JPH06124720A - Hybrid power supply device - Google Patents

Abstract

PURPOSE:To provide a hybrid power supply device capable of stable power supply. CONSTITUTION:This power supply device is equipped with the first and second batteries 46 and 47 for supplying power to the outside of an electric vehicle such as a control section 15 via an output terminal 12, and a fuel cell 48 for charging both batteries 46 and 47. Power is supplied to the control section 15 from one of the batteries 46 and 47 via the terminal 12 by changing over the first and second switches 51 and 52, while the other battery is charged with the fuel cell 48. Also, the control section 15 monitors the capacity of either battery at a power supply process. When the capacity drops to or below the predetermined value, a selector signal S is outputted from the section 15, thereby selecting the connections of the first and second switches 51 and 52.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, for example, a power supply device used for driving a motor of an electric vehicle.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of protecting the environment of the earth, electric vehicles that do not use an engine that causes exhaust gas as a drive source but that drive a vehicle with clean electric power have attracted attention. In an electric vehicle, generally, electric power supplied from a large-capacity storage battery causes a motor to rotate to provide a driving force for the vehicle. By the way, a storage battery used in an electric vehicle has a large output capacity but a relatively small energy capacity, as indicated by line A in FIG. Therefore, in an electric vehicle that uses a storage battery as a power source, the distance that can be traveled by one charge is around 100 km, and the distance that an existing gasoline vehicle that runs on an engine using gasoline as fuel is 400 km.
There is a considerable difference compared to ~ 500 Km.
Therefore, in order to extend the possible travel distance, as shown by the line B in FIG. 6, a power supply device in which a fuel cell having a small output capacity but a large energy capacity and a storage battery are combined has been developed. Such a hybrid power supply device is experimentally used in, for example, a bus and a golf cart.

FIG. 7 shows an outline of an electric vehicle equipped with a conventional hybrid power supply device in which such a storage battery and a fuel cell are combined. As shown in this figure, an electric vehicle includes a hybrid power supply device 1, and the electric power of the hybrid power supply device 1 is controlled by a motor 2 under the control of a control unit 2 including an inverter, a CPU (central processing unit), and the like. 3 is driven. In the hybrid power supply device 1, a fuel cell 5 and a battery 6 are arranged in parallel via a diode 4 for preventing backflow. Then, electric power is selectively supplied to the control unit 2 by the fuel cell 5 and the battery 6 according to the traveling conditions of the electric vehicle. That is, when low output power is sufficient, power is supplied from the fuel cell 5 which is advantageous in terms of energy capacity, and when high output power is required, power is supplied from the battery 6 which is advantageous in terms of output capacity. There is. This is because the fuel cell 5 has a small output density but a high energy density, and thus is advantageous if the load is small. On the other hand, since an electric vehicle needs to have acceleration and gradeability comparable to that of a gasoline vehicle, it may require a large amount of electric power. In such a case, a storage battery having a high output density is used.

[0004]

However, the conventional hybrid power supply device has the following problems. That is, in the case of a phosphoric acid type fuel cell, for example, since it normally operates stably at a high temperature of about 180 degrees, it takes time to start. Therefore, there is a problem that it is difficult to obtain an output from the fuel cell 5 at the time of starting. Further, in the conventional hybrid power supply device, it is difficult to cope with the load fluctuation.
That is, normally, the conditions for obtaining the maximum power from the fuel cell are within a very limited range. On the other hand, the motor load of an electric vehicle is extremely variable depending on the starting time and the vehicle speed, and it is difficult to always maintain the maximum efficiency of the fuel cell. Further, a large fuel cell was required to obtain the driving force. For example, 1t at a vehicle speed of 50km / hr
On car requires about 4Kw of driving energy,
If you try to supply this with a fuel cell,
It was necessary to mount a fuel cell of 300 kg, which led to a decrease in traveling distance. Further, in the conventional hybrid power supply device, the fuel cell and the battery are arranged in parallel, and the load is abruptly switched according to the running condition, so that the fuel cell is operated at the maximum efficiency while maintaining a stable operating point. It was not possible to drive while charging the storage battery with the battery.

