JPH0965577A - Electric vehicle battery charger - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To reduce the weight of a vehicle body of an electric vehicle, to extend the mileage, and to improve the acceleration performance. A first winding (3) of a high frequency isolation transformer (30)
0a is applied with the high-frequency power supply voltage obtained by the high-frequency inverter circuit 29, and the high-frequency voltage induced in the second winding 30b of the high-frequency insulation transformer 30 is applied to the flywheel diodes 30e to 30h of the high-frequency inverter circuit 31.
Then, the battery 13 is charged with the obtained DC voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charger for an electric vehicle that charges a battery for supplying power to a motor for traveling.

[0002]

2. Description of the Related Art In an electric vehicle, DC power from a battery is converted into AC power by an inverter circuit, which is a drive circuit, and is supplied to a running motor, for example, an induction motor. In this case, when the battery discharges and the voltage drops, the electric power required to drive the induction motor cannot be obtained, so the battery needs to be charged by an external power source.

[0003]

Therefore, in the conventional art,
As shown in FIG. 6, for example, the voltage of the commercial power supply 1 having a single phase of 200 V is boosted by the commercial power supply transformer 2 and rectified by the rectifying circuit 3, and the battery 4 of, for example, 330 V is supplied.
Although the battery charging device 5 for charging the vehicle is provided, the commercial power supply transformer 2 has a large weight, which increases the weight of the vehicle body of the electric vehicle and shortens the traveling distance per charge of the battery 4. Moreover, there is a problem that the acceleration performance is deteriorated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a battery charging device for an electric vehicle, which can be made compact and lightweight by using a high frequency insulating transformer.

[0005]

According to a first aspect of the present invention, there is provided a battery charger for an electric vehicle in which an electric vehicle is driven by a drive circuit based on DC power from a battery. To a high frequency power supply, a high frequency power supply generating means for converting the high frequency power supply to a high frequency power supply, a high frequency power insulating transformer having a high frequency power supply from the high frequency power generating means as a primary side input, and a rectifier for charging the battery by rectifying a secondary side output of the high frequency power insulating transformer It is characterized by the configuration including means.

According to a second aspect of the present invention, there is provided a battery charging device for an electric vehicle, wherein the high frequency insulating transformer includes first to third windings, and the rectifying means converts the DC power source of the battery into a high frequency power source. When the battery is charged, the first winding functions as a primary side to which the high frequency power source from the high frequency power source generating means is input, and the second winding functions as a secondary side. The second winding functions as a primary side for inputting the high frequency power from the rectifying means, and the third winding functions as a secondary side for inputting the high frequency power to the auxiliary charging means for floating charging the auxiliary battery. It is characterized by its structure.

A battery charging device for an electric vehicle according to a third aspect is characterized in that the third winding of the high frequency insulating transformer functions as a secondary side even when the battery is being charged.

A battery charging device for an electric vehicle according to a fourth aspect is characterized in that the auxiliary battery drives a battery cooling fan for cooling the battery.

The battery charging device for an electric vehicle according to a fifth aspect of the invention is, in addition to the battery charging means for the auxiliary device, an auxiliary battery for converting the DC power source of the battery into a high frequency power source and stepping down and rectifying the high frequency power source to charge the auxiliary battery. It is characterized in that it is provided with a charging means dedicated to the battery for the battery.

In the battery charging device for an electric vehicle according to the sixth aspect, one of the auxiliary battery charging means and the auxiliary battery dedicated charging means operates normally, and when the auxiliary battery has insufficient discharge capacity. It is characterized in that the other is configured to operate.

A battery charging device for an electric vehicle according to a seventh aspect is characterized in that the output side of the rectifying means is connected to a part of the drive circuit to control the charging current of the battery. Have.

A battery charging device for an electric vehicle according to an eighth aspect is characterized in that the charging current of the battery is power factor controlled.

A battery charging device for an electric vehicle according to a ninth aspect of the present invention is characterized in that a part of the drive circuit constitutes a step-up chopper circuit using a stator coil of the motor.

A battery charging device for an electric vehicle according to a tenth aspect is characterized in that a step-up / step-down chopper circuit is connected between the battery and the drive circuit.

The battery charging device for an electric vehicle according to an eleventh aspect is characterized in that the charging current of the battery is controlled by the step-down action of the step-up / step-down chopper circuit when the voltage of the battery drops.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1 showing the overall configuration, an electric motor is equipped with an induction motor 11 as a motor for traveling.
A stator 12 having a plurality of phases, for example, three phases of stator coils 12U, 12V and 12W, and a rotor (not shown) are provided. Further, the electric vehicle is equipped with a rechargeable battery 13 made of a nickel-based battery, and the DC power from the battery 13 is converted into AC power by an inverter circuit 14 as a drive circuit to be supplied to the induction motor 11. It is being supplied.

