Traditional Models vs PLECS Models: Which is Better for Power Electronics Design Simulation?

Latest update time：2024-05-29

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Simulation has become an indispensable basic tool in today's design process, which can verify the selected devices, topologies and other key aspects of the design before the prototype is built. This not only saves time, but also avoids many design risks, making it more likely that the first prototype will achieve the expected performance. In order to achieve the performance and power density required by the latest designs, developers must increase the accuracy as much as possible, so simulation becomes crucial.

Video about the self-service PLECS model generation tool ▼

Challenges in Simulation

The accuracy of a simulation is limited by the accuracy of its underlying model. Even deriving a model from a high-quality data sheet is risky because device characteristic parameters such as conduction loss, energy loss, and thermal impedance are measured under laboratory conditions.

Furthermore, models based on data sheets reflect the manufacturer’s lab configuration and environment, and may not represent the conditions that may be encountered in a real-world implementation. This is especially true for aspects such as parasitic elements that are introduced by the physical layout of the current design (although this may only be part of the reason for the parasitic elements).

Without accurate representation of parasitic elements and any other design-specific properties, the credibility of the simulation is greatly compromised and the results may be inaccurate by up to 30%. For this reason, it is necessary to provide a tool that allows simulation based on specific applications in a defined environment, without having to rely on generic "manufacturer's lab" models.

Driving a Paradigm Shift in Simulation

ON Semiconductor 's PLECS Self-Service Model Generation Tool (SSPMG) achieves the above goals. Designers can enter specific design parasitic information related to the design environment and customize the PLECS model to obtain accurate simulation results.

Figure 1: PLECS Self-Service Model Generation Tool (SSPMG)

The power electronics industry has realized that datasheet-based models are significantly different from reality, and is increasingly aware of the potential benefits of tailoring simulations to individual needs. SSPMG is driving a paradigm shift in the industry with a simulation tool that reflects real-world conditions , significantly improving simulation accuracy and providing you with actionable results. At the core of this tool is a highly accurate, scalable, physically based SPICE model approach.

Figure 2: SSPMG – Industry-leading capabilities

Hard switching and soft switching

The PLECS models used in typical industrial system-level simulation tools are only valid for hard switching and are very inaccurate for soft switching applications. ON Semiconductor’s new PLECS models lead the way and are applicable to both hard and soft switching applications such as DC-DC LLC and CLLC resonant, dual active bridge and phase-shifted full bridge.

The innovative SSPMG simulation tool also allows designers to add custom, data-intensive parameter tables based on electrical bias and temperature conditions. This helps ensure accurate interpolation between data points in the table, virtually eliminating the need for extrapolation, another major source of system simulation error.

Custom application parasitic parameters

Adjustments based on user-specified application circuit parasitics can significantly affect conduction and switching losses.

Data-intensive parameter tables

Adjust conduction loss and switching loss data based on user-specified electrical bias and temperature conditions. Users can create data-dense parameter tables to ensure accurate interpolation and avoid inaccurate extrapolation in system simulations.

Boundary Model

Our boundary models work under typical and boundary conditions of your product, allowing you to track conduction and switching losses under worst, nominal, and best manufacturing conditions, providing further insight into your application’s performance.

Figure 3: SSPMG uses a data-intensive loss parameter table

The requirements of power electronics design must be considered throughout the semiconductor manufacturing process. To this end, the SSPMG tool provides a "boundary model" that represents different manufacturing conditions of electronic products, where parameters such as threshold voltage, RDSon, breakdown voltage, capacitance, etc. are adjusted according to the manufacturing process of the manufacturing plant. It is very important to capture and model the relevant parameter differences at the system level, because these parameter differences will significantly affect the energy loss, conduction loss and temperature behavior.

In power electronics design, designers must distinguish between soft switching and hard switching. For hard switching, the double pulse test (DPT) is a well-known and reliable method for calculating losses. However, soft switching depends on the topology and operating mode, which makes the results generated by DPT inaccurate, so DPT is not applicable to soft switching.

Figure 4: Basic schematic diagram of double pulse tester

To address this problem, SSPMG uses a new conversion loss tester to accurately calculate energy losses. This flexible and comprehensive method is applicable to a range of topologies, including phase-shifted full-bridge (PSFB), DC-DC LLC and CLLC resonant, and can improve the accuracy of soft switching models that have often been overlooked in the past.

Figure 5: ON Semiconductor’s PLECS model generation tool – provides models suitable for simulating soft switching topologies

The good news is that ON Semiconductor's PLECS model is valid for hard switching, soft switching, and synchronous rectification switching.

With SSPMG, designers can use ON Semiconductor power device products to accurately simulate designs and environments with confidence, avoiding the need for drastic redesign of early prototypes later, thereby shortening design cycles.

Designers can drop custom PLECS models generated by SSPMG directly into the simulation environment or upload the models to ON Semiconductor's free Elite Power simulation tool for evaluation. Both tools have recently expanded support to include Field Stop Generation 7 (FS7) IGBT products.

By providing the industry-leading PLECS self-service model generation tool and a broad portfolio of EliteSiC solutions and IGBT products, ON Semiconductor redefines how engineers conceive, design and verify power systems.

Click Read original article Use ON Semiconductor's PLECS model self-service generation tool to experience more accurate simulation and easily generate custom PLECS models.