초록 ▼

A remaining charge detecting system of an electric double layer capacitor to be usable, for example, as an energy source of a hybrid vehicle having an internal combustion engine and an electric motor separately driving wheels. The system includes a current-voltage sensor which generates an output in

A remaining charge detecting system of an electric double layer capacitor to be usable, for example, as an energy source of a hybrid vehicle having an internal combustion engine and an electric motor separately driving wheels. The system includes a current-voltage sensor which generates an output indicative of a terminal voltage across terminals of the capacitor and an output indicative of charge/discharge current charged into and discharged from the capacitor and an electronic control unit, comprising a microcomputer, which inputs the outputs of the current-voltage sensor indicative of the terminal voltage and charge/discharge current and calculates a remaining charge of the capacitor based on a state equation (mathematical model) having the remaining charge of the capacitor as a state variable and an observer that observes the state equation, thereby enabling simple and accurate detection of the remaining charge of the electrical double layer capacitor without need for a high-precision current sensor.

대표청구항 ▼

A remaining charge detecting system of an electric double layer capacitor to be usable, for example, as an energy source of a hybrid vehicle having an internal combustion engine and an electric motor separately driving wheels. The system includes a current-voltage sensor which generates an output in

A remaining charge detecting system of an electric double layer capacitor to be usable, for example, as an energy source of a hybrid vehicle having an internal combustion engine and an electric motor separately driving wheels. The system includes a current-voltage sensor which generates an output indicative of a terminal voltage across terminals of the capacitor and an output indicative of charge/discharge current charged into and discharged from the capacitor and an electronic control unit, comprising a microcomputer, which inputs the outputs of the current-voltage sensor indicative of the terminal voltage and charge/discharge current and calculates a remaining charge of the capacitor based on a state equation (mathematical model) having the remaining charge of the capacitor as a state variable and an observer that observes the state equation, thereby enabling simple and accurate detection of the remaining charge of the electrical double layer capacitor without need for a high-precision current sensor. id subterranean formation. 3. The method of claim 2, wherein the waveform element is a single cycle of a 60 Hz sinusoid. 4. The method of claim 2, wherein the waveform element is constructed from selected phases of a three-phase power supply to have a desired frequency less than or equal to 60 Hz. 5. The method of claim 2, wherein said digital code is a maximal length shift-register {1,-1} sequence with the resulting source waveform modified to a {1,0} sequence by zeroing the negative polarity elements; said reference waveform is the square of the source waveform before the negative polarity elements are zeroed, said squared wave then undergoing polarity reversal of segments corresponding to "-1" terms in said maximal length shift-register sequence; and said correlation is circular correlation. 6. The method of claim 5, wherein said interference reduction is accomplished by constructing a second source waveform by reversing the polarity of the source waveform selected in step (a), repeating steps (b)-(d) with said second source waveform, and then adding together the correlated seismic signals resulting from the two source waveforms. 7. The method of claim 5, wherein said interference reduction is accomplished by replacing some pre-selected "1" terms in said {1,0} source wave coding sequence with "1" terms, said replacement being designed to substantially maximize the time separation between said correlation of the source waveform and said correlation of the square of the source waveform. 8. The method of claim 7, wherein which "1" terms to replace with -1 are determined by multiplying said {1,0} sequence by a circularly rotated version of said maximal length shift-register {1,-1} sequence, thereby generating the desired {1,-1,0} code. 9. The method of claim 5, wherein the degree of said maximal length shift-register sequence is sufficiently large to reduce said side lobe amplitudes to a predetermined level. 10. The method of claim 5, wherein said transmitting of said source waveform into said subterranean formation is repeated a sufficient number of times to reduce loss of information due to said circular correlation to a predetermined level. 11. The method of claim 7, wherein said interference reduction is further accomplished by constructing a second source waveform by reversing the polarity of the source waveform selected in step (a), repeating steps (b)-(d) with said second source waveform, and then adding together the correlated seismic signals resulting from the two source waveforms. 12. The method of claim 1, wherein said reference waveform is bandpass filtered to conform to the expected frequency content of said recorded seismic signals. 13. The method of claim 1, further comprising the following additional step: (e) ordering the seismic signals from the subterranean formation by amplitude, and interpreting any substantially larger amplitudes to represent hydrocarbons. 14. A method for electroseismic prospecting of a subterranean formation, said method comprising the steps of: (a) selecting a periodic waveform; (b) generating said waveform as an electrical signal and transmitting it into said subterranean formation at a preselected frequency; (c) detecting and recording seismic signals resulting from conversion of the electrical energy into seismic energy in said subterranean formation; (d) Fourier transforming said seismic signals from the time domain to the frequency domain; (e) collecting the transformed data at twice the signal frequency, and extracting amplitude and phase information; (f) repeating steps (b)-(e) for a plurality of different signal frequencies; and (g) inverse Fourier transforming the extracted amplitude and phase information of step (e) back to the time domain. 15. An electrical signal for use in electroseismic prospecting of a subterranean formation, said signal having a waveform constructed from a single element, said element consisting of a single full cycle of a preselected per