KR20230013910A - Device for Converting Energy - Google Patents

Abstract

An energy conversion device is provided. The energy conversion device comprises: a stator including stator teeth arranged in a circumferential direction from an outer diameter side and an armature wire prepared on the stator teeth; and a rotor prepared on the outside in a radial direction of the stator and having a consequent pole on an inner diameter thereof, wherein the consequent pole is made by alternately arranging a first permanent magnet, a metal pole, and a second permanent magnet having a relatively lower coercive force than the first permanent magnet in a circumferential direction.

Description

Energy conversion device {Device for Converting Energy}

The present invention relates to an energy conversion device, and more specifically, to an energy conversion device in which pole conversion control is easy.

In the case of a motor for a washing machine, two modes are required: a low speed (washing) mode and a high speed (drying) mode. Since the permanent magnet synchronous motor has high efficiency at high speed but low efficiency at low speed, it is preferable to use the permanent magnet synchronous motor in the spin-drying mode, but not in the washing mode. In contrast, vernier machines are suitable for washing mode because they have high efficiency at low speed.

Accordingly, research on the development of one motor having the effect of using two motors is being conducted. The memory machine, which is an existing unidirectional variable magnetic flux device developed first, can change the number of poles by varying the magnetic flux, so it can have a wide speed range.

Afterwards, additional studies were conducted to propose a hybrid memory machine with a wider speed range. The hybrid memory machine is a bidirectional variable magnetic flux device, and uses LCF PM (Low Coercive Force Permanent Magnet) and HCF PM (High Coercive Force Permanent Magnet) with low coercive force.

This device can change the number of poles by changing the magnetization direction of the LCF PM using a pole-changing current. Accordingly, it can have a wider speed range than conventional memory machines, but performance in a specific speed range is not as good as conventional vernier machines or permanent magnet synchronous motors.

In order to compensate for these disadvantages, a PCVM (Pole Changing Vernier Machine) capable of changing modes has been proposed. The PCVM has the advantages of both the vernier machine and the permanent magnet synchronous motor described above.

PCVM not only changes the number of poles by changing the direction of magnetization of the LCF PM, but also can operate in two different operation modes, namely vernier machine mode and permanent magnet synchronous motor mode, according to the change in pole number.

On the other hand, in order to improve the difficulty of controlling the pole change of the PCVM, a consequent pole changing vernier machine (CPCVM) has been proposed. The CPCVM is a model in which consequent poles are applied to the existing PCVM, and has a shape in which half of the LCF PM and HCF PM are replaced with an iron core. As a result, the distance between the poles increases due to the replaced iron core, and the pole conversion becomes easy.

However, in the case of the conventional CPCVM, since LCF PMs with different poles are continuously arranged, it is difficult to independently control the magnetization direction of these complementary LCF PMs. There was a problem that occurred.

One technical problem to be solved by the present invention is to provide an energy conversion device that can easily control polarity conversion.

Another technical problem to be solved by the present invention is to provide an energy conversion device that can be switched to four operating modes.

The technical problem to be solved by the present invention is not limited to the above.

In order to solve the above technical problem, the present invention provides an energy conversion device.

According to an embodiment, the energy conversion device may include a stator including stator teeth arranged in a circumferential direction from an outer diameter side and armature windings provided on the stator teeth; and a consequent pole provided on a radially outer side of the stator and formed by alternately arranging a first permanent magnet, a metal pole, and a second permanent magnet having a relatively lower coercive force than the first permanent magnet in a circumferential direction. It may include a rotor having an inner diameter side.

According to one embodiment, the operation mode is switched to any one of the vernier machine mode and the permanent magnet synchronous motor mode. When operated in the vernier machine mode, the first permanent magnet and the second permanent magnet have the same magnetization direction. , When the magnetization direction of the second permanent magnet is changed to the opposite direction, the vernier machine mode may be switched to the permanent magnet synchronous motor mode.

