Engineering topics
Publications and source records attributed to Morrison, John L..
Impedance testing devices, circuits, systems, and related methods are disclosed. A method may include exciting a device coupled to a load, and capturing a response of the device. The method may further include adjusting the response based on an estimated load response of the device, and estimating an impedance of the device based on the adjusted response.
Impedance testing devices, circuits, systems, and related methods are disclosed. A Device Under Test (DUT) is excited with a multispectral excitation signal for an excitation time period while the DUT is under a load condition from a load operably coupled to the DUT. A response of the DUT is sampled over a sample time period. The sample time period is configured such that it includes an in-band interval during the excitation time period and one or more out-of-band intervals outside of the in-band interval. A response of the DUT to the load condition during the in-band interval is estimated by analyzing samples of the response from the one or more out-of-band intervals. Adjusted samples are computed by subtracting the estimated load response during the in-band interval from the samples from the in-band interval. An impedance of the DUT is estimated by analyzing the adjusted samples.
Real-time battery impedance spectra are acquired by stimulating a battery or battery system with a signal generated as a sum of sine signals at related frequencies. An impedance measurement device can be used to interface between the battery system and a host computer for generating the signals. The impedance measurement device may be calibrated to adapt the response signal to more closely match other impedance measurement techniques. The impedance measurement device may be adapted to operate at mid-range voltages of about 50 volts and high-range voltages up to about 300 volts.
Real-time battery impedance spectra are acquired by stimulating a battery or battery system with a signal generated as a sum of sine signals at related frequencies. An impedance measurement device can be used to interface between the battery system and a host computer for generating the signals. The impedance measurement device may be calibrated to adapt the response signal to more closely match other impedance measurement techniques. The impedance measurement device may be adapted to operate at mid-range voltages of about 50 volts and high-range voltages up to about 300 volts.
Battery impedance testing devices, circuits, systems, and related methods are disclosed. An impedance measurement device includes a current driver configured to generate an excitation current signal to be applied to a test battery responsive to a control signal, and a processor operably coupled with the current driver. The processor is configured to generate the control signal during an auto-ranging mode and a measuring mode. The auto-ranging mode applies the excitation current signal to the test battery over a plurality of different amplitudes to measure a response to the excitation current signal at each amplitude. The measuring mode applies the excitation current signal to the test battery for an amplitude responsive to the results of the auto-ranging mode. Improved sensitivity and resolution may be achieved for low impedance batteries with a rapid measurement time.
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Energy storage cell impedance testing devices, circuits, and related methods are disclosed. An energy storage cell impedance measuring device includes a sum of sinusoids (SOS) current excitation circuit including differential current sources configured to isolate a ground terminal of the differential current sources from a positive terminal and a negative terminal of an energy storage cell. A method includes applying an SOS signal comprising a sum of sinusoidal current signals to the energy storage cell with the SOS current excitation circuit, each of the sinusoidal current signals oscillating at a different one of a plurality of different frequencies. The method also includes measuring an electrical signal at a positive terminal and a negative terminal of the energy storage cell, and computing an impedance of the energy storage cell at each of the plurality of different frequencies using the measured electrical signal.
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Real-time battery impedance spectrum is acquired using a one-time record. Fast Summation Transformation (FST) is a parallel method of acquiring a real-time battery impedance spectrum using a one-time record that enables battery diagnostics. An excitation current to a battery is a sum of equal amplitude sine waves of frequencies that are octave harmonics spread over a range of interest. A sample frequency is also octave and harmonically related to all frequencies in the sum. A time profile of this sampled signal has a duration that is a few periods of the lowest frequency. A voltage response of the battery, average deleted, is an impedance of the battery in a time domain. Since the excitation frequencies are known and octave and harmonically related, a simple algorithm, FST, processes the time profile by rectifying relative to sine and cosine of each frequency. Another algorithm yields real and imaginary components for each frequency.
Real-time battery impedance spectrum is acquired using a one-time record. Fast Summation Transformation (FST) is a parallel method of acquiring a real-time battery impedance spectrum using a one-time record that enables battery diagnostics. An excitation current to a battery is a sum of equal amplitude sine waves of frequencies that are octave harmonics spread over a range of interest. A sample frequency is also octave and harmonically related to all frequencies in the sum. The time profile of this signal has a duration that is a few periods of the lowest frequency. The voltage response of the battery, average deleted, is the impedance of the battery in the time domain. Since the excitation frequencies are known and octave and harmonically related, a simple algorithm, FST, processes the time record by rectifying relative to the sine and cosine of each frequency. Another algorithm yields real and imaginary components for each frequency.
Real time battery impedance spectrum is acquired using one time record, Compensated Synchronous Detection (CSD). This parallel method enables battery diagnostics. The excitation current to a test battery is a sum of equal amplitude sin waves of a few frequencies spread over range of interest. The time profile of this signal has duration that is a few periods of the lowest frequency. The voltage response of the battery, average deleted, is the impedance of the battery in the time domain. Since the excitation frequencies are known, synchronous detection processes the time record and each component, both magnitude and phase, is obtained. For compensation, the components, except the one of interest, are reassembled in the time domain. The resulting signal is subtracted from the original signal and the component of interest is synchronously detected. This process is repeated for each component.