Real-time AC-impedance inspection using limited-energy on-board AC excitation for battery management system
US11644513B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 7, 2022 |
| Grant date | May 9, 2023 |
| Priority date | — |
| Expiry date | Jan 7, 2042 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A Battery Management System (BMS) inspects a battery pack using AC impedance. A controller on the BMS drives a Pulse-Width Modulation (PWM) output signal to an on-board excitation regulator such as a synchronous buck converter that modulates a limited energy unit such as a capacitor with a swept frequency of a PWM input signal. The capacitor modulations are applied to a terminal of the battery pack as an AC excitation signal. Synchronous sampling of the battery pack provides responses to the AC excitation signal. An AC excitation signal current and a battery response voltage are processed and Fourier-transformed to generate a Nyquist plot of the excitation-response data. Curve shifts can indicate worn battery cells. The capacitor generating the AC excitation signal draws little energy from the battery pack so AC impedance inspection can occur during all modes: charging, discharging, and idle modes without an external power supply.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.