A variable-flux memory motor and methods of controlling a variable-flux motor

Abstract

In one embodiment, an embodiment of the present invention relates to a multi-pole rotor of a variable flux memory motor (VFMM) comprising a rotor core; and a plurality of poles. Each pole comprises one or more flexible rotor magnets; a first iron wedge; and a second iron wedge: one or more flexible rotor magnets are disposed between the first and second iron wedges in the circumferential direction of the rotor.

Description

Technology Field

[0001] This application claims priority pursuant to 35 USC § 119(e) to U.S. Patent Application No. 16 / 383,274 filed April 12, 2019. The entire contents thereof are incorporated herein by reference. Background Technology

[0002] Synchronous electric motors equipped with permanent magnets, such as variable-flux memory motors, have a wide range of applications in industrial, commercial, and residential sectors due to their high efficiency, including fans, pumps, compressors, elevators, refrigerators, industrial machinery, and electric motor vehicles. Additionally, since permanent magnets are used instead of windings in the rotors of synchronous electric motors, rotor cooling is not required. Along with other advantages (e.g., brushless design), these benefits make synchronous electric motors popular in applications requiring high torque, high efficiency, or low maintenance. Prior art literature

[0003] Japanese Patent Publication No. JP Hei 02-223342 (September 5, 1990) Japanese Patent Publication No. JP 2009-017694 (January 22, 2009)

[0004] Huang Jia ET AL. ‘Variable flux Memory Motors: A Review’. ITEC Asia-Pacific 2014. August 2014, pages 1-6 (2014.08.31.) means of solving the problem

[0005] In one embodiment, an embodiment of the present invention is guided to a multi-pole rotor of a variable-flux memory motor (VFMM) comprising a rotor core; and a plurality of poles: each pole comprises one or more soft rotor magnets; a first ferrous wedge; and a second ferrous wedge: one or more soft rotor magnets are disposed between the first and second ferrous wedges in the circumferential direction of the rotor.

[0006] In one aspect, an embodiment of the present invention is guided by a method for controlling the magnetization state of a VFMM. The method comprises receiving a command to change the magnetization state; determining an ideal magnetization state based on the command; measuring a back electromotive force generated by a magnet of the VFMM; determining a real-time magnetization state of the magnet based on the measured back electromotive force; determining a d-axis current pulse based on the difference between the ideal magnetization state and the real-time magnetization state; and transmitting a d-axis current pulse to the stator windings of the VFMM to adjust the real-time magnetization state so that the absolute value of the difference between the ideal magnetization state and the adjusted real-time magnetization state is within a predetermined threshold value.

[0007] In one embodiment, an embodiment of the present invention is guided by a system for a VFMM. The system comprises a VFMM; and a controller: the VFMM comprises a rotor comprising a rotor core and a plurality of poles; and a stator: each pole of the rotor comprises one or more flexible rotor magnets; a first iron wedge; and a second iron wedge: one or more flexible rotor magnets are disposed between the first iron wedge and the second iron wedge. The stator comprises first, second, and third stator windings corresponding to first, second, and third magnetization phases, respectively; and at least one sense coil for measuring the magnetization state of the VFMM: the controller controls the magnetization state of the VFMM based on the magnetization state of the VFMM measured through the sense coil. The controller adjusts the magnetization state of the VFMM through a current pulse of at least one of the first, second, and third stator windings.

[0008] Other aspects of the present invention will become apparent from the following description and appended claims. Brief explanation of the drawing

[0009] Figure 1 illustrates a synchronous electric motor. FIG. 2 illustrates a cross-sectional view of a variable-flux memory motor (VFMM) according to one or more embodiments of the present invention. FIGS. 3a-3b illustrate two drawings of a rotor of a VFMM according to one or more embodiments of the present invention. FIG. 4a illustrates the magnetization direction in a cross-sectional view of a portion of a VFMM according to one or more embodiments of the present invention. FIG. 4b illustrates a cross-sectional view of a portion of a VFMM according to one or more embodiments of the present invention. FIGS. 5a-5b illustrates the distribution of magnetic flux in a cross-sectional view of a VFMM according to one or more embodiments of the present invention. FIG. 6a illustrates a simplified circuit model of the stator winding of a VFMM according to one or more embodiments of the present invention. FIG. 6b illustrates the stator winding of a VFMM according to one or more embodiments of the present invention. FIG. 6c illustrates a simplified circuit model of the stator winding and sensing coil of a VFMM according to one or more embodiments of the present invention. FIG. 7 illustrates a flowchart illustrating a magnetization method of a VFMM according to one or more embodiments of the present invention. FIG. 8 illustrates a flowchart illustrating a magnetization method of a VFMM according to one or more embodiments of the present invention. FIG. 9 illustrates a diaphragm according to one or more embodiments of the present invention. Specific details for implementing the invention

[0010] Specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Identical elements in the various drawings are indicated by the same reference numerals for consistency.

[0011] In the following detailed description of embodiments of the present invention, numerous specific details are presented to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without these specific details. In other cases, well-known features have not been described in detail to avoid making the description unnecessarily complex.

[0012] FIG. 1 illustrates an exploded perspective view of a synchronous electric motor (100, synchronous electric motor) (hereinafter referred to as the “synchronous motor”) comprising a rotor (101), a stator (102), and a stator winding (103) arranged around a rotor hub (104). The synchronous motor may also include a terminal box for connecting an input power source, a cooling fan, a rotor position sensor, a temperature sensor, a liquid cooling housing, etc. The rotor (101) includes multiple poles each comprising a permanent magnet (105) (PM).

[0013] A synchronous motor (100) operates via a three-phase AC input in which each phase is delayed by 120 degrees compared to the other two phases. To generate the three-phase AC input, a power converter can convert DC power supplied to a current converter from a high-voltage DC source (e.g., a battery). By applying the three-phase AC input to the synchronous motor, the stator windings generate a three-phase magnetic field that interacts with the magnetic field of the PM (105) and causes the rotor (101) to rotate at a constant rotational speed per minute (RPM) (hereinafter referred to as "RPM") in a steady-state. The RPM of the synchronous motor is determined by the number of poles, available voltage, and flux linkage (λ m It is fixed to a limiting factor such as ), which is provided and fixed by the PM. Synchronous motors have a wide range of applications in industrial, commercial, and residential sectors, such as fans, pumps, compressors, elevators and refrigerators, industrial machinery, and electric vehicles.

[0014] In one or more embodiments, λ provided by PM mBecause this is fixed, a synchronous motor having a PM has a narrow constant power speed range (CPSR), which is a speed range in which the motor's drive can maintain constant power with limiting values ​​for the motor's input voltage and current. Therefore, it is difficult to increase the CPSR of a synchronous motor without using advanced control techniques, such as implementing flux-weakening control methods. Due to the narrow range of CPSR for synchronous motors, it may be necessary to use a transmission system to change the CPSR of a system driven by a synchronous motor. Even using such advanced methods, the CPSR of a synchronous motor is extended to 2 to 3. Meanwhile, the CPSR of a VFMM according to one or more embodiments can achieve 4 to 6.

