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Alejandro Rodríguez

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Alejandro Rodríguez last won the day on November 27 2019

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  1. Dear Mandy, Thank you for this suggestion. I will verify Flux documentation and, eventually, update it. Best regards, Alejandro
  2. Dear Mandy, Actually, most of your assumptions are right: the resistance value is calculated by Flux using the equation R=rho*l/A. What it is not right is that, in this case, the value entered in “resistance formula” does not matter. In fact, total resistance associated with stranded coil conductor is the addition of two terms: the one calculated using R=rho*l/A and the value introduced by the user. In other words, value introduced in “resistance formula” field is an additional source of resistance added to the one obtained from geometrical and material properties. In your case, the resistance calculated from geometry is 6 mohm, as can be deduced from your outputs. If evaluated resistance of the non-meshed coils is only 3mohm and not 6 it is maybe due to the existence of symmetries/periodicities or maybe because two coils are associated to the same stranded coil conductor. From a practical point of view: If you only want to take into account the value calculated by Flux from material and geometrical properties (i.e., R=rho*l/(F*A), where F is the fill factor) you should write 0 in “resistance formula” field. On the contrary, if you want to establish yourself the resistance in spite of geometry/material properties, the best way to do so is not to fill the field “material” when defining the non-meshed coil. Best regards, Alejandro
  3. Hello Berke, Please, find attached a pdf which explains clearly the differences between Bertotti and LS methods and how to take advantage of them in Altair Flux. The reason why you cannot use the first two time steps to calculate iron losses is that it uses derivatives and to obtain the derivative in point N you need the variable values in previous points (N-1 and N-2). Best regards, Alejandro Iron_losses-Altair_Flux-Bertotti_LS_models.pdf
  4. Hello Ruud, Actually the problem is that the compiler you are using (MinGW) is not compatible, that is why you are having this issue. This coupling have been tested using Visual Studio 2005 as C compiler. Newer versions of Visual Studio should work fine, also. Please, try again using Visual Studio as compiler. Best regards.
  5. Hello Ruud, I am afraid that, unfortunately, there is no way to control FluxMotor from Matlab. Best regards,
  6. Hello Xiaodong, You are welcome. Yes, you can use this topic to share your project (if you do not have confidentiality issues) or you can send a mail to your local support account. Best regards,
  7. Hello Mandy, I understand your method to calculate cogging torque but I think it is rather difficult to applicate, since it implies to numerically calculate stored energy (not always an easy task) and them derivate it, which is also a tricky process from a numerical point of view. In other words, to assure the accuracy of your results you will need a really dense mesh (especially in the areas where a high quantity of magnetic energy is expected to be stored) and a small time step to be sure that your derivatives have enough precision. These two factor may lead the simulation time to skyrocket. Actually, seeing your results it seems that you need both, a denser mesh and smaller time step. I am not an expert about torque components separation, but I can suggest you to check this paper, it may help you in your research. [2014 Chen] X. Chen, J. Wang et al., “Reluctance torque evaluation for interior permanent magnet machines using frozen permeability”, 7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014. (https://ieeexplore.ieee.org/document/6836779 ) Hope this helps. Best regards,
  8. Hello Xiaodong, In fact, this error may have two different causes: or the section of your coil is not constant or you have points in the lines defining your trajectory. Since coil is defined through surface extrusion, I guess you are in the second case: the solution is to define new cross-section faces relying this points I think that you should be able to define your non-meshed coils in a way that their geometry will be nearly the same you have in your meshed coils. Actually, depending on the application and the specific geometry, differences in coil’s shape could lead to important differences in magnetic behaviour (in fact, they can play a major role in local effects). In conclusion, in a general case, you should not neglect differences in geometry, especially in the areas where coil is near ferromagnetic components. I am sorry, but for further help you have to send us your project in order to check it. Best regards,