According to an embodiment, the vernier machine mode may be further converted into a flux enhancing mode, and the permanent magnet synchronous motor mode may be further converted into a flux weakening mode.

According to an embodiment, the stator may further include a DC magnetization coil enabling a demagnetization of the second permanent magnet.

According to an embodiment, the vernier machine mode may be switched to the magnetic flux enhancement mode by increasing magnetic flux according to a current value of the DC magnetizing coil.

According to an embodiment, the permanent magnet synchronous motor mode may be switched to the magnetic flux weakening mode by reducing magnetic flux according to a current value of the DC magnetizing coil.

According to an embodiment, the DC magnetization coil may be provided at a front end side of the stator tooth in a direction facing the consequent pole.

According to an embodiment, a mounting groove portion into which the DC magnetizing coil is mounted is provided on a front end surface of the stator tooth, the mounting groove portion is provided in a form in which the front end of the stator tooth is bifurcated, and the stator tooth is the mounting groove portion. It can be provided as a modulation pole by

According to an embodiment, an upper surface of the DC magnetization coil mounted in the mounting groove part and a front end surface of the stator tooth may form a flat surface without a step.

According to one embodiment, the second permanent magnet may have a relatively larger volume than the first permanent magnet.

According to one embodiment, the metal pole may have a relatively narrower width than that of the first permanent magnet or the second permanent magnet.

According to one embodiment, the metal pole may be made of a metal material containing iron.

According to an embodiment of the present invention, the stator including stator teeth (teeth) arranged in the circumferential direction from the outer diameter side and the armature winding provided on the stator teeth; and a consequent pole provided on a radially outer side of the stator and formed by alternately arranging a first permanent magnet, a metal pole, and a second permanent magnet having a relatively lower coercive force than the first permanent magnet in a circumferential direction. It may include a rotor having an inner diameter side.

Accordingly, an energy conversion device with easy control for polarity conversion can be provided.

In addition, according to an embodiment of the present invention, an energy conversion device that is converted into four operating modes may be provided.

That is, according to an embodiment of the present invention, when operating in the low-speed vernier machine mode, it is further switched to the magnetic flux enhancement mode to increase torque, and when operating in the high-speed permanent magnet synchronous motor mode, it is further switched to the magnetic flux weakening mode , the phase voltage can be reduced to reduce the power consumption or have a higher speed.

In this way, according to an embodiment of the present invention, even if the vernier machine mode and the permanent magnet synchronous motor mode are implemented, an energy conversion device capable of providing excellent performance suitable for the purpose of use can be provided through a DC magnetization coil. there is.

In addition, according to an embodiment of the present invention, the amount of permanent magnets used is reduced, thereby reducing manufacturing costs.

1 is a schematic cross-sectional view showing an energy conversion device according to an embodiment of the present invention.
FIG. 2 is an enlarged view showing an enlarged portion "A" in FIG. 1 .
3 is a reference diagram for explaining a vernier machine mode of an energy conversion device according to an embodiment of the present invention.
4 is a reference diagram for explaining a permanent magnet synchronous motor mode of an energy conversion device according to an embodiment of the present invention.
5 is a magnetic equivalent circuit when the energy conversion device according to an embodiment of the present invention operates in a magnetic flux enhancement mode.
6 is a graph showing a comparison of changes in flux linkage depending on whether or not a DC magnetizing coil is used in the magnetic flux enhancement mode of the energy conversion device according to an embodiment of the present invention.
7 is a graph showing a comparison of torque change according to whether a DC magnetizing coil is used in the magnetic flux enhancement mode of the energy conversion device according to an embodiment of the present invention.
8 is a magnetic equivalent circuit when the energy conversion device according to an embodiment of the present invention operates in a magnetic flux weakening mode.
9 is a graph showing a comparison of changes in flux linkage according to whether or not a DC magnetizing coil is used in the magnetic flux weakening mode of the energy conversion device according to an embodiment of the present invention.
10 is a graph illustrating a comparison of phase voltage changes depending on whether or not a DC magnetizing coil is used in a magnetic flux weakening mode of an energy conversion device according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete, and the spirit of the present invention will be sufficiently conveyed to those skilled in the art.

