JPH0998514A - Power unit for vehicle - Google Patents

Abstract

(57) Abstract: In a traveling state in which acceleration and deceleration are frequently repeated, a large-capacity capacitor is always sufficiently charged in preparation for the next acceleration, and energy regeneration efficiency is improved. SOLUTION: In a power supply device for a vehicle that regenerates braking energy of a vehicle driven by a motor 1 as an auxiliary energy or as an electric energy, a large-capacity capacitor 7 and a battery 8 connected in parallel to the motor 1 are provided. The large capacity capacitor 7 and the battery 8 are connected to the motor 1 independently of each other, and the breaker 6 capable of being cut off constitutes a power supply / charge circuit.

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 in an electric vehicle and a hybrid vehicle having a two-capacity power supply of a large capacity capacitor and a battery, and more particularly to improving energy regeneration efficiency and selecting and combining each power supply system. The present invention relates to a power supply device with improved flexibility.

[0002]

2. Description of the Related Art Generally, a power supply device for a vehicle such as an electric vehicle and a hybrid vehicle uses a three-phase AC motor as a generator, and is provided with an energy recovery system for recovering braking energy of the vehicle as electric energy into a battery. The recovered electrical energy is used to drive the vehicle. However, in the case of such a power supply device,
Not only a large battery capacity is required to supply electric power for acceleration, but also rapid charging / discharging during regeneration or running by a motor causes electrolysis in the battery to generate gas, which deteriorates the battery. Will be faster.

Therefore, in recent years, a large-capacity capacitor which can be rapidly charged / discharged without being chemically changed by charging / discharging is additionally arranged to a battery, and a large-capacity capacitor is mainly used for a large amount of electric power when running by a motor. Power supplies have been developed that are powered by.

As a prior art disclosing a vehicle power supply device using such a large-capacity capacitor, there is, for example, Japanese Patent Laid-Open No. 6-113407.

In this prior art, a large-capacity capacitor and a battery are connected in parallel to an inverter and a three-phase AC motor via a normally closed power supply circuit. The large-capacity capacitor and the battery are simultaneously connected in parallel to the inverter and the motor via the power feeding circuit and another regeneration circuit. In addition, the voltages of the large-capacity capacitor and the battery are set unequal,
Power is supplied to the motor from the large capacitor alone or from both the large capacitor and the battery. On the other hand, a step-up converter or a step-down converter is provided between the large-capacity capacitor in the regenerative circuit and the battery, so that the electric power generated by the motor during regeneration can be charged into the large-capacity capacitor and the battery at the same time. Charging of the large-capacity capacitor and the battery during regeneration is terminated by operating the chopper when the voltage of the large-capacity capacitor reaches a predetermined full charge voltage, and then the generated power is consumed as heat by the discharge resistance. .

[0006]

However, in such a conventional power supply device, since the battery and the large-capacity capacitor are charged at the same time during regeneration and the electric power generated by the motor is shared by both, the rapid charging of the large-capacity capacitor is hindered. Will end up. As a result, in the case of frequent acceleration and deceleration such as city driving and mountain driving, the large-capacity capacitor is not sufficiently charged during regeneration, and it does not function effectively during acceleration.

Further, when the voltage of the large-capacity capacitor reaches a predetermined full charge voltage, the charging of the battery together with the large-capacity capacitor is terminated, so that there is a problem that the regenerative energy is not efficiently utilized.

Further, since the large-capacity capacitor mainly supplies electric power to the motor during traveling by the motor, the electric power cannot be supplied only by the battery.

In view of the above circumstances, the present invention constantly charges a large-capacity capacitor rapidly so as to be able to cope with the next acceleration even in a situation where acceleration and deceleration are frequently repeated, such as driving in a city area or running on a mountain road. The purpose of the present invention is to improve the energy regeneration efficiency by making it possible to charge the battery after charging the capacitor. Furthermore, it is possible to freely set the power supply, such as driving the motor with one of the large-capacity capacitor and the battery, or driving the motor with a combination thereof, depending on the running state of the vehicle. .