As described above, it is difficult for the conventional hybrid power supply device to stably supply electric power to, for example, an electric vehicle. Therefore, an object of the present invention is to provide a hybrid power supply device capable of supplying electric power in a stable manner.

[0006]

According to the present invention, an output terminal for supplying electric power to the outside, such as a control unit for controlling the driving of a motor in an electric vehicle, is charged and discharged, for example, 2
A plurality of power storage means including a secondary battery, a capacitor, a combination of a secondary battery and a capacitor, a fuel cell for charging any of these power storage means, and one of the power storage means to select the output terminal. To the hybrid power supply device, and a first connecting means for connecting to the fuel cell and a second connecting means for selecting any one of the power storage means not connected to the output terminal by the first connecting means and connecting to the fuel cell. In order to achieve the above purpose.

[0007]

In the present invention, any one of the plurality of power storage means is connected to the output terminal by the first connection means to supply electric power to the outside of the electric vehicle or the like. Then, one of the other power storage means is connected to the fuel cell by the second connection means, and the fuel cell is charged. As a result, the fuel cell can always be stably operated with maximum efficiency under the same load condition, and moreover, the fuel cell can have a capacity necessary for charging and the weight can be reduced. Further, the control of the gas body by the auxiliary device of the fuel cell, which corresponds to the load fluctuation, does not become complicated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the hybrid power supply device of the present invention will be described in detail below with reference to FIGS. FIG. 1 shows a drive control system of an electric vehicle using an embodiment of a hybrid power supply device. As shown in FIG. 1, the electric vehicle includes a hybrid power supply device 11 that is a target of the present embodiment, and the hybrid power supply 11 has a control unit 1 via an output terminal 12.
It is connected to 5. The electric power supplied from the hybrid power supply device 11 is converted into a three-phase alternating current through the smoothing capacitor 34 and the bridge circuit 20 including the power transistors 21 to 26, and the brushless DC motor 13
To be supplied to. The rotating shaft of the brushless DC motor 13 is connected to the drive mechanism of the electric vehicle and also to the resolver 16 as a rotor position detector. The resolver circuit 18 excites the resolver 16 and inputs the resolver signal a, and the current waveform control circuit 1
The signal b indicating the excitation position is output to the signal 9.

The main computer 29 has various signals e1 to e5, such as signals from a speed sensor for detecting the accelerator pedal depression amount and the speed of the vehicle, as well as various voltage value signals v from a voltage detection circuit 31. The detection signal is input. In response to each of these signals e and v, the main computer 29 causes the current command signal j1 for commanding the required current,
The rotation direction command signal j2, the regeneration signal j3, and the operation command signal j4 are supplied to the current waveform control circuit 19.

The current waveform control circuit 19 controls so that the brushless DC motor 11 is supplied with a current corresponding to the load condition of the hybrid type vehicle, for example, the depression amount of the accelerator or the brake, to obtain a predetermined torque. Circuit. That is, the current waveform control circuit 19 based on these signals j, the pulse width modulation (PWM) signal d of the UVW phase having the duty ratio corresponding to the required current.
Is output to the base drive circuit 25. The base drive circuit 28, in accordance with the PWM signal d, causes the power transistors 21 to
Drive 26. The voltage detection circuit 31 includes an analog-digital conversion circuit (not shown), and directly detects the voltage of the battery of the hybrid power supply device 11, converts the detected voltage into a digital value, and outputs the voltage value signal v. Has become.

