JPH066907A - Superconducting motor unit in electric automobile - Google Patents

Abstract

PURPOSE:To obtain a superconducting motor unit comprising a superconducting motor as a power supply for an electric automobile in which power can be regenerated from the superconducting motor upon braking of the electric automobile. CONSTITUTION:First and second armature coils 11, 12 are disposed on the rotor side of a motor, i.e., a power source for an electric automobile. A field coil 13 comprises a superconductor and disposed on the stator side of the motor. Switches 15-21 and a switch unit 22 are provided for forming a driving current path, a regenerating current path, and the like. When the electric automobile is driven, driving current paths are established from a battery 14 to the field coil 13 and the armature coils 11, 12 and the motor is rotated. When the electric automobile is braked, regenerating current paths are established from the armature coils 11, 12 to the field coil 13 and power is regenerated to be stored in the field coil 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting motor device which utilizes a superconducting motor as a power source for an electric vehicle and drives the electric vehicle and regenerates electric power during braking.

[0002]

2. Description of the Related Art In recent years, the development of electric vehicles has progressed, and one of the development themes is how to use electric power efficiently.

Therefore, when the vehicle is running, it is devised to collect electric power from various places as much as possible and return the electric power to the secondary battery. For example, a solar cell is attached to collect the electric power generated here, or when decelerating the vehicle, the motor that is the power source is regarded as a generator and the electric power regenerated from this motor is collected ( 1991/11
It is described in Nikkei Electronics, published on March 11, entitled "Development of Electric Vehicles Accelerates, From Experiment to Practical Age".

[0004]

By the way, a motor using a superconductor for a winding is remarkable because of its low loss, and is also highly useful as a power source for an electric vehicle. Further, as described above, by using the motor as a generator together with the recovery of electric power, the utilization efficiency of electric power can be improved as never before.

Therefore, an object of the present invention is to apply a superconducting motor as a power source for an electric vehicle and obtain a superconducting motor device for regenerating electric power from the superconducting motor when the electric vehicle is being braked.

[0006]

In order to solve the above problems, the present invention has a plurality of armature coils and a field coil using a superconductor as a wire rod, and drives a wheel of an electric vehicle. A motor, a power supply for the motor,
Switch means for forming a driving current path for guiding a current from the power source to each armature coil and field coil of the motor, and a regeneration current path for guiding a current from each armature coil to the field coil The switch means forms the drive current path when the electric vehicle is driven, and forms the regeneration current path when the electric vehicle is braked.

[0007]

According to the present invention, the driving current path is formed when the electric vehicle is driven. This drive current path guides a current from the power supply to each armature coil and field coil of the motor, whereby the motor rotates. Further, when the electric vehicle is braked, a regenerative current path is formed. The current path for regeneration is a path for guiding a current from each armature coil of the motor to the field coil, and since the field coil is a superconductor, the current is accumulated here. That is,
During braking of an electric vehicle, the motor is regarded as a generator, and the current generated in each armature coil is guided to the field coil through the regenerative current path and accumulated in this field coil.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the structure of an embodiment of the super-electric motor device according to the present invention, and FIG. 2 shows the sectional structure of the motor in the device of this embodiment.

The motor 1 in the apparatus of this embodiment is directly connected to the shaft of the wheel of an electric vehicle and is used as a power source for this electric vehicle. This motor 1 is
The armature coil 11 and the second armature coil 12 are provided on the rotor side, and the field coil 13 is provided on the stator side. The field coil 13 is supplied with a direct current and forms a magnetic field in its inner space. Each of the armature coils 11 and 12 is supplied with an alternating current and rotates the rotor due to the interaction with the magnetic field by the field coil 13.

The DC power supply 14 is a fuel cell that uses liquid hydrogen as a fuel, and supplies a current to each of the armature coils 11 and 12 and the field coil 13.

The switches 15 to 21 and the switching elements incorporated in the switch unit 22 are turned on and off at their respective timings, as will be described later. As a result, the DC power supply 14 is connected to each armature coil 1
1, 12 and a field current for driving to the field coil 13 are formed, and a current path for regeneration from each armature coil 11, 12 to the field coil 13 is formed.

The switch unit 22 includes the first to eighth thyristors 31 to 38 and the first to eighth diodes 41.
˜48 and four capacitors 51 to 54, and the thyristors 31 to 38, which are switching elements, are turned on and off at their respective timings.

The field coil 23 is formed by winding a wire of a superconductor. This superconductor field coil 13
Is located in a closed space between the inner sleeve 55 of the motor and the outer shield 56, and is cooled by a cooling medium circulating in the closed space. The cooling medium is liquid hydrogen, and liquid hydrogen that is a fuel for the DC power supply 14 is used.
Since the fuel of the DC power supply 14 is used to cool the field coil 13, a cooling medium for cooling the field coil 13 is not particularly required, and the device can be downsized. That is, when a superconductor is used, its cooling mechanism tends to be relatively large, but by using the fuel of the DC power supply 14 as a cooling medium for the superconductor,
This prevents the cooling mechanism from becoming large. Moreover, it is also advantageous in terms of cost reduction.