The inverter circuit 14 includes NPN type transistors 15U, 15V, 1 which are six switching elements.
5W and 16U, 16V, 16W are constructed by connecting three-phase bridges, and flywheel diodes 17U, 17V, 17W are provided between the collector and emitter of each.
And 18U, 18V, 18W are connected, thus having three arms 19U, 19V and 19W. The input terminals 20 and 21 of the inverter circuit 14 are connected to the DC buses 23 and 24 to which the capacitors 22 are connected between the lines, and the output terminals 25U, 25V and 25W are the stator coils 12U and 12V of the induction motor 11. , And 12 W each. The stator coils 12U, 12V and 12 of the induction motor 11 are
The other terminals of W are commonly connected.

The high frequency isolated power supply circuit 26 is used for the battery 13
This is for charging the battery and will be described below.
That is, the full-wave rectifier circuit 27, which is formed by bridge-connecting four diodes 27a to 27d, has its AC input terminal connected to an external power source, for example, a single-phase 200-volt commercial power source 28 via AC power source lines 52 and 53. Thus, the single-phase AC power supply voltage of 200 V is full-wave rectified. High-frequency inverter circuit 29 as high-frequency power generation means
Is configured by bridge-connecting four NPN-type transistors 29a to 29d, the DC input terminal of which is connected to the DC output terminal of the full-wave rectifier circuit 29 and the AC output terminals of the first to It is connected to both terminals of the first winding 30a of the high-frequency insulation transformer 30 having the third windings 30a to 30c. In this case, flywheel diodes 29e to 2 are provided between the collectors and emitters of the transistors 29a to 29d of the high frequency inverter circuit 29.
9h are connected respectively.

Second winding 30 of high frequency isolation transformer 30
Both terminals of b are connected to the AC side terminals of a high frequency inverter circuit 31 formed by bridge-connecting four NPN type transistors 31a to 31d. Flywheel diodes 31e to 31h, which also function as rectifying means, are connected between the collectors and emitters of the transistors 31a to 31d of the high frequency inverter circuit 31, respectively, and the DC side terminal of the high frequency inverter circuit 31 is
It is connected to the DC input terminals 20 and 21 of the inverter circuit 14.

Third winding 30 of high frequency isolation transformer 30
Both terminals of c are connected to an AC input terminal of a full-wave rectifier circuit 32 which is a battery charging means for an auxiliary device, which is a bridge connection of four transistors 32a to 32d, and a DC output terminal of the full-wave rectifier circuit 32 is It is connected to both terminals of the auxiliary battery 33. The turn ratio of the first to third windings 30a to 30c in the high frequency isolation transformer 30 is
It is set as described later.

Thus, an input terminal of a drive motor 34a of a battery cooling fan 34, which is an auxiliary device for cooling the battery 13, is connected to both terminals of the auxiliary device battery 33, and a headlight as an auxiliary device, Other lighting equipment, instruments, etc. are connected.

The dedicated charging circuit 35, which is a dedicated charging means for the auxiliary battery, includes a high frequency inverter circuit 36, a high frequency insulating transformer 37 and a full wave rectification circuit 38. The high frequency inverter circuit 36 is configured by connecting four NPN transistors 36a to 36d (flywheel diodes 36e to 36h are connected between collectors and emitters) in a bridge connection, and its DC input The terminals are connected to both terminals of the battery 13, and the AC output terminals are connected to both terminals of the primary winding 37 a of the high frequency insulation transformer 37. This high frequency insulation transformer 37
The winding ratio of the primary winding 37a and the secondary winding 37b is set so as to reduce the voltage.

The full-wave rectifier circuit 38 includes four diodes 3
8a to 38d are bridge-connected,
The AC input terminal is connected to both terminals of the secondary winding 37b of the high frequency insulation transformer 37, and the DC output terminal is connected to both terminals of the auxiliary battery 33.

Charging current detector 39 as a DC current detecting means
Is arranged on the DC bus 23 and detects the charging current Id flowing through the battery 13. The auxiliary battery voltage detector 40, which is a DC voltage detecting means, is connected between both terminals of the auxiliary battery 33 to detect the inter-terminal voltage Vadc of the auxiliary battery 33.

The control circuit 41 serving as a control means is mainly composed of a microcomputer. Each input port is connected with each output terminal of the charging current detector 39 and the auxiliary battery voltage detector 40. The output ports of the group are transistors 15U to 15W of the inverter circuit 14.
, And 16 U to 16 W of each base (gate), and the other group of output ports is connected to the high frequency inverter circuit 29.
Bases (gates) of the transistors 29a to 29d of
Is connected to the bases (gates) of the transistors 31a to 31d of the high-frequency inverter circuit 31, and the output port of the other group is connected to the transistors 36a to 36d of the high-frequency inverter circuit 36.
Is connected to each base (gate).