In this specification, when an element is referred to as being on another element, it means that it may be directly formed on the other element or a third element may be interposed therebetween. Also, in the drawings, shapes and sizes are exaggerated for effective description of technical content.

In addition, although terms such as first, second, and third are used to describe various elements in various embodiments of the present specification, these elements should not be limited by these terms. These terms are only used to distinguish one component from another. Therefore, what is referred to as a first element in one embodiment may be referred to as a second element in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiments. In addition, in this specification, 'and/or' is used to mean including at least one of the elements listed before and after.

In the specification, expressions in the singular number include plural expressions unless the context clearly dictates otherwise. In addition, the terms "comprise" or "having" are intended to designate that the features, numbers, steps, components, or combinations thereof described in the specification exist, but one or more other features, numbers, steps, or components. It should not be construed as excluding the possibility of the presence or addition of elements or combinations thereof. In addition, in this specification, "connection" is used to mean both indirectly and directly connecting a plurality of components.

In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

1 is a schematic cross-sectional view showing an energy conversion device according to an embodiment of the present invention, FIG. 2 is an enlarged view showing an enlarged portion “A” in FIG. 1, and FIG. 3 is an energy conversion device according to an embodiment of the present invention. It is a reference diagram for explaining the vernier machine mode of the conversion device, and FIG. 4 is a reference diagram for explaining the permanent magnet synchronous motor mode of the energy conversion device according to an embodiment of the present invention.

As shown in FIGS. 1 and 2 , the energy conversion device 100 according to an embodiment of the present invention may include a stator 110 and a rotor 120 .

The stator 110 may be provided on one side of the rotor 120 . The stator 110 may be provided inside the rotor 120 in the radial direction. To this end, the stator 110 may be provided in a cylindrical shape having an outer diameter smaller than the inner diameter of the rotor 120 .

According to an embodiment of the present invention, the stator 110 may include stator teeth 111. A plurality of stator teeth 111 may be provided and arranged in a circumferential direction on the outer diameter side of the stator 110 . At this time, the stator teeth 111 adjacent to each other may be defined as stator slots.

At this time, according to an embodiment of the present invention, the stator tooth 111 may be provided as a modulation pole. The modulation pole may be formed in a form in which the front end of the stator tooth 111 is branched into both branches. In this way, as the front end of the stator tooth 111 is provided with a modulation pole branching into both branches, the total number of slots can be increased.

According to an embodiment of the present invention, as the front end of the stator tooth 111 is provided as a modulation pole, the slot between the bifurcated parts may be defined as the mounting groove 111a.

The mounting groove 111a may provide a mounting space for a DC magnetization coil 113 to be described later. In this case, the depth of the mounting groove 111a may be the same as the thickness of the DC magnetization coil 113 mounted thereon.

Accordingly, when the DC magnetization coil 113 is mounted in the mounting groove 111a, the upper surface of the DC magnetization coil 113 and the front end surface of the stator tooth 111 can form a flat surface without a step.

The stator 110 may further include an armature winding 112 . The armature winding 112 may generate a stator field, that is, a magnetic field for rotating the rotor 120 to rotate. These armature windings 112 may be provided on each stator tooth 112.

The armature winding 112 may be grouped according to the phase of the applied current.

For example, when three phases of A, B, and C having two pole pairs are applied to the armature winding 112, the armature winding 112 includes first armature windings A+ and A-, and second armature windings. It may be grouped into windings B+ and B- and third armature windings C+ and C-.

At this time, a heterogeneous group of armature windings 112 may be formed in a specific stator tooth 111 . Also, the same group of armature windings 112 may be formed on a specific stator tooth 111 .

