Rotating Electric Machines for Electric Vehicles

Abstract

A method for saving power in a power supply for a rotating electric machine is provided, which makes it possible to achieve energy saving effects in the power supply by devising measures on the motor side. [Solution] A motor 10 is connected to a battery 50. A driver 40 is interposed between the battery and the motor. A driver is a device that drives and controls a motor by passing current through it, and a driver is a device that controls the motor. A driver is an essential device for driving a brushless motor. A maximum current is set for each driver, and from the perspective of motor protection, an absolute maximum rating is set for safety, and the driver is used at a current value below that. A cable 60 is interposed between the driver and the battery, and a cable 70 is interposed between the driver and the motor, which are causes of copper loss. Note that reference numeral 80 denotes a coil connection pattern switching device, which in addition to having a group of switch functions for switching the motor coil connections, also sets the switching timing.

Description

Technical Field

[0001] The present invention relates to a power saving method for a power supply of a rotary electric machine for an electric moving body and a rotary electric machine for an electric moving body with a function of reducing the current consumption, and particularly to a power saving method for a power supply of a rotary electric machine suitable for application to an electric vehicle including a bicycle and a rotary electric machine with a function of reducing the current consumption.

Background Art

[0002] Conventionally, as technologies aiming at energy-saving effects related to rotary electric machines, various control methods such as the use of inverters, so-called energy-saving technologies, have been proposed. In particular, for those equipped with a battery like an electric vehicle, it is expected to increase the driving distance (increase the cruising distance) when driving the motor that is the power source. Moreover, different from the power supply of a building, the battery mounted on a moving body must supply power within the moving body and is limited. Therefore, extending the life of the battery is important, and thus the development of the battery itself and the improvement of the control method of the motor have been made.

[0003] However, these proposals lacked the perspective of changing the basic structure and basic performance of the motor itself.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] To reduce power consumption in electric vehicles equipped with batteries, various methods have been proposed, including improvements to refrigerant circulation (Patent Document 1), control of equipment associated with the motor (inverter, generator, etc.) (Patent Document 2), raising the temperature of the battery (Patent Document 3), and stopping the supply of power from the battery to the motor control device depending on the estimated temperature of the motor (Patent Document 4).

[0006] While all of these methods contribute to power saving, extending battery life and increasing driving range are essential issues for the widespread adoption of electric vehicles. The inventors have therefore been investigating whether there are other methods for saving power and extending driving range.

[0007] Therefore, the present invention aims to achieve energy-saving effects on the power supply through improvements on the motor side. Furthermore, it aims to extend the driving range (cruising range) of the battery of an electric mobile device. [Means for solving the problem]

[0008] To achieve the above objectives, the power saving method for a rotating electric machine for an electric mobile body according to the present invention is characterized by the following features. (1) A method for saving power to a rotating electric machine for an electric mobile body, comprising a power supply, a driver, a first wiring path from the power supply to the driver, a rotating electric machine, and a second wiring path from the rotating electric machine to the driver, wherein the rotating electric machine is replaced with a rotating electric machine that has three or more coils (of the same specifications) for each of the multiple phases, and the connection between the coils of each phase in the middle of the second wiring path is selected and switched to at least one of the following patterns: (a) all in series, (b) all in parallel, or (c) a series-parallel connection in which a combination of parallels is connected in series, thereby changing the current used by the power supply, the coil connection at startup is set to (a) to achieve the maximum torque state, the coil connection at the maximum speed state is set to (b) to achieve the minimum torque state, the series-parallel connection of (c) is used in the intermediate speed stage, the coil connection automatically returns to (a) as the speed decreases on an uphill slope, and the rotation speed changes in stages on a downhill slope while braking is applied using (c).

[0009] (2) A method for saving power to a power supply for a rotating electric machine for an electric mobile body, comprising a power supply, a driver, a first wiring path from the power supply to the driver, a rotating electric machine, and a second wiring path from the rotating electric machine to the driver, wherein the rotating electric machine has three or more coils for each of the multiple phases and incorporates substantially multiple motors of different efficiencies that share coils by switching the connection between the coils, and the switching pattern of the connection between the coils is selected from at least (a) all in series, (b) all in parallel, and (c) a series-parallel connection in which a combination of parallels is connected in series, thereby setting the coil connection to (a) at startup to achieve the maximum torque state, setting the coil connection to (b) at the maximum speed state to achieve the minimum torque state, setting the series-parallel connection to (c) at the intermediate speed stage, automatically switching to (a) as the speed decreases on an uphill slope, and selecting a coil connection such that the rotation speed changes in stages on a downhill slope while braking, thereby automatically selecting a motor with high motor efficiency at any given rotation speed according to the load and reducing the power supply current consumption.

[0010] (3) In (1) or (2) above, the power source is a battery, and by selecting, the range of an electric vehicle is extended by switching between a stage with a small torque constant and a stage with a large torque constant.

[0011] (4) The rotating electric machine is a coreless motor having a rotor equipped with a non-rotating cylindrical stator coil body built into a motor housing and permanent magnets positioned on the opposite surface of the stator coil body at a distance from it. The cylindrical stator coil body is made up of multiple phases, each consisting of three or more coils, and each coil is of the same specification, wound with insulated conductors. One end of the cylindrical coil body is fixed inside the motor and the other end is a free end, with a reinforcing ring fitted to the free end and a reinforcing layer attached to the circumferential surface of the cylindrical stator coil body.

[0012] (5) In any of the above (1) to (4), (d) a pattern is further added as a switching pattern for the connection between coils, in which one more coil or two or more series-connected coils are connected in series to the parallel combination of (b) or (c).

[0013] (6) In (5) above, one coil is attached in parallel to one coil that is connected in series in (d) above (hereinafter referred to as "supplementary coil" in this application. A supplementary coil is a coil that is connected in parallel to a specific coil that is added in series in (d) above, separate from the parallel connections in (b) and (c) above).

[0014] (7) Set the entire parallel section of (b) and (c) or (c) to be a limiter for the speed of the motorized mobile body.

[0015] (8) The number of coils in each phase shall be six, and the switches provided between each coil shall be reduced to form a series section of coils without switches, thereby making the all-parallel pattern of (b) unused, and switching to a total of three patterns: the all-series pattern of (a), and as (c), 3 series 2 parallel (3S2P) and 2 series 3 parallel (2S3P).

[0016] (9) The number of coils in each phase shall be 12, and the switches provided between each coil shall be reduced to form a series section of coils without switches, thereby making the all-parallel pattern of (b) unused, and switching to a total of four patterns: the all-series pattern of (a) and three patterns of (c) 2P6S, 3P4S, and 4P3S.

[0017] Furthermore, the rotating electric machine for electric mobile bodies of the present invention is characterized by any of the following: (10) A rotating electric machine for an electric mobile body, which is incorporated into a device comprising a power supply, a driver, and a first wiring path from the power supply to the driver, and is connected to the driver by a second wiring path, wherein the rotating electric machine has three or more coils for each phase of a plurality of phases, and substantially multiple motors of different efficiencies are built in such a way that they share coils by switching the connection between the coils, and the switching pattern of the connection between the coils is selected from at least (a) all in series, (b) all in parallel, and (c) a series-parallel connection in which a combination of parallels is connected in series, thereby setting the coil connection to (a) at startup to achieve the maximum torque state, setting the coil connection to (b) at the maximum speed state to achieve the minimum torque state, setting the coil connection to (c) at intermediate speed stages to achieve the series-parallel connection, automatically setting to (a) as the speed decreases on an uphill slope, and setting the coil connection to (c) on a downhill slope to change the rotation speed in stages while braking, thereby having a current reduction function that automatically selects a motor with high motor efficiency at any given rotation speed according to the load.

[0018] (11) The power source is a battery, and it has a function to reduce the current used by the power source in accordance with the switching between a stage with a small torque constant and a stage with a large torque constant, thereby saving power to the electric vehicle and extending its range.

[0019] (12) The rotating electric machine is a coreless motor having a rotor equipped with a non-rotating cylindrical stator coil body built into a motor housing and permanent magnets positioned on the opposite surface of the stator coil body at a distance from the stator coil body, the cylindrical stator coil body is made up of multiple phases, each consisting of three or more coils, each coil being of the same specifications with insulated wire wound around it, one end of the resulting cylindrical coil body is fixed inside the motor and the other end is a free end, a reinforcing ring is fitted to the free end and a reinforcing layer is attached to the circumferential surface of the cylindrical stator coil body.

[0020] (13) As a switching pattern for coil connection, further, (d) a pattern in which one more coil or two or more serially connected coils are serially connected to the parallel combination of (b) or (c) is added.

[0021] (14) For one coil serially connected in (d), one coil is attached in parallel.

[0022] (15) Between all the parallel connections of (b) and (c), or make (c) the limiter of the speed of the electric moving body.

[0023] (16) The number of coils in each phase is six. By thinning out the switches provided between the coils to form a coil series part that does not pass through the switches, the pattern of all parallel connections of (b) is made unused, and the pattern of all series connections of (a) and three patterns of 3S2P and 2S3P as (c) are switched.

[0024] (17) The number of coils in each phase is twelve. By thinning out the switches provided between the coils to form a coil series part that does not pass through the switches, the pattern of all parallel connections of (b) is made unused, and the pattern of all series connections of (a) and four patterns of 2P6S, 3P4S, and 4P3S as (c) are switched.

[0025] Furthermore, the following aspects of the present invention are also effective. (18) Making some coils unused, changing the thickness of some coils, or attaching additional coils in parallel to some coils are also within the scope of the present invention. However, unless otherwise specified in the present specification, each coil shall have substantially the same specifications.

[0026] (19) The case where elements, devices, and apparatuses other than wiring are interposed on the first wiring path and the second wiring path is included (hereinafter the same).

[0027] (20) The motor is equipped with a motor torque constant selection switch, which is selected for a lower torque constant for desired high-speed rotation, and selected for a higher torque constant when the desired high-speed rotation is not required, thereby suppressing the motor current in the section where high-speed rotation is not required.

[0028] (21) The coil connection selection device is a device that automatically determines and executes the timing of the switch.

[0029] (22) A rotating electric machine in which substantially three or more motor functions with different battery currents at any torque constant are created within a single motor by coil switching, wherein the switching mechanism for each motor function switches the current used in each motor function to a rotational speed corresponding to a torque determined within the range of the maximum current.

[0030] (23) A single rotating electric machine having substantially three or more motor functions by having three or more motors with different battery currents at an arbitrary torque constant share and select to use each other's coils, wherein the mechanism for selecting the coils switches to a rotational speed corresponding to the current used in each of the motors.

[0031] (24) A coreless rotating electric machine comprising a housing, a cylindrical, non-rotating stator coil body, and a rotor equipped with permanent magnets positioned spaced apart from the stator coil body and on the opposite surface of the stator coil body, wherein the stator coil body consists of a plurality of phases, each phase is composed of a plurality of coils, and the circuit unit includes a coil connection type selection circuit that allows selection of the connection type of the coils constituting each phase to a series type, a parallel type, and a plurality of types between parallel types, and a single rotating electric machine in which a plurality of motors can be formed depending on the combination of coils, the circuit unit uses one or more semiconductor elements to change the number of coils in a set according to the number of coils constituting each phase, and selects the coil connection type such that the number of coils connected in series is increased on the low rotation side and the number of coils connected in parallel is increased on the high rotation side for a predetermined rotation speed, and switches to a rotation speed corresponding to a torque constant in which the current used in each motor is reduced.

[0032] (25) A method for operating a motor characterized in that a single rotating electric machine contains substantially three or more types of motors M1, M2, ... Mn (where n is an integer, the larger n is, the greater the TI characteristic; the same applies hereinafter) with different motor efficiency characteristics due to different TI characteristics, and the multiple motors selectively share the coils used so that one of the motors can be selected and used within a single rotating electric machine, the TI characteristics have a substantially direct relationship between the motor operating current value (I) and torque (T), the TN characteristics corresponding to each TI characteristic have a substantially inverse relationship between the rotational speed (N) and torque (T), the current value of the TN characteristic and the torque at the maximum current value derived from the driver are T1, T2, ... Tn (where T1, T2, ... n correspond to M1, M2, ... Mn) due to the difference in the TN characteristics, the motor rotates at a rotational speed corresponding to a torque lower than T1, T2, ... Tn, and for the same torque value of each motor, the motor with the larger n is selected and used, thereby selecting the motor with higher motor efficiency at the same rotational speed. In this case, it is desirable to set T2 to be 1 / 2 of T1, T3 to be 1 / 4 of T1, ... Tn to be (1 / 2)^(n-1).

