Methods of and/or apparatus for electronically commutated motor control
First Claim
1. A method of controlling the commutation of power to an electronically commutated motor having a rotor and a stator with energizable windings and switching devices for connecting each winding to a power supply, which uses a controller to set the state of the switching devices to determine commutation sequences of application of voltage to said stator windings to cause torque producing current flow in said stator windings to thereby rotate said rotor, said method comprising the steps of:
- (1) applying voltage to said windings so as to cause said current to flow therein,(2) monitoring the torque-producing current waveform in at least one of said windings to detect occurrences of a predetermined waveform characteristic, said occurrences being cyclical and indicative of rotor position,(3) passing the detected rotor position information to said controller,(4) the controller after each detected occurrence using said information to determine the state said switching devices must attain at the end of a predetermined delay after each detected occurrence to ensure powered rotation of said rotor, and(5) after said predetermined delay causing the controller to place the switching devices in the so determined state.
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Accused Products
Abstract
A method of controlling the commutation of power to an electric motor back EMF sensing or Hall effect sensors is disclosed. At least part of the current waveform is sensed in at least one motor winding and is used to establish information relating to the appropriate commutation pattern required to commutate power to the motor and control motor parameters e.g. motor speed.
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Citations
20 Claims
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1. A method of controlling the commutation of power to an electronically commutated motor having a rotor and a stator with energizable windings and switching devices for connecting each winding to a power supply, which uses a controller to set the state of the switching devices to determine commutation sequences of application of voltage to said stator windings to cause torque producing current flow in said stator windings to thereby rotate said rotor, said method comprising the steps of:
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(1) applying voltage to said windings so as to cause said current to flow therein, (2) monitoring the torque-producing current waveform in at least one of said windings to detect occurrences of a predetermined waveform characteristic, said occurrences being cyclical and indicative of rotor position, (3) passing the detected rotor position information to said controller, (4) the controller after each detected occurrence using said information to determine the state said switching devices must attain at the end of a predetermined delay after each detected occurrence to ensure powered rotation of said rotor, and (5) after said predetermined delay causing the controller to place the switching devices in the so determined state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for controlling the commutation of power to an electronically commutated motor having a rotor and a stator with energizable windings and switching devices for connecting each winding to a power supply, wherein the state of the switching devices is periodically set to determine commutation sequences of application of voltage to said stator windings to cause torque producing current flow in said stator windings to thereby rotate said rotor, said apparatus comprising:
- a stored program controller, the output of which controls the state of said switching devices, means for sensing rotor position consisting of current monitoring means which monitors the torque-producing current waveform in at least one of said windings to detect occurrences of a predetermined waveform characteristic, said occurrences being cyclical and indicative of rotor position, means for gating the detected rotor position information to inputs of said controller, the stored program such that after each detected occurrence of said predetermined waveform characteristic the controller uses said information to determine the state said switching devices must attain at the end of a predetermined delay after each detected occurrence to ensure powered rotation of said rotor, and after said predetermined delay the controller places the switching devices in the so determined state.
- View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
Specification