribution of iron loss density makes it possible to study a reactor's local geometry during its design, so it is useful in providing feedback about the design itself.
This Application Note analyzes the iron loss of a reactor.
69 - Iron Loss Analysis of an IPM Motor69 - Iron Loss Analysis of an IPM Motor
Module:DP,LS2013-10-28
Demand for higher efficiency and smaller size in motors has grown from the need to accommodate devices that incorporate miniaturization and energy efficiency in their designs. In order to meet this demand, motors have to improve their output density and reduce their losses. One type of loss commonly found in motors is iron loss, which increases drastically at high rotation speeds and high magnetic flux densities. This increase can lead to a rise in temperature and a reduction in efficiency. Consequently, it is growing more important to predict iron loss levels at the motor design stage.
Unfortunately, it is not possible to obtain iron losses accurately in studies that use the magnetic circuit method or rules of thumb. In order to obtain them accurately, one needs to find the distribution and time variations of the magnetic flux density in each part of the motor after accounting for a fine geometry and the material's nonlinear magnetic properties. Using the finite element method (FEM) is essential in order to carry out this kind of a detailed analysis.
This Application Note explains a case example that obtains the iron loss and its distribution in a permanent magnet motor.
67 - Analysis of AC Loss in a Superconductor67 - Analysis of AC Loss in a Superconductor
Module:TR2010-08-31
When superconductors are in the superconducting state, in which temperature, magnetic field and current become lower than a critical value, its electrical resistance becomes zero. Although superconducting wire rod requires a cooling system to maintain a low-temperature state, having features such as high current density and extremely low loss, it has a lot of advantages in terms of energy and environment. The electrical resistance in the superconductor becomes zero, when DC is applied, but when AC is applied, loss is caused in a superconductor. In JMAG, the AC loss in a superconductor can be obtained. This note presents the use of magnetic field analysis to obtain the AC loss in a superconductive filament.
59 - Iron Loss Analysis of an IPM Motor Accounting for a PWM -Direct Link-59 - Iron Loss Analysis of an IPM Motor Accounting for a PWM -Direct Link-
Module:DP,LS2012-08-31
Vector controls using a PWM (Pulse Width Modulation) control are commonly included in the drive circuits of high efficiency motors. A PWM control makes it possible to adjust the phase or amplitude of a current according to load and rotation speed, so they can achieve high efficiency in a wide operation range. The control frequency of a PWM is called a carrier frequency. Carrier frequencies are often used up to almost 20 kHz. To form the current waveform supplied by the PWM control, the carrier harmonic current is superimposed on the basic wave current. This carrier harmonic current applies a high-frequency magnetic field to each part of the motor. As a result, core iron loss and magnet eddy current loss are generated.
The total amount of these losses is not a dominant factor, but they can be a hindrance when trying to raise efficiency, so they need to be eliminated in the design process. In order to study these problems, both the motor's electromagnetic behavior and what kinds of controls the drive circuit performs have to be investigated.
In order to run an advance study of these phenomena in CAE, a high fidelity motor model and inverter model need to be coupled. There are three ways of accomplishing this: Directly linking with a circuit/control simulator, entering a current waveform obtained by using a JMAG-RT motor model and a circuit/control simulator, and entering actual current measurements.
In this analysis, the iron losses of the IPM motor that accounts for the carrier harmonic are obtained by directly linking to a circuit/control simulator.
58 - Efficiency Analysis of an IPM Motor58 - Efficiency Analysis of an IPM Motor
Module:DP,LS2013-10-28
An IPM motor's features are in its rotor geometry, where its magnets are embedded. When the stator's rotating magnetic field is applied in a direction that runs perpendicular to the rotor magnets (the q-axis) the motor operates like a normal SPM motor. When the current phase is displaced and the d-axis component is applied, however, the motor operates so that the magnetic fields in the rotor magnets are weakened. This is called field weakening. In an SPM motor the d-axis current operates enough to weaken the magnetic field, so the rotation speed increases but the torque decreases. However, the rotor geometry in an IPM motor is created so that there is a difference in inductance between the d-axis and q-axis, so it is possible to generate torque with the d-axis current, which weakens the magnets. This makes it possible to recover the part weakened by the flux. Consequently, an IPM motor achieves a greater range of operation by incorporating field weakening controls.
