Inductance Estimation in Power Converters
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Solution Overview
Problem
Conventional power converters face challenges in accurately measuring output current due to inaccuracies in inductance estimation, which varies with temperature and fabrication inaccuracies, leading to errors in power supply control.
Innovation Solution
An estimator determines the inductance of the inductor using current sense signals, allowing for more accurate estimation of output current without requiring pre-programmed inductance values, and can be implemented in hardware or software, enabling precise control of power converters during full power supply operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pre-programmed inductance values are used for current estimation, then device complexity is reduced, but measurement precision deteriorates due to temperature variations and fabrication inaccuracies
Solution Approach 1:
The system uses the power converter's own operational signals (voltage and current waveforms) to automatically determine the inductance value, eliminating the need for external programming or separate measurement devices. The converter self-calibrates by analyzing its own switching behavior during normal operation.
Solution Approach 2:
The system continuously monitors the relationship between voltage applied to the inductor and the resulting current change, using this feedback to calculate and update the inductance value. This closed-loop approach compensates for temperature drift and fabrication variations in real-time.
2Productivity
If inductance values are determined during full power supply operation, then productivity is improved by eliminating test modes, but measurement precision may be affected by operational variations
Solution Approach 1:
The system performs inductance determination during brief intervals within the normal switching cycle, using the predictable timing of switch transitions to capture accurate measurements without requiring separate test modes. The measurement window is pre-established based on the switching waveform characteristics.
Solution Approach 2:
The system adapts the measurement approach based on the dynamic operating conditions, selecting appropriate time windows within the switching cycle where the inductor behavior is most predictable. The measurement process dynamically adjusts to different load and voltage conditions while maintaining accuracy.
Data Source
AI summary
An apparatus includes a power converter and an estimator. The power converter produces an output voltage to power a load via current through an inductor. The estimator receives a current sense signal from a current monitor resource. The current sense signal represents/indicates a measured magnitude of the current supplied to the load through the inductor over time during one or more power delivery control cycles. Portions of the current sense signal may be an inaccurate representation of an amount of current through the inductor. Via the current sense signal, or portion thereof, the estimator determines (such as calculates) an inductance (value) of the inductor. The estimator then uses the calculated inductance value to estimate a magnitude of the output current supplied through the inductor to the load.