JPH10292857A - Energy feeding system to variable load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy feeding system to a variable load which can follow the variation of the load. SOLUTION: In a normal condition, an even energy is fed to a variable load 4 from an energy source 1 such as a fuel cell. When the energy necessary to the variable load 4 is smaller than that in the normal condition, an excessive energy is absorbed and stored to an absorption-storing-feeding means 5. When the energy necessary to the variable load 4 is larger than that in the normal condition, the energy stored in the absorption-storing-feeding means 5 is fed to the variable load 4. That is, the variation part of the load which cannot be followed by the energy source 1 is covered by the energy stored in the absorption-storing-feeding means 5. By such an energy regulation, the energy utilizing efficiency of all the system is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a system for supplying energy from an energy source such as a fuel cell to a variable load having a large variation.

[0002]

2. Description of the Related Art There is an electric vehicle as a system for supplying energy to a variable load from an energy source such as a fuel cell having a small variation in supply.

[0003] An electric vehicle has a running motor as a variable load and a fuel cell as an energy source, and runs with electric energy supplied from the fuel cell to the motor.

[0004]

By the way, electric vehicles, like gasoline vehicles, start, accelerate, run at a constant speed, decelerate, brake, and stop. For this reason, the energy required by the motor also varies according to the running state. That is, a large amount of energy is required for starting and accelerating as compared with the case of traveling at a constant speed, and a smaller amount of energy is required for deceleration and braking as compared with the case of traveling at a constant speed.

However, when energy is supplied to the motor only by the fuel cell, the energy required by the motor at the time of starting or accelerating cannot be sufficiently supplied.
In order to supply sufficient energy to the motor during such acceleration, a fuel cell having a large capacity is required. However, when the volume of the fuel cell is increased, not only the living space in the automobile is reduced, but also the weight is increased, and there is a problem that the energy is consumed excessively, which is uneconomical.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide an energy supply system for a variable load that can follow a change in the load.

[0007]

According to the present invention, there is provided a system for supplying energy from an energy source such as a fuel cell to a variable load having a large variation.
Absorption, storage, and supply means for absorbing, storing, and supplying energy to fluctuating loads, and adjusting the energy between the energy source and the absorbing, storing, and supplying means for the fluctuating loads. A device is provided.

According to the present invention, in addition to the above configuration, the variable load may be a motor, and the absorbing / storing / supplying means may be a flywheel.

According to the present invention, in addition to the above configuration, the variable load may be a motor, and the absorbing, storing and supplying means may be a battery.

With the above configuration, in a steady state, average energy is supplied to the variable load from an energy source such as a fuel cell. If the energy required by the variable load is smaller than the steady state, the surplus energy is absorbed and stored in the absorption / storage / supply means. If the energy required by the variable load is larger than the steady state,
The energy stored in the supply means is supplied to the variable load. That is, the load fluctuation that cannot be followed by the energy source is covered by the energy stored in the absorption / storage / supply means. Such energy adjustment improves the energy use efficiency of the entire system.

[0011]

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

FIG. 1 is a block diagram showing an embodiment of an energy supply system for a variable load according to the present invention.

Reference numeral 1 denotes an energy source whose supply fluctuation is small (for example, a fuel cell). Reference numeral 2 denotes a converter (for example, a DC-DC converter) that converts the magnitude of the energy output from the energy source 1 into a constant magnitude. Reference numeral 3 denotes a converter (for example, a DC-AC converter and an AC-DC converter) for matching the energy supplied to the variable load (for example, an AC generator motor) 4 with the energy output from the energy source 1. is there. Reference numeral 5 denotes a system for absorbing, storing, and supplying the energy of the fluctuation (for example, a flywheel). 6 is a converter (e.g., DC-to-DC converter) for matching between the form of energy stored in the system 5 and the form of energy supplied to the variable load 4.
AC converter and AC-DC converter). 7
Is a control device for adjusting the energy between the energy source 1 and the system 5 for the variable load 4.

Next, the operation of the energy supply system will be described.

In the steady state, average energy is supplied from the energy source 1 to the variable load 4. Variable load 4
If the required energy is smaller than the steady state, excess energy is absorbed and stored in the system 5. If the energy required by the variable load 4 is larger than the steady state, the energy stored in the system 5 is
Supplied to That is, the load fluctuation that cannot be followed by the energy source 1 is covered by the energy stored in the system 5. Such energy adjustment improves the energy use efficiency of the entire system.

[0016]

FIG. 2 is a conceptual diagram showing an embodiment in which the energy supply system for a variable load according to the present invention is applied to an electric vehicle.

