Control system for permanent magnet rotating electric machine and control method for permanent magnet rotating electric machine

Abstract

The purpose of the present invention is to drive a permanent magnet rotating electrical machine provided with an eddy current suppression member under control conditions capable of suppressing eddy current loss of the entire rotor. A drive system (3) for a permanent magnet rotating electrical machine is provided with: a permanent magnet rotating electrical machine (1) provided with a stator having a stator core and a stator coil (12), and a rotor having a rotor core, a plurality of permanent magnets, and an eddy current suppression member; an inverter (30); and a control device (31) that specifies a carrier frequency that is greater than a cross-loss frequency that is calculated on the basis of mathematical expressions using the dimensions and physical constants of the permanent magnets and the eddy current suppression members.

Description

Technical Field

[0001] The present application relates to a control system of a permanent magnet rotating electric machine and a control method of the permanent magnet rotating electric machine. Background Art

[0002] In a permanent magnet type rotating electric machine having a permanent magnet in a rotor, an eddy current flows in the permanent magnet during a rotating motion. When an eddy current flows in the permanent magnet, an increase in resistance caused by the eddy current and demagnetization associated with a temperature rise of the permanent magnet occur, resulting in power loss called eddy current loss. As a conventional rotating electric machine capable of suppressing eddy currents flowing in permanent magnets, a structure is disclosed in which a highly conductive eddy current suppression component is arranged on the periphery of the permanent magnet (for example, see patent document 1).

[0003] Prior art literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2002-345189 Summary of the invention

[0005] However, in a conventional rotating electrical machine in which an eddy current suppression member is arranged on the periphery of a permanent magnet, eddy current also flows in the eddy current suppression member, so there is a problem that eddy current loss including the permanent magnet and the eddy current suppression member increases depending on control conditions.

[0006] The present application is made to solve the above-mentioned problems, and its object is to drive the permanent magnet rotating electric machine under control conditions capable of suppressing eddy current losses including permanent magnets and the eddy current suppressing component in a driving system of the permanent magnet rotating electric machine having the eddy current suppressing component.

[0007] The drive system of the permanent magnet rotating electric machine of the present application comprises: a permanent magnet rotating electric machine, comprising a stator and a rotor, wherein the stator has a stator core in a ring shape and a stator coil wound on the stator core, and the rotor has a rotor core connected to a rotating shaft and a plurality of permanent magnets embedded in the rotor core; an inverter, which outputs driving power to the stator coil; and a control device, which controls the output of the inverter by specifying a carrier frequency to the inverter. A plurality of permanent magnets are arranged in a circumferential direction, and at least one of the permanent magnets has an eddy current suppression component arranged on a magnetic flux generating surface through an insulating component, and in a cross section of a surface orthogonal to the rotating shaft, the length of the magnetic flux generating surface of one permanent magnet in the longitudinal direction is set as the width d 1 , let the length of the magnetic flux generating surface in the depth direction be h 1 , let the conductivity of a permanent magnet be σ 1 , set the magnetic permeability to μ 1 , the length of the surface of the eddy current suppression component facing one permanent magnet in the longitudinal direction is defined as the width d 2, let the length of the surface facing one permanent magnet in the depth direction be h 2 , let the conductivity of the eddy current suppression component be σ 2 , set the magnetic permeability to μ 2 When , the control device specifies a carrier frequency greater than the frequency f calculated according to the following 7 equations,

[0008] [Mathematical formula 1]

[0009]

[0010] [Mathematical formula 2]

[0011]

[0012] [Mathematical formula 3]

[0013]

[0014] [Formula 4]

[0015]

[0016] [Mathematical formula 5]

[0017]

[0018] [Mathematical formula 6]

[0019]

[0020] [Mathematical formula 7]

[0021]

[0022] In the permanent magnet rotating electrical machine drive system of the present application, the control device specifies a carrier frequency greater than the frequency f calculated according to the above 7 equations, so that the permanent magnet rotating electrical machine can be driven under control conditions that can suppress eddy current losses including permanent magnets and eddy current suppression components. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a cross-sectional view of the permanent magnet rotating electrical machine according to the first embodiment.

