JP3389324B2 - Hybrid power supply for electric vehicles - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid power supply device for driving an electric vehicle equipped with a traveling electric motor, which drives the electric motor by a hybrid power supply in which two or more power supplies are combined.

[0002]

2. Description of the Related Art In an electric vehicle which is required to run for a long time and has a large load variation, a hybrid power source is used which is a combination of two or more power sources which meet the respective requirements. That is, the traveling electric motor is driven by the first power source (also referred to as energy power source) suitable for long-time small-power charging / discharging and the second power source (also referred to as power power source) suitable for short-time large-power charging / discharging. Is being driven.

The second power source is connected to a load including a traveling electric motor, the second power source is supplied with electric power from the first power source, and the load is fed with the first and second electric power sources. The power is supplied from the second power supply.

In that case, a power converter for the purpose of protecting the first power supply and managing the amount of electricity stored in the second power supply is installed between the first power supply and the second power supply, First power supply and second
Conventionally, a large number of hybrid power sources have been proposed in which the transfer of electric power to and from the power source is restricted.

An example of this kind of hybrid power source is disclosed in Japanese Patent Application Laid-Open No. 5-30608. In this hybrid power source, a storage battery is used as the first power source and a large capacity capacitor is used as the second power source. During deceleration of an electric vehicle equipped with this hybrid power source, the share of rapid discharge / charge to the capacitor is increased by limiting the charging of regenerative power to the storage battery by the power converter. As a result, even if the storage battery does not have a capacity for large acceleration / deceleration, a large-capacity capacitor can be used, and quick charging of the storage battery can be avoided to prevent deterioration of the storage battery.

[0006]

By the way, in the electric vehicle that is driven by the hybrid power source described above,
A first power source such as a storage battery, which is suitable for long-time low-power charging / discharging, and a second power source, which is suitable for short-time high-power charging / discharging, and a first power source, are provided for driving conditions of the vehicle and It is necessary to determine the power distribution of both power sources in order to maximize the characteristics of each power source, taking into consideration the internal conditions of the power sources.

However, since the conventional hybrid power source is provided with only the power converter for limiting the transfer of the power between the first power source and the second power source, the first power source and the second power source are provided. There is a problem in that the distribution of electric power exchanged between the second power source and the electric motor cannot be arbitrarily adjusted.

[0008] In addition, the power converter installed between the first power source and the second power source always causes a power loss between the first power source and the electric motor due to power conversion. There was also a problem that the energy held by the first power source could not be effectively utilized.

In view of the above-mentioned circumstances, the first object of the present invention is to provide electric power exchanged between the first power source and the electric motor and electric power exchanged between the second power source and the electric motor. Allocation
An object of the present invention is to provide a hybrid power supply device for an electric vehicle that can be arbitrarily controlled.

A second object of the present invention is to provide a hybrid power supply device for an electric vehicle that eliminates power loss when the first power supply is provided with a power converter.

[0011]

First invention relating to the present application
Is a load including the electric motor for traveling and the load connected to the load.
A motor controller that controls the line motor and the load
Connected to the first electric power source for supplying electric power to the traveling electric motor.
Source and power to the drive motor connected to the load.
And a second power supply for supplying power, wherein the first power supply is a second power supply.
It is a power source that has a low power type characteristic for a long time compared to the source,
And power is supplied to the second power supply from the first power supply.
Hybrid power supply for electric vehicles
The output voltage of the first power supply can be varied.
In addition to providing the voltage varying means consisting of a power converter,
First current detecting element for detecting an output current from the first power supply
And a second current detector that detects the output current from the second power supply.
An output element, the first current detection element and the second current
Based on the signal from the detection element and the power distribution command from the outside
The power supplied from the first power source to the load.
Power distribution with the power supplied from the second power source to the load
Control to control the voltage varying means in order to arbitrarily control the minute
Control means is provided, and the first power source is the power conversion
Power to the second power source and the load via a power supply
And the control means includes the power converter.
And a means for controlling the voltage conversion ratio of
In addition, the power converter is provided with means for electrically bypassing the power converter .

