Transformer's Book
We have already finished our book of transformers called "Transformers Book" is a product of 46 years of experience in the field and the achievement of many projects with a lot of different good results.Transformers book is not a theoretical work but a theoretic/practical work of Years of labor, despite it´s strong mathematical and physical background.
We know that a big part of this book is not found in any similar work, because We had been looking for those subjects by many years without any success. We gathered many papers of the IRE, IEE, IEEE and other societies of same importance in combination with our own work through many years to make possible its construction.
We could had written it in our own language but We tried to write it in English, with the intention to reach more people like possible, around the world.
The content:
The content is distributed in three volumes. The first one is currently availlable at Amazon.com with the ISBN 978-85-920396-0-8 at location:
https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=ISBN+978-85-920396-0-8
the second and third volumes are coming soon.
There are two versiom sthe paperback and the electronics book version (Kindle) that can be obtained quicly at any part of the world.
The content of the first volume:
Index:
Structure of the Matter and a brief view over atomic physics
Magnetism and Magnetic Materials
Ferromagnetic Domains and domain walls.
Initial Permeability, Rayleigh Constant and Rayleigh law.
Absolute and relative permeability.
Losses in Magnetics Materials.
Facts affecting the total losses
Loss behavior in different magnetic materials
Soft ferrites for high frequency applications:
Searching for a general loss model which could include harmonics and DC currents:
The MSE Approach - (Modified Steinmetz Equation)
The GSE Approach (General Steinmetz Equation)
Magnetic field produced by currents in endless sheets.
Addition of fields in two parallel plates.
Addition of fields in several layers:
Simulation by FEA (Finite Element Analysis)
Equivalent Circuit of a transformer:
Inductance formula definition (Toroidal Case):
Inductance Formula definition (Leakage inductance Case):
The equivalent circuit of a transformer and measurements of AC Resistance:
Skin Depth and Proximity Effect
Diffusion of magnetic field in a Conductor
Simple Rules in order to handle fields and currents in a single face.
Diffusion interrupted by change of field or current direction.
The proximity effect develops considerable losses.
Proximity Effect three-dimensional configurations.
Transformation from a round conductor winding to metal plate or sheet.
Dowell transformed circular wire windings into an "Equivalent Sheet" as follows.
Determination of Fr for the entire coil:
Dowell Relations – Simplifying the figure:
Expanding in series for simplification:
Skin and Proximity effects facing complex waveforms.
Behavior for complex waveforms.
We need to treat the problem through losses:
Determination of the Kr Curve.
Using Kr for loss calculation.
Further simplification with harmonics.
First Example: Calculation of a 4 Layers transformer with Copper sheet in the two coils.
Second example: Calculating ht losses:
Another method for the calculation of Fr.
Solution other than for paper and pencil:
Calculation in the design of a 20Kva inverter filter inductor.
Design of a ferrite 3Kva 200Khz power transformer for a ZVS-QRC telecommunication SMPS.
The Gap Losses - The approach.
The visual effect of the gaps.
Determination of losses by finite elements:
The calculation of losses in Litz Wires.
Calculating over a single Phase EI lamination transformer
Design of a sample E I transformer:
Determination of the better cost for a three phase transformer.
K Factor and K Factor transformers.
The problem of the loads and the current spectrum.
Different topologies of non linear loads and the K Factor:
A simplified but full precision, Matlab-Simulink K Factor Calculator.
The effect on the neutral current.
Classification of K factor according to loads and lines.
Sample project of a 50Kva three Phase distribution transformer for Kfactor = 13. 260
Winding Construction for Minimum Losses:
The content of the Second Volume:
Index of Vol II
A survey of different magnetic materials and cores
E I Cores for small Transformers
Pulverization and lamination needs for Eddy currents reduction and skin depth partial solution.
C Cores and C Composed cores for medium Power transformers
The problems of composition
Composed lamination for high power transformers
Cruciform cored transformers, optimization and the minimum degree
Simulations essays using FEA to see the behavior of the compositions
The importance of the definition of lamination standards
The Ferrite cores
The Powder Cores
MPP
High FluX
Kool Mu
X Flux
Vitroperm cores for High frequency transformers
Nanocrystaline cores for MagAmp
Metglass Magnetic Alloys
MicroMetals Powder Cores
The Exciting current of a transformer.
The magnetizing current (inductive part)
The real part
The problem of the inrush current
The effect of magnetic memory of the core
The problem of the initial value
The value of the saturation and the slope of the curve
The profile of the inrush current
The sympathetic inrush current
The magnetic pulse outside the transformer due to the inrush (Dangerous Consequences)
Transformers like a Voltage or Current power supply.
