JP6643980B2 - Improved switch reluctance motor and switch reluctance device for hybrid vehicles - Google Patents

Description

This application claims the priority and benefit of United States Provisional Application No. 61 / 878,135, filed September 16, 2013, which gives priority to the filing date. The description, drawings and all disclosures of US Provisional Application No. 61 / 878,135 are hereby incorporated by reference for all purposes.
The present invention generally relates to the field of hybrid vehicles. More particularly, the present invention relates to an apparatus for increasing, storing and storing vehicle motive energy of an internal combustion-electric hybrid vehicle using a switched reluctance motor.

A motor generator device that can be retrofitted to an internal combustion powered vehicle and adds electrical power and power to the vehicle is disclosed in Perry et al., "Machine for Augmentation, Storage, and Conservation of Vehicle Motive Energy," US 2012/0215389. And is incorporated herein by reference for all purposes. Earlier hybrid drive systems are disclosed in U.S. Pat. 4,165,795 by Lynch et al. And U.S. Pat. No. 4,335,429 by Kawakatsu, which are hereby incorporated by reference for all purposes.

The present invention relates to an improved hybrid drive device having a switched reluctance hub motor as shown in FIGS. By using a switched reluctance motor, the present invention has the advantage of removing the drag caused by the magnetic field present in motors used in the prior art by turning off the magnetic field when not in use. The present invention also has the advantage that when the magnetic field is turned off, the magnetic road dust or debris drawn in during operation is dropped or driven away, thereby operating cleaner and more efficiently.

FIG. 1 shows a diagram of a system according to an embodiment of the present invention. FIG. 2 shows a diagram of an apparatus according to an embodiment of the present invention. FIG. 3 shows a diagram of a switched reluctance motor with a central rotor with rotor bars. FIG. 4 shows a diagram of a switched reluctance motor with rotoring. FIG. 5 is an enlarged view of FIG. FIG. 6 is a diagram showing the switched reluctance motor of FIG. 4 in a state where the rotor has moved to the second position. FIG. 7 is a diagram showing another embodiment of the switched reluctance motor including the rotor ring. FIG. 8 is a diagram showing still another embodiment of the switched reluctance motor including the rotor ring.

Switched reluctance motors are a type of reluctance motor (ie, an electric motor that operates with reluctance torque). Unlike common DC motor types, power is provided to the stator windings rather than the rotor. This simplifies the mechanical design since no power needs to be applied to the moving parts. However, some switching system is needed to be used to apply power to each winding.

In some embodiments, the switched reluctance motor has a wound field coil. However, the rotor does not have any attached magnets or coils. The rotor typically includes a solid salient pole rotor (with protruding magnetic poles) formed from a soft magnetic material (eg, laminated steel). When power is supplied to the stator windings, the magnetic reluctance of the rotor creates a force that attempts to match the rotor with the nearest stator pole. To maintain rotation, the electrical control system switches on successive windings of the stator poles in turn so that the stator magnetic field leads the rotor poles and pulls them forward. Rather than using a mechanical commutator to switch the winding current as in conventional motors, switch reluctance motors determine the angle of the rotor shaft using electronic position sensors and use stator electronics to implement stator windings. Switching lines, which also provide the opportunity for dynamic control of pulse timing and shaping.

FIG. 3 shows an example of a switched reluctance motor. Switched reluctance motors are designed to take advantage of reduced reluctance in magnetic circuits. Generally, a rotor 100 having a plurality of rotor bars 102 rotates inside a stator ring 110. Inside the stator are a plurality of ferromagnetic stator poles 112, which are actuated by magnetic coils 114 around the stator poles to temporarily create N-pole and S-pole magnets. The rotor of the switched reluctance motor is formed from a ferromagnetic material and provides a low reluctance magnetic path from stator pole to stator pole. A magnetic flux path is formed through the corresponding rotor bar 102 from an activated north pole to an activated south pole.

An operation example of the switch reluctance motor is as follows. The stator poles at 90 degrees and 270 degrees (A1, A2) are actuated by magnetic coils around the ferromagnetic stator poles to form north pole and south pole magnets. The magnetic flux path is formed from the north pole to the south pole through the rotor bar (B) coinciding with the stator poles (A1, A2), and is a low reluctance path. The flux path is annular, going from one stator pole around the periphery of the stator ring to the other and returning through the corresponding rotor bar.

The control circuit turns off the current to the stator poles (A1, A2) and activates the stator poles at the 315-degree and 135-degree positions (C1, C2). Programmable control circuits and mechanisms are well known in the art and are readily available. The rotor bar (D), which is slightly offset from the stator poles (C1, C2), is pulled counterclockwise by the just-actuated N and S stator poles (C1, C2). When the rotor bar (D) reaches a new position that coincides with the stator poles (C1, C2), the control circuit turns off the current and supplies current to the 0 and 180 degree stator pole positions (E1, E2), and the rotor bar (D). F) to be pulled counterclockwise. In each case, the high reluctance between the two actuated stator poles ensures that the rotor bars exactly match the stator poles, as in the case of the horizontal rotor bar (B) and stator poles (A1, A2) To be reduced. By electrically operating the stator poles in a clockwise manner, the rotor bar rotates in a counterclockwise manner, thereby creating a motor actuation. Of course, the direction of operation (ie, the direction of rotation) may be reversed.

