Inverter Switching Waveform Calculation via Function Formula
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Solution Overview
Problem
Current circuit simulation methods struggle to accurately and efficiently evaluate the influence of switching waveforms on power devices, particularly in large circuits with complex wiring and semiconductor elements, due to limitations in existing models and simulation tools, which often require detailed internal structure information and result in lengthy calculation times.
Innovation Solution
A method is developed to express measured or simulated switching waveforms using a function formula, incorporating an intermediate terminal and a voltage function formula between the upper and lower terminals of an inverter arm, allowing for highly accurate and efficient circuit simulation by fitting the waveform with a low-degree polynomial, enabling wide-ranging circuit calculations with uncertain internal structure information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coupled analysis using device simulation and circuit simulation is performed to accurately evaluate switching waveform influence, then measurement precision is improved, but calculation time increases significantly
Solution Approach 1:
The patent segments the complex coupled analysis into two independent parts: (1) device simulation to obtain switching waveform characteristics, and (2) circuit simulation using extracted equivalent circuit parameters. This segmentation allows each part to be optimized independently, reducing overall calculation time while maintaining accuracy.
Solution Approach 2:
The patent creates an equivalent circuit model that copies the essential electrical characteristics of the semiconductor device without requiring detailed internal structure information. This equivalent model can be used directly in circuit simulation, avoiding the computational burden of detailed device simulation while preserving accuracy for waveform evaluation.
2Measurement precision
If detailed internal structure information of semiconductor devices is used for accurate simulation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential electrical characteristics (such as switching waveform parameters, equivalent circuit parameters) from the complex semiconductor device structure. By taking out only the necessary information for waveform evaluation and discarding unnecessary internal details, the model complexity is reduced while maintaining measurement precision.
Solution Approach 2:
The patent transforms the detailed physical structure parameters of semiconductor devices into electrical equivalent circuit parameters. This parameter transformation simplifies the model by changing from geometric/physical parameters to electrical parameters that directly describe the switching behavior, reducing complexity while preserving accuracy.
3Ease of operation
If standard equivalent circuit models are used for circuit simulation, then ease of operation is improved, but measurement precision deteriorates due to nonlinear internal state changes
Solution Approach 1:
The patent introduces dynamic characteristics into the equivalent circuit model by extracting time-dependent switching waveform parameters from device simulation. The equivalent circuit parameters are not fixed but are updated based on operating conditions (voltage, current, temperature), allowing the model to adapt to nonlinear internal state changes while maintaining ease of circuit simulation.
Data Source
AI summary
In a calculation method of calculating a switching wave form of an inverter by expressing a wave form obtained by measurement or simulation using a function formula, an intermediate terminal is provided between an upper terminal and a lower terminal of an inverter arm and a power supply of a voltage function formula is provided between the upper terminal and the intermediate terminal or the intermediate terminal and the lower terminal. Further, it may be configured such that a variation impact from peripheral circuits at time of switching is calculated and voltage correction calculation is performed to prevent the calculated switching wave form from changing due to the calculation of the variation impact.