Next, the configuration of the hybrid power supply device 11 in this embodiment will be described with reference to FIG. The hybrid power supply device 11 includes a first battery 46 and a second battery 47 as power supply sources that supply power to the control unit 15.
Is equipped with. These first and second batteries 46, 4
7, lead acid storage battery, nickel cadmium battery, sodium sulfur battery, lithium secondary battery, hydrogen secondary battery,
Various secondary batteries such as redox type batteries are used. First
The second batteries 46 and 47 may be, for example, 2 by connecting a plurality of secondary batteries in series or in series / parallel.
It is configured to have a voltage of 40 [V]. The first and second batteries 46 and 47 are connected to the voltage detection circuit 31 of the control unit 15 and their voltages are detected.

The hybrid power supply device 11 includes the first
And a fuel cell (F
C) 48 is provided. As the fuel cell 48, a phosphoric acid type or a methanol series type fuel cell is mainly used, but other types of fuel cells such as a molten carbonate type fuel cell and a solid electrolyte type fuel cell can also be used. is there.

The fuel cell 48 is connected to the anode side terminal of a diode 49 for preventing backflow, and is connected to the diode 49.
The cathode side terminal of is the switching terminal 511 of the first switch 51.
It is connected to the. Terminals 512 and 5 of the first switch 51
13 are terminals 522 and 52 of the second switch 52, respectively.
3 is connected to the first terminal between the terminals 512 and 522.
The anode side of the battery 46 is connected, and the terminals 513 and 5 are connected.
The anode side of the second battery 47 is connected between 23.
Both the cathode sides of the first and second batteries 46 and 47 are grounded to the main body of the electric vehicle. The switching terminal 521 of the second switch 52 is connected to the output terminal 12 of the hybrid power supply device 11. In this embodiment, the first and second switches 51 and 52 are composed of non-contact logic elements such as an AND element and an OR element. The connection directions of the first and second switches 51 and 52 are switched by a switching command signal S output from the control unit 15.

Next, the operation of the embodiment thus constructed will be described. Now, as shown in FIG. 2, the switching terminal 511 of the first switch 51 is connected to the terminal 512 side,
It is assumed that the switching terminal 521 of the second switch 52 is connected to the terminal 523 side. In this state, electric power is supplied to the control unit 15 of the electric vehicle from the second battery 47 via the second switch 52 and the output terminal 12.
The control unit 15 supplies the brushless DC motor 13 with electric power according to the output values of various sensors (not shown), or
The second battery 47 is regenerated. That is, the control unit 15
Supplies electric power from the second battery 47 to the brushless DC motor 13 during steady running and acceleration. The control unit 15 rectifies the electric power generated by the brushless DC motor 13 that functions as a generator and regenerates the second battery 47 during the regenerative operation by deceleration. On the other hand, the first battery 4
6 is charged by the fuel cell 48 via the first switch 51 and the diode 49.

Here, the voltage v1 of the first battery 46 being charged by the fuel cell 48 and the control unit 1
The voltage v2 of the second battery 47 supplying power to
Is continuously measured by the voltage detection circuit 31 of the control unit 15. The voltage detection circuit 31 supplies the measured voltage value signals v1 and v2 to the main computer 29. In the main computer 29, the supplied voltage value v
Starting and stopping the fuel cell 48 from 1, v2, and the first
And the connection of the second switches 51 and 52 is switched.

That is, the main computer 29 monitors the voltage value v2 of the battery on the side supplying power to the control unit 15, that is, the second battery 47 in the connected state shown in FIG. When the voltage value v2 becomes equal to or lower than the predetermined value, the remaining capacity of the second battery 47 is small, and it is determined that the subsequent discharge causes deterioration due to the overdischarge state. Output. The first and second switches 51 and 52 switch their connection by supplying the switching command signal S. When the switching signal S is supplied in the state shown in FIG. 2, the switching terminal 511 of the first switch 51 is switched from the connection with the terminal 512 to the connection with the terminal 513, and the switching terminal 521 of the second switch 52 is
The connection with the terminal 523 is switched to the connection with the terminal 522. As a result, the power supply source from the control unit 15 to the brushless DC motor 13 is the second battery 4 up to that point.
7 to the first battery 46. The second battery, which has a voltage equal to or lower than the predetermined value, receives the first switch 51
It is charged by the fuel cell 48 via.