As mentioned above, a major advantage of switched reluctance motors is that they do not require permanent magnets (as do DC brushless motors). Thus, it is simple and economical to build and works well in environments that contain dirty, ie, ferromagnetic, dust particles. However, switched reluctance motors require control circuitry to activate the stator poles at the correct time, which complicates the switched reluctance motor and increases the likelihood of optical sensors and other suitable techniques. Requires feedback of the rotor position. Also, switched reluctance motors tend to generate noise due to the opposing stator poles being turned on / off, thereby vibrating at audible frequencies due to the periodic alternating on / off forces on the stator ring. Will be.

An improved switched reluctance motor designed to address these shortcomings is described below. In some embodiments, the improved motor has a modified flux path in the rotor, as shown in FIG. The rotor is a rotor ring 200, which rotates inside a stator ring 210. The rotor ring has a plurality of rotor poles 202 arranged on the outer periphery. The stator ring has a plurality of ferromagnetic stator poles 212, which are actuated by magnetic coils 214 around the stator poles to temporarily create north and south pole electromagnets. The opposing stator poles are not operated together as a pair; instead, north and south poles are created by activating multiple stator poles in the same region of the stator ring. As shown in FIGS. 4 and 5, the reduced reluctance flux path travels from one actuated pole through a short distance on the stator ring to the other stator pole, and then to two corresponding rotor poles. And go through the rotoring. As shown in FIG. 2, a brake mounting plate is disposed between the stator ring and the rotor ring.

An example of the operation of the improved switched reluctance motor is as follows. The stator pole (H) is activated by its corresponding coil to produce an N electromagnet, and the stator pole (I) is activated in the same way to produce an S electromagnet. The rotor poles (F), (G) coincide with the stator poles (H), (I), respectively, by the magnetic circuit flowing through them. The path of reduced reluctance in the rotor ring (A) is indicated by an arrow (J), and the path in the stator ring (D) is indicated by an arrow (K). Note that this operation of the stator pair is repeated around the stator ring, creating a plurality of low reluctance magnetic circuits (15 in this configuration) along the motor. The pairs of stator pole electromagnets alternate in N and S directions around the ring.

The control circuit turns off the current to the stator poles (H, I) (and other activated stator pole pairs around the ring) and activates the stator poles (N, O). As a result, as shown in FIG. 6, the rotor poles (L, M) coincide with the stator poles (N, O), and L, N, O, M and the portions of the stator ring and the portion of the rotor ring between them are separated. Create a new low reluctance path through. Note that a new low reluctance magnetic circuit is created around the motor by operation of a similar stator pair.

This rotor movement causes the rotor poles (P, Q) to move to a position where they are then pulled to coincide with the stator poles (H, I) when the stator poles (H, I) are reactivated. This means a two-phase switched reluctance motor in which the operation of (H, I) becomes the first phase and the operation of (N, O) becomes the second phase. In this configuration, at some point in time, every other stator pole is activated (i.e., there is one non-activated stator pole between each activated stator pole of the activated stator pole pair). It should be noted that the motor may have a three-phase configuration or more depending on pole spacing and actuation timing.

FIG. 7 shows an embodiment of a three-phase switched reluctance motor, in which three pairs of stator poles are activated in sequence. At some point, every third stator pole is activated (ie, there are two non-activated stator poles between each activated stator pole of the activated stator pole pair).

The central region (R) is the mechanical support for the rotor ring and includes a non-ferromagnetic material such as, but not limited to, aluminum, brass, carbon fiber, or other suitable material. The central region assists in positioning the rotor with respect to the stator poles and providing rotation about the shaft through the center of the rotor assembly.

The number of rotor and stator poles can be varied. In the embodiment shown in FIG. 4, forty-five rotor poles are fixed on the outer periphery of the rotor ring, and thirty stator poles are fixed on the inner periphery of the stator ring. These numbers can be varied as shown in FIG. 7, where there are 60 rotor poles and 36 stator poles. As shown in FIG. 8, there are many combinations of numbers of stator poles and rotor poles that are configured to function with an annular flux path in the rotor. The numbers of stator poles and rotor poles disclosed in this specification are merely examples of the three embodiments.

The invention enables a very simple drive system in that the motor is driven by a single-phase variable frequency AC signal. The ability to drive this motor with a single-phase AC signal does not limit the choice of arranging the stator and rotor poles to drive the stator pole electromagnet with any of single-phase, two-phase, and three-phase AC. Absent.