[0033] (26) A method for operating a rotating electric machine in which three or more motors with different maximum rotational speeds share multiple coils, and by switching the connections between these coils, the machine can effectively switch to three or more motors with different rotational speed specifications, wherein if the rotational speed is the same (or the torque is the same), the machine automatically switches to the motor with the lower rotational speed specification.

[0034] (27) The timing of the automatic switching of coil connections in each of the above rotating electrical machines shall be selected from one or a combination of the rotational speed, torque (motor current), and motor voltage.

[0035] (28) As a coil configuration connection pattern for each of the above rotating electrical machines, there is a configuration in which one or more coils are connected in series to a parallel arrangement of multiple coils. In this application, the entire coil section of a motor is referred to as a stator coil, and the individual coils that make up the stator coil are simply referred to as coils.

[0036] Incidentally, regarding mixed series and parallel patterns, from the perspective of general motor knowledge, the continuous current is determined by the weakest coil, which lowers the overall rated current. Furthermore, it would be desirable to prevent excessive heat generation in the series coil section. Therefore, even before discussing the switching of coil connections, a mixed series and parallel pattern for multiple coil connections within a motor would likely not be conceivable to those skilled in the art. However, the inventor of this application actively considered adopting a mixed series and parallel pattern. By using this pattern, the number of coils in each phase can be odd, and the variations in switching are greatly increased. Therefore, when applied to moving objects such as electric vehicles, fine control (stage switching) and smooth switching become possible.

[0037] Odd-numbered coils cannot be combined with the same number of parallel coils; they can only be combined with parallel coils of different numbers or with one or more series coils connected to the parallel coils. However, the inventor decided that since the current flowing through the coil is determined by the driver, it is sufficient to flow the current that matches the weakest coil, and instead prioritized increasing the number of coil switching patterns to enable finer switching.

[0038] Furthermore, even if excessive heat generation is a concern for the coil considered to be the weakest, as mentioned above, (1) by combining a predetermined number of coils made by winding wire at high density to form a cylindrical coil (i.e., a type without iron core teeth, like a coreless motor or slotless motor), even if some wire coils generate excessive heat, the heat is diffused to adjacent wire coils, thus suppressing excessive heat generation. Heat generation can also be suppressed by other cooling means. In addition, (2) by adding a dummy coil (referred to as a supplementary coil in this application) in parallel with the coil considered to be the weakest part (see, for example, Figures 43 and 44), the resistance can be distributed and heat generation can be suppressed. In other words, since the imbalance in the heat-generating parts can be resolved, the focus was instead on increasing the switching points, and the adoption of an odd number of coils and a mixed series / parallel pattern does not exist in conventional thinking. [Effects of the Invention]

[0039] According to the power saving method for a rotating electric machine for electric mobile vehicles having the above-described characteristics, energy saving effects on the power supply can be achieved through improvements on the motor side. Furthermore, according to the rotating electric machine for electric mobile vehicles having the above-described characteristics, the driving range (cruising range) of the electric mobile vehicle's battery can be extended. [Brief explanation of the drawing]

[0040] [Figure 1] This is a system diagram of an embodiment to which the present invention is applied. [Figure 2] This is a side cross-sectional view showing the schematic configuration of a motor according to an embodiment of the present invention. [Figure 3] This figure shows an example of a cross-sectional configuration of a stator coil body applied to the present invention. [Figure 4] Figure 3 is an explanatory diagram illustrating examples of combinations of multiple coils that make up the stator coil assembly. [Figure 5] These are TI and TN characteristic curves for three motors with different efficiencies. [Figure 6] This is a measured diagram illustrating the selection of motors with different efficiencies at high, medium, and low speeds. [Figure 7] This is an illustrative diagram comparing the characteristics of three motors with different efficiencies. [Figure 8] This figure shows a specific example of operation switching when a 3-stage motor is applied to a vehicle (relationship between rotational speed change and connection switching). [Figure 9] This figure shows a specific example of operation switching when a 3-stage motor is applied to a vehicle (hysteresis relationship). [Figure 10] This figure shows a specific example of operation switching when a 3-speed motor is applied to a vehicle (relationship between speed change and connection switching). [Figure 11] This figure shows a specific example of operation switching when a 3-stage motor is applied to a vehicle (relationship between changes in road surface incline and connection switching). [Figure 12] This is a coil connection pattern diagram for an embodiment of the present invention where there are five coils for each phase (5 coils). [Figure 13] Figure 12 is an image diagram of the switch arrangement used for switching coils in the coil pattern. [Figure 14] This is a connection pattern diagram for a configuration with four coils. [Figure 15] This is a connection pattern diagram for a configuration with three coils (3 coils). [Figure 16] This is a connection pattern diagram for a configuration with 6 coils. [Figure 17] This is a connection pattern diagram for a configuration with 8 coils. [Figure 18] Continuing from Figure 17, this is a connection pattern diagram with 8 coils. [Figure 19] This figure shows an example configuration of a control unit that outputs a command signal to a circuit unit using switching elements. [Figure 20] This diagram shows the relationship between the clock and the Lo and Hi values ​​of various command signals when the circuit section is composed of switching elements. [Figure 21] This diagram shows examples of the circuits of the blocks that make up each phase. [Figure 22]Figure 19 is a detailed explanatory diagram of the control unit that generates dead time and outputs a command signal. [Figure 23] This shows an FET switching circuit, and is a detailed diagram of the U-phase block indicated by reference numeral 37 in Figure 22. [Figure 24] This is an explanatory diagram illustrating the overall circuitry for coil switching operation when the present invention is applied to an electric motorcycle. [Figure 25] This is a circuit diagram used to achieve the battery power saving effect of the present invention. [Figure 26] This is a characteristic diagram illustrating an example of the battery power saving effect of the present invention. [Figure 27] This figure shows the circuit configuration of the stator coil in the motor according to the first embodiment. [Figure 28] This graph shows the relationship between torque and rotational speed, and between torque and current, when the connection method of the coils constituting the stator coil is switched. [Figure 29] This graph shows the changes in characteristics when operating a motor by switching the connection method of the coils that make up the stator coil. [Figure 30] This graph shows the changes in output characteristics when operating a motor by switching the connection method of the coils that make up the stator coil, and the zones for switching according to the situation. [Figure 31] This figure shows the circuit configuration of the stator coil in the motor according to the second embodiment. [Figure 32] This graph shows the characteristic changes when the motor is operated by switching the connection method of the coils constituting the stator coil body in the motor according to the second embodiment. [Figure 33] This diagram shows an application configuration with 12 coils and 5 circuit sections per phase. [Figure 34] This is a cross-sectional view showing an example of a coil arrangement when 12 coils are used. [Figure 35] This diagram shows an example circuit for a 6-speed motor. The area enclosed by the dashed line A in the diagram is shown in a magnified view. [Figure 36]This is an explanatory diagram of an indicator for automating the timing of coil connection switching used in the present invention. [Figure 37] These are TI-TN characteristic curves for three types of motors used in the rotating electric machine of this invention. [Figure 38] This figure shows an example circuit when the stator coil is configured with two phases. [Figure 39] This is an exploded view showing an example of a two-phase stator coil assembly where the coils of each phase are connected in series. [Figure 40] This is an exploded view showing an example of a two-phase stator coil assembly where the coils of each phase are connected in parallel. [Figure 41] This diagram shows an example circuit when the stator coil is configured with five phases. [Figure 42] This is an explanatory diagram illustrating an example of the application of the coil switching used in the present invention. [Figure 43] This is an explanatory diagram of a coil pattern, showing yet another example of coil connection. [Figure 44] Figure 43 is an explanatory diagram showing variations in connection switching for the example shown. [Figure 45] Figure 44 shows the TN characteristic diagram based on an example of connection switching. [Figure 46] This is an explanatory diagram of a coil pattern, showing yet another example of coil connection. [Figure 47] This is an explanatory diagram of a coil pattern, showing yet another example of coil connection. [Figure 48] Figure 47 shows the TN characteristic diagram based on an example of connection switching. [Figure 49] This is an illustrative diagram of a cylindrical coil reinforcement measure for a coreless rotating electric machine used in the present invention. [Figure 50] This is an explanatory diagram of another embodiment of the control system diagram of the present invention. [Modes for carrying out the invention]

[0041] The following describes in detail, with reference to the drawings, an embodiment of the power saving method for a rotating electrical machine and a rotating electrical machine with a current reduction function according to the present invention. In the following description, for example, if the total number of coils is 4, 4P (4 parallel) means that 4 coils are connected in parallel, 2P (2 parallel) means that 2 coils are connected in parallel (also written as 2P+2P), and 4S (series) means that 4 coils are connected in series. The number presented before S indicates the number of coils arranged in series.

[0042] [Explanation of the principle] The inventors have discovered that by switching (selecting) between series, parallel, multiple parallel patterns, and mixed series-parallel patterns, the variations in switching are significantly increased, enabling smoother switching, while also providing energy-saving effects, reducing power consumption, and extending the range when driving rotating electrical machinery. The inventors believe there are two reasons for these effects.

[0043] [Assumed reason 1] The total power consumption supplied to the system from a power source such as a battery can be broadly divided into the power consumed within the motor, such as mechanical losses, the power consumed within the switching circuit, the power consumed by the wires from the motor driver to the switching circuit, the power consumed by the driver, and the power consumed by the wires from the power source to the driver, in addition to the power consumed as output from the motor shaft.

[0044] As a concrete example, consider a motor with a torque constant kt of 2 Nm / A in a series connection and 0.5 Nm / A in a parallel connection. In this case, to obtain an output of 100 Nm, a motor current of 50 A is required in the series connection and a motor current of 200 A is required in the parallel connection. For example, the conductor of the wire from the driver to the switching circuit has a diameter of 8 mm (cross-sectional area of ​​50 mm²), the same as the thickness of a cigarette. 2 If a 3m length of wire is used, the cable resistance is estimated to be approximately 1mΩ. Also, if the contact resistance at the connections between the driver and the cable, and between the cable and the switching circuit, is estimated to be 1mΩ, the cable loss in series connection is approximately 15W (3 phases × 2mΩ × 50A) in total for all three phases.2 ) can be estimated. On the other hand, the cable loss when connected in parallel is approximately 240W (=3 phases × 2mΩ × 200A). 2 ) This results in approximately 225W more power loss compared to when connected in series.

[0045] If an FET with a drain-source resistance of, for example, 0.5 mΩ in the ON state is used as the switching element in a switching circuit, the power loss in the switching circuit when connected in series is approximately 23 W (= 3 phases × 6 × 0.5 mΩ × 50 A). 2 It can be estimated that... Therefore, even after subtracting the losses in the switching circuit, a loss reduction of approximately 200W can be expected. Furthermore, the power consumed by the FETs in the driver circuit can also be expected to decrease as the motor current decreases. However, the switching of the FETs in the driver circuit is far more frequent than that of a relay-type switching circuit. For this reason, the losses in the driver are significant.

[0046] As described above, the switching circuit allows for high-speed rotation by switching to a setting that reduces the motor torque constant. Conversely, in situations where high torque is required, the switching circuit can be switched to a setting that increases the motor torque constant, thereby reducing the motor current and lowering the overall power consumption of the system.

[0047] As described above, the present invention is particularly effective when applied to systems where the cable length between the motor and driver is long, when the maximum current is large (such as in electric motorcycles), when the motor capacity is large, or when the time required to generate instantaneous maximum torque is short (such as in wheelchairs).

[0048] [Assumed reason 2] It is thought that, given the same rotational speed or torque, automatically selecting the motor with lower current efficiency can result in energy savings equivalent to the difference in current. In short, it involves switching between multiple motors with different current efficiencies depending on the usage situation, essentially taking advantage of the best features of each motor.

[0049] Motors are generally categorized into low-speed and high-speed types. The induced voltage generated by the motor's rotation allows low-speed motors to achieve high torque but not sufficient torque at high rotational speeds. High-speed motors achieve high rotational speeds but require a large current, leading to current limitations and preventing them from producing the necessary high torque. If the motor's rotational speed continues to increase, the induced voltage will either exceed the battery voltage or the current will stop flowing altogether.

[0050] Therefore, expanding the output range has been proposed for some time. In particular, for electric vehicle systems, a wide output range, high efficiency, compact size, and lightweight design are key challenges. Output, which is the product of torque and rotational speed, involves a trade-off relationship between torque and rotational speed, making it difficult to ensure high output from high speed to low speed range. Therefore, the inventor has tried to utilize (take the best of) multiple motors with different current efficiencies (= different maximum rotational speed specifications).

[0051] The explanation will be given using Figures 5 and 6, which illustrate three types of motors with different maximum rotational speeds as examples. Figure 5 shows characteristic diagrams of three types of motors, with the premise that by using four coils and switching between them, essentially three types of motors with different motor efficiencies can be provided as a single motor.

