Rotating electrical machines and electric vehicles

Abstract

To provide a rotary electric machine with which it is possible to maintain a prescribed torque even at high revolution time and heighten responsiveness at characteristics switching time.SOLUTION: Provided is a rotary electric machine that includes a permanent magnet, a stator, and a three-phase stator coil in a housing, wherein the stator coil of each phase has three or more coil elements and is switched to a pattern of series, parallel, series-parallel combination, or parallel-parallel combination by switching a connection between the coil elements. A switch for this switching is arranged between the coil elements, and both ends of a coil element among the coil elements, except the coil elements at both ends, are connected to two switches, respectively, resulting in that there is a total of four switches that directly connect to the coil element.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine, and more particularly to a rotating electric machine suitable for efficient operation, and an electric vehicle using the same. [Background technology]

[0002] As a technique for changing the characteristics of a motor as a rotating electric machine, switching the connection of internal windings has been proposed, as disclosed in Patent Document 1 and Patent Document 2. For example, Patent Document 1 is a technique related to a motor for machine tools, in which a coil consisting of three phases is used as a stator, and the coils that make up each phase are made up of multiple coil elements with different numbers of turns. Then, one to multiple coil elements are selectively connected in series so that the total number of turns of the coil is reduced during high-speed rotation and the total number of turns of the coil is increased during low-speed rotation.

[0003] Furthermore, Patent Document 2 discloses technology related to motors primarily for starter generators for power tools or automobiles. Like the motor disclosed in Patent Document 1, the motor disclosed in Patent Document 2 also uses a stator made up of coils consisting of three phases. Each phase is made up of multiple coil elements, and the motor is configured with a switch device that can switch between connecting the multiple coil elements making up each phase in series or parallel. With this configuration, in series connection, the magnetic field excited by the coils is stronger, improving torque, while in parallel connection, the magnetic field is weaker, enabling high-speed rotation.

[0004] Patent Documents 3 and 4 also state that in a coreless motor having multiple phases, the characteristics of the motor can be varied by determining whether the connection method for each phase is series or parallel. Furthermore, Patent Document 5 states that in a motor having fixed coils, a circuit is used to switch the connection method for the coil elements that make up the three-phase coil between series and parallel. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3596711 [Patent Document 2] Special Publication No. 2010-537621 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-121102 [Patent Document 4] Japanese Patent Application Publication No. 2019-54628 [Patent Document 5] Japanese Patent Application Laid-Open No. 2011-229221 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the techniques disclosed in Patent Documents 1 and 2, it is certainly possible to change the characteristics of a motor and realize the functions of multiple motors with a single motor.

[0007] However, with the technology disclosed in Patent Document 1, the number of coil turns essentially changes, which may result in a significant drop in torque at high rotation speeds. Also, with the technology disclosed in Patent Document 2, there is a concern that the self-inductance is large due to the influence of the iron core, which may result in a time lag between switching and the change in characteristics.

[0008] Furthermore, the coreless motors disclosed in Patent Documents 3 and 4 have small capacities. Therefore, the concept of switching motor characteristics during use was not possible. Furthermore, it was common knowledge among those skilled in the art that increasing the capacity of a coreless motor could result in deformation due to the counter torque generated when the stator coil rotates the rotor, making it unsuitable for large capacity applications. Therefore, it was common technical knowledge that the cored motor technology disclosed in Patent Document 5 could not be applied as is.

[0009] Therefore, the present invention aims to solve the above problems and break through conventional technical common sense by providing a rotating electric machine that can be applied to large-capacity coreless motors, can maintain a predetermined torque even at high rotation speeds, and can improve responsiveness when switching characteristics, and an electric vehicle using the same. [Means for solving the problem]

[0010] To achieve the above object, the present invention provides a rotating electric machine comprising a housing, a permanent magnet, a stator, and three-phase stator coils, each of which has three or more coil elements. The connections between the coil elements can be switched to series, parallel, a series-parallel combination, or a parallel-parallel combination. Switches for this switching are disposed between the coil elements, and each of the coil elements except for the coil elements at both ends is connected to two switches, resulting in a total of four switches directly connected to the coil elements. In terms of the total number of switches and coil elements, if the number of coil elements per phase (ignoring auxiliary coils, as described below) is X, then the total number of switches is roughly (5X - 6). Note that in this application, the coil elements are of the same shape and quality.

[0011] In addition, in a rotating electric machine having the above-mentioned features, it is desirable that the stator coil is cylindrical, and that the rotor has the permanent magnet positioned on the surface opposite the stator coil and spaced apart from the stator coil. Also, the number of coil elements for each phase may be either even or odd.

[0012] Furthermore, in a rotating electric machine having the above-described characteristics, it is desirable to halve the resistance of one of the multiple coil elements by connecting another coil element in parallel with that coil element or by doubling the cross-sectional area of ​​that coil. In this application, this "coil element added in parallel" is sometimes referred to as an "auxiliary coil." Having such characteristics reduces the resistance of that coil element, thereby contributing to a reduction in the resistance of the entire coil.

[0013] Furthermore, in a rotating electric machine having the above characteristics, it is desirable to not use the pattern in which all of the coil elements are connected in parallel, among the coil element connection switching patterns assumed based on the number of coil elements used. When all of the coil elements are connected in parallel, the maximum rotation speed of the motor is significantly higher than that of a motor corresponding to the coil element connection pattern with the second highest maximum rotation speed, which increases the switching shock to the driver and the equipment. However, by not using the pattern in which all of the coil elements are connected in parallel in this way, the shock can be reduced accordingly.

[0014] Furthermore, in a rotating electric machine having the above-described characteristics, the TN characteristics of the motor are determined for each coil element connection switching pattern assumed from the number of coil elements used, and multiple motors with different TN characteristics are assumed based on this, and the motors are selected so that the range between the maximum rotation speeds of any two of the motors (including the range from zero rotation speed in the case of the maximum rotation speed when all are connected in series) is substantially equal (within a range of (1±0.5) times the maximum rotation speed when all coil elements are connected in series, and excluding cases where this range is too small, such as less than 0.5), and motor patterns that do not satisfy this condition are desirably not used. With such a configuration, fine switching can be omitted, making switching control easier, and the switching intervals according to the maximum rotation speed are approximately uniform, making it easier for the driver to operate intuitively.

[0015] In addition, in a rotating electric machine having the above-described characteristics, it is also effective to enable the parallel connection of the coil elements to be switched in multiple stages by changing the number of coil elements in a pair according to the number of coil elements constituting each phase. By having such a characteristic, it becomes possible to change the number of coils connected in parallel in accordance with the desired characteristics of the rotating electric machine.

[0016] Furthermore, in a rotating electric machine having the above-described characteristics, the switch can be configured using one or more semiconductor elements. This configuration makes it possible to reduce the size and weight of the rotating electric machine itself, and also simplifies the internal wiring.

[0017] Furthermore, a rotating electric machine having the above-described characteristics may be provided with a control unit that switches the circuit unit so that the number of coil elements connected in series increases on the low rotation speed side relative to a predetermined threshold rotation speed, and the number of coil elements connected in parallel increases on the high rotation speed side. By having such characteristics, it is possible to achieve a balance between power consumption and generated torque, and to widen the usable rotation range.

[0018] In addition, in a rotating electric machine having the above-described characteristics, the stator coil may be configured to have a deformation-resistant layer. This configuration allows for the provision of a gap in the motor's internal space, thereby enabling the motor's internal space to be utilized more effectively. Furthermore, by providing deformation resistance, deformation of the stator coil due to the counter torque generated when the rotor rotates can be prevented, even when the motor capacity is increased.

[0019] In addition, in a rotating electric machine having the above-described characteristics, the stator coil preferably has three phases: U, V, and W. By having such characteristics, it is possible to avoid an increase in the number of coils and circuits, and to reduce manufacturing costs during mass production.

