JP2000278807A - Power system for hybrid electric vehicle - Google Patents

Abstract

(57) [Problem] In a hybrid electric vehicle in which a main power storage device is an electric double layer capacitor battery, initial charging or preliminary charging of the main power storage device is performed by an engine generator and a rectifier, so that charging from an external power supply is unnecessary. To SOLUTION: This hybrid electric vehicle drives an AC motor for driving a vehicle via an inverter with a DC output of a polyphase rectifier connected to a polyphase AC generator driven by a vehicle engine or power of a vehicle main power storage device. In addition, the present invention relates to a hybrid electric vehicle in which the rectifier includes a voltage-type self-excited converter, and the main power storage device includes an electric double layer capacitor battery. When the voltage of the main power storage device 4 is equal to or lower than a specified value, the main power storage device 4 is charged via the engine 1, the generator 2, and the rectifier 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system for a hybrid electric vehicle using an electric double layer capacitor battery as a main power storage device.

[0002]

2. Description of the Related Art FIG. 12 shows a basic configuration of a power supply system in which an electric double layer capacitor is applied to a main power storage device of a hybrid electric vehicle. Conventionally, chemical batteries have been applied to power storage devices, but chemical batteries have a short charge-discharge cycle life,
In addition, due to poor efficiency at the time of high output operation, application of an electric double layer capacitor battery has recently been proposed.

In FIG. 12, 1 is an engine, 2 is an AC generator, 3 is a rectifier, 4 is a main power storage device, and 5 is an inverter for driving an AC motor 6 for driving the vehicle. , The rectifier 3, the main power storage device 4, the inverter and the electric motor 6 constitute a power train. The main power storage device 4 includes a plurality of electric double layer capacitor cells 41 and 4.
, Are connected in series to form an electric double layer capacitor battery. In FIG. 12, illustration of a vehicle drive mechanism after the electric motor 6 and auxiliary equipment such as an air conditioner is omitted.

FIG. 12 shows a series hybrid electric vehicle in which a main power storage device 4 is partially or entirely charged with electric power generated by an engine 1 and a generator 2. The vehicle is driven by the electric motor 6 via the inverter 5 using both the electric power generated by the engine 1 and the electric generator 2 and the electric power of the main power storage device 4. During acceleration, the power of the generator 2 and the power of the main power storage device 4 or the power of the main power storage device 4
The electric motor 6 is accelerated and driven through the inverter 5 using only the electric power. On the other hand, during regenerative braking, the braking power generated in electric motor 6 is regenerated to main power storage device 4 via inverter 5.

[0005] As described above, the main power storage device 4 is repeatedly operated during discharging of the vehicle during acceleration of the vehicle and charging during regenerative braking, and the number of times reaches tens of thousands. The main power storage device for a hybrid electric vehicle must withstand this number of charge / discharge cycles. The power storage device composed of the electric double layer capacitor battery described above has this performance,
It can be said that this is an excellent power storage device for a hybrid electric vehicle. The electric double layer capacitor battery of the main power storage device 4 shown in FIG. 12 is the same as the electric double layer capacitor cells 41 and 4 as in the case of the battery pack in which a number of conventional chemical secondary batteries are connected in series.
2, 43,... Are connected in series.

[0006] The stored energy of an electric double layer capacitor is proportional to the square of the voltage of the capacitor. In other words, when used as a DC power supply, the voltage of the electric double layer capacitor decreases as the energy consumption increases.
If 75% of the energy is used, the voltage drops by half. When the battery is over-discharged, the voltage is further reduced. When the battery is over-discharged, which corresponds to the end of discharge of a conventional chemical battery, the capacitor battery becomes almost zero. On the other hand, in the conventional chemical battery, the voltage is maintained at １ ／ or more of the voltage at the time of full charge even in the overdischarge state.

FIG. 13 shows the terminal voltage of the main power storage device with respect to the amount of discharge (DOD) in comparison between a chemical battery and an electric double layer capacitor battery. In the figure, a shows the characteristics of the chemical battery, and b shows the characteristics of the electric double layer capacitor battery. From the figure, in the discharge state where the discharge amount is 90% or more, the voltage is about 50% or more in the chemical battery, whereas the voltage becomes almost zero in the electric double layer capacitor battery.