[0052] In this diagram, the current limit is 8A, and the motor uses 4 coils. Three motor configurations are possible: all 4 coils in series (4S-1P), all 4 coils in parallel (1S-4P), and two sets of 2 coils in parallel (2S-2P). If the horizontal axis of the graph is torque (T), the left vertical axis is rotational speed (N), and the right vertical axis is current (I), the TI and TN characteristics of each motor configuration are shown in the figure above. The switching of each characteristic is performed based on rotational speed, torque, and efficiency, with the switching based on efficiency illustrated in Figure 6. We will consider which motor configuration is appropriate for each of the following cases: low rotation (1000 rpm, (a)), medium rotation (2500 rpm, (b)), and high rotation (5000 rpm, (c)).

[0053] At low RPMs, if the torque is 2 N·m or less, all three configurations are possible: 1S-4P (4 coils in parallel), 2S-2P (2 coils in parallel), and 4S-1P (4 coils in series). In this case, 4S-1P is the most efficient and requires the lowest motor current, so it is selected. When the torque is between 2 N·m and 4 N·m, both 2S-2P and 4S-1P are usable, but 4S-1P is the most efficient and requires the lowest motor current, so it is selected. When the torque is between 4 and 8 N·m, only 4S-1P is possible. Therefore, at low RPMs, the 4S-1P (4 coils in series) configuration, which offers the highest motor efficiency, is selected.

[0054] For medium RPMs, when the torque is 2 N·m or less, two options are available: 2S-2P and 1S-4P. However, 2S-2P is more efficient and requires less motor current, so it is the better choice. For torques between 2 N·m and 4 N·m, only 2S-2P is suitable. Therefore, 2S-2P is the best choice for medium RPMs.

[0055] At high rotational speeds, only 1S-4P motors with a torque of 2 N·m or less can be used. Therefore, selecting a motor pattern that can be used in the torque range appropriate for each rotational speed means choosing the one with higher motor efficiency, which in turn allows for the selection of a motor with lower current consumption, leading to current savings.

[0056] Figure 7 shows the efficiency measurement results for three types of motors with different efficiencies. For the same torque, motors with lower rotational speed specifications (capacity) consume less energy and are more efficient. Furthermore, regardless of high or low rotational speed, if used at the same rotational speed, motors with lower rotational speed specifications consume less energy and are more efficient. If a high-speed motor is used in the low-speed range, switching to a low-speed motor would be more energy-efficient, and it is estimated that this would allow for longer driving distance and time during motor operation.

[0057] However, simply lining up motors would result in a large volume being occupied by the motors. Therefore, the decision was made to share the coils used by each motor and switch between multiple motors by switching the coils.

[0058] [Motor and coil configurations suitable for use in the present invention] First, the basic configuration of the motor 10 according to this embodiment will be described with reference to Figures 2 to 4. The motor 10 according to this embodiment is a so-called coreless motor, consisting of a housing 12, a rotating shaft 14, a stator coil body 18, and a rotor 16. The housing 12 is an element that constitutes the outer shell, and houses the rotating shaft 14, the stator coil body 18, and the rotor 16 in its internal space. The rotating shaft 14 is positioned to penetrate the housing 12 and is rotatably supported by a bearing 12a provided at the intersection with the housing 12.

[0059] The stator coil body 18 is configured to form a cylindrical shape by a group of coils divided into multiple phases (in this embodiment, three phases: U phase, V phase, and W phase) (each coil is connected in groups of one or more to form one coil, and the same number of such coils are provided for each phase), as schematically shown in Figures 3 and 4. The U phase, V phase, and W phase that constitute the stator coil body 18 each consist of multiple coils that constitute poles. In the configuration shown in Figure 3, each phase is divided in half (i.e., into two equal parts) and configured to consist of a first coil U1, a second coil U2, a first coil V1, a second coil V2, a first coil W1, and a second coil W2. As a more specific example, the phase that constitutes the inner cylindrical coil body is the U phase, the phase located radially outside the inner cylindrical coil body is the V phase, and the phase located further outside the V phase is the W phase, with a first coil (U1, V1, W1) and a second coil (U2, V2, W2) defined for each phase. Note that arranging the phases from the inside out as U-phase, V-phase, and W-phase is just one example; other order and overlapping configurations are also acceptable. In Figure 3, each phase is sequentially offset by approximately 1 / 3 of the electrical angle in the circumferential direction. A stator coil body 18 with this configuration is supported at one end face by a stator (housing 12 in the example shown in Figure 2), which is a fixed member.

[0060] Here, for the sake of simplicity, I stated that the phases are "shifted approximately 1 / 3 each in the circumferential direction," but strictly speaking, the U-phase, V-phase, and W-phase are shifted by 120° in electrical angle. In terms of mechanical angle (actual angle), in the case of 2 poles, the V-phase is shifted 120° relative to the U-phase, and the W-phase is shifted 240°. In the case of 4 poles, the V-phase is shifted 60° or 240° relative to the U-phase, and the W-phase is shifted 120° or 300°. In the case of 6 poles, the V-phase is shifted 40°, 160°, and 280° relative to the U-phase, and the W-phase is shifted 80°, 200°, and 320° relative to the U-phase. In the case of 8 poles, the V-phase is shifted 30°, 120°, 210°, and 300° relative to the U-phase, and the W-phase is shifted 60°, 150°, 240°, and 330° relative to the U-phase. Thus, the shifts continue according to the rules for 10 poles, 12 poles, and so on. The U, V, and W phases are shifted by 120° each in electrical angles, but when expressed in mechanical angles, the angle of shift changes depending on the number of poles, so Figure 4 is a schematic representation.

[0061] The rotor 16 also has a cylindrical outer yoke 16c, an inner yoke 16b, and a permanent magnet 16a, with one end face connected to the rotating shaft 14. The outer yoke 16c is located on the outer circumference side (radially outward side with the center of the cylinder as the base point) of the stator coil body 18, and the inner yoke 16b is located on the inner circumference side of the stator coil body 18. In the motor 10 according to this embodiment, the permanent magnet 16a is configured to be located inside the outer yoke 16c and on the surface opposite to the stator coil body 18. A coreless motor with such a configuration can keep its self-inductance small because the stator coil body 18 does not have an iron core. The fact that the inductance can be small because there is no iron core makes it effective to apply the present invention to slotless motors as well.

[0062] Furthermore, in a motor 10 with this configuration, when constructing the stator coil body 18, Litz wire is used for the windings and the shape is formed by coating with an insulating layer. Litz wire is composed of multiple conductive wires bundled together, and the outer circumference of each conductive wire is covered with an electrically insulating layer (such as enamel). In addition, an outer sheath layer of fibrous material such as glass fiber may be provided on the outer circumference of the bundled conductive wires 18a, and this configuration allows for firm shape maintenance.

[0063] The winding method illustrated in Figure 4 is a schematic representation for illustrative purposes only and is not strictly followed. In the winding methods disclosed in the inventors' patents No. 6989204 and 6948748, it is also effective to replace the coil with a bundle of one or more Litz wires. In this case, even if excessive heat distribution occurs in parts of the coil due to a mixture of parallel and series sections, the heat is diffused by the closely packed coil wires, and excessive localized heat generation is suppressed.

[0064] [Concept of the overall system to which the present invention applies] Figure 1 illustrates the overall system concept of the present invention. Since the present invention aims to conserve energy (conserve power) in the power supply, the rotating electric machine (motor 10) is connected to the power supply (battery 50) of the mobile unit. A motor driver (hereinafter sometimes simply referred to as "driver") 40 is interposed between the battery 50 and the motor 10. The driver 40 is a device that drives and controls the motor 10 by supplying current, and is essential for driving a brushless motor (including rotational speed, speed control, voltage control, etc.). A maximum current is defined for each driver 40, and for safety reasons from the standpoint of motor protection, an absolute maximum rating is defined, and the driver is used with a current value below this. A cable 60 is interposed between the driver 40 and the battery 50, and a cable 70 is interposed between the driver 40 and the motor 10, which contribute to copper loss. Reference numeral 80 denotes an automatic coil switching device, which, in addition to the switch function group for switching the connection of the motor 10's coils, also sets the switching timing. Furthermore, since the driver 40 can set the current flowing through the motor (coil), even if there are coils that become weaker due to a mix of series and parallel connections, the driver's current setting can be adjusted based on the weaker coil.

[0065] [Application to electric mobile devices] The inventors envision electric mobile devices incorporating the system shown in Figure 1, such as electric motorcycles, wheelchairs, electric vehicles, and AGVs (automated guided vehicles). However, the invention is not limited to passenger vehicles like AGVs and drones, nor is it limited to land vehicles like drones and ships. The operation switching of the electric mobile device will be illustrated below using Figures 8 to 11. Motor 10 is not limited to a coreless motor; a motor with an iron core can also be used, and the changes in rotational speed and load can be seen in the case of electric lawnmowers equipped with rotating blades. However, as will be explained in a separate section, coreless motors and slotless motors that do not use iron core teeth are preferable because they allow for smaller inductance. The circuit diagrams used in the following examples will be described in a separate section.

[0066] As can be seen from Figures 8 and 9, at startup (when the vehicle starts), the rotation speed is low and initial torque is needed to move the vehicle, so the coil connection is set to L (low), that is, in series (1 parallel. If there are 4 coils, all 4 coils are in series, i.e., 4S). After starting, for example, when the rotation speed of motor 10 reaches 700 rpm (equivalent to 30 km / h), it automatically switches from L to 2 parallel (if there are a total of 4 coils, then 2P + 2P). In this example, the connection is set to switch automatically depending on the rotation speed of motor 10. Therefore, if the vehicle speed is further increased, for example, when the rotation speed of motor 10 reaches 1400 rpm (equivalent to 60 km / h), it switches to 4 parallel.

[0067] Furthermore, if the vehicle speed is increased to 100 km / h (for example, motor 10's rotation speed is 2000 rpm) with 4 parallel (all four coils in parallel), when it enters a slight uphill slope (inclination angle α), the load on motor 10 increases, causing the rotation speed to automatically decrease and the speed to drop. For example, when the rotation speed drops to around 1167 rpm (equivalent to 50 km / h: 5 / 6 of 1400 rpm), it automatically switches to 2 parallel.

[0068] Next, when the slight incline turns into a steep slope (inclination angle β), the load on motor 10 increases further, the rotational speed decreases, and the speed drops. For example, when the rotational speed drops to around 467 rpm (equivalent to 20 km / h: 2 / 3 of 700 rpm), it automatically switches to series (1 parallel, i.e., 4S:L). Note that the settings for 50 km / h (1167 rpm), 20 km / h (467 rpm), etc. when traveling uphill correspond to the hysteresis fluctuation range (see Figure 9).

[0069] When traveling uphill, the vehicle gradually accelerates, and when it reaches approximately 30 km / h (700 rpm) on a flat road, the motor 10's connection configuration automatically switches to 2 parallel (2P+2P). Furthermore, when it accelerates further on a flat road to 60 km / h (1400 rpm), it switches to 4 parallel (4P), allowing it to accelerate up to approximately 100 km / h (2000 rpm). Up to this point, the coil connection pattern switching device 80 automatically controls the motor's rotational speed as it increases.

[0070] In contrast, when entering a downhill slope (for example, a steep slope with an incline angle γ), the automatic coil switching device 80 is switched based on a command signal from the rider, and the motor 10 is controlled to apply braking using its rotational resistance (= regenerative braking: so-called engine braking). Automatic control and manual control can be combined in this way. For example, on a steep slope, the speed is gradually reduced in the 4P state to about 60 km / h (1400 rpm). Then, when the downhill slope becomes gentler (for example, an incline angle θ), it is switched to 2P+2P to further reduce the speed. By reducing the speed (rotation speed) in stages in this way, it is possible to prevent a sudden load from being placed on the motor 10.

[0071] When the vehicle speed drops to about 30 km / h (700 rpm) on a gentle downhill slope, the connection configuration of motor 10 is switched to 1 parallel (series, i.e., 4S) and the vehicle reaches a flat road. On downhill slopes, the power supply can be recharged by applying regenerative braking as described above.

[0072] The above process is shown in Figures 10 and 11 as switching between high speed (Top: T), medium speed (Second: S), and low speed (L), and will be explained below. First, the vehicle starts on flat ground and travels in L mode when the speed is in the range of 0-20 km / h. At 20 km / h, it switches to S mode, and at 60 km / h, it switches to T mode, which can reach up to 100 km / h. In section A shown in Figure 10, the accelerator is fully open, and the coil connection is automatically switched by the coil connection pattern switching device 80 after detecting the rotation speed of the motor 10.

