POWER TOOL POWERED BY POWER SUPPLIES HAVING DIFFERENT RATED VOLTAGES
A power tool is provided including a brushless motor having a rotor and a stator. A power supply interface is arranged to selectively receive a first power input from a first power supply having a first nominal voltage and a second power input from a second power supply having a second nominal voltage, where the second nominal voltage is less than the first nominal voltage. A motor control circuit is provided including a power switch circuit having a power switches disposed between the power supply interface and the motor, and a controller outputting drive signals to the power switches within each phase of the motor to control power supplied to the brushless motor from the power supplies. Each phase is associated with a conduction band (CB). The controller sets the conduction band for each phase to a first CB value when receiving power from the first power supply and to a second CB value that is less that the first CB value when receiving power from the second power supply.
1 . A power tool comprising:
a housing;
a brushless motor including a rotor and a stator having at least three stator windings corresponding to at least three phases of the motor, the rotor being moveable by the stator when the stator windings are appropriately energized within the corresponding phases;
a power supply interface arranged to selectively receive supply of electric power from at least one of a first power supply having a first nominal voltage and/or a second power supply having a second nominal voltage, wherein the second nominal voltage is less than the first nominal voltage; and
a motor control circuit comprising: a power switch circuit having a plurality of power switches disposed between the power supply interface and the motor, and a controller interfaced with the plurality of power switches and configured to output a drive signal to one or more of the plurality of power switches within each phase of the motor to control power supplied to the brushless motor from the at least one of the first power supply and/or the second power supply, each phase being associated with a conduction band (CB) within which the controller outputs the drive signal to one or more of the plurality of power switches associated with the respective phase to energize the corresponding stator windings;
wherein the controller is configured to set the conduction band for each phase to a first CB value when receiving power from the first power supply and to a second CB value that is less that the first CB value when receiving power from the second power supply.
2 . The power tool of claim 1 , wherein at least one of the first power supply or the second power supply is an Alternating-Current (AC) power supply providing AC power, and the motor control circuit comprises a rectifier circuit configured to convert the AC power to a rectified voltage signal and provide the rectified voltage signal to the power switch circuit.
3 . The power tool of claim 1 , wherein the rectifier circuit comprises a diode bridge and a bus capacitor arranged in parallel to the diode bridge on a DC bus line inputted to the power switch circuit.
4 . The power tool of claim 1 , wherein at least one of the first power supply or the second power supply is a Direct-Current (DC) power supply comprising at least one removable battery pack coupled to the power supply interface.
5 . The power tool of claim 1 , wherein an operating voltage range of the motor encompasses the first nominal voltage but does not encompass the second nominal voltage, and the controller is configured to set the conduction band to a baseline value of 120 degrees when receiving power from the first power supply and to an increased conduction value in the range of 130 to 180 degrees when receiving power from the second power supply to boost supply of power from the second power supply to the motor.
6 . The power tool of claim 5 , wherein the operating voltage range of the motor is approximately within a range of 100V to 120V, and the second nominal voltage is in a range of approximately 60 VDC to 80 VDC.
9 . The power tool of claim 1 , wherein an operating voltage range of the motor encompasses neither the first nominal voltage nor the second nominal voltage, the first nominal voltage is above the operating voltage range of the motor and the second nominal voltage is below the operating voltage range of the motor, and the controller is configured to set the first CB value below 120 degrees so as to reduce supply of power from the first power supply to the motor to correspond to the operating voltage range of the motor when the first power supply is coupled to the power supply interface, and set the second CB value above 120 degrees so as to boost an effective supply of power from the second power supply to the motor to correspond to the operating voltage range of the motor when the second power supply is coupled to the power supply interface.
10 . The power tool of claim 9 , wherein the operating voltage range of the motor is approximately within a range of 150V to 170V, the first nominal voltage is in a range of approximately 220 VAC to 240 VAC, the second nominal voltage is in a range of approximately 90 VDC to 120 VDC.