The high frequency isolated power circuit 26, the dedicated charging circuit 35 and the control circuit 41 constitute a battery charging device.

Next, the operation of this embodiment will be described with reference to FIGS. 2 and 3. (1) Driving of Induction Motor 11 First, the operation of the electric vehicle during traveling will be described. That is, the control circuit 41 includes the transistor 15U of the inverter circuit 14.
To 15W and 16U to 16W, energization timing signals are generated, and base signals (gate signals) S1 are given to the transistors 15U to 15W and 16U to 16W in a predetermined order in accordance with the energization timing signals, and the transistors 15U to 15W are supplied. And 16U to 16W are turned on / off. As a result, the inverter circuit 14
Generates an AC voltage from the DC voltage of the battery 13 and supplies the AC voltage to the induction motor 11, the induction motor 11 rotates, and the electric vehicle runs.

In this case, the control circuit 41 changes the voltage applied to the stator coils 12U to 12W of the induction motor 11 by PWM-controlling the transistors 15U to 15W of the inverter circuit 14, thereby rotating the induction motor 11. By controlling the speed, the traveling speed of the electric vehicle is changed.

(2) Charging of the battery 13 When the battery 13 is discharged and the voltage drops, the electric power required to drive the induction motor 11 cannot be obtained. In this case, therefore, the battery 13 has an external AC power source. Charge from. That is, when the commercial power supply 28 is connected to the high frequency isolated power supply circuit 26, the control circuit 41 automatically switches to the charging mode, and in this charging mode, the high frequency inverter circuit 29 is used.

That is, the control circuit 41 includes transistors 29a, 29d and 29b, 2 of the high frequency inverter circuit 29.
The gate signal S2 is alternately applied to 9c to turn it on and off, and thus a high frequency power supply voltage of, for example, 200 KHz is applied to the first winding 30a of the high frequency isolation transformer 30. As a result, a slightly boosted high-frequency voltage is induced in the second winding 30b of the high-frequency insulation transformer 30, and this is full-wave rectified by the full-wave rectifier circuit including the flywheel diodes 31e to 31h of the high-frequency inverter circuit 31. For example, the inverter circuit 1 as a DC voltage of about 360 V
It is applied between the four input terminals 20 and 21.

Therefore, the charging current Id flows through the battery 13. As is apparent from this, when the battery 13 is charged, the first winding 30 of the high frequency isolation transformer 30 is
a functions as a primary winding, and the second winding 30b functions as a secondary winding.

On the other hand, when the charging current Id flows through the battery 13, the charging current Id is detected by the charging current detector 39, and the detected charging current Id is given to the control circuit 41. Then, the control circuit 41 sets the transistors 29a, 29d and 29b, 29c of the high frequency inverter circuit 29 so that the charging current Id becomes a preset set value.
Controls the on-off duty ratio of. Therefore, the battery 13 is stably charged.

(3) Floating Charge of Auxiliary Battery 33 During charging of the battery 13, a reduced high frequency voltage is also induced in the third winding 30c of the high frequency insulation transformer 30, and the full wave is rectified by the full wave rectifier circuit 32. It is rectified into a direct current voltage of, for example, 12 volts, and the auxiliary battery 33 is loosely charged by this direct current voltage. The auxiliary DC power source from the auxiliary battery 33 is a battery cooling fan 34.
Of the battery cooling fan 3 supplied to the drive motor 34a of
4 is driven to cool the battery 13 and the auxiliary battery 33.

Further, when the induction motor 11 is driven (when the electric vehicle is running), the control circuit 41
Transistors 31a and 31 of the high frequency inverter circuit 31
The gate signal S3 is alternately applied to b and 31b, 31c to turn them on and off, and thus the high frequency power supply voltage is applied to the second winding 30b of the high frequency isolation transformer 30. This allows
A reduced high-frequency voltage is induced in the third winding 30c of the high-frequency insulation transformer 30, and this is full-wave rectified by the full-wave rectifier circuit 32 to become a DC voltage, and this DC voltage idle-charges the auxiliary battery 33. It That is, when the induction motor 11 is driven, the second winding 30b of the high frequency insulation transformer 30 functions as a primary winding and the third winding 30c functions as a secondary winding.

Terminal-to-terminal voltage Vadc of the auxiliary battery 33
Is detected by the auxiliary battery voltage detector 40, and the detected inter-terminal voltage Vadc is given to the control circuit 41. The control circuit 41 compares the inter-terminal voltage Vadc with a set value (for example, 12 volts) and controls the on / off duty ratio of the transistors 31a to 31d of the high frequency inverter circuit 31.

