Ferrite Core Transformer Design Software Free Download
Bernd Manison
Why my ferrite transformer drawing 15amp peak at 40-volt RMS at NO loads ?, I mean when the secondary is not generating any ARC or the secondary wires are not even close? I have measured the secondary wire resistance. The resistance is 535 ohms.
Calculating ferrite transformer is a process in which engineers evaluate the various winding specifications, and core dimension of the transformer, using ferrite as the core material. This helps them to create a perfectly optimized transformer for a given application.
The post presents a detailed explanation regarding how to calculate and design customized ferrite core transformers. The content is easy to understand, and can be very handy for engineers engaged in the field of power electronics, and manufacturing SMPS inverters.
You might have often wondered the reason behind using ferrite cores in all modern switch mode power supplies or SMPS converters. Right, it is to achieve higher efficiency and compactness compared to iron core power supplies, but it would be interesting to know how ferrite cores allow us to achieve this high degree of efficiency and compactness?
The figure 96.3 is the number of secondary turns that we need for the proposed ferrite inverter transformer that we are designing. As stated earlier since fractional vales are difficult to implement practically, we round it off to 96 turns.
Hi again Swagatam. You referred me to the article below which is very informative, so many thanks for that, but I am still a little confused on how to proceed in my choice of core size and wire size for a 1KW ferrite tranformer.
As you also state that it is important to correctly balance the core size with the delivered power to ensure neither saturation or under utilisation of the ferrite core there would obviously be a great deal of practical use for a design calculator where we could enter the parameter of input voltage, output voltage, frequency and power required and then the calculator delivers the optimum core size, numbers of turns for the primary and secondary windings and wire csa of both. Does any core manufacturer actualy provide anything like that to your knowledge to reduce the need for an experimental approach?
I used the tutorial to determine that for 240v RMS (not 220V as in the example) I would need a transformer secondary delivering 340V (peak) + 20v (headroom) = 360v. I have also determined that from a 10.29V (low 12v battery again from your tutorial) source I would require a 35:1 step up ratio, hence if using 3 turns on primary I would need 105 turns on the secondary. The ETD49 ( the largest) core in the datasheets you sent suggests a maximum of 692watts, so is a 1KW transformer something that is difficult to construct?
I see below that others are suggesting multiple parallel tranformers.
Can you also put me on the right path of where to start for determining the csa of the wire I require?
I guess the reactance of the 3 turns is a measure that would be useful and then I could probably calculate the current at a given frequency using the inductive reactance formulae 2piFL. Is that right?
Thank you for a very helpful Ferrite transformer guide.
I was able to create a worksheet to verify your results as well as insert values for a toroid core from Magnetics Inc. which confirmed the values I have been using to create a higher power inverter at higher frequencies using home made litz wire with 0.25mm diameter awg30 enameled wire.
The Power Chart characterizes the power handling capacity of each ferrite core based upon the frequency of operation, the circuit topology, the flux level selected, and the amount of power required by the circuit. If these four specifics are known, the core can be selected from the Typical Power Handling Chart.
The power handling capacity of a transformer core can also be determined by its WaAc product, where Wa is the available core window area, and Ac is the effective core cross-sectional area. Using the equation shown below, calculate the WaAc product and then use the Area Product Distribution (WaAc) Chart to select the appropriate core.
A ferrite transformer has a magnetic core in which coil (inductor) windings are made on a ferrite core component. It offers low eddy current losses. It is normally used for high-frequency applications. Common ferrite core types are toroidal, closed-core, shell and cylindrical.
Depending on circuit designs, core types and applications of transformers, there are different topologies and names. These include shell type, pushpull, half-bridge and flyback. Irrespective of the topologies, some points to be kept in mind while designing ferrite transformers include frequency and temperature of operation, unit cost, size and shape. These should match the voltage levels of source and load, provide electrical isolation, prevent core saturation and minimise core losses.
