DUT Measurement Circuit With Synchronous Sampling for Harmonic Minimization
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Solution Overview
Problem
Existing battery management systems face challenges in accurately determining battery impedance due to harmonics and aliasing issues during voltage and current measurement, which affect the signal-to-noise ratio and subsequently the accuracy of battery management operations.
Innovation Solution
A measurement circuit that generates an excitation signal at a target frequency and adjusts sampling control parameters to minimize harmonics, using a combination of clock circuits, driver circuits, and analog-to-digital converters to optimize the sampling frequency and digitization of sense signals, thereby improving the signal-to-noise ratio and accuracy of impedance estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sampling operations are performed to obtain voltage and current measurements, then measurement data is acquired for battery management, but harmonics and aliasing are introduced that reduce signal-to-noise ratio and measurement accuracy
Solution Approach 1:
The patent applies periodic action by using synchronous sampling where the sampling frequency is an integer multiple of the excitation signal frequency. This periodic relationship between sampling and excitation signals allows harmonics to be systematically positioned in the frequency spectrum, enabling their identification and minimization while maintaining accurate measurement of the fundamental frequency components.
Solution Approach 2:
The patent changes the sampling frequency parameter to be an integer multiple of the excitation signal frequency. This parameter adjustment ensures that harmonics fall at specific frequency intervals, allowing the system to optimize the sampling rate to minimize harmonic interference while maintaining measurement accuracy for battery impedance determination.
2Measurement precision
If excitation signal is applied at target frequency to determine battery impedance, then impedance measurement is enabled, but harmonics are generated that affect signal-to-noise ratio
Solution Approach 1:
The patent implements feedback by using the known relationship between excitation signal frequency and sampling frequency to predict and identify harmonic positions in the frequency spectrum. This feedback mechanism allows the system to adjust sampling parameters to minimize harmonics at the target frequency, thereby improving signal-to-noise ratio and impedance measurement accuracy.
3Productivity
If ADC digitizes sense signals at fixed frequency, then signal conversion is performed, but aliasing occurs that reduces accuracy of obtained samples
Solution Approach 1:
The patent applies dynamics by making the ADC sampling frequency adaptive rather than fixed. The sampling frequency is dynamically adjusted to be an integer multiple of the excitation signal frequency, allowing the system to maintain high conversion rates while preventing aliasing through proper frequency relationship management between sampling and signal sources.
Data Source
AI summary
A circuit comprises a driver circuit, a processing circuit, and a control circuit. The driver circuit has a first frequency control input and a driver output. The processing circuit has a sense input, a second frequency control input, and a parameter output. And the control circuit has a first frequency control output and a second frequency control output, the first frequency control output coupled to the first frequency control input, and the second frequency control output coupled to the second frequency control input.