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Flyback power supply in Circuit Maker

_lazor_ 5163 27
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  • Flyback power supply in Circuit Maker

    1. Introduction
    Flyback converter is a buck-boost converter. It is one of the most popular topologies used to power devices with low power, has gained popularity thanks to its simple design and simple principle of operation. Many companies have added their solutions, improving some parameters; dynamic losses on the key were reduced, interference emission was removed from the optocoupler).

    The principle of operation is very well illustrated by Wikipedia, so I will quote it:


    Flyback power supply in Circuit Maker
    Fig. 1 Diagram of the flyback converter


    Flyback power supply in Circuit Maker
    Fig. 2 Two operating states of the converter


    The schematic of the converter is shown in Fig. 1. It operates on the principle similar to the buck-boost converter with a separated choke creating a transformer. When a continuous stream of magnetic induction in the reactor is maintained (continuous operation), two operating states can be distinguished:
    - When the key is short (figure 2 at the top), the primary winding is connected to the voltage source. The current flowing through the primary winding and the magnetic flux in the core increases and the energy is stored in the transformer. The voltage on the secondary winding polarizes the diode. The output load is fed from the output capacitor.
    - When the key is open (figure 2 at the bottom), the magnetic flux in the core decreases. The voltage on the secondary winding polarizes the diode in the direction of conduction and the current of the secondary winding flows through this diode into the load and the capacitor.
    https://pl.wikipedia.org/wiki/Przekszta%C5%82tnik_flyback

    The schematic diagram is a simplified version that allows a better understanding of the principle of operation. The actual system is struggling with many problems that would not occur in an ideal arrangement, among others dynamic losses on the key, overvoltages on the primary winding, need for feedback or power supply for the controller. The following material is to bring closer the requirements regarding the power electronics equipment and problems related to PCB design. The material was created with the help of the user -RoMaN-, and the used controller is TNY280.

    2. Tools and power electronics
    Power electronics is a specialization that requires specific knowledge and equipment in relation to general electronics. You have to keep in mind that working with mains voltage is ALWAYS dangerous. Knowledge about protection against electric shock and awareness of what an error may end is mandatory.
    In brief, I will describe what tools and equipment I used in this project.

    Circuit Maker

    As PCB design software, I chose Circuit Maker. This is a stripped down version of the Altium Designer program (Protel) available for free. It is a convenient tool for me with still great possibilities, a large database of projects and a connection to the base of Octopart elements. The latter is extremely useful, because if someone has already used the element we need, we will have a ready model, footprint and sometimes a 3D model, if we use the element as the first in the Circuit Maker community, we can create it by adding a brick. Many elements are made very well (which I consider to be a lot of plus Circuit Maker), however, a few have happened to me badly.

    The project can be found under the link:
    https://workspace.circuitmaker.com/Projects/Details/Kamil-Gulczuk/TNY280-flyback-12V-1A

    Equipment for power electronics

    Flyback power supply in Circuit Maker
    Figure 3. Equipment and station used to run and measure the power supply.

    Separator transformer
    This is one of the most important elements ensuring protection against damage to measuring equipment and, above all, our health. ALWAYS we supply the tested system with a separating transformer! We DO NOT CONNECT the oscilloscope to it! Why? Because we get rid of earthing from the oscilloscope housing which is unacceptable, because dangerous voltage will appear on the housing of the measuring device!
    For advice on tinkering with the PE wire in the measuring device, I will give a warning!

    Autotransformer
    Sometimes it's worth to run the system from a lower voltage, for smaller sound-light effects, although it is not required
    Reminder - the autotransformer does not provide galvanic isolation.

    Such attention to the transformer and autotransformer.

    The initial magnetizing current of the separating transformer and the autotransformer can be so large that it can release the overcurrent protection, which does not mean that the equipment is damaged. In order to avoid triggering the protection, I recommend using NTC thermistor in series.

    Probes for oscilloscope
    At high potential, we use x100 probes with 2kV DC isolation. Overvoltages in this type of systems can reach up to 1kV, and ordinary x10 probes can not withstand them and damage them.

