JPH07131905A - Hybrid power source for electric vehicle - Google Patents

Abstract

PURPOSE:To improve an energy efficiency by effectively utilizing regenerated power. CONSTITUTION:A hybrid power source for a motor operated vehicle charges a battery by operating an engine generator 8 when it needs recharging, and forcibly rotates an engine 7 during stopping by supplying regenerated power to the generator 8 used also as a motor to be used as a brake load. After a regenerative brake of a traveling motor 3 is released, the generator 8 is operated as a generator with rotating inertial energy of the forcible rotation to supply the generated power to a battery 1, thereby providing the hybrid power source for the vehicle.

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 supplying electric power to an electric motor in an electric vehicle which is driven by driving the electric motor.

[0002]

2. Description of the Related Art In recent years, electric running vehicles that are pollution-free and noise-free and easy to operate are attracting attention and are being put into practical use.
The biggest problem of the electric traveling vehicle is that the battery that stores the electric power supplied to the electric motor has a large capacity and a large number of batteries must be mounted in order to extend the travelable distance in one battery charging.

Therefore, as described in, for example, Japanese Patent Application Laid-Open No. 55-157901, an electric power traveling vehicle has been proposed which is provided with a so-called hybrid power supply device equipped with an engine generator that automatically operates according to the state of charge of a battery. .

By the way, in this kind of electric traveling vehicle, regenerative braking for converting the braking force of the vehicle into electric energy to charge the battery is widely performed by operating the traveling electric motor as a generator during braking operation. (For example, JP-A-62-104403).

[0005]

[Problems to be Solved] However, while this regenerative power becomes considerably large, the charging allowable current of the battery is limited, so it is never preferable to charge the battery by overcurrent, and the regenerative power is not sufficient for the battery. I can't absorb enough.

Therefore, the amount of the regenerated electric power that cannot be absorbed is consumed as heat by a resistive load that consumes a large amount of electric power, or the mechanical brake is made heavy so that the regenerated electric power is limited to the allowable range for charging the battery. I had no choice but to adopt such a method.

The present invention has been made in view of the above point, and the object thereof is to forcibly rotate and drive the engine in a stopped state by regenerative power surplus other than battery charging, thereby increasing the rotational inertia of the engine. The point is to provide a hybrid power supply device for an electric vehicle that absorbs regenerative electric power energy by utilizing it and further extracts a part of the energy absorbed by this rotational inertia for battery charging again to improve energy efficiency. It is in.

[0008]

To achieve the above object, the present invention provides a battery for driving a traveling electric motor which is a traveling drive source, and an engine-driven generator for supplying electric power to the battery. In the hybrid power supply device for an electrically driven vehicle configured to drive the engine generator when the remaining battery level is low to supplement the battery shortage, the engine-driven generator includes an engine and the engine Inside is a generator driven by an engine, and at the time of starting the engine, a generator that also serves as an electric motor for starting the engine is provided, and at the time of regenerative braking of the traveling electric motor, the regenerative electric power is used as charging power. By supplying the regenerative power to the generator that also serves as the electric motor while supplying the battery,
A hybrid power supply device for an electrically driven vehicle configured to forcibly rotate the stopped engine and use it as a brake load.

Since the regenerative electric power from the running electric motor is supplied to the battery while being supplied to the electric motor / generator to forcibly rotate the stopped engine, the inertial force of the rotation at the time of starting the engine is used as a load. Braking is possible, and the load on the mechanical brake can be significantly reduced while limiting the charging current to the battery to an allowable value.

Further, after the regenerative braking of the traveling electric motor is released, the generator that also serves as the electric motor is operated as a generator by the rotational inertia energy of the forced rotation so that the generated electric power is supplied to the battery. Since the configuration is adopted, after regenerative braking, the generator can be operated by the rotational inertia energy to charge the battery, and the energy efficiency of the engine can be improved. In particular, it excels in energy efficiency when driving in urban areas where acceleration and deceleration are often repeated.

[0011]

EXAMPLE An example of the present invention shown in FIGS. 1 and 2 will be described below. FIG. 1 is a schematic configuration diagram of a hybrid power supply device for an electrically driven vehicle according to the present embodiment.

The engine generator 6 of this embodiment is composed of an engine 7 and a generator 8 which also serves as an electric motor and which includes an outer rotor type magnet rotor (not shown) directly connected to the crankshaft of the engine 7. The generator 8 which also serves as an electric motor operates as a generator by the driving force of the engine 7 and supplies electric power to the main battery 1, while the electric power supplied from the main battery 1 operates as an electric motor to start the engine 7. it can. Since the engine 7 and the generator 8 are directly connected, there is no gear noise at the time of starting.

The main battery 1 serving as a power source is constructed so that an on-vehicle charger (not shown) can perform a normal charging operation through an external power source connection terminal (not shown) such as a charging station. The output of the main battery 1 is controlled by the drive controller 2 which is an inverter circuit and supplied to the drive motor 3, whereby the drive motor 3 is drive-controlled and the vehicle travels.