[0010]

In order to solve the above-mentioned problems, the vehicle energy regenerative power supply device of the present invention regenerates the braking energy of the vehicle, which is driven by a motor as an electric energy, as an electric energy. In a vehicle power supply device, a circuit for both power supply and charging is configured from a large-capacity capacitor and a battery that are arranged in parallel with the motor, and a breaker that can connect and disconnect the large-capacity capacitor and the battery to the motor independently. .

When the vehicle is decelerating and energy is being regenerated, the breaker first connects only the high-capacity capacitor to the motor, which functions as a generator, and rapidly charges the high-capacity capacitor. Then, when the voltage on the bulk capacitor reaches the full charge voltage, the breaker switches to connect only the battery to the motor. As a result, the large-capacity capacitor is immediately charged, driving in urban areas,
The large-capacity capacitor can be sufficiently charged in preparation for the next acceleration even in situations where charging and discharging are frequently repeated, such as on mountain roads, and the braking energy during vehicle deceleration is efficiently charged to the large-capacity capacitor and battery. be able to. Further, during acceleration and steady running, by switching the breaker, electric power from the large-capacity capacitor and / or the battery can be selectively supplied to the motor, and the degree of freedom in combining the respective power supplies is improved.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system diagram showing an outline of a first embodiment in which a power supply device of the present invention is applied to a hybrid vehicle.

In FIG. 1, reference numeral 1 is a three-phase AC motor, which functions as an electric motor when the vehicle motor is running.
It functions as a generator when regenerating energy. Reference numeral 2 denotes an engine, and 3 denotes a transmission connected to the engine 2 via a clutch C2. The transmission 3 changes the engine speed and transmits power to the drive wheels 9 via the differential device 11. On the other hand, the motor 1 is connected to the differential device 11 and the drive wheels 9 via the clutch C1. Therefore, by controlling connection and disconnection of the clutches C1 and C2 in accordance with the running state of the vehicle or a manual request of the driver, both or one of the outputs of the motor 1 and the engine 2 is selectively driven. It is transmitted to the wheels 9. The vehicle drive modes include an engine drive mode in which the engine is driven alone, a motor drive mode in which the motor is driven alone, a combined drive mode in which the engine and motor are used in combination, and an energy regeneration drive mode during deceleration. An appropriate traveling mode is selected according to the traveling state of the vehicle during each of acceleration, steady state, and deceleration traveling.

Reference numeral E denotes a power supply device for the motor 1, which is composed of an inverter 4, an inverter control unit 5, a breaker 6, a large capacity capacitor 7 and a battery 8. The inverter 4 is composed of, for example, a three-phase bridge of a parallel circuit of a power MOS FET and a diode,
Are connected corresponding to each of the three-phase coils. The battery 8 is configured by connecting eight 12V single batteries in series. Large-capacity capacitor 7 and battery 8
Are connected in parallel to the motor 1 via the inverter 4 and the breaker 6, and the respective full charge voltages VFC and VFB are
Are preset so that VFC> VFB.
In the present embodiment, the full charge voltage VFB of the battery 8 =
For 96V (12V × 8), a large capacity capacitor 7 with VFC = 120V is adopted. On the other hand, the breaker 6 is composed of two sets of relays A and B, which are connected in series to a large-capacity capacitor 7 and a battery 8, respectively. The relays A and B are switches 61 and 63 and coils 62 and 64, respectively. It consists of a combination of.

Reference numeral 10 denotes a centralized control unit, which receives signals indicating a large capacity capacitor voltage VC, a battery voltage VB, a motor position P, an inverter current I, and other vehicle operating states including a brake switch, It sends an instruction signal to the control unit 5 and controls the operation of the breaker 6. In particular, the two sets of relays A and B of the breaker 6 are connected to the central control unit 10 as described later.
Therefore, the large-capacity capacitor 7 and the battery 8 can be simultaneously or selectively connected to the motor.

Next, the operation of the first embodiment of the present invention will be described with reference to the table of FIG.

First, at the time of acceleration or steady running of the vehicle, one of the engine running mode, the motor running mode, and the composite running mode is selected according to the running state of the vehicle or a manual request of the driver.