[0015] Generally, embodiments of the present invention relate to the design of a VFMM, a rotor for a VFMM, and a method for magnetizing a VFMM. A VFMM is a type of synchronous motor in which the magnetization of the rotor magnet (RM) of the VFMM can be adjusted (i.e., changed) during the operation of the VFMM. Adjustment of the magnetization of the RM (hereinafter referred to as "VFMM magnetization" for convenience) changes the RPM of the VFMM. According to one or more embodiments, to facilitate the change of VFMM magnetization, the RM is made of a soft-ferromagnetic material such as aluminum nickel cobalt (AlNiCo) or some type of ceramic. Hereinafter, an RM made of a soft-ferromagnetic material will be referred to as a "soft RM." According to one or more embodiments, the soft RM is AlNiCo or AlNiCo, having grades 1 to 9. It may be a cast, ceramic, a magnet composed of some grades of samarium cobalt, or a sintered construction of these materials. It is evident to those skilled in the art that specific amounts of these materials can be used to achieve the desired function of the VFMM.

[0016] A VFMM according to one or more embodiments is a better alternative to synchronous motors because the maximum achievable RPM at the limiting voltage of the VFMM can be achieved more efficiently by changing the VFMM magnetization. That is, the CPSR can have a wider range compared to the CPSRDP of the synchronous motor. Therefore, there is no need to connect the transmission system to the VFMM. Consequently, according to one or more embodiments, using a VFMM potentially reduces the manufacturing cost of electric motor-equipped systems because it is magnetized or magnetized during assembly.

[0017] Ductile ferromagnetic materials have high permeability (same as hard ferromagnetic materials, such as alloys of iron and nickel) but low coercivity (unlike hard ferromagnetic materials). Due to the low coercivity of ductile ferromagnetic materials, changing the magnetization of ductile ferromagnetic materials requires a relatively small magnetic field compared to hard ferromagnetic materials.

[0018] In one or more embodiments, only soft RMs may be used as magnets for the rotor of the VFMM, and hard magnets (i.e., magnets made of hard-ferromagnetic materials) mounted on the rotor may be absent. Alternatively, in one or more embodiments, both soft RMs and hard magnets may be used as magnets for the rotor of the VFMM. Embodiments of the present invention may have advantages over synchronous motors using only hard magnets because hard magnets are made of rare-earth materials and are significantly more expensive than soft RMs (e.g., AlNiCo). Therefore, when hard RMs are used partially or wholly instead of hard magnets in the VFMM, the manufacturing cost of the VFMM is significantly reduced compared to conventional synchronous motors.

[0019] In addition, another advantage of using a soft RM is that the control and change of the total magnetization of the entire magnet of the VFMM can be performed over a wide range. According to one or more embodiments, the total magnetization of the soft RM can be changed to any value from 0% magnetization (i.e., the soft RM is fully magnetized) to 100% magnetization (i.e., the soft RM is magnetized to its maximum capacity). Such magnetization changes can occur in a short time (e.g., about 1 millisecond).

[0020] In contrast, hard magnets do not tend to change their magnetization easily. Therefore, changing the magnetization of hard magnets requires significantly more power than the operating power of VFMMs or other types of synchronous motors. For example, changing the magnetization of hard magnets, such as some grades of neodymium iron boron (NdFeB) and samarium cobalt (SmCo), can require more than 10 times the power required to change the magnetization of soft RMs. Consequently, when using hard magnets in VFMMs, the magnetization of the hard magnets cannot be changed unless a high current is applied to the stator windings. However, such high currents can damage the windings or other components of the electric motor.

[0021] According to one or more embodiments, if a current significantly higher than the operating current of the stator winding passes through the stator winding, this current may temporarily change the magnetization of the soft RM to an undesirable value. This current (hereinafter referred to as "glitch current") may be generated due to an undesirable glitch in the VFMM or the controller controlling the VFMM. However, the magnetization of the soft RM can be easily restored by another current that the stator winding can withstand. No matter how high the glitch current is, the magnetization of the soft RM can be restored through a current relatively smaller than the glitch current (compared to a hard magnet) because the soft RM can easily accommodate a different magnetization.

[0022] On the other hand, if a synchronous motor with soft magnets (such as VFMM) contains hard magnets and a glitch current changes the magnetization of the hard magnets, it will be difficult to restore the magnetization of the hard magnets through the current in the stator windings. Such a current capable of restoring the hard magnets may be too high to withstand by the stator windings or other parts of the synchronous motor. For example, such high currents could burn out the stator windings or dispotentiate various elements of the synchronous motor, such as the rotor and windings. To restore the hard magnets, the synchronous motor must be opened, the hard magnets must be separated from the synchronous motor, and they must be placed under a high magnetic field.

[0023] In one or more embodiments, a specific number or amount of hard magnets may be used to create a magnetization baseline for the VFMM. Since the magnetization of the hard magnets is resistant to change, the magnetization of the hard magnets will become the magnetization baseline, and the magnetization of the soft magnets will change the overall magnetization from the magnetization baseline (to a higher or lower magnetization from the baseline depending on the torque and RPM of the VFMM).

[0024] FIG. 2 illustrates a cross-sectional view of a VFMM (200) according to one or more embodiments of the present invention. The VFMM (200) of FIG. 2 includes a stator (201) and a rotor (203) that hold stator windings in slots between adjacent stator teeth (202). The rotor (203) includes a flexible RM (204) and an iron wedge (205) mounted on a rotor core (206). The rotor (203) is mounted on a shaft (208). The rotor (203) includes a sleeve (207) that holds the flexible RM (204) and the iron wedge (205) together. The sleeve (207) may have a radial thickness of 0.5 to 3 millimeters (mm). The thickness is determined by the centrifugal force applied by the flexible RM (204) and the iron wedge (205). Alternatively, in one or more embodiments, the sleeve (207) may be attached to any one of the flexible RM (204), iron wedge (205), and / or rotor core (206).

[0025] In these embodiments, the sleeve (207) may be made of a non-binding material that is not attached to the flexible RM (204), iron wedge (205), and / or rotor core (206). The non-binding sleeve (207) may be made of carbon fiber HEX TOW IM10 or Kevlar tow (i.e., kevlar twine). Alternatively, the sleeve (207) may be part of the rotor assembly.

[0026] The d-axis (direct axis) and q-axis (orthogonal axis) are illustrated in FIG. 2. The D-axis is the axis where the magnetic field of the rotor is maximum. For example, the d-axis in FIG. 2 is in the middle of the adjacent poles, which are between the adjacent iron wedges (205) where the magnetic field of the rotor (203) is highest. The Q-axis is 90 degrees phase away from the d-axis. For example, the q-axis in FIG. 2 is between the flexible RMs (204) of each pole where the magnetic field of the rotor (203) is lowest.