Here, the superconductor used for the field coil 13 is preferably, for example, an oxide superconductor, and more specifically, an HTc material is preferable. This is because the HTc material exhibits superconducting properties even at a liquid nitrogen temperature of 77 (K), but at a liquid hydrogen temperature of 20 (K), it is about 10 times as large as at a liquid nitrogen temperature. This is because it can pass an electric current.
In this case, as will be described later, when the motor current is collected and stored in the field coil 13, a larger amount of current can be stored in the field coil 13.

The armature coils 11 and 12 are each formed by winding an ordinary conductor wire, and for example, a Cu wire is used.

When the electric vehicle is driven, a driving current path from the DC power supply 14 to the field coil 13 and the armature coils 11 and 12 as described below is formed.

First, as shown in FIG. 1, each switch 15,
16 is turned on, and the current Ib flows through the path of the DC power supply 14 → switch 15 → switch 16 → field coil 13. As a result, the field coil 13 is excited and a magnetic field is generated.

At the same time, the switches 18 and 21 are turned on, and the DC power supply 14 → switch 18 → switch unit 22 → first armature coil 11 → switch unit 22 → second armature coil 12 → switch unit. 32
→ The current Ia flows through the path of the switch 31. At this time, the first to eighth thyristors 31 to 38 in the switch unit 22 are (b-1) to (b-8) in FIG.
It is turned on and off at the respective timings shown in
Along with this, the first and second armature coils 11 and 12
, Currents Ia1 and Ia2 of respective phases shown in (a-1) and (a-2) of FIG. 3 flow.

Here, the first and third thyristors 31 and 33 in the switch unit 22 are shown in FIG.
1) and (b-3), they are turned on at the same timing. At this time, the first thyristor 31
-> 1st diode 41-> 1st armature 11-> 3rd diode 43-> The electric current Ia1 flows through the path | route of the 3rd thyristor 33.

The second and fourth thyristors 32,
34 is turned on at the same timing as shown in (b-2) and (b-4) of FIG. 3, and is turned on later than the first and third thyristors 31 and 33 by 180 degrees. At this time, the second thyristor 32 → the second diode 42 → the first armature 11 → the fourth diode 4
The current Ia1 flows through the path of 4 → fourth thyristor 34, and the current Ia1 flows in the direction opposite to that when the first and third thyristors 31 and 33 are on.

On the other hand, the sixth and eighth thyristors 36,
38 is turned on at the same timing as shown in (b-6) and (b-8) of FIG. 3, and is turned on 90 degrees later than the first and third thyristors 31 and 33. At this time, the sixth thyristor 36 → the sixth diode 46 → the second armature 12 → the eighth diode 48.
→ The current Ia2 flows through the path of the eighth thyristor 38.

Further, the fifth and seventh thyristors 3
5, 37 are turned on at the same timing as shown in (b-5) and (b-7) of FIG.
The thyristors 36, 38 are turned on after being delayed by 180 degrees. At this time, the fifth thyristor 35 → the fifth
The current Ia2 flows through the path of the diode 45 → the second armature 12 → the seventh diode 47 → the seventh thyristor 37.

As described above, the first to eighth thyristors 31
By turning on and off at each timing, the current Ia1 flows through the first armature coil 11,
The second armature coil 12 has a phase of 90 from the current Ia1.
A current Ia2 delayed by a degree flows. As a result, the motor 1 rotates, the wheels of the electric vehicle rotate, and the electric vehicle is driven.

Next, when shifting from driving of the electric vehicle to braking, instead of the driving current path shown in FIG. 1, the armature coils 11 and 12 as shown in FIG.
A regenerative current path to 3 is immediately formed. The time when the electric vehicle shifts to braking may be, for example, when decelerating the electric vehicle or when starting the constant speed running on a downhill.

As shown in FIG. 4, the switch 15 is turned off and the DC power supply 14 is disconnected. Also, the switches 18 and 21 are turned off, and the switches 19 and 20 are turned on instead. Further, the first to the eighth thyristors 31 to 38 in the switch unit 22.
Is turned on and off at the respective timings shown in (b-1) to (b-8) of FIG. 3, as in the case of driving described above. However, during braking, the rotation angle of the rotation shaft of the motor 1 is detected by an encoder (not shown), and the thyristors 31 to 38 are turned on and off at respective timings corresponding to the detected rotation angle. To

Here, when shifting from driving the electric vehicle to braking, the switch 15 is turned off and the DC power source 14 is turned on.
However, the magnetic field generated by the field coil 13 is
It does not disappear immediately and remains for a while.

Therefore, at the start of braking of the electric vehicle,
The armature coils 11 and 12 rotate in the residual magnetic field of the field coil 13 and generate respective currents. That is, the motor 1 operates as a generator, and each armature coil 1
The respective currents flow in 1 and 12. At this time, the first to eighth thyristors 31 in the switch unit 22
3 to 38 are turned on and off at the respective timings shown in (b-1) to (b-8) of FIG. 3, so that the armature coils 11 and 12 have (a-1) shown in FIG. And currents Ia1 and Ia2 shown in (a-2) respectively flow.
Accordingly, each current Ia is output from the switch unit 22.
A current Ic, which is the sum of 1 and Ia2, is output, and this current Ic
Is switch unit 22 → switch 20 → switch 1
It flows in the route of 6 → field coil 13 → switch 19. As a result, not only the magnetic field of the field coil 13 gradually becomes stronger, but also the current flowing through the field coil 13 gradually increases. That is, electric power is regenerated and is collected as a current flowing through the field coil 13.

