{"id":4275,"date":"2013-02-08T09:00:33","date_gmt":"2013-02-08T14:00:33","guid":{"rendered":"https:\/\/blogs.mathworks.com\/pick\/?p=4275"},"modified":"2018-11-24T12:19:22","modified_gmt":"2018-11-24T17:19:22","slug":"thermal-effects-in-electrical-models","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/pick\/2013\/02\/08\/thermal-effects-in-electrical-models\/","title":{"rendered":"Thermal Effects in Electrical Models"},"content":{"rendered":"<div xmlns:mwsh=\"https:\/\/www.mathworks.com\/namespace\/mcode\/v1\/syntaxhighlight.dtd\" class=\"content\">\r\n   <introduction>\r\n      <p><a href=\"https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/authors\/32620\">Greg's<\/a> pick this week is <a href=\"https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/35980-loss-calculation-in-a-buck-converter-using-simpowersystems-and-simscape\">Loss Calculation in a Buck Converter Using SimPowerSystems and Simscape<\/a> by <a href=\"https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/authors\/216973\">Pierre Giroux<\/a><\/p>\r\n      <p>There are several reasons that lead me to choose this submission. It:<\/p>\r\n      <div>\r\n         <ol>\r\n            <li>demonstrates the ability to mix modeling different physical domains in the Simulink environment;<\/li>\r\n            <li>is a good reference for users who are looking to do some efficiency studies on switching power supplies; and<\/li>\r\n            <li>is a well laid out model with supporting documentation.<\/li>\r\n         <\/ol>\r\n      <\/div>\r\n   <\/introduction>\r\n   <h3>Contents<\/h3>\r\n   <div>\r\n      <ul>\r\n         <li><a href=\"#1\">Heat, Please Disperse. There is Nothing to See Here!<\/a><\/li>\r\n         <li><a href=\"#2\">What Can You Investigate with Switching Models that Include Thermal Effects?<\/a><\/li>\r\n         <li><a href=\"#3\">How Does Pierre Include Thermal Effects?<\/a><\/li>\r\n         <li><a href=\"#4\">Should You Always Include Thermal Effects in Electrical Models?<\/a><\/li>\r\n      <\/ul>\r\n   <\/div>\r\n   <h3>Heat, Please Disperse. There is Nothing to See Here!<a name=\"1\"><\/a><\/h3>\r\n   <p>Much of the time I spend in the field with our customers focuses on industrial automation applications. In general this means\r\n      managing electrical power conversion and distribution, as well as controlling motors.  In order to apply digital control to\r\n      these types of applications you normally have to use some sort of power electronics like a <a href=\"http:\/\/en.wikipedia.org\/wiki\/Power_MOSFET\">MOSFET<\/a> or <a href=\"http:\/\/en.wikipedia.org\/wiki\/Insulated_gate_bipolar_transistor\">IGBT<\/a> to apply the output from the digital control hardware to the system circuitry.\r\n   <\/p>\r\n   <p>For power conversion, heat is an important concern. Any heat generated by an electrical system represents an electrical power\r\n      loss, and for electrical power converters, a reduction in efficiency. In addition, heat that gets generated must be managed\r\n      to prevent to <a href=\"http:\/\/en.wikipedia.org\/wiki\/Power_MOSFET#Maximum_temperature\">degradation of the power electronics<\/a> or surrounding components.\r\n   <\/p>\r\n   <h3>What Can You Investigate with Switching Models that Include Thermal Effects?<a name=\"2\"><\/a><\/h3>\r\n   <p>Pierre provides a couple of possible scenarios. He varies both the electrical load, and the frequency at which the power electronic\r\n      gates are opened and closed.\r\n   <\/p>\r\n   <p>The increase in electrical load at 2 seconds results in a higher power output from the amplifier.<\/p>\r\n   <p><img decoding=\"async\" vspace=\"5\" hspace=\"5\" src=\"https:\/\/blogs.mathworks.com\/pick\/files\/electrical_power_load1.png\"> <\/p>\r\n   <p>This leads to an increase in temperature of the power electronic devices, and an increase in operating losses.<\/p>\r\n   <p>Reducing the switching frequency from 10 kHz to 2.5 kHz at 2.5 seconds permits more time for the power electronic devices\r\n      to dissipate heat, and so the device temperature drops and operating losses recover nicely.