The engine generator 6 is incorporated as a self-charging mechanism, and the generator 8 generates power when the engine 7 is driven, and its three-phase power is an inverter unit.
The main battery 1 is full-wave rectified and summed by the rectifier circuit 9 composed of flywheel diodes in 20.
Is configured to be supplied to.

Further, as described above, the generator 8 is configured as a generator that also serves as an electric motor. Conversely, the electric power of the main battery 1 is supplied to the generator 8 through the inverter 5 in the inverter unit 20 to serve as an electric motor. By driving, the engine 7 can be made to function as a starter motor for starting the engine 7.

That is, normally, as described above, the main battery 1 is charged by the external electric power, but in an emergency where the electric power cannot be obtained from the outside, it is possible that the remaining battery capacity of the main battery 1 has dropped to a predetermined value or less. Upon detection, the engine start signal 4 gives an instruction to the inverter circuit 5 of the inverter unit 20 to control the duty and gradually increase the supply voltage of the main battery 1 to supply power to the generator 8 of the engine-driven generator 6 which also serves as a motor. Then, it is driven as an electric motor to start the engine 7.

When the engine 7 operates, the generator 8 works as an original generator, and the generated power is rectified by the rectifier circuit 9 of the inverter unit 20 and supplied to the main battery 1 to weaken the main battery 1. To charge.

As described above, normally, the traveling motor 3 is driven only by the charging energy of the main battery 1 to drive the vehicle, and the generator 8 is driven as an electric motor only in an emergency when the remaining battery level drops below a predetermined value. Then, the engine 7 is started, and while the engine 7 is in operation, it is charged by the electric power generated by the generator 8.

On the other hand, during deceleration during traveling when the remaining energy of the main battery 1 is sufficient, the rotational energy stored in the inertia of the traveling motor 3 and the load is regeneratively braked via the regenerative braking controller 10. . That is, the traveling motor 3 performs a power generation operation, and the generated power is supplied to the main battery 1 via the regenerative braking controller 10 to be charged.

The regenerative braking controller 10 is a step-up DC
A DC converter is provided, the regenerative electric power of the traveling motor 3 is boosted and supplied to the main battery 1, and in the present application, the generator 8 is further provided via the inverter circuit 5.
The engine 7 is driven by the generator 8 as an electric motor and is stopped, and the engine 7 is forcibly rotated without being accompanied by an ignition operation so that the engine brake is applied with the engine as a load.

The above-described control by the traveling controller 2 and the regenerative braking controller 10 is performed based on the accelerator position detection signal 11 and the brake operation detection signal 12. The accelerator position detection signal 11 indicates whether the accelerator is in the depressed state or in the released state. With each detection signal whether it is in or there is no change in position,
It is inputted to the traveling controller 2 and the regenerative braking controller 10, while the brake operation detection signal 12 is inputted to the regenerative braking controller 10 as a detection signal indicating whether or not the brake is in operation.

The state of charging / discharging the main battery 1 during actual traveling will be described below with reference to FIG. 2 (a). First, when the accelerator is stepped on and the accelerator position detection signal 11 outputs a stepping signal to the traveling controller 2, the traveling controller 2 controls the duty according to the stepping speed to supply electric power from the main battery 1 to the traveling motor 3. To accelerate. The amount of discharge of the main battery 1 is large for acceleration at the start of running.

When the accelerator position is determined and the vehicle starts traveling at a constant speed, the discharge amount of the main battery 1 is small and controlled to a predetermined amount.

When the accelerator is released and the accelerator return signal enters the traveling controller 2, the discharge of the main battery 1 is stopped, while the accelerator return signal is input to the regenerative braking controller 10 to drive the traveling motor 3. The regenerative power is boosted and used to charge the main battery 1. Since the main battery 1 has the charge allowable level, the main battery 1 is charged at the same level.

When the brake is stepped on here, the brake operation detection signal 12 is input to the regenerative braking controller 10, and the regenerative braking controller 10 continues charging the main battery 1 at the charge allowable level while the traveling motor 3 is driven. The regenerative power is further boosted, and the regenerative power boosted beyond the charge allowable level of the main battery 1 is output to the inverter circuit 5 without passing through the main battery 1.

Then, the inverter circuit 5 operates to supply the regenerative electric power of the traveling motor 3 rapidly increased by the braking operation to the generator 8 to drive the generator 8 as an electric motor to rotate the stopped engine. By increasing the voltage supplied to the generator 8 by the regenerative braking controller 10,
With respect to the rotational speed during braking, a rotational speed higher than that during normal power generation is possible, and the maximum energy that can be absorbed is increased.

As described above, the generator (electric motor) 8 is driven by a large amount of regenerative electric power that cannot be absorbed by battery charging, and it is made to act as an engine brake with the engine as a load, and is used as a substitute for the conventional resistor for power consumption. . The shaded area in the braking process in Fig. 2 (a) is the regenerative power absorbed by the engine brake.

With this surplus regenerated electric power, a generator (electric motor) 8
When the engine is driven and the engine 7 rotates, the engine speed increases as shown in FIG. 2 (b).

When the brake is released and the accelerator is stepped on to accelerate again, the regenerative braking controller 10 and the inverter circuit 5 stop operating and the traveling controller 2 operates, so that the discharge power of the main battery 1 passes through the traveling controller 2. It is supplied to the traveling motor 3.

At this time, the engine 7 and the generator 8 continue to rotate due to inertial force, and the generator 8 can generate electric power due to the rotational inertia so that the main battery 1 can be charged through the rectifying circuit 9 to run. Of the amount of electric discharge to the motor 3 (Fig. 2
It is possible to supplement the part (a) of the re-acceleration process). Note that in FIG. 2 (a), since the vehicle is already in a traveling state, the amount of discharge at re-acceleration is smaller than at the start of traveling.

Regarding this inertial power generation, as the rotating mass of the generator 8 is larger, the lowering speed of the engine speed is suppressed and the charging time becomes longer. Then, as shown in FIG. 2 (a), when the vehicle starts to run at a constant speed, the discharge amount of the main battery 1 is further reduced.

As described above, during the regenerative braking of the traveling motor 3, the regenerative electric power is used for charging the main battery 1, and the generator 8 is driven as an electric motor to forcibly rotate the stopped engine 7. The engine brake can be operated by using the engine as a load, and after regenerative braking, charging can be performed by the rotational inertia energy of the generator 8, so that energy efficiency can be improved.

In particular, it is possible to improve energy efficiency when traveling repeatedly with acceleration and deceleration, for example, energy efficiency when traveling in urban areas.

In the case of power generation from the engine braking state (power generation by rotational inertia energy), the amount of heat generated by the engine of the generator 8 is smaller than that during normal power generation, so increase the rotational speed if mechanical rotation strength and the like can be secured. No problem,
Since heat radiation to the generator 8 directly attached to the engine 7 is reduced, there is no thermal problem even if the output of the electric motor is increased.

In the above embodiment, when the brake is depressed, the inverter circuit 5 is operated to supply a part of the regenerative electric power to the generator (electric motor) 8 to drive it. When the regenerative power of the motor 3 is detected and the charge allowable level of the main battery 1 is exceeded, a regenerative power signal may be output to the inverter circuit 5 to operate the inverter circuit 5 and drive the generator 8 as an electric motor. .

[0036]

According to the present invention, the regenerative electric power is supplied to the battery while being supplied to the generator that also serves as the electric motor to forcibly rotate the stopped engine. It is possible to reduce the load on the mechanical brake while limiting the charging current to the battery to an allowable value.

Further, after the regenerative braking of the traveling electric motor is released, the generator that also serves as the electric motor is operated as a generator by the rotational inertia energy of the forced rotation so that the generated electric power is supplied to the battery. Since the configuration is adopted, after regenerative braking, the generator can be operated by the rotational inertia energy to charge the battery, and the energy efficiency of the engine can be improved. In particular, it is possible to improve energy efficiency in city driving, which often involves repeated acceleration and deceleration.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a hybrid power supply device for an electrically driven vehicle according to an embodiment of the present invention.

FIG. 2 is a diagram showing a charge / discharge state of a main battery and an engine speed of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main battery, 2 ... Running controller, 3 ... Running motor, 4 ... Engine start signal, 5 ... Inverter circuit, 6 ... Engine drive generator, 7 ... Engine, 8 ... Generator, 9 ... Rectifier circuit, 10 ... Regenerative braking controller, 11 ... Accelerator position detection signal, 12 ... Brake operation detection signal, 20 ...
Inverter unit.

Claims (3)

[Claims] 1. A battery for driving a traveling electric motor, which serves as a traveling drive source, and an engine-driven generator that supplies electric power to the battery, and the engine generator is provided when the remaining battery level decreases. In a hybrid power supply device for an electrically driven vehicle configured to drive to compensate for a battery shortage, the engine-driven generator is an engine and a generator driven by the engine while the engine is operating. A generator that also serves as an electric motor for starting the engine, and supplies the regenerative electric power to the battery as charging power during regenerative braking of the traveling electric motor while also supplying the regenerative electric power to the electric motor. The engine is forcibly rotated when it is stopped and used as a brake load. A hybrid power supply device for an electric traveling vehicle. 2. After the regenerative braking of the electric motor for traveling is released, the generator that also serves as the electric motor is operated by the rotational inertia energy of the forced rotation as a generator to supply the generated electric power to the battery. The hybrid power supply device for an electrically driven vehicle according to claim 1, wherein the hybrid power supply device is configured as described above. 3. The electric running system according to claim 1, wherein the regenerated electric power is boosted and supplied to the battery and the generator that also serves as the electric motor, and further boosted when the brake is operated. Vehicle hybrid power supply.