    Oscilloscope
    Currently, the 100 MHz band is standard, but the usual 25 MHz is still sufficient for power electronics, because we operate on the first harmonic frequency up to 300 KHz rectangular waveform and multiplicity of the first harmonic. Of course, the better the frequency bandwidth, the more accurate oscillograms, but it is not that important.
    Remeber! Oscilloscope channels are not usually isolated (in cheap oscilloscopes certainly are not) from each other, so we connect the oscilloscope ground probes to one point to avoid a short circuit.

    Workplace
    Personally, I have eternal mess on the desk, but the place where I run the system is to be ordered, clean and with insulated substrate (I use a polypropylene plate).Why? Damage to the system due to a lost resistor or tin ball lost somewhere under the circuit is as effective as it is frustrating.

    3. Elements of the scheme

    Why TNY280? It is an easy-to-design construction that gives a satisfactory final result.

    Flyback power supply in Circuit Maker
    Figure 4. diagram

    Looking at the schema at first glance, we see that it is much more complex than the overview scheme from Wikipedia. I will try to describe the individual functional elements in this diagram.

    Snubber
    The fundamental principle of operation of this topology is the accumulation of energy in a reactor with two (or more) windings, conjugated magnetic field. Unfortunately, not all of the stream is coupled with secondary windings, so during the process of key transition into the high impedance state, the energy accumulated in the inductance of dissipation looks for an outlet in the form of a current source, thus creating large voltage surges. To limit voltage surges, we use snubber. In the case of this project, I use the RCD snubber (RCD from the Diode Capacitor Resistor), which reduces the amplitude of the overvoltage and allows the energy to be lost from the dispersed inductance.

    Flyback power supply in Circuit Maker
    Figure 5. Snubber

    Flyback power supply in Circuit Maker
    Figure 6. The course on the drain relative to GND. In the red frame, the vibration on the gauge.

    feedback
    The feedback in the case of TNY280 is implemented in the simplest way; when the voltage reaches the set value (Zener diode + Vf optocoupler diode) the EN / UV pin is shorted to GND and the controller switches off. It is a very simple solution in relation to eg changing the control signal fill, at the same time very effective at very low power and a good filter on the secondary side. Such a solution introduces much higher ripple voltage at the output, but simplifies the feedback to such an extent that we do not have to worry about whether our system will diverge (the system is always stable).

    Flyback power supply in Circuit Maker
    Figure 7. Feedback

    Bias winding
    In many controllers, the bias winding is responsible, among others, for the power supply of the controller, but in the case of TNY280 the system is supplied directly from the drain tubing, and the bias winding is optional. The use of bias winding in the case of TNY280 ensures reduced energy consumption at low load and the ability to configure overvoltage protection.

    Flyback power supply in Circuit Maker
    Figure 8. Bias winding

    Transformer
    When powering the device with mains voltage, special care must be taken and the transformer itself must meet the safety standards. If we do not have the knowledge and experience in winding transformers, I do not recommend doing it myself. The transformer used in the article was acquired at Feryster with the designation TI-EF20-12V-1A-W.

    4. Measurements
    Measurement of ripple at the output
    Measurement of ripple and feedback are carried out directly on the output capacitor. In order to minimize the effect of signal attenuation through the loops of the oscilloscope probe itself, we use a silver-plated wire wound on the probe:

    Flyback power supply in Circuit Maker
    Figure 9. Probe with silver-plated wire.

    Signals not measured in this way may look better (less ripple) due to the introduction of damping.

    Flyback power supply in Circuit Maker
    Figure 10. Ripples at the exit

    Performance

    Fitness is the parameter that we want to know next when we make sure that our system is working properly. Many beginners do not have wattmeters, thanks to which we can easily and in a simple way measure the power consumed by the power supply from the network.

    Based on the material:
    https://www.power.com/sites/default/files/PIU-102_MeasuringEfficiency.pdf

    I will make three measurements with two equal meters

    1. Measurement with the I-prober 520 current probe and the SDS1022DL oscilloscope
    2 and 3 UT33C Multimeter

    Flyback power supply in Circuit Maker
    Figure 11. Measuring points.

    For each of the measurements I use the same load - a 20 Ohm resistor. Current on load:

    Flyback power supply in Circuit Maker
    Figure 12. Current on load.

    Distributed power on the resistor: 0.632 A * 12.11 = 7.654 W

    Measurement first

    The current probe is a very useful tool to visualize the current waveform in the system.

