JP4351792B2 - Alternator that also serves as a starter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an alternator that also serves as a starter having a function as an electric motor for starting an engine and a function of operating as a generator after the engine is started.
[0002]
[Prior art]
The automobile is provided with a starter for starting the engine and an alternator that is driven by the engine to generate electric power. These starter and alternator are separate parts. Conventionally, brushed DC motors have been used as starters and alternators.
[0003]
[Problems to be solved by the invention]
However, in the case of the conventional configuration, since the starter and the alternator are separate components, the number of components is increased, and it takes time and effort to assemble, resulting in a complicated configuration.
[0004]
As a configuration for solving this problem, a configuration in which an electric motor used as an engine starter is also used as an engine alternator can be considered. In the case of this configuration, the starter motor needs to have a characteristic of generating a large torque necessary to start the engine. When an electric motor having such characteristics is operated as an engine alternator (generator) in a high-speed rotation region, the electric power generation (induced) voltage of the electric motor becomes considerably high.
[0005]
When the induced voltage of the alternator, that is, the electric motor is increased, an expensive element having a high withstand voltage must be used as a switching element used in the drive circuit of the electric motor, which may increase the manufacturing cost. Further, since the voltage of the battery mounted on the automobile is a low voltage of about 12V, 24V or 36V, a step-down circuit is required when charging the battery with an alternator having a high induced voltage.
[0006]
Therefore, an object of the present invention is to use a starter that can prevent an induced voltage from increasing when the motor is used as an alternator and operates in a high-speed rotation region while the motor used as the engine starter is also used as an alternator of the engine. To provide an alternator.
[0007]
[Means for Solving the Problems]
An alternator also serving as a starter of the present invention includes a rotor having a rotating shaft directly connected to or coupled to an engine driving shaft and having a permanent magnet, and a stator comprising a stator core and a stator coil wound around the stator core. When the engine is started, the motor is operated as a motor, and after the engine is started, the permanent magnet type motor is operated as a generator. In the axial relationship between the rotor and the stator, With a changing mechanism, The mechanism has means for urging the rotor and the stator to be positioned at a position where the facing area of the rotor and the stator is reduced when not energized and when operated as the generator, When energized to operate as the electric motor, the rotor and the stator are positioned at a position where the opposing area of the rotor and the stator is substantially maximized by the magnetic attractive force between the rotor and the stator. It is configured However, it has characteristics.
[0008]
According to the above configuration, the permanent magnet type electric motor is used as an engine starter and alternator. When the permanent magnet type motor is operated in a predetermined rotational speed region as an alternator (generator), the field magnetic flux between the rotor and the stator is reduced, so that the induced voltage of the permanent magnet type motor does not increase. .
[0011]
In this configuration Before More preferably, the rotor is composed of a magnetic material and a permanent magnet embedded in the magnetic material.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment in which the present invention is applied to an automobile will be described below with reference to FIGS. First, in FIG. 3 schematically showing the overall configuration of an automobile, an engine 2 is mounted on an automobile 1 that is a vehicle. The engine 2 is configured to drive the axles 6 and 6 of the rear wheels 5 and 5 via the transmission 3 and the differential gear 4. The axles 8 and 8 of the front wheels 7 and 7 of the automobile 1 are not driven.
[0013]
Further, the automobile 1 is equipped with a permanent magnet type synchronous motor 9 that constitutes an alternator that also serves as a starter of the engine 2. As shown in FIGS. 1 and 2, the permanent magnet type synchronous motor 9 includes a stator 9a having a plurality of phases, for example, three-phase stator coils 9U, 9V and 9W, and a permanent magnet rotor 9b. The rotor 9b is configured by embedding a permanent magnet 9d in a rotor yoke 9c made of a magnetic material.
[0014]
The rotating shaft 9e of the rotor 9b of the permanent magnet type synchronous motor 9 is directly connected to or connected to the drive shaft (that is, the output shaft) of the engine 2. Thereby, the permanent magnet type synchronous motor 9 constitutes a starter (electric motor) for starting the engine 2 and is configured to operate as an alternator (generator) after the engine 2 is started. That is, the permanent magnet type synchronous motor 9 constitutes an alternator that also serves as a starter for the engine 2.
[0015]
Furthermore, as shown in FIG. 3, the car 1 is equipped with a rechargeable battery 10 made of a lead storage battery or the like. Electric power is exchanged between the battery 10 and the permanent magnet type synchronous motor 9 via a control device 11 described later.
