JPH0638302A - Driver for electric automobile - Google Patents

Abstract

PURPOSE:To allow operation only through an induction motor with no trouble upon failure of inverter for synchronous motor and to allow charging of main battery without additionally requiring any special charging circuit. CONSTITUTION:The driver for electric automobile comprises a permanent magnet type synchronous motor 20 equipped with a permanent magnet rotor and an induction motor 30 constituted integrally, an AC motor 10 having wheel driving shaft coupled with a common rotor shaft of the motors 20, 30, inverters 25, 35 for feeding AC power individually to the windings of the motors 20, 30, a main battery 1 for feeding DC power to the inverters 25, 35, and means 27, 37 for disconnecting between the main battery 1 and the inverters 25, 35 electrically, as required. Furthermore, means 28 for disconnecting the synchronous motor 20 electrically is connected with AC output line of the inverter 25 for driving the synchronous motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for an electric vehicle which uses a main battery as a power source and drives an AC electric motor for driving wheels via an inverter.

[0002]

2. Description of the Related Art FIG. 3 shows a prior art of an electric vehicle drive device of this type. In the figure, 10 is an AC motor in which a permanent magnet type synchronous motor 20 having a permanent magnet in a rotor and an induction motor 30 are integrated in the same frame, and each of the motors 20 and 30 has the same rotor shaft. The rotor shaft is connected to the same shaft 11 to drive the wheel 4 which is a load. Further, the stator windings of the electric motors 20 and 30 are formed in a structure that does not magnetically interfere with each other.

Each of the electric motors 20 and 30 has at least two inverters 2 to which DC power is supplied from a common main battery 1.
5 and 35 respectively drive. Between the inverters 25 and 35 and the main battery 1, DC disconnecting means 27 and 37 such as a circuit breaker are connected so that they can be electrically disconnected from the main battery 1 as needed. . In the system in which the plurality of inverters 25 and 35 and the electric motors 20 and 30 are operated under the optimum load sharing, the efficiency is improved at the time of low output, the purpose is to disconnect the main battery 1 when one of the inverters fails, DC disconnection means 2
7,37 are used. In addition, each inverter 25, 35
2 between the DC disconnecting means 27 and 37
Reference numerals 6 and 36 function as filters for preventing the DC voltage from rising due to the harmonic currents flowing by the inverters 25 and 35.

[0004]

In the above prior art, for example, the inverter 2 for the permanent magnet type synchronous motor 20 is used.
In the case where 5 fails, assuming that the inverter 25 and the main battery 1 are disconnected by the DC disconnecting means 27 and only the induction motor 30 is operated by the other inverter 35, in the permanent magnet type synchronous motor 20, the rotation of the shaft 11 is prevented. Accordingly, the magnetic flux generated by the permanent magnet attached to the rotor traverses the stator windings to generate a speed electromotive voltage, which is applied to the defective inverter 25. This speed electromotive voltage acts to promote the failure depending on the failure content of the inverter 25, thus causing a serious problem. Further, conventionally, in an electric system as shown in FIG. 3, an effective means for charging the main battery 1 by using an inverter has not been provided, and a charging circuit added separately generally has a complicated circuit configuration and cost. It had the drawback of being too expensive.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a speed electromotive voltage to the inverter on the synchronous motor side even when only the induction motor is operated due to a failure of the inverter for the synchronous motor. It is an object of the present invention to provide a drive device for an electric vehicle that is capable of economically charging a main battery by adding a charging unit having a simple structure as necessary.

[0006]

In order to achieve the above object, the first aspect of the present invention is configured such that a permanent magnet type synchronous motor having a rotor having a permanent magnet and an induction motor are integrally formed. An AC motor in which a common rotor shaft of an electric motor is connected to a shaft for driving wheels, an inverter that individually supplies AC power to each winding of the synchronous motor and the induction motor, and a DC voltage is supplied to these inverters. In a drive device for an electric vehicle having a main battery that operates, and a DC disconnecting unit that disconnects electrical connection between the main battery and each inverter as necessary, an AC output line of the inverter that drives the synchronous motor is synchronized with the inverter. An electric motor disconnecting means for disconnecting electrical connection with the electric motor is provided.

A second invention is the same as the first invention,
An external AC power source is connected to the AC output side of the inverter electrically separated from the synchronous motor by the motor disconnecting means, and means for charging the main battery via the inverter is provided.

[0008]

In the first aspect of the invention, when the inverter for the permanent magnet type synchronous motor fails, the electric motor disconnecting means cuts off the electrical connection between the inverter and the synchronous motor, so that the speed electromotive voltage generated in the synchronous motor is generated. Acts so as not to join the inverter.

According to the second aspect of the present invention, an external AC power source is connected to the AC output side of the inverter in a state where the inverter is disconnected from the permanent magnet type synchronous motor by the motor disconnecting means. DC power is supplied to the main battery via the DC disconnecting means, and acts to charge the main battery.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the first invention. The same components as those in FIG. 3 are assigned the same reference numerals and detailed explanations thereof will be omitted. Hereinafter, different portions will be mainly described. That is, in this embodiment, a power line (inverter 2) that connects the permanent magnet type synchronous motor 20 and the inverter 25 that supplies AC power to the permanent magnet type synchronous motor 20.
A circuit breaker 28 is inserted in the AC output line 5) as a motor disconnecting means for disconnecting these electrical connections.