    The measurements were made at two different alternating voltages: 230 V and 142 V

    Results for 230 V

    Flyback power supply in Circuit Maker
    Figure 13. Current waveforms after the rectifier bridge for 230V

    Flyback power supply in Circuit Maker
    Figure 14. A single current pulse after the rectifying bridge for 230 V

    Results for 142 V

    Flyback power supply in Circuit Maker
    Figure 15. Current waveforms after the rectifier bridge for 142 V

    Flyback power supply in Circuit Maker
    Figure 16. Single current pulse after rectifier bridge for 142V

    I do not want to write down the calculations here, so I will give final results:

    For 230 V - 97.6%
    For 142 V - 86.2%

    Measurement of the second

    Made at the same point as the previous one, but with the UT33C multimeter. From the fact that in the picture of the alphanumeric display nothing is interesting, I will give only results:

    For 230 V - 84.2%
    For 142 V - 87.4%

    Measurement of the third

    -RoMaN- he instructed me to carry out the measurement in one more place, where the results will be more reliable. At this point, I also measured the UT33C multimeter.

    For 230 V - 86.1%
    For 142 V - 87.6%

    Due to the poor quality of the oscilloscope and its resolution in the calculation of the average signal (4 mA) these results are completely irrelevant and have to be rejected, but the waveforms show very well that the peak current at a load of 7.65 W is for 230 V up to 284 mA ! I hope that this will help illustrate why PFC (power factor correction) systems are so important in pulse power supplies.

    The remaining measurements look more credible, the only curiosity is the fact that the efficiency is better at the lower voltage supply. This is due to the fact that the increase in losses associated with conduction (diodes, copper resistance, leakage current of capacitors, etc.) is smaller than the increase in losses associated with the increase of supply voltage (dynamic losses on the key).

    5. PCB
    Flyback power supply in Circuit Maker

    Implementation of the diagram is a very important stage in the design of the device, but the challenge is also the correct distribution of elements on the surface of the PCB. The scheme is considered as a set of ideal elements, where GND has the same potential everywhere. Unfortunately, the common error that I observe is the same GND treatment on the physical tile.
    I will mention a few tips related to the physical placement of elements on the PCB.

    1. Capacitors close to decoupling
    Referring to the article about EMI interference:
    https://www.elektroda.pl/rtvforum/viewtopic.php?t=3563554&highlight=

    When assembling elements on a PCB, we should keep current loops in mind. In the case of flyback we have two states: an open key and a closed key. In the first case, the current flows through the primary winding, the key and higher harmonics through the first capacitor:

    Flyback power supply in Circuit Maker
    Figure 17. Current loop for the open key


    In the second case, when the key ceases to conduct, the energy stored in the inductance of the transformer's dissipation is considered as a current source whose energy we need to dissipate on the gauge.
    The red path shows the current flow in conditions when the energy is accumulated in the C3 capacitor, the yellow one shows the current loop flow through the transil if the surge amplitude is higher than the transil voltage (when the C3 capacitor accumulates too much energy).

    Flyback power supply in Circuit Maker
    Figure 18. Current loop for a closed key


    The purpose of a correct PCB design is to minimize the surface area of these loops. This can be accomplished even better by a double-layered PCB design or placing elements vertically.

    2. Risk of puncture

    When working with high voltage, we must remember that the distance between tracks - where there is a large potential difference - can easily be broken (creeping currents). The distance impact in which the breakdown occurs depends on the voltage, pressure, pollution, ambient temperature or shape of the electrodes. It's much easier to make a puncture in the blade-to-blade configuration, so we avoid guiding angular paths to minimize the chance of puncturing.
    Depending on the working conditions and materials used, the gap between the tracks should be within 4mm to 12.6mm.

    Flyback power supply in Circuit Maker
    Figure 19. Intentionally unoriented path

    Although in Fig.19 it would be wise to route paths perfectly between two neighboring ones, the shift is deliberately introduced.