FIG. 2 shows a circuit extracted when the auxiliary battery 33 is charged by using the high frequency inverter circuit 31. The control circuit 41 controls the inter-terminal voltage V
When adc is smaller (lower) than the set value, as shown in FIG. 3A, the transistors 31a, 31d and 31b,
31c gate signals S3a, S3d and S3b, S3c
The ON / OFF duty ratio of is set to a large value and the inter-terminal voltage Va
When dc is substantially equal to the set value (middle), as shown in FIG. 3B, gate signals S3a, S3d and S3b, S are generated.
The on / off duty ratio of 3c is set smaller than that in the case of FIG. 3A, and the inter-terminal voltage Vadc is larger (higher) than the set value.
In this case, as shown in FIG. 3C, the gate signal S3
The duty ratios of a, S3d and S3b, S3c are shown in FIG.
It is set smaller than in the case of (b), and the inter-terminal voltage Va
The dc is controlled so as to be a substantially set value.

The control circuit 41 then controls the gate signal S3.
Even if the on / off duty of a, S3d and S3b, S3c is increased as shown in FIG. 3 (a), if the inter-terminal voltage Vadc is below the set value, that is, at night, etc. When the light and other devices are connected and the discharge capacity is insufficient, the transistors 36a, 36 of the high frequency inverter circuit 36 of the dedicated charging circuit 35
The gate signal S4 is alternately applied to d and 36b and 36c to turn them on and off. As a result, the high frequency isolation transformer 37
A high-frequency voltage is applied to the primary winding 37a, and a reduced high-frequency voltage is induced in the secondary winding 37b, which is full-wave rectified by a full-wave rectifying circuit 38 and converted into a DC voltage. The battery 33 for auxiliary devices is loosely charged by the voltage. The high frequency inverter circuit 33 is also controlled similarly to the high frequency inverter circuit 31. Therefore, the auxiliary battery 33 is charged by the operations of both the high frequency inverter circuits 31 and 36.

As described above, according to this embodiment, since the high frequency insulated power supply circuit 26 obtains the DC voltage for charging the battery 13 from the commercial power supply 28 which is the external power supply,
A high frequency isolation transformer 30 can be used in place of the conventional commercial power transformer 2, and since the high frequency power transformer 30 is smaller and lighter than the commercial power transformer 2, the vehicle-mounted space can be reduced accordingly. At the same time, the weight of the vehicle body can be reduced, the traveling distance per charge of the battery 13 can be increased, and
Acceleration performance can also be improved.

Incidentally, the conventional commercial power supply transformer 2 has a capacity of, for example, 5 KVA and has a weight of about 40 to 45 kg, but the high frequency insulating transformer 30 for transforming the high frequency power supply of 200 KHz of this embodiment is used. Since the iron core cross-sectional area is inversely proportional to the frequency, the weight can be reduced to about 1/4 of the conventional weight.

Further, according to the present embodiment, the high frequency insulating transformer 33 has the first winding 30a which functions as a primary winding and the second winding which functions as a secondary winding when the battery 13 is charged.
In addition to the winding 30b, a third winding 30c is provided, and when the battery 13 is charged, a reduced high frequency voltage is induced in the third winding 30c. Since the battery 33 is float-charged,
Floating charging of the auxiliary battery 33 can be performed together with charging of the battery 13. Therefore, when the battery 13 is charged, the battery cooling fan 34 can be driven using the auxiliary battery 33, and the battery 13 and the auxiliary battery can be driven. 33 can be cooled effectively.

Further, according to this embodiment, the high frequency inverter circuit 31 which also functions as a full-wave rectifier circuit is provided between the second winding 30b of the high frequency isolation transformer 30 and the input terminals 20 and 21 of the inverter circuit 14. When the induction motor 11 is driven (when the electric vehicle is running), the high frequency power source voltage is obtained from the direct current power source voltage from the battery 13 by the high frequency inverter circuit 31, and this high frequency power source voltage is supplied to the high frequency insulating transformer 30. By applying the voltage to the second winding 30b, a reduced high-frequency voltage is induced in the third winding 30c, and thereby the auxiliary battery 33 is floatingly charged via the full-wave rectifier circuit 32. And
Separately from this, a dedicated charging circuit 35 for exclusively charging the auxiliary battery 33 is provided (this circuit is also provided in the related art), and the floating battery 33 for auxiliary operation by the operation of the high frequency inverter circuit 31 also causes the charging. When the discharge capacity of the auxiliary battery 33 is insufficient, the dedicated charging circuit 35 is additionally operated to floating-charge the auxiliary battery 33.

Therefore, even when the auxiliary device (load) connected to the auxiliary battery 33 is different in the daytime, nighttime, etc.,
The auxiliary battery 33 can be efficiently floating-charged, and the power consumption for the floating charging of the auxiliary battery 33 by the battery 13 can be optimized.