Meanwhile, according to an embodiment of the present invention, the stator 110 may further include a DC magnetizing coil 113.

The DC magnetization coil 113 may be provided at the front end side of the stator teeth 111 in a direction facing the consequent pole provided on the rotor 120 .

According to an embodiment of the present invention, the DC magnetization coil 113 may be mounted in the mounting groove 111a provided on the front end surface of the stator tooth 111 .

In this way, the DC magnetization coil 113 mounted in the mounting groove 111a can form a flat surface without a step with the front end surface of the fixed difference tooth 111 .

According to an embodiment of the present invention, the DC magnetization coil 113 may enable the demagnetization of the second permanent magnet 122 to be described later.

Accordingly, the magnetization direction of the second permanent magnet 122 may be changed.

The energy conversion device 100 according to an embodiment of the present invention is equipped with such a DC magnetizing coil 113, thereby avoiding the conventional complex three-phase AC current control, and the DC pulse current in the DC magnetizing coil 113. , the polarity of the second permanent magnet 122 made of a permanent magnet (LCF PM) having a low coercive force may be performed.

In the energy conversion device 100 according to an embodiment of the present invention, the direction of magnetization of the second permanent magnet 122 is changed by the DC magnetization coil 113, so that any one of the vernier machine mode and the permanent magnet synchronous motor mode is selected. It can be switched to operating mode and operated.

That is, the energy conversion device 100 according to an embodiment of the present invention may optimize or improve performance for each operation mode by including the DC magnetization coil 113 .

At this time, the stator tooth 111 structurally, more specifically, the DC magnetization coil 113 mounted in the mounting groove 111a provided at the front end of the stator tooth 111 is a second permanent magnet flowing through the stator tooth 111. Decrease or increase the magnetic flux of (122).

Through this, the energy conversion device 100 according to an embodiment of the present invention can easily switch from a vernier machine mode to a flux enhancing mode described later, and from a permanent magnet synchronous motor mode to a flux weakening mode described later. (Flux Weakening mode), which will be described in more detail below.

The rotor 120 may rotate with respect to the stator 110 by the generated rotor field and the stator field generated by the stator 110 .

According to one embodiment of the present invention, such a rotor 120 may be provided on one side of the stator 110. The rotor 120 may be provided outside the stator 110 in a radial direction.

The rotor 120 may have a cylindrical shape with a hollow inside. In this case, the inner diameter of the rotor 120 may be larger than the outer diameter of the stator 110 .

Accordingly, the stator 110 may be inserted into the hollow formed inside the rotor 120 .

According to an embodiment of the present invention, the rotor 120 may include a consequent pole. Specifically, the rotor 120 may have the consequent pole on an inner diameter side facing the stator 110 .

The consequent pole may be formed by alternately arranging the first permanent magnet 121, the metal pole 123, and the second permanent magnet 122 in the circumferential direction.

According to an embodiment of the present invention, the first permanent magnet 121 may include a high coercive force permanent magnet (HCF PM) having a high coercive force.

For example, the first permanent magnet 121 may be made of a permanent magnet containing Nd-Fe-B components.

At this time, according to an embodiment of the present invention, the first permanent magnet 121 made of a permanent magnet (HCF PM) having a high coercive force, and a permanent magnet (Low Coercive Force Permanent Magnet (LCF PM) having a relatively low coercive force) In order to reduce the coupling effect between the second permanent magnets 122 made of ), the first permanent magnet 121 and the second permanent magnet 122 may be provided with different sizes.

According to one embodiment of the present invention, the first permanent magnet 121 may have a relatively smaller volume than the second permanent magnet 122 .

For example, the first permanent magnet 121 may have the same width as the second permanent magnet 122 and may have a relatively smaller thickness than the second permanent magnet 122 .

Also, according to an embodiment of the present invention, the width of the first permanent magnet 121 may have a relatively wider width than that of the metal pole 123 . For example, the width of the first permanent magnet 121 may be twice the width of the metal pole 123 .