[0020] In a rotating electric machine having the above-mentioned characteristics, the coil elements may be preferably made of Litz wire, which provides the strength necessary to maintain the shape of the stator coil and eliminates the need to use iron or copper plates for the stator coil, thereby reducing self-inductance.

[0021] Furthermore, an electric vehicle for achieving the above object is characterized in that a rotating electric machine having the above characteristics is used as a propulsion power source. [Effects of the Invention]

[0022] A rotating electric machine with the above-mentioned characteristics can accommodate larger capacities than conventional common sense, and can maintain a predetermined torque even at high rotation speeds while improving responsiveness when switching characteristics. Each intermediate coil element located between the power supply line (V) and the COM line has two switches on both ends so that the current flowing through it is first connected to V and / or an adjacent coil element, and then connected to an adjacent coil element and / or the COM line at the other end. This makes it possible to prevent excessive heat generation (overload) in the switch depending on its position, and enables the device to be expanded to connect a large number of coil elements.

[0023] Furthermore, since the motor function changes each time the coil element connection is switched (hereinafter referred to as coil switching), a different motor exists for each coil switching pattern. Each motor has its own maximum rotation speed. Therefore, one motor device (motor as hardware configuration) will have multiple motors that share coil elements and switches. Furthermore, coil switching refers to switching the electrical connection between coil elements. For example, the cylindrical coil of a coreless motor refers to a combination of multiple coil elements formed into a cylindrical shape. In other words, the word "coil" includes both "coil elements" and the "coil body" as the completed combined product. [Brief explanation of the drawings]

[0024] [Figure 1]FIG. 2 is a diagram showing the circuit configuration of a stator coil in the motor according to the first embodiment, illustrating an example in which all four coil elements constituting each phase are directly connected. [Figure 2] FIG. 1 is a diagram showing the circuit configuration of a stator coil in a motor according to a first embodiment, illustrating an example in which two of the four coil elements constituting each phase are connected in series, and the coils that make up a set of series connections are connected in parallel. [Figure 3] FIG. 2 is a diagram showing the circuit configuration of a stator coil in the motor according to the first embodiment, illustrating an example in which all four coil elements constituting each phase are connected in parallel. [Figure 4] FIG. 4 is a diagram showing the circuit configuration of a stator coil in a motor according to a first embodiment, and is an explanatory diagram summarizing FIGS. 1 to 3. [Figure 5] 1 is a side cross-sectional view showing a schematic configuration of a coreless motor as a motor device according to an embodiment of the present invention. [Figure 6] 4 is a graph showing changes in characteristics when the motor according to the first embodiment is operated by switching the connection method of the coil elements that make up the stator coil. [Figure 7] FIG. 10 is a diagram showing a specific example of operation switching when a three-stage switching motor is applied to a vehicle (relationship between change in rotation speed and connection switching). [Figure 8] FIG. 10 is a diagram showing a specific example of operation switching when a three-stage switching motor is applied to a vehicle (relationship between speed change and connection switching). [Figure 9] FIG. 10 is a diagram showing a specific example of operation switching when a three-stage switching motor is applied to a vehicle (relationship between changes in road surface inclination conditions and connection switching). [Figure 10] FIG. 1 is a diagram illustrating a system for operating a motor including a coil switching device that can be applied to each embodiment. [Figure 11] FIG. 10 is a diagram showing an application of the second embodiment in which one phase has 12 coil elements and five circuit units. [Figure 12] FIG. 11 is a cross-sectional view showing an example of a coil arrangement when 12 coil elements are used according to the second embodiment. [Figure 13] FIG. 10 is a diagram showing an example of a circuit in a motor with 12 coil elements and six-stage switching according to a second embodiment, and a partially enlarged view of the portion surrounded by dashed line A in the figure is shown in the same figure. [Figure 14] 13 is a table showing the switching of the circuit units in FIG. 12 and the change in the connection state. [Figure 15] FIG. 10 is a diagram illustrating an example of a circuit in which a stator coil is configured with two phases according to a third embodiment. [Figure 16] FIG. 11 is a schematic diagram illustrating an example in which coil elements of each phase are connected in series in a two-phase stator coil according to a third embodiment. [Figure 17] FIG. 11 is a schematic diagram illustrating an example in which coil elements of each phase are connected in parallel in a two-phase stator coil according to a third embodiment. [Figure 18] FIG. 10 is a diagram illustrating an example of a circuit in which a stator coil is configured with five phases according to a fourth embodiment. [Figure 19] FIG. 11 is a schematic diagram illustrating an example in which coil elements of each phase are connected in series in a five-phase stator coil according to a fifth embodiment. [Figure 20] FIG. 11 is a schematic diagram illustrating an example in which coil elements of each phase are connected in parallel in a five-phase stator coil according to a fifth embodiment. [Figure 21] FIG. 10 is a coil connection circuit diagram in the sixth embodiment, in which the number of coil elements constituting a phase of the stator coil is an odd number (five coil elements). [Figure 22] FIG. 13 is a coil connection circuit diagram of an application example in which the number of coil elements constituting a phase that constitutes a stator coil is an odd number (five coil elements) according to the seventh embodiment. [Figure 23] FIG. 13 is a diagram illustrating an example of coil switching and operation switching using five coil elements according to the seventh embodiment. [Figure 24] FIG. 10 is a diagram showing the relationship between a clock and Lo and Hi levels of various command signals when the circuit section is configured using switching elements. [Figure 25]FIG. 10 is a diagram illustrating a configuration example of a control unit that outputs a command signal to a circuit unit using a switching element. [Figure 26] FIG. 2 is a diagram illustrating an example of a circuit of a block that constitutes each phase. [Figure 27] FIG. 13 is a diagram illustrating an example of a circuit configuration in which the number of coil elements constituting a phase of a stator coil is three, and the coil elements are connected in series, according to the eighth embodiment. [Figure 28] FIG. 13 is a diagram illustrating an example of a circuit configuration in which the number of coil elements constituting a phase of a stator coil is three, and the coil elements are connected in parallel, according to the eighth embodiment. [Figure 29] FIG. 20 is an explanatory diagram illustrating an example of a coil connection switching pattern in three coil elements according to the eighth embodiment. [Figure 30] FIG. 10 is a diagram illustrating variations in connection switching patterns, including cases where some coil elements are not used, when the number of coil elements forming the phases that make up the status coil is four. DETAILED DESCRIPTION OF THE INVENTION

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a rotating electric machine and an electric vehicle according to the present invention will be described in detail with reference to the drawings. Note that the following embodiments will be described by taking a motor device as an example of the rotating electric machine.

[0026] [Basic configuration] First, the basic configuration of a motor device 10 according to this embodiment will be described with reference to Figure 5. The motor device 10 according to this embodiment is a so-called coreless motor that is basically composed of a housing 12, a rotating shaft 14, a stator coil 18, and a rotor 16. The housing 12 is an element that forms the outer shell, and houses the rotating shaft 14, the stator coil 18, and the rotor 16 in its internal space. The rotating shaft 14 is disposed so as to pass through the housing 12, and is rotatably supported by a bearing 12a provided at the intersection with the housing 12.

[0027] Stator coil 18 is configured to have a cylindrical shape and is made up of coil groups divided into multiple phases (three phases: U, V, and W in this embodiment). The U, V, and W phases that make up stator coil 18 are each made up of multiple coil elements that make up poles. Stator coil 18 configured in this way is configured so that one end face is supported by a stator (housing 12 in the example shown in FIG. 5) which is a fixed member.

[0028] The rotor 16 has a cylindrical outer yoke 16c, an inner yoke 16b, and a permanent magnet 16a, and one end face is connected to the rotating shaft 14. The outer yoke 16c is an element located on the outer peripheral side of the stator coil 18 (on the outer peripheral side in the radial direction from the center of the cylinder), and the inner yoke 16b is an element located on the inner peripheral side of the stator coil 18. In the motor device 10 according to this embodiment, the permanent magnet 16a is configured to be provided inside the outer yoke 16c, on the surface facing the stator coil 18.