The electric double layer capacitor battery shown in FIG. 12 has a configuration in which a large number of capacitor cells 41, 42, 43,... Are connected in series, but usually, as shown in FIG. 411-413, 421-4
23, 431 to 433) are connected in series and parallel.

[0009]

When charging an electric double layer capacitor battery by an engine generator as shown in FIG. 12, a major problem is the initial charge and preliminary discharge of the electric double layer capacitor battery. The initial charging is charging from the voltage of the electric double layer capacitor battery being zero, and the preliminary charging is charging from the voltage of the electric double layer capacitor battery being lower than the specified voltage. The minimum voltage of the generator cannot be lower than the voltage generated during idling operation of the engine. In a conventional chemical battery, if the initial charge is performed once after mounting on a vehicle, the battery voltage is secured to a voltage equal to or more than 1/2 of the full charge, and the charge current is controlled to a specified value by controlling the generator and the rectifier. It was possible to charge.

[0010] However, in the case of an electric double layer capacitor battery, the voltage value may be almost zero in an overdischarge state. In this case, it is impossible to charge the battery by controlling the engine generator and the rectifier as in the case of the conventional chemical battery. For this reason, a charging method using an external power supply as shown in FIG. 15 has been conventionally used.

In FIG. 15, the same components as those in FIG. 12 are denoted by the same reference numerals. In the figure, reference numeral 100 denotes a hybrid electric vehicle, which has substantially the same configuration as that of FIG. 7 is an external power supply, 8 is a charger, 9 is a car 10
This is a connection section for connecting the charger 0 and the charger 8. Main power storage device 4
When the electric double layer capacitor battery is initially charged or precharged, the charger 8 is connected to the connection portion 9 of the vehicle 100 and charged from the external power supply 7.

The conventional charging method has the following major problem. (1) It is necessary to perform charging from an external power source every time initial charging or preliminary charging is performed, which complicates the charging operation of the electric double layer capacitor battery. (2) Preliminary charging becomes impossible in a place where an external power supply cannot be secured. If the preliminary charging becomes impossible, the hybrid electric vehicle cannot run, which is a fatal problem for the vehicle.

Therefore, the present invention provides an electric double-layer capacitor battery which uses an output of an engine generator for initial charging and preliminary charging in a hybrid electric vehicle using an electric double-layer capacitor battery as a main power storage device. It is intended to provide a power supply system.

[0014]

According to the present invention, basically, when the terminal voltage of a main power storage device composed of an electric double layer capacitor battery is zero or less than a specified value such as nearly zero. The main power storage device is charged via an engine generator and a rectifier. Also, the present invention
The output short-circuit current of the alternator is made by paying attention to the fact that it is determined by the impedance of the alternator itself.When the terminal voltage of the main power storage device is charged at a specified value or less, the impedance of the alternator itself, The magnitude is set so that the charging current becomes equal to or less than a specified value. Furthermore, the charging current of the main power storage device is limited to a specified value or less by providing a current limiting circuit consisting of impedance between the generator and the rectifier, or by connecting a resistor between the rectifier and the main power storage device. Is what you do.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a main part of the first embodiment of the present invention, and corresponds to the first to sixth embodiments of the present invention. The same components as those in FIG. 12 are denoted by the same reference numerals.

In FIG. 1, the AC generator 2 is a permanent magnet type synchronous generator, and is shown in a three-phase case. Rectifier 3
Is a voltage type self-excited rectifier, and is a semiconductor switch arm 31.
u, 31v, 31w, 31x, 31y, 31z. These switch arms are
A semiconductor switching element and a diode are connected in anti-parallel as shown in the figure. In the figure, the semiconductor switching elements 31 of the semiconductor switch arms 31u and 31x are shown.
Only numbers 0u, 310x and diodes 311u, 311x are numbered, and other switch arms are omitted. A main power storage device 4 composed of an electric double layer capacitor battery is connected to both ends of the rectifier 3 on the DC output side.

Next, the charging operation of the embodiment of FIG. 1 will be described with reference to FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals. The control method of the rectifier 3 shown in FIG. 2 is a known PWM control (sine wave-triangle wave modulation method). For this control, between the voltage v _c and the generator line voltage effective value v _g of the electric double layer capacitor cell (main power storage device 4), and the relationship of Equation 1 is always maintained.