The metal pole 123 may be provided between the first permanent magnet 121 and the second permanent magnet 122 . Both ends of the metal pole 123 in the width direction may be in close contact with the first permanent magnet 121 and the second permanent magnet 122 , respectively.

That is, according to an embodiment of the present invention, the plurality of first permanent magnets 121, the plurality of metal poles 123, and the plurality of second permanent magnets 122 are in close contact with each other in the circumferential direction to form consequent poles. can

Meanwhile, the metal pole 123 may have a relatively smaller width than the widths of the first permanent magnet 121 and the second permanent magnet 122 having the same width. For example, the width of the metal pole 123 may be 1/2 of the width of the first permanent magnet 121 .

According to one embodiment of the present invention, the metal pole 123 may be made of a metal material. For example, the metal pole 123 may be made of a metal material including iron.

In this way, according to an embodiment of the present invention, one pole of an existing permanent magnet may have a shape in which a metal pole 123 serving as an iron core is replaced.

Since one existing pole is removed in this way, the distance between the first permanent magnet 121 and the second permanent magnet 122 becomes farther, and through this, the magnetization direction of the second permanent magnet 122 for pole conversion is changed. can be unified. This means that the control for the polarity change becomes easy, and the control for the polarity change will be described in more detail below.

At this time, according to an embodiment of the present invention, the rotor 120 has a salient pole shape by the metal pole 123, and through this, reluctance torque can be additionally obtained.

However, this increases the cost-to-torque characteristics but has a lower torque than when the consequent pole is not applied.

The energy conversion device 100 according to an embodiment of the present invention includes a DC magnetizing coil 113 to compensate for this disadvantage, and two teeth split from one stator tooth 111 to utilize space for this. It is to have a modulation pole in the form of coming out.

The second permanent magnet 122 may be provided as a low coercive force permanent magnet (LCF PM) having a relatively lower coercive force than the first permanent magnet 121 .

For example, the second permanent magnet 122 may be made of a permanent magnet based on AlNiCo.

At this time, as described above, the second permanent magnet 122 may have a different size from the first permanent magnet 121 in order to reduce a coupling effect with the first permanent magnet 121 .

Accordingly, according to an embodiment of the present invention, the second permanent magnet 122 may have a relatively larger volume than the first permanent magnet 121 .

For example, the second permanent magnet 122 may have the same width as the first permanent magnet 121 and may have a relatively thicker thickness than the first permanent magnet 121 .

Also, according to an embodiment of the present invention, the width of the second permanent magnet 122 may have a relatively wider width than that of the metal pole 123 . For example, the width of the second permanent magnet 122 may be twice the width of the metal pole 123 .

As such, the stator 110 including the DC magnetization coil 113 and the rotor 120 including the consequent poles composed of the first permanent magnet 121, the metal pole 123, and the second permanent magnet 121 ), the energy conversion device 100 according to an embodiment of the present invention includes any one of a Vernier machine mode (VM mode) and a permanent magnet synchronous machine mode (PMSM mode) can be switched to the operating mode of

Hereinafter, the vernier machine mode and the permanent magnet synchronous motor mode, which are operating modes of the energy conversion device according to an embodiment of the present invention, will be described with reference to FIGS. 3 and 4 .

3 is a reference diagram for explaining a vernier machine mode of an energy conversion device according to an embodiment of the present invention.

Referring to FIG. 3 , when the energy conversion device 100 according to an embodiment of the present invention operates in the vernier machine mode, the second permanent magnet 122 is formed by the DC magnetization coil 113, and the first permanent magnet It may have the same magnetization direction as (121).

At this time, the metal pole 123 made of an iron core applied to the consequent pole serves as a permanent magnet. Accordingly, the magnetic flux curve may flow in the consequent pole portion.

Accordingly, the energy conversion device 100 according to an embodiment of the present invention satisfies the design condition of the vernier machine mode defined by Equation 1 below and can operate in the corresponding mode.