[0024] Figure 2 It is an enlarged cross-sectional view of the rotor of the permanent magnet rotating electrical machine according to the first embodiment.

[0025] Figure 3 It is a configuration diagram of a drive system of a permanent magnet rotating electrical machine according to the first embodiment.

[0026] Figure 4This is a characteristic diagram of eddy current loss in the permanent magnet rotating electrical machine according to the first embodiment.

[0027] Figure 5 This is a characteristic diagram showing an example of the relationship between the loss crossover frequency and the width of the permanent magnet in the permanent magnet type rotating electrical machine according to the first embodiment.

[0028] Figure 6 It is an enlarged cross-sectional view of a rotor of another permanent magnet rotating electrical machine according to the first embodiment.

[0029] Figure 7 It is an enlarged cross-sectional view of a rotor of a permanent magnet rotating electrical machine according to the second embodiment.

[0030] Figure 8 It is an enlarged cross-sectional view of a rotor of a permanent magnet rotating electrical machine according to the third embodiment.

[0031] Fig. 9 It is an enlarged cross-sectional view of a rotor of a permanent magnet rotating electrical machine according to a fourth embodiment.

[0032] Fig.10 This is a diagram showing a hardware configuration of a control device that realizes a drive system for a permanent magnet rotating electrical machine according to the first to fourth embodiments. DETAILED DESCRIPTION

[0033] Hereinafter, a drive system of a permanent magnet rotating electrical machine according to an embodiment of the present application will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals in each figure represent the same or corresponding parts.

[0034] Implementation method 1.

[0035] Figure 1 It is a cross-sectional view of the permanent magnet rotating electrical machine according to the first embodiment. Figure 1 This is a cross-sectional view in a direction perpendicular to the rotating shaft of the permanent magnet rotating electric machine. The permanent magnet rotating electric machine 1 of this embodiment includes a rotor 20 connected to the rotating shaft 2, and a cylindrical stator 10 coaxially arranged on the outer peripheral side of the rotor 20. A gap G is formed between the rotor 20 and the stator 10. The stator 10 is held in a cylindrical frame not shown. The rotating shaft 2 is supported by a pair of brackets not shown via bearings. The pair of brackets are fixed to both ends of the axial direction of the frame.

[0036] Here, the direction parallel to the axis of the rotating shaft 2 is called an axial direction, the direction orthogonal to the axis of the rotating shaft 2 is called a radial direction, and the direction in which the rotor 20 rotates around the axis of the rotating shaft 2 is called a circumferential direction.

[0037] The stator 10 has a ring-shaped stator core 11 and a stator coil 12 wound on the stator core 11. The stator core 11 has a ring-shaped core back 13 and a plurality of teeth 14 protruding radially inward from the inner circumferential surface of the core back 13. There are 48 teeth 14 arranged at equal intervals in the circumferential direction. The stator coil 12 is wound on the stator core 11 in a distributed winding manner across the plurality of teeth 14.

[0038] The rotor 20 includes a rotor core 21 having a rotating shaft insertion hole into which the rotating shaft 2 is inserted, and 32 permanent magnets 22 embedded in the rotor core 21. The rotor core 21 is connected to the rotating shaft 2 inserted into the rotating shaft insertion hole. Figure 1 In FIG. 1 , the arrows indicated by the permanent magnets 22 indicate the directions of the magnetic fluxes generated by the permanent magnets 22. For example, the stator core 11 and the rotor core 21 are formed by laminating electromagnetic steel sheets in the axial direction.

