JPH06197408A - Storage battery controller for electric vehicle - Google Patents

Abstract

PURPOSE:To use in combination a continuous storage battery and an instantaneous storage battery. CONSTITUTION:Transistors Ca1, Ca1 are connected between a continuous storage battery 1 and a motor 3, transistors Cb1, Cb2 are connected between an instantaneous storage battery 2 and the motor 3, and the transistors Ca1, Cb1 are alternately turned ON, OFF at the time of discharging, and the transistors Ca2, Cb2 are alternately turned ON, OFF at the time of charging by a duty ratio set corresponding to required charge/discharge current flow rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a storage battery used in an electric vehicle, and more particularly to a combination of a low-current / long-time type persistent storage battery and a high-current / short-time type instantaneous storage battery. Related to technology used in automobiles.

[0002]

2. Description of the Related Art In recent years, in order to save fuel consumption and improve air pollution and noise problems due to combustion exhaust gas, an electric vehicle using an induction motor as a prime mover or a prime mover combining an internal combustion engine and the induction motor is used. Scheme electric vehicles have been developed. The storage battery mounted as a power source for this electric vehicle is classified into two types, a continuous battery and a flash battery, depending on the structure, the material of the electrode plate, the properties of the electrolyte, etc. Be separated. Lead storage batteries are representative of persistent storage batteries, and nickel and cadmium storage batteries are representative of instantaneous storage batteries.

A long-lasting battery can be discharged for a long time at the time of discharging, but has a characteristic that the discharging current is relatively small and a large current cannot be discharged at one time, and the charging current is generally small at the time of charging. It is a small current, long time type storage battery that is required to be operated for a long time with electric current. On the other hand, the instantaneous battery is a large-current / short-time type storage battery which has a characteristic that it can discharge a large current at one time and can be rapidly charged with a large current even during charging.

The performance required as a storage battery to be mounted on an electric vehicle is that it is possible to increase the acceleration ability and ensure the climbing ability and can be charged in a short time. Is desirable.

[0005]

However, although the persistent storage battery has a mass production / collection system established and is inexpensive, many instantaneous storage batteries use nickel, cobalt, silver, etc. and are expensive. However, it is hard to say that a safe and inexpensive recovery method has been established, and it is difficult to use only the instantaneous storage battery for an electric vehicle.

On the other hand, in terms of performance, in an electric vehicle equipped with a composite prime mover composed of an internal combustion engine and an electric motor, in the case of long-distance running, the internal combustion engine is not dependent on only the storage battery for supplying energy for long-distance running. It runs to make up for the lack of power, so a certain level of sustainability is sufficient. Also, in order to secure acceleration performance and climbing performance, a large current is required within a short time, but the internal combustion engine can be energized when a large current is required for climbing, high-speed running, and intense acceleration, The performance required for a storage battery of an electric vehicle, which is capable of charging / discharging with a large current and in a short time, is considerably relaxed. Furthermore, when the stored power of the storage battery becomes insufficient, the storage battery can be charged even while the internal combustion engine is running, so that charging in a short time is not an essential condition. Therefore, it is possible to use a persistent storage battery in an electric vehicle, and if an inexpensive persistent storage battery and a large-current / short-time instantaneous storage battery can be used in combination, it is an optimal power source for an electric vehicle. Becomes

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a storage battery control device for an electric vehicle that can be used in combination with a persistent storage battery and an instantaneous storage battery. .

[0008]

Therefore, the present invention provides a persistent storage battery that has a small charge / discharge current amount and is charged / discharged for a long time, and an instantaneous storage battery that can be charged / discharged with a large current amount at a time. While connected to a common power generation source and load via a charging circuit and a discharging circuit, respectively, a current detection means for detecting a required charging / discharging current amount of the persistent storage battery or the instantaneous storage battery, and the required charging / discharging current amount is small. A control means is provided so that the current sharing ratio of the persistent storage battery is increased at times, and the current sharing ratio of the instantaneous storage battery is increased when the required charge / discharge current amount is large.

Further, a switch means is provided in each of the charging circuit and the discharging circuit of each of the storage batteries, and the control means is switched so that one of the switch means for each of the storage batteries is turned on, and the demand is satisfied. The current sharing ratio is controlled by variably controlling the time ratio of the ON time of each switch according to the discharge current amount.