On the other hand, when the voltage value v1 of the battery charged by the fuel cell 48, that is, the first battery 46 in the connected state shown in FIG. A stop signal (not shown) for instructing the stop is output. Fuel cell 4
In 8, when the stop signal is supplied, the activation is stopped.
As a result, overcharge of the first battery 46 is prevented. In this way, the first and second switches 51 and 52 are switched to supply electric power to the control unit 15 and charge the fuel cell 48 to the first and second batteries 46 and 46.
By alternating between 47, the maximum mileage of the electric vehicle can be extended.

In a system in which the traveling pattern changes intricately, starting, traveling and stopping are complicated. Since the fuel cell 48 has not yet reached the operating temperature of 180 ° C. at the very early start, the first battery 46 and the second battery 4 are mainly used.
Driven from both 7. The above-mentioned alternate switching may be performed after the operating condition is reached.

FIG. 3 shows the configuration of the second embodiment of the hybrid power supply device 11. This hybrid power supply device 11 can also be applied to an electric vehicle as in the case of the first embodiment. In this case, the drive control system shown in FIG. 1 can be used. In order to simplify the description of the following embodiment, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted as appropriate.

In the second embodiment, the first and second batteries 61 and 62, which are large-capacity capacitors (SC), are used in place of the first and second batteries 46 and 47 in the first embodiment. It is a thing. As the first and second capacitors 61 and 62, large-capacity capacitors having large capacitance per unit volume, such as electric double layer capacitors, and having low resistance and large output density are used. The capacities of the first and second capacitors 61 and 62 can be determined in consideration of the balance with the volume occupied by the first and second capacitors 61 and 62. In this embodiment, for example, a large-capacity capacitor of 9F or more is used. In addition, the first and second capacitors 61, 62
May have a configuration in which a plurality of capacitors are connected in series.
With this configuration, the withstand voltage of each capacitor can be set high.

Further, the capacitor has an advantage that the internal resistance is lower than that of the battery. Therefore, there is little loss,
It is possible to effectively use the large current drive at the time of starting and the large regenerative current from the brushless DC motor 13. When a capacitor is used, the load operating point for the fuel cell 48 changes, so it is difficult to operate under the maximum efficiency condition. However, in the conventional system shown in FIG. 7, compared with the load fluctuation due to direct driving from the fuel cell 5 to the motor 3, It becomes much easier to operate stably. In Equation 1, when Vc is the charging voltage of the capacitor, i is the charging current from the fuel cell 48, and C is the capacitor capacity, the relational expression of the capacitor is simply expressed as shown in the following Expression 1. Because it is done. Therefore, as compared with the case where the first and second batteries 46 and 47 in the first embodiment are used, it is possible to easily calculate how much the battery can be charged, and how much the vehicle can run with the remaining capacity. It becomes possible to easily predict whether or not.

[0022]

[Formula 1] Vc = (1 / C) ∫idt

Also in the second embodiment, the first switch 51 and the second switch 51 are operated similarly to the operation in the first embodiment.
By switching the switch 52, electric power is supplied to the control unit 15 from one of the first and second capacitors 61 and 62, and the other capacitor is charged by the fuel cell 48.

FIG. 4 shows the configuration of the third embodiment of the hybrid power supply device 11. This hybrid power supply device 11 can also be applied to an electric vehicle in the same manner as in the first embodiment to have the configuration of the drive control system shown in FIG. In the third embodiment, the first battery 46 in the first embodiment and the first capacitor 61 in the second embodiment are combined, and the second battery 47 and the second capacitor 62 are combined to make a hybrid power source. The device 11 is configured. In the third embodiment, the output of the hybrid power supply device 11 can be maintained at a constant voltage by the first and second batteries 46 and 47, so that the fuel cell 48 can be operated at the maximum efficiency point. . In addition, the first and second capacitors 61, 6
Since the internal resistance of No. 2 is extremely low, the internal loss is small and it is possible to endure rapid charge / discharge during driving and regeneration.