[0027] According to one or more embodiments, the rotor comprises a plurality of poles, and each pole comprises one or more flexible RMs. In one or more embodiments, each pole may comprise a plurality of flexible RMs. For example, the rotor (300) illustrated in FIG. 3a-3b comprises 10 poles around the rotor core (306), and each pole comprises 8 flexible RMs (302) (i.e., segments) arranged next to each other in the circumferential direction (308) and axial direction (312) between two iron wedges (304). In the viewing direction along the axial direction (312) (illustrated in FIG. 3b), there are rows of flexible RMs (302) arranged next to each other such that 4 flexible RMs are arranged next to each other in each row.

[0028] In another embodiment, depending on the specific design and function of the VFMM as well as manufacturing constraints, the number of columns of flexible RM (302) may be more or less than 2, and the number of flexible RM (302) in each column may be more or less than 4.

[0029] According to one or more embodiments, the advantage of having multiple flexible RMs (302) on the pole rather than having a single RM is not only to reduce eddy currents of the flexible RMs (302) during VFMM operation, but also to provide more defined control of the magnetic field direction inside the VFMM. When the flexible RMs (302) or other conductive elements of the VFMM are in a time-varying magnetic flux, such as AC magnetic flux, eddy currents are induced in the flexible RMs (302) and other conductive elements of the VFMM. The eddy currents of the flexible RMs (302) generate heat. When multiple flexible RMs (302) are used, small air gaps at the interfaces of adjacent flexible RMs (302) help reduce eddy currents because they stop the eddy currents being conducted between adjacent flexible RMs (302). Thus, eddy currents and resistive losses will be reduced.

[0030] According to one or more embodiments, the rotor core (306) may be wholly or partially non-conductive and / or non-magnetic. For example, the rotor core (306) may be made of polyamide-imide, G10, thermoplastic materials, three-dimensional printed materials, Delrin, etc. The non-conductive rotor core (306) may be significantly lighter than conventional rotor cores made of metals such as aluminum and laminated or solid magnetic steel. According to one or more embodiments, eddy currents cannot be generated in the non-conductive rotor core (306). Therefore, the non-conductive rotor core (306) remains colder than conventional metallic rotor cores. In addition, reducing or omitting the eddy current of the rotor core (306) has an advantage because it reduces the parasitic magnetic flux generated by the eddy current that interferes with the magnetic flux generated by the stator winding.

[0031] Magnetic flux interference can reduce the efficiency and controllability of the VFMM's magnetization.

[0032] According to one or more embodiments, the rotor (300) may be mounted on a polygonal (e.g., hexagonal) shaft (314) for better grip between the rotor (300) and the shaft (314), that is, for better torque transmission between the shaft (314) and the rotor (300). Those skilled in the art will understand that other shapes may be used for the shaft (314) depending on the purpose of the rotor (300).

[0033] According to one or more embodiments, the flexible RM and the iron wedge are designed to magnetize the flexible RM more efficiently than before. The efficiency of VFMM magnetization increases when magnetic flux outside the flexible RM (dissipated magnetic flux) is removed and, instead, the magnetic flux is guided into the flexible RM through the iron wedge. To remove magnetic flux dissipation, the flexible RM and the iron wedge are designed to create the most efficient path for the magnetic flux inside the flexible RM. Hereinafter, the average direction of the magnetic flux inside the flexible RM will be described as the "magnetization direction." According to one or more embodiments, the iron wedge may have a triangular shape to efficiently guide the magnetic flux into the flexible RM. For example, the iron wedge may be similar to the iron wedge (304) shown in FIGS. 3a-3b.

[0034] FIG. 4a illustrates various magnetization directions inside the flexible RM (402) in a cross-sectional view of a VFMM including a flexible RM (402) that accommodates the end of the stator winding (412), an iron wedge (404), a rotor core (406), a stator tooth (408), and a stator slot (410).

[0035] The magnetization direction of FIG. 4a is indicated by the inclination of the magnetization direction in the Cartesian coordination system defined in FIG. 4a, where the "X" and "Y" axes are parallel to the interface between the flexible RMs (402), and the Y axis is perpendicular to the X axis and the rotor axis. When the inclination of the magnetization direction in the Cartesian coordination system is "S", the magnetization direction is defined as "+X / S+Y" and "-X / S+Y" at the upper and lower flexible RMs (402), respectively.

[0036] According to one or more embodiments, current conduction in the stator winding (412) generates magnetic flux in the air gap (414) between the rotor and the stator. The iron wedge (404) guides the magnetic flux in the air gap (414) to the flexible RM (402) to magnetize the flexible RM (402).

[0037] According to one or more embodiments, the efficiency of a VFMM, which is the percentage of the total output mechanical power of the VFMM relative to the input power of the VFMM, depends on the direction of magnetization. Increasing the efficiency of electric motors is very important in the industry, and an improvement in efficiency of even within 1% is considered important in the industry. Efficiency is calculated using numerical software (Finite Element Analysis) and experimentally verified. All known mechanical losses, including electrical and mechanical losses, are taken into account in the efficiency calculation. The effect of VFMM magnetization on efficiency is more pronounced in electromagnetic losses. Electromagnetic losses include resistance losses of the stator windings, resistance losses due to eddy currents, and losses due to the loss of magnetic flux by escaping from permeable regions (e.g., iron wedges and RMs) (hereinafter referred to as stray losses).

[0038] Table 1 below shows the efficiency for various magnetization directions according to one or more embodiments.

[0039] Test case Magnetization direction Efficiency (%) Average torque (nm) 1 Circumferential (not manufacturable) 96.8 402.8 2 +Y 96.88 406.9 3 +X / 4+Y 96.8 401.7 4 +X / 8+Y 96.92 406.3 5 +X / 16+Y 96.93 407.23 6 -X / 16+Y 96.8 402.08 7 +X / 32+Y 96.915 406.5

[0040] In Table 1, the magnetization direction for "Test Case 1" is the circumferential direction, which means that the average direction of the magnetic flux inside the flexible RM follows the circumference of the rotor. For example, referring to FIG. 3b, the average direction of the magnetic flux inside the flexible RM (302) may follow the circumferential direction (308).

[0041] According to one or more embodiments, the geometries of the flexible RM (402), iron wedge (404), and rotor core (406) are optimized to achieve the magnetization direction of Table 1.

[0042] Table 2 below shows five different designs, each containing exemplary geometrical factors of a soft RM and an iron wedge, with reference to Fig. 4b, which result in the optimal magnetization direction to achieve the highest power efficiency at the minimum mass of the VFMM. The geometrical factors in Table 2 correspond to various magnetization directions according to one or more embodiments. These geometrical factors were achieved through the optimization method to obtain the efficiency shown in Table 1.