[0010]

According to the above construction, the required charge / discharge current amount of the persistent storage battery or the instantaneous storage battery is detected by the current detecting means at the time of charging / discharging, and the current sharing ratio of the persistent storage battery and the instantaneous storage battery is the required charging / discharging ratio. It is controlled by the control means based on the discharge current amount. That is, when the required charge / discharge current amount is small, the current sharing ratio of the persistent storage battery is controlled to be large, and when the required charge / discharge current amount is large, the current sharing ratio of the instantaneous storage battery is controlled to be large. ,
Both storage batteries can be combined and installed in an electric vehicle.

Further, the control means controls one of the switch means for each storage battery to be turned on in accordance with the required charge / discharge current amount, thereby varying the time ratio and adjusting the current sharing ratio well. Is possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a storage battery control device for an electric vehicle of this embodiment, and this system is provided in, for example, an electric vehicle of a combined prime mover system. In FIG. 1, a persistent storage battery 1
Is a low-current / long-time type storage battery that is required to be discharged for a long time with a relatively small current amount during discharging, and is generally required to be charged for a long time with a small current amount during charging.
For example, a lead storage battery is used. Also, the instantaneous storage battery 2
Has the characteristic of being able to discharge a large amount of current at one time, and it is also capable of performing rapid charging with a large amount of current during charging.
It is a short-time storage battery, and for example, a nickel-cadmium storage battery or the like is used. The electric motor 3 can be both a load and a power source.

The discharge circuit between the persistent storage battery 1 and the electric motor 3 is constructed by connecting the backflow prevention diode Da1, the PNP transistor Ca1 and the current sensor 4 as current detecting means in this order from the persistent storage battery 1. The charging circuit is configured by sequentially connecting the current sensor 4, the PNP transistor Ca2, and the backflow prevention diode Da2 from the electric motor 3.

Similarly, the discharge circuit between the instantaneous storage battery 2 and the electric motor 3 is constructed by connecting the reverse current prevention diode Db1, the PNP transistor Cb1, and the current sensor 4 in order from the instantaneous storage battery 2 to charge the battery. The circuit is
A current sensor 4, a PNP transistor Cb2, and a backflow prevention diode Db2 are sequentially connected from the electric motor 3. The transistors Ca1 and Ca
2, Cb1 and Cb2 are fast switching elements, and the current sensor 4 is not only capable of detecting the amount of charge / discharge current but also capable of detecting the current direction so that charge / discharge can be discriminated. .

The transistors Ca1, Ca2, Cb
1, Cb2 correspond to the switch means. The power supply control device 5 as a control means includes an A / D converter 6, a non-volatile memory 7, and a microcomputer 8, and is connected to the bases of the respective transistors. In addition, the power supply control device 5 receives a Start-acknowledge signal from the integrated control devices of the electric vehicles arranged in parallel, which is a signal indicating completion of activation of the integrated control devices.
A legde (hereinafter abbreviated as St-akn) signal is transmitted, and the power supply control device 5 starts control after receiving this St-akn signal. Before receiving the St-akn signal, depending on the type of semiconductor device used in the integrated control device, it may be damaged if power is supplied before activation. Therefore, the transistors Ca1, Ca2,
All of Cb1 and Cb2 are kept in a state of cutting off the current. Further, the consumption current value detected by the current sensor 4 is used as the required charging / discharging current value and the A / D converter 6 of the power supply controller 5
Entered in. The A / D converter 6 digitizes the input charge / discharge current value. In the non-volatile memory 7, the time ratio of the on time for each transistor corresponding to the required charge / discharge current value of the electric motor 3 is preset and stored as the duty ratio (FIG. 4) of the on time of the instantaneous storage battery 2. . The microcomputer 8 contains software that controls each transistor based on the required charging / discharging current value.

Next, the processing of the power supply controller 5 will be described with reference to the flowchart of FIG. In step (denoted as "S" in the drawing, the same applies hereinafter) 1, the process waits until the St-akn signal is received from the integrated control device, the start switch, or the like. As described above, before receiving the St-akn signal, each of the transistors Ca1, Ca2, Cb1 and Cb2 is kept in a state of cutting off the current. When the St-akn signal is received, the process proceeds to step 2.