FIG. 5 shows the configuration of a fourth embodiment of the hybrid power supply device 11, which can be applied to an electric vehicle to provide the drive control system of FIG. In the fourth embodiment, in addition to the third embodiment, the fuel cell 48 directly drives the motor. Therefore, the first and second switches 51 and 52 are provided with the neutral terminals 514 and 524, and the third switch 63 is arranged. When power is supplied from the fuel cell 48 to the control unit 15, the switching terminal 511 of the first switch 51 and the switching terminal 521 of the second switch 52 are respectively connected to the neutral terminal 514 as shown in FIG. 5,
While connecting to the 24 side, the third switch 63 is set to the connected state. In this case, it is necessary to set conditions for ensuring the maximum efficiency of the fuel cell 48, and for that purpose, it is desirable that the rotation speed of the motor is constant, that is, the vehicle speed is constant. On the other hand, a combination of the first battery 46 and the first capacitor 61, or the second battery 47 and the second capacitor
When power is supplied to the control unit 15 by the combination of the capacitors 62, the third switch 63 is cut off. These first to third switches 51, 52, 63 are connected according to the switching signals S1 to S3 output from the control unit 15.

In the embodiment described above, the first, second and third switches 5 as the first connecting means and the second connecting means.
Although the elements 1, 52, and 63 are configured by non-contact logic elements, the present invention is not limited to these, and for example, members for various connections such as a contact relay circuit may be used. it can. Further, when the hybrid power supply device is used as a power supply other than an electric vehicle, various switches such as a snap switch can be used. Further, in the embodiment described above, two sets of power storage means such as a battery and a capacitor are used, but in the present invention, three or more sets of power storage means may be used. In this case, while the electric power is being supplied to the outside of the electric vehicle or the like by the electricity storage means connected to the output terminal by the first connection means, the connection of the second connection means is sequentially switched to another electricity storage means. Sequentially charge. The first connecting means selects the charged storage means and connects it to the output terminal.

[0027]

According to the hybrid power supply device of the present invention, it is possible to stably supply electric power.

[Brief description of drawings]

FIG. 1 is a diagram showing a drive control system of an electric vehicle using a hybrid power supply device according to an embodiment of the present invention.

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

FIG. 3 is a configuration diagram of a hybrid power supply device according to the second embodiment.

FIG. 4 is a configuration diagram of a hybrid power supply device according to the third embodiment.

FIG. 5 is a configuration diagram of a hybrid power supply device according to the fourth embodiment.

FIG. 6 is an explanatory diagram comparing output capacities and energy capacities of a storage battery and a fuel cell.

FIG. 7 is a schematic diagram of an electric vehicle equipped with a conventional hybrid power supply device.

[Explanation of symbols]

 11 Hybrid Power Supply 12 Output Terminal 13 Brushless DC Motor 20 Bridge Circuit 19 Current Waveform Control Circuit 28 Base Drive Circuit 29 Main Computer 31 Voltage Detection Circuit 46 First Battery 47 Second Battery 48 Fuel Cell 49 Diode 51 First Switch 52 Second Switch 61 First Capacitor 62 Second Capacitor 63 Third Switch

Claims (1)

[Claims] 1. An output terminal for supplying electric power to the outside, a plurality of power storage means for charging and discharging, a fuel cell for charging any of these power storage means, and one of the power storage means is selected. And first connecting means for connecting to the output terminal, and second connecting means for selecting any one of the power storage means not connected to the output terminal by the first connecting means and connecting to the fuel cell. A hybrid power supply device comprising: