Method and apparatus to determine battery resonance
A system and method to determine a resonant frequency of a battery is presented. One embodiment of the invention utilizes a PLL, digital or analog, to adjust the phase angle of a modulated current charging signal to that of the resonant frequency of the battery. A second embodiment of the invention utilizes an energy managed delta function to determine the resonant frequency of the battery. A third embodiment utilizes a small signal frequency sweep in order to determine the resonant frequency of the battery.
1 . A system for determining a resonant frequency of the battery, comprising:
a power supply adapted to provide a power signal;
a current driver/generator system adapted to receive a power signal and generate a current charging signal;
a current/voltage monitoring system adapted to receive current and battery temperature signals, and generate a current monitoring signal and a battery temperature signal;
a current charging signal processing system adapted to receive the current monitoring signal and a battery temperature signal and provide a control signal to the current driver/generator system, and modulate the current charging signal with a waveform; and
a load, adapted to receive the modulated current charging signal.
2 . The system of claim 1 , wherein the current and battery signals are generated by sensors.
3 . The system of claim 1 , wherein the current and battery signals are converted to digital with Analog to Digital converters.
4 . The system of claim 1 , wherein the current charging signal processing system performs a Fast Fourier Transform (FFT).
5 . The system of claim 1 , wherein the current charging signal processing system supplies a charge cut-off signal to the current driver/generator system.
6 . A method for applying a current step function at the beginning of consecutive intervals during the over-all charging cycle, comprising:
applying a specific frequency and charging waveform to a battery;
calculate the resonant frequency of the battery;
applying the calculated resonant frequency over one resonant charging interval; and
repeating the aforementioned steps.
7 . The method of claim 6 , wherein the resonant charging interval is two minutes.
8 . A method for determining a resonant frequency of the battery using a phase-locked loop, comprising:
generating a current charging signal;
sampling a battery voltage;
modulating current charging signal to match battery resonant frequency;
determining a phase angle of the battery voltage sample and the modulated current charging signal;
determining whether there is a phase error between the modulated current charging signal and the battery voltage sample;
adjusting the modulated current charging signal frequency to eliminate the phase angle error; and
idling until a next battery voltage sampling.
9 . The method of claim 8 , wherein the battery voltage is sampled with a sensor.
10 . The method of claim 8 , wherein the current charging signal is modulated by a microprocessor.
11 . The method of claim 8 , wherein the phase angle of the battery voltage sample and the modulated current charging signal is calculated with a microprocessor.
12 . The method of claim 8 , wherein the modulated current charging signal frequency is adjusted by a microprocessor.
13 . A method for determining the resonant frequency of the battery using a “managed” delta function, comprising:
sending a managed delta function to a battery;
sampling a battery voltage;
generating gain and phase data from the battery voltage sample;
analyzing the gain and phase data to find voltage peaks for different frequencies;
determining the resonant frequency of the battery by selecting the frequency with the highest voltage peak; and
modulating the current charging signal at the resonant frequency of the battery.
14 . The method of claim 13 , wherein the managed delta function is a delta function that is clipped to avoid saturation of the battery.
15 . The method of claim 13 , wherein the battery voltage is sampled with a sensor.
16 . The method of claim 13 , wherein the gain and phase data from the battery voltage sample is generated with a microprocessor.
17 . A method for determining the resonant frequency of the battery by frequency sweeping, comprising:
receiving a predefined battery frequency range;
initializing a sweep frequency to a lowest frequency in the battery frequency range;
incrementing the sweep frequency by 1.0 Hz until the entire battery frequency range is covered;
sampling the battery voltage;
comparing frequencies having voltage peaks to determine the highest voltage peak;
determining the highest voltage peak frequency;
processing the highest voltage peak frequency signal to obtain greater resonant frequency resolution;
comparing frequencies having voltage peaks to determine the battery resonant frequency with a greater resolution; and
modulating current charging signal with the frequency associated with the highest voltage peak.
18 . The method of claim 17 , wherein the highest voltage peak frequency signal is processed by dithering.
19 . The method of claim 18 , wherein the highest voltage peak frequency signal is dithered by a microprocessor.
20 . The method of claim 17 , wherein the predefined battery frequency range is from 100 Hz to 120 Hz.
21 . The method of claim 17 , wherein battery voltage is sampled with a sensor.
22 . The method of claim 17 , wherein the current charging signal is modulated with a microprocessor.
23 . The method of claim 17 , wherein the frequencies having voltage peaks are calculated with a microprocessor.
24 . The method of claim 17 , wherein the highest voltage peak frequency is calculated with a microprocessor.
25 . The method of claim 17 , wherein the highest voltage peak frequency signal is processed by re-sweeping the highest peak frequency 10 Hz band in increments of 0.1 Hz.