Control system for, in the presence of a varying system load, establishing generator current to maintain a particular battery charge state
First Claim
1. A method for controlling the state of charge of a battery of a hybrid electric vehicle around a set state of charge which is less than full charge, by controlling an electrical power generator, said method comprising the steps of:
- estimating the state of charge of said battery to generate signals representative of the existing state of charge of said battery;
generating signals representative of the desired state of charge of said battery;
taking the difference between said signals representative of the existing (present) state of charge and said signals representative of the desired state of charge to generate state-of-charge error signals;
processing said state-of-charge error signals by at least integrating, to produce desired generator current signals;
sensing the generator current to produce existing generator current signals;
taking the difference between said existing generator current signals and said desired generator current signals to produce generator-current error signals;
processing said generator-current error signals by at least integration to produce a generator output current command; and
controlling the electrical current output of said generator in response to said generator output current command.
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Accused Products
Abstract
A controller for a hybrid electric system such as a hybrid electric vehicle includes a load, a battery, and a controllable source of auxiliary electricity. The state of charge (SOC) of the battery is estimated, and an error signal is generated which represents the difference between a desired and actual SOC. The SOC error signal is processed by at least integration, to produce a source signal representing the desired auxiliary source current. A second error signal is generated between the actual current. from the auxiliary source and the desired current from the auxiliary source. The second error signal is processed, at least by integration, to produce a control signal for controlling the auxiliary signal source.
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Citations
17 Claims
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1. A method for controlling the state of charge of a battery of a hybrid electric vehicle around a set state of charge which is less than full charge, by controlling an electrical power generator, said method comprising the steps of:
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estimating the state of charge of said battery to generate signals representative of the existing state of charge of said battery; generating signals representative of the desired state of charge of said battery; taking the difference between said signals representative of the existing (present) state of charge and said signals representative of the desired state of charge to generate state-of-charge error signals; processing said state-of-charge error signals by at least integrating, to produce desired generator current signals; sensing the generator current to produce existing generator current signals; taking the difference between said existing generator current signals and said desired generator current signals to produce generator-current error signals; processing said generator-current error signals by at least integration to produce a generator output current command; and controlling the electrical current output of said generator in response to said generator output current command. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for controlling the impedance of a battery of a hybrid electric vehicle around a set impedance by controlling an electrical power generator, said method comprising the steps of:
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estimating the impedance of said battery to generate signals representative of the existing impedance of said battery; generating signals representative of the desired impedance of said battery; taking the difference between said signals representative of the existing impedance and said signals representative of the desired impedance to generate impedance error signals; processing said impedance error signals by at least integrating, to produce desired generator current signals; sensing the generator current to produce existing generator current signals; taking the difference between said existing generator current signals and said desired generator current signals to produce generator-current error signals; processing said generator-current error signals by at least integration to produce a generator speed command; and controlling the electrical current output of said generator in response to said generator speed command. - View Dependent Claims (12)
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13. An apparatus for controlling the charge state of a battery associated with a controllable auxiliary source of electrical power and a load, said apparatus comprising:
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a state-of-charge estimator associated with said battery; a load; a load current sensor coupled to said load; a controllable electrical source; a source current sensor coupled to said controllable electrical source, for generating source current signals representing the current generated by said controllable electrical source; power conveying means coupled to said battery, said load, and to said controllable electrical source, for allowing power to flow among said load, said battery, and said electrical source; a source of signals representing a desired state of battery charge; a first error signal generator coupled to said state-of-charge estimator and to said source of signal representing a desired state of battery charge, for taking the difference therebetween, for generating state-of-charge error signals; first processing means coupled to said first error signal generator, for processing said state-of-charge error signals by at least integrating said state-of-charge error signals, to thereby produce desired-source-current signals representing the current to be produced by said controllable electrical source; second error signal generating means coupled to said first processing means and to said source current sensor, for taking the difference between said desired-source-current signals and said source current signals, to thereby generate source current error signals; second processing means coupled to said second error signal generating means, for processing said source current error signals by at least integration, to thereby produce controllable electrical source control signals; and coupling means coupled to said second processing means and to said controllable electrical source, for coupling said controllable electrical source control signals to said controllable electrical source for controlling said controllable electrical source. - View Dependent Claims (14, 15, 16, 17)
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Specification