    3. Heat dissipation from elements (element dissipation power and heat sink)

    A common mistake in beginners is a misunderstanding of the power dissipation parameter on the element. This parameter is given for very good (in practically unachievable conditions) heat dissipation by the heat sink. In the case of TNY280, we have two PCB surfaces that act as a heat sink (thermal pad) (232 mm ^ 2 and 645 mm ^ 2) for which thermal resistances are given (analogously 70 degrees / W and 60 degrees / W). In my case, it is a little over 300 mm ^ 2 and I do not overload the system over what the manufacturer gave me. Additionally, it is worth remembering that the barrier diode on the secondary side also has quite a lot of power, so it is worth to have a larger thermal pad.
    It must be remembered that such thermal pads make it difficult to solder elements, because the power starts to dissipate on the heat sink, which makes it much harder to warm up the soldering point.

    Flyback power supply in Circuit Maker
    Figure 20. Photo from a thermal imaging camera. All PCBs

    Flyback power supply in Circuit Maker
    Figure 21. A picture from a thermal imaging camera. The diode on the secondary side.

    6. Notes
    I did the project completely for sport (experience is the basis), but I will share what mistakes I made:
    - for small pads around THT elements, so that when I cut the wires a few pads fell off
    - I forgot about test points, so I had to solder additional wires? for the derivation of elements
    - one of the elements was badly designed and had a contour on the outline layer, which is milled by the machine - instead of a capacitor I would have a hole in the PCB, but during the verification of gerberas it was possible to notice and change it
    - a few mistakes with element size and spacing (C3, C8 and C4)

    These types of errors happen, so you can hardly assume that the first revision of the PCB will meet our expectations, so you have to assume at least 2-3 version of the PCB to get rid of all the failures.

    7. Applications
    Although the project can fail many people, because there is no calculation hererelated to individual elements (snubber, transformer, filters), but the purpose of this article was to show that, apart from these calculations, there are also many equally important steps at which many people make mistakes. To properly design the device, all steps must be performed correctly, if we make a mistake somewhere, the device will not work properly. It is worth limiting the number of places where we can potentially make mistakes by using the software provided by the manufacturer of the driver or commissioning items requiring precision to companies that have experience in this field. The smaller the field for error, the sooner you can diagnose the place where the mistake was made, so it costs us less time and nerves.

    Flyback power supply in Circuit Maker

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    About Author
    _lazor_
    Moderator Design
    Offline 
    _lazor_ wrote 1781 posts with rating 333, helped 160 times. Live in city Wroc³aw. Been with us since 2016 year.
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  • #2
    And!
    Admin group Design
    Interesting material, designed from the theory and scheme in Circuit Maker, through the board and its visualization, to assembly, commissioning and testing.

    The material can help start with the topic of interested people, it would be interesting to develop measurements with better equipment, there may be companies interested in presenting their equipment and expanding the content of this material?
    The basic measurements showed some important conclusions, eg the issue of PFC.
  • #3
    Macosmail
    Level 33  
    I have only one small attention. Is it not worth replacing D3 diodes with a "fast" one, eg UF4007? I think that it would positively affect the efficiency.
  • #4
    And!
    Admin group Design
    The project shows that online Circuit Maker is a useful tool, maybe a tutorial on elektroda.pl would come in handy?
  • #5
    _lazor_
    Moderator Design
    Macosmail wrote:
    I have only one minor attention. Is it not worth replacing D3 diodes with a "fast" one, eg UF4007? I think that it would positively affect the efficiency.


    Generally, it is a diode in the circuit of a snubber, so the energy that gets there anyway has to turn into heat. The value of trr in this case is not so important, because the discharge of the load from the diode is slowed down by the resistors in the series. If someone has UF4007 on hand (and it's popular) then you can use it calmly.

    When it comes to improving efficiency, you can change the diode D7 to SiC.


    And! wrote:
    The project shows that online Circuit Maker is a useful tool, maybe a tutorial on elektroda.pl would come in handy?


    This is a very good idea, there are many very good English-language guides on which to follow.
  • #6
    Janusz_kk
    Level 23  
    And! wrote:
    The project shows that online Circuit Maker is a useful tool

    Does he open old projects from protela 98?
    And for the article plus, lack of a bit of theory is a bit at odds with the desire to show how it's done.