According to another aspect of the first invention, the first power source includes an electric generator driven by an engine. In that case, the voltage varying means is composed of the engine speed control means or the generator field control means.

A second invention relating to the present application provides a power converter.
Connected to the first power source provided and to the load including the traction motor.
And a second power source that is connected to the power source.
Power is supplied to the first power source through the converter
In the hybrid power supply device for an electric vehicle,
A first power source draws power from the electric motor through the power converter.
A first current detecting element for detecting electric power to be collected,
The electric power that the second power source directly absorbs from the traveling electric motor.
A second current detecting element for detecting the
Signals from the current detection element and the second current detection element of
Based on the power distribution command from the department,
Power absorbed through the power converter and the second power source
Arbitrarily allocates power to the power directly absorbed by the motor
To control the voltage conversion ratio of the above power converter.
The control means will be provided that further includes a feature that means for electrically bypassing said power converter is provided
To do.

[0014]

According to the first invention of the present application, the control means controls the voltage varying means provided in the first power supply, so that the load including the traveling electric motor is supplied from the first power supply. Power distribution between the electric power supplied to the load including the traveling motor from the second power source and the electric power distribution of the first and second power sources and the internal state of the vehicle can be controlled arbitrarily. Depending on the situation, both power supplies can be used to maximize their performance.

Therefore, the electric vehicle equipped with this hybrid power supply device can obtain a long cruising range and can exhibit agile acceleration / deceleration performance.

Particularly, when the first power source is provided with a power converter as the voltage varying means and the power converter is provided with means for electrically bypassing the power converter, it is not necessary to use both power sources properly. By electrically bypassing the power converter, power conversion loss due to the power converter can be eliminated, so that an electric vehicle having a longer cruising range can be obtained.

According to the second invention of the present application, the control means controls the power converter provided in the first power supply, so that the power absorbed by the first power supply from the electric motor via the power converter. Since it is possible to arbitrarily control the power distribution between the second power source and the power directly absorbed from the electric motor, the electric power of the electric motor can be adjusted according to the running condition of the vehicle, the characteristics of the first and second power sources, and the internal condition. Both power sources can use the electric power generated by the regenerative function to the maximum extent, and it is possible to extend the cruising range of the electric vehicle and improve the acceleration / deceleration performance. Also in this case, the cruising distance of the electric vehicle can be further extended by providing the electric power converter with means for electrically bypassing the electric power converter.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of a hybrid power supply type electric vehicle equipped with a hybrid power supply device according to the present invention. In FIG. 1, a hybrid power supply type electric vehicle 100 includes a DC type hybrid power supply 30 described later.
An inverter 31 for converting DC power output from the hybrid power source 30 into AC power, and an inverter 3
The vehicle 10 is rotated by the AC power output from the vehicle 10.
The induction motor 32 that drives 0, the accelerator pedal 33 for adjusting the acceleration and deceleration of the vehicle 100, and the inverter 32 that drives the electric motor 32 according to the depression amount of the accelerator pedal 33.
The motor controller 34, which is controlled via the control unit 1, the speed reducer 60, the drive shaft 61, and the four wheels 62. Hereinafter, for convenience of description, a combination of the inverter 31 and the electric motor 32 for traveling is referred to as a load 35, and power consumed by the load 35 during power running or power generated during regeneration is denoted by P.

FIG. 2 is a block diagram showing a first embodiment of a hybrid power supply device for an electric vehicle according to the present invention.
The embodiment shown in FIG. 2 is one in which the hybrid power source 30 is configured by focusing on the case where the induction motor 32 in FIG.

