JPH089511A - Hybrid power source for motor-driven vehicle - Google Patents

Abstract

PURPOSE:To arbitrarily control the distribution of powers to be communicated between a first power source and a motor and between a second power source and the motor. CONSTITUTION:A power converter 3 for varying the output voltage of a first power source 20 is provided in the power source 20 so that the power source 209 supplies powers to a second power source 2 and a load 35 via a power converter 3. A controller 16 for controlling the voltage conversion ratio of the converter 3 is provided.

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]

According to a first aspect of the present invention, there is provided a first power source and a second power source connected to a load including a traveling electric motor. In the hybrid power supply device for an electric vehicle, which is configured such that power is supplied from a first power supply and power is supplied from the first and second power supplies to the load, the output voltage is supplied to the first power supply. In order to control the power distribution between the electric power supplied to the load from the first power source and the electric power supplied to the load from the second power source, the voltage variable means for changing the voltage is provided. It is characterized in that control means for controlling the variable means is provided.

According to one aspect of the first aspect of the present invention, the voltage varying means comprises a power converter, and the first power source is connected to the second power source and the load via the power converter. The control means is configured to supply electric power, and the control means includes means for controlling a voltage conversion ratio of the power converter.

The power converter is provided with means for electrically bypassing it.

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 according to the present application comprises a first power source having a power converter and a second power source connected to a load including a traveling electric motor, and the second power source supplies the above power. In a hybrid power supply device for an electric vehicle configured to be supplied with electric power via a converter, the electric power absorbed by the first power supply from the electric motor via the electric power converter; A control means for controlling the voltage conversion ratio of the power converter is provided in order to arbitrarily control the power distribution to the power directly absorbed by the second power source from the electric motor.

Also in this case, the power converter is provided with means for electrically bypassing it.

[0017]

According to the first invention of the present application, the power supplied from the first power supply to the load and the second power are supplied by the control means controlling the voltage varying means provided in the first power supply. Since it is possible to arbitrarily control the power distribution to the power supplied to the load from the two power sources, the performance of both power sources can be adjusted according to the running condition of the vehicle, the characteristics of the first and second power sources, and the internal conditions. It can be used properly so that it can be maximized.

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

In particular, 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.

[0021]

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 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
Current detection element 11 for detecting the output current of the first power supply 20
A current detection element 12 that detects the output current of the electric double layer capacitor 2 that is the second power source; and a current distribution detection circuit 13 that calculates the distribution of the currents detected by the two current detection elements 11 and 12. A comparison circuit 15 that compares a current distribution detection value obtained from the current distribution detection circuit 13 with a power distribution command value described later, and controls the voltage conversion rate of the chopper type power converter 3 based on the output of the comparison circuit 15. The voltage conversion rate controller 16 and the changeover switch control circuit 17 for actuating the changeover switch 4 are provided, 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 is k), the release voltage of the first power supply 20 is represented by kV ₁ and the internal resistance is represented by k ² R ₁ , and the equivalent circuit of FIG. 3B is obtained.

In FIG. 3B, the current supplied from the first power source 20 to the load 35 is I ₁ , the power is P ₁ , and the current supplied from the electric double layer capacitor 2 to the load 35 is I 1. ₂ , the 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, and the power distribution (power ratio) between the lead storage battery 1 and the electric double layer capacitor 2.
The relationship with P ₁ / P ₂ will be described. 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 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 increases, I ₁ increases and I ₂ increases 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, P ₂ is decreased, and P ₁ is decreased. ₁ / P ₂ can be increased. Further, when the voltage conversion rate k is decreased, P ₁ can be decreased, P ₂ can be increased, and P ₁ / P ₂ can be decreased.

The operation of the control circuit portion of the hybrid power source 30 will be described based on the above matters. In this control circuit portion, the current detection element 11 detects the current I ₁ supplied by the lead storage battery 1 to the load 35, the current detection element 12 detects the current I ₂ supplied by the electric double layer capacitor 2 to the load 35, In the current distribution detection circuit 13, the current distribution detection value (I ₁ / I
₂ ) Ask. Then, the power distribution command value (P ₁ / P ₂ ) from the input terminal 14 is compared by the comparison circuit 15, and (P ₁
If / P ₂ )> (I ₁ / I ₂ ), the voltage conversion rate controller 16 increases the voltage conversion rate k of the chopper type power converter 3 in the direction of (P ₁ / P ₂ ) <(I ₁ / I
_{If 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 electrically 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 the 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, as a general characteristic of the generator, since the field and the electromotive voltage are inversely proportional to each other, the throttle 44 keeps the engine 41 at a constant rotation speed, that is, the AC generator 46 has a constant rotation speed. 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.
It is possible to control the power distribution between the engine generator 50 and the electric double layer capacitor 2 at the output terminal 5 by the power distribution command input to the output terminal 4. 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, 12 Current Detection Element 13 Current Distribution Detection Circuit 15 Comparison Circuit 16 Voltage Conversion Rate Controller 20 First Power Supply 30 Hybrid Power Supply 31 Inverter 32 Induction Motor 34 Motor Controller 35 Load 40, 50 Engine Generator (First Power Source)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location H02J 1/00 306 K 7346-5G M 7346-5G

Claims (13)

[Claims] 1. A first power source, and a second power source connected to a load including a traveling electric motor, wherein the second power source is supplied with power from the first power source, and the first power source is provided. In a hybrid power supply device for an electric vehicle configured to supply power to the load from a second power supply, the first power supply is provided with voltage varying means capable of varying its output voltage, and the first power supply is provided. Control means for controlling the voltage varying means is provided to arbitrarily control the power distribution between the power supplied from the power supply to the load and the power supplied from the second power supply to the load. Hybrid power supply for electric vehicles. 2. The voltage varying means comprises a power converter, the first power supply is configured to supply power to the second power supply and the load via the power converter, and the control is performed. The hybrid power supply device for an electric vehicle according to claim 1, wherein the means comprises means for controlling a voltage conversion ratio of the power converter. 3. The hybrid power supply device for an electric vehicle according to claim 2, further comprising means for electrically bypassing the power converter. 4. The one of claims 1 to 3, 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. Hybrid power supply for electric vehicles. 5. The hybrid power supply device for an electric vehicle according to claim 4, wherein the first power supply includes a storage battery. 6. The hybrid for an electric vehicle according to claim 1, wherein the first power source includes an electric generator driven by an engine, and the voltage varying unit is a rotational speed control unit of the engine. Power supply. 7. The hybrid power source for an electric vehicle according to claim 1, wherein the first power source includes a generator driven by an engine, and the voltage varying means comprises field control means of the generator. apparatus. 8. The hybrid power supply device for an electric vehicle according to claim 4, wherein the second power supply is a capacitor. 9. A first power source including a power converter, and a second power source connected to a load including a traveling electric motor,
A hybrid power supply device for an electric vehicle configured to supply power from the second power supply to the first power supply via the power converter, wherein the first power supply is from the electric motor to the power converter. Control means for controlling the voltage conversion ratio of the power converter in order to arbitrarily control the power distribution between the electric power absorbed via the electric motor and the electric power absorbed by the second power source directly from the electric motor. A hybrid power supply device for an electric vehicle. 10. The hybrid power supply device for an electric vehicle according to claim 9, further comprising means for electrically bypassing the power converter. 11. The electric vehicle according to claim 9, 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. Hybrid power supply for car. 12. The hybrid power supply device for an electric vehicle according to claim 11, wherein the first power supply includes a storage battery. 13. The hybrid power supply device for an electric vehicle according to claim 11 or 12, wherein the second power supply is a capacitor.