[0039] Figure 2 This is an enlarged cross-sectional view of one magnetic pole of the rotor of the permanent magnet rotating electrical machine according to the present embodiment. Figure 2 It is a cross-sectional view in a direction perpendicular to the rotation axis of the permanent magnet type rotating electrical machine. In the rotor 20 of the present embodiment, one magnetic pole is composed of four permanent magnets 22. One magnetic pole is a two-layer structure formed by arranging two permanent magnets 22 in a group in a V shape. In the two permanent magnets 22 arranged in a V shape, the permanent magnets 22 on the outer peripheral side are called the first layer, and the permanent magnets 22 on the inner peripheral side are called the second layer. At both ends of the permanent magnets 22, flux barriers 23 having a lower magnetic permeability than the rotor core 21 are formed. In the permanent magnet type rotating electrical machine 1 of the present embodiment, the flux barriers 23 are composed of through holes that penetrate the rotor core 21 in the axial direction. In the permanent magnet type rotating electrical machine 1 of the present embodiment, the flux barriers 23 are formed as a part of a magnet receiving hole that can receive the permanent magnets 22 and the like.

[0040] like Figure 2 As shown, an eddy current suppression component 25 is arranged on the inner circumference side of the magnetic flux generating surface of the second layer of permanent magnets 22 via an insulating component 24. The insulating component 24 is made of, for example, an insulating resin. The eddy current suppression component 25 is made of, for example, copper, aluminum, or other material having a greater electrical conductivity than the permanent magnets 22 and the rotor core 21. Figure 2 In the cross-sectional view shown, the length of the magnetic flux generating surface of the permanent magnet 22 in the longitudinal direction is defined as width d, the length in the depth direction of the magnetic flux generating surface is defined as height h, and the length in the axial direction is defined as thickness a. The dimensions of the eddy current suppression member 25 are also defined in the same manner.

[0041] The electrical conductivity of the eddy current suppression component 25 is greater than that of the permanent magnet 22 and the rotor core 21, so the eddy current generated in the rotor 20 is generated most inside the eddy current suppression component 25. The eddy current generated inside the eddy current suppression component 25 can suppress the magnetic field interlinked with the adjacent permanent magnet 22 through its demagnetization field generation effect. Therefore, the eddy current suppression component 25 can suppress the eddy current generated in the permanent magnet 22.

[0042] Figure 3 3 is a structural diagram of a permanent magnet rotating electric machine drive system according to the present embodiment. The permanent magnet rotating electric machine drive system 3 according to the present embodiment is composed of a permanent magnet rotating electric machine 1, an inverter 30, and a control device 31. The inverter 30 is connected to the permanent magnet rotating electric machine 1. The DC power supply 32 is connected to the inverter 30. The DC power supply 32 supplies DC power to the inverter 30. The inverter 30 is controlled by the control device 31. Detection information such as the rotation position of the rotor 20 of the permanent magnet rotating electric machine 1 and the current flowing in the stator coil 12 is input to the control device 31. The control device 31 generates a command voltage based on the input detection information and command values ​​such as the rotation speed and torque, and outputs it to the inverter 30. The inverter 30 performs a switching operation according to the voltage command input from the control device 31. In the inverter 30, the switching operation is determined by PWM (Pulse Width Modulation) control based on the command voltage transmitted from the control device 31 and the carrier frequency of the carrier.

[0043] Next, the reason why the eddy current loss of the permanent magnet can be reduced in the drive system of the permanent magnet type rotating electrical machine according to the present embodiment will be described.

[0044] In the drive system of the permanent magnet rotating electrical machine of the present embodiment, the angular frequency ω and the average magnetic flux density B are 0 When the permanent magnet is excited by the size of the magnet, the eddy current loss P in the permanent magnet is expressed by the following formula (1). a is the thickness of the permanent magnet, d is the width of the permanent magnet, h is the height of the permanent magnet, σ is the electrical conductivity of the permanent magnet, and μ is the magnetic permeability of the permanent magnet. In addition, the eddy current loss in the eddy current suppression component can also be expressed by formula (1).

[0045] [Mathematical formula 8]

[0046]

[0047] Here, δ is given by the following formula (2).