[Equation 1]

±Z _r = Z _s - p

Here, Z _r , Z _s and p are the number of pole pairs of the rotor 120, the number of pole pairs of the stator 110, and the number of pole pairs of the armature winding 112, respectively. At this time, each design value is Z _r = 24, Z _s = 36 and p = 12.

4 is a reference diagram for explaining the permanent magnet synchronous motor mode of the energy conversion device according to an embodiment of the present invention.

Referring to FIG. 4 , when the energy conversion device 100 according to an embodiment of the present invention operates in the permanent magnet synchronous motor mode, the second permanent magnet 122 is driven by the DC magnetization coil 113, It may have a magnetization direction opposite to that of the permanent magnet 121 . At this time, all the second permanent magnets 122 may have the same magnetization direction.

That is, according to an embodiment of the present invention, DC current is applied to the DC magnetization coil 113 to change the magnetization direction of the second permanent magnet 122 to a direction opposite to the magnetization direction in the vernier machine mode. If so, the energy conversion device 100 can be easily switched from the vernier machine mode to the permanent magnet synchronous motor mode.

The energy conversion device 100 according to an embodiment of the present invention satisfies the design condition of the permanent magnet synchronous motor mode defined by Equation 2 below and can operate in the corresponding mode.

[Equation 2]

Z _r = p

Here, when the polarity is changed by changing the magnetization direction of the second permanent magnet 122 , Z _r becomes 12, which is the same as the number of pole pairs of the armature winding 112 12 .

Hereinafter, a magnetic flux enhancement mode and a magnetic flux weakening mode, which are operating modes of an energy conversion device according to an embodiment of the present invention, will be described with reference to FIGS. 5 to 10 .

According to an embodiment of the present invention, the vernier machine mode may be further converted to a flux enhancing mode.

5 is a magnetic equivalent circuit when the energy conversion device according to an embodiment of the present invention operates in a magnetic flux enhancement mode.

Referring to FIG. 5 , in the magnetic flux enhancement mode, the magnetic flux may be increased by allowing a DC current to flow in the DC magnetizing coil 113 according to the magnetic flux flow according to the magnetic flux curve in the vernier machine mode. Accordingly, higher torque can be obtained.

However, as a high current flows through the DC magnetizing coil 113, the magnetic flux density increases, and accordingly, magnetic flux saturation occurs in the stator teeth 111 and the modulation pole portion of the stator 110, which may reduce performance.

Therefore, ideal current values of the three-phase AC current for driving and the DC current for magnetic flux enhancement should flow to the DC magnetizing coil 113 in consideration of the average torque and the like.

Here, F _Hm and R _Hm shown in the magnetic equivalent circuit of FIG. 5 are the magnetomotive force and magnetic resistance of the first permanent magnet 121, respectively, and F _Lm and R _Lm are the magnetomotive force of the second permanent magnet 122 and It is a magnetic equivalent circuit, and R _r , R _s , and R _g are the magnetic resistances of the rotor 120, the stator 110, and the air gap, respectively.

6 is a graph showing a comparison of changes in flux linkage depending on whether or not a DC magnetizing coil is used in the magnetic flux enhancement mode of the energy conversion device according to an embodiment of the present invention.

Referring to FIG. 6 , it can be seen that in the magnetic flux enhancement mode, the flux linkage increases only in a certain section. When the strengthening current is applied, the magnetic flux of the energy conversion device 100 increases, but the increased magnetic flux demagnetizes the second permanent magnet 122 made of LCF PM.

When the magnetic flux due to the magnetic flux enhancement current is directed to the rotor 120, a large demagnetization effect of the second permanent magnet 122 is generated, and a small demagnetization effect is generated when the magnetic flux flows toward the inside of the stator 110. This causes a situation in which performance is rather reduced due to demagnetization of the second permanent magnet 122 even when a magnetic flux enhancing current is applied.