[0073] In this section, as the vehicle accelerates, the rotational speed of motor 10 increases, while the accelerator signal input by the driver (manual accelerator signal) outputs a signal to increase the rotational speed to the maximum. As a result, the manual accelerator signal becomes greater than the rotational speed of motor 10.

[0074] Next, as 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, maintaining the S state even when entering a steeper slope. In this section (section B' in Figure 10), the coil connection pattern switching device 80 is controlled not by the motor's rotational speed (velocity), but by the accelerator opening (current control). When the vehicle reaches the top of the slope and enters flat ground (exits section B'), it switches to rotational speed control (velocity control), and the coil connection pattern switching device 80 according to the present invention switches to L to accelerate the vehicle, switches to S as the speed (rotational speed) increases, and then switches to T. At this point, the top speed in T reaches about 100 km / h.

[0075] In section B shown in Figure 10, the switching control of the coil connection pattern switching device 80 (see Figure 1) based on the accelerator opening takes priority. Therefore, if the rotational speed (velocity) of the motor 10 is lower than the support based on the accelerator opening, the coil connection pattern switching device 80 will be switched by the current instruction based on the accelerator opening. In other words, in section B', the rotational speed of the motor 10 decreases as the vehicle speed decreases, but the function of the coil connection pattern switching device 80 is automatically switched by the current value in order to maintain the vehicle speed at 60 km / h.

[0076] As described above, in section B, the rotational speed (velocity) of motor 10 remains low relative to the accelerator opening. Therefore, in section B as well, the manual accelerator signal becomes greater than the rotational speed of motor 10.

[0077] Next, when moving from a flat road to a downhill slope, even on a steep downhill, the system initially starts in state T, switches to state S once the slope becomes gentler, and then switches to state L upon reaching flat ground. In this section C, due to gravity acceleration, the rotational speed (velocity) of motor 10 becomes greater than the accelerator opening (current command). Therefore, the coil switching device switches according to the driver's adjustment of the accelerator opening (accelerator instruction). This switching of the accelerator opening is handled by the switching of the coil pattern of the present invention.

[0078] Next, Figure 11 illustrates another mode of the driving switching pattern. In the example shown in Figure 11, the top gear is selected in the range from flat ground to a small incline. Then, when the incline becomes a medium angle, it switches to the second gear, and when the incline becomes large, it switches to the low gear. When the incline becomes gentler at the top of the slope, it switches back to the second gear, and when it reaches a plateau and becomes flat, it switches to the top gear. In this way, the coil connection pattern switching device 80 has the gear switching function of a conventional automobile. In other words, this gear switching (8-stage switching) is handled by the coil pattern connection switching.

[0079] Generally, there is a trade-off between increasing the torque of a motor and increasing its maximum rotational speed. Increasing the torque of a motor lowers the maximum rotational speed, and increasing the maximum rotational speed lowers the maximum torque. Conventionally, attempts have been made to increase rotational speed by increasing the voltage of the power supply and increase torque by increasing the current of the power supply. However, these control methods have safety issues and technical limitations. The inventors have therefore solved this conventional problem by considering an electrically automatic switching method for motors with different characteristics. By employing such a method, it is possible to achieve the same effect as automatically switching between multiple motors with different characteristics by enabling multiple stages of circuit switching (switching of coil connections by a coil switching device), such as Low gear, 2nd gear, and Top gear, while using only one motor.

[0080] Here, the Low gear offers high torque and low rotational speed, allowing high torque to be generated with a small current. Increasing rotational speed in the Low gear requires high voltage, but since the Low gear operates at low rotational speeds, high voltage is not necessary. The 2nd gear offers medium torque and medium rotational speed, while the Top gear offers low torque and high rotational speed (high rotation is possible with low voltage). Obtaining high torque in the Top gear requires a large current, but since the Top gear operates at low torque, a large current is not necessary.

[0081] By adding a coil connection switching function to the motor in this way, a single motor can handle various driving scenarios. Consequently, high voltage and high current output of the driver become unnecessary, reducing motor overload and suppressing rapid temperature increases. This contributes to power saving.

[0082] As described above, the motor 10 according to the present invention enables switching between a series Low state and multiple parallel or mixed series-parallel coil configurations by selecting the position and number of coils for each phase, thereby enabling three or more characteristic switching stages, such as second and third. For this reason, when applied to electric vehicles such as bicycles, motorcycles, so-called mobility scooters, wheelchairs, and automobiles, it becomes possible to switch between multiple gear stages (coil connection switching) without the need for mechanical gears.

[0083] When the motor 10 according to the present invention is applied to the propulsion power of an electric vehicle, the vehicle speed of the electric vehicle to be applied is detected by an encoder or resolver, and the coil switching is applied based on the detected vehicle speed value. Vehicle speed detection may be performed using sensors not shown, and various conventional (known) methods can be used. The timing of the coil switching is performed by an automatic coil switching device 80 that has been set to switch timing based on various speed detections, but the timing of this automatic switching will be described in a separate section.

[0084] [Example of connecting multiple coils] Figure 12 shows variations in coil connections for a 5-coil system (where each phase has 5 coils; the same applies hereafter). Note that the switching circuit is omitted from the drawing. Also, for the sake of clarity, each coil is assumed to be 1Ω. As shown in the figure, if 5 coils are available, 1Ω, 2Ω, 3Ω, 4Ω, and 5Ω can be selected by choosing the number of coils to use. Furthermore, by switching the series-parallel combination of the coils, 0.2Ω (all coils in parallel), 0.83Ω (a group of 3 coils in parallel and a group of 2 coils in parallel connected in series), 1.25Ω (a group of 4 coils in parallel with one coil in series), 2Ω (two groups of 2 coils in parallel connected in series, with one more coil in series), 2.33Ω (a group of 3 coils in parallel and a group of 2 coils in series connected in series), and 3.5Ω (two coils in parallel with a series coil of 3 coils connected in series) can also be selected. Increasing the number of coils allows for even finer pattern selection. Note that if all are connected in series, the resistance will be 5Ω.

[0085] Next, the method of switching coil connections in the case using these 5 coils will be explained using the image diagram in Figure 13. In the diagram, Lu, Lv, and Lw are coils, and the numbers next to them indicate the coil numbers. For the switches, Svx, Svx2, Svx3, and Svx4 (x means U, V, and W, and the same applies below) are V switches, Stx1, Stx2, Stx3, and Stx4 are Through switches, and Scx1, Scx2, Scx3, and Scx4 are COM switches. When the number of coils in each phase increases, each coil and each switch increases in the same pattern vertically in this circuit diagram.

[0086] With 5 coils per phase, there are a total of 18 effective coil combinations. The number of switches required is (=9 × ((number of coils / phase) - 1) = 36), so smoother switching can be expected simply by changing the ON / OFF combination of the switches. Tables 1 and 2 show the variations in coil switching and connection patterns for a 5-coil / phase motor. Table 1 shows the cases where (1) the coils are sorted in order of number used, and Table 2 shows the cases where (2) the coils are sorted in order of torque constant and rated torque. [Table 1] When sorted by the number of coils used [Table 2] When arranged in the order of torque constant and rated torque

[0087] Regarding the approach to coil connection patterns, firstly, (a) we exclude those that generate circulating current due to different generated voltages. That is, connection patterns that generate circulating current, such as when coil sets with different induced voltages are connected in parallel, are excluded. Next, (b) in the case of connections where the torque constant and inter-terminal resistance / inductance are the same, for example, we can consider two sets of two coils connected in series and then connecting those two sets in parallel, or two sets of two coils connected in parallel and then connecting those two sets in series. We have adopted the latter connection method. The former connection is expected to reduce circulating current caused by variations in coil characteristics, but achieving this would require increasing the number of switches, so in this example we have adopted the latter.

[0088] There are a total of 18 effective coil connection patterns that prevent circulating current, but the torque constants are limited to only 5. First, (1) by selecting the connection with the largest rated torque and switching in the order No.1→No.2→No.4→No.6→No.7, it is possible to achieve both "smooth switching" and "minimum losses (copper losses)". Next, (2) by switching in the order No.1→No.8→No.13→No.16→No.18 so that the difference between R and L between terminals during switching becomes small, the fluctuation of the motor current during switching becomes smaller, and further reduction of shock during switching can be expected (in this case, increased losses at high rotational speeds are sacrificed). In other words, the 5 coil connection patterns are proposed to consider not only "minimizing copper losses" but also "smooth switching". For example, when switching from a torque constant of 4kt to 3kt, directly switching from (3S+2P) to (1S+2P+2P) reduces the terminal resistance from 3.5Ω to approximately 2.0Ω, resulting in a jump in motor current that doubles. However, by adding three intermediate connection patterns, such as (3S+2P)→(3S)→(2S+2P)→(2S+3P)→(1S+2P+2P), the terminal resistance gradually decreases from 3.5Ω→3.0Ω→2.5Ω→2.33Ω→2.0Ω, thus reducing the jump in motor current value and mitigating the shock associated with the switch. Although the number of switches increases by three, if the switch is performed every 0.1 seconds, for example, the time required for switching only increases by 0.3 seconds. Then, by switching in the order (3) No.1 → (No.8 →) No.2 → (No.13 → No.9 → No.3 →) No.4 → (No.16 → No.14 → No.10 → No.5 → No.11 →) No.6 → (No.18 → No.17 → No.15 → No.12 →) No.7, the shock during switching is minimized, and copper loss after switching can also be minimized.

[0089] As described above, by using not only simple series-parallel switching patterns but also mixed series-parallel configurations, it becomes possible to achieve smoother switching with less switching shock. It is recommended to effectively use all 5 coils. Furthermore, if it is possible to anticipate patterns with different resistance values ​​for the same number of coils and the same voltage, the pattern with the lower resistance value should be adopted. It is also possible to simplify switching control by reducing the number of switching patterns even with the same number of coils (for example, when using all 5 coils, you can omit 5S (all in series) and 3P+2P (connecting 3 coils in parallel and 2 coils in parallel in series). Also, as will be explained later (Figure 42), the rotation speed of all parallel (5P) is significantly (twice as much) compared to the next position and below, so it is better not to use this as well. As a variation of the 5 coil configuration, if one coil (supplementary coil) is connected in parallel to one coil section of the series section as shown in Figure 43, the resistance of that section can be shared with the additional coil, and heat generation can be suppressed. The configuration shown in Figure 43 will be explained in detail later.

[0090] Figure 14 shows connection variations for 4 coils (where each phase has 4 coils; the same applies hereafter), similar to Figure 12, and Figure 15 shows connection variations for 3 coils (where each phase has 3 coils; the same applies hereafter). The dashed arrows in Figure 14 indicate the switching flow as the resistance value changes. Both Figure 14 and Figure 15 allow for the selection of mixed series and parallel patterns, similar to Figure 12, and can also be used with an odd number of coils, as shown in Figures 12 and 15.

[0091] Similarly, the case of 6 coils (where there are 6 coils in each phase; the same applies hereafter) is shown in Figure 16. In the case of 6 coils, the desirable circuit selection pattern is the wiring method that minimizes the resistance value when the number of coils used is the same. And for the same desired back electromotive force, a lower resistance has an energy saving effect (extends battery life). Therefore, in the example patterns above, if the back electromotive force generated by one coil is 1V, it is recommended to select (1) for 1V, (5) for 2V, (8) for 3V, (9) for 4V, (10) for 5V, and (12) for 6V.

[0092] Similarly, Figures 17 and 18 show patterns for 8 coils (when there are 8 coils in each phase; the same applies hereafter). The total number of coils in each phase will be divided according to the number of switching stages (series (=1 parallel), multiple parallel patterns), but it is desirable to divide them evenly to prevent the generation of circulating current between coils. For example, if the total number of coils is 24, then in series (1 parallel), 24 coils will be connected in series, and in 2 parallel, 12 sets of 2P will be connected. Similarly, in the case of 3 parallel, 8 sets of 3P will be connected, in the case of 4 parallel, 6 sets of 4P will be connected, and in the case of 6 parallel, 4 sets of 6P will be connected, thus dividing them evenly. Further increasing the number of divisions, 3 sets of 8P and 2 sets of 12P will be connected, and in the case of 24 parallel, one coil will be divided into each and all 24 coils will be connected in parallel. By dividing the coils evenly in this way, there will be no difference in the number of coils in parallel in each phase, thus suppressing the generation of circulating current. Therefore, it is possible to suppress the heat generation due to the generation of circulating current and avoid an increase in energy (power) waste (loss).

