Ansys Charge Plus: Air ESD Into Calibration Target Tutorial

Ansys Charge Plus: Air ESD Into Calibration Target Tutorial Hello everyone, this is Ander from Ozen Engineering. In this video, we will go through one of the ESD simulation tutorials available within Ansys EMC Plus and optiSLang.

You can find those tutorials by going to Help, Expand Tutorials, Under optiSLang, ESD, ESD Workflow, and you can download the materials from here. This is the Air ESD into Calibration Target example. This is an FDTD application that uses nonlinear air chemistry.

Here, you can see the ESD gun geometry. It consists of a ground plane, this solid object that represents some of the geometry of the actual ESD gun, the ESD gun tip, a 2-ohm target, and under curves, we have the connections between the lumped circuit components.

And we have the different components that shape the ESD waveform. Now, let's start by setting up our simulation domain. So, click Domain. Here, I'll expand time, I'll change the stability margin to 30% and the end time to 120 ns.

Now, let's expand lattice, minimum, maximum, and step size, and I'll start by setting the step size to 2 mm in X, Y, and Z. Now, for Minimum X, I'll set it to minus 100 mm, Minimum Y minus 7 mm, and Minimum Z to minus 104 mm. For Maximum X, 112 mm, Maximum Y 92 mm, and Maximum Z 108 mm.

I also changed the divisions to 2 on X, Y, and Z, and this is a total of 8 cores. Now, we can click on the green checkmark, and that's complete, setting up the simulation domain. Now, the next step is to set up our breakdown region where the arc will happen.

So, I'll go and click on breakdown region. We'll be using the Air Chemistry type. Let's go to properties, and I'll change the time to turn on this breakdown region to 20 ns, which is the time for the ESD gun tip to charge up to the appropriate voltage.

Let's set the minimum and maximum values for minimum X minus 6 millimeters, for minimum Y minus 2 millimeters, and for minimum Z minus 6 millimeters, for maximum X 6 millimeters, for maximum Y 4 millimeters, and for maximum Z 6 millimeters.

Now, we can click on the green checkmark, and here's our defined breakdown region. Now, let's hide the breakdown region and the domain. And the next step is to set our voltage source. So, here I'll go and click on thin wire source, and under lumped circuit components, I'll select source.

Let's zoom in, I'll place the source here and name it. Now, we can click on the green checkmark. And now, we need to edit the thin wire radius. Under general, let's change the radius to 0.1 mm. And then click on the green checkmark. Now, we need to add a signal, so let's select this linear ramp.

I'll set the amplitude to 15 kV, and the time to peak to 5 ns. Now, we just need to drag and drop this linear ramp under source, and this completes setting up the source. Now, it's time to assign our materials.

We will assign a perfect conductor to our ESD gun geometry and also the connections between the lumped circuit components. So, here, let's go to materials, select PEC, and here with this select surface, we will go and select the ESD gun geometry.

Let's expand it, and with the select line tool, we can go and select all curves here, and we can go ahead and click the green checkmark. Now, we need to define our circuit components according to this ESD circuit. We have already defined our voltage source.

Now, we need to define the resistors, switches, capacitors, and inductors. So, let's start by defining the switches. I'll click here on switch, and I'll select switch 1, I'll rename it SW1, change the switch type to off, and set the deactivation time to 29 ns.

Let's click on the green checkmark, and let's do the same for the second switch, I call it SW 2. For the other components, we will use the thin wire definition. So, I'll click on thin wire, I'll start by defining the resistors, so here I'll select RS1, RS2, let's call this RS.

Under general, let's change the radius to 0.1 mm, and here, let's add the terminations.

Now, let's expand routing, click on terminations, here with the first termination selected, let's change the resistance to 10 ohms, this one is the other end, let's go to the other termination and set it also to 10 ohms. Then, we can close this and click on the green checkmark.

Now, we can go and define the other circuit components by following the same steps. I have defined all the circuit components according to the ESD circuit. Now, we need to define the target resistance. For this, we will use seams and joints.

So, I start by selecting the target, and then I go to the line selection tool, and I select this line, let's name it rTarget. Let's expand general, and set the resistance to 2 ohms. And now, we can click the green checkmark, and this completes defining the target resistance.

Now, we can go and define our current and voltage probes. I'll start by defining a voltage probe across this charging capacitor. So, I'll select voltage, and here I'll select this is our voltage probe, I'll rename it charging voltage.

Now, let's define a second voltage probe across this gap between the ESD gun tip and the target. I'll select voltage, and I call it gap voltage, and here I'll select these two points. Now, let's define a current probe on the ESD gun.

So, I'll select current, let's name it arcCurrent, the normal direction is Y, and here I'll use the select the body to use option to select the state. So, our current probe will be placed here, we can click on the green checkmark. And now, let's set an animation probe.

So, let's go and select animation, I'll call it animation. For the probe type, I'll select normal electric field, and I'll select this animation plane. Now, let's define a 3D probe to look at the air conductivity.

So, I'll go to Field, select 3D Probe, here I'll set the type to Air Conductivity, I'll call it 3D, and I'll select the target and use the arrows to set up our 3D probe. Now, let's expand time, start, step, and end.

I will set the start time to 20 nanoseconds, for the step, I'll set it to 0.5 ns, and for the end time, I'll set it to 60 ns. Now, we can go and click on the green checkmark, and this is our air conductivity 3D probe.

Now, before meshing the model, we need to set a variable grid to resolve the 2 mm gap between the ESD gun tip and the target. So, here I go and click on Variable Grid, I'll select the target, and I'll use the arrows to set up our variable grid.

And here, I'll change the step size to 0.5 mm for X, Y, and Z. Now, we can click on the green checkmark. Now, we can mesh the model, so let's click mesh, and then click start, and I'll click run to start the simulation. Once the simulation is complete, we can go ahead and view the results.

First, let's plot the charging voltage. As expected, the voltage starts at zero and charges the capacitor up to 15 kV. The arc occurs shortly after 29 ns, and the voltage then drops. Let's also plot the voltage across the gap. This is the arc and voltage.

This voltage goes up, it overshoots the 15 kV, and when the arc occurs, it drops. Now, let's take a look at the arc current. So, here we can see the capacitor charging, and around 29 ns discharging, and this is our expected ESD waveform.

Let's also generate an E-field animation using our animation probe. Here, we can see the E-field building up, and once the arc occurs, the E-field drops. Now, let's take a look at our 3D probe results.

So, I'll go to 3D, click Visualize 3D, here I'll select the last time step and click visualize results. Let's click here to plot the air conductivity, and let's add a cut plane. Here, we need to rotate it 90 degrees around the x-axis, and by moving our cut plane, we can see our arc.

In this video, we went through the Air ESD into Calibration Target tutorial. Thanks for watching, and see you in the next video. Please contact us at https://ozeninc.com/contact for more information.