[0043] Parameters Design 1 Design 2 Design 3 Design 4 Design 5 Magnet Depth (cm) 2.25 2.0 2.0 2.0 1,5 Magnet Fraction (%) 58 42 42 70 70 Magnet Material AlNiCo 9 AlNiCo 9 AlNiCo 5 AlNiCo 9 AlNiCo 9 Rotor Inert Radius (cm) 7.55 7.0 7.0 7.0 7.0 Optimal Magnetization Direction -X / 16+Y -X / 8+Y -X / 8+Y -X / 8+Y -X / 5+Y Torque 396 320 256 370 303 Efficiency 94.4 93.1 87.7 94.5 93

[0044] Figure 4b corresponds to the example in Table 2.

[0045] As illustrated in FIG. 4b, the magnet depth (422) of Table 2 is the radial thickness of the flexible RM (402). The magnet fraction of Table 2 is the angle (θ) corresponding to the flexible RM (402) for each pole in the cross-sectional view of the rotor. m ) and the angle (θ) corresponding to the entire pole p It is the percentage ratio between ). For example, if the rotor contains 10 poles, θ p 36 degrees = 360 / P. Here, "P" is the number of poles. In this example, a magnetic fraction of 58% is 100 × θ m / θ p It is identical to. Therefore, θ in this example m It will be 20.88 degrees. The rotor inert radius (424) is the radial distance between the flexible RM (402) and the center of the rotor, as shown in FIG. 4b. As shown in FIG. 4b, in the example of Table 2, each of the iron wedges (404) has a triangular shape.

[0046] The design shown in Table 2 is an example of a rotor for achieving a corresponding magnetization direction, but those skilled in the art understand that embodiments of the present invention are not limited to this example and that the values ​​of the geometric factors in Table 2 can be achieved through optimization and computational simulation to achieve a specific magnetization direction depending on the design or manufacturing constraints of the VFMM.

[0047] For example, the magnetization direction can be determined through simulation using commercial finite element method (FEM) software. In FEM software, the geometric shape of the VFMM can be defined by constructing a three-dimensional model of the VFMM, and the magnetization direction can be determined by computationally solving electromagnetic equations for the VFMM model in the electromagnetic module of the FEM software. To determine more accurate and universal performance of the VFMM, the FEM software may have multiple modules, such as a thermal transfer module and a mechanical stress module, that can be coupled to the electromagnetic module of the FEM software.

[0048] In one or more embodiments, the variables in Table 2 may be changed in FEM simulations to obtain different magnetization directions. For example, the magnet depth, magnet fraction, or rotor inert radius of Design 1 may be changed (i.e., adjusted) to achieve a magnetization direction different from -X / 16+Y.

[0049] In one or more embodiments, the geometric shape of the rotor may be formulated, and an optimization method may be applied to the formulated geometric shape to achieve an optimal magnetization direction. For example, the edges and iron wedge (404) of the rotor RM (402) of FIG. 4c may be defined through the following equations (1)-(7).

[0050] (1) The first end of the edge (4021) is at point "A" in FIG. 4c, which is x=(ri+drb+dm)×cos(-α m ×180° / P+qrr-180° / P) and y=(ri+drb+dm)×sin(-α m It is located at ×180 degrees / P+qrr-180 degrees / P). The second end of edge (4021) is at point "C", which is x=(ri+drb+dm)×cos(α m ×180° / P+qrr-180° / P) and y=(ri+drb+dm)×sin(α m It is at ×180 degrees / P+qrr-180 degrees / P). The curvature of the edge (4021) between the first end and the second end of the edge (4021) is 360 degrees / P.

[0051] (2) The first end of edge (4022) is at point "B", which is x=(ri+drb)×cos(-α m ×180° / P+qrr-180° / P) and y=(ri+drb)×sin(-α m It is located at ×180 degrees / P+qrr-180 degrees / P). The second end of edge (4022) is at point "D", which is x=(ri+drb)×cos(α m ×180° / P+qrr-180° / P) and y=(ri+drb)×sin(α m It is at ×180 degrees / P+qrr-180 degrees / P). The curvature of the edge (4022) between the first end and the second end of the edge (4022) is 360 degrees / P.

[0052] (3) The edge (4023) is a straight line between points A and B.

[0053] (4) Edge (4024) is a straight line between points C and D.

[0054] (5) The iron wedge (404) shares the edge (4024) with the flexible PM (402).

[0055] (6) The edge (4042) of the iron wedge (404) starts at point C and at E (α i -αm It ends with a curve of )×180 degrees / P.

[0056] (7) The edge (4041) of the iron wedge (404) is a straight line between point D and point E.

[0057] In the above formulas (1)-(7), "ri" is the rotor inert radius, "drb" is the rotor back iron, "dm" is the magnet depth (4025), and "α m is the scaled magnet fraction. For example, if the magnet fraction is 58%, α m is 0.58. "α i " is 1-α m It is equivalent to. "P" is the number of poles. "qrr" is equivalent to ωt+θ, where "ω", which is theta, is the angular velocity of the rotor, "t" is time, and "θ" is the angle offset.

[0058] In one or more embodiments, the gap (418) between the flexible RM or iron wedge and the stator (hereinafter referred to as the “gap”), which may include an air gap (414) and a non-magnetic sleeve (420), may not have a direct effect on the magnetization direction. However, the gap (418) may affect efficiency because more energy is required to pass magnetic flux from the stator winding through the gap (418), which may have a magnetic permeability of about 1. In one or more embodiments, the gap (418) may be about 2.25 mm such that 0.9 mm is occupied by the sleeve (420) and 1.35 mm is the air gap (414) between the sleeve (420) and the stator.

[0059] FIGS. 5a and 5b show magnetic flux in cross-sectional views of a VFMM for magnetization directions of ±X / 4+Y and ±X / 16+Y, respectively. These figures illustrate how the magnetization direction affects the efficiency of the VFMM. In these figures, an iron wedge (504) conducts the magnetic flux generated by the stator windings to the flexible RM (502). The rotor core (506) is selected from non-conductive / non-magnetic polyamide-imide to prevent shunting of the magnetic flux by the rotor core (506). Thus, most of the magnetic flux enters the flexible RM (502) and is magnetized.

[0060] According to one or more embodiments, the shape and size of the flexible RM (502) and the iron wedge (504) determine the efficiency of magnetizing the flexible RM (502) and the dissipation of magnetic flux to the outside of the flexible RM (502). For example, there is less stray (508) of magnetic flux for the magnetic direction of ±X / 16+Y (shown in FIG. 5b) than for the magnetic direction of ±X / 4+Y (shown in FIG. 5a). Consequently, the magnetization of the flexible RM (502) is more efficient in the magnetic direction of ±X / 16+Y than in the magnetic direction of ±X / 4+Y. The stray (508) of magnetic flux is an example of the aforementioned stray losses.

[0061] According to one or more embodiments, the stator windings generate the magnetic flux necessary to magnetize the VFMM and rotate the rotor. FIG. 6a illustrates a simplified circuit model of stator windings wound in a wye configuration. There are three stator windings (i.e., a first stator winding (601A), a second stator winding (601B), and a third stator winding (601C)) that carry phases A, B, and C lagging 120 degrees from each other. For example, if phase A is 0, phase B is 120 degrees and phase C is -120 degrees. The three stator windings are connected to a null. Each of the three stator windings may include multiple winding coils that are wound in the same direction and connected to each other.