The following may be considered as modifications of the first embodiment. For example, the output capacity for charging the auxiliary battery 33 obtained by the operation of the high frequency inverter circuit 31 is set to 500 watts, the output capacity obtained by the dedicated charging circuit 35 is set to 250 watts, and the dedicated charging is always performed. The circuit 35 is operated to float-charge the auxiliary battery 33.
If the discharge capacity of the auxiliary battery 33 becomes insufficient, the high-frequency inverter circuit 31 is switched to operate, and if the discharge capacity of the auxiliary battery 33 becomes insufficient, the high-frequency inverter circuit 31 and the dedicated Charging circuit 3
Both 5 are operated.

With such a structure, the floating charge of the auxiliary battery 33 is carried out in three stages, so that the floating charge of the auxiliary battery 33 can be carried out more efficiently.

FIGS. 4 and 5 show a second embodiment of the present invention, in which the same parts as those in FIG. 1 are designated by the same reference numerals.
The different parts will be described.

In FIG. 4, the buck-boost chopper circuit 42
Is a transistor module having NPN type transistors 43 and 44 as switching elements and flywheel diodes 45 and 46,
In the transistor 43, the collector is the DC bus 2
3, the emitter is connected to the collector of the transistor 44, the emitter of the transistor 44 is connected to the DC bus 24, and the diodes 45 and 46 are connected between the collectors and the emitters of the transistors 43 and 44, respectively. Has been done. The neutral point of the step-up / down chopper circuit 42 is connected to the positive terminal of the battery 13 via the reactor 47, and the negative terminal of the battery 13 is connected to the DC bus 24. The charging current detector 39
Is arranged in an electric path connecting the battery 13 and the reactor 47.

The high frequency isolation transformer 48 is an alternative to the high frequency isolation transformer 30, and the primary winding 48a and the secondary winding 48b are set to have the same number of turns. Both terminals of the primary winding 48a are connected to the AC output terminal of the high-frequency inverter circuit 29, and both terminals of the secondary winding 30b are connected to the AC input terminal of the full-wave rectifying circuit 49 which is a rectifying means. . The full-wave rectifier circuit 49 is configured by connecting four diodes 49a to 49d in a bridge connection. Among the positive and negative DC output terminals, the positive DC output terminal is the output terminal 25W of the inverter circuit 14. And the negative DC output terminal is connected to the input terminal 21 of the inverter circuit 14.

The battery voltage detector 50, which is a DC voltage detecting means, is connected between the positive and negative terminals of the battery 13 and detects the inter-terminal voltage Vdc of the battery 13. AC current detector 5 as AC side current detection means
1 is arranged in the AC power supply line 52 and detects the current flowing in the AC power supply line 52.
The zero-cross point sensor 54 composed of a photo cab is provided between the AC power supply lines 52 and 53.

Then, these battery voltage detectors 5
The output terminals of 0, the AC current detector 51, and the zero-cross point sensor 54 are connected to the input port of the control circuit 41, and the two output ports of the control circuit 41 are the transistor 43 of the step-up / step-down chopper circuit 42. It is connected to each base (gate) of 44.

Next, the operation of the second embodiment will be described with reference to FIG.

(1) Driving the induction motor 11 The basic operation of driving the induction motor 11 is the same as in the first embodiment. However, in this embodiment, the discharge current from the battery 13 is supplied to the inverter circuit 14 via the reactor 47 of the step-up / step-down chopper circuit 42 and the flywheel diode 45.

Further, the terminal voltage Vdc of the battery 13 detected by the battery voltage detector 50 is a set value (for example, 330).
If the voltage is smaller than the voltage, the control circuit 41 first supplies a base signal (gate signal) S5 to the transistor 44 of the step-up / step-down chopper circuit 42 to turn on the transistor 44. As a result, the positive terminal of the battery 13, the reactor 47, the transistor 44, and the battery 1
Electromagnetic energy is accumulated by the current flowing through the reactor 47 through the path of the negative terminal of No. 3. After that, the control circuit 41 comes to turn off the transistor 44 of the chopper circuit 42, the electromagnetic energy accumulated in the reactor 47 is accumulated in the capacitor 22 via the flywheel diode 45, and the voltage between the terminals of the capacitor 22 becomes the terminal. The voltage becomes higher than the inter-voltage Vdc. In this case, the control circuit 41 controls the on / off duty ratio of the transistor 44 of the chopper circuit 42 according to the degree of decrease in the inter-terminal voltage Vdc. Therefore, the chopper circuit 42 functions as a booster.

(2) Regenerative braking of induction motor 11 When the induction motor 11 shifts from a high output (high speed) to a low output (low speed), the induction motor 11 is regeneratively braked. That is, the control circuit 41
The transistor 43 of the chopper circuit 42 is turned on, and therefore the regenerative current from the induction motor 11 is transmitted to the battery 13 via the flywheel diodes 17U to 17W and 18U to 18W of the inverter circuit 14 and the transistor 43 of the chopper circuit 42. Comes to flow.