[0093] [Effects of the present invention other than power saving] This invention makes it possible to achieve both high rotational speed and high output torque. The maximum rotational speed N under no load is given by, where kt is the motor's torque constant and Vb is the power supply voltage.

number

[0094] On the other hand, the motor shaft output torque T is given by, if the motor current is Im,

number

[0095] Generally, the power supply voltage Vb is limited to a maximum voltage by the battery voltage or boost circuit, and the motor current Im is limited to a maximum current value by the motor driver circuit. In situations where the rotational speed is limited by the power supply voltage and the maximum torque is limited by the maximum current value of the motor driver circuit, if it is necessary to further increase the maximum rotational speed or the maximum output torque, the configuration of the present invention can be used to achieve higher rotational speed and higher output torque without changing the power supply voltage or the motor driver circuit.

[0096] In other words, when high-speed rotation is required, the motor's torque constant kt can be reduced by connecting the coils in parallel using a switching circuit, thereby increasing the maximum rotational speed. Conversely, when high torque is required, the motor's torque constant kt can be increased by connecting the coils in series using a switching circuit, thereby increasing the output torque T even under the same motor current Im.

[0097] [Circuit Configuration] The circuit used in the embodiment of the present invention will be explained with reference to Figures 19 to 24. Figure 19 shows the overall circuit configuration. 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 controller 31 inputs it to the shift register 32 as a command signal Sin(serial input).

[0098] First, let's briefly explain the general operation using Figures 19 and 20. When the command signal Sin is input, the shift register 32 outputs the command signal from terminals Q0, Q1, and Q2, respectively. At this time, the shift register 32 adjusts the output from each terminal (Q0, Q1, Q2) to create a shift due to the action of the clock signal clk. Specifically, when Sin is L (Lo, the same applies below) and clk rises, Q0 becomes L, and when Sin is H (Hi, the same applies below) 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 signal of Q0. Specifically, when Q0 is L and clk rises, Q1 becomes L, and when Q0 is H and clk rises, Q1 becomes H. If there is no change in the signal of Q0, the previous state, i.e., L or H, is maintained. Q2 changes based on the signal of Q1. Specifically, when Q1 is low and clk rises, Q2 becomes low, and when Q1 is high and clk rises, Q2 becomes high. If there is no change in the signal of Q1, it remains in the same state as Q1, i.e., low or high.

[0099] The outputs from Q0 and Q2 are input to the NOR element 33, and a command signal is output as EN (XNOR: Exclusive Noah). The NOR element 33 allows the output of the command signal when the signals from Q0 and Q2 match, and does not allow the output of the command signal when the signals do not match. Specifically, if the command signal output from Q0 is L and the output from Q2 is also L, the gate becomes H and the output of the command signal is allowed. Similarly, if the output from Q0 is H and the output from Q2 is H, the gate becomes H and the output of the command signal is allowed. On the other hand, if the command signal output from Q0 is L and the output from Q2 is H, or if the output from Q0 is H and the output from Q2 is L, the gate becomes L and the output of the command signal is not allowed.

[0100] The command signal output from Q1 in the shift register 32 is input to the AND element 35 via the NOT element 34, and also directly to the AND element 36. Since the output signal from the NOT element 34 is the inverse of the input signal (if the command signal output from Q1 is L, the output from the NOT element 34 is H; if the command signal from Q1 is H, the output from the NOT element 34 is L), the AND element 35 and the AND element 36 each receive the opposite command signal as the command signal from Q1.

[0101] AND elements 35 and 36 will output a high (H) command signal only when the command signal from Q1 and the output signal from NOR element 33 are both high (H). As mentioned above, AND elements 35 and 36 receive opposite signals (L or H) as command signals from Q1, so they will never output a high (H) command signal simultaneously. Furthermore, there is a timing difference in the switching timing of the command signals from Q0, Q1, and Q2 in the shift register 32, so the switching timing of the output signal from NOR element 33 and the switching timing of the command signal from Q1 will never coincide. For this reason, there is no risk that the switching timing of the command signals between AND elements 35 and 36 will also coincide.

[0102] The outputs from AND elements 35 and 36 are input to blocks 37, 38, and 39, respectively, 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 AND element 35 is input, is the input terminal for the gate serial (series side) switching signal, and G1p, to which the command signal output from AND element 36 is input, is the input terminal for the gate parallel (parallel side) switching signal. As described above, the command signals from AND elements 35 and 36 never coincide, resulting in a difference in the L and H switching timings. Therefore, as shown in Figure 20, there is no timing when G1s and G1p are simultaneously ON (Hi), and a short circuit does not occur. The numbers "1" in G1s and G1p indicate the circuit section numbers, and using Table 15 (described later in a separate section) as an example, the terminals in Kx11 in the circuit section can be represented as G11s and G11p, respectively.

[0103] Figure 21 shows an example of a circuit diagram that constitutes a block. Although the example shown in Figure 21 is an example of a circuit diagram for a block that constitutes the U phase, the blocks that constitute the V phase and W phase have a similar configuration. For example, Lu1h becomes Lv1h in the V phase and Lw1h in the W phase, and Lu2h becomes Lv2h and Lw2h. Also, Lu1l becomes Lv1l and Lw1l, and Vu becomes Vv and Vw, respectively. In the example shown in Figure 21, the switching element and FET (field-effect transistor) element 40 corresponding to the circuit part are shown, but when using a switching element in carrying out the present invention, it is not limited to using an FET element.

[0104] Figure 22 shows details of the control unit that generates dead time and outputs command signals in Figure 19, and details of the area within the frame including reference numerals 32-36 in Figure 19. Figure 23 shows the FET switching circuit, and details of the U-phase block reference numeral 37 in Figure 19, but the V-phase block reference numeral 38 and the W-phase block reference numeral 39 are similar.

[0105] Figure 24 shows an example of the overall circuitry for coil switching (i.e., motor switching) operation when the coreless motor with automatic switching device of this embodiment is applied to an electric motorcycle. Reference numeral 100 denotes the speed control part of the switching operation unit, reference numeral 110 denotes the emergency stop switch, reference numeral 120 denotes the mode selection switch (Auto / Manual) for automatic or manual coil switching, reference numeral 130 denotes the changeover switch when manual selection is made with reference numeral 120 (selection of 4P (4 parallel), 2P+2P (2 parallel), 4S (1 parallel)), and reference numeral 140 denotes the electronic circuit of the coil switching device. Each of these blocks will be connected to the motor controller (motor driver) via J1 (DB25_Male) as shown in the figure.

[0106] [Verification data] The following data shows the power-saving effect of the overall system incorporating the coil switching device according to the present invention. The measurement environment is as follows: The motor used is a CPH110 from Coreless Motor Co., Ltd. (Litz wire is applied to the coil of a Coreless Motor Co., Ltd. coreless motor. Rated specifications are as shown in Table 3), the driver is a RoboteQ HIOKI PW3336 from Unipulse Co., Ltd., the torque and tachometer are Unipulse Co., Ltd. TM-301, measured with UTM2-20Nm, the PS (main power supply) is a KNX6060D from THAOXIN, the drive voltage is 48V (operating voltage CPHC110: DC48V, BXR-06-10-005: DC24V), and the motor rotates clockwise when the shaft is facing the user. Circuit information is as shown in Figure 25. [Table 3]

[0107] Note that for Tables 4-13, those marked (B) are generally under the same conditions (wire length 2720mm), however, the conditions for (A) in Tables 11 and 13 are similar to (B) in the other tables, but the motor used is a 1kW single unit, the cable inside the driver motor (wire length 1200mm), the circuit is a mechanical contact type relay, the power supply is 48V using two batteries, and Litz wire is used for the motor coil. As can be seen in the table below, power saving effects were obtained in all cases. [Table 4] 15rpm current (B) [Table 5] 25rpm current (B) [Table 6] 50rpm current (B) [Table 7] 100rpm current (B) [Table 8] 200rpm current (B) [Table 9] 550rpm current (B) [Table 10] 940rpm current (B) [Table 11] 2000rpm current (A) [Table 12] 2500rpm current (B) [Table 13] 3000rpm current (A)

[0108] Table 14 summarizes the data obtained by changing the wire distance between the driver and the coil selection device at 50 rpm and examining the effect of the choke coil. In the table, "Reduction Degree" refers to the degree of reduction in battery current (%). [Table 14]

[0109] Figure 26 shows the measurement results of battery current consumption based on cable length for 4-parallel (4 coils in parallel) and 1-parallel (4 coils in series) configurations. Switching from 4-parallel to 1-parallel reduces motor current to 1 / 4, and also reduces losses due to the cables. The longer and thinner the wiring cable, the greater the battery current reduction effect of the coil switching device. In reality, when running cables to connect the motor and battery in an electric vehicle, a distance of 1 meter or more is essential, so the power saving effect is enormous.

[0110] [Example of stator coil configuration 1] In the motor 10 shown in Figure 2, as shown in Figure 27, each phase constituting the stator coil body 18 is composed of two coils (first coil U1, second coil U2, first coil V1, second coil V2, first coil W1, second coil W2). The stator coil body 18 according to this embodiment is composed of three phase coils. Note that this is an example, and the configuration of the coils does not determine the number of poles. For example, in the case of 12 poles, each of the phases U1, U2, V1, V2, W1, and W2 may be a coil body with 6 coils in series, or in the case of 8 poles, each of the phases U1, U2, V1, V2, W1, and W2 may be a coil body with 4 coils in series. Thus, the number of poles cannot be determined from the configuration of the stator coil body 18, and any number of poles is acceptable as long as the number of poles is even. Between the coils that make up each phase (first coil U1 and second coil U2, first coil V1 and second coil V2, first coil W1 and second coil W2), there is a circuit section 20 (20U, 20V, 20W) that constitutes a changeover switch.

[0111] The circuit section 20 consists of two switches (first switch A and second switch B) arranged in parallel, each with one input port and two output ports. The first coils U1, V1, and W1 are connected to the input port of the first switch A, and the first bypass wire is connected to the input port of the second switch B. On the output port of the first switch A, the second coils U2, V2, and W2 are connected to port a, and the second bypass wire is connected to port b. On the output port of the second switch B, port a is open (unconnected), and branch wires from the second coils U2, V2, and W2 are connected to port b.

[0112] This circuit configuration allows the first coils U1, V1, W1 and the second coils U2, V2, W2 to be connected in series or in parallel by switching the switches that make up the circuit section 20. Specifically, when both the first switch A and the second switch B are connected to port a, the first coils U1, V1, W1 and the second coils U2, V2, W2 are connected in series (see the solid lines 20U, 20V, 20W in Figure 27). On the other hand, when both the first switch A and the second switch B are connected to port b, the first coils U1, V1, W1 and the second coils U2, V2, W2 are connected in parallel (see the dashed lines 20U, 20V, 20W in Figure 27). In other words, the switching timing of the first switch A and the second switch B is configured to coincide.

[0113] In this type of switching control, the system in which the first coil U1, V1, W1 and the second coil U2, V2, W2 are connected in series (referred to as the first system) exhibits good torque characteristics. On the other hand, the system in which the first coil U1, V1, W1 and the second coil U2, V2, W2 are connected in parallel (referred to as the second system) exhibits good rotational characteristics. To explain this using the motor's torque constant, connecting them in series increases the motor's torque constant, resulting in a larger torque per unit current (good torque characteristics). Conversely, connecting them in parallel decreases the motor's torque constant, making it possible to rotate them at high speeds (good rotational characteristics). In this embodiment, the purpose of terminal switching is to change the torque constant, and as a result, the rotational characteristics and torque characteristics change, allowing for the provision of an optimal motor for each situation.

[0114] Figure 28 shows the torque-to-rotational speed relationship characteristics (TN characteristics) and the torque-to-current relationship characteristics (TI characteristics) for the first and second systems, respectively. Comparing the second and first systems, it can be seen that the second system has a higher operating speed range, resulting in a steeper rise in power consumption as torque increases. On the other hand, while the first system can generate high torque at low rotational speeds, its maximum rotational speed is only about half that of the second system.

[0115] Based on the characteristics of each system, it is considered that the advantages of each motor can be effectively utilized by using the first system in the low rotation range and the second system in the high rotation range. Figure 29 shows the motor characteristics (TN characteristics and TI characteristics) obtained when switching between the first system and the second system in the rotation range where the maximum torque is 1 / 2. In the motor 10 of this embodiment, which switches between systems, high torque can be generated while suppressing power consumption (current) in the low rotation range. Furthermore, in parts where operation at low torque is not a problem, it becomes possible to achieve higher rotation speeds that cannot be obtained with the first system.

[0116] To realize such a configuration, the switches (first switch A, second switch B) constituting the circuit section 20 must be switched simultaneously in three phases: U-phase, V-phase, and W-phase. For this reason, the motor 10 according to the embodiment is equipped with a control unit 22 that outputs switching signals to the circuit section 20. The control unit 22 is configured to use a predetermined rotational speed as a reference, increasing the number of coils connected in series in each phase at lower rotational speeds, and increasing the number of coils connected in parallel at higher rotational speeds. This allows for a balance between power consumption and generated torque, and also broadens the usable rotational range.

