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 Label | Tab 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 Label | Tab 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
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