[0062] FIG. 6b illustrates how three stator windings are wound on a stator as an example according to one or more embodiments. Each stator winding comprises a plurality of winding coils. In the example illustrated in FIG. 6b, each stator winding for phases A, B, and C comprises 20 winding coils. For each of the three phases, the winding coil carries a single phase (i.e., one of phases A, B, and C).

[0063] In the example illustrated in FIG. 6b, each stator slot (602) accommodates one end of one winding coil and one end of another winding coil. For example, the stator slot (2) illustrated in the enlarged view of FIG. 6b includes an upper section (2T) that accommodates the end of the winding coil for phase A and a lower section (2B) that accommodates the end of the winding coil for phase B.

[0064] Table 3 below shows an example of a winding coil for the stator winding of FIG. 6b.

[0065] Number of winding coils (Winding Coil Number) Phase group (Phase Group) rotation (Turns) In slot (In Slot) Out slot (Out Slot) Coil_1 A1 5 2T Lead 11B Coil_2 A1 14 3T 10B Coil_3 A1 14 4T 9B Coil_4 A1 5 5T 8B Finish Coil_5 B1 5 6T Lead 15B Coil_6 B1 14 7T 14B Coil_7 B1 14 8T 13B Coil_8 B1 5 9T 12B Finish Coil_9 C1 5 10T Lead 19B Coil_10 C1 14 11T 18B Coil_11 C1 14 12T 17B Coil_12 C1 5 13T 16B Finish Coil_13 A2 5 14T Lead 23B Coil_14 A2 14 15T 22B Coil_15 A2 14 16T 21B Coil_16 A2 5 17T 20B Finish Coil_17 B2 5 18T Lead 27B Coil_18 B2 14 19T 26B Coil_19 B2 14 20T 25B Coil_20 B2 5 21T 24B Finish Coil_21 C2 5 22T Lead 31B Coil_22 C2 14 23T 30B Coil_23 C2 14 24T 29B Coil_24 C2 5 25T 28B Finish Coil_25 A3 5 26T Lead 35B Coil_26 A3 14 27T 34B Coil_27 A3 14 28T 33B Coil_28 A3 5 29T 32B Finish Coil_29 B3 5 30T Lead 39B Coil_30 B3 14 31T 38B Coil_31 B3 14 32T 37B Coil_32 B3 5 33T 36B Finish Coil_33 C3 5 34T Lead 43B Coil_34 C3 14 35T 42B Coil_35 C3 14 36T 41B Coil_36 C3 5 37T 40B Finish Coil_37 A4 5 38T Lead 47B Coil_38 A4 14 39T 46B Coil_39 A4 14 40T 45B Coil_40 A4 5 41T 44B Finish Coil_41 B4 5 42T Lead 51B Coil_42 B4 14 43T 50B Coil_43 B4 14 44T 49B Coil_44 B4 5 45T 48B Finish Coil_45 C4 5 46T Lead 55B Coil_46 C4 14 47T 54B Coil_47 C4 14 48T 53B Coil_48 C4 5 49T 52B Finish Coil_49 A5 5 50T Lead 59B Coil_50 A5 14 51T 58B Coil_51 A5 14 52T 57B Coil_52 A5 5 53T 56B Finish Coil_53 B5 5 54T Lead 3B Coil_54 B5 14 55T 2B Coil_55 B5 14 56T 1B Coil_56 B5 5 57T 60B Finish Coil_57 C5 5 58T Lead 7B Coil_58 C5 14 59T 6B Coil_59 C5 14 60T 5B Coil_60 C5 5 1T 4B Finish

[0066] In Table 3, phase groups A1-A5 carry the same phase A, phase groups B1-B5 carry the same phase B, and phase groups C1-C5 carry the same phase C. The winding coils of each phase group (e.g., phase group A1) can be connected in series with each other, and the phase groups for each phase (e.g., A) can be connected in parallel with each other. For example, the winding coils for phase group A1 are connected in series with each other, and phase groups A1-A5 are connected in parallel with each other.

[0067] In the example shown in Table 3, coil-1 (the winding coil of phase group A1) is wound five times between the top part of slot 2 (2T) and the bottom part of slot 11 (11B). Then, the same wire is continued to be wound between 3T and 10B, with coil-2 for the same phase group A1 being wound 14 times in the same direction as coil-1. Similarly, coil-3 and coil-4 for phase group A1 are wound in series in the same direction as coil-1 and coil-2. The lead and finish wire-ends of phase group A1 are located in slots 2T and 8B, respectively.

[0068] In Table 3, the other phase groups are wound similarly to phase group A1.

[0069] According to one or more embodiments, phases A, B, and C may each have a sensing coil (in addition to the winding coil) to measure the magnetization state (MS) of the soft RM. Thus, there may be three sensing coils (i.e., first, second, and third sensing coils). The sensing coils may be placed in or embedded in the stator windings, but the sensing coils are electrically insulated from the stator windings. FIG. 6c illustrates a simplified circuit model of first, second, and third stator windings (601A, 601B, and 601C, respectively) having phases A, B, and C wound in a Y-shaped circuit configuration, each having corresponding first, second, and third sensing coils (604A, 604B, and 604C, respectively). Those skilled in the art will understand that the stator windings and sensing coils may be wound in a Δ (delta) configuration to achieve specific functions.

[0070] In one or more embodiments, since a high current pulse may be required to magnetize or demagnetize the soft RM, the stator winding may be wound in a Y-shaped circuit configuration, and the current pulse in the power line of the VFMM for each phase is equal to the current of the stator winding for that phase. Thus, the current of the stator winding can be directly controlled and can be simply measured by controlling and measuring the current of the power line. However, in a Δ configuration, the current of the stator winding does not necessarily have to be equal to the current of the power line.

[0071] In one or more embodiments, a sensing coil inductively generates a back electromotive force (bemf) using the magnetic flux of the soft RM. The intensity (amplitude) of the bemf represents the MS of the soft RM and the rotor position. The bemf has parameters with fixed values, such as inductances and resistances. The bemf also has parameters with variable values, such as angular velocity, angular position, and current. In one or more embodiments, these fixed and variable value parameters must be known in order to measure the MS of the soft RM.

[0072] Table 4 illustrates an example of winding a sensing coil according to one or more embodiments.