[0117] When a motor 10 with this configuration is applied to the vehicle's power supply to form an electric vehicle, the output characteristics of the first system (series) and the second system (parallel) will show the trends shown in Figure 30. Therefore, the system can be switched between three zones, taking into account the generated torque, the required rotational speed range, and power consumption.

[0118] In other words, Zone 1 is best applied when output torque is needed (generally more than half of the maximum torque), such as when starting or climbing hills (System 1: Low RPM). Zone 2 is best applied when the RPM is relatively low, output torque is not needed (generally less than half of the maximum torque), and power consumption should be kept down (for example, during normal driving) (System 1: High RPM). Furthermore, Zone 3 is best applied when high RPM is needed and output torque is not needed, such as during high-speed driving (generally less than half of the maximum torque) (System 2: High RPM).

[0119] Coreless motors lack an iron core. Consequently, their inductance is small. However, a large inductance makes it difficult for current changes to occur. Therefore, forcibly generating a change in current will produce a high voltage. If a large current is flowing and the current is suddenly cut off (for example, if switching from parallel to series, the current is cut off at that moment), a high voltage will be generated. This can cause an overvoltage in the circuit, greatly increasing the likelihood of damaging the circuit's components. This is because circuit components are vulnerable to overvoltage.

[0120] Core motors, in which coils are wound around an iron core, have high inductance. Therefore, countermeasures must be taken to prevent the generation of large voltages during circuit switching, and additional procedures such as temporarily cutting and switching the current must be implemented during operation. Consequently, when using winding switching in core motors with coils wound around an iron core, it becomes necessary to use multiple elements for various preventative measures to avoid accidents caused by overvoltage due to sudden current changes during winding switching, resulting in a complex circuit configuration.

[0121] In contrast, the motor 10 (coreless motor) configured according to this embodiment generates only a fraction of the overvoltage of a cored motor (iron core motor) (for example, less than 1 / 20). Therefore, extra auxiliary equipment and accident avoidance work are unnecessary, and series and parallel switching can be performed instantaneously. This is a technology that was first conceived and demonstrated by the inventors of this application. However, the effects of this embodiment demonstrate effects unique to coreless motors, and since cored motors also have similar effects from the viewpoint of power saving, the present invention is not limited to coreless motors. Furthermore, among cored motors, the slotless type has a smaller inductance compared to a normal cored motor because it does not have iron core teeth, making it a suitable example similar to a coreless motor.

[0122] Generally, when motors are applied to vehicles, in the case of cored motors with high inductance, if the current supplied to the motor is cut off while a load is applied, a resistance acts to stop the rotation of the rotor, causing a decrease in speed and resulting in a shock. In contrast, when the coreless motor 10 according to this embodiment is used, it can be said that shocks caused by inductance are less likely to occur.

[0123] [Example of stator coil configuration 2] Next, with reference to Figure 31, the configuration of the motor 10 according to the second embodiment will be described. The motor 10 according to this embodiment has a different configuration of the stator coil body 18 compared to the motor 10 according to the first embodiment.

[0124] The stator coil body 18 according to this embodiment is a 3-phase 12-pole system using four coils (12 in total) for each phase. In a stator coil body 18 with this configuration, circuit sections 20 (20U1, 20U2, 20U3, 20V1, 20V2, 20V3, 20W1, 20W2, 20W3) are provided between each of the coils constituting each phase (first coil U1, second coil U2, third coil U3, fourth coil U4, first coil V1, second coil V2, third coil V3, fourth coil V4, first coil W1, second coil W2, third coil W3, fourth coil W4).

[0125] The configuration of circuit section 20 is the same as that of circuit sections 20U1, 20U3, 20V1, 20V3, 20W1, and 20W3 in the first embodiment. On the other hand, for circuit sections 20U2, 20V2, and 20W2, the second switch B is configured such that the number of input ports and the number of output ports are reversed compared to the first switch A.

[0126] In a motor 10 with this configuration, 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 U1 to the fourth coil U4, the first coil V1 to the fourth coil V4, and the first coil W1 to the fourth coil W4 are connected in series (this state is called 1 parallel: see Figure 31. Select the solid line for each circuit section).

[0127] Furthermore, if the first switch A and second switch B of circuit sections 20U2, 20V2, and 20W2 are set to port b from the 1-parallel configuration, for example, in the U phase, the first coil U1 and the second coil U2 are connected in series, and the third coil U3 and the fourth coil U4 are connected in series, while the pairs of the first coil U1 and the second coil U2, and the pairs of the third coil U3 and the fourth coil U4 are connected in parallel. Note that the coils are connected similarly in the V and W phases as well (this state is called 2-parallel: see Figure 31. 20U2, 20V2, and 20W2 are selected by dashed lines, and other selected circuits are selected by solid lines).

[0128] Furthermore, in each of the U, V, and W phases, if the first switch A and the second switch B are set to port b for circuit sections 20U1 to 20W3, then the first coils U1 to U4, the first coils V1 to V4, and the first coils W1 to W4 will be connected in parallel (this state is called 4-parallel: see Figure 31. All selected circuit sections are set to the dashed line side).

[0129] In the motor 10 configured as described above, the torque characteristics are higher for systems with more coils connected in series (1 parallel as described above), and the rotational characteristics are higher for systems with more coils connected in parallel (4 parallel as described above). Taking advantage of these characteristics, Figure 32 shows the relationship characteristics between torque and rotational speed (TN characteristics) and the relationship characteristics between torque and current (TI) when the motor 10 is operated by switching between 1-parallel to 4-parallel systems.

[0130] As shown in Figure 32, by switching the system between 1-parallel, 2-parallel, and 4-parallel configurations as the rotational 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 rotational speed range that cannot be achieved with 1-parallel configuration. For example, when a motor 10 with such a configuration is applied to the propulsion power of an electric vehicle, the 4-parallel, 2-parallel, and 1-parallel (i.e., all coils in series) configurations function as a gear shift mechanism corresponding to top gear, second gear, and low gear, respectively. Even with a motor 10 with such a configuration, a predetermined torque can be obtained even in the high rotational speed range, similar to the motor 10 according to the first embodiment.

[0131] Furthermore, in this example as well, by applying it to a coreless motor, the self-inductance can be kept low, and the responsiveness from switching by connection switching by the circuit section 20 to characteristic switching can be improved. In addition, by increasing the number of coils and circuit sections, the degree of freedom in switching characteristics can be improved.

[0132] [Other stator coil configuration examples] The present invention is not limited to a configuration in which a circuit unit is provided in a single coil unit, and the number of coils placed between circuit units is not limited to one. For example, by varying the number of coils placed between circuit units and devising the arrangement of the circuit units, it becomes possible to equally distribute the number of coils connected in series when coils are connected in parallel, thereby broadening the range of characteristic changes due to the combination of coils connected in series and coils connected in parallel.

[0133] For example, in a motor 10 equipped with a stator coil body 18 with the configuration shown in Figure 33, 12 coils (1st coil to 12th coil: U1-W12) are arranged in each phase (U phase, V phase, W phase), and five circuit sections (20U1-20W5) are provided. As an example, in the U phase, the circuit sections 20U1-20U5 are provided between coil U3 and coil U4, between coil U4 and coil U5, between coil U6 and coil U7, between coil U8 and coil U9, and between coil U9 and coil U10, respectively. The arrangement of the circuit sections (20V1-20W5) is the same for the V phase and W phase.

[0134] Each circuit unit (20U1-20W5) is equipped with ports a1, b1, a2, b2, c1, and c2, respectively. In the circuit units (20U1-20W5) having such ports, ports a1 and b1 are switchable between port c1, and ports a2 and b2 are switchable between port c2, and both are configured to switch simultaneously.

[0135] Next, the relationship between the switching of the connection configuration of the stator coil body 18 and the switching of the circuit sections (20U1-20W5) in this embodiment will be explained. Note that the corresponding circuit sections (20U1-20W5) in each phase are switched simultaneously, so in the following explanation, circuit sections 20U1, 20V1, and 20W1 will be referred to as circuit section 20X1, circuit sections 20U2, 20V2, and 20W2 as circuit section 20X2, circuit sections 20U3, 20V3, and 20W3 as circuit section 20X3, circuit sections 20U4, 20V4, and 20W4 as circuit section 20X4, and circuit sections 20U5, 20V5, and 20W5 as circuit section 20X5.

[0136] In this embodiment of the motor, when connected in series (one parallel), the switching is set so that ports a and c are connected in all circuit sections 20X1-20X5. When connected in series (two parallel), only circuit section 20X3 is switched so that ports b1 and c are connected. When connected in series (three parallel), circuit sections 20X2 and 20X4 are switched so that ports b and c are connected. Furthermore, when connected in series (four parallel), circuit sections 20X1, 20X3, and 20X5 are switched so that ports b and c are connected.

[0137] When the coils constituting each phase are arranged in a cylindrical shape, the configuration shown in Figure 34 is obtained. In the example shown in Figure 34, the boundary between coil U1 and coil U12 is used as the power input / output terminal, and coils U1-U12 are arranged clockwise in a cylindrical (ring-shaped) configuration. In this coil configuration, when the above 2 parallel connections are implemented, the coils are divided (into two equal parts) at circuit section 20U3, and coils U1-U6 and U7-U12 are connected in series. Furthermore, when the above 3 parallel connections are implemented, the coils are divided (into three equal parts) at circuit sections 20U2 and 20U4, and coils U1-U4, U5-U8, and U9-U12 are connected in series. In addition, when the above 4 parallel connections are implemented, the coils are divided (into four equal parts) at circuit sections 20U1, 20U3, and 20U5, and coils U1-U3, U4-U6, U7-U9, and U10-U12 are connected in series. Note that while Figure 34 shows the coil arrangement for the U phase, the arrangement is similar for the V phase and W phase.

[0138] Figure 35 also shows an example of a 6-stage switching circuit using the present invention. In this example, three phases U, V, and W are used, and 12 coils are used for each phase, allowing for 6-stage switching by changing the coil connection method to 1 parallel (i.e., all in series), 2 parallel, 3 parallel, 4 parallel, 6 parallel, and 12 parallel (2 or more in parallel). In the example shown in Figure 35, the explanation is given using a combination of relays as shown in the figure for simplicity of explanation, but as mentioned above, the circuit device may be consolidated using one or more switching elements (semiconductor elements) such as FETs. This is because consolidating the circuit device using semiconductor elements makes it possible to make the motor 10 itself smaller and lighter, and to simplify the internal wiring. In the diagram, a1, a2, b1, b2, c1, and c2 represent ports (contacts), Lu1 to Lu12, Lv1 to Lv12, and Lw1 to Lw12 represent coils, and Ku1 to Ku11, Kv1 to Kv11, and Kw1 to Kw11 represent circuit sections (relays).

[0139] In the circuit section, ports c1 and c2 switch simultaneously. When port c1 is connected to port a1, port c2 is simultaneously connected to port a2. In this connection configuration, the coils on both sides of the circuit section are connected in series. Note that port a2 is an unused terminal (unconnected) in the circuit section. On the other hand, when port c1 is connected to port b1, port c2 is simultaneously connected to port b2. In this connection configuration, the coils on both sides of the circuit section are connected in parallel. If there are 11 such circuit sections, depending on whether the selected destination for each circuit section is a or b, it is possible to select 1 parallel (1 parallel is in series), 2 parallel, 3 parallel, 4 parallel, 6 parallel, or 12 parallel connections, as shown in Table 15. Note that in the table, x in Kx1 to Kx11 represents u, v, and w (for example, Kx1 for the U phase becomes Ku1). [Table 15]

[0140] [Automatic switching timing] Multiple phases are required to rotate the motor, but the method of switching each phase is the same. Although the switching operation is automatic, manual operation may also be used, and the essence of this embodiment is that multiple stages of switching are possible in addition to series switching. The switching operation involves selecting the number of stages using the gear switching operation means 30 in Figure 19, sending the selection instruction to the controller 31, and the controller 31 sending the operation signal Sin to the shift register 32. Figure 19 shows the coil automatic switching device 80 as a whole. The gear switching operation means 30 is contained within the coil automatic switching device 80. An example of the switching timing is explained in Figure 36.