Next, when the braking of the electric vehicle shifts to the stop, the current path for storage shown in FIG. 5 is immediately formed in place of the current path for regeneration shown in FIG.

Here, only the switch 17 connected in parallel to the field coil 13 is turned on and the other switches 15, 16, 18, 19, 20, 21 are turned off. At this time, a closed loop is formed by the field coil 13 and the switch 17, and since the field coil 13 is a superconductor, the current Id continues to flow and is accumulated in this closed loop. This current Id is obtained from the current flowing through the field coil 13 when the above-described regeneration current path is formed.

After that, when the electric vehicle is driven again, the current Id flowing in the field coil 13 may be used. At this time, the current path shown in FIG. The eighth thyristors 31 to 38 are turned on and off at the respective timings shown in (b-1) to (b-8) of FIG. As a result, the current Id accumulated in the field coil 13 is converted into the switch 19 → the switch unit 22 → the first armature 11
→ Switch unit 22 → Second armature 12 → Switch unit 22 → Switch 20 → Switch 16 As a result, the motor 1 rotates and the electric vehicle is driven. That is, although the switch 15 is opened and no current is supplied from the DC power supply 14, the motor 1 is driven only by the current accumulated in the field coil 13.
Rotates.

When the electric vehicle does not stop and directly shifts from braking to re-driving, it is not necessary to form the storage current path shown in FIG. 5, and only the regeneration current path shown in FIG. Move on to re-driving. In this case, current continues to flow through the same current path from braking to re-driving.

By the way, in the apparatus of the above embodiment, the motor 1 has dimensions of 300 (mm) in diameter and 600 (m) in length.
m) and the weight is 150 (Kg). The output of the motor 1 is 50 (KW) and the dipole magnetic field strength is 4
(T). Further, the field coil 13 which is a superconductor
The stored energy capacity of is 300 (KJ).

When such a motor 1 is directly connected to the axle of an electric vehicle having a weight of 1 (t), the motor 1 rotates at a speed of 1000.
By rotating at (rpm)
The vehicle can be driven at (Km / h), and the kinetic energy at that time is 250 (KJ). Until the electric vehicle is stopped, if the regenerative current path shown in FIG. 4 is formed, 20 to 20 of the kinetic energy 250 (KJ)
30 (%) can be collected in the field coil 13.

As described above, in the above embodiment, since the superconducting motor is used as a power source and the electric power regenerated from this motor is collected in the field coil of the motor, the utilization efficiency of the electric power should be extremely high. You can

Further, since liquid hydrogen, which is a fuel for the DC power supply, is used to cool the field coil, which is a superconductor, the cooling mechanism for this field coil can be miniaturized. Further, since this field coil is used not only as the coil of the motor but also for storing the regenerated electric power, it is not necessary to provide a special means for storing the regenerated electric power. In this way, the cooling mechanism of the field coil is downsized, and the field coil is also used for storing electric power, so that an extremely compact device as a whole can be obtained.

[0037]

As described above, according to the present invention, a motor whose field coil is a superconductor is used as a power source for an electric vehicle, and when the electric vehicle is being braked, the motor is regarded as a generator and each armature. Since the current generated in the coil is led to the field coil and stored, the efficiency of use of electric power can be improved. Further, since the field coil is also used for storing electric power, a compact device can be realized.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an embodiment of a super electric motor device according to the present invention.

FIG. 2 is a diagram showing a sectional structure of a motor in the apparatus of this embodiment.

FIG. 3 is a timing chart used to explain the operation of the circuit shown in FIG.

FIG. 4 is a diagram showing a state in which a regenerative current path is formed in the circuit shown in FIG.

5 is a diagram showing a state in which a storage current path is formed in the circuit shown in FIG.

[Explanation of symbols]

 1 Motor 11 1st armature coil 12 2nd armature coil 13 Field coil 14 DC power supply 15-21 switch 22 Switch unit

Claims (2)

[Claims] 1. A motor having a plurality of armature coils and a field coil using a superconductor as a wire rod for driving a wheel of an electric vehicle, a power supply for the motor, and each electric machine from the power supply to the motor. A drive current path that guides a current to the child coil and the field coil; and a switch means that forms a regenerative current path that guides a current from each of the armature coils to the field coil. A superconducting motor device for an electric vehicle, wherein the driving current path is formed when the electric vehicle is driven, and the regeneration current path is formed when the electric vehicle is braked. 2. The superconducting motor device in an electric vehicle according to claim 1, wherein the power source is a fuel cell using liquid hydrogen as a fuel, and a field coil of the motor is cooled by the liquid hydrogen.