  9. Hello Natto, Actually, it really depends on your application definition. In a general way, resistances in stranded coil conductor components associated to face/volume regions are automatically evaluated during resolution taken into account coil area, length, material resistivity at working conditions, fill factor and number of turns (see image). Additionally, specific simulations can be performed to estimate resistance in working conditions (temperature and current distribution may play a major role in resistance values). Since you will obtain all electrical values you can evaluate real resistance during postprocessing. Anyway, for most of applications, a critical variable for coil resistance calculus is the fill factor that is mostly estimated through practical measures. Best regards, Alejandro
  10. Hello Louis, You will find Berttoti coefficient’s excel file in this path: [FLUX INSTALLATION DIRECTORY]\flux\Flux\DocExamples\Tools\BertottiLossesCoefficients\BertottiLossesCoefficients.xls By default, [FLUX INSTALLATION DIRECTORY] is C:\Program Files\Altair\2019_1 for version 2019.1. Best regards, Alejandro
  11. Hello Ruud, Sorry for this late answer. Actually, the easiest way to perform your calculus with movement is to use a support, typically a path or a 2D grid. In both cases you can associate a mechanical set to the support. If I have understood correctly your case, you can define your path in the mechanical set of the rotor. Once the project have been solved you can directly represent the normal (or tangential) component to this path. The “Curve -> 2D curve (Path)” menu allows to choose the normal component of your vector quantity (e.g., flux density) directly, no need to define an specific coordinate system. Hope this helps. Best regards,
  12. Hello Tehran, Actually, the multi-static kinematic model, the moving part of the device is not moving. The computation of the electromagnetic field is carried out for various relative positions of moving and fixed parts, chosen in the scenario. This model performs a set of Magneto Statics computations. Therefore, computation of the electromagnetic field is not the same used in real moving mechanical sets, since it does not take into consideration the dynamic equation. Use this model is equivalent to run a parameterized study where the position of the moving part is a varying parameter, that means that the variation in rotor position should be established in the scenario definition -> control of parameters. The torque calculated in this way is equivalent to the torque experimented by the rotor as a function of its position (ANGPOS_ROTOR ), so the concept is the same that using a rotating mechanical set at imposed speed and the results should be quite close. Anyway, I strongly advise you to use imposed speed instead, since dynamic equations are more accurate that magneto static ones when movement is involved. Best regards,
  13. Hello Sandesh, I am not completely sure if I understand your questions: I think that you want to compute global radial force over the stator for each rotor position and for each current, is this right? In this case the simplest and more straightforward solution is to use a sensor defined as you in the image attached where you should choose as lines of interest the borders between the teeth and the airgap (as shown). CYLIN_REF makes reference to a centred cylindrical-coordinates systems as it is shown in the second picture (i.e., it will established your reference to calculate the radial part of the force). If, on the contrary, you want to know the local forces over the stator border with the airgap (which is usually the case to do NVH analysis) I advise you to follow Flux supervisor’s example that you will find in 2D, Open example->Multiphysics->Vibroacustic analysis via OptiStruct . Best regards.
  14. Hello Tehran, Actually, you have several possibilities depending of your physics and your specific needs. The most simple one, only for linear problems with no magnetic saturation (i.e., rotor and stator modelled as ideal materials), is to use an specific sensor which measures inductance (it divides the total flux embraced by the coil between the current carried by this same coil, which is, in fact, an accurate definition of inductance for magnetic linear problems). You can find more accurate and sophisticated way to calculate this value for electric machines in our tutorial in 2D: Brushless IPM motor (embedded magnets), section 7.3. You will find it in the supervisor : Open example -> Technical tutorials -> Brushless IPM motor (embedded magnets) ->Computation of inductances and static torque. Another approach to simulate inductance in electric machines is to use the macro ComputeInductanceMatrix, you can load it into your project from Macros_Flux2D_Postproc. This is an advanced approach which uses frozen permeability techniques to take into account material saturation caused by the magnets where the machine is in working conditions. Please, notice that this macro can take some time to compute since it runs several simulations to accurately represents this physical phenomena. I hope the proposed documentation helps you with your inductance calculus. Please, do not hesitate to return to me in case you need further information about these topics. Best regards.
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