[0048] [Mathematical formula 9]

[0049]

[0050] By setting the average magnetic flux density B 0 The boundary conditions are constant, and the eddy current loss of the permanent magnet 22 and the eddy current loss of the eddy current suppression component 25 can be calculated separately using equations (1) and (2). Although eddy current loss also occurs in the rotor core 21, it is assumed that the magnitude thereof will not be affected by the presence or absence of the eddy current suppression component 25. That is, the difference between the eddy current loss of the permanent magnet 22 when there is no eddy current suppression component 25 and the sum of the eddy current loss of the permanent magnet 22 and the eddy current loss of the eddy current suppression component 25 when there is an eddy current suppression component 25 becomes the difference in the eddy current loss of the entire rotor.

[0051] Figure 4 1 is a characteristic diagram of the eddy current loss of the permanent magnet 22 or the total eddy current loss of the permanent magnet 22 and the eddy current suppression component 25 in the permanent magnet type rotating electrical machine of the present embodiment. The solid line is the total eddy current loss of the permanent magnet 22 and the eddy current suppression component 25 when the eddy current suppression component 25 is present, and the dotted line is the eddy current loss of the permanent magnet 22 when the eddy current suppression component 25 is not present. Figure 4 In the equation (1), the horizontal axis is the frequency, and the vertical axis is the relative value of the eddy current loss. The frequency of the horizontal axis is given by ω / 2π. In equations (1) and (2), when Ampere's circuital law is applied to make the line integral of the surface magnetic field constant, the following can be obtained: Figure 4 The eddy current loss characteristics for frequency are shown. Here, the relative magnetic permeability μ of the permanent magnet 22 is 1.05, the electrical conductivity σ is 747562S / m, the thickness a is 10mm, the width d is 20mm, and the height h is 6mm, and the relative magnetic permeability μ of the eddy current suppression component 25 is 1.0, the electrical conductivity σ is 45978465S / m, the thickness a is 10mm, the width d is 20mm, and the height h is 0.3mm.

[0052] according to Figure 4, at a frequency greater than a specific frequency, the eddy current loss becomes smaller when there is an eddy current suppression component. However, at a frequency less than a specific frequency, the eddy current loss becomes larger when there is an eddy current suppression component. Since the electrical conductivity of the eddy current suppression component is greater than the electrical conductivity of the permanent magnet, the eddy current loss of the component is added when there is an eddy current suppression component in the low-frequency region, so the eddy current loss increases. However, in the high-frequency region, the magnetic flux that interlinks with the eddy current suppression component is suppressed due to the influence of the skin effect, so the eddy current loss of the eddy current suppression component is reduced. As a result, in the high-frequency region, the total eddy current loss of the permanent magnet and the eddy current suppression component in the case of an eddy current suppression component is less than the eddy current loss of the permanent magnet in the case of no eddy current suppression component. In this way, it can be seen that there is a frequency region where the eddy current suppression component can be used to reduce the eddy current loss of the entire rotor. Here, as Figure 4 As shown in FIG. 1 , the frequency at which the curve of the eddy current loss when the eddy current suppression member is present and the curve of the eddy current loss when the eddy current suppression member is not present intersect is referred to as a loss crossover frequency.

[0053] The dimensions and physical constants of the permanent magnet and the eddy current suppression member are defined as follows: In addition, the units are shown in parentheses.

[0054] <Permanent magnet>

[0055] h 1 :Height(m)

[0056] d 1 :Width(m)

[0057] σ 1 :Conductivity(S / m)

[0058] μ 1 : Magnetic permeability (H / m)

[0059] <Eddy current suppression components>

[0060] h 2 :Height(m)

[0061] d 2 :Width(m)

[0062] σ 2 :Conductivity(S / m)

[0063] μ 2 : Magnetic permeability (H / m)

[0064] Here, the following two equations are used to provide μ 1 and μ 2 .μ r1 is the relative magnetic permeability of the permanent magnet, μ r2 is the relative magnetic permeability of the eddy current suppression component, μ0 is the magnetic permeability of vacuum.

