The simulation of double pulse tests using PCB Spice models is a critical aspect of modern electronics design, particularly in power electronics. This article delves into the intricacies of this process, exploring its significance, methodology, and applications.
Key Takeaways:
- Understanding the importance of double pulse tests in evaluating the performance of power electronics.
- Exploring the role of PCB Spice models in accurately simulating these tests.
- Analyzing the implications of these simulations in the design and optimization of electronic circuits.
Table of Contents
Introduction to Double Pulse Testing
What is Double Pulse Testing?
Double pulse testing is a method used to evaluate the switching performance and robustness of power electronic devices like MOSFETs and IGBTs. This test is crucial for understanding how these devices behave under rapid switching conditions.
In power electronics, the efficiency and reliability of switching devices are paramount. Double pulse testing helps in identifying the switching characteristics, including switching losses, safe operating areas, and thermal performance.
PCB Spice Models in Simulation
Understanding PCB Spice Models
Spice models are a detailed representation of the circuit components and their interactions, making them ideal for simulating complex phenomena like double pulse tests.
Advantages in Simulation
Using PCB Spice models for simulation offers several benefits:
- Accuracy: They can replicate the actual behavior of electronic components under various conditions.
- Flexibility: Allows for easy modification and testing of circuit designs.
- Cost-Effectiveness: Reduces the need for physical prototypes, saving time and resources.
Simulation Process
Setting Up the Simulation
The simulation setup involves creating a circuit design in the Spice model, incorporating the device under test, and configuring the double pulse test parameters. In our case, we will use Ansys Q3D to extract the spice model of the PCB.
Schematic and Layout
For this example, a simple full bridge circuit was chosen, as shown in the schematic below.
Components were arranged on a 4 layer PCB with FR-4 material.
After the layout is finished, EDB file was exported from Altium Designer as shown here: How to Export Ansys EDB File from Altium Designer and imported on Ansys Siwave:
On Ansys Siwave we need to check the stackup, check short-circuit, alignment, vias, solder balls, etc… and export the nets of interest to Q3D:
On Q3D we do the setup of Nets, Sink and Sources, that represent which RLGC we want to simulate, check which materials are being considered, if the 3D model have no issue, do the mesh and run the Setup. After run the setup we can export the spice list of it:
Simulation with SIMETRIX
The Spice Netlist was added to SIMETRIX (https://www.simetrix.co.uk/) with the SPICE model of DC Link capacitors, snubber capacitors and SiC mosfet.
An ideal inductor of 500uH was placed between L1 and L2. SiC Mosfet V2 was keeped ON and SiC Mosfet V3 was chosen to switch and be observed. Dv/dt of the SiC was adjusted with the gate resistor to match similar values expected on the prototype. Dc Link voltage was set to 600vdc and pulse length to match 20Ap during the turn-off.
The result below show Vds without snubber (dashed) and with snubber (solid line), and the continuous Fourier of the pulse. We can see high oscillation on frequency of 34 Mhz also shown on the FFT before adding the snubber.
Green bellow is the Fourier with snubber and red without snubber. High noise is observed after 100Mhz, mainly due to turn on slope that was increase with the snubber capacitors.
Challenges and Solutions
Complex models can be computationally intensive. Optimizing the simulation parameters and using efficient computing resources can mitigate this.
To ensure realistic simulations, it’s crucial to use accurate component models and consider all relevant physical phenomena. It allows designers to predict how a device will perform under various conditions, aiding in making informed design decisions.
Frequently Asked Questions
- What is the purpose of double pulse testing? Double pulse testing is used to evaluate the switching performance of power electronic devices.
- Why are PCB Spice models used for simulation? They offer accurate and flexible means to simulate and analyze electronic circuits.
- Can these simulations replace physical testing? While simulations provide valuable insights, they complement rather than replace physical testing.
Advanced Techniques in Simulation
Incorporating Real-World Variables
Incorporating factors like temperature variations and manufacturing tolerances can enhance the realism of simulations.
Conclusion
In conclusion, the simulation of double pulse tests using PCB Spice models is a vital tool in the arsenal of electronics designers. It offers a blend of accuracy, efficiency, and cost-effectiveness, making it indispensable in the realm of power electronics.
If you have any question or this type of need, please send a message on Contact.
admin