The size and frequency of operation of a ferrite transformer depends on two broad applications: signal and power. A ferrite transformer used in signal applications is small and has higher frequencies (in the range of mega-Hertz). The one used in power applications is large and has lower frequencies (normally ranging from 1kHz to 200kHz).
Before designing a transformer, check your requirement and exact application. This may include input voltage, output voltage, current and frequency of operation. Then, consider other parameters like physical size, spacing, mounting style, isolation, leakage currents and temperature.
Acceptable temperature rise depends on the application and the designer. Two main causes of temperature rise in a transformer are core power losses and winding power losses. These can be calculated using standard formulae.
Thanks for the feedback! This kind of TV flyback transformers are meant for high voltage and high frequency applications. However, if you have spare ferrite cores and space is not an issue, you can use them but I think it would be a bit bulky.
Now, cores are of varied materials such as ferrites, steel, silicon, and many more. This article will focus solely on ferrite cores and expound on the different types, benefits, and applications. Additionally, we may give other knowledge that may be of importance to you.
Often, the magnetic ferrite cores have a combination of manganese, zinc, nickel compounds, and iron oxides. Since the compounds have low coercivity, they fall under soft ferrites. Ferrite core types comprise shell, toroidal, cylindrical, and closed-core.
Ferrite core transformers usually have a higher demand when compared to iron core transformers. The ferrite transformers have advantages, including resistance to elevated currents, low hysteresis losses, and no lamination required.
ETD cores; First, we have the ETD cores with minimum winding resistance at their center post. The winding resistance allows optimization of dimensions for increased power efficiencies. Furthermore, they suit inductors and power transformers efficiently.
E, I core; Its feature is a bobbin winding. And you can assemble it with ease. E, I core uses are; inverter transformers, broadband, power, converters, telecom inductors, and differentials.
Different applications and core types have varying names and topologies based on the circuit design. Some of the topologies include flyback, push-pull, half-bridge, and shell-type. Nonetheless, when designing any ferrite transformer with any topology form, consider the shape, unit cost, optimum temperature, size, and frequency. The mentioned points should uphold the transformer by minimizing core losses, providing electrical isolation, and preventing core saturation.
All in all, ferrite core transformers are the best option when considering high-frequency applications since they have efficient performance. The transformers have high magnetic permeability, high coercivity, and they conduct low electrical power. The high-frequency applications include switched-mode power supply, noise filters, RF (radio frequency) inductors, transformers, etc.
Iam designing 7kwt dc-dc converter that converts 750v DC into a 48V DC (140A) using LLC topology.working frequency is 45khz when at full load and up to 200khz when idle.and the problem is with transformer design.i have tried 6 different transformer constructions and all of them heat up very fast and severe.
My first transformer designs where so called integrated designs,where resonant inductor was incorporated in a transformer using leakage inductance between primary and secondary.that design showed rapid heat build up on the surface of the primary which was facing secondary (primary and secondary where separated in space,thus big leakage inductance present). then i have read about proximity effect and made a conclusion that i have to make separate external resonant inductor and transformer should have lowest value leakage inductance as possible,because if i got it right,leakage inductance makes eddy currents and thus heating nearest layers of the winding leaving all the rest layers cold.
That kind of design i have looked up in the infineon evaluation board of a 3 kwt llc converter appnote (www.infineon.com/.../Infineon-ApplicationNote_Evaluationboard_3kW_dual_phase_LLC-AN-v01_00-EN.pdf you can check it on the 25 page. infineon design has even more secondary turns with a foil (5+5), it also has air gaps on all three limbs of ferrite,it also has external resonant inductor. but somehow it work on a fantastic 100khz+ frequency,where all the skin effect and proximity effect are very limiting.
Power Design Ferrites are the right type of material for inductors and transformers as they offer twin advantages of low core pricing and low core losses. Generally, they are used in the frequency of 20 kHz To 3 MHz and in the saturating mode which requires low power and low-frequency operation. Power Design Ferrites are available in a variety of shapes and sizes, which makes them ideal for different applications.
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