[0016]
Now, a specific configuration of the control device 11 will be described with reference to FIG. The inverter circuit 12 as a drive circuit of the permanent magnet type synchronous motor 9 is configured by connecting NPN transistors 13U, 13V, 13W and 14U, 14V, 14W as six switching elements in a three-phase bridge connection. The flywheel diodes 15U, 15V, 15W and 16U, 16V, 16W are connected between the respective collectors and emitters, and thus have three arms 17U, 17V and 17W. Note that the switching element is not limited to a transistor, and an appropriate element such as a MOS-FET or IGBT is used depending on the situation.
[0017]
The input terminals 18 and 19 of the inverter circuit 12 are connected to the DC buses 20 and 21, and the output terminals 22U, 22V and 22W are connected to one terminal of each of the stator coils 9U, 9V and 9W of the permanent magnet type synchronous motor 9. Has been. The other terminals of the stator coils 9U, 9V and 9W are connected in common. The DC bus 21 is connected to the negative terminal of the battery 10, and a capacitor 23 is connected between the DC buses 20 and 21.
[0018]
The chopper circuit 24 includes, for example, NPN transistors 25 and 26 and diodes 27 and 28 as two switching elements (a plurality of switching elements may be used). The collector of the transistor 25 of the chopper circuit 24 is connected to the DC bus 20, and the emitter is connected to the collector of the transistor 26. The emitter of the transistor 26 of the chopper circuit 24 is connected to the DC bus 21. Diodes 27 and 28 are connected between the collectors and emitters of the transistors 25 and 26, respectively. The neutral point of the chopper circuit 24 is connected to the positive terminal of the battery 10 via the reactor 29. In this case, the reactor 29 is configured by winding a coil around a core.
[0019]
Further, the battery voltage detector 30 is connected in parallel to the battery 10 and is configured to detect a voltage between terminals of the battery 10. The main circuit voltage detector 31 is connected in parallel to the capacitor 23 and detects the voltage across the terminals of the capacitor 23 (main circuit voltage). The position detector 32 is disposed in the permanent magnet type synchronous motor 9 and includes a resolver that detects the position of the rotor of the permanent magnet type synchronous motor 9.
[0020]
The output terminals of the battery voltage detector 30, the main circuit voltage detector 31, and the position detector 32 are connected to the input ports of the control circuit 33 constituted by a microcomputer or the like. The output ports of the control circuit 33 are connected to the input terminals of photocoupler base drive circuits 34 and 35, respectively. The control operation of the control circuit 33 will be described later. The output terminals of the base drive circuit 34 are connected to the bases of the transistors 13U to 13W and 14U to 14W of the inverter circuit 12, respectively. The output terminals of the base drive circuit 35 are connected to the transistors 25 and 26 of the chopper circuit 24, respectively. Each is connected to the base.
[0021]
Next, the operation of this embodiment will be described. First, a case where the permanent magnet type synchronous motor 9 is operated as a starter (motor) will be described.
[0022]
The control circuit 33 puts the chopper circuit 24 into a non-operating state when the voltage between the terminals of the battery 10 detected by the battery voltage detector 30 is the rated voltage. As a result, the DC voltage of the battery 10 is applied to the capacitor 23 via the reactor 29 and the diode 27, and the capacitor 23 is charged to a voltage suitable for the input voltage of the inverter circuit 12. Further, the control circuit 33 gives a PWM signal to the base of the base drive circuit 35 when the voltage across the terminals of the battery 10 detected by the battery voltage detector 30 is lower than the rated voltage, thereby providing the negative transistor 26 of the chopper circuit 24. A base signal is applied to the transistor 26, and the transistor 26 is turned on / off according to the duty of the PWM signal.
[0023]
In the chopper circuit 24, when the transistor 26 is turned on, a current flows from the battery 10 to the reactor 29 through the path of the reactor 29 and the transistor 26. Next, when the transistor 26 is turned off, the energy accumulated in the reactor 29 is reduced. The voltage is discharged through the diode 27, and thus the boosted voltage is applied to the capacitor 23.
