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Extracting Small Signal Models of Power Converters Using Time Domain Step Response Simulation in SPICE
  • Denys Zaikin
Denys Zaikin

Corresponding Author:[email protected]

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This document presents a simple method that allows the use of time-domain simulation to extract an AC small signal model of the power stage of a power converter. Such extraction can be important for the simulation of feedback loop gain and the stability of complex power converter topologies, such as resonant converters or converters with complex switch control. With the presented approach, a single simulation run in the time domain is sufficient to extract a small signal model, resulting in a time-efficient extraction process. The method is based on the step response simulation, where the input control signal source (duty cycle, switching frequency, etc.) is applied as a step function. The output parameter of the converter (output voltage, current, etc.) is recorded during the time-domain simulation and then transformed into a SPICE netlist using Laplace transform statements. The Laplace transform in s-domain is supported by most SPICE simulators, such as LTspice, PSpice, etc. The presented algorithm and model are automatically generated using a developed open-source software tool. Thus, the free software LTspice, along with the presented open-source tool, can be used as a free alternative to commercial SPICE programs like PSpice, PADS, Simetrix, MATLAB, etc.
27 May 2024Submitted to TechRxiv
03 Jun 2024Published in TechRxiv