Methods of and/or apparatus for braking an electronically commutated motor and/or laundry machines incorporating the same
First Claim
1. A method of braking an electronically commutated motor (ECM) having a rotor and a stator including energisable windings, and using a power supply having an upper and a lower voltage rail, commutating circuitry to supply commutating EMF'"'"'s to said motor, commutation control means controlling at least one switching device for each said winding to selectively connect said windings between said rails, and braking switch for connecting a braking resistance between said rails, when braking is desired, said method comprising the steps of continuing to maintain voltage on said voltage rails and to supply commutating EMF'"'"'s to said motor connecting said braking resistance between said rails and controlling the commutation sequences of said motor by controlling connection of the windings of the motor to said rails by said at least one switching device for each winding in a commutation sequence so that currents flowing in said braking resistance due to back EMF'"'"'s generated in said windings and due to kinetic energy in the rotating rotor are augmented by controlling the phase relationship between the generated back EMF'"'"'s and the commutating EMF'"'"'s applied by said commutating circuitry.
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Abstract
A method of braking an electronically commutated motor (ECM) by connecting a braking resistor across the motor supply rails and controlling the commutation sequences of the motor. The commutation switching devices are controlled to commutate power generated in said windings by rotation of the motor rotor to the power supply ratio. The power commutated to the supply rails is dissipated in the braking resistance to brake the motor.
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Citations
32 Claims
- 1. A method of braking an electronically commutated motor (ECM) having a rotor and a stator including energisable windings, and using a power supply having an upper and a lower voltage rail, commutating circuitry to supply commutating EMF'"'"'s to said motor, commutation control means controlling at least one switching device for each said winding to selectively connect said windings between said rails, and braking switch for connecting a braking resistance between said rails, when braking is desired, said method comprising the steps of continuing to maintain voltage on said voltage rails and to supply commutating EMF'"'"'s to said motor connecting said braking resistance between said rails and controlling the commutation sequences of said motor by controlling connection of the windings of the motor to said rails by said at least one switching device for each winding in a commutation sequence so that currents flowing in said braking resistance due to back EMF'"'"'s generated in said windings and due to kinetic energy in the rotating rotor are augmented by controlling the phase relationship between the generated back EMF'"'"'s and the commutating EMF'"'"'s applied by said commutating circuitry.
- 17. A braking apparatus for braking an electronically commutated motor (ECM) having energisable windings and a rotor, said apparatus comprising a power supply means for supplying power to an upper and a lower voltage rail, commutation circuitry to supply commutating EMF'"'"'s to said motor, commutation control means, at least one switching device for each winding of said motor, said at least one switching device being controlled by said commutation control means and said commutation circuitry for selectively connecting said windings between said upper and lower rails, a braking switch, a braking resistance switchable by said braking switch to be connected between said voltage rails, said commutation control means controlling the commutation of said motor by controlling connection of the windings of the motor to said rails through appropriate said at least one switching device for each winding so that voltage is maintained on said rails and commuting EMF'"'"'s are being supplied to said motor and said braking resistance is connected between said rails, said commutation control means controls the commutation sequences of said motor by controlling connection of the windings of the motor to said rails by said at least one switching device for each winding in a commutation sequence so that currents flowing in said braking resistance due to back EMF'"'"'s generated in said windings and due to kinetic energy in the rotating rotor are augmented by controlling the phase relationship between the generated back EMF'"'"'s and the commutating EMF'"'"'s applied by said commutation circuitry.
Specification