Battery state of charge detection
First Claim
1. A battery state of charge detection device for use with an electric circuit that drives a motor by using a current supplied from a battery, the electric circuit comprising an inverter that controls operation of the motor and a controller that outputs a motor control signal to the inverter to supply from the battery to the motor a current corresponding to a requested output to the motor, the battery having a rated discharge range relating to a discharge current, the battery state of charge detection device comprising:
- a first current sensor that detects a discharge current of the battery, the first current sensor having a measurable current range that slightly exceeds an upper limit value of the rated discharge range; and
a microprocessor programmed to;
determine whether or not the current detected by the first current sensor exceeds the upper limit value;
compute a state of charge of the battery based on the motor control signal when the current detected by the first current sensor exceeds the upper limit value; and
compute the state of charge of the battery based on a current value detected by the first current sensor when the current detected by the first current sensor does not exceed the upper limit value.
1 Assignment
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Accused Products
Abstract
A state of charge of a battery (1) that drives a motor (6) is computed based on a discharge current measured by a current sensor (3) when the discharge current of the battery (1) does not exceed a rated discharge range of the battery (1). When the discharge current of the battery (1) exceeds the rated discharge range, the state of charge of the battery (1) is computed by estimating the discharge current of the battery (1) from a motor control signal, whereby current changes over a wide range can be found with good precision using the sensor (3), which has a narrow but high resolution measurable range, and the state of charge can be accurately detected.
21 Citations
7 Claims
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1. A battery state of charge detection device for use with an electric circuit that drives a motor by using a current supplied from a battery, the electric circuit comprising an inverter that controls operation of the motor and a controller that outputs a motor control signal to the inverter to supply from the battery to the motor a current corresponding to a requested output to the motor, the battery having a rated discharge range relating to a discharge current, the battery state of charge detection device comprising:
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a first current sensor that detects a discharge current of the battery, the first current sensor having a measurable current range that slightly exceeds an upper limit value of the rated discharge range; and a microprocessor programmed to; determine whether or not the current detected by the first current sensor exceeds the upper limit value; compute a state of charge of the battery based on the motor control signal when the current detected by the first current sensor exceeds the upper limit value; and compute the state of charge of the battery based on a current value detected by the first current sensor when the current detected by the first current sensor does not exceed the upper limit value. - View Dependent Claims (2, 3, 4, 5)
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6. A battery state of charge detection device for use with an electric circuit that drives a motor by using a current supplied from a battery, the electric circuit comprising an inverter that controls operation of the motor and a controller that outputs a motor control signal to the inverter to supply from the battery to the motor a current corresponding to a requested output to the motor, the battery having a rated discharge range relating to a discharge current, the battery state of charge detection device comprising:
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means for detecting a discharge current of the battery, the discharge current detecting means having a measurable current range that slightly exceeds an upper limit value of the rated discharge range; and means for determining whether or not the current detected by the discharge current detecting means exceeds the upper limit value; means for computing a state of charge of the battery based on the motor control signal when the current detected by the discharge current detecting means exceeds the upper limit value; and means for computing the state of charge of the battery based on a current value detected by the discharge current detecting means when the current detected by the discharge current detecting means does not exceed the upper limit value.
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7. A battery state of charge detection method using an electric circuit that drives a motor by using a current supplied from a battery, the electric circuit comprising an inverter that controls operation of the motor and a controller that outputs a motor control signal to the inverter to supply from the battery to the motor a current corresponding to a requested output to the motor, the battery having a rated discharge range relating to a discharge current, the battery state charge detection method comprising:
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detecting a discharge current of the battery by using a current sensor having a measurable current range that slightly exceeds an upper limit value of the rated discharge range; determining whether or not the current detected by the current sensor exceeds the upper limit value; computing a state of charge of the battery based on the motor control signal when the current detected by the current sensor exceeds the upper limit value; and computing the state of charge of the battery based on a current value detected by the current sensor when the current detected by the current sensor does not exceed the upper limit value.
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Specification