\r\n   <\/p>\r\n   <p><img decoding=\"async\" vspace=\"5\" hspace=\"5\" src=\"https:\/\/blogs.mathworks.com\/pick\/files\/junction_temperature1.png\"> <\/p>\r\n   <p><img decoding=\"async\" vspace=\"5\" hspace=\"5\" src=\"https:\/\/blogs.mathworks.com\/pick\/files\/power_losses1.png\"> <\/p>\r\n   <h3>How Does Pierre Include Thermal Effects?<a name=\"3\"><\/a><\/h3>\r\n   <p>Pierre leverages the capability to mix different physical modeling domains in the Simulink environment, as well as the capability\r\n      to inject his desired equations for computing losses into the simulation.\r\n   <\/p>\r\n   <p>\r\n\r\n\r\n\r\n<! TABLE HERE>\r\n<table width=\"100%\" style=\"background-color:rgb(255,255,255)\" border=\"0\" cellpadding=\"0\" cellspacing=\"0\" alignment=\"left\">\r\n\r\n<\/td><\/tr>\r\n<tr>\r\n<td>   <b>Electrical Model<\/b>           <\/td>   <td>     <img decoding=\"async\" src=\"https:\/\/blogs.mathworks.com\/pick\/files\/electrical_model1.png\" width = 300>           <\/td>\r\n<\/tr>\r\n<!DIVIDER>\r\n<tr><td colspan=\"2\">\r\n__________________________________________________________________________\r\n<tr>\r\n<td>   <b>Thermal Management Model<\/b>  <\/td>   <td>     <img decoding=\"async\" src=\"https:\/\/blogs.mathworks.com\/pick\/files\/thermal_management_model1.png\" width = 500>    <\/td>\r\n<\/tr>\r\n<!DIVIDER>\r\n<tr><td colspan=\"2\">\r\n__________________________________________________________________________\r\n\r\n<tr>\r\n<td>   <b>Thermal Model<\/b>  <\/td>   <td>     <img decoding=\"async\" src=\"https:\/\/blogs.mathworks.com\/pick\/files\/thermal_model1.png\" width = 500>    <\/td>\r\n<\/tr>\r\n<!DIVIDER>\r\n<tr><td colspan=\"2\">\r\n__________________________________________________________________________\r\n\r\n<\/table>\r\n\r\n\r\n   <\/p>\r\n   <p>The electrical modeling is done using <a href=\"https:\/\/www.mathworks.com\/products\/simscape-electrical.html\">Simscape Electrical<\/a>. The management of the generated heat leverages the basic libraries in <a title=\"https:\/\/www.mathworks.com\/products\/simscape-e (link no longer works)\">Simscape<\/a>. Pierre uses the various measurement outputs of the IGBT models to compute the amount of heat to inject into the thermal\r\n      management model using linear state-space blocks from the Simulink library.\r\n   <\/p>\r\n   <h3>Should You Always Include Thermal Effects in Electrical Models?<a name=\"4\"><\/a><\/h3>\r\n   <p>In short the answer is &#8220;no!&#8221;  In many cases it is not necessary. An electrical model that includes thermal effects could be\r\n      used to identify appropriate switching frequencies for the power electronics and controller, or general loading capacities\r\n      of the power amplifier. You can then use this information for controller design or including more dynamic loading of the power\r\n      amplifier.\r\n   <\/p>\r\n   <p>In general you want to use the simplest model you can for a particular design purpose.  Higher fidelity models are great for\r\n      determining operating limits, but can bog down simulation speed for system simulations.\r\n   <\/p>\r\n   <p><b>Comments<\/b><\/p>\r\n   <p>If you would like to leave any comments regarding this post, please click <a href=\"https:\/\/blogs.mathworks.com\/pick\/?p=4275#respond\">here<\/a>.\r\n   <\/p><script language=\"JavaScript\">\r\n<!--\r\n\r\n    function grabCode_6a5fe30eb0b7461098c75bc5831a0a75() {\r\n        \/\/ Remember the title so we can use it in the new page\r\n        title = document.title;\r\n\r\n        \/\/ Break up these strings so that their presence\r\n        \/\/ in the Javascript doesn't mess up the search for\r\n        \/\/ the MATLAB code.\r\n        t1='6a5fe30eb0b7461098c75bc5831a0a75 ' + '##### ' + 'SOURCE BEGIN' + ' #####';\r\n        t2='##### ' + 'SOURCE END' + ' #####' + ' 6a5fe30eb0b7461098c75bc5831a0a75';\r\n    \r\n        b=document.getElementsByTagName('body')[0];\r\n        i1=b.innerHTML.indexOf(t1)+t1.length;\r\n        i2=b.innerHTML.indexOf(t2);\r\n \r\n        code_string = b.innerHTML.substring(i1, i2);\r\n        code_string = code_string.replace(\/REPLACE_WITH_DASH_DASH\/g,'--');\r\n\r\n        \/\/ Use \/x3C\/g instead of the less-than character to avoid errors \r\n        \/\/ in the XML parser.\r\n        \/\/ Use '\\x26#60;' instead of '<' so that the XML parser\r\n        \/\/ doesn't go ahead and substitute the less-than character. \r\n        code_string = code_string.replace(\/\\x3C\/g, '\\x26#60;');\r\n\r\n        author = 'Brett Shoelson';\r\n        copyright = 'Copyright 2013 The MathWorks, Inc.';\r\n\r\n        w = window.open();\r\n        d = w.document;\r\n        d.write('<pre>\\n');\r\n        d.write(code_string);\r\n\r\n        \/\/ Add author and copyright lines at the bottom if specified.\r\n        if ((author.length > 0) || (copyright.length > 0)) {\r\n            d.writeln('');\r\n            d.writeln('%%');\r\n            if (author.length > 0) {\r\n                d.writeln('% _' + author + '_');\r\n            }\r\n            if (copyright.length > 0) {\r\n                d.writeln('% _' + copyright + '_');\r\n            }\r\n        }\r\n\r\n        d.write('<\/pre>\\n');\r\n      \r\n      d.title = title + ' (MATLAB code)';\r\n      d.close();\r\n      }   \r\n      \r\n-->\r\n<\/script><p style=\"text-align: right; font-size: xx-small; font-weight:lighter;   font-style: italic; color: gray\"><br><a href=\"javascript:grabCode_6a5fe30eb0b7461098c75bc5831a0a75()\"><span style=\"font-size: x-small;        font-style: italic;\">Get \r\n            the MATLAB code \r\n            <noscript>(requires JavaScript)<\/noscript><\/span><\/a><br><br>\r\n      Published with MATLAB&reg; R2012b<br><\/p>\r\n<\/div>\r\n<!--\r\n6a5fe30eb0b7461098c75bc5831a0a75 ##### SOURCE BEGIN #####\r\n%% Thermal Effects in Electrical Models\r\n%\r\n% <https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/authors\/32620\r\n% Greg's> pick this week is\r\n% <https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/35980-loss-calculation-in-a-buck-converter-using-simpowersystems-and-simscape\r\n% Loss Calculation in a Buck Converter Using SimPowerSystems and Simscape>\r\n% by <https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/authors\/216973\r\n% Pierre Giroux>\r\n% \r\n% There are several reasons that lead me to choose this submission. It:\r\n% \r\n% # demonstrates the ability to mix modeling different physical domains in\r\n% the Simulink environment;\r\n% # is a good reference for users who are\r\n% looking to do some efficiency studies on switching power supplies; and  \r\n% # is a well laid out model with supporting documentation.\r\n% \r\n\r\n%% Heat, Please Disperse. There is Nothing to See Here!\r\n% Much of the time I spend in the field with our customers focuses on\r\n% industrial automation applications. In general this means managing electrical\r\n% power conversion and distribution, as well as controlling motors.  In\r\n% order to apply digital control to these types of applications you\r\n% normally have to use some sort of power electronics like a\r\n% <http:\/\/en.wikipedia.org\/wiki\/Power_MOSFET MOSFET> or\r\n% <http:\/\/en.wikipedia.org\/wiki\/Insulated_gate_bipolar_transistor IGBT> to\r\n% apply the output from the digital control hardware to the system\r\n% circuitry.\r\n%\r\n% For power conversion, heat is an important concern. Any heat\r\n% generated by an electrical system represents an electrical power loss,\r\n% and for electrical power converters, a reduction in efficiency. In\r\n% addition, heat that gets generated must be managed to prevent to\r\n% <http:\/\/en.wikipedia.org\/wiki\/Power_MOSFET#Maximum_temperature\r\n% degradation of the power electronics> or surrounding components.\r\n\r\n%% What Can You Investigate with Switching Models that Include Thermal Effects?\r\n% Pierre provides a couple of possible scenarios. He varies both the\r\n% electrical load, and the frequency at which the power electronic\r\n% gates are opened and closed.\r\n%\r\n% The increase in electrical load at 2 seconds results in a higher power\r\n% output from the amplifier.\r\n% \r\n% <<electrical_power_load.png>>\r\n% \r\n% This leads to an increase in temperature of the power electronic devices,\r\n% and an increase in operating losses.\r\n%\r\n% Reducing the switching frequency from 10 kHz to 2.5 kHz at 2.5 seconds\r\n% permits more time for the power electronic devices to dissipate heat, and\r\n% so the device temperature drops and operating losses recover nicely.