[0024]
In this case, the voltage step-up rate is determined by the duty of the PWM signal, and the step-up rate increases as the duty of the PWM signal increases. The control circuit 33 determines the duty of the PWM signal according to the voltage between the terminals of the battery 10, whereby the capacitor 23 is charged to a voltage suitable for the input voltage of the inverter circuit 12. Thus, the chopper circuit 24 and the reactor 29 operate as a step-up chopper at this time.
[0025]
When the starter signal is given to the control circuit 33, the control circuit 33 generates an energization timing signal based on the position detection signal from the position detector 32 and gives it to the base drive circuit 34. The base drive circuit 34 Accordingly, base signals are sequentially applied to the bases of the transistors 13U to 13W and 14U to 14W of the inverter circuit 12, and the transistors 13U to 13W and 14U to 14W are sequentially turned on and off.
[0026]
Thereby, an alternating current according to the position of the rotor 9b flows through the stator coils 9U to 9W of the permanent magnet type synchronous motor 9, and the rotor 9b starts to rotate. When the permanent magnet type synchronous motor 9 is started, the output shaft of the engine 2 connected to the shaft is rotationally driven, and the engine 2 is started. That is, at this time, the permanent magnet type synchronous motor 9 functions as a starter of the engine 2.
[0027]
In the permanent magnet type synchronous motor 9 of this embodiment, as shown in FIG. 2, the permanent magnet 9d of the rotor 9b is in the d-axis direction, and the permeability of the permanent magnet 9d is almost the same as that of air (there is a gap). Therefore, the magnetic flux hardly passes in the d-axis direction compared to the q-axis direction (note that the d-axis is the permanent magnet field direction and the q-axis is orthogonal to the d-axis). Direction). For this reason, the rotor 9b has the same structure as the convex pole machine structure, and generates reluctance torque in the same manner as the reluctance motor. The torque T of the permanent magnet type synchronous motor 9 is expressed by the following equation.
[0028]
T = P (φiq + (Ld−Lq) idiq) (1)
However, P is the number of poles, φ is a permanent magnet magnetic flux, Ld is a d-axis inductance, Lq is a q-axis inductance, id is a d-axis current, and iq is a q-axis current.
[0029]
In the above formula (1), the first term in parentheses is the torque due to the permanent magnet magnetic flux and the q-axis current, and the second term represents the reluctance torque. If the torque of the first term and the reluctance torque of the second term are added together, the torque generated by the electric motor can be increased. That is, if the motors have the same torque, the size can be reduced and the amount of permanent magnets used can be reduced. In order to generate the reluctance torque, the current in the field direction, that is, the d-axis current is controlled in addition to the normal q-axis current.
[0030]
Thus, since the permanent magnet type synchronous motor 9 in which the permanent magnet 9d is embedded in the rotor yoke 9c of the rotor 9b can generate reluctance torque, it can generate a large torque as a starter of the engine 2 and is mounted on an automobile. Very preferable as an electric motor. Further, since the permanent magnet 9d does not scatter during high-speed rotation, this is also very preferable as an electric motor mounted on an automobile.
[0031]
Next, the case where the permanent magnet type synchronous motor 9 is operated as a generator (alternator) will be described.
[0032]
When the engine is started, the control circuit 33 stops supplying base signals to the bases of the transistors 13U to 13W and 14U to 14W of the inverter circuit 12 and turns them all off, so that the inverter circuit 12 is deactivated. Put it in a state. When the engine 2 is started, this time, the shaft of the permanent magnet type synchronous motor 9, that is, the rotor is rotationally driven by the output shaft of the engine 2, and a voltage is induced in the stator coils 9 U to 9 W. The AC voltage is converted into a DC voltage by the flywheel diodes 15U to 15W and 16U to 16W of the inverter circuit 12 functioning as a full-wave rectifier circuit and applied to the capacitor 23. That is, at this time, the permanent magnet type synchronous motor 9 functions as a generator.
[0033]
By the way, the rotational speed of the output shaft of the engine 2 changes depending on the degree of depression of the accelerator of the automobile. Accordingly, the voltage (power generation voltage) induced in the stator coils 9U to 9W of the permanent magnet type synchronous motor 9 also varies depending on the rotational speed of the output shaft of the engine 2, and the DC voltage applied to the capacitor 23 is also changed. Also changes high and low.
