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CEDRAT News - N° 66 - June 2014 Identify supply to establish a predefined profile of temperature with Flux®. Cyril Favre - CEDRAT. M acros have been available with Flux since 2008. Macros allow sets of commands to be executed using PyFlux command language, after questioning the user. The questions can include the possibility to graphically select Flux components such as points, face regions, etc. as well as existing files opening a windows explorer. The goal of a macro is to automate tasks, making Flux easier to use and to add new functionalities. &ŝŐƵƌĞϯ͗/ŶƉƵƚŽĨ ƚŚĞŵĂĐƌŽ͘ In this part, we will present two macros available for induction heating process. These macros can be used for steady state AC application coupled with transient thermal application. The results of the macros applied on a test case will also be presented. The magneto-thermal test case represents a pipe heated with an inductor composed of solid conductors. The inductor is supplied with a voltage source. The RMS value of the voltage source is defined thanks to the parameter named VOLTAGE. It is the parameter piloted by the macros. The geometry of the test case is presented in figure 1. The circuit used for the test case is presented in figure 2. &ŝŐƵƌĞϰ͗tŽƌŬŝŶŐƉƌŝŶĐŝƉůĞŽĨƚŚĞŵĂĐƌŽ͘ &ŝŐƵƌĞϭ͗'ĞŽŵĞƚƌLJŽĨƚŚĞƚĞƐƚĐĂƐĞ The Input of the macro “FindOutSupplyForGivenTemperature.pfm“ is presented in figure 3. When the macro is run, a first computation is done with the initial value defined by the user in the interface of the macro. At the end of the computation, we compute the temperature of the last step of the defined scenario. If the temperature is not in the range defined by the precision, the macro will restart the computation with a new value for the supply. The macro will iterate until it finds out the supply that allows reaching a specific temperature. Once the value of the supply is found out, an inspection is added to check if the obtained value is not higher than the maximum value of the source. The working principle of the macro is provided in figure 4. At the end of the computation, when the supply value is found out, the curve of the temperature versus time is created. A text file is also created in the working directory. For each iteration done, this text file contains the target temperature, the temperature reached as well as the value of the voltage for the iteration. The macro has been applied in the test case presented in the first part, with the setting presented in figure 3. The value of the voltage source needed to reach a temperature of 600°C in 50 seconds is 9.5 VRMS and 30.37 ARMS of current. With this supply, the temperature reached is 599.88°C. &ŝŐƵƌĞϮ͗ŝƌĐƵŝƚŽĨƚŚĞƚĞƐƚĐĂƐĞ &ŝŐ ƌĞ Ϯ ŝƌĐ ŝƚ ŽĨ ƚŚ Find the supply that gives a target temperature The goal of this macro is to search the value of the supply source (it can be current or voltage source) to obtain a desired temperature at the end of a predefined scenario. The inputs of the macro are: • The scenario to solve • The target temperature • The sensor allowing to compute the temperature • The I/O parameter to be varied (VOLTAGE in this example) • The maximal value of the input parameter • Precision expected on the temperature • The maximum number of iterations allowed to find the value of the supply that gives the target temperature. &ŝŐƵƌĞϱ͗dĞŵƉĞƌĂƚƵƌĞǀĞƌƐƵƐƟŵĞ͘ &ŝŐƵƌĞϲ͗/ƚĞƌĂƟŽŶƐĚŽŶĞƚŽƌĞĂĐŚƚŚĞƚĂƌŐĞƚĞĚ ƚĞŵƉĞƌĂƚƵƌĞ͘ (see continued on page 19) - 18 - CEDRAT News - N° 66 - June 2014 Figure 5 represents the curve of the temperature versus time obtained and figure 6 represents the text file containing all the iterations done by the macro. Control supply to match a given result The goal of this second macro is to control step by step the value of the supply (RMS value of voltage or current source) to have a temperature matching a given result. This macro allows predicting the supply in order to obtain a given profile of temperature. The inputs of the macro “ControlSupplyToMatchAGivenResults.pfm “are: • The parameter to pilot • The variation parameter defining the output (I/O Parameter or sensor) • A tabulated parameter describing the desired profile of temperature • The value of the time step • The end time of the scenario • The precision to reach on the temperature • The name of the scenario to create • The maximum number of iterations to find the value of the supply for each time step The figure 7 represents the input of the macro: The working principle used for each time step to find the RMS value of the supply that gives the target temperature which is identical to the method used in the previous macro (see figure 4). This method is repeated for each time step. At the end of the macro run, the scenario defined by the user is solved; the temperature and the value of the supply can be displayed thanks to the 2D curve. During the running of the macro, a text file is automatically created for each time step to store the iteration used to find the supply that gives the target temperature. The macro has been applied in the test case presented in the first part, with the setting presented in figure 7 and with the temperature profile of the figure 8. The temperature versus time obtained thanks to the macro is presented in figure 10. We notice the target temperature and the obtained temperature are superimposed. The RMS value of the voltage applied to obtain the desired temperature is presented in figure 11. &ŝŐƵƌĞϭϬ͗dĂƌŐĞƚĞĚƚĞŵƉĞƌĂƚƵƌĞΘƚĞŵƉĞƌĂƚƵƌĞŽďƚĂŝŶĞĚ ;ĐƵƌǀĞƐĂƌĞƐƵƉĞƌŝŵƉŽƐĞĚͿ͘ &ŝŐƵƌĞϳ͗/ŶƉƵƚŽĨƚŚĞŵĂĐƌŽ͘ Before running the macro, the user has to define the profile of expected temperature. It should be done thanks to a tabulated I/O parameter. An example of tabulated parameter used to define the temperature profile is presented in figure 8. The curve versus time of the tabulated parameter is presented in figure 9. &ŝŐƵƌĞϭϭ͗ZD^ǀĂůƵĞŽĨƚŚĞǀŽůƚĂŐĞǀĞƌƐƵƐƟŵĞ͘ Conclusion &ŝŐƵƌĞϴ͗WƌŽĮůĞŽĨƚĞŵƉĞƌĂƚƵƌĞͲdĂďƵůĂƚĞĚ͘ Macro is a great asset of Flux 2D/3D. Macros are generally used to automate repetitive tasks or to build geometry with predefined input. But as shown in this article, macro allows to develop more complex functionalities with Flux. Thanks to the macro presented in this article we are able to pilot a scenario step by step and to iterate smartly on the value of the supply to obtain targeted results. In this case, macros replace manual iteration to find the correct value of the supply according to the temperature expected. Flux is delivered with a list of ready-defined macros. The full list of macros is available in the “C:\Cedrat\Extensions\Macros” directory, with the “macros_list_EN.pdf” file. You will find more macros on the CEDRAT gate (https://gate.cedrat.com). &ŝŐƵƌĞϵ͗WƌŽĮůĞŽĨƚĞŵƉĞƌĂƚƵƌĞͲ'ƌĂƉŚ͘ - 19 -