The hybrid power source 30 is roughly divided into a main circuit portion and a control circuit portion. The main circuit portion is suitable for a lead storage battery 1 suitable for long-time small-power charging / discharging and a short-time large-power charging / discharging. The electric double layer capacitor 2, the chopper type power converter 3 for supplying electric power from the lead storage battery 1 to the electric double layer capacitor 2, and the chopper type power converter 3 are electrically bypassed, and the lead storage battery 1 and the electric storage battery 1 are electrically connected. The output of the hybrid power supply device 30 is supplied from the electric double layer capacitor 2 to the load 35 via the output terminals 5 and 5, which is configured by the changeover switch 4 that connects the double layer capacitor 2 in parallel.
Here, a combination of the lead storage battery 1 and the chopper type power converter 3 is called a first power supply 20, and the electric double layer capacitor 2 is called a second power supply.

The control circuit portion of the hybrid power source 30 is
A first current detection element 11 that detects the output current of the first power source 20, a second current detection element 12 that detects the output current of the electric double layer capacitor 2 that is the second power source, and two current detection elements A current distribution detection circuit 13 for calculating distribution of currents detected by the elements 11 and 12, and a current distribution detection circuit 1
3, a comparison circuit 15 for comparing the current distribution detection value obtained from 3 with a power distribution command value described later, and a voltage conversion rate for controlling the voltage conversion rate of the chopper type power converter 3 based on the output of the comparison circuit 15. Controller 16 and changeover switch 4
And a changeover switch control circuit 17 for activating the power supply, and a power distribution command from the outside is input to the comparison circuit 15 via the input terminal 14.

FIG. 3 is a diagram showing an electrically equivalent circuit of the main circuit portion of the hybrid power source 30. When the movable contact of the changeover switch 4 in FIG. 2 is on the a side, the chopper-type power converter 3 is electrically bypassed, so the first power supply 2
0 indicates only the lead storage battery 1, and the lead storage battery 1 and the electric double layer capacitor 2 are connected in parallel. The release voltage of the lead storage battery 1 is V ₁ , the internal resistance is R ₁ , the electric double layer capacitor 2 Let V _{2 be} the release voltage and R ₂ be the internal resistance, then the equivalent circuit of FIG. In addition, when the movable contact of the changeover switch 4 in FIG. 2 is on the b side, the chopper-type power converter 3 theoretically converts the voltage to k times (output voltage / input voltage) while keeping the power (voltage When the conversion rate k), the release voltage of the first power supply 20 is kV ₁ , and the internal resistance is k ²
Represented by R ₁ , the equivalent circuit of FIG. 3 (B) is obtained.

Here, in FIG. 3B, the current supplied from the first power source 20 to the load 35 is I ₁ , the power is P ₁ ,
The electric current supplied from the electric double layer capacitor 2 to the load 35 is I ₂ , the electric power is P ₂ , the terminal voltage of the load 35 is V, the voltage conversion rate k of the chopper type power converter 3, the lead storage battery 1 and the electric two. Power distribution (power ratio) P ₁ / P ₂ with multilayer capacitor ₂
The relationship with is explained. Since the chopper type power converter 3 stores electric power, the electric power supplied from the lead storage battery 1 to the load 35 is equal to the electric power P ₁ supplied from the power source 20 to the load 35.

First, for the terminal voltage V of the load 35, the following equation is established.

V = kV ₁ −k ² R ₁ I ₁ (lead storage battery 1) = V ₂ −R ₂ I ₂ (electric double layer capacitor 2) = P / (I ₁ + I ₂ ) (load 35) (1) Equation (2) is derived from the first and second rows of equation (1).

I ₂ = (k ² R ₁ I ₁ −kV ₁ + V ₂ ) / R ₂ (2) The equation (2) is differentiated by k to obtain the equation (3).

ΔI ₂ / δk = (2kR ₁ I ₁ −V ₁ ) / R ₂ (3) From formula (3), formula (4) is obtained in the range of k <V ₁ / (2R ₁ I ₁ ). .

ΔI ₂ / δk <0 (4) Equation (5) is derived from the second and third rows of equation (1).