[0018]

[Number 1] ^{_{v g ≦ (1.5) 1/2 /}} 2 × v c

[0019] However, if v _c is smaller than the voltage value shown in the above equation, that is, if a zero voltage or the like, since the normal control of the rectifier 3 can not be performed, is as follows. That is,
The engine 1 is started while the control operation of the rectifier 3 is stopped, and the engine 1 is operated at an idling speed. As a result, a voltage corresponding to the idling rotation is generated in the AC generator 2. At this time, since the peak value voltage of the voltage between the generator line is a larger than the voltage v _c of the main power storage device 4, the current (direction of flow in the V phase from the U-phase in the illustrated example) the direction of the arrow in FIG. 2 flow,
The main power storage device 4 is charged.

FIG. 3 is an equivalent circuit diagram of a main part during charging in FIG. In the figure, 2a is the induced voltage source of the generator 2, which generates a voltage v _g. 2b is an equivalent impedance of the winding of the generator 2, which is a combination of an equivalent reactance 20b of the winding and an equivalent resistance 21b of the winding. Charging current _ic of main power storage device 4 is a current limited by this impedance 2b. Note that 31
1u and 311v are semiconductor switch arms 31 respectively.
u, 31y.

FIG. 4 shows operation waveforms of various parts during charging. In the figure, n is the number of revolutions of the engine 1,
v _g is the induced voltage (the line voltage effective value) of the generator 2, v _c is the main power storage device 4 of the voltage, i _c is the charging current of the main power storage device 4. In this example, the operation when the generator 2 is a permanent magnet type synchronous generator is shown.

In FIG. 4, the engine 1 is started at time t = 0. Engine speed is increased, it continues to rotate in the idling speed N _0. At this time, the induced voltage of the generator 2 v _g also rises in proportion to the engine speed. In response to an increase in the generator induced voltage v _g, since charging current flows i _c,
Main power storage device 4 is charged, the voltage v _c is gradually increased. On the other hand, since the generator induced voltage v _g is constant, in response to an increase in the voltage v _c of the main power storage device 4, the charging current i _c is reduced. Thereafter, the voltage v _c of the main power storage device 4 at time t = T completes the charge reaches the fully charged voltage V _0. Then, the charging operation is terminated by stopping the engine 1.

FIG. 5 is a circuit diagram showing a main part of a second embodiment of the present invention, and corresponds to the seventh embodiment of the present invention. 5, the same components as those of FIG. 1 are denoted by the same reference numerals. In this embodiment, a current limiting circuit 200 is connected between the AC generator 2 and the rectifier 3. FIG. 5 shows the case of three phases, and the impedance 2
00u, 200v, and 200w are connected in series to each phase. When the pre-charging of the main power storage device 4 is completed, the short-circuit switches 201u, 201v, 201w are connected in parallel to the respective impedances as shown in the figure to short-circuit the respective impedances 200u, 200v, 200w.

In the embodiment of FIG. 5, impedance 200u, 2u is used as a shortage of the impedance of generator 2 necessary to keep the charging current of main power storage device 4 at a specified value or less.
00v and 200w are added outside the generator to limit the charging current. These impedances may be resistances having the same current limiting effect as described in claim 8, or may be reactors having the same current limiting effect as described in claim 9.

FIG. 6 is a circuit diagram showing a main part of a third embodiment of the present invention, and corresponds to the tenth embodiment of the present invention. 6, the same components as those in FIG. 12 are denoted by the same reference numerals. In the embodiment of FIG. 6, a resistor 32 is connected between the rectifier 3 and the main power storage device 4. A switch 33 that short-circuits when the pre-charging of the main power storage device 4 is completed is connected in parallel to the resistor 32.

FIG. 7 is a circuit diagram showing a main part of a fourth embodiment of the present invention, and corresponds to the eleventh embodiment of the present invention. FIG. 7 shows the case of three phases.
An AC switch 21 is inserted in one phase between the generator 2 and the rectifier 3. The same components as those in FIG. 12 are denoted by the same reference numerals.

In this embodiment, the AC switch 21 is opened during the initial charging or the preliminary charging of the main power storage device 4,
The rectifier 3 is operated as a single-phase rectifier. In the case of three-phase, the no-load output voltage (average value) of the rectifier 3 is about 1.35 times the effective value of the no-load line voltage of the generator 2, but is about 0.9 times in the case of a single phase. As a result, the charging voltage decreases and the charging current decreases. This embodiment is particularly effective when the charging current is large and the current needs to be reduced.

FIG. 8 is a circuit diagram showing a main part of a fifth embodiment of the present invention, and corresponds to the twelfth embodiment of the present invention. 8, the same components as those in FIG. 12 are denoted by the same reference numerals. In the embodiment of FIG. 8, a switch 10 for disconnecting inverter 5 from main power storage device 4 is inserted between main power storage device 4 and inverter 5 at the time of initial charging or preliminary charging of main power storage device 4. Main power storage device 4
At the time of initial charging or preliminary charging, the switch 10 is operated to disconnect the inverter 5 from the main power storage device 4.

FIG. 9 is a circuit diagram showing a main part of a sixth embodiment of the present invention, and corresponds to an embodiment of the present invention. 9, the same components as those of FIG. 8 are denoted by the same reference numerals. In FIG. 9, reference numeral 1a denotes a rotation speed command device for variably controlling the idling rotation speed of the engine 1 in accordance with the charging voltage when the main power storage device 4 is charged.
Is added to the configuration of FIG.

FIG. 10 shows the operation of each section in FIG. 9. In this example, the charging current i of the main power storage device 4 is shown.
_The figure shows a case where the idling rotational speed n of the engine 1 is continuously controlled by the rotational speed command device 1a so that _c becomes substantially constant. Generator induced voltage v _g varies in proportion to the idling speed n, main power storage device voltage v _c is linearly increased at time t = charge completion voltage V at time T ₀ to 4
To complete charging. Then, the charging operation is terminated by stopping the engine 1.

FIG. 11 shows another example of the operation of the embodiment shown in FIG.
This is a case where the idling speed of the engine 1 is switched between two stages. In the case of the charging method shown in FIGS. 10 and 11, the charging time is significantly reduced as compared with the charging method shown in FIG.

In the above embodiment, the present invention is applied to a series hybrid electric vehicle. However, other hybrid electric vehicles such as a parallel hybrid electric vehicle (an engine generator and an electric Needless to say, the present invention can be applied to an electric vehicle equipped with a multilayer capacitor battery).

[0033]

As described above, according to the present invention, in a hybrid electric vehicle equipped with an engine generator using an electric double layer capacitor battery as the main power storage device, the initial charging and the preliminary charging of the main power storage device are performed by the engine generator and The following effects are expected because the power supply system is operated via a rectifier. 1) The initial charging and the preliminary charging of the main power storage device (electric double layer capacitor battery) can be performed directly from the engine generator mounted on the vehicle, and the charging from the external power source as in the related art is unnecessary, so that the practicability is high. A power supply system for a hybrid electric vehicle can be realized. 2) It is possible to provide a practical hybrid electric vehicle by realizing a long-life battery by promoting the application of an electric double layer capacitor battery as a main power storage device of the hybrid electric vehicle.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing a main part of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation at the time of charging of FIG. 1;

FIG. 3 is an equivalent circuit diagram of a main part of FIG. 2;

4 is an operation waveform diagram of each unit in FIG.

FIG. 5 is a circuit diagram showing a main part of a second embodiment of the present invention.

FIG. 6 is a circuit diagram showing a main part of a third embodiment of the present invention.

FIG. 7 is a circuit diagram showing a main part of a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram of a power supply system of a hybrid electric vehicle according to a fifth embodiment of the present invention.

FIG. 9 is a configuration diagram of a power supply system of a hybrid electric vehicle according to a sixth embodiment of the present invention.

FIG. 10 is an operation explanatory diagram of FIG. 9;

FIG. 11 is another operation explanatory view of FIG. 9;

FIG. 12 is a circuit configuration diagram of a power supply system of a conventional hybrid electric vehicle.

FIG. 13 is an operation explanatory diagram of FIG.

FIG. 14 is a configuration diagram of a main power storage device.

FIG. 15 is an explanatory diagram of initial charging and preliminary charging of the main power storage device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 1a Idling speed command device 2 AC generator 2a Generator induced voltage source 2b Generator winding equivalent impedance 3 Rectifier 4 Main power storage device (electric double layer capacitor battery) 5 Inverter 6 Vehicle driving AC motor 7 External power source 8 Charger 9 Connecting part 10, 33 Switch 20b Generator winding equivalent reactance 21 AC switch 21b Generator winding equivalent resistance 31u, 31v, 31w, 31x, 31y, 31z Semiconductor switch arm 32 Resistance 41, 42, 43, 411 , 412, 413, 421,
422, 423, 431, 432, 433 Electric double layer capacitor cell 100 Hybrid electric vehicle 200 Current limiting circuit 200u, 200v, 200w Impedance 201u, 201v, 201w Impedance short circuit switch 310u, 310v, 310w, 310x, 310y,
310z semiconductor switching elements 311u, 311v, 311w, 311x, 311y,
311z diode

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 29/06 H02J 7/16 X H02J 7/16 B60K 9/00 E (72) Inventor Jun Yamada Saitama 1-chome, Ageo 1-chome Nissan Diesel Industry Co., Ltd. F-term (reference) 3G093 AA07 AA16 CA04 EA03 EB09 FA11 FA13 FB01 FB03 5G060 AA04 BA04 CA13 DA01 5H115 PA15 PC06 PG04 PI16 PI24 PO01 PO06 PO10 PU01 PU21 PV09 PV22 TI05 TI06 TR19

Claims (14)

[Claims] 1. A hybrid electric vehicle that drives a vehicle-driving AC motor via an inverter with a DC output of a polyphase rectifier connected to a polyphase AC generator driven by a vehicle-mounted engine or power of a vehicle-mounted main power storage device. In the hybrid electric vehicle, wherein the rectifier includes a voltage-type self-excited converter, and the main power storage device includes an electric double layer capacitor battery, a voltage of the main power storage device is equal to or lower than a specified value. A power supply system for a hybrid electric vehicle, wherein the main power storage device is charged via the engine, the generator, and the rectifier. 2. The power supply system for a hybrid electric vehicle according to claim 1, wherein the specified value is a voltage value at which the charging current cannot be controlled by the rectifier. 3. The power supply system for a hybrid electric vehicle according to claim 1, wherein the specified value is a peak value of a line voltage of the generator. 4. The power supply system for a hybrid electric vehicle according to claim 1, wherein the semiconductor switching element forming the rectifier is turned off when the main power storage device is charged. Power supply system for electric vehicles. 5. The power supply system for a hybrid electric vehicle according to claim 1, wherein a rotation speed of the engine is maintained at an idling rotation speed when the main power storage device is charged. Power system for hybrid electric vehicles. 6. The power supply system for a hybrid electric vehicle according to claim 1, wherein the impedance of the generator itself is changed when the main power storage device is charged. A power supply system for a hybrid electric vehicle, wherein a value of a current flowing through a power storage device is set to be equal to or less than a specified value. 7. The power supply system for a hybrid electric vehicle according to claim 1, wherein a current limiting circuit comprising an impedance between the generator and the rectifier when the main power storage device is charged. And a current flowing through the generator, the rectifier, or the main power storage device is set to a specified value or less. 8. The power supply system for a hybrid electric vehicle according to claim 7, wherein the impedance is a resistance. 9. The power supply system for a hybrid electric vehicle according to claim 7, wherein the impedance is a reactor. 10. The power supply system for a hybrid electric vehicle according to claim 1, wherein a resistor is connected between the rectifier and the main power supply device when the main power storage device is charged, A power supply system for a hybrid electric vehicle, wherein a current flowing through the generator, the rectifier, or the main power storage device is set to a specified value or less. 11. The power supply system for a hybrid electric vehicle according to claim 1, wherein a circuit switch is connected to at least one phase between the generator and the rectifier, and A power supply system for a hybrid electric vehicle, comprising: opening at least one phase of the circuit switch so that the rectifier performs a single-phase rectification operation when charging a power storage device. 12. The hybrid electric vehicle power supply system according to claim 1, wherein said inverter is separated from said main power storage device when said main power storage device is charged. Automotive power system. 13. The power supply system for a hybrid electric vehicle according to claim 1, wherein an idling speed of the engine is increased in accordance with an increase in a charging voltage of the main power storage device. Hybrid electric vehicle power system. 14. The power supply system for a hybrid electric vehicle according to claim 13, wherein the idling speed of the engine is increased stepwise.