[0073] 감지 코일수 (Sense Coil Number) 위상 (Phase) 회전(Turns) 인 슬롯(In Slot) 아웃 슬롯(Out Slot) Coil_1 A1 1 2T Lead 11B Coil_2 A1 1 3T 10B Coil_3 A1 1 4T 9B Coil_4 A1 1 5T 8B Finish Coil_5 B1 1 6T Lead 15B Coil_6 B1 1 7T 14B Coil_7 B1 1 8T 13B Coil_8 B1 1 9T 12B Finish Coil_9 C1 1 10T Lead 19B Coil_10 C1 1 11T 18B Coil_11 C1 1 12T 17B Coil_12 C1 1 13T 16B Finish Coil_13 A2 1 14T Lead 23B Coil_14 A2 1 15T 22B Coil_15 A2 1 16T 21B Coil_16 A2 1 17T 20B Finish Coil_17 B2 1 18T Lead 27B Coil_18 B2 1 19T 26B Coil_19 B2 1 20T 25B Coil_20 B2 1 21T 24B Finish Coil_21 C2 1 22T Lead 31B Coil_22 C2 1 23T 30B Coil_23 C2 1 24T 29B Coil_24 C2 1 25T 28B Finish Coil_25 A3 1 26T Lead 35B Coil_26 A3 1 27T 34B Coil_27 A3 1 28T 33B Coil_28 A3 1 29T 32B Finish Coil_29 B3 1 30T Lead 39B Coil_30 B3 1 31T 38B Coil_31 B3 1 32T 37B Coil_32 B3 1 33T 36B Finish Coil_33 C3 1 34T Lead 43B Coil_34 C3 1 35T 42B Coil_35 C3 1 36T 41B Coil_36 C3 1 37T 40B Finish Coil_37 A4 1 38T Lead 47B Coil_38 A4 1 39T 46B Coil_39 A4 1 40T 45B Coil_40 A4 1 41T 44B Finish Coil_41 B4 1 42T Lead 51B Coil_42 B4 1 43T 50B Coil_43 B4 1 44T 49B Coil_44 B4 1 45T 48B Finish Coil_45 C4 1 46T Lead 55B Coil_46 C4 1 47T 54B Coil_47 C4 1 48T 53B Coil_48 C4 1 49T 52B Finish Coil_49 A5 1 50T Lead 59B Coil_50 A5 1 51T 58B Coil_51 A5 1 52T 57B Coil_52 A5 1 53T 56B Finish Coil_53 B5 1 54T Lead 3B Coil_54 B5 1 55T 2B Coil_55 B5 1 56T 1B Coil_56 B5 1 57T 60B Finish Coil_57 C5 1 58T Lead 7B Coil_58 C5 1 59T 6B Coil_59 C5 1 60T 5B Coil_60 C5 1 1T 4B Finish

[0074] The windings of the sensing coils in Table 4 should be mapped similarly to the winding coils in Table 3. For example, the sensing coils for phase group A1 can be connected in series with each other, and phase groups A1-A5 can be connected in parallel with each other.

[0075] It will be obvious to those skilled in the art that, based on the desired design to achieve a specific function, the windings of the winding coil and the sensing coil may differ from Tables 3 and 4.

[0076] According to one or more embodiments, the voltage between the three wires of the sensing coil shown in FIG. 6c is measured, and then a conversion ratio is applied to obtain the actual voltage between the phases of the stator winding.

[0077] The switching ratio is the ratio of the number of turns between the sensing coil and the stator winding. For example, if the stator winding is wound according to Table 3, the number of turns for each stator winding is 190. If only one turn of the sensing coil is used for each winding coil in Table 3, the number of turns of the sensing coil for each phase is 20. Therefore, the switching ratio in this case is 20 / 190 It is 0.105. In one or more embodiments, the conversion rate for a 175kW VFMM may be 0.0874.

[0078] In one or more embodiments, the MS of the flexible RM is equation λ m =V s It is determined based on / (K×ω), where λ m is the magnetic flux linkage, and V s ε is the measured voltage of the sensing coil, ω is RPM and is a constant in the steady-state, and K is a constant related to the structural values ​​of the VFMM, such as d-axis and q-axis resistance, inductance, and switching ratio, which are fixed in the steady-state. In the steady-state, the constants K and ω and the V induced in the sensing coil s If it has λ m This can be determined. And then, MS is λ m Multiplying by the conversion ratio to λ m It can be obtained from, which is a constant and depends on the design of the VFMM.

[0079] In one or more embodiments, the above equation can be extended as follows.

[0080] V q = (r s ×I q )+(λ m ×ω)+(ω×L d ×I d )

[0081] Here, V qis the q-axis voltage induced in the sensing coil, and L d is the d-axis inductance, and I d is the d-axis current, and I q is the q-axis current, and r s λ is the resistance of the sensing coil in each phase and is a constant. m To measure, I d is considered as 0 and I q is equal to the phase current passing through the field-oriented controller controlling the VFMM. Therefore, V measured by the sensing coil q Knowing , the constant r in the steady state s , I q By having and ω, λ m Can decide.

[0082] According to one or more embodiments, I supplied to the stator winding d The pulse can change the magnetization of the VFMM, and consequently, change the RPM of the VFMM. Due to the ability to change the MS of the flexible RM, the maximum RPM of the VFMM can be changed. Therefore, the VFMM can be used without requiring a transmission system to change the torque-to-speed ratio of the electric motor.

[0083] According to one or more embodiments, the controller controls the magnetization of the soft RM. The controller may determine the MS of the soft RM based on a bemf waveform (hereinafter referred to as "bemf") measured by a sensing coil. In one or more embodiments, the controller may store and organize information and may command a VFMM drive (e.g., inventor, power supply, etc.) to change the magnetization of the soft RM according to the information. The controller may be a computer comprising a processor (e.g., CPU) coupled to memory (e.g., RAM) to perform control of the MS.

[0084] FIG. 7 illustrates a flowchart showing a method of manually controlling the MS of a flexible RM and, accordingly, manually controlling the torque of the VFMM using a controller. Hereinafter, manual control of the MS is a controlling procedure in which an initial command to change the torque and, consequently, the MS is initiated by a human. As a non-limiting example, if the VFMM is a motor of an electric vehicle, the command may be a gear shift or a command from the driver to increase the speed of the electric vehicle. Alternatively, if the VFMM is a motor of an industrial machine, the command may be generated through input from the operator's control panel.

[0085] In step 705 (S705), the control unit receives a command to change MS. For example, the command may be an increase or decrease in motor torque / RPM that requires changing MS.

[0086] In S710, the controller determines and sets the ideal MS based on the command received from S705. For example, if the command is a gear shift, the ideal MS is determined based on a preliminary analysis (e.g., a table (database)) that associates the most optimal MS with the optimal MS for the selected gear. For example, Gear 1 can be associated with 100% MS, while Gear 2 can be associated with 80% MS.

[0087] According to one or more embodiments, 100% MS may be the MS of a soft RM that is magnetized to the full capacity of the soft RM, which is defined (or limited) to the maximum magnetization based on the specific design or function of the VFMM, or magnetized to the magnetization of the soft RM. Meanwhile, 0% MS is the MS of a soft RM that is completely demagnetized.

[0088] In another example according to one or more embodiments, when a command to achieve a desired RPM / torque is received, the controller may find an ideal MS from a table (database) that associates the desired RPM / torque with an ideal MS. Table 5 below shows an exemplary table (database) that associates a desired RPM / torque with an ideal MS.