[0034]
In this case, after the engine 2 is started, the rotation speed of the output shaft changes from an idle rotation speed to a high-speed rotation area (for example, 7000 to 8000 rpm) that is a predetermined rotation speed area of several thousand rpm. On the other hand, when starting the engine 2, the permanent magnet type synchronous motor 9 as a starter is rotated at a low speed, for example, about 500 to 1000 rpm. Therefore, the magnitude of the voltage induced in the permanent magnet type synchronous motor 9 as a generator is about 10 times the magnitude of the voltage applied to the permanent magnet type synchronous motor 9 as a starter, which is a considerably high voltage. . If such a high voltage is generated, the transistors 13U, 13V, 13W, 14U, 14V, and 14W constituting the inverter circuit 12 that is the drive circuit of the permanent magnet type synchronous motor 9 have high breakdown voltage. It must be used and the manufacturing cost is high.
[0035]
Therefore, in the present embodiment, the control circuit 33 is configured to execute field-weakening control on the permanent magnet type synchronous motor 9 when operating the permanent magnet type synchronous motor 9 as a generator in the high speed rotation region. ing. As a result, the field magnetic flux between the rotor 9b and the stator 9a is reduced, and the magnitude of the voltage induced in the permanent magnet type synchronous motor 9 is reduced. In this case, the control circuit 33 constitutes the magnetic flux reducing means of the present invention. What is necessary is just to comprise so that well-known control may be used suitably as said field-weakening control.
[0036]
Since the permanent magnet type synchronous motor 9 of the present embodiment is a motor that generates reluctance torque as described above, the amount of magnetic flux of the permanent magnet can be reduced by using this reluctance torque, and induction of the motor The voltage can be lowered. That is, in order to generate the reluctance torque, in addition to the normal q-axis current, the d-axis current, which is the current in the field direction, may be controlled (field weakening control) so as to flow in the direction of decreasing the field magnetic flux. In the case of the present embodiment, when the permanent magnet type synchronous motor 9 is operated as a generator, the field weakening control is executed by the control circuit 33 when operating in the high speed rotation region. Yes.
[0037]
As a result, in this embodiment, the voltage generated by the permanent magnet type synchronous motor 9 that is a generator is reduced, so that the transistors 13U, 13V, and 13W that constitute the inverter circuit 12 that is a drive circuit of the permanent magnet type synchronous motor 9 are used. , 14U, 14V, and 14W do not need to use a high withstand voltage, and the manufacturing cost can be reduced.
[0038]
In this embodiment, when the permanent magnet type synchronous motor 9 is operated as a generator, the voltage control operation described below, that is, the voltage between terminals of the capacitor 23 is lowered or raised by the chopper circuit 24. Thus, a voltage control operation to be applied to the battery 10 is also appropriately executed.
[0039]
Specifically, when the voltage across the terminals of the capacitor 23 (main circuit voltage) detected by the main circuit voltage detector 31 is higher than the rated voltage of the battery 10 (the generated voltage of the permanent magnet type synchronous motor 9 is When it is high), the base signal is supplied to the base of the transistor 25 on the positive side of the chopper circuit 24 by supplying the PWM signal to the base drive circuit 35, and the transistor 25 is turned on / off according to the duty of the PWM signal.
[0040]
In the chopper circuit 24, when the transistor 25 is turned on, the voltage between the terminals of the capacitor 23 is applied to the battery 10 through the reactor 29 only during the on-time of the transistor 25. The voltage between terminals is stepped down and applied. In this case, the voltage step-down rate is determined by the duty of the PWM signal, and the step-down rate increases as the duty of the PWM signal decreases. The control circuit 33 is configured to determine the duty of the PWM signal in accordance with the voltage across the terminals of the capacitor 23, whereby the battery 10 is charged with an appropriate voltage. Thus, the chopper circuit 24 and the reactor 29 are configured to operate as a step-down chopper at this time.
[0041]
On the other hand, the control circuit 33 detects when the voltage across the terminals of the capacitor 23 (main circuit voltage) detected by the main circuit voltage detector 31 is lower than the rated voltage of the battery 10 (when the generated voltage of the permanent magnet type synchronous motor 9 is low). Then, the chopper circuit 24 is brought into a non-operating state. Here, making the chopper circuit 24 non-operating means that the transistors 25 and 26 are not repeatedly turned on and off, and here, the transistor 25 is turned on.
