Inductor Value Determination in Power Converters
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Solution Overview
Problem
Existing methods for determining the inductor value of a power converter require significant analog signal processing infrastructure, which is not compatible with industrial applications.
Innovation Solution
A method that uses an inductor value measurement circuit to determine the inductor value based on the output voltage and reference peak inductor current, independent of the input voltage, by establishing a relationship between these parameters through a controller's inner loop, allowing for accurate determination without perturbing the circuit or output voltage during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If model observer or signal injection methods are used to determine inductor value, then measurement precision is improved, but device complexity increases due to required analog signal processing infrastructure
Solution Approach 1:
The patent extracts the inductor value determination function from complex analog signal processing infrastructure and implements it using simple digital processing of readily available voltage and current signals. The inductor value is calculated by extracting the fundamental frequency component of the voltage signal and comparing it with the known inductor current, eliminating the need for dedicated analog measurement circuits.
Solution Approach 2:
The patent replaces analog signal processing mechanisms with digital signal processing. Instead of using analog filters, oscillators, and signal injection circuits, the invention uses digital algorithms to process voltage and current signals, perform Fourier analysis, and calculate inductor value, thereby simplifying the hardware infrastructure.
2Measurement precision
If expensive current sensors or fast analog-to-digital converters are used, then measurement precision is improved, but loss of energy increases and device complexity increases
Solution Approach 1:
The patent makes the existing voltage and current signals in the power converter serve a dual purpose: controlling the converter operation and providing data for inductor value determination. The voltage signal already present in the system is used for both switching control and for calculating the inductor value through fundamental frequency analysis, eliminating the need for separate measurement circuits and reducing energy consumption.
Solution Approach 2:
Instead of using expensive fast ADCs or high-precision current sensors, the patent creates a simplified digital representation of the voltage signal by extracting its fundamental frequency component. This copied signal is sufficient for inductor value calculation and can be processed using lower-speed, lower-cost digital converters.
3Measurement precision
If inductor value determination perturbs the circuit or output voltage, then measurement precision might be improved, but stability of the object's composition deteriorates
Solution Approach 1:
The patent performs inductor value determination during the startup phase or in steady-state conditions using existing operating signals, before any perturbation would affect normal operation. By utilizing voltage and current signals that are already present during normal converter operation, the method determines inductor value without introducing additional disturbances to the circuit.
Solution Approach 2:
The patent uses the existing feedback control signals in the power converter (voltage and current signals used for regulation) to determine the inductor value. These signals are already being processed by the control system, so utilizing them for parameter identification does not require additional perturbations or disrupt the feedback loop stability.
Data Source
AI summary
A circuit having a power converter configured to convert an input voltage to an output voltage; a controller having an inner loop configured to regulate a peak inductor current of an inductor of the power converter to a reference peak inductor current value; and an inductor value measurement circuit configured to determine a value of the inductor based on the output voltage of the power converter and the reference peak inductor current value.