[0029] A coreless motor with this configuration can obtain a large output and torque compared to the size of the motor device because the power source is separated from the rotating shaft 14. Also, because the stator coil 18 does not have an iron core, self-inductance can be kept small.

[0030] Furthermore, in each embodiment of this specification, when constructing the stator coil 18, Litz wire is used for the winding and is shaped by coating with an insulating layer. The Litz wire is made up of a bundle of multiple conductive fine wires, and the outer periphery of each conductive fine wire is covered with an insulating layer such as enamel. Furthermore, the outer periphery of the conductive fine wires (the bundle of conductive wires) is provided with an outer skin layer made of a fibrous material such as glass fiber.

[0031] This configuration can suppress the generation of eddy currents (eddy current loss) that occurs when iron or copper plates are used to maintain the shape, and can contribute to reducing self-inductance.

[0032] [First embodiment] First, the configuration of a motor device 10 according to a first embodiment will be described with reference to Figures 1 to 4. The motor device 10 according to this embodiment also has the configuration shown in Figure 5.

[0033] The stator coil 18 according to this embodiment is a three-phase, twelve-pole coil with four coil elements per phase (12 in total). In the stator coil 18 configured as described above, switch circuits 20 (20U1, 20U2, 20U3, 20V1, 20V2, 20V3, 20W1, 20W2, 20W3; hereinafter referred to as circuit units 20) are provided between the coil elements constituting each phase (first coil element U1, second coil element U2, third coil element U3, fourth coil element U4, first coil element V1, second coil element V2, third coil element V3, fourth coil element V4, first coil element W1, second coil element W2, third coil element W3, fourth coil element W4).

[0034] Regarding the configuration of circuit units 20, circuit units 20U1, 20U3, 20V1, 20V3, 20W1, and 20W3, each circuit unit 20 is configured with two changeover switches (first switch A and second switch B) arranged in parallel, each with one input port and two output ports. Taking the leftmost coil as an example, the first coil elements U1, V1, and W1 are connected to the input port of first switch A, and a first bypass line is connected to the input port of second switch B. The output port of first switch A is connected to second coil elements U2, V2, and W2 on the a side, and a second bypass line is connected to the b side. Furthermore, the output port of second switch B is open (unconnected) on the a side, and branch lines from second coil elements U2, V2, and W2 are connected to the b side. On the other hand, in circuit sections 20U2, 20V2, and 20W2, the second switch B is configured so that the number of input ports and the number of output ports are reversed to those of the first switch A. Thus, the two coils in the middle section, excluding the end coils, each have two switches on both the left and right sides. The left switch of each selects whether to connect to the coil one step below or to the midpoint line, and the right switch selects whether to connect from the power line or from the coil one step before.

[0035] In a motor device 10 configured as described above, by setting the first switch A and the second switch B to port a for each of the circuit sections 20U1 to 20W3 in the U, V, and W phases, the first coil element U1 to the fourth coil element U4, the first coil element V1 to the fourth coil element V4, and the first coil element W1 to the fourth coil element W4 are each connected in series (this state is called 1 parallel: see Figure 1).

[0036] Furthermore, when the first switch A and the second switch B of the circuit units 20U2, 20V2, and 20W2 are set to the b port from the 1-parallel state, for example, in the U phase, the first coil element U1 and the second coil element U2 are connected in series, and the third coil element U3 and the fourth coil element U4 are connected in series, and the pair of the first coil element U1 and the second coil element U2 and the pair of the third coil element U3 and the fourth coil element U4 are connected in parallel. Note that the coil elements are connected in the same way in the V phase and the W phase (this state is called 2-parallel: see FIG. 2).

[0037] Furthermore, in each of the U-phase, V-phase, and W-phase, when the first switch A and the second switch B are set to the b port for each of the circuit sections 20U1 to 20W3, the first coil element U1 to the fourth coil element U4, the first coil element V1 to the fourth coil element V4, and the first coil element W1 to the fourth coil element W4 are connected in parallel (this state is called 4-parallel: see FIG. 3). Note that the switches may be switched in response to a signal from the control section 22.

[0038] The circuits in Figures 1 to 3 can be consolidated to produce the circuit information in Figure 4. As this diagram shows, the two middle coil elements (excluding the two ends of the four coil elements of each phase) are each connected to two switches at both ends (for the U2 coil element, the left end is connected to switches USw2 and USw3, and the right end is connected to switches USw4 and USw5), for a total of four (the same is true for the U3 coil element, with the left connected to USw5 and USw6 and the right connected to USw7 and USw8, and the same is true for the other phases (V, W)). With this type of connection, the current flowing through each switch is the same, preventing excessive heat generation.

[0039] In the motor device 10 configured as described above, the more coil elements connected in series in the system, the higher the torque characteristics (the above-mentioned 1-parallel), and the more coils connected in parallel in the system, the higher the rotation characteristics (the above-mentioned 4-parallel). Taking advantage of these characteristics, the relationship between torque and rotation speed (TN characteristics) and the relationship between torque and current (TI characteristics) when operating the motor device 10 by switching between 1-parallel and 4-parallel systems are shown in Figure 6.

[0040] As shown in Figure 6, by switching the system from 1-parallel to 2-parallel to 4-parallel as the rotation speed increases, it is possible to achieve high-torque operation while keeping power consumption below a predetermined value. Furthermore, by switching between 2-parallel and 4-parallel operation, it is possible to achieve operation in a high rotation range that cannot be achieved with 1-parallel. For example, if a motor device 10 with this configuration is used to power the propulsion of an electric vehicle, the 4-parallel, 2-parallel, and 1-parallel (i.e., all coil elements in series) will function as a transmission mechanism equivalent to top gear, second gear, and low gear, respectively.

[0041] [effect] A motor device 10 configured in this way can obtain a predetermined torque even in the high rotation range. Furthermore, if a coreless motor is used, the coil body does not have an iron core, so iron loss is eliminated, self-inductance can be kept small, and responsiveness from switching by connection changeover in the circuit section 20 to characteristic changeover can be improved. Furthermore, by increasing the number of coil elements and circuit sections, the degree of freedom in characteristic changeover can be improved.

[0042] [Operation Switch] A specific example of operation switching when the motor device 10 according to this embodiment is applied to an electric vehicle will be described with reference to Figures 7 to 10. This embodiment corresponds to an example of operation switching in all electric vehicles, such as wheelchairs, motorcycles, electric bicycles, so-called senior cars, automobiles, and AGVs (automated guided vehicles), and can also be seen as common to changes in rotation speed and load in electric lawnmowers equipped with rotary blades, etc.

[0043] As can be seen from Figure 7, at the start (= when the vehicle starts moving), the rotation speed is low and initial torque is required to move the vehicle, so the connection type of the coil elements is set to L (low), i.e., in series (1 parallel; if there are four coil elements, all four coil elements are in series, i.e., 4S). After starting, for example, when the rotation speed of the motor device 10 reaches 700 rpm (equivalent to 30 km / h), the connection automatically switches from L to 2 parallel (2P+2P if there are four coil elements in total). Note that in this example, the connection is set to automatically switch depending on the rotation speed of the motor device 10. Therefore, if the vehicle speed is further increased, for example, and the rotation speed of the motor device 10 reaches 1400 rpm (equivalent to 60 km / h), the connection will switch to 4 parallel (all four coil elements in parallel).

[0044] If the vehicle speed is further increased and the vehicle continues traveling at 100 km / h (for example, the rotation speed of the motor unit 10 is 2000 rpm) in 4-parallel mode, when the vehicle enters a slight uphill slope (inclination angle α), the load on the motor unit 10 increases, causing the rotation speed to decrease and the speed to drop. For example, when the rotation speed drops to about 1167 rpm (equivalent to 50 km / h: 5 / 6 of 1400 rpm), the transmission switches to 2-parallel mode.