[0141] Figure 36 illustrates a method of using motor voltage as the switching timing for the automatic coil switching device 80. Basically, the switching is performed so that the TN / TI characteristics fall within the regions shown in this figure. In this example, each of the three phases has four coils, and for simplicity, it is shown in Figure 14 with 4 parallel (4P), 2 parallel (2P+2P), and 1 parallel (4S) configurations. Of course, other parallel + series combinations are also acceptable. The motor voltage is shown as a percentage of the maximum applied voltage (100%). Examples of switching conditions are shown in Table 16. Switching the connections according to the conditions in Table 16 will result in each region in Figure 36. The gear switching operation means 30 in Figure 19 may have such a function, or the gear switching operation means 30 may be a means for manually switching gears, while the controller 31 has a function to monitor the motor voltage and current and automatically switch according to the conditions in Table 16. [Table 16]

[0142] In this way, the motor voltage and motor current are measured by measuring devices (not shown) connected to the motor, and the data is stored in a semiconductor element within the automatic coil switching device 80 so that it can be switched automatically.

[0143] Here, it is important to consider the maximum driver current. Unlike fixed power sources in buildings, the power supply for mobile devices cannot supply unlimited current. Power supplies (batteries) have internal resistance, and if a large amount of current flows through the motor driver, not only will there be significant losses, but even a momentary surge in current exceeding the limited current limit can cause damage. Therefore, it is important to consider the maximum current (more preferably the absolute maximum rating) of the driver.

[0144] To explain from the perspective of the motor's TI and TN characteristics, the TN·TI characteristic diagrams for three types of motors with different maximum rotational speeds (in this invention, three motors sharing coils within a single rotating electric machine: motor A with a maximum rotational speed of 6000 rpm, motor B with a maximum rotational speed of 3000 rpm, and motor C with a maximum rotational speed of 1500 rpm) can be drawn as shown in Figure 37.

[0145] Each motor can be used with a torque smaller than the intersection point of the maximum current and the motor's TI characteristics. For example, a 6000rpm motor needs a torque of A or less, a 3000rpm motor needs a torque of B or less, and a 1500rpm motor needs a torque of C or less. Furthermore, considering the rotational speed, a 6000rpm motor is used when the torque is A or less and the rotational speed is between 3000 and 6000rpm, a 3000rpm motor is used when the torque is B or less and the rotational speed is between 1500 and 3000rpm, and a 1500rpm motor is used when the torque is C or less and the rotational speed is 1500rpm or less. When the torque is A or less and the rotational speed is 1500rpm or less, all motors can be used, but since the low-speed motors are more efficient, this invention switches to (uses) a 1500rpm motor.

[0146] [Other than 3-phase: Examples of 2-phase and 5-phase] In the embodiments described above, the stator coil body 18 has been shown and explained to be composed of three phases: U, V, and W. However, the motor 10 according to the present invention is characterized by its ability to switch between multiple stages of circuits in series and parallel. Therefore, the stator coil body 18 is not limited to three phases as long as it is composed of multiple phases.

[0147] Figures 38 to 40 show examples of a stator coil assembly 18 configured in two phases. In the circuit diagram of Figure 38, if the circuit section 20 is tilted to the solid line side, each coil constituting the stator coil assembly 18 is connected in series, and if it is tilted to the dashed line side, each coil is connected in parallel. Figures 39 and 40 are schematic explanatory diagrams showing the configuration of the stator coil assembly 18. In both figures, the coils are depicted with two types of lines, solid and dashed, to indicate two phases. Also, the mountain-shaped parts close to the permanent magnets 16a, indicated as S and N at the top of the figures, represent the coils that constitute the poles. Note that Figure 39 shows the state in which each coil is connected in series, and Figure 40 shows the state in which each coil is connected in parallel.

[0148] Next, Figure 41 shows an example where the stator coil assembly 18 is configured with 5 phases. In the circuit diagram of Figure 41, if the circuit section 20 is tilted to the solid line side, each coil is connected in series, and if it is tilted to the dashed line side, each coil is connected in parallel.

[0149] [Various switching variations, application examples, and variations] In the above embodiment, the number of coils and circuits is limited, but the number of coils and circuits may be increased or decreased to increase the number of combinations when connecting coils in series and in parallel. In addition to increasing the number of combinations of coil connection configurations, the appropriate rotational speed and torque may be selected according to the application, and the combinations of coil connection configurations may be limited accordingly. For example, when applying to applications where it is desired to achieve a rotational speed greater than the initial torque of power tools, it may be possible to select and switch between coil combinations that enable characteristic operation in the high-speed range, such as 4-parallel and 3-parallel.

[0150] Furthermore, in the above embodiment, the circuit section 20 is shown mechanically to make it easier to understand the switching of the coil connection configuration, but the circuit section 20 may also be provided with a similar function by a semiconductor chip.

[0151] This invention is an energy-saving device using a rotating electric machine, aiming to extend the battery life. Therefore, it does not simply propose switching coil connections, but rather proposes the power-saving effect, i.e., extended lifespan, brought about by the switching. If a high-speed motor is used in the low-speed range, it is more energy-efficient to switch to using a low-speed motor. If the motor switching can be closed within a single rotating electric machine (if motors with different specifications can be housed in an integrated configuration), the device as a rotating electric machine does not need to be large in size, and even when applied to products such as electric vehicles, it can be treated as a single rotating electric machine.

[0152] As explained above, when the present invention is applied to an electric vehicle, gear changes are performed by a coil switching device, which is voltage-controlled by the throttle control of the electric vehicle. However, when the coil arrangement is switched, the induced voltage constant changes. Therefore, when a constant voltage is applied to the same motor, for example, if the rotational speed of 1 parallel (4 coils in series) is A, then 2 parallel (two sets of 2 coils in parallel) will have a rotational speed of 2A, and 4 parallel (4 coils in parallel) will have a rotational speed of 4A, causing a sudden and abrupt change in rotational speed. Therefore, it is recommended to reduce the shock during gear changes by, for example, halving the control voltage when changing from 1 parallel to 2 parallel, or from 2 parallel to 4 parallel.

[0153] Furthermore, by using the coil switching principle described above, the maximum speed can be set arbitrarily as shown in Figure 42. For example, the maximum speed can be set between a 6000rpm motor and a 3000rpm motor for speed control. In this figure, 6000rpm is the case when, for example, 5 coils are used and all 5 coils are in parallel (5P), 3000rpm is the case when 3P+2P, 2000rpm is the case when 2P+2P+1S (i.e., a mix of series and parallel), and 1000rpm is the case when all are in series (5S). In other words, to set an upper limit on the operating speed for safety reasons, the maximum possible value of N (rotational speed) (6000 (= for example, 120 km / h) and the next value, 3000 (= 60 km / h) in the diagram above (for example, 100 km / h) are set to the maximum value for the operating conditions. Note that this setting can be removed in an emergency. The setting switching speeds will be almost uniform (20 km / h intervals between 20 km / h, 40 km / h, and 60 km / h). The MAX setting will be set between the coil connection pattern that produces the least back EMF (all coils in parallel; for example, if there are 4 coils in total, all 4 coils are in parallel) and the coil connection pattern that produces the second least back EMF (2 or more parallel coils or some are in series; for example, if there are 4 coils in total, all 2 coils are in parallel). Note that torque limits do not need to be considered as torque is proportional to current.

[0154] For example, when using all 5 coils, you can choose 5S (all in series) or 3P+2P (connecting 3 coils in parallel and 2 coils in parallel in series), and you can omit 9. Also, as mentioned above (Figure 42), the rotational speed of all in parallel (5P) is significantly (twice as much) compared to the next position and below, so it is better not to use this as well for a smoother result. Furthermore, as a variation of the 5 coil configuration, if you connect one coil (supplementary coil) in parallel to one of the coils in the series section as shown in Figure 43, the resistance of that section can be shared with the additional coil, and heat generation can be suppressed. The configuration shown in Figure 43 will be described in detail later.

[0155] Figure 43(b) shows a configuration of 5 coils arranged as 2P+2P+1S, with one additional coil added in parallel only to the 1S section. In terms of the switch circuit, the switches correspond to odd numbers as in Figure 43(a) (the additional coil is integrated with the coil being added, so no additional switch is needed for the additional coil). Alternatively, instead of adding an additional coil, the thickness of the 1S section coil can be doubled compared to the other coils, as shown in Figure 43(c).

[0156] Figure 44 shows an application example of Figure 43, in which a coil element is added in parallel to one of the five coil elements. Although six coil elements are used, two of them effectively function as a single coil element. Since this additional coil element is formed by adding one coil element in parallel to one coil element (appearing as a branch), this additional coil is referred to as a supplementary coil in this application.

[0157] In Figure 44, (A) has an auxiliary coil attached to one of the five coil elements in series, so the back EMF remains 5V, but the resistance becomes 4.5Ω, which is lower than when there is no auxiliary coil. In (B) to (E) below as well, the resistance is lower when an auxiliary coil is attached. In (B), all five coil elements are in parallel (5P), and an auxiliary coil is attached to this, so there are apparently six coil elements in parallel, the back EMF is 1V, and the resistance is 0.167Ω (=1÷6). In (C), 3P+2P+auxiliary coil is 2V, 0.66Ω (=0.33Ω+0.33Ω), in (D), 2P+2P+1S+auxiliary coil is 3V, 1.5Ω (=0.5Ω+0.5Ω+0.5Ω), and in (E), 2P+3S+auxiliary coil is 4V, 3Ω (=0.5Ω+1Ω+1Ω+0.5Ω). Pattern (E) does not need to be used because, considering the TN characteristics, the spacing of N becomes narrower (that is, in a coil switching function device (control mechanism including gear switching means), it is possible to set the desired usage pattern in advance within the range of possible connection patterns, thereby making the switching width almost uniform). Alternatively, instead of adding a supplementary coil to the coil, the cross-sectional area of ​​the coil may be doubled as shown in Figure 43(C), and the same effect can be obtained.

[0158] Figure 45 illustrates an example of operation switching using the embodiment of Figure 44 (i.e., an example of a 5-coil element connection with an auxiliary coil). Each time the coil element connection pattern is switched, it transforms into a different motor, and each motor pattern constitutes a single motor device. Therefore, there is a maximum rotational speed for each motor pattern. The graph in Figure 45 plots the TN characteristic lines of each motor pattern on a single T (torque)-N (speed) characteristic diagram. When the coil element connection patterns of Figure 44 are matched at this time, it looks like this.

[0159] In Figure 44, (A) has all five coil elements in series, so 5V ÷ 5V = 1, which corresponds to the 1st mark on the vertical axis of the graph. This is the maximum rotational speed of the motor in pattern (A). Since pattern (A) uses all five coil elements in series, it is the motor with the smallest maximum rotational speed among the motors inherent in the motor device. In this application, in the following explanation, the 1st mark will be considered as 20 km / h. In (B), all five coil elements are in parallel, so the voltage is 1V, so 5V ÷ 1V = 5, which corresponds to the 5th mark on the vertical axis (i.e., 100 km / h). This is the maximum rotational speed of the motor in pattern (B). And since all five coils are used in parallel, it is the motor with the largest maximum rotational speed among the motors inherent in the motor device. In (C), the voltage is 2V, so 5 ÷ 2 = 2.5, which corresponds to the 2.5th mark on the vertical axis (50 km / h. The maximum rotational speed of the motor in pattern (C)). (D) is 3V, so 5÷3=1.7, which corresponds to 1.7 divisions on the vertical axis (34km / h. Maximum rotational speed for pattern (D)). Then, for (E) it's 4V, so 5÷4=1.25 (25km / h. Maximum rotational speed for the motor in pattern (E)). In that case, the range between the maximum rotational speed of motor 1 and rotational speed 0 in pattern (A) becomes 1, the range between the maximum rotational speeds of (A) and (D) becomes 1.7-1=0.7, the range between the maximum rotational speeds of (D) and (C) becomes 0.8, and the range between (C) and (B) becomes 2.5. In other words, the gap between (C) and (B) becomes significantly larger. This causes a shock for both the operator and the motor device. If the maximum speed is not expected under normal conditions, a limiter can be set before reaching the maximum speed. Therefore, the inventor proposes setting the limiter before the rotational speed at which this significantly larger range occurs (for example, at a scale of 3.5, which corresponds to 70 km / h). In that case, the scale range between the maximum rotational speed of pattern (C) and the rotational speed at the limiter position becomes 1.0, and the range from 0 to (A), (A) to (D), (D) to (C), and (C) to the limiter becomes approximately 1.0, thus reducing the gear shift shock for both the operator and the device. The range between these maximum rotational speeds should be approximately equal. The motor's coil element switching pattern should be selected so that the range is (1 ± 0.5) times the maximum rotational speed when all coil elements are connected in series.