In this case, the power generation voltage of the induction motor 11 becomes proportional to the rotation speed at this time, so that the motor power generation voltage may be higher than the battery voltage of 330 volts. Therefore, the control circuit 41 causes the charging current detector 39 to operate the battery 1 during the regenerative braking.
3 detects the charging current (regenerative current) Id, and when it exceeds a predetermined value, turns off the transistor 43 of the chopper circuit 42, and conversely turns on the transistor 43 when the charging current Id is below a predetermined value. Control. Therefore, in this case, the chopper circuit 26 functions as a step-down device.

(3) Charging of Battery 13 When the commercial power supply 28 is connected to the high frequency isolated power supply circuit 26, the zero cross point sensor 54 is supplied with the AC power supply voltage Vac as shown in FIG. As shown in FIG. 5B, a rectangular wave output signal S that has a low level in the positive (+) half wave and a high level in the negative (−) half wave is output, and this is given to the control circuit 41. When the control circuit 41 detects that the output signal S from the zero-cross point sensor 54 repeats low level and high level, it determines that charging is started, and the transistor 16U of one arm 19U of the inverter circuit 14 and the chopper circuit 42 are determined. Transistor 43
Other than transistors 15U to 15W and 16V, 16
Turn off W. Further, as shown in FIG. 5B, the control circuit 41 outputs the output signal S from the zero cross point sensor 54.
The zero-cross point of the AC power supply voltage Vac is detected from the rising and falling edges of.

When the control circuit 41 detects a zero-cross point of the AC power supply voltage Vac, the control circuit 41 performs PLL control based on the detected zero crossing point, and as shown in FIG. 5C, a sine wave reference (voltage) synchronized with the AC power supply voltage Vac. Create signal VR. The control circuit 41 is adapted to judge the polarity of the AC power supply voltage Vac from the reference signal VR, and performs the following control based on this.

That is, the control circuit 41 applies the gate signal S2 to the high frequency inverter circuit 29 to generate the high frequency power supply voltage, as in the first embodiment. The high frequency power supply voltage is supplied by the high frequency isolation transformer 48. After being transformed into one-to-one, it is full-wave rectified by the full-wave rectification circuit 49, and as a direct current voltage, the output terminal 25 of the inverter circuit 14
It is applied between W and the input terminal 21.

When the AC power supply voltage Vac is a positive (+) half-wave, the control circuit 41 first sets the inverter circuit 14 to 1
The transistor 16U of one arm 19U is turned on.
As a result, the positive output terminal of the full-wave rectifier circuit 49, the stator coils 12W and 12U of the induction motor 11,
A current flows through the stator coils 12W and 12U through the path of the transistor 16U and the negative output terminal of the full-wave rectifier circuit 49, and electromagnetic energy is accumulated in the stator coils 12W and 12U. When a current flows through the stator coils 12W and 12U, the AC power supply lines 52 and 53
AC power supply current Iac also flows through this AC power supply current Ia
c is a detection current I detected by the AC current detector 51.
It is given to the control circuit 41 as b. The detection current Ib
Is actually converted into a voltage and given to the control circuit 41, but here, for convenience of description, the detection current I
b.

When the detection current Ib increases and becomes larger than the reference signal VR by continuing the ON state of the transistor 16U, the control circuit 41 turns off the transistor 16U and turns on the transistor 43. As a result, the electromagnetic energy stored in the stator coils 12W and 12U is given to the capacitor 22 via the flywheel diode 17U, and further given to the battery 13 via the transistor 43 and the reactor 47. Is charged with the boosted voltage.

After that, the detection current I of the AC current detector 51 is detected.
When b decreases and becomes smaller than the reference signal VR, the control circuit 4
1 again turns on the transistor 16U.
After that, the same operation is repeated. Therefore, the gate signal Sy given to the transistor 16U is as shown in FIG.
It becomes as shown in.

Even when the AC power supply voltage Vac is a negative (-) half wave, the transistors 16U and 43 by the control circuit 41 are used.
The on / off operation of is similar to that described above. Therefore, the gate signal Sz given to the transistor 16U is as shown in FIG.
It becomes as shown in.

That is, as shown in FIG. 5 (f), the control circuit 41 controls the on / off of the transistor 16U so that the detection current Ib follows the reference signal VR, whereby the detection current Ib is AC. The AC power supply current Iac is controlled by the sinusoidal waveform having the same phase as the power supply voltage Vac.
(G).