[0065] μ 1 =. μ r1 ×μ 0

[0066] μ 2 =. μ r2 ×μ 0

[0067] Set the average magnetic flux density B 0 The boundary condition that the line integral of the surface magnetic field becomes constant is set as follows: 1 、a 2 Sufficiently larger than their width d 1 d 2 The loss crossover frequency f at which the total eddy current loss of the permanent magnet and the eddy current suppression component when the eddy current suppression component is present becomes equal to the eddy current loss of the permanent magnet when the eddy current suppression component is not present can be calculated by the following equations (3) to (6).

[0068] In addition, when n is set to 1, the equations (3) to (5) are calculation equations related to the permanent magnet, and when n is set to 2, they are calculation equations related to the eddy current suppression member.

[0069] [Formula 10]

[0070]

[0071] [Mathematical formula 11]

[0072]

[0073] [Mathematical formula 12]

[0074]

[0075] [Mathematical formula 13]

[0076]

[0077] Figure 5 The calculation of the width d for the permanent magnet using these formulas is shown as follows: 1 The result is the loss crossover frequency f. Figure 5 : is a characteristic diagram showing an example of the relationship between the width of the permanent magnet and the loss crossover frequency in the permanent magnet type rotating electrical machine of the present embodiment. Figure 5 The horizontal axis is the width d of the permanent magnet. 1 , the vertical axis is the loss crossover frequency. In addition, Figure 5 The characteristics shown are set to h 1=0.006m,h 2 =0.0003m,σ 1 =747562S / m, σ 2 =45978465S / m, μ 1 =1.05H / m,μ 2 =1.0H / m, and set it as d 1 and d 2 Calculated to be equal.

[0078] exist Figure 5 In the case of being excited at a frequency higher than the loss crossover frequency determined by the width of the permanent magnet, the eddy current loss of the entire rotor becomes smaller when there is an eddy current suppression component. Figure 5 It can be seen that the loss crossover frequency varies greatly depending on the magnet width of the permanent magnet. The eddy current flowing in the permanent magnet becomes the cause of the temperature rise of the permanent magnet. Therefore, when the temperature rise of the permanent magnet becomes a problem, the carrier frequency in the PWM control can be set to a frequency higher than the loss crossover frequency on the basis of setting the eddy current suppression component. Specifically, Figure 2 In the permanent magnet rotating machine shown in FIG. 1 , the width of the permanent magnets 22 of the first layer is set to 10 mm, and the width of the permanent magnets 22 of the second layer is set to 20 mm. Figure 5 In the embodiment of the present invention, the loss crossover frequency becomes 1.9kHz when the width of the permanent magnet is 20mm. In the case where an eddy current suppression component is provided, if the carrier frequency in the PWM control is set to 1.9kHz or more, the magnet temperature can be reduced compared with the case where the eddy current suppression component is not provided. Here, as a method for measuring the temperature of the permanent magnet, there are a method for directly measuring the temperature of the permanent magnet in the drive, a method for estimating the magnet temperature based on other physical information of the permanent magnet rotating motor, such as the rotation speed and the control elapsed time, etc.

[0079] The drive system of the permanent magnet type rotating electrical machine configured in this manner is driven at a frequency higher than the loss crossover frequency determined by the width of the permanent magnets in the second layer, thereby being able to suppress eddy current losses in the entire rotor.

[0080] In addition, in the permanent magnet type rotating motor of the present embodiment, the eddy current suppression component is only provided in the permanent magnet of the second layer. When the width of the permanent magnet 22 of the second layer is set to 20mm, if the carrier frequency is set to 1.9kHz or more to drive, the eddy current loss in the permanent magnet of the second layer and the eddy current suppression component becomes smaller. However, the permanent magnet of the first layer is in a position close to the gap G, so an eddy current in the low-frequency region is generated due to slot harmonics. The frequency of the eddy current is less than the loss crossover frequency. Therefore, in the permanent magnet of the first layer, the eddy current loss becomes larger when the eddy current suppression component is provided. For such reasons, in the permanent magnet type rotating motor of the present embodiment, an eddy current suppression component is only provided for the permanent magnet of the second layer.

