{"id":4829,"date":"2020-12-22T21:26:03","date_gmt":"2020-12-22T20:26:03","guid":{"rendered":"https:\/\/blogs.mathworks.com\/student-lounge\/?p=4829"},"modified":"2020-12-22T21:26:03","modified_gmt":"2020-12-22T20:26:03","slug":"using-physical-modeling-to-design-and-simulate-an-electric-vehicle","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/student-lounge\/2020\/12\/22\/using-physical-modeling-to-design-and-simulate-an-electric-vehicle\/","title":{"rendered":"Using Physical Modeling to Design and Simulate an Electric Vehicle"},"content":{"rendered":"

Today’s blog post is written by Veer Alakshendra<\/a>, Education Technical Evangelist on the Student Competition team at MathWorks. In this blog he talks about\u00a0how to\u00a0<\/span>model and simulate an electric vehicle\u00a0<\/span>using MATLAB and Simulink.<\/span><\/p>\n

Introduction<\/h2>\n

Modeling is a way to create a virtual representation of a real-world system that includes software and hardware.\u00a0<\/span>\u00a0<\/span>It<\/span>\u00a0is valuable for<\/span>\u00a0<\/span>formula student\u00a0<\/span>testing conditions that might be difficult to reproduce with hardware prototypes alone, especially in the early phase of the design process when hardware may not be available.<\/span>\u00a0<\/span><\/p>\n

To model the electric vehicle, we will\u00a0<\/span>use the physical modeling approach<\/span>,<\/span>\u00a0which\u00a0<\/span>is a way\u00a0<\/span>of modeling and simulating systems that consist of real physical components. It employs a physical network approach, where\u00a0<\/span>Simscape<\/span><\/a>\u00a0blocks correspond to physical elements, such as\u00a0<\/span>gears<\/span>,\u00a0<\/span>tires<\/span>, and\u00a0<\/span>motors<\/span>.<\/span>\u00a0<\/span><\/p>\n

\"\"<\/p>\n

Battery Pack<\/h2>\n

The battery pack consists of various batteries connected in series. We have modeled each battery using an equivalent circuit, which is relatively a simple electrical circuit containing a voltage source and several resistors and capacitors.<\/p>\n

\"Cells

Fig 1. Cells in series<\/p><\/div><\/p>\n

Another\u00a0<\/span>important step while modeling a battery is\u00a0<\/span>choosing the appropriate parameters of the physical blocks\u00a0<\/span>so that it<\/span>\u00a0<\/span>respond<\/span>s<\/span>\u00a0as similarly as possible as a physical battery cell<\/span>.<\/span>\u00a0<\/span>One possible\u00a0<\/span>way<\/span>\u00a0to determine\u00a0<\/span>these<\/span>\u00a0<\/span>parameters is\u00a0<\/span>by\u00a0<\/span>performing parameter estimation<\/span>\u00a0where we\u00a0<\/span>define the design<\/span>\u00a0<\/span>requirements, and cost function<\/span>s<\/span>\u00a0to\u00a0<\/span>optimize the model parameters<\/span>.<\/span>\u00a0To know more\u00a0<\/span>about<\/span>\u00a0how\u00a0<\/span>we have used this technique<\/span>\u00a0<\/span>to estimate the battery parameters,<\/span>\u00a0please check out this\u00a0<\/span>video titled, \u201c<\/span>Modeling Batteries Using Simulink and Simscape.<\/span><\/a>\u201d<\/span>\u00a0<\/span><\/p>\n

Buck Converter<\/span>\u00a0<\/span><\/h2>\n

To convert the\u00a0<\/span>high\u00a0<\/span>battery voltage to low voltage, we\u00a0<\/span>have\u00a0<\/span>used<\/span>\u00a0a DC-DC converter, specifically, a buck converter.<\/span>\u00a0<\/span><\/p>\n

In\u00a0<\/span>this case, we have used an\u00a0<\/span>Average-Value DC-DC Converter<\/span><\/a>\u00a0block<\/span>\u00a0<\/span>that represents a<\/span>\u00a0controlled average-value DC-DC converter.<\/span><\/p>\n

\"Buck

Fig 2. Buck converter<\/p><\/div><\/p>\n

Motor and Controller<\/h2>\n

The battery powers a \u00a0BLDC motor and is modeled using the BLDC<\/a> block available in Simscape Electrical<\/a>. We have used the datasheet to set the values of the block parameters under the stator, rotor, and mechanical tabs.<\/p>\n

To control the motor at different speeds, first, we sense the angular position using an Ideal Rotational Motion Sensor<\/a> block. Further, the angular position information is used by the hall sensor to determine when the rotor transitions from one sector to another. Next, we have built a commutation logic to compute the switching pattern for the three-phase inverter.<\/p>\n

\"Motor

Fig 3. Motor and controller<\/p><\/div><\/p>\n

To learn how to design motor controllers using Simscape, refer to this video<\/a>.<\/p>\n

Transmission<\/h2>\n

The transmission consists of the following components:<\/p>\n