By the way, when the voltage Vdc between the terminals of the battery 13 is abnormally lowered at the time of charging the battery 13 as described above, an excessive charging current flows to the battery 13 to adversely affect the battery 13. Because it affects
The control circuit 41 operates as follows. That is, since the charging current detector 39 detects the charging current Id flowing in the battery 13 and supplies this to the control circuit 41, the control circuit 41
Controls ON / OFF of the transistor 43 of the chopper circuit 42 when the charging current Id exceeds a predetermined value, and thus controls the charging current Id to be a predetermined value or less.

(4) Floating Charging of Auxiliary Battery 33 The auxiliary battery 33 is floatingly charged by the dedicated charging circuit 35 when the induction motor 11 is driven (when the electric vehicle is running). In this case, the control circuit 41 controls the high frequency inverter circuit 36 in the same manner as the high frequency inverter circuit 31 (see FIG. 3).

As described above, according to the second embodiment, when the induction motor 11 is driven, when the terminal voltage Vdc of the battery 13 is lower than the set value, the chopper circuit 42 is made to act as a boosting chopper. Therefore, the induction motor 11 can be rated at the time of steady operation, and can be made efficient. Further, during regenerative braking of the induction motor 11, the chopper circuit 42 is made to act as a step-down chopper depending on the case where the generated voltage of the induction motor 11 is high, so that the regenerative braking of the induction motor 11 can be performed smoothly. The battery 13 is not adversely affected.

Further, when the battery 13 is charged, the transistor 16U of one arm 19U of the inverter circuit 14 serving as a drive circuit and the stator coils 12W and 12U of the induction motor 11 constitute a step-up chopper circuit to turn on / off the transistor 16U. Since the control is performed, a current flows intermittently in the stator coils 12W and 12U to accumulate electromagnetic energy, and the electromagnetic energy is given to the battery 13 via the transistor 43 of the chopper circuit 42 so that it is charged. become. Therefore, the battery 13 can be easily charged even with an external power source having a voltage lower than that of the battery 13, which is extremely advantageous for the user.

Further, when the battery 13 is being charged, the control circuit 41 detects the zero-cross point of the AC power supply voltage Vac based on the output signal of the zero-cross point sensor 54,
Based on this, the reference signal VR synchronized with the AC power supply voltage Vac is obtained, and the detection current Id of the AC current detector 51 for detecting the AC power supply current Iac is made to follow the reference voltage VR.

Therefore, even if the stator coils 12W and 12U of the induction motor 11 are used, the power factor of the AC power source can be controlled to be improved and the harmonics of the power source can be reduced. The charging current can also be controlled.

Further, the control circuit 41, when the battery 13 is being charged, and the inter-terminal voltage Vdc of the battery 13 is abnormally low, causes the transistor 43 of the chopper circuit 42 to operate.
Since the on / off control is performed, the rapid charging of the battery 13 can be prevented, and the battery 13
Has no adverse effect on

In the above embodiment, the induction motor 11 is used as the motor, but instead,
A two-phase motor, a brushless motor, or a reluctance motor may be used, and in this case, the drive circuit has only one arm formed by connecting two transistors, which are switching elements having flywheel diodes, in series. Therefore, the driving circuit is 1
Those having three or more arms are targeted.

[0071]

Since the present invention is as described above, it has the following effects. According to the battery charging device for an electric vehicle of claim 1, a high frequency power source is obtained from an external power source to be a primary side input of the high frequency isolation transformer, and a DC power source is obtained from a secondary side output of the high frequency isolation transformer to charge the battery. With this configuration, it is possible to reduce the size and weight of the battery, increase the mileage per charge of the battery, and improve the acceleration performance.

According to the battery charging device of the electric vehicle of the second aspect, at the time of charging the battery, the first winding and the second winding of the high frequency insulating transformer function as the primary side and the secondary side. The battery is charged on the basis of the high frequency voltage induced in the second winding, and when traveling by the battery,
Since the second winding and the third winding of the high frequency transformer function as the primary side and the secondary side to cause the auxiliary battery to be floatingly charged based on the high frequency voltage induced in the third winding, Both the battery and the auxiliary battery can be charged using one high-frequency insulating transformer.

According to another aspect of the battery charger for an electric vehicle of the present invention, the third winding of the high frequency insulating transformer functions as a secondary side even when the battery is being charged, and is used as an auxiliary device when the battery is being charged. The battery can float.

According to the battery charging device for an electric vehicle of the fourth aspect, the auxiliary battery drives the battery cooling fan, so that the battery can be cooled effectively.

According to the battery charging device for an electric vehicle of the fifth aspect, the auxiliary battery dedicated charging means for charging the auxiliary battery is provided, so that it corresponds to the number of auxiliary devices connected to the auxiliary battery. Can be made.

According to the sixth aspect of the battery charging apparatus for an electric vehicle, one of the auxiliary battery charging means and the auxiliary battery dedicated charging means operates normally, and the auxiliary battery has insufficient discharge capacity. Since the other operates at the time of, the floating charge of the auxiliary battery can be efficiently performed.