For this reason an IPM motor's characteristics depend greatly on its rotor geometry, so studies using the magnetic circuit method are difficult. In order to perform an advance design study accurately, an electromagnetic field analysis using the finite element method is necessary.
This Application Note presents the use of magnetic field analysis to obtain the efficiency of an IPM motor in each current phase with a rotation speed of 1800 rpm and the current amplitude of 4.0 A when the motor is driven by sinusoidal wave current.
31 - Iron Loss Analysis of an SPM Motor Including the Effect of Press-fitting Stress31 - Iron Loss Analysis of an SPM Motor Including the Effect of Press-fitting Stress
Module:DP,DS,LS2013-10-28
The laminated structure of a core in a SPM motor can be sustained using press-fitting or shrink fitting. The press-fitting stress needs to be accounted for in the iron loss evaluation because the stress caused by press-fitting is known to increase the iron losses when a magnetic steel sheet is used for the core of the motor.
An iron loss is generated by the magnetization field in displacement with a steel sheet. The size of the iron loss is dependent on the iron loss properties of a steel sheet. The iron loss characteristics of a steel sheet deteriorates by stress from press fit coupling. The stress generated by the press fit coupling is distributed in areas in which the section in the back yoke becomes large. In order to evaluate the iron loss with good accuracy, it is necessary to obtain the stress distribution for the magnetic flux, time variation, and steel sheet with accuracy.
This note presents the use of the press fit condition to model a core and frame and obtains iron loss density for when the generated stress is used and not used.
29 - Iron Loss Analysis of an SPM Motor with Overhanging Magnet29 - Iron Loss Analysis of an SPM Motor with Overhanging Magnet
Module:LS,TR2013-01-28
There are times when permanent magnet motors are designed with a magnet made with overhang, in other words made longer than the stator's stack length, in order to strengthen the magnetic field that it creates. A space is necessary in the stator core to supply the coil ends, and there is a wasted space in the rotor if the rotor and stator have the same stack length, so a magnet is placed in this space with the objective of increasing the magnetic flux without making the magnet thicker. However, the magnetic field produced by the overhanging part of the magnet enters the stator at an angle, so magnetic flux is produced in the lamination direction, which creates a possibility of increasing eddy current loss by a wide margin. When the overhang is too big, the magnet's magnetic field goes to waste because it does not reach the stator.
For this reason it is necessary to set up the overhang amount properly while looking at the trade-off between an increase in torque and an increase in losses. A magnetic field analysis using the finite element method (FEM), which can obtain the relationship between a three dimensional magnetic field and eddy currents, is an effective method for an advance study.
This Application Note presents the use of a no-load iron loss analysis of an SPM motor with and without an overhanging magnet.
21 - Iron Loss Analysis of an SPM Motor Including the Effect of Shrink Fitting21 - Iron Loss Analysis of an SPM Motor Including the Effect of Shrink Fitting
Module:DP,DS,LS2013-10-28
A magnetic steel sheet is used for the iron core in a motor. A frame is shrunk into a stator core in order to sustain the laminated structure and to improve the strong joint between the frames. It is know that a compressive stress is generated during the shrinking process which increases the iron loss process. Therefore, it is important to account the affects of stress during iron loss evaluation. Therefore, it is important to account the affects of stress during iron loss evaluation.
An iron loss is generated by the magnetization field in displacement with a steel sheet. The size of the iron loss is dependent on the iron loss properties of a steel sheet. Iron loss characteristics of a steel sheet deteriorates when there is stress in shrinkage. The stress generated by the shrinkage is distributed in areas in which the section in the back yoke becomes large. In order to evaluate the iron loss with good accuracy, it is necessary to obtain the stress distribution for the magnetic flux, time variation, and steel sheet with accuracy.
This note presents an analysis to obtain the iron loss density of an SPM motor both including and not including the stress caused by shrink fitting.

Top of Page


Contact US