    Added after 16 [minutes]:

    _lazor_ wrote:
    Generally it is a diode in the circuit of a snubber, so the energy going there is going to change into heat anyway. The value of trr in this case is not so significant

    Well, I will not agree, this diode is supposed to "catch" the peak and that it is free, it does not do it, it can be seen on the oscillogram that this peak is about 80V,
    In bad conditions, when the network is out of the network, the 80V may fail the key and it will fail. For the same reason, giving a resistor
    R3 100om is a mistake, it makes a completely unnecessary voltage jump. The professional power supplies do not have this and the diode is fast. The C3 condenser is a bit small but it may be enough for low power, it is safer to slightly oversize it.
    As for the start of the inverter, TNY type circuits do not like too much load at a particularly resistant start, as the inverter does not start it goes with smoke, the cause is the current source powering it at startup, too long start time overheats it and it has no protection it does a short-circuit short-circuit.
  • #7
    _lazor_
    Moderator Design
    Janusz_kk wrote:
    And! wrote:
    The project shows that online Circuit Maker is a useful tool

    Does he open old projects from protela 98?
    And for the article plus, lack of a bit of theory is a bit at odds with the desire to show how it's done.


    Unfortunately, I do not know if it is possible. I found such a note on this topic:
    https://circuitmaker.com/forum/posts/211895

    There will be time for articles focusing on theory
    ;)
    Here I wanted to present the more physical aspects of design about which it is relatively difficult to find information on the web.

    Janusz_kk wrote:
    _lazor_ wrote:
    Generally it is a diode in the circuit of the snubber, so the energy going there is going to change into heat anyway. The value of trr in this case does not have such significance

    Well, I will not agree, this diode is supposed to "catch" the peak and that it is free, it does not do it, it can be seen on the oscillogram that this peak is about 80V,
    In bad conditions, when the network is out of the network, the 80V may fail the key and it will fail. For the same reason, giving a resistor
    R3 100om is a mistake, it makes a completely unnecessary voltage jump. The professional power supplies do not have this and the diode is fast. The C3 condenser is a bit small but it may be enough for low power, it is safer to slightly oversize it.
    As for the start of the inverter, TNY type circuits do not like too much load at a particularly resistant start, as the inverter does not start it goes with smoke, the cause is the current source powering it at startup, too long start time overheats it and it has no protection it does a short-circuit short-circuit.


    All waveforms are consistent with the documentation from PI:
    https://www.power.com/sites/default/files/product-docs/tny274-280.pdf

    Drawings from 6 to 9.
    In addition, it is also a project from the documentation, so I doubt it would contain errors when it comes to construction.

    Of course, I miss this project, but there should be a varistor that will protect the system against overvoltages.

    If you want I can throw UF4007 because I have at hand, but I doubt that this will improve the overvoltage on the key drain.

    The 100 Ohm resistor is fine. Without it we would have an LC || R circuit instead of RLC || R. Thanks to the slight increase in tension on the drainage, we do not torture that much as R2. Remember that the drain limit is 650V, to which there is still a good safety margin, even if a 20% overvoltage
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  • #8
    TechEkspert
    Editor
    Last month we had the opportunity to talk about sub- DC / DC converters: [url=https://www.elektroda.pl/rtvforum/topic3561772.html] SMPS
    this project is a smooth transition from theory and design to practice and measurement.

    The effects of exchanging D3 diode for fast, and D7 for SiC are best verified experimentally by measurements,
    but what measuring equipment would be needed to detect differences?

    At present, SiC are available only from the largest distributors.
  • #9
    _lazor_
    Moderator Design
    I will try to answer any questions and comments as much as possible, I would like answers to be supported by measurements and materials from companies that may be considered trustworthy by their experience, but it takes some time.

    So I prepared a more substantive answer to the question about the diode D3.

    I made measurements again on the driver's drain. The supply voltage is 230V (325V after the rectifier) First for the 1N4007GP diode:
    Flyback power supply in Circuit Maker
    Flyback power supply in Circuit Maker

    As I did not have UF4007 on hand, I used UF5408, which is similar to UF4007. Here are the results:

    Flyback power supply in Circuit Maker
    Flyback power supply in Circuit Maker

    I also found material from TI on the selection of diodes for the snubber circuit:
    http://www.ti.com/lit/an/snva744/snva744.pdf

    Quotation:
    "However using standard recovery diodes of performance for efficiency and EMI performance."

    In the above material you can read about the many advantages of using the recovery diode standard in RCD and R2CD circuits, but also about faults in other types of snubber circuits. The use of the R3 resistor also aims to suppress vibrations, thus reducing the generation of interference.
    This is well illustrated by the fact that electronics are not black and white, and the selection of components depends on the context of the whole device. It is not a simple task, and profit or loss can be very minimal.