[0045] Furthermore, when the vehicle goes from a slight uphill slope to a steep slope (inclination angle β), the load on the motor device 10 increases further, the rotation speed drops, and the speed decreases. For example, when the rotation speed drops to about 467 rpm (equivalent to 20 km / h: 2 / 3 of 700 rpm), the system automatically switches to in-line (1 parallel, i.e., 4S:L). Note that when traveling up a slope, settings such as 50 km / h (1167 rpm) and 20 km / h (467 rpm) correspond to the hysteresis fluctuation width.

[0046] When the vehicle gradually accelerates while traveling uphill and reaches a speed of approximately 30 km / h (700 rpm) on a flat road, the connection type of the motor device 10 automatically switches to 2-parallel (2P+2P). Furthermore, when the vehicle accelerates further on a flat road and reaches a speed of 60 km / h (1400 rpm), the connection type changes to 4-parallel (4P), allowing the vehicle to accelerate up to approximately 100 km / h (2000 rpm). Up to this point, as the rotational speed of the motor device 10 increases, the coil connection pattern switching device 80 (see FIG. 10; the same applies below) automatically switches the gear function.

[0047] On the other hand, when the vehicle enters a downhill slope (for example, a steep slope with an inclination angle γ), the coil connection pattern switching device 80 switches the connection pattern in response to a command signal from the rider, and the motor device 10 is controlled to apply braking (= regenerative braking: so-called engine braking) using the rotational resistance of the motor device 10. In this way, automatic control and manual control may be combined. For example, on a steep slope, the speed is gradually reduced in 4-parallel (4P) mode to approximately 60 km / h (1400 rpm). Then, when the downhill slope becomes gentler (for example, with an inclination angle θ), the speed is switched to 2-parallel (2P+2P) and further reduced. By gradually reducing the speed (rotation speed) in this way, it is possible to prevent a sudden load from being applied to the motor device 10.

[0048] When the vehicle speed drops to about 30 km / h (700 rpm) on a gentle downhill slope, the connection type of the motor device 10 is switched to 1 parallel (series, i.e., 4S) and the vehicle reaches a flat road. Note that when going downhill, the power supply can be charged by using regenerative braking as described above.

[0049] The above flow is shown in FIGS. 8 and 9 as switching between high speed (Top: T), medium speed (Second: S), and low speed (Low: L), and will be explained below.

[0050] First, the vehicle starts on flat ground and travels in L mode at speeds between 0 and 20 km / h. At 20 km / h, it switches to S mode, and at 60 km / h, it switches to T mode, and at T, it reaches 100 km / h. In section A shown in Figure 8, the accelerator is fully open, and the coil connection pattern switching device 80 detects the rotation speed of the motor device 10 and automatically switches the coil element connection. In this section, the rotation speed of the motor device 10 increases as the vehicle accelerates, but the accelerator signal (manual accelerator signal) input by the driver is output as a signal to increase the rotation speed to the maximum. As a result, the manual accelerator signal becomes greater than the rotation speed of the motor device 10.

[0051] Next, when the vehicle enters an uphill slope, the speed drops to about 60 km / h, and the coil connection pattern switching device 80 switches to S, and maintains the S state even when the vehicle subsequently enters an even steeper slope. In this section (section B' in FIG. 8), the coil connection pattern switching device 80 is not controlled by the rotation speed (speed) of the motor device, but is controlled by the accelerator opening (current control). Then, when the vehicle reaches the top of the slope and enters flat ground (exiting section B'), the control switches to rotation speed control (speed control), and the coil connection pattern switching device 80 switches to L to accelerate the vehicle, then switches to S as the speed (rotation speed) increases, and then switches to T. Here, the top speed at T reaches about 100 km / h.

[0052] In section B shown in FIG. 8, priority is given to switching control of the coil connection pattern switching device 80 based on the accelerator opening. Therefore, when the rotation speed (speed) of the motor device 10 is lower than the instruction based on the accelerator opening, the coil connection pattern switching device 80 performs switching based on the current instruction based on the accelerator opening. In other words, in section B', the rotation speed of the motor device 10 drops as the vehicle speed decreases, but the coil connection pattern switching device 80 automatically operates and switches based on the current value to maintain the vehicle speed at 60 km / h. As described above, in section B, the rotation speed (speed) of the motor device 10 relative to the accelerator opening remains low. Therefore, in section B as well, the manual accelerator signal becomes greater than the rotation speed of the motor device 10.

[0053] Next, when the vehicle enters a downhill slope from a flat road, it starts down in T mode even if the downhill slope is steep, switches to S after the slope becomes gentler, and then switches to L when the vehicle reaches flat ground. In this section C, the rotation speed (speed) of the motor device 10 becomes greater than the accelerator opening (current command) due to gravity acceleration. Therefore, switching is performed by the coil connection pattern switching device 80 in accordance with the driver's adjustment of the accelerator opening (accelerator command). The above-mentioned switching of the accelerator opening is performed by the coil pattern switching of the present invention.

[0054] Next, another embodiment of the driving mode switching pattern is shown in FIG. 9. In the example shown in FIG. 9, top gear is selected in the range from flat ground to a small uphill slope. Thereafter, when the slope of the uphill slope becomes medium, the gear is switched to second gear, and when the slope becomes steeper, the gear is switched to low gear. Then, when the slope reaches a gentler angle, the gear is switched to second gear again, and when the vehicle reaches a plateau and flat ground, the gear is switched to top gear. In this manner, the coil connection pattern switching device 80 has the gear switching function of a conventional automobile. In other words, this gear switching is performed by switching the coil element connection pattern.

[0055] Generally, there is a trade-off between increasing the torque of a motor and increasing its maximum rotation speed. Increasing the torque of a motor results in a lower maximum rotation speed, while increasing the maximum rotation speed results in a lower maximum torque. Conventionally, increasing the voltage of the power supply and increasing the torque have been achieved by increasing the power supply's current, but these control methods have safety issues and technical limitations. The inventors therefore considered automatically electrically switching between motors with different characteristics, thereby resolving this conventional problem. By adopting such a method, a single motor device can be used, while enabling multi-stage circuit switching (switching of coil connections using a coil connection pattern switching device 80)—for example, between a low gear, a second gear, and a top gear—to achieve the same effect as automatically switching between multiple motors with different characteristics.

[0056] Here, low gear has high torque and low rotation speed, and high torque can be generated with little current. To increase rotation speed in low gear, high voltage is required, but since low gear operates at low rotation speed, high voltage is not required. Also, 2nd gear has medium torque and medium rotation speed, and top gear has low torque and high rotation speed (high speed rotation is possible with low voltage). To obtain high torque in top gear, a large current is required, but since top gear operates at low torque, high current is not required.

[0057] In this way, by providing the motor with the ability to switch the connections between coil elements, one motor device 10 can have multiple motor faces built in, making it possible to handle a variety of driving situations. This eliminates the need for high voltage and large current outputs from the driver, reduces overload on the motor device, and prevents sudden increases in temperature in the motor device.

[0058] As described above, the motor device 10 according to the present invention enables three or more stages of characteristic switching by selecting the position and number of coil elements for each phase to switch between a series Low state, multiple parallel states (e.g., second and third states), or a combination of series and parallel states. That is, by selecting the position and number of coil element connections for each phase, the connection type can be switched between a series state and multiple parallel states. Therefore, when applied to electric vehicles such as bicycles, motorcycles, so-called senior cars, wheelchairs, and automobiles, a function equivalent to multiple gear switching (switching of coil element connections) can be achieved without the need for mechanical gears. This configuration can be applied not only to the coreless motor according to the present invention, but also to cored motors.