[0089] RPM Torque (N.m.) Ideal MS (%) 1000 100 100 2000 200 100 4000 400 100 6000 250 75 (±5%) 6000 150 75 (±5%) 12000 100 50 (±5%) 18000 50 22 (±5%)

[0090] In S715, the controller measures the bemf of the VFMM. According to one or more embodiments, bemf is the voltage generated in the sensing coil by the rotor. bemf is λ by a constant factor m It is proportional to. Therefore, bemf represents the real-time MS (i.e., the actual MS of the soft RM at the time of measurement).

[0091] In S720, the controller can correct the value of bemf measured in S715 from transient errors. For example, due to transient operation of the VFMM or power converter, the measured bemf may contain transient errors / noises (e.g., sparks, vibrations, etc.) that do not project real-time MS.

[0092] In S725, the controller determines the real-time MS based on the bemf. For example, the controller may determine the real-time MS based on a table (database) that associates various bemf values ​​with the values ​​of the real-time MS. In one or more embodiments, the controller determines the real-time MS based on the bemf corrected in S720. Alternatively, the controller may use an uncorrected bemf value to determine the real-time MS.

[0093] In one or more embodiments, the controller may determine the real-time MS from an uncorrected or corrected bemf, and then the controller may apply some correction (e.g., filtering noise) to the value real-time MS to obtain the final value of the real-time MS.

[0094] According to one or more embodiments, after the command from S705, the real-time MS and the ideal MS can be determined simultaneously. To do this, S715 to S725 can be performed simultaneously with S710.

[0095] In S730, the controller subtracts the ideal MS obtained in S710 from the real-time MS obtained in S725 to obtain the magnetization difference (ΔMS). If the absolute value of ΔMS ≤ threshold value (e.g., 5% of the ideal MS), the real-time MS is sufficiently close to the ideal MS and there is no need to change the real-time MS. Otherwise, the controller proceeds to S735 described below.

[0096] In S735, the controller I based on ΔMS acquired in S730 d Determines and sets the pulse. For example, the controller sets various values ​​of ΔMS I d Based on a table (database) associated with pulse values, I d You can determine the pulse.

[0097] In S740, the controller is the I determined in S735 d Commands the VFMM to send pulses to the stator windings. For example, this command is I d It can be sent to a power converter to generate pulses and send them to the stator windings.

[0098] According to one or more embodiments, I d The duration, shape, or number of pulses can be determined based on the torque / RPM of the VFMM. According to one or more embodiments, Id The duration of the pulse may be about 1 millisecond (ms).

[0099] In one or more embodiments, after S740, the controller may return to S715 to determine whether ΔMS is within a threshold and re-execute S715 and the steps after S715. If ΔMS is not within the threshold, the controller may use another I to adjust the real-time MS. d A pulse is applied. This process may continue until the real-time MS is adjusted so that ΔMS is within the threshold.

[0100] Figure 8 illustrates a flowchart showing a method for automatically controlling the MS of a flexible RM using a controller. In the following, the automatic control of the MS is a control process that automatically adjusts the MS based on the RPM and torque of the VFMM to maintain the highest power efficiency of the VFMM.

[0101] In S805, the controller measures the RPM of the VFMM.

[0102] In S810, the controller determines the torque of the VFMM. According to one embodiment, the controller may determine the torque based on the measured bemf in S820 and / or S825 described below.

[0103] In S815, the controller determines and sets an ideal MS corresponding to the criteria set for the VFMM. For example, the criteria may be the maximum efficiency (e.g., power efficiency) based on the RPM and torque, minimum magnetic signature, minimum coil temperature, etc., determined in S805 and S810, respectively. For example, the controller accesses a table (database) that associates RPM and torque values ​​with ideal MS values, and this serves as the set criteria. From this table (database), the controller determines the ideal MS corresponding to the measured RPM and torque.

[0104] FIG. 9 illustrates a column graph of the power efficiency of the VFMM with respect to RPM and torque for an example where the setting criterion is power efficiency. In one or more embodiments, each point in the efficiency map of the VFMM represents power efficiency, and the ideal MS is associated with that point.

[0105] In S820, the controller measures the bemf of the VFMM. This is similar to the aforementioned S715. According to one or more embodiments, the controller also measures the λ of the VFMM based on the bemf. m It can calculate . And then, the controller λ m Based on this, the torque for S810 can be determined.

[0106] For example, torque can be calculated based on the following equation.

[0107] Torque = (3 / 2)×(number of poles / 2)×λ m ×I q ,

[0108] Here, λ m is determined based on bemf.

[0109] In S825, the controller can correct the bemf measured in S715 from transient errors. This may be similar to S720 described earlier. According to one embodiment, the controller λ based on the corrected bemf m It can calculate . Alternatively, the controller can calculate λ based on the uncorrected bemf. m After calculating, λ from the transient error m It can be corrected.

[0110] In S830, the controller determines the real-time MS based on the corrected bemf. This may be similar to the S725 described earlier. According to one embodiment, the controller λ m Real-time MS can be determined based on this. For example, the controller can use various λ values ​​for the real-time MS.m You can query real-time MS from a table (database) that associates values.

[0111] S835 is similar to S730. Additionally, according to one or more embodiments, if the absolute value of ΔMS ≤ threshold, the real-time MS is ideal and there is no need to change the real-time MS. In this case, the controller can return to S805. Otherwise, the controller continues to S840.

[0112] The S840 is similar to the S735 described earlier.

[0113] The S845 is similar to the S740 described earlier.

[0114] In one or more embodiments, after S845, the controller may return to S820 to determine whether ΔMS is within a threshold and re-execute S820 and the steps after S820. If ΔMS is not within the threshold, the controller may use another I to adjust the real-time MS. d A pulse is applied. This process may continue until the real-time MS is adjusted so that ΔMS is within the threshold.

[0115] In one or more embodiments, the steps of the manual and automatic control of the MS described with reference to FIG. 7-8 may be performed in a different order than the foregoing unless otherwise specified. The steps may be omitted or performed multiple times to achieve the desired control of the MS.

[0116] Although the present invention has been described in relation to a limited number of embodiments, those skilled in the art will understand that other embodiments may be devised without departing from the scope of the invention as disclosed herein. Accordingly, the scope of the present invention should be limited only by the appended claims.