[0042]
Further, the control circuit 33 gives a base signal to the bases of the negative side transistors 14U to 14W of the inverter circuit 12 by giving a PWM signal to the base drive circuit 34, and the transistors 14U to 14W are set to the duty of the PWM signal. It is turned on and off accordingly. In this case, in the inverter circuit 12, the transistor 14U is turned on / off when the current flows from the stator coil 9U of the permanent magnet type synchronous motor 9, and the transistor 14V is turned on / off when the current flows from the stator coil 9V. When the current flows from the stator coil 9W, the transistor 14W is turned on / off.
[0043]
In the inverter circuit 12, for example, when the transistor 14U is turned on, a voltage induced in the stator coil 9U and the stator coil 9V or 9W causes the stator coil 9U, the transistor 14U, the freewheel diode 16V or 16W, and the stator coil 9V or 9W. Circulated current flows through the path of, and energy is accumulated in the stator coil 9U and the stator coil 9V or 9W. Next, when the transistor 14U is turned off, it is accumulated in the stator coil 9U and the stator coil 9V or 9W. The released energy is released through the free wheel diode 15U, and the boosted voltage is applied to the capacitor 23. In this case, the voltage step-up rate is determined by the duty of the PWM signal, and the step-up rate increases as the duty of the PWM signal increases. The control circuit 33 is configured to determine the duty of the PWM signal according to the voltage between the terminals of the battery 10. As a result, the capacitor 23 is charged to a voltage suitable for charging the battery 10.
[0044]
Further, the principle of boosting by turning on and off the transistors 14V and 14W of the inverter circuit 12 is the same as that when the transistor 14U is turned on and off. Therefore, at this time, the inverter circuit 12 causes the stator coils 9U to 9W to be connected. It functions as a step-up chopper as a reactor. In addition, when functioning as a step-up chopper in this way, the rotational speed of the engine 2 is low and the generated voltage of the permanent magnet type synchronous motor 9 is low.
[0045]
According to this embodiment having such a configuration, the rotary shaft 9e of the permanent magnet type synchronous motor 9 is directly connected to the output shaft of the engine 2, and the permanent magnet type synchronous motor 9 is connected to the engine 2 when the engine 2 is started. It was configured to operate as a drive starter, and to operate as a generator (alternator) for charging the battery 10 driven by the engine 2 after the engine 2 was started. As a result, a single permanent magnet type synchronous motor 9 is used as a generator for charging the starter of the engine 2 and the battery 10, that is, an alternator that also functions as a starter. Compared to the conventional configuration for mounting, the mounting space of the automobile 1 can be reduced. Since there is no need to provide a conventional clutch between the output shaft of the engine 2 and the shaft of the permanent magnet type synchronous motor 9, the mounting space of the automobile 1 can be further reduced.
[0046]
Further, in the above embodiment, when the permanent magnet type electric motor 9 is operated as an alternator (generator) in the high-speed rotation region by the control circuit 33, the field weakening control is executed, so that the space between the rotor 9b and the stator 9a is controlled. Control was made to reduce the field flux. Thereby, when making it operate | move as a generator in a high speed rotation area | region, it can prevent that the induced voltage of the permanent magnet type motor 9 becomes high. As a result, it is not necessary to use transistors 13U, 13V, 13W, 14U, 14V, and 14W that constitute the inverter circuit 12 that is a drive circuit for the permanent magnet type synchronous motor 9, so that it is not necessary to use a high breakdown voltage. Can be reduced.
[0047]
In the case of the above embodiment, the rotor 9b of the permanent magnet type motor 9 is composed of the rotor yoke 9c made of a magnetic material and the permanent magnet 9d embedded in the rotor yoke 9c. The reluctance torque can be generated, and a large torque can be generated as a starter of the engine 2. Further, since the permanent magnet 9d is not scattered from the rotor 9b when the permanent magnet type synchronous motor 9 is rotated at a high speed, this is also a very preferable configuration as an electric motor mounted on an automobile.
[0048]
FIG. 4 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals. In the second embodiment, as shown in FIG. 4, the rotor 36 of the permanent magnet type synchronous motor 9 includes a rotor yoke 37 made of a magnetic material and a permanent magnet 38 embedded in the rotor yoke 37. At the same time, a gap portion 37 a for increasing the magnetic field direction magnetic resistance of the permanent magnet 38 is provided inside the rotor yoke 37. The other configuration is the same as that of the first embodiment.