An electric vehicle 10 shown in FIG.
Motor (generator motor) 12 as a variable load for rotating the motor, converters (DC-AC converter and AC-DC converter) 13 connected to the AC motor 12 for converting DC to AC or AC to DC, A fuel cell 14 of about 1 kW for supplying average electric energy to the motor 12, a converter (DC-DC converter) 15 connected to the fuel cell 14 and converting the electric voltage to a predetermined voltage, and moving excess electric energy Absorption / storage as energy
A flywheel and generator motor 16 for supplying;
A converter (such as a DC-AC inverter) 17 that absorbs, stores, or supplies energy; a fuel cell 14; a flywheel and a generator motor 16;
And a control device 18 for integrally controlling the devices 15 and 17. 19 is a driven wheel, and 20 is an addition point.

The AC motor 12 is used as the motor because it is superior to a DC motor in terms of energy conversion efficiency and controllability. However, a DC motor may be used if it is a generator motor type. In the drawing, solid arrows indicate the flow of energy, and broken arrows indicate the flow of control signals. The arrow between the converter 13 and the addition point 20 is bidirectional because the electric energy generated when the AC motor 12 performs regenerative braking flows in the direction opposite to the direction of the electric energy from the fuel cell. It is. The arrows between the converter 17 and the addition point 20 are bidirectional because energy from the fuel cell 14 or the AC motor 12 is absorbed by the flywheel 16 or the flywheel 16 Energy is supplied to the

Next, the operation of the electric vehicle will be described.

When the electric vehicle 10 starts and runs, the control device 18 inputs the average DC electric energy from the fuel cell 14 to the converter 15 to convert it into a predetermined DC voltage. After that, it is input to the converter 13. Since the control device 18 causes the converter 13 to function as a DC-AC converter, the DC electric energy input to the converter 13 is converted into AC electric energy. The AC motor 1 is converted from the electric energy converted into AC by the converter 13.
2 rotates and the drive wheel 11 rotates.

When the electric vehicle 10 runs downhill or decelerates, the AC motor 12 performs regenerative braking and functions as a generator, so that electric energy is generated. Since the control device 18 causes the converter 13 to function as an AC-DC converter, AC electric energy generated by regenerative braking is converted into DC by the converter 13 and input to the converter 17 via an addition point. Since the converter 17 drives the generator motor 16 as a motor, the flywheel 16 rotates. That is, electric energy is converted into kinetic energy and absorbed and stored.

When the electric vehicle 10 is accelerated on an uphill or restarts after stopping, the control device 18 causes the generator 17 to function as a generator by the converter 17 and uses the kinetic energy stored in the flywheel 16 as electric energy. And supplied to the AC motor 12 together with the electric energy from the fuel cell 14.

In the above, the fuel cell 14 supplies the average energy to the AC motor 12, and the load fluctuation that cannot be followed by the fuel cell 14 is covered by the energy stored in the flywheel 16. This improves the efficiency of the entire system.

Although the present embodiment has been described with reference to an electric vehicle, the present invention is not limited to this, and may be applied to other devices and systems. In this embodiment, the flywheel is used as the absorption / storage / supply means.However, the present invention is not limited to this, and a secondary battery such as a lead storage battery or a nickel cadmium battery may be used. The converter 17 becomes unnecessary.

[0025]

In summary, according to the present invention, the following excellent effects are exhibited.

Absorption, storage and supply of energy
By providing the storage / supply means in parallel and the control means for adjusting the energy between the energy source and the absorption / storage / supply means for the fluctuating load, it is possible to follow the fluctuation of the load. The provision of an energy supply system for a variable load can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an energy supply system for a variable load according to the present invention.

FIG. 2 is a conceptual diagram showing an embodiment in which the energy supply system for a variable load according to the present invention is applied to an electric vehicle.

[Explanation of symbols]

Reference Signs List 1 energy source (fuel cell) 2, 3, 6 converter 4 fluctuating load (AC motor) 5 absorption / storage / supply means (system for absorbing / storing / supplying fluctuating energy) 7 controller

Claims (3)

[Claims] 1. A system for supplying energy from an energy source such as a fuel cell to a fluctuating load having large fluctuations, wherein absorption, storage, and supply means for absorbing, storing, and supplying energy to the fluctuating load are provided in parallel. An energy supply system for a fluctuating load, comprising a control device for adjusting energy between the energy source and the absorption / storage / supply means for the fluctuating load. 2. The energy supply system according to claim 1, wherein the variable load is a motor, and the absorption / storage / supply means is a flywheel. 3. The energy supply system according to claim 1, wherein the variable load is a motor, and the absorption / storage / supply means is a battery.