MOTOR DRIVING APPARATUS
First Claim
1. A motor driving apparatus for a cleaning appliance comprising a battery source and a power controller, the battery source being configured and connected to supply the power controller with an output having a first voltage, the first voltage decreasing as the battery source is discharged, and the power controller being configured and connected to modulate the output to produce a drive signal for driving a motor, the drive signal having a second voltage and a variable duty cycle,wherein the power controller is configured and connected to increase the duty cycle of the drive signal as the first voltage decreases in order to maintain the second voltage at a substantially constant average value per unit time.
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Accused Products
Abstract
A motor driving apparatus for a cleaning appliance includes a battery source and a power controller. The battery source supplies the power controller with an output having a first voltage which decreases as the battery source is discharged. The power controller modulates the output to produce a drive signal for driving a motor that has a second voltage and a variable duty cycle. The power controller increases the duty cycle of the drive signal as the first voltage decreases in order to maintain the second voltage at a substantially constant average value per unit time. By providing the above arrangement, the motor can be supplied with a constant voltage throughout the available run time of the battery. When forming part of a cleaning appliance having a motor, the above arrangement allows the motor to operate at a substantially constant speed throughout the run time of the battery.
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Citations
10 Claims
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1. A motor driving apparatus for a cleaning appliance comprising a battery source and a power controller, the battery source being configured and connected to supply the power controller with an output having a first voltage, the first voltage decreasing as the battery source is discharged, and the power controller being configured and connected to modulate the output to produce a drive signal for driving a motor, the drive signal having a second voltage and a variable duty cycle,
wherein the power controller is configured and connected to increase the duty cycle of the drive signal as the first voltage decreases in order to maintain the second voltage at a substantially constant average value per unit time.
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7. (canceled)
Specification