[0059] When the motor device 10 according to the present invention is applied to a propulsion power source for an electric vehicle, the vehicle speed (vehicle speed) of the electric vehicle to which the motor device 10 is applied is detected by an encoder or resolver, and the coil switching is performed based on the detected vehicle speed value. Vehicle speed detection may be performed using a sensor (not shown), or various conventional (known) methods may be used. The timing for switching the coil element connections is determined by the coil connection pattern switching device 80, which has switching timing settings set based on various speed detection methods.

[0060] The total number of coil elements for each phase is divided according to the number of switching stages (series (=1 parallel), multiple parallel patterns). It is desirable to divide the coils equally to prevent circulating currents from occurring between the coils. For example, if the total number of coil elements is 24, then for series (1 parallel), the number should be 24 coil elements, and for 2 parallel, the number should be 12 coil elements. Similarly, for 3 parallel, the number should be 8 coil elements, for 4 parallel, the number should be 6 coil elements, and for 6 parallel, the number should be 4 coil elements. Further increasing the number of divisions, the number should be 3 coil elements for 8 parallel, 2 coil elements for 12 parallel, and 1 coil element for 24 parallel. Dividing the coil elements evenly in this way eliminates differences in the number of parallel coil elements in each phase, preventing circulating currents from occurring. This suppresses heat generation due to circulating currents and avoids increased energy (power) loss.

[0061] The system diagram in Figure 10 shows the connection relationship between the controller 31, driver 40, coil connection pattern switching device 80, and motor device 10. First, the controller 31 determines the torque to be output from the motor device 10 based on throttle information and speed information. The throttle information is the throttle opening, which is 0% when the throttle is closed and 100% when at full throttle. The controller 31 selects the gear value automatically or manually. The motor current is calculated from the selected gear value and torque value. Torque constant information for each gear is provided for the motor current calculation.

[0062] The driver 40 controls the motor so that the motor current value matches the command value from the controller 31, and also provides the motor rotation speed N as speed information to the controller 31. Regarding gear selection, a low gear is selected when the rotation speed is low, and a higher gear is selected when the rotation speed is high. Torque is determined according to a torque map pre-stored in the controller 31. This torque map is composed of torque values ​​corresponding to, for example, multiple throttle states and multiple speeds. The actual torque to be output is calculated by interpolation from the actual throttle state and speed and this torque map. For example, the torque to be output corresponding to six types of throttle information and speeds—when the throttle is closed (0%), when it is 20%, when it is 40%, when it is 60%, when it is 80%, and when it is full throttle (100%)—is stored in the controller 31 as a torque map. The controller 31 then calculates the torque value from the speed N, the throttle information, and this torque map. If the throttle value is other than the six values ​​mentioned above (0%, 20%, 40%, 60%, 80%, 100%), the torque value is calculated by interpolation.

[0063] As described above, gear switching is performed by switching the coil connection pattern using the coil connection pattern switching device 80. In this way, gears are switched in accordance with the rotation speed.

[0064] The controller 31 calculates the current value required for each gear to generate the specified torque to be output and instructs the driver 40. The current command to the driver 40 is executed simultaneously with the gear change command. Therefore, output torque fluctuations during gear change are very small, achieving smooth gear change. In other words, a current command that maintains torque constant before and after change is issued simultaneously with the change, resulting in smooth gear change. For example, assuming a system with a torque constant of 0.4 Nm / A in first gear and 0.2 Nm / A in second gear, if the torque to be output in first gear is 1 Nm, the controller 31 instructs the driver 40 to issue a current command of 2.5 A. When the rotational speed increases and it is time to change to second gear, the controller 31 changes the current command to the driver 40 from 2.5 A to 5 A simultaneously with the change command. As a result, the torque output from the motor device 10 is maintained at 1 Nm before and after change, achieving smooth gear change.

[0065] The circuits described in the above embodiments can be built into the motor device 10. When the circuits are housed within the motor device, the internal space unique to coreless motors can be effectively utilized. Furthermore, when the motor device 10 is a coreless motor, it can maintain its function as a rotating electric machine without necessarily providing a rotating shaft 14. This is possible because the rotating shaft 14 and rotor 16 are not connected by a core. For example, this can be achieved by connecting the rotating shaft of an input / output device directly to the rotor. With this configuration, the motor device 10 has a hollow structure, allowing for more effective utilization of the internal space.

[0066] Furthermore, in the above embodiment, it has been described that the coil connection pattern switching device 80 performs switching based on the rotation speed of the motor device 10. However, when the motor device 10 according to the present invention is applied to a propulsion power source for an electric vehicle, it is also possible to detect the vehicle speed (vehicle speed) of the electric vehicle to which the motor device 10 is applied, and perform switching by the coil switching pattern switching device 80 based on the detected vehicle speed value. Note that the vehicle speed may be detected using a sensor or the like (not shown), and various conventional (known) methods may be used.

[0067] [Application form] In all of the above embodiments, a circuit unit is provided for each single coil unit. However, the number of coil elements arranged between circuit units is not limited to one. For example, by varying the number of coil elements arranged between circuit units and devising the arrangement of the circuit units, it becomes possible to equalize the number of coil elements connected in series when connecting coil elements in parallel, thereby widening the range of characteristic changes that can be achieved by combining coil elements connected in series and coil elements connected in parallel.

[0068] For example, in a motor device 10 having a stator coil 18 configured as shown in FIG. 11, 12 coil elements (first to twelfth coil elements: U1-W12) are arranged in each phase (U-phase, V-phase, W-phase), and five circuit units (20U1-20W5) are provided. As an example, in the U-phase, the circuit units (20U1-20U5) are respectively provided between coil elements U3 and U4, between coil elements U4 and U5, between coil elements U6 and U7, between coil elements U8 and U9, and between coil elements U9 and U10. The circuit units (20V1-20W5) are similarly arranged in the V-phase and W-phase.

[0069] The circuit units (20U1-20W5) are each provided with ports a1, b1, a2, b2, c1, and c2. In the circuit units (20U1-20W5) having such ports, ports a1 and b1 are switchable with port c1, and ports a2 and b2 are switchable with port c2, and both are configured to switch simultaneously.

[0070] Next, the relationship between switching of the connection configuration of the stator coil 18 and switching of the circuit units (20U1-20W5) in this embodiment will be described. Note that since the corresponding circuit units (20U1-20W5) in each phase are switched simultaneously, in the following description, circuit units 20U1, 20V1, and 20W1 will be referred to as circuit unit 20X1, circuit units 20U2, 20V2, and 20W2 as circuit unit 20X2, circuit units 20U3, 20V3, and 20W3 as circuit unit 20X3, circuit units 20U4, 20V4, and 20W4 as circuit unit 20X4, and circuit units 20U5, 20V5, and 20W5 as circuit unit 20X5.

[0071] In the motor device of this embodiment, in the case of a 1-parallel (series connection), switching is set so that port a and port c are connected in all circuit units 20X1-20X5. In addition, in the case of a 2-parallel configuration, switching is set so that port b and port c are connected only in circuit unit 20X3. In addition, in the case of a 3-parallel configuration, switching is set so that port b and port c are connected in circuit units 20X2 and 20X4. Furthermore, in the case of a 4-parallel configuration, switching is set so that port b and port c are connected in circuit units 20X1, 20X3, and 20X5.

[0072] When the coil elements constituting each phase are arranged cylindrically, the result is a configuration as shown in Figure 12. In the example shown in Figure 12, the boundary between coil element U1 and coil element U12 is used as the power input / output terminal, and coil elements U1-U12 are arranged clockwise to form a cylindrical (annular) shape. When the above-mentioned two parallel connections are implemented in a coil arranged in this manner, the coil is divided (divided into two equal parts) by circuit unit 20U3, and coil elements U1-U6 and coil elements U7-U12 are connected in series, respectively. When the above-mentioned three parallel connections are implemented, the coil is divided (divided into three equal parts) by circuit units 20U2 and 20U4, and coil elements U1-U4, coil elements U5-U8, and coil elements U9-U12 are connected in series, respectively. Furthermore, when the above four parallel circuits are implemented, the coil is divided (into four equal parts) in circuit sections 20U1, 20U3, and 20U5, and coil elements U1-U3, U4-U6, U7-U9, and U10-U12 are connected in series, respectively. Note that while Figure 12 shows the coil element arrangement for the U phase, the same applies to the V and W phases.