In order to prevent such performance deterioration, magnetic flux enhancement current is temporarily applied to the inner direction of the stator 120 having the least demagnetization effect on the second permanent magnet 122, thereby minimizing the demagnetization of the second permanent magnet 122 while minimizing performance. will increase However, in this method, performance of the energy conversion device 100 is not significantly increased.

Here, flux linkage means the sum of magnetic flux passing through the armature winding 112, and inductance means magnetic flux linkage per unit current. Inductance is divided into self-inductance and mutual-inductance. Self-inductance refers to the amount of magnetic flux generated by directly passing through a coil. It means the amount of magnetic flux linkage.

For reference, the solid line in the graph shown in FIG. 6 is the flux linkage without using the DC magnetizing coil 113, and the dotted line in the graph is the flux linkage when the DC magnetizing coil 113 is used.

7 is a graph showing a comparison of torque change according to whether a DC magnetizing coil is used in the magnetic flux enhancement mode of the energy conversion device according to an embodiment of the present invention.

Referring to FIG. 7 , the solid line in the graph is the torque change when the DC magnetizing coil 113 is not used, that is, when the magnetic flux enhancement current is not applied, and the dotted line in the graph is the torque change when the DC magnetizing coil 113 is used, that is, , is the torque change when applying the magnetic flux enhancing current.

It can be seen that in the magnetic flux enhancing mode, when a magnetic flux enhancing current is applied, the torque increases according to the increased flux linkage. At this time, the torque may increase according to the applied magnetic flux enhancement current, and may rather decrease when a specific current is reached.

For example, the torque may increase when a flux enhancement current of 1A to 3A flows, but may rather decrease from 4A.

On the other hand, all devices use an inverter for driving, and there are limitations in speed and performance depending on the size and performance of the inverter. That is, as the value of the phase voltage is lowered, limitations in speed and performance due to the inverter can be avoided.

Accordingly, according to an embodiment of the present invention, the permanent magnet synchronous motor mode may be further converted into a flux weakening mode.

8 is a magnetic equivalent circuit for a case where the energy conversion device according to an embodiment of the present invention operates in a magnetic flux weakening mode.

Referring to FIG. 8 , in the magnetic flux weakening mode, the magnetic flux may be reduced by flowing a DC current that opposes the flow of magnetic flux to the DC magnetizing coil 113 according to the magnetic flux curve in the permanent flux synchronous motor mode. Accordingly, counter electromotive force and torque values are reduced compared to the permanent magnet synchronous motor mode.

In the permanent magnet synchronous motor mode for high-speed operation, there is a problem that the inverter is limited due to high phase voltage. In the flux weakening mode, the phase voltage can be lowered by lowering the magnetic flux, and thus, problems in the inverter can be avoided and a wider speed range can be obtained.

Here, F _Hm and R _Hm shown in the magnetic equivalent circuit of FIG. 8 are the magnetomotive force and magnetic resistance of the first permanent magnet 121, respectively, and F _Lm and R _Lm are the magnetomotive force of the second permanent magnet 122 and It is a magnetic equivalent circuit, and R _r , R _s , and R _g are the magnetic resistances of the rotor 120, the stator 110, and the air gap, respectively.

9 is a graph showing a comparison of flux linkage changes depending on whether or not a DC magnetizing coil is used in a magnetic flux weakening mode of an energy conversion device according to an embodiment of the present invention, and FIG. 10 is an energy conversion device according to an embodiment of the present invention It is a graph showing the phase voltage change according to whether DC magnetizing coil is used or not in the magnetic flux weakening mode.

Here, the solid line in the graph shown in FIG. 9 represents the change in flux linkage when the DC magnetizing coil is not used, and the dotted line represents the change in flux linkage when the DC magnetization coil is used.

In the graph shown in FIG. 10 , a solid line indicates a phase voltage change when a DC magnetizing coil is not used, and a dotted line indicates a phase voltage change when a DC magnetizing coil is used.