    @TechEkspert

    If the change in efficiency would be significant (1% -1.5%) then it can be detected on the same equipment as I was currently doing measurements on. The results are certainly not adequate to reality, but the change in efficiency can be detected, although it will be difficult to say exactly how much.


    I encourage you to ask questions, I will try to answer all questions as accurately as possible.
  • #10
    TechEkspert
    Editor
    With this power supply power, the detection of 1% -1.5% changes is more of an educational than a practical one? so your measurement tools seem OK.

    The question what specific tools would be needed to extend the scope of measurements / analysis, maybe companies with such resources would be interested in providing such equipment to you during measurements in exchange for information about the equipment used on elektroda.pl?

    In the future, you could also perform a review of the shared equipment.
  • #11
    _lazor_
    Moderator Design
    The lower the power of the power supply, the more difficult it is to achieve greater efficiency. The world goes in the direction that the devices operate with increasing efficiency and 1% -1.5% gain only by changing one component is something very practical, because it looks very good in pillars
    ;)
    and that SiC cheaper it can become a concrete replacement.

    To get a more precise result one would have to use a calibrated watt meter that will be able to correctly measure the TrueRMS current with such a large number of harmonics in the signal.

    As for the sharing of equipment by companies, it is really hard for me to express myself.
  • #12
    Thorgus
    Level 12  
    What kind of probe are you testing high voltage?
  • #13
    _lazor_
    Moderator Design
    Thorgus wrote:
    What probe are you testing high voltage?


    I use Hantek T3100
  • #14
    Macosmail
    Level 33  
    I will also pay attention to the C9 capacitor. The scheme has no annotations, and the layout looks like a regular foil. At this point, it should be a special type Y capacitor usually specified at 250-275V AC RMS, but according to standards withstanding min. 8kV overvoltages.
    Flyback power supply in Circuit Maker Flyback power supply in Circuit Maker
    Flyback power supply in Circuit Maker
    Additionally, the output diode can be exchanged for Schottky with the appropriate voltage.
  • #15
    Janusz_kk
    Level 23  
    _lazor_ wrote:
    The use of the R3 resistor is also intended to suppress vibrations, thereby reducing the generation of interference.

    I still think that it is too big in this place, that's why the diode change did not show much, and as far as katting is concerned, R3 is more catabolic with current pulses than R2, on which constant power is emitted.

    Added after 1 [minutes]:

    The loss of the inverter can be reduced as described by Macosmail, or by giving a mosfet and an additional control winding instead of a diode.
  • #16
    _lazor_
    Moderator Design
    @Macosmail I agree with you, KEMET PHE850EA4220MA01R17 was used here (BOM can be found on the Circuit maker website https://circuitmaker.com/Projects/Details/Kamil-Gulczuk/TNY280-flyback-12V-1A)
    Y2 has been used because there is no need for reinforced insulation (Y1) for a device that works in CAT II
    https://www.hioki.com/en/support/quality/Safely/

    Janusz_kk wrote:
    The loss of the inverter can be reduced as described by Macosmail, or by giving a mosfet and an additional control winding instead of a diode.


    The driver has an integrated mosfet key, so adding an additional key would require the driver to be replaced. I do not fully understand what is going on with the additional control winding, because as the note says, BIAS winding has been used to reduce losses and provide overvoltage protection.
  • #17
    Banan-PL
    Level 11  
    I confirm that, contrary to what it seems, diode D3 should be free . Particularly, the difference can be seen in EMI research.
  • #18
    Janusz_kk
    Level 23  
    _lazor_ wrote:
    so adding an additional key would require the driver to be replaced. I do not fully understand what is going on with the additional control winding,

    It's a controlled rectifier on the output, i.e. a mosfet instead of D7, and he needs to control the additional winding, but fighting for one or a few percent of efficiency is meaningless to me for the small power of the power supply, something like thick kilowatts of energy.

    Added after 1 [minutes]:

    Banan-PL wrote:
    I confirm that, contrary to what it seems, the D3 diode should be free. Particularly, the difference can be seen in EMI research.