I ₁ = P / (V ₂ −R ₂ I ₂ ) −I ₂ (5) Equation (5) is differentiated by I ₂ to obtain equation (6).

ΔI ₁ / δI ₂ = PR ₂ / (V ₂ −R ₂ I ₂ ) ² −1 = PR ₂ / V ² −1 (6) From the formula (6), the range of P <V ² / R ₂ Equation (7) is obtained with.

ΔI ₁ / δI ₂ <0 (7) From equations (7) and (4), equation (8) is obtained.

ΔI ₁ / δk = (δI ₁ / δI ₂ ) (δI ₂ / δk)> 0 (8) From equations (8) and (4), when k is increased, I ₁ is increased and I ₂ is It will decrease and the current distribution I ₁ / I ₂ will increase. When k decreases, I ₁ decreases, I ₂ increases, and current distribution I ₁ / I ₂ decreases.

Next, the distribution P of the power P consumed by the load 35
_{Since the} equation (9) holds for ₁ / P ₂ , the current distribution I ₁ / I ₂ is nothing but power distribution.

P ₁ / P ₂ = (VI ₁ ) / (VI ₂ ) = I ₁ / I ₂ (9) Therefore, when the voltage conversion rate k is increased, P ₁ is increased and P ₂ is decreased, P ₁ / P ₂ can be increased. Also, when the voltage conversion rate k is decreased, P ₁ is decreased,
P ₂ increases, it is possible to reduce the P ₁ / P _2.

Based on the above matters, the operation of the control circuit portion of the hybrid power source 30 will be described. In this control circuit portion, the lead storage battery 1 is connected to the load 3 by the first current detection element 11.
The second current detection element 1 that detects the current I ₁ supplied to the
At 2, the electric double layer capacitor 2 detects the current I ₂ supplied to the load 35, and the current distribution detection circuit 13 obtains the current distribution detection value (I ₁ / I ₂ ). Then, the power distribution command value (P ₁ / P ₂ ) from the input terminal 14 is compared by the comparison circuit 15,
If (P ₁ / P ₂ )> (I ₁ / I ₂ ), (P ₁ / P ₂ ) <in the direction of increasing the voltage conversion rate k of the chopper type power converter 3 by the voltage conversion rate controller 16. (I ₁ /
If I ₂ ), the voltage conversion rate controller 16 sequentially feedback-controls the power distribution in the direction of decreasing the voltage conversion rate k of the chopper type power converter 3. As a result, the hybrid power source 30 receives the power distribution command input to the input terminal 14 from the outside,
Power distribution between the lead storage battery 1 and the electric double layer capacitor 2 can be controlled.

As described above, when the movable contact of the changeover switch 4 is on the side b, the power distribution can be controlled by the chopper type power converter 3, but the power of the lead storage battery 1 is necessarily chopper. Since power loss occurs due to power conversion in the formula power converter 3, when the lead storage battery 1 is used for a long time, cumulative power loss, that is, energy loss cannot be ignored. Therefore, in this embodiment, when it is not necessary to control the power distribution, the movable contact of the changeover switch 4 is switched to the a side, and the hybrid power source 30 is switched to the one shown in FIG.
As the connection shown in (1), the unnecessary chopper type power converter 3 is electrically bypassed to eliminate power loss.

FIG. 4 is a block diagram showing a second embodiment of the hybrid power supply device for an electric vehicle according to the present invention.
In the present embodiment, the hybrid power supply 30 is configured by focusing on the case where the induction motor 32 in FIG. 1 performs a regenerative operation.

