Patent Application
20170163114
The subject matter disclosed herein relates to motor-generators, and more particularly, to a motor-generator with a stator with multiple stator windings.
Flywheel energy storage systems can be used to store energy that may be typically wasted and release energy as needed. Flywheel energy storage systems may utilize supplemental energy storage to increase functionality of the storage system. Often, utilizing multiple sources of energy within a flywheel energy storage system may result in a motor-generator that is large, complex, and cost prohibitive.
According to an embodiment, a motor-generator includes a stator disposed along a centerline including a stator pole, a first stator winding and a second stator winding, wherein the first stator winding is wound on the stator pole and the second stator winding is wound on the stator pole, and at least one rotor axially disposed from the stator along the centerline.
According to an embodiment, an energy storage system includes a flywheel, and a motor-generator including a stator disposed along a centerline including a stator pole, a first stator winding and a second stator winding, wherein the first stator winding is wound on the stator pole and the second stator winding is wound on the stator pole, and at least one rotor operatively coupled to the flywheel, wherein the at least one rotor is axially disposed from the stator along the centerline.
Technical function of the embodiments described above includes that the first stator winding is wound on the stator pole and the second stator winding is wound on the stator pole.
Other aspects, features, and techniques of the embodiments will become more apparent from the following description taken in conjunction with the drawings.
The subject matter is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the embodiments are apparent from the following detailed description taken in conjunction with the accompanying drawings in which like elements are numbered alike in the FIGURES:
Referring now to the drawings,
In the illustrated embodiment, the energy storage system 100 can provide and receive kinetic energy from the wheel 102. In other embodiments, the wheel 102 can be representative of any load that can provide and receive kinetic energy from the energy storage system 100. In the illustrated embodiment, the wheel 102 is driven by a wheel motor 104. Further, the wheel motor 104 can function as a generator to convert kinetic energy from the wheel 102 to electrical energy for use with the energy storage system 100. In certain embodiments, the wheel motor 104 can be a traction motor. In the illustrated embodiment, the wheel motor 104 is a high voltage motor. Further, the wheel motor 104 can be an AC permanent magnet synchronous motor. Advantageously, the wheel motor 104 can be high efficiency and provide high power density.
In the illustrated embodiment, the wheel motor 104 can be electrically connected to the motor-generator 120 via an AC/DC/AC converter 106. In certain embodiments, the AC/DC/AC converter 106 is a three phase, four quadrant converter. In the illustrated embodiment, the AC/DC/AC converter 106 can facilitate bidirectional power transfer to the wheel 102 and from the wheel 102. During a drive mode, power flows to the wheel motor 104 and AC/DC/AC converter 106 operates as a rectifier at the motor-generator 120 side and as an inverter as the wheel motor 104 side as kinetic energy from the flywheel 108 is transferred as kinetic energy of the wheel 102. During braking or other regenerative operations, the AC/DC/AC converter 106 operates as a rectifier at the wheel motor 104 side and as an inverter at the motor-generator 120 side as kinetic energy from the wheel 102 is transferred to the flywheel 108 by facilitating generation operations of the wheel motor 104.
In the illustrated embodiment, the battery 114 can introduce stored chemical energy into the energy storage system 100. The battery 114 can further store and provide energy to the wheel 102. In certain embodiments, the battery 114 may provide energy, but may not provide adequate transient response for immediate power demands as may be required with certain applications, such as vehicles. Therefore, in certain embodiments, the battery 114 can provide energy to the flywheel 108 for use by the energy storage system 100 which may then be rapidly deployed as needed. In the illustrated embodiment, the battery 114 can be representative of any suitable energy source.
In the illustrated embodiment, the battery 114 is electrically connected to the motor-generator 120 via a bidirectional DC/DC converter 112 and a bidirectional AC/DC converter 110. In the illustrated embodiment, the DC/DC converter 112 controls output from the battery 114 to limit output current or alternatively boost battery 114 voltage. Further, the DC/DC converter 112 can be utilized to recharge the battery 114 by using energy from the flywheel 108. In the illustrated embodiment, the AC/DC converter 110 can control the speed and torque of the flywheel 108 while the AC/DC converter functions as an inverter. Further, the AC/DC converter 110 can function as a rectifier as energy stored in the flywheel 108 is sent to the battery 114.
In the illustrated embodiment, the motor-generator 120 is connected to the flywheel 108 either directly, by a gearbox or by a linkage. The flywheel 108 can provide energy storage by storing and releasing kinetic energy to either the wheel motor 104 or the battery 114. The energy storage parameters of the flywheel 108 are determined by the moment of inertia and the rotational speed of the flywheel 108.
The motor-generator 120 can receive electrical energy from the wheel motor 104 and the battery 114 to provide kinetic energy to the flywheel 108. Further the motor-generator 120 can provide electrical energy to the wheel motor 104 and the battery 104 from the kinetic energy of the flywheel 108. As shown in
Referring to
Referring to
In the illustrated embodiment, the high voltage coil winding 340 is wrapped around the same stator pole 328 as the low voltage coil winding 330. In the illustrated embodiment, the high voltage coil winding 340 is a concentrated-parameter coil to allow for enough space for both independent windings 330,340. In certain embodiments, the high voltage coil winding 340 can include 12 coils, which can facilitate the use of three-phase power. In other embodiments, the high voltage coil winding 340 can include any number of coils in multiples of three or any other suitable number of coils which can facilitate the use of three-phase power. In certain embodiments, the high voltage coil winding 340 may experience voltage ranging from 270 to 800 VDC after rectification. In certain embodiments, the high voltage coil winding 340 may experience any suitable DC voltage after rectification. In the illustrated embodiment, the high voltage coil winding 340 is formed from a material and geometry to be suitable for use with the expected voltage and power.
In the illustrated embodiment, the energy storage system 100 can have independent control over each coil winding 330,340. In certain embodiments, the coil windings 330,340 can be utilized to provide redundant control and operation of the motor-generator 320. In certain embodiments, the magnetic coupling between the low voltage coil winding 330 and the high voltage coil winding 340 functions as a transformer by facilitating the step up or step down of voltage via the magnetic coupling there between.
Referring to
In the illustrated embodiment, the rotors 322 include a rotor backing plate 326 and a permanent magnet 324. In the illustrated embodiment, the rotors 322 are coupled to the flywheel 108 to send and receive kinetic energy therefrom. In certain embodiments, the mass of the rotor 322 can be utilized or supplement the energy storage function of the flywheel 108. In certain embodiments, the rotor 322 can be integrated with the flywheel 108. In other embodiments, the mass of the rotor 322 can be utilized as the flywheel 108.
In the illustrated embodiment, the rotors 322 include permanent magnets 324. In other embodiments, the rotors 322 can be wound field rotors utilized with brushless exciters.
Referring to
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments. While the description of the present embodiments has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications, variations, alterations, substitutions or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the embodiments. Additionally, while various embodiments have been described, it is to be understood that aspects may include only some of the described embodiments. Accordingly, the embodiments are not to be seen as limited by the foregoing description, but are only limited by the scope of the appended claims.