    For emi, he designs the board accordingly and does not choose a diode.
  • #19
    _lazor_
    Moderator Design
    Janusz_kk wrote:
    Banan-PL wrote:
    I confirm that, contrary to what it seems, the D3 diode should be free. Particularly, the difference can be seen in EMI research.

    For emi, he designs the board accordingly and does not choose a diode.


    Components are also important in generating EMI interference. The material that I sent from Texas Instrument also confirms that choosing a fast diode would result in increased noise emission (in the case of RCD and R2CD, where in the above flyback design there is a R2CD snubber variation).
  • #20
    And!
    Admin group Design
    On the example of the project, you have raised many threads, efficiency and dependence of efficiency on the components used, safety and types of components used (capacitors) and good practices in the reduction of EMI.
    Experimental checking of the impact of the elements used on the generated EMI as well as the efficiency of energy conversion would be a great continuation of the project.
  • #21
    _lazor_
    Moderator Design
    With the EMI disturbance chamber, there may be quite a problem, but there is a good chance that after the holidays the power supply will be examined with more specialized equipment in terms of efficiency. It will be an extremely interesting experience to compare measurements with a multimeter and a specialized power meter.
  • #22
    And!
    Admin group Design
    Should the PFC active system be used for the PF compensation, or would the constant inductance in the power supply circuit allow the PF to be improved for a constant power received from the power supply?

    As for the EMC, a cheaper version without a chamber could be suitable probes and analyzer:
    https://www.elektroda.pl/rtvforum/topic3267173.html
  • #23
    _lazor_
    Moderator Design
    With this power, the current filter must be enough, using an active filter would drastically reduce the efficiency of the device.

    The issue of electromagnetic interference is very interesting and at the same time very poorly understood, and many errors are often made in this matter. Such a basic division is a near and distant field.
    The device that you link is used to study the near reactive field (because the near field is still divided into the Fresnel region), that is, separate components of the electric and magnetic field, which can physically affect the device's load (sources of interference). Such interference, of course, can harm other devices in the area and can not be underestimated.
    I-prober 520 is able to test the magnetic component, but only in the range up to 5Mhz.
    It can be said that the transformers operate on the principle of a near polo
    ;)


    In the chambers, however, a distant field is also being investigated, i.e. those that we associate with antennas more and this field can interfere with their work.

    It is described in more detail in wikipedia:
    https://en.wikipedia.org/wiki/Near_and_far_field#Far-field_diffraction
  • #24
    Tuning Marek
    Level 20  
    Hello, well presented topic when you want to learn but I have a request because I have a problem with English or the author could with English names where it uses names in brackets to translate into Polish name or how it understands in your own thanks and please do not punish me in a word no longer this year.
  • #25
    _lazor_
    Moderator Design
    Tuning Marek wrote:
    Hello, well presented topic when you want to learn but I have a request because I have a problem with English or the author could with English names where it uses names in brackets to translate into Polish name or how he understands in his own thanks and please not punish me in words already not this year.


    I will try to do it today. However, I regret to say that our native naming is already an exotic and it is hard to find something specific on the web by searching for Polish names. However, in old and still good Polish books these names appear, so it's worth knowing them.
  • #26
    TechEkspert
    Editor
    It's been long since there was material from @NDN Warszawa
    :)
    maybe in an interesting way you will supplement the topic based on your measurement experience and your equipment and the parameters of the equipment being in the distribution of manufacturers?
  • #27
    _lazor_
    Moderator Design
    Thanks to the courtesy of Etteplan Poland, the YOKOGAWA WT310E power meter has been made available
    Flyback power supply in Circuit Maker

    Measurements:
    Flyback power supply in Circuit Maker

    The efficiency with respect to the supply voltage was measured under the power conditions of 7.4 W

    The efficiency in relation to the load was measured at the 230V AC power supply.

    Thanks to this measurement we can say with certainty that the technical measurement with the use of multimeters for PLN 50 is not accurate and you have to watch out for revelations when someone gets very good fitness and does not want to give the name of the meter on which he made measurements.
    At the same time, efficiency 82% for the simplest flyback at about 60% of its maximum power, I consider a really good result.
  • #28
    And!
    Admin group Design
    A very good supplement to the material is a great thing when you have contact with a company that is willing to provide expensive measuring equipment.
    An experimental approach to the topic is always worth.