Step 2 is an operation chart shown in FIG.
As shown in (B), an ON signal is output to the base of either or both of the transistors Ca1 and Cb1 to change both of the transistors Ca1 and Cb1 from the cut-off state to the conduction state, and charge and discharge are performed in the small current mode. . This makes it possible to determine the energizing direction. In step 3, the charge current or discharge current value detected by the current sensor 4 is input,
Based on the current detection signal digitized by the A / D converter 6, it is determined whether the persistent storage battery 1 is in the charging state or the discharging state. If the electric motor 3 is a load circuit, the persistent storage battery 1 is discharged and the energizing direction is the electric motor 3 direction. If the electric motor 3 is a power generating circuit, the persistent storage battery 1 is charged and the energizing direction is continuous. It is one direction of the sex storage battery.

When starting from step 2 to step 3, the vehicle is naturally in the discharged state, and when it is in the discharged state, the procedure proceeds to step 4 and thereafter. In step 4, the required discharge current value is input from the current sensor 4. In step 5, with reference to the graph of FIG. 4 stored in the non-volatile memory 7, the conduction period of each of the transistors Ca1 and Cb1 based on the required discharge current value, that is, the on-time ratio is determined. Here, it can be controlled by increasing (decreasing) the on-time ratio of the transistor Cb1 on the side of the instantaneous storage battery 2 to increase (decrease) the amount of charge / discharge current. The timing of the switching operation is a continuous power feeding method in which one of the transistors Ca1 and Cb1 is turned on while the other is turned off in order to smooth the output current and obtain a good result. Further, when the current sensor 4 is installed for each bank of the persistent storage battery 1 and the instantaneous storage battery 2, the nonvolatile memory 7
The respective allowable values of the charging / discharging currents are stored in, and the signals from the respective sensors are compared with the allowable values of the charging / discharging currents for calculation.

For example, when traveling for an extremely long distance, the persistent storage battery 1
Alternatively, rather than relying only on the instantaneous storage battery 2 to supply energy for long-distance traveling, the internal combustion engine is operated to compensate for the lack of electric power, so a sufficient sustainability is sufficient, and the required discharge current amount is small. In that case, the on period of the transistor Ca1 on the side of the persistent storage battery 1 is lengthened, and the on period of the transistor Cb1 on the side of the instantaneous storage battery 2 is shortened. Specifically, as shown in the small current mode of FIG. 3B, for example, assuming that the number of clocks in one cycle determined in consideration of the performance of the high speed switching element is 100, the transistor C
The conduction periods of a1 and Cb1 are 80 and 20 clocks, respectively.
It should be noted that, when the current is still smaller, the minimum current mode (A) may be set to make the transistor Ca1 conductive and keep the transistor Cb1 in the cutoff state.

Further, for example, when climbing or accelerating, a medium to relatively large current is required, and the transistors Ca1 and Cb1 are required.
Situation in which the clock periods of the above are substantially equalized, for example, FIG. 3 (C)
As shown in, the duty ratio is controlled to be 50 clocks. Further, the clock period for conduction is adjusted by the discharge current so that the discharge limit of the persistent storage battery 1 and the discharge limit of the instantaneous storage battery 2 are not exceeded.

Further, when the discharge current becomes a large current, as shown in the large current mode of FIG. 3D, the number of conduction clocks of the transistor Cb1 on the side of the instantaneous storage battery 2 is large and the sustainability is high until the normal operating limit. Transistor Ca of storage battery 1
The number of conduction clocks of 1 is controlled to be small. Even in this case, while controlling so as not to exceed the respective discharge limit currents, control is performed so that the share of the instantaneous storage battery 2 increases as the currents increase.

However, although it is not a recommended usage as a characteristic of the storage battery, for example, when performing "overtaking" or "merging on an expressway" in an electric vehicle, a special large period is required for several seconds to several tens of seconds. May require current. Also, for example, in the case of an ordinary automobile equipped with an internal combustion engine, when energizing the starter motor when starting the engine,
The required energization amount far exceeds the allowable discharge current of the instantaneous storage battery 2. In such a case, it is necessary to discharge beyond the normal discharge limit current, but the time is usually short. Therefore, for a short time, the transistor Cb1 is allowed to conduct only in an emergency evacuation within a range in which the use frequency and the use time do not adversely affect the durability of the instantaneous storage battery 2. Further, for example, as shown in the maximum current mode of FIG. 3 (E), the persistent storage battery 1 and the instantaneous storage battery 2 may be overlapped, or both may be continuously used.