[0081] Figure 6 FIG. 1 is an enlarged cross-sectional view of one magnetic pole of a rotor of another permanent magnet type rotating electrical machine according to the present embodiment. In this permanent magnet type rotating electrical machine, an eddy current suppression member 25 is disposed on the outer peripheral side of the magnetic flux generating surface of the second layer of permanent magnets 22 via an insulating member 24. Figure 2 as well as Figure 6 As shown, in the permanent magnet type rotating electrical machine involved in this embodiment, if the eddy current suppression component 25 is arranged at a position opposite to the magnetic flux generating surface of the permanent magnet 22, the eddy current loss of the entire rotor can be suppressed by driving at a frequency higher than the loss crossover frequency. Therefore, the eddy current suppression component 25 can be arranged on one surface or both surfaces opposite to the magnetic flux generating surface of the permanent magnet 22.

[0082] Implementation method 2.

[0083] Figure 7 1 is an enlarged cross-sectional view of one magnetic pole of the rotor of the permanent magnet rotating electrical machine according to the second embodiment. The structure of the permanent magnet rotating electrical machine according to the present embodiment is the same as that of the permanent magnet rotating electrical machine according to the first embodiment except for the structure of the rotor. In addition, the structure of the drive system of the permanent magnet rotating electrical machine according to the present embodiment is also the same as that of the first embodiment. Figure 3 The structures shown are the same.

[0084] like Figure 7 As shown, in the permanent magnet rotating motor involved in this embodiment, an eddy current suppression component 25 is arranged on the inner circumferential side of the magnetic flux generating surface of the second layer of permanent magnets 22 via an insulating component 24, and an eddy current suppression component 25 is arranged on the inner circumferential side of the magnetic flux generating surface of the first layer of permanent magnets 22 via an insulating component 24.

[0085] In the permanent magnet type rotating electrical machine according to the present embodiment, the width of the second layer of permanent magnets 22 is 20 mm, and the width of the first layer of permanent magnets 22 is 10 mm. Figure 5 The relationship between the loss crossover frequency and the width of the permanent magnet is shown in FIG. 1 , and the loss crossover frequency is 7.7 kHz when the width of the permanent magnet is 10 mm. In this permanent magnet rotating motor, if the carrier frequency in the PWM control is set to 7.7 kHz or more, the eddy current loss of the permanent magnet and the eddy current suppression component of the first layer can be suppressed, and the eddy current loss of the permanent magnet and the eddy current suppression component of the second layer can be suppressed.

[0086] As described above, in the drive system of the permanent magnet rotating electrical machine according to the present embodiment, the eddy current loss of the entire rotor can be suppressed by driving at a frequency higher than the loss crossover frequency determined by the width of the permanent magnets of the first layer.

[0087] Implementation method 3.

[0088] Figure 8 1 is an enlarged cross-sectional view of one magnetic pole of the rotor of the permanent magnet rotating electric machine according to the third embodiment. The structure of the permanent magnet rotating electric machine according to the present embodiment is the same as that of the permanent magnet rotating electric machine according to the first embodiment except for the structure of the rotor. In addition, the structure of the drive system for driving the permanent magnet rotating electric machine according to the present embodiment is also the same as that of the first embodiment. Figure 3 The structures shown are the same.

[0089] like Figure 8 As shown, in the permanent magnet type rotating electrical machine involved in this embodiment, one magnetic pole is composed of six permanent magnets 22. One magnetic pole is a three-layer structure in which two permanent magnets 22 are arranged in a V shape. An eddy current suppression component 25 is arranged on the inner circumference side of the magnetic flux generating surface of the permanent magnet 22 of the third layer through an insulating component 24.

