Multi-battery pack for power tools
First Claim
Patent Images
1. A power tool comprising:
- a motor;
a first battery pack;
a second battery pack;
a first switching element coupled between the first battery pack and the motor;
a second switching element coupled between the second battery pack and the motor; and
a controller coupled to the first switching element and the second switching element, the controller havinga first pulse-width modulation (PWM) output coupled to the first switching element and outputting a first PWM signal to selectively close the first switching element, anda second PWM output coupled to the second switching element and outputting a second PWM signal to selectively close the second switching element,wherein a first duty cycle of the first PWM signal and a second duty cycle of the second PWM signal are determined by the controller based on a state of charge of the second battery pack relative to a state of charge of the first battery pack.
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Abstract
A power tool including a motor, a first battery pack, a second battery pack, a first switching element coupled between the first battery pack and the motor, a second switching element coupled between the second battery pack and the motor, and controller coupled to the first switching element and the second switching element. The controller includes a first pulse-width modulation (PWM) output coupled to the first switching element and a first PWM signal to selectively close the first switching element. The controller further includes a second PWM output coupled to the second switching element and a second PWM signal to selectively close the second switching element.
97 Citations
21 Claims
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1. A power tool comprising:
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a motor; a first battery pack; a second battery pack; a first switching element coupled between the first battery pack and the motor; a second switching element coupled between the second battery pack and the motor; and a controller coupled to the first switching element and the second switching element, the controller having a first pulse-width modulation (PWM) output coupled to the first switching element and outputting a first PWM signal to selectively close the first switching element, and a second PWM output coupled to the second switching element and outputting a second PWM signal to selectively close the second switching element, wherein a first duty cycle of the first PWM signal and a second duty cycle of the second PWM signal are determined by the controller based on a state of charge of the second battery pack relative to a state of charge of the first battery pack. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of operating a power tool having a motor, a first battery pack, a second battery pack, a first switching element coupled between the first battery pack and the motor, a second switching element coupled between the second battery pack and the motor;
- and a controller, the method comprising;
determining, by the controller, a state of charge of the first battery pack; determining, by the controller, a state of charge of the second battery pack; generating, by the controller, a first pulse-width modulation (PWM) signal to selectively close the first switching element to present power from the first battery pack to the motor, the first PWM signal based on the state of charge of the first battery pack; generating, by the controller, a second PWM signal to selectively close the second switching element to present power from the second battery pack to the motor, the second PWM signal based on the state of charge of the second battery pack; and driving the motor by the first battery pack and the second battery pack asynchronously, wherein a first duty cycle of the first PWM signal and a second duty cycle of the second PWM signal are determined by the controller based on the state of charge of the second battery pack relative to the state of charge of the first battery pack. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
- and a controller, the method comprising;
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18. A power tool comprising:
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a motor; a first battery pack; a second battery pack; a first switching element coupled between the first battery pack and the motor; a second switching element coupled between the second battery pack and the motor; a first reverse current blocking element coupled in series between the first battery pack and the first switching element; a second reverse current blocking element coupled between the second battery pack and the second switching element; a first current sensor coupled in series between the first switching element and the first reverse current blocking element; a second current sensor coupled between the second switching element and the second reverse current blocking element; and a controller coupled to the first switching element and the second switching element, the controller having a first pulse-width modulation (PWM) output coupled to the first switching element and outputting a first PWM signal to selectively close the first switching element, and a second PWM output coupled to the second switching element and outputting a second PWM signal to selectively close the second switching element. - View Dependent Claims (19)
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20. A power tool comprising:
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a motor; a first battery pack; a second battery pack; a first switching element coupled between the first battery pack and the motor; a second switching element coupled between the second battery pack and the motor; a first reverse current blocking element coupled in series between the first battery pack and the first switching element; a second reverse current blocking element coupled between the second battery pack and the second switching element; and a controller coupled to the first switching element and the second switching element, the controller having a first pulse-width modulation (PWM) output coupled to the first switching element and outputting a first PWM signal to selectively close the first switching element, and a second PWM output coupled to the second switching element and outputting a second PWM signal to selectively close the second switching element, wherein the controller, for each PWM cycle over a period of PWM cycles, controls the first reverse current blocking element to close after the first switching element is closed, and controls the first reverse current blocking element to open before the first switching element opens.
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21. A method of operating a power tool having a motor, a first battery pack, a second battery pack, a first switching element coupled between the first battery pack and the motor, a second switching element coupled between the second battery pack and the motor;
- and a controller, the method comprising;
determining, by the controller, a state of charge of the first battery pack; determining, by the controller, a state of charge of the second battery pack; generating, by the controller, a first pulse-width modulation (PWM) signal to selectively close the first switching element to present power from the first battery pack to the motor, the first PWM signal based on the state of charge of the first battery pack; generating, by the controller, a second PWM signal to selectively close the second switching element to present power from the second battery pack to the motor, the second PWM signal based on the state of charge of the second battery pack; driving the motor by the first battery pack and the second battery pack asynchronously; blocking current flowing from the first switching element to the first battery pack when the second switching element is closed using a first reverse current blocking element; blocking current flowing from the second switching element to the second battery pack when the first switching element is closed using a second reverse current blocking element; generating a third PWM signal that controls the first reverse current blocking element; and generating a fourth PWM signal that controls the second reverse current blocking element.
- and a controller, the method comprising;
Specification