In step 6, the transistor C is set based on the duty ratio of the ON time set as described above.
ON / OFF control of a1 and Cb1. Next, when the electric motor 3 functions as a generator during braking, it is determined in step 3 that the battery is in a charged state, the process proceeds to step 7, and the required charging current value from the current sensor 4 is input in the same manner as during discharging, Each transistor Ca based on the required charging current value in 8
2. Determine the conduction period of Cb2. The continuous charging method is used for charging as well as discharging, and the current sensor 4 is used for the persistent storage battery 1.
When the flash storage battery 2 is installed in each bank, the charge / discharge current is calculated in comparison with the allowable value so that the allowable value is not exceeded. Then, in step 9, the transistor C
ON / OFF control of a2 and Cb2.

When the St-akn signal is stopped, step 10
Then, the stop of the St-akn signal is detected, and this routine ends. According to this configuration, the duty ratio of the persistent storage battery 1 and the instantaneous storage battery 2 is set based on the required charge / discharge current value, and the transistor Ca1,
Since Ca2, Cb1, and Cb2 are controlled to be turned on / off, the charge / discharge current amount can be optimized for the performance of the storage battery, and by using such a combination, high-speed running performance that requires a large current, It has good acceleration performance, climbing performance, etc., sufficient sustainability can be obtained even during extremely long distance runs, and quick charging with a large current is also possible.
It is possible to make a power supply system suitable for future electric vehicles in terms of cost, etc.

This system can also be applied to a hybrid prime mover type electric vehicle equipped with an internal combustion engine and an electric motor. In that case, the storage battery can be charged from a separately provided power generation circuit other than during braking. Other systems include electric vehicles with electric motors only,
It is also effective for electric forklifts and other devices that use a storage battery as a power source.

[0026]

As described above, according to the present invention, both storage batteries are controlled by controlling the current sharing ratio of the persistent storage battery and the instantaneous storage battery according to the required charge / discharge current amount detected by the current detection means. Can be combined with each other to charge and discharge with an optimum amount of charge and discharge current for each storage battery. In addition, by using both storage batteries in combination, the high current running performance, acceleration performance, and climbing performance that require a large current are good, and sufficient sustainability can be obtained even at extremely long distances. Rapid charging is also possible, making it a power supply system suitable for electric vehicles.

Further, by switching one of the switch means interposed in the charging circuit and the discharging circuit of each storage battery to be turned on and making the time ratio of the on time variable, the current sharing ratio is adjusted well. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of FIG.

FIG. 3 is an operation chart of the high speed switching element of FIG.

FIG. 4 is a relational diagram stored in the nonvolatile memory of FIG. 1.

[Explanation of symbols]

 1 Sustainable storage battery 2 Instantaneous storage battery 3 Electric motor 4 Current sensor 5 Power supply control device 6 A / D converter 7 Non-volatile memory 8 Micro computer

Claims (2)

[Claims] 1. A continuous storage battery, which has a small amount of charge / discharge current and is charged / discharged for a long time, and an instantaneous storage battery, which can be charged / discharged with a large amount of current at one time, are commonly provided via a charging circuit and a discharging circuit, respectively. Current detecting means for detecting the required charging / discharging current amount of the persistent storage battery or the instantaneous storage battery while being connected to the power generation source and the load, and the current sharing ratio of the persistent storage battery when the required charging / discharging current amount is small. A storage battery control device for an electric vehicle, comprising: a control unit that controls to increase, and a control unit that controls to increase the current sharing ratio of the instantaneous storage battery when the required charging / discharging current amount is large. 2. A charging circuit and a discharging circuit of each of the storage batteries are respectively provided with switch means, and the control means is switched so that one of the switch means for each of the storage batteries is turned on, and the required charge is satisfied. 2. The storage battery control device for an electric vehicle according to claim 1, wherein the current sharing ratio is controlled by variably controlling the time ratio of the ON time of each switch according to the discharge current amount.