When the hybrid power supply type electric vehicle 100 decelerates and brakes and regenerates, the induction motor 32 generates electric power.
In the embodiment shown in (1), the load 35 generates electric power. That is, in the first embodiment shown in FIG. 2, the electric power was supplied from the hybrid power source 30 to the load 35, but in the second embodiment shown in FIG.
Power is supplied to the hybrid power source 30 from the
The position of the changeover switch 4 and the input / output direction of the chopper type power converter 3 are different between the configuration of FIG. 2 and the configuration of FIG. 4, and the output terminal 5 becomes the input terminal 6. Other configurations are
Since FIG. 4 and FIG. 2 are the same, duplicate description will be omitted. Further, since the electrical equivalent circuit of the configuration of FIG. 4 can also be represented in FIG. 3, the same control can be performed in equations (1) to (9) only by reversing the sign of the current.

FIG. 5 is a block diagram showing a third embodiment of the hybrid power supply device for an electric vehicle according to the present invention.
In the first embodiment shown in FIG. 2, the first power supply 20 is composed of the lead storage battery 1 and the chopper type power converter 3, whereas in the present embodiment, the first power supply is The engine generator 40 is used. That is, the engine generator 40 is driven by the engine 41 via the engine 41, the fuel tank 42 and the fuel pipe 43 that supply fuel to the engine 41, the throttle 44 that adjusts the output of the engine 41, and the coupling shaft 45. And an rectifier 47 that converts the alternating current generated by the alternating current generator 46 into direct current.

By adjusting the opening of the throttle 44 based on the output of the comparison circuit 15, the rotation speed of the engine 41, that is, the rotation speed of the AC generator 46 is adjusted. In this case, as a general characteristic of the generator, the electromotive voltage is proportional to the rotational speed when the field is constant, so that the output voltage of the engine generator 40 can be controlled by the throttle 44. Therefore, the hybrid power source 30 shown in FIG. 5 can control the power distribution between the engine generator 40 and the electric double layer capacitor 2 at the output terminal 5 according to the power distribution command input from the outside to the input terminal 14. Functions similar to those of the first embodiment shown in FIG. 2 are realized.

FIG. 6 is a block diagram showing a fourth embodiment of a hybrid power supply device for an electric vehicle according to the present invention.
Also in this embodiment, the engine generator 50 is used as the first power source, and the elements corresponding to those in FIG.
Although redundant description is omitted, in the case of the present embodiment, the rotation speed of the engine 41 is kept constant by the throttle 44, and the field control circuit 51 is provided to control the field of the AC generator 46.

In this case, since the field and the electromotive voltage are inversely proportional to each other as a general characteristic of the generator, the engine speed of the engine 41 is kept constant by the throttle 44, that is, the engine speed of the AC generator 46 is constant. In this state, the field control circuit 51 controls the field of the AC generator 46 on the basis of the output of the comparison circuit 15.
An output voltage of 0 can be controlled. Therefore, the hybrid power source 30 shown in FIG.
4 can control the power distribution between the engine generator 50 and the electric double layer capacitor 2 at the output terminal 5 according to the power distribution command input to the output terminal 5. The same function as that of the third embodiment is realized.

Although the configuration and operation of the embodiment of the present invention have been clarified by the above description, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made. That is, as the battery included in the first power source 20, not only the lead storage battery 1 but also a secondary battery having a high energy density such as a lithium battery, a sodium-sulfur battery, a zinc-air battery, a fuel cell, a solar cell, or the like is used. May be. Further, the second power source is not limited to the electric double layer capacitor 2, but a secondary battery having a high power density such as a nickel cadmium battery, an electrolytic capacitor, a flywheel battery, or the like may be used. This flywheel battery is a combination of a flywheel that rotates at a high speed and an electric motor, and can convert electric energy into inertial energy of the flywheel for storage, and can convert this inertial energy into electric energy for extraction. Further, the power converter is not limited to the chopper type power converter 3, but an inverter type power converter or a DC / DC converter type power converter may be used. Of course, the power converter can be configured to have both the function of the chopper type power converter 3 shown in FIG. 2 and the function of the chopper type power converter 3 shown in FIG.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a hybrid power supply type electric vehicle equipped with a hybrid power supply device according to the present invention.

