Inductor is one of the basic component, however, i have find myself not knowing deep about it. With this competition, i get attracted to explore it further.

I want to explore the experiment via computer modeling and simulation. There are some possibility of modeling language and i will attempt on SPICE but also explore other like Modelica

specifically, i want to do this experiment by means of doing a multi physics modeling and simulation. By doing modeling & simulation, and validating its result against my fabricated simple circuit,

i believe it gives sufficiently good insight into inductor.

 

Why modeling? We are now in the edge where computer can be use to 'predict' the outcome of a circuit by running simulation. we can iterate the design parameters (e.g choice of components and input signal) until we get a desirable output, before building the prototype. Without modeling, we can only build the test circuit to validate and most often involving a painful trial and error or troubleshooting stage. For simple circuit, the difference of the two approach might be minimal, but as the circuit becomes more complex, modeling provide significant advantage, mostly

1) time saving vs trial and error

2) simulate test condition that is difficult or dangerous to do with real prototype.

 

Modeling Languages

When an inductor is involved, the circuit is analog in nature. There are few languages possible, and i list down some that i encountered myself.

 

SPICE should be the language that an electronic hobbyist and practitioner have encountered before. During undergraduate study, one must have been introduce to small signal and transient analysis

via a SPICE modeling software, like PSPICE. Most semiconductor company provides their own simulator, for example LTspice of Analog Device (after acquisition of Linear techology). such semiconductor provided

SPICE simulator is very popular among analog circuit designer as the IC of a specific can be simulated online for their design. Example of such usage is in power supply design.

 

Equation based

0 dimension equation can be used to model inductor. Example is this RLC circuit.

The equation we need to solve is derive as below

This can be modeled with OML (open matrix language) and i use Altair Compose with it

Compose can be downloaded and used for free at https://www.altair.com/mbd2019/

 

{tabbedtable} Tab LabelTab Content
0D Equation

OML model


% Define the system function

function dx = myrlc(t,x,v,R,L,C)

  dx1dt = x(2);

dx2dt = v/(L*C) - (R/L)*x(2) - x(1)/(L*C);

dx = [dx1dt; dx2dt];

end

 

% Define the circuit

v = 10; % volts - constant voltage source

R = 1.; % resistor

L = 1.; % inductor

C = 1.; % capacitor

 

 

options = odeset('RelTol',1.e-3,'AbsTol',[1.e-6,1.e-6]);

handle = @(t,x) myrlc(t,x,v,R,L,C);

[t,x] = ode45(handle, [0:0.1:20], [0;0], options);

 

% Plot the results

vc = x(:,1); % Vc

plot(t, vc);

legend('Vc');

title('RLC Circuit');

Plot

Plot


 

OML syntax is compatible with MATLAB. MATLAB can be used with Simscape language along with Simulink, however, it is not popular for analog circuit simulation.

 

For this work, i will perform simulation with SPICE language, using Altair Activate [1]. It is an open integration platform for modeling, simulating and optimizing multi-disciplinary systems-of-systems using inherent 1D block diagrams. One can simulate cross domain physics via its built in blocks and Modelica library – a collection of blocks describing the physical behavior of Electrical, Electromagnetic, Mechanical, Thermal components. SPICE netlist can be used for the electrical side. For my experiment, i plan to model a power electronics driver that can drive a mechanical device. Below is an example that i will adopt to use

 

Modeling in Altair Activate

for this blog #1, let's look at how to model in Activate.

First, a simple RLC circuit. there is a webinar and project file is provided. Go to https://learn.solidthinking.com/activate-videos/rlc-circuit-with-different-modeling-approaches/

SPICE can only be used with non free edition of Altair Activate

 

 

 

{tabbedtable} Tab LabelTab Content
Activate Block based

with basic blocks in Altair

Input                                                                                  

Output

Modelica

with Modelica blocks

output

SPICE

SPICE

Altair Activate make use of hyperspice, which is originally and SPICE model software acquired by Altair.

in the SPICE blocks, we can enter additional SPICE parameters

we get this output....which is different

More Examples

You can also explore some built in example

the screen below shows a DC-DC convertor and its output

 

 

 

Validation

In modeling and simulation, we will need to perform validation on the simulated result. We will make use of the inductor kit to build a RLC

circuit for validation.

 

 

PS : have just come back to work from week long lunar new year but immediate having a week long business trip. will update this simple validation result

further once reach home on 9 Feb and test with oscilloscope  >> this is now updated in Inductor Modeling and Simulation - Experimenting with Inductors - Part 2 of 2

 

References

[1] Altair Activate https://www.altair.com/mbd2019/downloads/AltairActivate_Datasheet_letter_0918.pdf

[2] part 2 of the blog Inductor Modeling and Simulation - Experimenting with Inductors - Part 2 of 2