[0073] FIG. 13 shows an example of a six-stage switching circuit using the present invention. This example uses three phases, U, V, and W, with 12 coil elements for each phase. The coil elements are connected in six stages: 1 parallel (i.e., series), 2 parallel, 3 parallel, 4 parallel, 6 parallel, and 12 parallel (2 or more parallel). For simplicity's sake, the example shown in FIG. 13 uses a combination of relays as shown. However, the circuit device may be integrated using one or more switching elements (semiconductor elements) such as FETs. Using semiconductor elements to integrate the circuit device makes it possible to reduce the size and weight of the motor device 10 itself and simplify the internal wiring. In the figure, a1, a2, b1, b2, c1, and c2 indicate ports (contact points), Lu1 to Lu12, Lv1 to Lv12, and Lw1 to Lw12 indicate coil elements, and Ku1 to Ku11, Kv1 to Kv11, and Kw1 to Kw11 indicate circuit sections (relays).

[0074] Ports c1 and c2 in the circuit unit switch simultaneously; when port c1 is connected to port a1, port c2 is also connected to port a2. In this connection configuration, the coil elements on both sides of the circuit unit are connected in series. Port a2 in the circuit unit is an unused terminal (unconnected). On the other hand, when port c1 is connected to port b1, port c2 is also connected to port b2. In this connection configuration, the coil elements on both sides of the circuit unit are connected in parallel. If there are 11 such circuit units, one parallel (one parallel is in series), two parallel, three parallel, four parallel, six parallel, or twelve parallel can be selected, as shown in the table in Figure 14, depending on which circuit unit is selected as a or b. In the table, the x in Kx1 to Kx11 represents u, v, and w (for example, Kx1 of the U phase becomes Ku1).

[0075] To rotate the motor, multiple phases (three phases in the above explanation) are required, but the switching method shown in the table is the same for each phase. The switching operation can be automatic or manual, and the essence of this embodiment is that it is possible to switch multiple stages other than series. The switching operation is performed, for example, by selecting the number of stages using the system in Figure 10 and the gear switching operation means 30 in Figure 25 (explained later), sending a selection instruction to the controller 31, and the controller 31 sending an operation signal Sin to the shift register 32.

[0076] [Other than 3 phase: 2 phase and 5 phase examples] In the above embodiment, the stator coil 18 has been described as being configured with three phases: U, V, and W. However, the motor device 10 according to the present invention is not limited to three phases as long as the stator coil 18 is configured with multiple phases and allows for multiple-stage circuit switching between series and parallel.

[0077] Examples of two-phase stator coils 18 are shown in Figures 15 to 17. In the circuit diagram of Figure 15, when circuit section 20 is tilted toward the solid line, the coils constituting stator coil 18 are connected in series, and when it is tilted toward the dashed line, the coil elements are connected in parallel. Figures 16 and 17 are explanatory diagrams that schematically show the configuration of stator coil 18. In both figures, coils are drawn with two types of lines, solid and dashed, to indicate two phases. Also, the mountain-shaped portions close to permanent magnet 16a, indicated by S and N at the top of the figure, represent coils that form poles. Note that Figure 16 shows a state in which the coil elements are connected in series, and Figure 17 shows a state in which the coil elements are connected in parallel.

[0078] Next, an example of a five-phase stator coil 18 is shown in FIGS. 18 to 20. In the circuit diagram of FIG. 18, when the circuit section 20 is tilted toward the solid line, the coil elements are connected in series, and when it is tilted toward the dashed line, the coil elements are connected in parallel. FIGS. 19 and 20 are explanatory diagrams that schematically show the configuration of the stator coil 18. In both figures, the coils are represented by five different line types to indicate the five phases. Also, the mountain-shaped portions close to the permanent magnet 16a, indicated by S and N at the top of the figure, represent the coils that make up the poles. Note that FIG. 19 shows a state in which the coil elements are connected in series, and FIG. 20 shows a state in which the coil elements are connected in parallel.

[0079] [Example using 5 coil elements] Figure 21 is a switching pattern diagram illustrating the relationship between switch switching when five coil elements are used per phase. Assuming the reverse voltage per coil element length is 1V, 1Ω (the same applies hereinafter in this specification), (A) is the case when all five coil elements are connected in series (5S), resulting in a 5V back EMF of 5Ω. (B) is the case when all five coils are connected in parallel, resulting in 1V, 0.2Ω. (C) is the case of 3P+2P, resulting in 2V, 0.83Ω (=0.33Ω+0.5Ω), (D) is 2P+2P+1S, resulting in 3V, 2Ω (0.5Ω+0.5Ω+1Ω), and (E) is 2P+3S, resulting in 4V, 3.5Ω. In this way, 1V to 5V are available, but in consideration of the TN characteristics, the N interval narrows, so the 4V case (E) does not need to be used (in other words, in the coil switching function device (control mechanism including gear switching means), it is possible to set the desired usage pattern in advance within the selection range from among the possible connection patterns, and this makes the switching width almost uniform). As is clear from this diagram, each of the three intermediate coil elements sandwiched between the coil elements at both ends has only two switches connected to both ends, which saves on the number of switches overall and also suppresses excessive heat generation.

[0080] Figure 22 is an application example of Figure 21, in which an additional coil element is connected in parallel to one of the five coil elements. Although six coil elements are used, two of them essentially function as a single coil element. This additional coil element forms a twin section by adding one coil element in parallel to another (apparently branching), and so in this application, this additional coil is referred to as a complementary coil. Figure 22 (A) shows a case in which a complementary coil is attached to one of the five series coil elements. While the back-EMF voltage remains at 5V, the resistance is 4.5Ω, lower than Figure 21 (A). The following cases (B) to (E) also show lower resistance values ​​due to the addition of a complementary coil. In (B), all five coil elements are connected in parallel (5P), and a complementary coil is added to it, so there are effectively six coil elements in parallel. The back-EMF voltage is 1V, and the resistance is 0.167Ω (=1÷6). (C) is 3P + 2P + auxiliary coil, resulting in 2V, 0.66Ω (=0.33Ω + 0.33Ω), (D) is 2P + 2P + 1S + auxiliary coil, resulting in 3V, 1.5Ω (=0.5Ω + 0.5Ω + 0.5Ω), and (E) is 2P + 3S + auxiliary coil, resulting in 4V, 3Ω (=0.5Ω + 1Ω + 1Ω + 0.5Ω). For the same reasons as in the example in Figure 21, pattern (E) does not need to be used. Note that instead of adding an auxiliary coil next to the coil in question, the cross-sectional area of ​​the coil in question can be doubled, and the same effect can be obtained.

[0081] Figure 23 explains an example of operation switching using the embodiment of Figure 22 (i.e., an example of a five-coil element connection with an auxiliary coil). Each time the coil element connection pattern is switched, the motor takes on a different appearance, and the motors of each pattern form a single motor device. Therefore, each pattern has a maximum motor rotation speed. The graph of Figure 23 plots the TN characteristic lines of the motors of each pattern on a single T (torque)-N (rotation speed) characteristic diagram. When the coil element connection patterns of Figure 22 are matched at this time, the result is as follows.