Transformer as a voltage source
The problem of the voltage regulation
The voltage accuracy as a potential measurement transformer
The transformer as a current source
The problem of the current regulation
The current accuracy as a current measurement transformer
The problem of Temperature
The external area approach (Average temperature)
The weight and loss approach (Average Temperature)
Calculation of temperature drop between layers
Temperature measurement of power transformers
Temperature measurement at light load and nominal voltage
Temperature measurement at nominal load and low voltage
The size and weight versus temperature time constant and the transient thermal impedance.
The complete thermal model of a transformer. Involving power losses, dissipation and thermal feedback. Using Simulink, Simscape and Thermal elements
The hot spots ant their measurement.
The forced cooling of transformers
Power Transformer optimization
The point of maximum efficiency
The curve of maximum point efficiency: maximum copper weight side or maximum core weight side.
Optimization constraints
By temperature
By Voltage Regulation
By special dimensions
By Cost
By efficiency
By impedance
The problem of skin and proximity effect in high power transformers
The orthogonality between proximity and skin effect
The exact calculation of proximity effect
The exact calculation of skin effect
Th simplified approach
Polyphase Transformers and High power polyphase Rectifiers
Three Phase Transformers
The rectification
The commutation principle
The commutation angle calculation for different configurations
Delta open and scott Transformers
Zig-Zag Topologies
Multiple Zig-Zag Topologies
Extended delta topologies
The transformers for high power industrial rectifiers and multiple topologies
The problem of multiple waveforms in the windings for polyphase topologies
The calculations of additional losses due to proximity skin effect in multiple windings at different waveforms.
The end Effect
Demonstration of the end effect by FEA (Finite Elements Analysis)
Causes
A thermographic photo showing the end effect
The difficulty to find a solution
A difficulty for partial solution
The strange effect
Who is the strange?
Strange effect Calculation
Definitions
Solutions
Planar Transformers and inductors
The planar approach
The windings problems and solutions
The printed circuit winding
Multiple printed circuit winding and flexible printed circuits
Interleaving coil and its effects over the H profile and the improvement of losses
Calculations of Additional losses due to skin proximity effect
Copper or aluminum Foil for high power solutions
The planar inductor, limitation by the fixed H profile
Planar solutions
REFERENCES. Of the Vol II
The Content of Volume three
Index of Volume III
Designing mains medium power Transformer (500KVA) using the (Cost Constraint algorithm).
The problems involved
Concluding; the usage of copper or aluminum.
Optimizing the height of the coil.
One simple mathematical, Matlab and Simulink Model for power transformers calculations
Designing a power choke of various tenths of KVAR using planar topology to solve gaps problems.
The geometric problem
Construction problems
Calculation of losses
Demonstrating the results by FEA
Designing a selective 500Khz power supply inductor with 2 different conductors.
Designing the inductor with Wire
Designing the inductor with foils
Calculating the inductor and concluding the impossibility to go ahead.
Installing a very thin conductor in parallel that solves the problem
Calculations to see the solution
Designing the same 500Khz power supply inductor with Printed circuit planar multilayer solution.
Transductors and magnetic Amplifiers (MagAmp)
The transductor – The revival from the grave - A forgotten theory
Mean voltage and flux changes
Addition of mean fluxes
Energy Storage in magnetic Cores
Summary of useful relationships
Basic operation of the transductors
Characteristic of a transductor
Control Ratio
Free magnetization transductor.
Forced magnetization transductor.
Supply Voltage
Power Output
Power amplification
Sel-Excited transductor
AC Magnetization Curve
Form Factor and waveforms of load current
Efficiency
Transient and steady-state operation of idealized transductors
Simplification of the magnetization curve
Voltage-time integral
Basic circuit equations
The self excitation
Mean fluxes and transductor Voltages
The self excited Transductors
Limitations of the simplified treatment
Action of the self excitation rectifier
Amplification of the self excited transductor in the steady state
The amperes turn ratio
The control characteristic
Transductors with auto excitation
Circuit operation of auto excited transductors
Singularity theorem for auto excited transductors.
Ampere turn ratio of auto excited transductors
Transductors with reactive Loads
Transient and frequency response of transductors
High speed transductors and magnetic amplifiers
Multi stage Magnetic Amplifiers
The new solutions for SMPS.
The regulation and control circuits
The simplicity of the regulation circuits
Appendix A
Appendix B
Appendix C
Appendix D
REFERENCES Of Vol III