According to the battery charging device for an electric vehicle of claim 7 or 8, when the battery is charged, a part of the drive circuit is used to control the charging current, specifically, the power factor control. Therefore, it is possible to reduce power source harmonics.

According to the battery charging device for an electric vehicle of the ninth aspect, since the booster chopper circuit is configured by using the stator coil of the motor, the battery is charged even when the external power supply voltage is lower than the battery voltage. be able to.

According to the battery charging device for an electric vehicle of the tenth aspect, since the step-up / step-down chopper circuit is connected between the battery and the driving circuit, the voltage of the battery is boosted to drive the driving circuit when the motor is driven. The power generation voltage can be reduced and supplied to the battery during regenerative braking of the motor.

Further, according to the battery charging device for an electric vehicle of the eleventh aspect, when the battery voltage is lowered, the charging current of the battery is controlled by the step-down action of the step-up / step-down chopper circuit. It is possible to prevent an excessive charging current from flowing into the battery.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of the present invention.

FIG. 2 Partial electric circuit

FIG. 3 is a gate signal waveform diagram during charging of an auxiliary battery.

FIG. 4 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 5 is a signal waveform diagram of each part when charging the battery.

FIG. 6 is an electrical configuration diagram showing a conventional example.

[Explanation of symbols]

In the drawing, 11 is an induction motor (motor), 12
U to 12 W are stator coils, 13 is a battery, 14
Is an inverter circuit (driving circuit), 15U to 15W and 16U to 16W are transistors (switching elements), 17U to 17W and 18U to 18W are flywheel diodes, 19U to 19W are arms, 22
Is a capacitor, 26 is a high frequency insulation power supply circuit, 28 is a commercial power supply (external power supply), 29 is a high frequency inverter circuit (high frequency power generation means), 30 is a high frequency insulation transformer, and 30a.
Reference numerals 30 to 30c are first to third windings, 31 is a high frequency inverter circuit (rectifying means having a high frequency power generating function), 3
2 is a rectifier circuit (battery charging means for auxiliary equipment), 33 is a battery for auxiliary equipment, 34 is a battery cooling fan, 35 is a dedicated charging device (charging means for exclusive use of battery for auxiliary equipment), 42 is a step-up / down chopper circuit, and 48 is a high frequency insulating transformer. , 49 are rectifier circuits (rectifier means).

Claims (11)

[Claims] 1. An electric vehicle in which a traveling motor is driven via a drive circuit based on direct current power from a battery, and a high-frequency power source generating means for converting an external power source into a high-frequency power source, and the high-frequency generating means. And a high-frequency insulating transformer having a high-frequency power source as a primary input, and a rectifying means for rectifying a secondary output of the high-frequency insulating transformer to charge the battery. 2. The high frequency insulating transformer includes first to third windings, and the rectifying means has a high frequency power generating function for converting a DC power source of the battery into a high frequency power source. The first winding functions as a primary side to which the high frequency power source from the high frequency power source generating means is input and the second winding functions as a secondary side, and when the vehicle is driven by the battery, the second winding is the high frequency side from the rectifying means. The primary side for inputting a power source, and the third winding functions as a secondary side for inputting a high frequency power source to an auxiliary battery charging means for floatingly charging an auxiliary battery. Battery charger for electric vehicles. 3. The battery charging device for an electric vehicle according to claim 2, wherein the third winding of the high-frequency insulation transformer functions as a secondary side even when the battery is being charged. 4. The battery charging device for an automobile according to claim 2, wherein the auxiliary battery is adapted to drive a battery cooling fan for cooling the battery. 5. An auxiliary battery dedicated charging means for converting a DC power source of the battery into a high frequency power source and for stepping down and rectifying this to charge the auxiliary battery, in addition to the auxiliary battery charging means. The battery charging device for an electric vehicle according to any one of claims 2 to 4. 6. One of the auxiliary battery charging means and the auxiliary battery dedicated charging means operates normally, and the other operates when the auxiliary battery has insufficient discharge capacity. The battery charging device for an electric vehicle according to claim 5. 7. The battery charging of the electric vehicle according to claim 1, wherein the output side of the rectifying means is connected to a part of the drive circuit to control the charging current of the battery. apparatus. 8. The battery charging device for an electric vehicle according to claim 7, wherein the charging current of the battery is power factor controlled. 9. The battery charging device for an electric vehicle according to claim 7, wherein a part of the drive circuit constitutes a step-up chopper circuit by using a stator coil of the motor. 10. The battery charging device for an electric vehicle according to claim 7, wherein a buck-boost chopper circuit is connected between the battery and the drive circuit. 11. When the voltage of the battery drops,
11. The battery charging device for an electric vehicle according to claim 10, wherein the charging current of the battery is controlled by the step-down action of the buck-boost chopper circuit.