[0082] In Figure 22 (A), all five coil elements are connected in series, so 5V ÷ 5V = 1 (this is also the case for Figure 21 (A)), which corresponds to the 1st mark on the vertical axis of the graph. This is the maximum rotation speed of the motor in pattern (A). Since pattern (A) requires all five coil elements to be connected in series, this is the motor with the smallest maximum rotation speed of all the motors contained in the motor device. In the following explanation of this application, the 1st mark is considered to be 20 km / h. In (B), all five coil elements are connected in parallel, so 1V is used, so 5V ÷ 1V = 5, which corresponds to the 5th mark on the vertical axis (i.e., 100 km / h). This is the maximum rotation speed of the motor in pattern (B). And since all five coils are connected in parallel, this is the motor with the highest maximum rotation speed of all the motors contained in the motor device. In (C), 2V is used, so 5 ÷ 2 = 2.5, which corresponds to the 2.5th mark on the vertical axis (50 km / h, the maximum rotation speed of the motor in pattern (C)). Since (D) is 3V, it becomes 5÷3=1.7, which corresponds to 1.7 scale marks on the vertical axis (34km / h, the maximum rotation speed of pattern (D)). And when it comes to (E), it becomes 4V, so it becomes 5÷4=1.25 (25km / h, the maximum rotation speed of the motor of pattern (E)).

[0083] In this case, the difference between the maximum RPM of 1 and the maximum RPM of 0 for the motor in pattern (A) is 1, the difference between the maximum RPMs of (A) and (D) is 1.7 - 1 = 0.7, the difference between the maximum RPMs of (D) and (C) is 0.8, and the difference between (C) and (B) is 2.5. In other words, the gap between (C) and (B) is significantly larger. This causes shock to both the driver and the motor device. If the maximum speed is not expected under normal circumstances, a limiter can be set before the maximum speed is reached. Therefore, the inventor proposes setting the limiter just before the RPM where this significantly larger gap occurs (for example, at 3.5 on the scale, which corresponds to 70 km / h). In this case, the scale width between the maximum RPM of pattern (C) and the RPM at the limiter position is 1.0, and the scale width from 0 to (A), (A) to (D), (D) to (C), and (C) to the limiter is approximately 1.0, reducing gear-shift shock for both the driver and the device. The range of these maximum rotation speeds should be approximately equal, and a motor with a coil element switching pattern should be selected so that the range is (1±0.5) times the maximum rotation speed when all coil elements are connected in series.

[0084] On the other hand, it is sufficient to select a motor with a coil element switching pattern that is within a range of (1±0.5) times the maximum rotation speed when all coil elements are connected in series, so motor patterns that do not meet this condition (for example, for pattern (E), the scale equivalent to the maximum rotation speed is 1.25, so the width between (A) and (E) is 0.25, and the interval between (E) and (D) is also 0.45, which falls outside the range of 1±0.5) can be unused. Because such fine switching can be omitted, switching control is simplified, and the switching intervals according to the maximum rotation speed are approximately uniform, reducing the sensory burden on the driver.

[0085] By the way, the horizontal axis of the graph in Figure 23 has a scale up to 6, and is connected by a characteristic line as shown in the figure, which is the effect of the auxiliary coil, which makes the slope of the TN characteristic gentler.

[0086] [Circuit configuration and short circuit prevention] The circuit used in the embodiment of the present invention will be explained with reference to Figures 24 and 25. Figure 25 shows the overall circuit configuration. If the series and parallel switching is performed by a mechanical selection operation, a short circuit will not occur. However, if a switching element or the like is used instead of a mechanical selection mechanism, a momentary short circuit may occur depending on the timing, so measures must be taken. One such measure is to use a clock. Specifically, the series gate and the parallel gate should not be ON (Hi) at the same time.

[0087] The gear switching operation means 30 is connected to the controller 31, and when a command signal from the gear switching operation means 30 is input to the controller 31, the command signal is input from the controller 31 to the shift register 32 as a command signal Sin (serial in).

[0088] When a command signal Sin is input, the shift register 32 outputs command signals from terminals Q0, Q1, and Q2, respectively. At this time, the shift register 32 adjusts the outputs from each terminal (Q0, Q1, Q2) by the action of the clock signal clk so that the shifts shown in FIG. 23 occur. Specifically, when Sin is L (Lo, the same applies hereinafter) and clk rises, Q0 becomes L, and when Sin is H (Hi, the same applies hereinafter) and clk rises, Q0 becomes H. On the other hand, in other cases, i.e., when there is no change in Sin, the signal state remains L or H regardless of the rising edge of clk. Q1 changes based on the Q0 signal. Specifically, when Q0 is L and clk rises, it becomes L, and when Q0 is H and clk rises, Q1 becomes H. If there is no change in the Q0 signal, the previous state, i.e., the L or H state, is maintained. Q2 changes based on the Q1 signal. Specifically, when Q1 is L and clk rises, it becomes L, and when Q1 is H and clk rises, Q2 becomes H. If there is no change in the Q1 signal, the previous state, that is, the L or H state, will be maintained, just like Q1.

[0089] The outputs from Q0 and Q2 are input to a NOR element 33, which outputs a command signal as EN (XNOR: exclusive NOR). In the NOR element 33, output of the command signal is permitted when the signals from Q0 and Q2 match, and output of the command signal is not permitted when the two signals do not match. Specifically, when the command signal output from Q0 is L and the output from Q2 is also L, the gate becomes H and output of the command signal is permitted. Similarly, when the output from Q0 is H and the output from Q2 is also Hde, the gate becomes H and output of the command signal is permitted. On the other hand, when the command signal output from Q0 is L and the output from Q2 is H, or when the output from Q0 is H and the output from Q2 is L, the gate becomes L and output of the command signal is not permitted.

[0090] The command signal output from Q1 in the shift register 32 is input to the AND element 35 via the NOT element 34, and is also input directly to the AND element 36. The output signal from the NOT element 34 is the opposite of the input signal (if the command signal output from Q1 is L, the output from the NOT element 34 is H, and if the command signal from Q1 is H, the output from the NOT element 34 is L), so the AND element 35 and the AND element 36 each receive an opposite command signal as the command signal from Q1.

[0091] The AND element 35 and the AND element 36 each output a command signal of H only when the command signal from Q1 and the output signal from the NOR element 33 simultaneously become H. As described above, the AND element 35 and the AND element 36 receive opposite signals (L or H) as the command signal from Q1, and therefore do not simultaneously output a command signal of H. Furthermore, because there is a difference in the switching timing of the command signals from Q0, Q1, and Q2 in the shift register 32, the switching timing of the output signal from the NOR element 33 and the switching timing of the command signal from Q1 do not coincide. Therefore, there is no risk that the switching timing of the command signals from the AND element 35 and the AND element 36 will coincide.

[0092] The outputs from the AND element 35 and the AND element 36 are input to blocks 37, 38, and 39, which constitute the circuits for each phase. Block 37 represents the U-phase block, block 38 represents the V-phase block, and block 39 represents the W-phase block. In blocks 37, 38, and 39, G1s, to which the command signal output from the AND element 35 is input, is the input terminal for the switching signal to the serial gate (series side), and G1p, to which the command signal output from the AND element 36 is input, is the input terminal for the switching signal to the parallel gate (parallel side). As described above, the command signals from the AND element 35 and the AND element 36 never coincide, which causes a discrepancy in the switching timing between L and H. Therefore, as shown in FIG. 24, there is no time when G1s and G1p are ON (Hi) at the same time, and no short circuit occurs. The numeral "1" in G1s and G1p indicates the number of the respective circuit units.

[0093] 25 and 26 show examples of circuit diagrams constituting blocks. While FIG. 25 illustrates circuits corresponding to the U, V, and W phases, and the example shown in FIG. 26 only illustrates an example of a circuit diagram for a block constituting the U phase, similar configurations apply to blocks constituting the V and W phases. For example, Lu1h becomes Lv1h for the V phase and Lw1h for the W phase, and Lu2h becomes Lv2h and Lw2h. Furthermore, Lu1l becomes Lv1l and Lw1l, and Vu becomes Vv and Vw, respectively. While the example shown in FIG. 26 illustrates switching elements and FET (field-effect transistor) elements 20a corresponding to the circuit section, the use of switching elements in implementing the present invention is not limited to FET elements.