Claims

Claim 1 As a multi-pole rotor of a variable flux memory motor (VFMM), the rotor comprises: a rotor core—the rotor core is mounted on a shaft and the rotor core is non-conductive—; and a plurality of poles; each of the poles comprises: one or more soft rotor magnets; a first iron wedge; A multi-pole rotor comprising: a first iron wedge and a second iron wedge; wherein one or more flexible rotor magnets are disposed between the first iron wedge and the second iron wedge in the circumferential direction of the rotor, the inner circumferential surface of the rotor core is fitted into the shaft, the rotor core forms the plurality of poles on the outer circumferential surface of the rotor core with the one or more flexible rotor magnets, the first iron wedge and the second iron wedge, and the one or more flexible rotor magnets, the first iron wedge and the second iron wedge are in contact with the outer circumferential surface of the rotor core, and the magnetization state of the VFMM is controlled in real time by a controller based on the magnetization state of the VFMM measured through a sensing coil. Claim 2 In claim 1, the one or more soft rotor magnets comprise a combination of aluminum, nickel, and cobalt, forming a multi-pole rotor. Claim 3 In paragraph 2, the one or more soft rotor magnets are multi-pole rotors, each being AlNiCo of grades 1-9. Claim 4 In claim 1, the multi-pole rotor, wherein the rotor core is made of polyamide-imide. Claim 5 A multi-pole rotor according to claim 1, wherein the one or more flexible rotor magnets comprise a plurality of flexible rotor magnets arranged next to each other in the axial direction of the rotor or in the circumferential direction of the rotor. Claim 6 A multi-pole rotor according to claim 1, further comprising: a sleeve that prevents the one or more soft rotor magnets, the first iron wedge, and the second iron wedge from being separated from the rotor core. Claim 7 In claim 1, the one or more flexible rotor magnets can be magnetized using a stator, and the stator includes a first stator winding, a second stator winding, and a third stator winding corresponding to a first magnetization phase, a second magnetization phase, and a third magnetization phase, respectively, and the first stator winding, the second stator winding, and the third stator winding generate a magnetic flux to magnetize the one or more flexible rotor magnets, and during the magnetization, the magnetic flux enters the one or more flexible rotor magnets from the first iron wedge and the second iron wedge, a multi-pole rotor. Claim 8 In claim 7, the stator comprises: a first sensing coil disposed on or in the first stator winding; a second sensing coil disposed on or in the second stator winding; and a third sensing coil disposed on or in the third stator winding; wherein the first sensing coil, the second sensing coil, and the third sensing coil are electrically insulated from the first stator winding, the second stator winding, and the third stator winding, and the first sensing coil, the second sensing coil, and the third sensing coil each inductively generate a back EMF through the inductance of the magnetic flux generated by the first stator winding, the second stator winding, the third stator winding, and the one or more soft rotor magnets, and the back EMF is an indicator of the magnetization state of the one or more soft rotor magnets, a multi-pole rotor. Claim 9 A multi-pole rotor according to claim 8, wherein the first sensing coil, the second sensing coil, and the third sensing coil measure the magnetization state of the VFMM, and the stator further includes the controller, and the controller adjusts the magnetization state of the VFMM through at least one current pulse of the first stator winding, the second stator winding, and the third stator winding. Claim 10 A method for controlling the magnetization state of a variable flux memory motor (VFMM), wherein the method comprises: receiving a command to change the magnetization state of the variable flux memory motor (VFMM) - wherein the VFMM comprises a rotor core and a plurality of poles, the rotor core is mounted on a shaft, the rotor core is non-conductive, each of the poles comprises one or more flexible rotor magnets, a first iron wedge and a second iron wedge, the one or more flexible rotor magnets are positioned between the first iron wedge and the second iron wedge in the circumferential direction of the rotor, the inner circumferential surface of the rotor core is fitted into the shaft, the rotor core forms the plurality of poles on the outer circumferential surface of the rotor core, and the one or more flexible rotor magnets, the first iron wedge and the second iron wedge are in contact with the outer circumferential surface of the rotor core -; determining an ideal magnetization state based on the command A method comprising: a step of measuring a back electromotive force generated by a magnet of the VFMM; a step of determining a real-time magnetization state of the magnet based on the measured back electromotive force; a step of determining a d-axis current pulse based on the difference between the ideal magnetization state and the real-time magnetization state; and a step of transmitting the d-axis current pulse to a stator winding of the VFMM to adjust the real-time magnetization state so that the absolute value of the difference between the ideal magnetization state and the adjusted real-time magnetization state is within a predetermined threshold value. Claim 11 A method according to claim 10, wherein the ideal magnetization state is determined based on a database that associates the torque and speed of the VFMM with the values ​​of the ideal magnetization state. Claim 12 A method according to claim 10, wherein the real-time magnetization state is determined based on a database that associates the measured back electromotive force with the value of the real-time magnetization state. Claim 13 In paragraph 10, the above back EMF is inductively measured through a sensing coil. Claim 14 A method according to claim 10, further comprising the step of correcting a transient error of the measured back EMF; wherein the real-time magnetization state of the magnet is determined based on the corrected back EMF. Claim 15 In claim 10, the above ideal magnetization state is determined based on the torque and speed of the VFMM. Claim 16 In claim 15, the method further comprises a controller configured to determine the torque based on the back EMF in the VFMM. Claim 17 In paragraph 15, the method wherein the ideal magnetization state is determined based on a database that associates the speed and torque of the VFMM with the values ​​of the ideal magnetization state that result in maximum efficiency at the speed and torque of the VFMM. Claim 18 In paragraph 15, the method wherein the real-time magnetization state is determined based on a database that associates the measured back electromotive force with a value for the real-time magnetization state. Claim 19 In paragraph 15, the back electromotive force is inductively measured through a sensing coil. Claim 20 A method according to claim 15, further comprising the step of correcting a transient error of the measured back EMF; wherein the real-time magnetization state of the magnet is determined based on the corrected back EMF. Claim 21 As a system for a variable flux memory motor (VFMM), the variable flux memory motor (VFMM); and a controller; wherein the VFMM comprises a rotor including a rotor core - the rotor core is mounted on a shaft and the rotor core is non-conductive - a plurality of poles - each pole includes one or more flexible rotor magnets, a first iron wedge and a second iron wedge, the one or more flexible rotor magnets are disposed between the first iron wedge and the second iron wedge, the inner circumferential surface of the rotor core is fitted into the shaft, the rotor core forms the plurality of poles on the outer circumferential surface of the rotor core, and the one or more flexible rotor magnets, the first iron wedge and the second iron wedge are in contact with the outer circumferential surface of the rotor core - and a stator - comprising a first stator winding, a second stator winding and a third stator winding and at least one sensing coil corresponding to a first magnetization phase, a second magnetization phase and a third magnetization phase, respectively, and the sensing A system comprising a coil that measures the magnetization state of the VFMM, and a controller that controls the magnetization state of the VFMM based on the magnetization state of the VFMM measured through the sensing coil, and adjusts the magnetization state of the VFMM through at least one current pulse of the first stator winding, the second stator winding, and the third stator winding. Claim 22 In claim 10, the above VFMM further comprises a stator, wherein the stator comprises a first stator winding, a second stator winding, and a third stator winding corresponding to a first magnetization phase, a second magnetization phase, and a third magnetization phase, respectively, and the first stator winding, the second stator winding, and the third stator winding generate a magnetic flux to magnetize the one or more soft rotor magnets, and during the magnetization, the magnetic flux enters the one or more soft rotor magnets from the first iron wedge and the second iron wedge.

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