[0090] In the permanent magnet type rotating electrical machine according to the present embodiment, the width of the permanent magnets 22 in the third layer is 20 mm, the width of the permanent magnets 22 in the second layer is 15 mm, and the width of the permanent magnets 22 in the first layer is 10 mm. Figure 5 The relationship between the loss crossover frequency and the width of the permanent magnet is shown in FIG. 1 . The loss crossover frequency is 1.9 kHz when the width of the permanent magnet is 20 mm. In this permanent magnet rotating machine, if the carrier frequency in PWM control is set to 1.9 kHz or more, the eddy current loss of the third layer of permanent magnets and the eddy current suppression component can be suppressed.

[0091] As described above, in the permanent magnet type rotating electrical machine drive system of the present embodiment, the eddy current loss of the entire rotor can be suppressed by driving at a frequency higher than the loss crossover frequency determined by the width of the third layer of permanent magnets.

[0092] In addition, in the permanent magnet rotating electrical machine of the present embodiment, one magnetic pole may also be composed of a multilayer structure of four or more layers in which two permanent magnets are arranged in a V shape. In one magnetic pole composed of a multilayer structure, an eddy current suppression component may be arranged for the permanent magnets of the innermost layer via an insulating component.

[0093] Implementation method 4.

[0094] Fig. 9 1 is an enlarged cross-sectional view of one magnetic pole of the rotor of the permanent magnet rotating electric machine according to the fourth embodiment. The structure of the permanent magnet rotating electric machine according to the present embodiment is the same as that of the permanent magnet rotating electric machine according to the first embodiment except for the structure of the rotor. In addition, the structure of the drive system for driving the permanent magnet rotating electric machine according to the present embodiment is also the same as that of the first embodiment. Figure 3 The structures shown are the same.

[0095] like Fig. 9 As shown, in the permanent magnet type rotating electric machine involved in this embodiment, one magnetic pole is composed of three permanent magnets 22. One magnetic pole includes: one inner circumferential permanent magnet 22 having a magnetic flux generating surface in a direction orthogonal to the radial direction; and two outer circumferential permanent magnets 22 respectively arranged at intervals at both ends of the inner circumferential permanent magnet 22. The two outer circumferential permanent magnets 22 have magnetic flux generating surfaces in the radial direction. An eddy current suppression component 25 is arranged on the inner circumferential side of the magnetic flux generating surface of the inner circumferential permanent magnet 22 via an insulating component 24.

[0096] In the permanent magnet rotating electrical machine according to the present embodiment, the width of the inner circumferential permanent magnet 22 is 20 mm. Figure 5 The relationship between the loss crossover frequency and the width of the permanent magnet is shown in FIG. 1 . The loss crossover frequency is 1.9 kHz when the width of the permanent magnet is 20 mm. In this permanent magnet rotating electric machine, if the carrier frequency in PWM control is set to 1.9 kHz or more, the eddy current loss of the permanent magnet on the inner circumference side and the eddy current suppression component can be suppressed.

[0097] As described above, in the drive system of the permanent magnet rotating electrical machine of the present embodiment, the eddy current loss of the entire rotor can be suppressed by driving at a frequency higher than the loss crossover frequency determined by the width of the permanent magnets on the inner circumference side.

[0098] In addition, as an example of hardware, such as Fig.10As shown, the control device 31 is composed of a processor 100 and a storage device 101. Although the storage device is not shown in the figure, it has a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory. In addition, an auxiliary storage device such as a hard disk may be provided instead of the flash memory. The processor 100 executes a program input from the storage device 101. In this case, the program is input from the auxiliary storage device to the processor 100 via the volatile storage device. In addition, the processor 100 can output data such as calculation results to the volatile storage device of the storage device 101, and can also save the data to the auxiliary storage device via the volatile storage device.

[0099] The present application describes various exemplary embodiments, but various features, methods, and functions described in one or more embodiments are not limited to application in specific embodiments, but can be applied to the embodiments alone or in various combinations.

[0100] Therefore, numerous variations not shown in the examples are conceivable within the scope of the technology disclosed in the present application, such as variations in at least one component, addition of at least one component, or omission of at least one component, and extraction of at least one component and combination with components of other embodiments.

[0101] Explanation of symbols

[0102] 1: permanent magnet rotating motor; 2: rotating shaft; 3: driving system of permanent magnet rotating motor; 10: stator; 11: stator core; 12: stator coil; 13: core back; 14: teeth; 20: rotor; 21: rotor core; 22: permanent magnet; 23: magnetic isolation groove; 24: insulating component; 25: eddy current suppression component; 30: inverter; 31: control device; 32: DC power supply; 100: processor; 101: storage device.

Claims

1. A drive system for a permanent magnet rotating electrical machine, characterized in that: have: A permanent magnet rotating electrical machine comprising a stator and a rotor, wherein the stator has a stator core in a ring shape and a stator coil wound on the stator core, and the rotor has a rotor core connected to a rotating shaft and a plurality of permanent magnets embedded in the rotor core; an inverter, outputting driving power to the stator coil; as well as a control device for controlling the output of the inverter by specifying a carrier frequency to the inverter, In the drive system of the permanent magnet rotating electrical machine, A plurality of the permanent magnets are arranged in a circumferential direction, and at least one of the permanent magnets has an eddy current suppression member disposed on a magnetic flux generating surface via an insulating member. In a cross section taken along a plane perpendicular to the rotation axis, When the length of the magnetic flux generating surface of one of the permanent magnets in the longitudinal direction is set to width d1, the length of the magnetic flux generating surface in the depth direction is set to h1, the electrical conductivity of one of the permanent magnets is set to σ1, the magnetic permeability is set to μ1, the length of the surface of the eddy current suppression component facing one of the permanent magnets in the longitudinal direction is set to width d2, the length of the surface facing one of the permanent magnets in the depth direction is set to h2, the electrical conductivity of the eddy current suppression component is set to σ2, and the magnetic permeability is set to μ2, The control device specifies a carrier frequency greater than the frequency f calculated according to the following seven equations, [Mathematical formula 14] [Mathematical formula 15] [Formula 16] [Mathematical formula 17] [Mathematical formula 18] [Mathematical formula 19] [Mathematical formula 20] 2. The drive system of the permanent magnet rotating electrical machine according to claim 1, characterized in that: The rotor has a plurality of magnetic poles, and one of the magnetic poles is formed of a multilayer structure in which two permanent magnets are arranged in a set in a V shape.

3. The driving system of the permanent magnet rotating electrical machine according to claim 2, characterized in that: In one of the magnetic poles having the multilayer structure, the eddy current suppression member is arranged with respect to the permanent magnet of the innermost layer via the insulating member.

4. The drive system of a permanent magnet rotating electrical machine according to any one of claims 1 to 3, characterized in that: The stator coil wound around the stator core is wound in a distributed winding structure.

5. A method for driving a permanent magnet rotating electrical machine, characterized in that: The permanent magnet type rotating electrical machine includes a stator and a rotor, wherein the stator has a ring-shaped stator core and a stator coil wound around the stator core, and the rotor has a rotor core connected to a rotating shaft and a plurality of permanent magnets embedded in the rotor core. A plurality of the permanent magnets are arranged in a circumferential direction, and at least one of the permanent magnets has an eddy current suppression member disposed on a magnetic flux generating surface via an insulating member. In a cross section taken along a plane perpendicular to the rotation axis, When the length of the magnetic flux generating surface of one of the permanent magnets in the longitudinal direction is set to width d1, the length of the magnetic flux generating surface in the depth direction is set to h1, the electrical conductivity of one of the permanent magnets is set to σ1, the magnetic permeability is set to μ1, the length of the surface of the eddy current suppression component facing one of the permanent magnets in the longitudinal direction is set to width d2, the length of the surface facing one of the permanent magnets in the depth direction is set to h2, the electrical conductivity of the eddy current suppression component is set to σ2, and the magnetic permeability is set to μ2, The stator coil is driven at a carrier frequency greater than the frequency f calculated by the following seven equations. [Mathematical formula 21] [Mathematical formula 22] [Mathematical formula 23] [Mathematical formula 24] [Mathematical formula 25] [Mathematical formula 26] [Mathematical formula 27]

Images