11 . The power tool of claim 1 , wherein the operating voltage range of the motor encompasses neither the first nominal voltage nor the second nominal voltage, both the first nominal voltage and the second nominal voltage are below the operating voltage range of the motor, and the controller is configured to set both the first CB value and the second CB value to greater than 120 degrees so as to boost an effective supply of power from either the first power supply or the second power supply to the motor to correspond to the operating voltage range of the motor when either the first power supply or the second power supply is coupled to the power supply interface.
12 . The power tool of claim 11 , wherein the operating voltage range of the motor is approximately within a range of 150V to 170V, the first nominal voltage is in a range of approximately 100 VAC to 120 VAC, the second nominal voltage is in a range of approximately 90 VDC to 120 VDC.
13 . The power tool of claim 1 , wherein the controller is configured to set an advance angle (AA) by which the conduction band is advanced for each phase of the motor to a first AA value when receiving power from the first power supply and to a second AA value that is less that the first AA value when receiving power from the second power supply.
14 . A power tool comprising:
a housing;
a brushless motor including a rotor and a stator having at least three stator windings corresponding to at least three phases of the motor, the rotor being moveable by the stator when the stator windings are appropriately energized within the corresponding phases;
a power supply interface arranged to selectively receive supply of electric power from at least one of a first power supply having a first nominal voltage and/or a second power supply having a second nominal voltage, wherein the second nominal voltage is less than the first nominal voltage; and
a motor control circuit comprising: a power switch circuit having a plurality of power switches disposed between the power supply interface and the motor, and a controller interfaced with the plurality of power switches and configured to output a drive signal to one or more of the plurality of power switches within each phase of the motor to control power supplied to the brushless motor from the at least one of the first power supply and/or the second power supply, each phase being associated with a conduction band (CB) within which the controller outputs the drive signal to one or more of the plurality of power switches associated with the respective phase to energize the corresponding stator windings, and an advance angle (AA) representing an angle by which the conduction band is advanced;
wherein the controller is configured to set the advance angle for each phase to a first AA value when receiving power from the first power supply and to a second AA value that is less that the first AA value when receiving power from the second power supply.
15 . The power tool of claim 14 , wherein at least one of the first power supply or the second power supply is an Alternating-Current (AC) power supply providing AC power, and the motor control circuit comprises a rectifier circuit configured to convert the AC power to a rectified voltage signal and provide the rectified voltage signal to the power switch circuit.
16 . The power tool of claim 14 , wherein at least one of the first power supply or the second power supply is a Direct-Current (DC) power supply comprising at least one removable battery pack coupled to the power supply interface.
17 . The power tool of claim 14 , wherein an operating voltage range of the motor encompasses the first nominal voltage but does not encompass the second nominal voltage, and the controller is configured to set the first AA value to 30 degrees when receiving power from the first power supply and the second AA value in the range of 40 to 60 degrees when receiving power from the second power supply to boost supply of power from the second power supply to the motor.
18 . The power tool of claim 14 , wherein an operating voltage range of the motor encompasses neither the first nominal voltage nor the second nominal voltage, the first nominal voltage is above the operating voltage range of the motor and the second nominal voltage is below the operating voltage range of the motor, and the controller is configured to set the first AA value below 30 degrees so as to reduce supply of power from the first power supply to the motor to correspond to the operating voltage range of the motor when the first power supply is coupled to the power supply interface, and set the second AA value above 30 degrees so as to boost an effective supply of power from the second power supply to the motor to correspond to the operating voltage range of the motor when the second power supply is coupled to the power supply interface.
19 . The power tool of claim 1 , wherein the operating voltage range of the motor encompasses neither the first nominal voltage nor the second nominal voltage, both the first nominal voltage and the second nominal voltage are below the operating voltage range of the motor, and the controller is configured to set both the first AA value and the second AA value to greater than 30 degrees so as to boost an effective supply of power from either the first power supply or the second power supply to the motor to correspond to the operating voltage range of the motor when either the first power supply or the second power supply is coupled to the power supply interface.
20 . The power tool of claim 14 , wherein the controller is configured to the conduction band to a first CB value when receiving power from the first power supply and to a second CB value that is less that the first AA value when receiving power from the second power supply.