FIG. 2 is a block diagram showing a first embodiment of a hybrid power supply device according to the present invention.

FIG. 3 is a diagram showing an electrical equivalent circuit of a main circuit portion of the hybrid power supply of FIG.

FIG. 4 is a block diagram showing a second embodiment of the hybrid power supply device according to the present invention.

FIG. 5 is a block diagram showing a third embodiment of a hybrid power supply device according to the present invention.

FIG. 6 is a block diagram showing a fourth embodiment of a hybrid power supply device according to the present invention.

[Explanation of symbols]

1 Lead acid battery 2 Electric double layer capacitor (second power supply) 3 Chopper type power converter 4 changeover switch 11 First current detection element 12 Second current detection element 13 Current distribution detection circuit 15 Comparison circuit 16 Voltage conversion rate controller (control means) 20 First power supply 30 hybrid power supply 31 inverter 32 induction motor (running motor) 34 Motor Controller 35 load 40, 50 engine generator (first power supply)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H02J 1/00 306 H02J 1/00 306M H01G 9/00 301Z (56) Reference JP-A-5-222964 (JP, A) Kaihei 4-271209 (JP, A) JP 51-39813 (JP, A) JP 5-146008 (JP, A) JP 6-78408 (JP, A) JP 51-32926 ( (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60K 6/04 B60L 11/00-11/18 H01G 9/155 H02J 1/00 306

Claims (7)

(57) [Claims] 1. A load including a traveling electric motor and a connection to the load.
Motor controller that is continued to control the electric motor for traveling
And connected to the load to supply power to the electric motor for traveling
Connected to the load and the first power source
A second power source for supplying electric power to the machine,
The source has long time low power type characteristics compared to the second power source
A power source, and the second power source is powered from the first power source.
A hybrid for an electric vehicle configured to be supplied with power.
In a power supply unit, a power converter capable of varying its output voltage with a first power supply.
With the voltage varying means,
Of the first current detecting element for detecting the output current of the
A second current detecting element for detecting the output current from the source
From the first current detection element and the second current detection element
Based on the signal of the
Power supplied to the load from the second power supply and the second power supply
Control the power distribution to the power supplied to the above loads from
Control means for controlling the voltage varying means
Te becomes, the first power source, the second through the power converter
Configured to power the power source and the load,
The control means controls the voltage conversion ratio of the power converter
Together consisting means, further, the power converter electrically hybrid power supply device for you, wherein electrostatic dynamic vehicle that means for bypassing is provided a. 2. The hybrid power supply device for an electric vehicle according to claim 1 , wherein the first power supply includes a storage battery. 3. The hybrid power supply device for an electric vehicle according to claim 1 , wherein the second power supply is a capacitor. 4. A first power supply having a power converter, and running.
A second power source connected to the load including the electric motor,
From the second power source to the first power source via the power converter.
Electric vehicle housings configured to be powered by a power source
In the hybrid power supply device, the first power source is from the electric motor through the power converter.
First current detecting element for detecting electric power absorbed by
And the second power source absorbs directly from the traveling electric motor.
A second current detecting element for detecting the electric power
Signals from the first current detection element and the second current detection element
No. 1 and the external power distribution command,
The power absorbed by the source through the power converter and the second power
Power distribution with the power directly absorbed by the above power source from the motor
In order to arbitrarily control the
It is provided with a control means for controlling further the power converter electrically hybrid power supply device for you, wherein electrostatic dynamic vehicle that means for bypassing is provided a. 5. The hybrid for an electric vehicle according to claim 4 , wherein the first power source has a long-time low-power type characteristic and the second power source has a short-time high-power type characteristic. Power supply. 6. The hybrid power supply device for an electric vehicle according to claim 5 , wherein the first power supply includes a storage battery. 7. The hybrid power supply device for an electric vehicle according to claim 5 or 6 said second power supply is characterized by consisting of a capacitor.