\r\n%\r\n% <<junction_temperature.png>>\r\n%\r\n% <<power_losses.png>>\r\n%\r\n\r\n%% How Does Pierre Include Thermal Effects?\r\n% Pierre leverages the capability to mix different physical modeling\r\n% domains in the Simulink environment, as well as the capability to inject\r\n% his desired equations for computing losses into the simulation.\r\n%\r\n% <html>\r\n% <table width=\"100%\">\r\n%     <tr style=\"background-color: #FFFFFF; text-align: center; color: #FFFFFF\">\r\n%         <td><b>Electrical Model<\/b><\/td>\r\n%         <td><img decoding=\"async\" src=\"electrical_model.png\" width = 300><\/td>\r\n%     <\/tr>\r\n%     <tr style=\"background-color: #FFFFFF; text-align: center; color: #FFFFFF\">\r\n%         <td><b>Thermal Management Model<\/b><\/td>\r\n%         <td><img decoding=\"async\" src=\"thermal_management_model.png\" width = 500><\/td>\r\n%     <\/tr>\r\n%     <tr style=\"background-color: #FFFFFF; text-align: center; color: #FFFFFF\">\r\n%         <td><b>Thermal Model<\/b><\/td>\r\n%         <td><img decoding=\"async\" src=\"thermal_model.png\" width = 500><\/td>\r\n%     <\/tr>\r\n% <\/table>\r\n% <\/html>\r\n%\r\n% The electrical modeling is done using\r\n% <https:\/\/www.mathworks.com\/products\/simscape-electrical.html Simscape Electrical>. The\r\n% management of the generated heat leverages the basic libraries in\r\n% <https:\/\/www.mathworks.com\/products\/simscape\/ Simscape>. Pierre uses the\r\n% various measurement outputs of the IGBT models to compute the amount of\r\n% heat to inject into the thermal management model using linear state-space\r\n% blocks from the Simulink library.\r\n\r\n%% Should You Always Include Thermal Effects in Electrical Models?\r\n% In short the answer is \u00e2\u20ac\u0153no!\u00e2\u20ac\ufffd  In many cases it is not necessary. An\r\n% electrical model that includes thermal effects could be used to identify\r\n% appropriate switching frequencies for the power electronics and\r\n% controller, or general loading capacities of the power amplifier. You can\r\n% then use this information for controller design or including more dynamic\r\n% loading of the power amplifier.\r\n%\r\n% In general you want to use the simplest model you can for a particular\r\n% design purpose.  Higher fidelity models are great for determining\r\n% operating limits, but can bog down simulation speed for system\r\n% simulations.\r\n\r\n%%\r\n% *Comments*\r\n%\r\n% If you would like to leave any comments regarding this post, please click \r\n% <https:\/\/blogs.mathworks.com\/pick\/?p=4275#respond here>. \r\n\r\n##### SOURCE END ##### 6a5fe30eb0b7461098c75bc5831a0a75\r\n-->","protected":false},"excerpt":{"rendered":"<div class=\"overview-image\"><img src=\"https:\/\/blogs.mathworks.com\/pick\/files\/thermal_model1-1.png\" class=\"img-responsive attachment-post-thumbnail size-post-thumbnail wp-post-image\" alt=\"\" decoding=\"async\" loading=\"lazy\" \/><\/div><p>\r\n   \r\n      Greg's pick this week is Loss Calculation in a Buck Converter Using SimPowerSystems and Simscape by Pierre Giroux\r\n      There are several reasons that lead me to choose this submission.... <a class=\"read-more\" href=\"https:\/\/blogs.mathworks.com\/pick\/2013\/02\/08\/thermal-effects-in-electrical-models\/\">read more >><\/a><\/p>","protected":false},"author":44,"featured_media":8573,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[16],"tags":[],"_links":{"self":[{"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/posts\/4275"}],"collection":[{"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/users\/44"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/comments?post=4275"}],"version-history":[{"count":93,"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/posts\/4275\/revisions"}],"predecessor-version":[{"id":10324,"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/posts\/4275\/revisions\/10324"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/media\/8573"}],"wp:attachment":[{"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/media?parent=4275"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/categories?post=4275"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/pick\/wp-json\/wp\/v2\/tags?post=4275"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}