The operation will be described. If the inverter 25 for the synchronous motor 20 fails for some reason,
The inverter 25 is disconnected from the battery 1 by the DC disconnecting means 27 as in the conventional case. At this time, if the operation is continued by the sound inverter 35 and the induction motor 30, the permanent magnet type synchronous motor 20 will have the shaft 11
The magnetic flux of the permanent magnet attached to the rotor that rotates with the rotor crosses the stator windings to generate a speed electromotive force,
Since this is applied as a DC voltage to the inverter 25 via the freewheeling diode, the failure may be further promoted and further expanded depending on the content of the failure.

Therefore, in this embodiment, the breaker 28 shown in FIG. 1 is operated to disconnect the electrical connection between the synchronous motor 20 and the inverter 25, and then the induction motor 30 is operated. As a result, even if a speed electromotive voltage is generated in the permanent magnet type synchronous motor 20, this electromotive voltage will not adversely affect the inverter 25. When the inverter 35 for the induction motor fails, the induction current is not supplied to the induction motor 30, so that the speed electromotive voltage as described above does not occur and it is not necessary to interrupt the circuit.

FIG. 2 shows an embodiment of the second invention, in which the same components as those in FIG. 1 are designated by the same reference numerals.
In this embodiment, the motor disconnecting means for disconnecting the inverter 25 and the synchronous motor 20 is a changeover switch 29.
It is composed by. The switch 29 is for switching whether the AC output line of the inverter 25 is connected to the synchronous motor 20 or the AC power input terminal 40. In the changeover switch 29, the terminal b is the synchronous motor 20, and the terminal c is the reactor 41.
It is connected to the AC power supply input terminal 40 via. Here, although not shown, a single-phase or three-phase commercial power source is connected to the AC power source input terminal 40.

In this embodiment, the switch 29 is connected to the terminal b side, that is, the synchronous motor 20 side during normal operation, and the inverter 25 supplies AC power to the synchronous motor 20. Further, when a failure occurs in the inverter 25, the switch 29 is switched to the terminal a side, and the operation of the DC disconnecting means 27 causes the inverter 25 to be electrically connected to both the input and output sides (DC side and AC side). Separated from the circuit. Since this state is substantially the same as when the inverter 25 fails in the embodiment of FIG. 1, it is possible to prevent the speed electromotive voltage from being applied to the failed inverter 25 in the same manner as described above.

On the other hand, in a battery-equipped electric vehicle, as is well known, it is necessary to charge the main battery 1 after driving for a certain time or a certain distance. The embodiment shown in FIG. 2 is provided with this charging means, and the AC power supply input terminal 40 is of single-phase or three-phase type with the DC disconnecting means 27 closed and the switch 29 connected to the terminal a side. When commercial power is connected,
DC power can be supplied to the main battery 1 via the reactor 41, the switch 29, the return diode of the inverter 25, and the DC disconnecting means 27, whereby the main battery 1 is supplied.
Can be charged. Here, the reactor 41 is used for current limitation, and the insertion point may be between the AC power input terminal 40 and the commercial power supply.

According to this embodiment, the changeover switch 2
9 and the reactor 41, the AC power supply input terminal 40 and the like by simply adding a very simple configuration to the conventional main circuit
Charging circuit can be configured. Further, these charging circuit constituent elements can be mounted on a vehicle, and can contribute to downsizing and weight reduction of the vehicle. Further, there is an advantage that the utilization efficiency of the inverter 25 is improved by using the freewheeling diode during charging.

In each of the above embodiments, the case where one inverter is connected to each of the electric motors 20 and 30 has been described, but the present invention is also applicable to a system in which a plurality of inverters are connected in parallel.

[0018]

As described above, according to the first aspect of the present invention, when the inverter for the permanent magnet type synchronous motor fails, the electrical connection between the inverter and the synchronous motor is cut off so that when the inverter fails. It is possible to safely operate only the induction motor without promoting or expanding the failure of the inverter. Therefore, it is possible to significantly improve the redundancy of the electric vehicle or the entire drive system thereof.

According to the second aspect of the invention, by connecting the inverter to the external AC power source by using the motor disconnecting means, it is extremely economical, efficient, small and lightweight without adding a special charging circuit or the like. The charging means can be realized, and the added value of the drive device can be dramatically increased.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a first invention.

FIG. 2 is a circuit configuration diagram showing an embodiment of a second invention.

FIG. 3 is a circuit configuration diagram showing a conventional technique.

[Explanation of symbols]

 1 Main Battery 4 Wheels 10 AC Motor 11 Shaft 20 Permanent Magnet Synchronous Motor 25, 35 Inverter 26, 36 Capacitor 27, 37 DC Disconnecting Means 28 Breaker 29 Changeover Switch 30 Induction Motor 40 AC Power Input Terminal 41 Reactor a, b Terminal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hajime Motoyoshi 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Yoshio Ito 1 Nitta Tanabe, Kawasaki-ku, Kawasaki, Kanagawa No. 1 inside Fuji Electric Co., Ltd.

Claims (2)

[Claims] 1. A permanent magnet type synchronous motor having a rotor having a permanent magnet and an induction motor are integrally formed,
An AC motor in which a common rotor shaft of these motors is connected to a shaft for driving wheels, an inverter that individually supplies AC power to each winding of the synchronous motor and the induction motor, and a DC voltage to these inverters In a drive device for an electric vehicle having a main battery for supplying, and a DC disconnecting means for disconnecting the electrical connection between the main battery and each inverter as necessary, in an AC output line of an inverter for driving the synchronous motor,
A drive device for an electric vehicle, comprising an electric motor disconnecting means for disconnecting electrical connection between an inverter and a synchronous motor. 2. The drive device for an electric vehicle according to claim 1, wherein an external AC power supply is connected to an AC output side of the inverter electrically separated from the synchronous motor by the motor disconnecting means, and the main AC power is supplied via the inverter. A drive device for an electric vehicle, comprising a means for charging a battery.