Referring to FIGS. 9 and 10 , it can be seen that the phase voltage is reduced by about 32.5% in the flux weakening mode according to the reduced flux linkage. This means that power consumption can be lowered or operated at high speed when using the same commercial inverter.

As described above, according to an embodiment of the present invention, the energy conversion device 100 that can be easily controlled for polarity conversion can be provided.

That is, since the energy conversion device 100 according to an embodiment of the present invention includes the DC magnetizing coil 113, it can be easily switched to a total of four operating modes.

The energy conversion device 100 may further switch from the permanent magnet synchronous motor mode to the magnetic flux weakening mode, and through this, the magnetic flux can be easily reduced according to the DC current value, which lowers the capacity of the inverter by lowering the phase voltage or It has a wider speed range.

In addition, the energy conversion device 100 may further switch from the vernier machine mode to the magnetic flux enhancement mode, and thus, the magnetic flux may be further increased to obtain higher torque.

That is, according to an embodiment of the present invention, the energy conversion device 100 capable of providing excellent performance suitable for the purpose of use can be provided through the above four operating modes.

In the above, the present invention has been described in detail using preferred embodiments, but the scope of the present invention is not limited to specific embodiments, and should be interpreted according to the appended claims. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

100; energy conversion device
110; stator
111; stator teeth
111a; mounting groove
112; armature winding
113; DC magnetizing coil
120; rotor
121; First permanent magnet
122; Second permanent magnet
123; metal pole

Claims (12)

a stator including stator teeth arranged in a circumferential direction from an outer diameter side and armature windings provided on the stator teeth; and
A consequent pole provided on the outer side of the stator in the radial direction and formed by alternately arranging a first permanent magnet, a metal pole, and a second permanent magnet having a relatively lower coercive force than the first permanent magnet in a circumferential direction A rotor provided on the inner diameter side; including, an energy conversion device.
According to claim 1,
Converted to one of the operating modes of vernier machine mode and permanent magnet synchronous motor mode,
When operating in the vernier machine mode, the first permanent magnet and the second permanent magnet have the same magnetization direction,
When the magnetization direction of the second permanent magnet is changed to the opposite direction, the vernier machine mode is switched to the permanent magnet synchronous motor mode.
According to claim 2,
The vernier machine mode is further converted to a flux enhancing mode (Flux Enhancing mode), and the permanent magnet synchronous motor mode is further converted to a flux weakening mode (Flux Weakening mode).
According to claim 3,
The energy conversion device of claim 1, wherein the stator further includes a DC magnetization coil enabling demagnetization of the second permanent magnet.
According to claim 4,
The energy conversion device, wherein the vernier machine mode is switched to the magnetic flux enhancement mode by increasing magnetic flux according to the current value of the DC magnetizing coil.
According to claim 4,
The permanent magnet synchronous motor mode is converted to the magnetic flux weakening mode by reducing magnetic flux according to the current value of the DC magnetizing coil.
According to claim 4,
The energy conversion device of claim 1 , wherein the DC magnetizing coil is provided at a front end side of the stator teeth in a direction facing the consequent poles.
According to claim 7,
A mounting groove in which the DC magnetizing coil is mounted is provided on the front end surface of the stator tooth,
The energy conversion device of claim 1 , wherein the mounting groove portion is provided in a form in which the tip of the stator tooth is bifurcated, and the stator tooth is provided as a modulation pole by the mounting groove portion.
According to claim 8,
The energy conversion device of claim 1 , wherein an upper surface of the DC magnetization coil mounted in the mounting groove part and a front end surface of the stator teeth form a flat surface without a step difference.
According to claim 1,
The second permanent magnet has a relatively larger volume than the first permanent magnet.
According to claim 1,
The energy conversion device, wherein the metal pole has a relatively narrower width than that of the first permanent magnet or the second permanent magnet.
According to claim 1,
The metal pole is made of a metal material containing iron (iron), energy conversion device.

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