      On some entry fields and on some calculation results that need comments, the tooltips are placed.
The content of these tips actually repeats the help points.

        1. On some input fields and on some calculation results that need comments, tooltips are placed.
The content of these tips actually repeats the help points.
        2. In the "Optimization" group, when changing the values using the arrows, the start of optimization begins automatically.But if the new value is entered "manually", then optimization should be started with this button.
        3. For the  PWM controllers, a frequency equal to half frequency of the master oscillator of the microcircui is set. The pulses of the master oscillator are fed to the outputs in turn, so the frequency at each output (and at the transformer) is 2 times lower than the frequency of the master oscillator.
        ICs IR2153 and similar ones of this ICs family are not the PWM controllers, and the frequency at their outputs is equal to the frequency of the master oscillator.
        Do not chase a high frequency. At a high frequency the switching losses in transistors and diodes increase. Also, at a high frequency, due to the small number of turns, the magnetization current is too high, which leads to a large idle current and, accordingly, low efficiency.
        4. The window fill factor describes how much of the core window the copper of all windings will occupy.
        5. The current density depends on the cooling conditions and on the dimensions of the core.
For free cooling, choose 4-6 A / mm2.
During ventilation, the current density can be selected more, up to 8 - 10 A / mm2.
Large current densities correspond to small cores.
For forced cooling, the permissible current density depends on the intensity of cooling.
        6. If the output voltage stabilization is selected, the first output is the leading one. And it must be assigned to the output with the highest consumption.
The remaining outputs are counted according to the first.
For real stabilization of all outputs, a group stabilization inductor should be used.
        7. With unipolar rectification, in spite of the greater copper consumption, the rectification scheme with an average point has the advantage, since the losses on two diodes will be 2 times less than on four diodes in a bridge circuit.
         8. For correct operation of the inductor in the rectifier after the diodes, there should be no capacitors in front of the inductor! Even a small size.
         9. On the number of turns of the windings in the calculation results, the tooltips with the number of layers occupied by the winding are placed.
        10. On the numbers of wires in the windings in the calculation results,  the tooltips with the current density in the winding are placed.
        11. At the minimum, nominal and maximum output voltages, the tooltips are placed with the voltage amplitude on the secondary windings, respectively, at the minimum, nominal and maximum supply voltages.
        12. The tooltips with fill factor for minimum, nominal and maximum input voltage are placed on the wire diameter.
        13. If stabilization operation is selected, then the minimum and maximum output voltages are absent and, accordingly, are not shown.

 RECOMMENDED ORDER OF WORK:
1. Decide on the circuit of the converter and rectifier. Define their configuration in the source data. See the tab "Show conversion and rectification schemes."
2. Decide on the power of the converter. Set the possible limits of the input power supply of the converter, taking into account fluctuations in the line. User can select AC or DC input voltage.
3. Decide on the availability of output stabilization through PWM. In the case when the circuit provides feedback from the main secondary winding (output 1) to the PWM controller, select "Stabilization - yes", if there is no such feedback, then "Stabilization - no". In the absence of the indicated stabilization, the magnitude of the magnetic induction amplitude increases with the input voltage increase. If there is stabilization, the induction amplitude and losses in the magnetic core are stable, so it is possible to use a smaller magnetic core.
4. Set the winding sequence of the primary winding.
5. Set the output voltages and currents, the voltage drop across the rectifier diodes. The program provides up to three outputs. A bipolar output (bipolar rectifier with a midpoint) counts as one.
6. Set the limit value of the pulse fill factor (depends on the controller used and the availability of PWM).
7. Set the channel resistance of the power switches (used for field effect transistors) of the converter or the voltage drop (in the open state, used for bipolar transistors or IGBTs) on these switches.
8. Set the window fill factor. It characterizes by the filling of a torus hole with a wire. If it is practically not possible to wind the estimated number of turns, the fill factor should be reduced and the calculation repeated. And vice versa, if it is possible to lay the windings with a higher fill factor, it is possible to use smaller and cheaper core.
9. Set the current density. It determines the diameter of the wire. Low values ??reduce losses in the winding, but increase the size of the magnetic core, because in a small magnetic core these windings cannot be placed. High density values ??increase winding loss and overall overheating. But at the same time, it is often possible to use a smaller size of the magnetic core. Usually for a specific task there is an optimum. Therefore, it is recommended to perform a series of calculations, changing the set density value by a step. Say, from 4 to 10 in steps of 1. For some density value from the interval, a reasonable overheating will occur at a minimum size. Further, when specifying the calculations in the “Optimization” group, it is possible to change the diameters of the winding wires in an optimal way, evaluating the total overheating, i.e. use a different current density in each winding.
10. Set the limit ambient temperature.
11. Set the number of the magnetic cores in the package. Sometimes it is required to use several magnetic cores to increase power or for other tasks (for example, use two small cores instead of a large size).
12. Set the expected transformer temperature. For the MSTN series (plastic container), the temperature limit is 155 degrees C. The user can set the lower values of the expected temperature if the high temperature of the transformer is not desirable for some reason. When calculating the project, the program will not exceed this set value.
13. Set the maximum Rac / Rdc. With a small value of this ratio, the program will use a large number of wires in parallel to reduce the skin effect. This is not always optimal for design reasons and for reasons of minimizing dimensions. With a large value, the minimum value of the wires in the winding will be obtained, but at the same time, it is possible that the use of the wire will be suboptimal due to the skin effect. In particular, it is possible to simulate the use of special high-frequency stranded wires with insulation of each core. To do this, set the number of cores and the diameter of the cores in the Optimization group. The use of a rectangular wire profile is not provided in the program.
14. Press the button "Automatic selection of the magnetic core and its calculation." The program will select the magnetic core from a given series and give the calculated results.
15. Transformer design is a complex task with many variables. Each user has their own optimum criteria. For one, this is the price and size, for the other, maximum efficiency, for the third, the minimum leakage inductance and parasitic parameters (in order to reduce electromagnetic interference and reduce damping elements of high-frequency emissions - dampers), for the fourth, minimal overheating, for the fifth, manufacturability and minimum labor and so on. And more often it is a combination of criteria. Therefore, the result of the calculation can be considered only as the initial stage of the project. The main work is performed by the user in the "Optimization" group. The user can select a smaller or larger size of the magnetic core (or specify the type rating), change the diameters of the wires of the windings, the number of wires in the windings, the number of turns of the primary winding. By consciously changing this data, and observing the change in individual optimization criteria, you can significantly improve the project according to your requirements.
16. A completed project can be saved to disk for later download.
17. The final verification and refinement of the project are carried out by practical testing in a real scheme.

You can forward the noticed errors, your questions, comments and suggestions to edf01@yandex.ru.