[0160] On the other hand, it is sufficient to select a motor with a coil element switching pattern that has a width of (1 ± 0.5) times the maximum rotational speed when all coil elements are connected in series. Therefore, motor patterns that do not meet this condition (for example, pattern (E) has a scale corresponding to the maximum rotational speed of 1.25, so the width between (A) and (E) is 0.25, and the interval between (E) and (D) is also 0.45, which is outside the range of 1 ± 0.5) can be left unused. Such fine switching can be omitted, simplifying switching control, and the switching interval corresponding to the maximum rotational speed becomes almost uniform, reducing the driver's subjective burden. Incidentally, the horizontal axis of the graph in Figure 45 has scales up to 6, and they are connected by characteristic lines as shown in the figure. This is the effect of the auxiliary coil, which makes the slope of the TN characteristic gentler.

[0161] Furthermore, although the MAX display is also described in Figure 42, the example in Figure 42 also shares the common point of narrowing the gap between the maximum rotational speeds. In addition, variations in the coil connection switching used in this invention are explained in Figures 46 to 49. Figure 46 shows the use of six coils for each phase. The left side of the figure shows a configuration where switches are connected between all six coils, while the right side shows an example where the switches are reduced. If all connection methods up to 6P are chosen with six coils for each phase, 15 switches between coils are required. However, as in this example, by not using 6P and using a three-stage switching system of 6S, 2P3S, and 3P2S, only nine switches are needed, a significant reduction. This is because the switches at both ends (c between coils (1) and (2) and e between coils (5) and (6)) that would be needed in a fully series connection are eliminated, and consequently, the switches a, b, d, and f connected between the coils at both ends can also be reduced.

[0162] Furthermore, the difference in maximum rotational speed (= speed difference) between 6-coil and 2P3S, and between 2P3S and 3P2S, becomes uniform. This effect can also be obtained with 12 coils, but for coil counts of 12 or less, this uniformity can be used for 6-coil and 12-coil configurations.

[0163] Figure 47 shows an example of performing four-stage switching using 12 coils for each phase, following the example in Figure 46, by thinning out the inter-coil switches to achieve a total of four switching stages: all in parallel (12S), 2P6S, 3P4S, and 4P3S. This example is not used when all coils are in parallel. The upper part of the figure shows a case where switches are installed between all 12 coils (comparative example), and the lower part shows an example where switches are thinned out (this example).

[0164] In the case of all-series (12S) configuration, switches F, G, H, I, and J are closed and the other switches are opened. In the case of 2P6S, switches C, F, G, M, I, and J are closed and the other switches are opened. In the case of 3P4S, switches B, D, F, H, J, L, and N are closed and the other switches are opened. In the case of 4P3S, switches A, C, E, G, I, K, M, and O are closed and the other switches are opened. In this way, the 36 switches that would normally be used to switch the 12 coils for each phase become unnecessary, with 19 switches (the number of lowercase letters in the diagram) becoming sufficient, and only 15 switches are needed.

[0165] Maximum rotational speed (N) (This refers to the maximum rotational speed of each motor when considering that a different motor is created for each coil switch. This can be determined by changing how the coils of each motor (for example, 12 coils in total) are divided (how they are connected in parallel). If divided into 12, it becomes 12S, and 12 ÷ 12 = N=1. If divided into groups of 3, it becomes 4P3S, and 12 ÷ 3 (the number of coils connected in series is 3) = N=4. If divided into groups of 4, it becomes 3P4S, and 12 ÷ 4 = N=3. If divided into groups of 6, it becomes 2P6S, and 12 ÷ At 6, N=2, and as a result, N becomes evenly distributed within the ranges of 0-1, 1-2, 2-3, and 3-4 (see Figure 48). Note that if six parallel configurations of two coils each are created in the 12-coil configuration, the maximum rotational speed becomes 6P2S, resulting in N=6, which deviates slightly from the even range and falls outside the best mode, but this invention does not exclude this (in this case, five-stage switching becomes possible. Also, the number of switches between the 12 coils in series is 7 instead of 11). Note that 12P is not used in this example because the difference in the maximum rotational speed intervals is too large, and considering the operating shock.

[0166] Adopting the patterns shown in Figures 46 and 47 significantly reduces the number of switches. This reduction in the number of switches suppresses voltage drop, increasing motor efficiency. Furthermore, since less current is needed to produce the same torque, battery consumption is reduced.

[0167] Figure 49 illustrates the reinforcement of the coil body of a coreless motor using a cylindrically molded stator coil body. The coreless motor of the embodiment of the present invention has a rotating shaft 14 in the center of the motor case (housing 12) that surrounds the outer circumference, with a portion of it protruding outward from the case flange 12b to serve as the output shaft. The rotating shaft 14 is inserted through a cylindrical sleeve 83 formed in the case flange 12b inside the housing 12 and is supported by a bearing 12a.

[0168] The innermost part of the rotating shaft 14 protrudes from the cylindrical sleeve 83, and a hub 84 is attached to the outer surface of the protrusion. A rotor 16 is attached concentrically to the outer circumference of the cylindrical sleeve 83 via the hub 84. The rotor 16 is cylindrical in shape, but its wall surface is double-layered, forming an outer yoke 16c on the outer circumference side and an inner yoke 16b on the inner circumference side. The outer yoke 16c and inner yoke 16b are folded back at the end face of the hub 84, and an annular gap 82 opens at the other end (the end on the case flange 12b side). A permanent magnet 16a is positioned and fixed in the annular gap 82, particularly on the inner circumference of the outer yoke 16c. A cylindrical stator coil body 18 is positioned in the annular gap 82 between the permanent magnet 16a and the inner yoke 16b.

[0169] The cylindrical stator coil body 18 is formed by braiding multiple insulated conductors into a cylindrical shape. As explained in Figure 4, this coil body is made up of multiple individual coils used in this invention, connected for each phase with a switch mechanism in between. One end of the stator coil body 18 (conductor wiring side) is covered by a donut-shaped stator disc 85 arranged radially, and is attached to the case flange 12b via bolts or the like. A coil wiring board is formed on the stator disc 85. 86 is a wiring connector and is provided near the wiring board. A fixing ring 87 is also provided on the outer circumference of the stator disc 85.

[0170] The stator coil body 18, configured in this way, has its free end inserted into the annular gap 82, and a reinforcing ring 81 is attached to the free end of the stator coil body 18, which is thus cantilevered. As a result, the reinforcing ring 81 is fixed in place together with the fixed stator coil body 18, and the outer yoke 16c, inner yoke 16b, and magnet 16a rotate together around it.

[0171] The reinforcing ring 81 has, for example, an L-shaped cross-section and consists of a portion that receives the thickness of the tip of the free end of the stator coil body 18 and a portion that protects the outer surface of the stator coil body 18. Therefore, the reinforcing ring 81 is formed by machining a ring material having a rectangular cross-section that is slightly thicker than the thickness of the stator coil body 18 so that the L-shaped step described above is created on the inner surface side. The reinforcing ring 81 is formed from a metal material or resin material that is considered to be a non-magnetic material.

[0172] In a coreless motor configured in this way, a donut-shaped magnetic field is formed between the outer yoke 16c and the inner yoke 16b. By supplying a predetermined current to the stator coil body 18, the rotor 16 rotates, and the rotating shaft 14 rotates through the hub 84. The rotor 16, which rotates simultaneously with the rotation of the rotating shaft 14, generates a counter-torque on the stator coil body 18. Although one end of the stator coil body 18 is firmly fixed by the stator disc 85, etc., it is expected that the free end, which is inserted into the annular gap 82 of the rotor 16, will be distorted due to the counter-torque action. However, in this embodiment, it is constrained by the reinforcing ring 81, and the circular shape is not disturbed. The reinforcing ring 81 can be easily attached by making it L-shaped, and can also be easily attached even if there are irregularities by using adhesive resin. Furthermore, by forming the reinforcing ring 81 from metal or resin, it is possible to make it a form that can easily and simply prevent distortion.

[0173] Furthermore, in this example, a reinforcing sheet 18a is attached to the inside and / or outside of the cylindrical stator coil body 18 as shown in the figure. Since the purpose of this reinforcing sheet 18a is to protect the strength of the molded fibrous material, a film sheet of a fiber-reinforced resin, such as carbon fiber reinforced plastic (CFRP), which is an insulating high-strength resin, is laminated and attached to the coil body. It should be noted that this film layer is thinner than the coil body. This prevents the coil body from being damaged even if it comes into contact with the yoke or magnet during rotation.

[0174] As described above, the present invention allows for easy and smooth gear switching of a moving body by switching coil patterns, while simultaneously achieving power saving effects on the battery. Finally, a method for even smoother switching will be explained in Figure 50.

[0175] Figure 50 shows the system diagram illustrating the connections between the controller 31, driver 40, coil connection pattern switching device 80, and motor 10. First, the controller 31 determines the torque output from the motor 10 based on throttle information and speed information. Throttle information is the throttle opening; for example, it is 0% when the throttle is closed and 100% when the throttle is full. The controller 31 automatically or manually selects the gear value. 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.

[0176] The driver 40 controls the motor so that the motor current value matches the command value from the controller 31, and also provides the controller 31 with the motor's rotational speed N as speed information. Regarding gear selection, a low gear is used when the rotational speed is low, and a higher gear is used when the rotational speed is high. Torque is determined according to a torque map pre-stored in the controller 31. This torque map consists of, for example, multiple throttle states and torque values ​​for each of multiple speeds, and the torque that should actually be output is calculated by interpolation calculation from the actual throttle state, speed and this torque map. For example, the torque map stored in the controller 31 contains information for all six types of throttle states and speeds: closed (0%), 20% open, 40% open, 60% open, 80% open, and full throttle (100%). The controller 31 then calculates the torque value from the speed N, the throttle information and this torque map. If the throttle value is anything other than the six types mentioned above (0%, 20%, 40%, 60%, 80%, 100%), the torque value is calculated by interpolation calculation.

[0177] As described above, gear switching is performed by switching the coil connection pattern using the coil connection pattern switching device 80. In this way, the gears are switched according to the rotational speed.

[0178] The controller 31 calculates the current value required for each gear to produce the predetermined torque to be output and instructs the driver 40 accordingly. The current command to the driver 40 is executed simultaneously with the gear switching instruction, so the output torque fluctuation during gear switching is very small, and smooth switching is achieved. In other words, a current command that does not change the torque before and after switching is given simultaneously with the switching, resulting in smooth switching. For example, assuming a system where the torque constant is 0.4 Nm / A in 1st gear and 0.2 Nm / A in 2nd gear, if the torque to be output in 1st gear is 1 Nm, the controller 31 instructs the driver 40 to issue a current command of 2.5 A. If the rotational speed increases and it becomes necessary to switch to 2nd gear, the controller 31 changes the current command given to the driver 40 from 2.5 A to 5 A at the same time as the switching instruction. As a result, the torque output from the motor 10 is maintained at 1 Nm before and after switching, and smooth switching is achieved. [Explanation of Symbols]

[0179] 10…Motor, 12…Housing, 12a…Bearing, 12b…Case flange, 14…Rotating shaft, 16…Rotor, 16a…Permanent magnet, 16b…Inner yoke, 16c…Outer yoke, 18…Stator coil, 18a…Reinforcement sheet, 20 (20U, 20V, 20W)…Circuit section, 22…Control unit, 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, U2...Second coil, U3...Third coil, U4...Fourth coil, V1...First coil, V2...Second coil, V3...Third coil, V4...Fourth coil, W1...First coil, W2...Second coil, W3...Third coil, W4...Fourth coil, 40...Driver, 50...Battery, 60, 70...Cable, 80...Coil connection pattern switching device, 81...Reinforcement ring, 82...Annular gap, 83...Cylindrical sleeve, 84...Hub, 85...Stator disc, 86...Wiring connector, 87...Fixing ring.

Claims

[Claim 1] A rotating electric machine for an electric vehicle, which is incorporated into an apparatus having a battery, a driver, and a first wiring path from the battery to the driver, and is connected to the driver by a second wiring path, The rotating electric machine is a coreless motor having a non-rotating cylindrical coil body housed in a motor housing with one end fixed and the other end being a free end, and a permanent magnet located on a surface of the coil body, spaced apart from the coil body, and further having a controller attached thereto; The cylindrical coil body is formed of three or more coils for each phase, and is combined into a plurality of phases. By switching the coil connections, three or more types of motors with different maximum rotation speeds are built in so that the coils are shared, and the coil connection switching patterns are (a) all in series, (b) all in parallel, and (c) series-parallel connection, and the coil connection pattern can be selected so that the maximum rotation speed changes depending on the torque, and a motor with high motor efficiency at any rotation speed is automatically selected depending on the load. Each of the coils is made of the same specification and is wound with an insulated conductor. The controller determines a torque to be output based on throttle information and speed information of the electric vehicle, and instructs the driver on a current value required to generate the torque for each coil connection pattern; A rotating electric machine for an electrically-driven mobile body, characterized in that if the motors have the same rotation speed or torque, the rotating electric machine automatically switches to the motor having the lower rotation speed specification.

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