[0094] In the above embodiment, the number of coil elements and the number of circuit sections are limited, but the number of coil elements and circuits may be increased or decreased, and the number of combinations of series and parallel connections of coil elements may be increased. Furthermore, in addition to increasing the number of combinations of coil connection configurations, appropriate rotation speeds and torques may be selected according to the application, and the combinations of coil element connection configurations may be limited. For example, when applying to applications such as power tools where increased rotation speed is desired rather than initial operating torque, it is possible to select and switch between combinations of coil elements that can achieve characteristic operation in the high rotation range, such as 4-parallel and 3-parallel.

[0095] In addition, in the above embodiment, the circuit unit 20 is shown mechanically to make it easier to understand the switching of the connection configuration of the coil elements, but the circuit unit 20 may also be given similar functions by a semiconductor chip.

[0096] In addition, in all of the above embodiments, the stator coil 18 is described as being cylindrical. However, the motor device according to the present invention can also include a configuration in which the stator coil is arranged in a disk shape, and is not limited to coreless motors but can be expanded to brushless motors including slotless motors. Although slotless motors are cored motors, they do not have iron core teeth, so they are similar to coreless motors in that they do not incur iron loss and have low inductance.

[0097] [When the number of coil elements is three] In addition, in the above explanation, it was explained that the number of coil elements is equalized when parallel connection is performed and that multiple-stage switching connection is possible, but as already explained in a modified embodiment, the number of coil elements constituting each phase may be either an even number or an odd number.

[0098] For example, as shown in Figures 27 to 29, if the number of coils in each phase that make up the stator coil 18 is three, it becomes possible to switch between a connection format in which three coil elements are connected in series (one parallel in the above embodiment: see Figure 27) and a connection format in which three coils are connected in parallel (three parallel in the above embodiment: see Figure 28), and other patterns such as the one shown in Figure 29 are also possible.

[0099] Figure 29 explains the relationship between the coils and switches when using three coil elements. Pattern (A) is all series (equivalent to Figure 27), resulting in a back-EMF of 3V. Pattern (C) is all parallel (equivalent to Figure 28), resulting in a back-EMF of 1V. Note that by disabling one coil element and setting the back-EMF to 2V, as in pattern (B), 1V, 2V, or 3V can be selected. Note that pattern (D) is 2P+1S, resulting in 2V and 1.5Ω, but for the same 2V requirement, pattern (B) should be used. Pattern (D) uses wire coil elements (not copper plate), which can potentially cause circulating currents due to slight phase misalignment between the two parallel coils caused by wire manufacturing. On the other hand, disabling one coil element, as in pattern (B), eliminates parallel use and eliminates circulating currents, improving efficiency. However, because a large current flows through the used coil elements in pattern (B), it is recommended to also take measures to prevent overheating. As can be seen from this figure, in this three-coil element embodiment, both ends of the middle coil element are connected to two switches each, meaning that a total of four switches are connected to one middle coil element.

[0100] [Possible switching patterns using four coil elements] Figure 30 shows the relationship between the coils and switches when four coils are used, summarizing the connection possibilities by adding patterns in which some coil elements are not used to the examples shown in Figures 1 to 3. The details of each pattern are as follows: Pattern (A) has all four coil elements in series, resulting in 4V and 4Ω. Pattern (B) has all four coil elements in parallel, resulting in 1V and 0.25Ω. Pattern (C) has 2P+2P, resulting in 2V and 1Ω. Pattern (D) has 2P+2S, resulting in 3V and 2.55Ω. Pattern (E) has 3P+1S, resulting in 2V and 1.33Ω. Pattern (F) has one coil element not used, resulting in 3S, resulting in 3V and 3Ω. Pattern (G) has one coil element not used, resulting in 2P+1S, resulting in 2V and 1.5Ω. Pattern (H) has two coil elements not used, resulting in 2S, resulting in 2V and 2Ω. Pattern (I) is 1S because three of the four coil elements are not used, resulting in 1V and 1Ω. Pattern (J) is 2P because two coil elements are not used, resulting in 1V and 0.5Ω, and pattern (K) is 3P because one coil element is not used, resulting in 1V and 0.33Ω. [Explanation of symbols]

[0101] 10....Motor device, 12....Housing, 12a....Bearing, 14....Rotating shaft, 16....Rotor, 16a....Permanent magnet, 16b....Inner yoke, 16c....Outer yoke, 18....Stator coil, 20(20U, 20V, 20W)....Circuit section, 22....Control section, 30....Gear switching operation means, 31....Controller, 32....Shift register, 33....NOR element, 34....NOT element, 35....AND element , 36...AND element, 37...U phase block, 38...V phase block, 39...W phase block, U1...first coil element, U2...second coil element, U3...third coil element, U4...fourth coil element, V1...first coil element, V2...second coil element, V3...third coil element, V4...fourth coil element, W1...first coil element, W2...second coil element, W3...third coil element, W4...fourth coil element.

Claims

1. A rotating electric machine having a permanent magnet, a stator, and a three-phase stator coil in a housing, A rotating electric machine characterized in that the stator coil of each phase has three or more coil elements, and by switching the connection between the coil elements, the pattern can be switched between series, parallel, a combination of series and parallel, or a combination of parallel and parallel, and switches for this switching are arranged between the coil elements, and for each of the coil elements except for the coil elements at both ends, both ends of the coil element are connected to two switches each, resulting in a total of four switches directly connected to the coil elements.

2. 2. The rotating electric machine according to claim 1, wherein the resistance of one of the plurality of coil elements is halved by connecting another coil element in parallel with the coil element or by doubling the cross-sectional area of ​​the coil.

3. 3. The rotating electric machine according to claim 1, wherein, of the coil element connection switching patterns assumed based on the number of coil elements to be used, a pattern in which all the coil elements are connected in parallel is not used.

4. The TN characteristics of the motor are determined for each coil element connection switching pattern assumed based on the number of coil elements used, and multiple motors with different TN characteristics are assumed.

4. A rotating electric machine according to claim 1, wherein the motors are selected so that the difference between the respective maximum rotation speeds of any two of the motors (including the difference from zero rotation speed in the case of the maximum rotation speed when all the coil elements are connected in series) is substantially similar (within a range of (1±0.5) times the maximum rotation speed when all the coil elements used are connected in series), and motor patterns that do not satisfy this condition are not used.

5. 5. The rotating electric machine according to claim 1, wherein the stator coil is cylindrical, and the rotating electric machine is a coreless type having a rotor with the permanent magnet positioned on an opposing surface of the stator coil and spaced apart from the stator coil.

6. 6. A rotating electric machine according to claim 1, wherein the parallel switching among the connection switching patterns between the coil elements enables multiple stages of switching in which the number of coil elements in a pair is changed depending on the number of coil elements constituting each phase.

7. 7. A rotating electric machine according to claim 1, wherein the switch is formed of one or more semiconductor elements.

8. 8. The rotating electric machine according to claim 1, further comprising a control unit that switches the switches so that the number of coil elements connected in series increases on the low rotation speed side relative to a predetermined rotation speed threshold, and the number of coil elements connected in parallel increases on the high rotation speed side.

9. 9. The rotating electric machine according to claim 5, wherein the stator coil has a deformation-resistant layer.

10. 10. The rotating electric machine according to claim 1, wherein the stator coil comprises three phases, U, V, and W.

11. 11. The rotating electric machine according to claim 1, wherein the stator coil is made of a litz wire.

12. An electric vehicle, characterized in that the rotary electric machine according to any one of claims 1 to 11 is used as a propulsion power source.

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