In the engine running mode, since it is not necessary to operate the motor 1, the clutch C1 between the motor 1 and the differential device 11 is disengaged, and further, both relays A and B of the breaker 6 are turned off. Power supply from the capacitor 7 and the battery 8 to the motor 1 is cut off.

In the motor drive mode, the clutch C2 between the engine 2 and the transmission 3 is disengaged and the clutch C1 between the motor 1 and the differential device 11 is engaged. Further, the relays A and B of the breaker 6 are selectively connected according to the magnitudes of the voltage VC of the large-capacity capacitor 7 and the voltage VB of the battery 8 to control the power supply to the motor 1. Basically, when a large motor output is required at the time of starting or accelerating the vehicle, the electric power regenerated at the time of deceleration immediately before acceleration and stored in the large capacity capacitor 7 is supplied to the motor 1 or the large capacity capacitor is supplied. The breaker control logic is set so that power is supplied from both the battery 7 and the battery 8 and then the battery 8 alone supplies power when shifting to steady operation. Therefore, vehicle acceleration →
The breaker control logic described above is repeatedly executed in each cycle of steady-state → deceleration → acceleration. As described above, since the electric power stored in the large-capacity capacitor 7 is preferentially used to drive the motor 1, the battery 8
The power supply opportunity due to is reduced, and the life deterioration of the battery can be suppressed accordingly.

The table of FIG. 2 shows an example of breaker control logic. As will be described later, according to the present invention, since the large-capacity capacitor 7 is sufficiently charged during deceleration, VC> VB during acceleration, and only the relay A corresponding to the large-capacity capacitor 7 is turned on and the large-capacity capacitor 7 is turned on. Power is supplied to the motor 1. Also, the electric power of the large-capacity capacitor 7 is consumed, and VC ≤ VB (where VB>
VEB; when VEB becomes a predetermined minimum battery voltage), the relay A is turned off, the relay B corresponding to the battery 8 is turned on, and power is supplied from only the battery 8 to the motor 1. The voltage VC of the large-capacity capacitor 7 is VC
Since the discharge time until ≦ VB is set longer than the time required for normal acceleration, within the discharge time, the acceleration is shifted to the steady running state without damaging the acceleration feeling. On the other hand, when a high output is required for the motor 1 such as during rapid acceleration, both the relay A and the relay B are turned on and both the large-capacitance capacitor 7 and the battery 8 turn on the motor 1 as long as VC ≧ VB> VEB. Is powered.

As described above, normally, when VC> VB, the relay B is turned off to shut off the current flow from the large capacity capacitor 7 to the battery 8.
The continuous application of overvoltage is prevented. Further, when VC≤VB, the relay A is turned off to interrupt the discharge of the large current from the battery 8 to the large capacity capacitor 7, so that the rapid deterioration of the battery is prevented. In this way, the breaker 6 also functions as a fail-safe mechanism when the voltages of both power sources are unbalanced.

Next, in the combined driving mode of the motor 1 and the engine 2, the clutches C1 and C2 provided between the motor 1 and the differential device 11 and between the engine 2 and the transmission 3 are engaged and the motor is driven. The vehicle is driven by the sum of the outputs of 1 and the engine 2. The power supply to the motor 1 in this mode is controlled in the same manner as in the motor running mode described above.