[0049]
Therefore, in the second embodiment as well, it is possible to obtain substantially the same operational effects as in the first embodiment. In particular, according to the second embodiment, since the gap portion 37a for increasing the magnetic field direction magnetic resistance of the permanent magnet 38 is provided inside the rotor yoke 37, the reluctance torque can be further utilized, and the engine 2 The torque when starting can be increased. Further, since the amount of magnetic flux of the permanent magnet can be reduced, the induced voltage can be reduced.
[0050]
FIG. 5 shows a third embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals. In the third embodiment, as shown in FIG. 5, the rotor 39 of the permanent magnet type synchronous motor 9 is composed of a rotor yoke 40 made of a magnetic material and a permanent magnet 41 disposed on the outer periphery of the rotor yoke 40. It is composed. That is, the permanent magnet type synchronous motor 9 of the third embodiment is a normal permanent magnet type synchronous motor that does not generate reluctance torque. The other configuration is the same as that of the first embodiment.
[0051]
Therefore, in the third embodiment as well, it is possible to obtain substantially the same operational effects as in the first embodiment. In the case of the third embodiment, when a normal permanent magnet type synchronous motor 9 that does not generate a reluctance torque is operated as a generator in a high-speed rotation region, a well-known field weakening control is executed, so that the rotor 39 And the magnetic field flux between the stator 9a is reduced.
[0052]
6 and 7 show a fourth embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals. In this 4th Example, as shown in FIG.6 and FIG.7, the stator 9a of the permanent magnet type | mold synchronous motor 42 was provided so that a movement to a rotating shaft direction was possible with respect to the rotor 9b.
[0053]
Specifically, the housing 43 of the permanent magnet type synchronous motor 42 includes a substantially cup-shaped motor frame 44 and a bearing bracket 45 that closes the opening of the motor frame 44. The rotating shaft 9e of the rotor 9b is rotatably supported by a bearing 46 provided on the bottom wall portion of the motor frame 44 and a bearing 47 provided on the bearing bracket 45. A pin 48 is disposed at a portion along the peripheral wall portion in the motor frame 44, and the stator 9 a is supported by the pin 48 so as to be movable in the axial direction via bearings 49 and 49. The bearings 49 and 49 are bearings such as linear ball bearings or sliding bearings, and are attached to the stator 9a.
[0054]
And the stator 9a is urged | biased by the coiled spring 50 provided in the pin 48 so that it may move to the right side (direction away from the rotor 9b) in FIG. In the state shown in FIG. 6, the field magnetic flux between the rotor 9b and the stator 9a of the permanent magnet type motor 42 is configured to decrease. When the permanent magnet motor 42 is not energized and is operated as a generator, the current flowing through the stator coils 9U, 9V, and 9W is small, so that the state shown in FIG. 6 is obtained. ing. Thereby, when the permanent magnet type motor 42 is operated as a generator, the field magnetic flux between the rotor 9b and the stator 9a is reduced, and the induced voltage is reduced.
[0055]
On the other hand, when the permanent magnet type electric motor 42 is used as a starter of the engine 2, a large current flows through the stator coils 9U, 9V, 9W, so that a magnetic attractive force acts between the stator 9a and the rotor 9b. . As a result, the stator 9a moves against the spring force of the coil spring 50 to the left in FIG. 6 and FIG. 7 (the direction facing the rotor 9b). As a result, the permanent magnet type motor 42 is in the state shown in FIG. 7, and the field magnetic flux between the rotor 9b and the stator 9a is increased, and the torque is increased.
[0056]
In the case of the fourth embodiment, when the permanent magnet type motor 42 is operated as a generator, the current flowing through the stator coils 9U, 9V, and 9W is the difference voltage between the induced voltage and the terminal voltage of the battery 10. The current flows up to a value divided by the internal resistance value of the permanent magnet type motor 42 and the battery 10. Therefore, for example, the permanent magnet type motor 42 may be configured so that this current value is smaller than the starting current flowing in the stator coils 9U, 9V, 9W when the permanent magnet type motor 42 is started using the starter.
[0057]
Further, as the current setting value of the drive circuit of the permanent magnet type electric motor 42, for example, the current setting value when operating as a generator may be controlled to be smaller than the current setting value when operating as a starter. .
[0058]
Further, for example, as a starter characteristic, in order to instantly start the engine 2, it is necessary to generate a large torque in the permanent magnet type motor 42. It is good also as a structure controlled to flow and generate | occur | produce a large torque.
