Power Electronics Simulation Assessment: Three Standards Beyond Just "Pretty Waveforms"

Summary: It is common in power electronics projects for simulations to look perfect, only for the physical board to fail. The root cause usually lies in a lack of result credibility, insufficient scenario coverage, and prohibitive model migration costs—all of which undermine engineering judgment. This article explores the criteria for evaluating simulation tools to mitigate these risks.

Many board redesigns begin with the phrase: "It should pass this time."

The problem with this mindset is that the failure isn't as immediate as a software crash. The results exist, the graphs look professional, and the parameters appear to be within range. The project moves forward, but the team remains uneasy. Later, when the board is tested and margins are found to be insufficient, the team is forced to re-converge parameters, disrupting the entire validation flow.

Redesigns, supplementary testing, and re-convergence often start from this state of "technically not wrong, but not confident enough to sign off." To avoid this, engineering teams must shift from evaluating tools based on "pretty waveforms" to assessing them against three rigorous standards.

Standard I: Result Credibility

Power electronics simulation must do more than display waveforms; it must support actionable engineering decisions regarding losses, margins, stability, and system risks. Engineers need stable, reliable answers to critical questions:

• Accuracy: Can we trust the calculated switching and conduction losses?

• Stress: Are device voltage and current stresses within limits?

• Signal Integrity: Will $V_{ds}$ and $V_{gs}$ overshoot or ringing trigger failures?

• Magnetics: Is the core near saturation, and is the loss estimation realistic?

• Stability: Are the loop stability and phase margins sufficient?

• Thermal/Noise: Are the transient temperature trends and EMI risks accurately exposed?

In power electronics, credibility is measured by whether the simulation acts as a design basis rather than a mere visual reference. If the team’s confidence level remains "should be fine," the tool is not yet ready for final design sign-off.

Standard II: Scenario Coverage

Often, teams know exactly what needs to be verified, but the computational cost of doing so is too high. When system complexity increases and simulation speed drops, teams are forced to "cut corners":

• Sweeping fewer parameters.

• Reducing the number of corners.

• Simplifying models.

• Ignoring parasitics or skipping critical operational scenarios.

These shortcuts turn a simulation from a decision-making tool into a reference document. Speed is not just a productivity metric—it directly determines whether the team has the courage to run all the necessary scenarios.

Standard III: Model Migration Costs

Teams rarely suffer from a lack of models; they suffer from the inability to use them. Upstream vendors provide high-precision models, and teams possess their own historical libraries. However, engineers often face:

• Syntax Incompatibility: Models written for Tool A are unreadable in Tool B.

• Encryption: Encrypted vendor models cannot be imported or converted.

• Integration Risk: High migration costs for historical assets, even when conversion is possible.

When evaluating a new tool, the first question is always: "What do I do with my current pile of models?" If the barrier to entry is rebuilding years of R&D assets, the discussion regarding precision and speed never truly begins.

The Core Assessment Criteria

As a project progresses, these three factors are inextricably linked: higher precision requirements increase computational pressure; slower speeds lead to forced simplifications; and forced simplifications undermine decision-making.

To break this cycle, power electronics teams should evaluate simulation tools based on three "gatekeeper" questions:

• Credibility: Can the team confidently make final design decisions based on the results?

• Coverage: When the system gets large, will the team still be able to run all required scenarios without skipping them due to speed?

• Compatibility: Can existing internal and vendor models be integrated without starting from scratch?

A New Class of Tools

PowerExpert is a high-precision mixed-signal simulation platform designed specifically for power electronics systems. It addresses these requirements by integrating mixed-mode behaviors (control loops and non-linear power devices), supporting full-scenario validation (LLC, BUCK topologies), and facilitating the seamless integration of devices, magnetics, behavioral models, and control algorithms. It unifies DC, AC, transient, noise, parasitic, electromagnetic, and thermal effects into a single workflow.

Ultimately, your assessment comes down to three judgments:

• Can we sign off on critical operating conditions?

• Will scenarios be deleted just because the simulation is too slow?

• Will migration costs deadlock the transition to a better tool?

In the next article, we will discuss how PowerExpert specifically addresses these three standards.