One challenge in electric motor design has been making more compact motors to fit new applications. A smaller size allows the motor to be packaged with other devices for additional uses. One of the challenges of a compact size is heat dissipation.
The present invention is an integrated brushless permanent-magnet motor with the circuit board controller in the same chamber as the rotor and stator.
The above, as well as other advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:
The circuit is based on a microprocessor controller U6. It communicates to the master controller through connections W3-W7. U9 and its associated circuitry measure the motor current and interface to the microprocessor for controlling the current and protecting against excessive current. U10 and its associated circuitry process the BEMF of the motor and interface with the microcontroller to control the proper sequencing of the energization of the motor windings. U2, U3, U4, as well as Q4, Q5, Q6, Q7, Q8, Q9 and their associated circuitry receive signals from the microprocessor and apply the energizing voltages and currents to the motor windings. U8 measures the temperature of the motor and control and communicates the information to the microprocessor.
This invention may also include features designed to reduce cogging. These features include, but are not limited to, the features described in the patent application for a Slow-Speed Direct-Drive Generator filed concurrently herewith. The features described in that application include the introduction of variations in the airgap using teeth with multiple protrusions on the stator lamination stack and building the teeth into the stator in a particular ratio and with measurements that coordinate the teeth, rotor poles, slot openings, teeth protrusions, and the notches between the teeth protrusions. These features are shown in
The circuitry monitors the speed and accepts other inputs to control the speed of the rotor rotation. If the temperature gets too high or there is a problem, then the circuitry can shut down the motor.
As electricity flows through the stator windings, the shifting magnetic fields cause the rotor to rotate. The shape of the shoes, which have subteeth, and the skew of the magnet reduce the cogging torque and thus increase efficiency.
The heat generated by the circuit board flows out of the circuit board through the connecting metal bars to the back plate, and out of the back plate through its fins. Since the circuit board is in the same chamber as the stator and rotor, this action simultaneously cools the circuit board and the stator and rotor.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.
Number | Date | Country | |
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60831493 | Jul 2006 | US |