On the other hand, when the driver depresses the brake pedal to turn on a brake switch (not shown), the energy regeneration running mode for decelerating the vehicle is executed. In this case, the motor 1 is connected to the differential device 11 by engaging the clutch C1, and receives braking energy from the wheels to generate electric power. When the large-capacity capacitor voltage VC does not reach the full charge voltage VFC when the energy regeneration running mode is started (VC <VFC), first, only the relay A of the breaker 6 is turned on and the electric power generated by the motor 1 is generated. Is supplied only to the large-capacity capacitor 7. As a result, the large-capacity capacitor 7 is charged rapidly and is always set to the full charge state in preparation for the next acceleration even during traveling in which acceleration and deceleration are frequently performed. When the capacitor voltage VC reaches the full charge voltage VFC (VC>
VFC), the relay A of the breaker 6 is turned off to stop the charging of the large-capacity capacitor 7, and then the relay B is turned on to charge the battery 8. However, the battery 8 is charged only when the battery voltage VB has not reached the full charge voltage VFB. Normally, the braking time is relatively short,
Since the battery 8 is not charged at the time of regeneration or for an extremely short time, electrolysis in the battery 8 due to long-time rapid charging does not occur, and therefore gas is generated and the battery 8 is not charged. Does not cause deterioration of. Further, when both the large-capacity capacitor voltage VC and the battery voltage VB reach the full charge voltage, the relays A and B are
Both are turned off and the regeneration is terminated. At this time, the clutch C1 between the motor 1 and the differential device 11 is also released, so that the power generation of the motor 1 is stopped.

FIGS. 3 and 4 show a second embodiment of the present invention, and particularly show the case where the present invention is applied to an electric vehicle. The same components as those in the first embodiment are designated by the same reference numerals.

The structural difference between the second embodiment and the first embodiment is that the engine 2 and the transmission 3 and the clutch C2 between them are eliminated in order to correspond to the electric vehicle. Only. Therefore, the traveling modes of the vehicle are only the motor traveling mode during acceleration and steady traveling, and the energy regeneration traveling mode during deceleration. However, the control logic of the breaker 6 in the motor traveling mode and the energy regeneration traveling mode is the same as the logic in the corresponding mode of the first embodiment.

Although the embodiment of the present invention has been described in detail above, the present invention is not limited to this.
In the case of hybrid vehicles, the clutch between the motor and the differential device is engaged while the vehicle is driven by the engine output so that the motor functions as a generator, and the charging traveling mode in which the engine travels while charging the large-capacity capacitor and the battery is added. Good.

Further, in the above-described embodiment, when both the large-capacity capacitor and the battery reach the full charge voltage during regeneration, the clutch is turned off so that the motor is not operated, but the clutch is not provided. In the case of a vehicle, a chopper may be provided so that the generated power is consumed as heat via the discharge resistance.

Furthermore, the breaker control logic is not limited to the one described above, but can be arbitrarily designed so as to correspond to the output characteristics required in each running condition.

According to the first aspect of the present invention, when energy is regenerated while the vehicle is decelerating, first of all, only the large-capacity capacitor is rapidly charged. Even when charging and discharging are frequently repeated, the large-capacity capacitor can be sufficiently charged in preparation for the next acceleration. Further, since the battery is charged after the voltage of the large capacity capacitor during charging reaches the full charge voltage, it is possible to efficiently charge the large capacity capacitor and the battery with braking energy during vehicle deceleration. Further, electric power from both or one of the large-capacity capacitor and the battery can be selectively supplied to the motor during acceleration and steady running, and the degree of freedom in combination of the respective power sources is improved.

[Brief description of drawings]

FIG. 1 is a system diagram showing a power supply device for a hybrid vehicle according to a first embodiment.

FIG. 2 is a table for explaining the operation of the power supply device according to the first embodiment.

FIG. 3 is a system diagram showing a power supply device for an electric vehicle according to a second embodiment.

FIG. 4 is a table for explaining the operation of the power supply device according to the second embodiment.

[Explanation of symbols] 1 motor 4 inverter 6 breaker 7 large capacity capacitor 8 battery 10 centralized control unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kuniaki Emura 1-7-2 Nishishinjuku, Shinjuku-ku, Tokyo Inside Fuji Heavy Industries Ltd.

Claims (2)

[Claims] 1. A large-capacity capacitor and a battery that are arranged in parallel with a motor in a vehicle power supply device that regenerates the braking energy of a vehicle that is driven by a motor as a supplementary or main constituent as electric energy.
A vehicle power supply device characterized in that a circuit for supplying and charging electricity is configured from a breaker that can independently connect and disconnect a large-capacity capacitor and a battery to a motor. 2. The power supply device for a vehicle according to claim 1, wherein the breaker comprises two sets of relays corresponding to the large capacity capacitor and the battery, respectively.