This configuration can be driven by a single-phase variable frequency AC signal consisting of a sine wave, a square wave, or any other suitable wave by activating the stator poles alternately. The stator poles (H, N, I, O) make up the complete set of electrical 360 degree cycles of the motor. The 360 degree electrical cycle of the motor is the degree of rotation of the rotor at which a complete electrical cycle is completed and the electrical operation repeats itself. In the motor design shown in FIG. 4, there is a complete 360 degree electrical cycle in a 24 degree rotation of the rotor ring. This means that for 360 degrees of rotation, there are 15 cycles of 360 degrees electrical rotation. The four stator poles allow a complete cycle of two phases to run on the rotor pole. The motor operates by driving the stator poles (H) and (I) with the NS polarity, and then operating the stator poles (N) and (O) with the NS polarity. By alternating the two sets of stator poles in an appropriate sequence, only four stator poles in the sequence are used to rotate the rotor ring clockwise or counterclockwise. The improved switched reluctance motor allows a subset of poles on the stator ring. No conventional switched reluctance motor has this capability.

Another application of this design is to function as a switched reluctance stepper motor. In FIG. 4, as described above, the rotor poles (F) and (G) coincide with the stator poles (H) and (I), and the rotor poles (L) and (M) change from the stator poles (N). , (O) is in a position where it is pulled to match. When the current of the stator poles (H) and (I) is DC, the rotor is held at one fixed position. If the DC current at the stator poles (H) and (I) is cut off and the DC current is supplied to the stator poles (N) and (O), the rotor rotates four degrees counterclockwise and stops. With the proper spacing and geometry of the rotor and stator poles, and the proper supply of current at the correct timing, the present switched reluctance motor functions as a stepper motor as well as a variable speed motor.

While FIGS. 4 and 5 show the radial flux paths, the present invention provides other possible configurations where the flux paths do not run through the full diameter of the rotor, i.e., the rotor bar. Including. For example, FIG. 2 shows a switched reluctance motor having an axial flux configuration. The rotor poles in this embodiment are magnetic steel and not permanent magnets (meaning significant advantages over DC brushless designs, as described elsewhere herein).

The improved switched reluctance motor designed as described above is particularly suitable for high torque applications, including but not limited to wheel hub motors, at low rpm (eg, about 2000 rpm or less). The rpm is low because the motor is a direct drive to the wheels. High starting torque is desirable.

The noise generated by the improved switched reluctance motor design according to the present invention is small compared to prior art designs. Due to the manner of operation of the present motor, the attractive magnetic force between the actuated stator pole and the corresponding rotor pole is not completely zero, so that the force acting on the stator is always constant. This reduces the tendency for vibration in the stator ring.

The embodiments and examples described herein have been chosen and described to better illustrate the principles of the invention and its practical applications, so that those skilled in the art may practice the invention in numerous ways. In form, and with a number of modifications deemed appropriate for the particular use. Although specific embodiments of the present invention have been described, these are not exhaustive. It will be apparent to those skilled in the art that many modifications can be made.

Claims (13)

A switch reluctance motor device including a switch reluctance motor mounted on a wheel hub of a vehicle configured to be retrofittable to an internal combustion powered vehicle, wherein the switch reluctance motor mounted on the hub is
A stator ring with a periphery ,
A plurality of stator poles arranged on the periphery of the stator ring and actuated by magnetic coils to become electromagnets;
A rotor ring having a peripheral edge and disposed adjacent to the stator ring;
A plurality of rotor poles arranged adjacent to the periphery of the rotor ring and close to the stator poles;
A brake mounting plate disposed between the stator ring and the rotor ring,
With
When the stator pole pair is activated, a low reluctance flux path is formed through the stator pole pair and the proximal rotor pole pair,
The low reluctance flux path is formed through a portion of the stator ring between the pair of stator poles and a portion of the rotor ring between the pair of rotor poles.
Motor device. The motor device according to claim 1, wherein the low reluctance magnetic flux path does not pass through a center of the rotor. The motor device according to claim 1, wherein the low reluctance magnetic flux path does not pass through a diameter of the rotor. The motor device according to claim 1, wherein the motor is a two-phase motor. The motor device according to claim 1, wherein the motor is a three-phase motor. The motor device of claim 1, wherein actuation of the stator pole pair pulls the rotor pole pair to match the stator pole. The motor device according to claim 1, wherein the pair of stator poles are continuously operated to rotate the rotor ring. The motor device according to claim 1, wherein the motor is a variable speed motor. The motor device according to claim 1, wherein the motor is a stepper motor. The motor device according to claim 1, wherein the rotor ring is provided on a non-ferromagnetic mechanical support at the center of the rotor ring. Every other stator pole is actuated at a particular time, the corresponding pair of rotor poles through which the low reluctance flux path is formed is every third rotor poles, according to claim 1 Motor device . Every two stator poles, is actuated at a particular time, the corresponding pair of rotor poles through which the low reluctance flux path is formed is every fourth rotor poles, according to claim 1 Motor device . The motor device according to claim 1, wherein the motor is driven by a single-phase variable frequency AC signal.