[0059]
The configuration of the fourth embodiment other than that described above is the same as that of the first embodiment. Accordingly, in the fourth embodiment, substantially the same operational effects as in the first embodiment can be obtained. Further, in this fourth embodiment, when the stator coil current when operating as a generator is set smaller than the stator coil current when operating as an electric motor, the field magnetic flux is reliably set when operating as a generator. When the motor is operated as an electric motor, switching can be performed so as to increase the field magnetic flux.
[0060]
Further, in the fourth embodiment, as the rotor 9b of the permanent magnet type motor 42, the configuration in which the permanent magnet 9d is embedded in the rotor yoke 9c is used. However, the present invention is not limited to this. For example, as shown in FIG. A configuration in which a permanent magnet is embedded in a rotor yoke and a gap is provided may be used, or a configuration in which a permanent magnet is provided on the outer periphery of the rotor yoke as shown in FIG. 5 may be used.
[0061]
Furthermore, in the fourth embodiment, the stator 9a is moved by using the coil spring 50 and the magnetic attractive force. Instead, the stator is moved by an actuator such as an oil cylinder or an air cylinder. You may comprise as follows. Further, instead of configuring the stator 9b to be movable, the rotor may be configured to be movable, or both the stator and the stator may be configured to be movable.
[0062]
【The invention's effect】
As is apparent from the above description, the present invention provides a magnetic flux reduction means for reducing the field magnetic flux between the rotor and the stator when the permanent magnet type motor is operated as a generator in a predetermined rotational speed region. Therefore, it is possible to prevent the induced voltage from increasing when the motor is operated as a generator in a high-speed rotation region while the electric motor used as the engine starter is also used as the engine generator. Excellent effect.
[Brief description of the drawings]
FIG. 1 is an electrical configuration diagram showing a first embodiment of the present invention.
FIG. 2 is a sectional view of a permanent magnet type synchronous motor.
FIG. 3 is a diagram schematically showing the overall configuration of an automobile.
FIG. 4 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.
FIG. 5 is a view corresponding to FIG. 2 showing a third embodiment of the present invention.
FIG. 6 is a longitudinal side view of a permanent magnet type synchronous motor showing a fourth embodiment of the present invention.
FIG. 7 is a longitudinal side view of a permanent magnet type synchronous motor showing different states.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 is a motor vehicle, 2 is an engine, 9 is a permanent magnet type synchronous motor (alternator that also serves as a starter), 9a is a stator, 9b is a rotor, 9c is a rotor yoke, 9d is a permanent magnet, 9e is a rotating shaft, 10 is a battery, 11 Is a control device, 12 is an inverter circuit, 13U, 13V and 13W are transistors, 14U, 14V and 14W are transistors, 18 and 19 are input terminals, 20 and 21 are DC buses, 22U, 22V and 22W are output terminals, and 23 is Capacitor, 24 chopper circuit, 25 and 26 transistors, 27 and 28 diodes, 29 reactor, 30 battery voltage detector, 31 main circuit voltage detector, 32 position detector, 33 control circuit (magnetic flux) , 36 is a rotor, 37 is a rotor yoke, 38 is a permanent magnet, 39 is a rotor, 40 is a rotor yoke, 4 A permanent magnet, 42 is a permanent magnet type synchronous motor, 43 denotes a housing, the motor frame 44, the bearing bracket 45, 46, 47 bearing, 48 pin, 49 a bearing, 50 a coil spring.

Claims (2)

A rotor having a rotating shaft directly connected to or coupled to a drive shaft of an engine and having a permanent magnet, and a stator comprising a stator core and a stator coil wound around the stator core, and when starting the engine as an electric motor In an alternator that also functions as a starter composed of a permanent magnet type electric motor that operates as a generator after the engine has started,
A mechanism for changing the axial positional relationship between the rotor and the stator;
The mechanism has means for urging the rotor and the stator to be positioned at a position where the facing area of the rotor and the stator is reduced when not energized and when operated as the generator, When energized to operate as the electric motor, the rotor and the stator are positioned at a position where the opposing area of the rotor and the stator is substantially maximized by the magnetic attractive force between the rotor and the stator. alternator also serves as a starter, characterized in that it is configured. 2. The alternator also serving as a starter according to claim 1 , wherein the rotor is composed of a magnetic material and a permanent magnet embedded in the magnetic material .

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