JP2002271907A - Controller for hybrid electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize a junction box 75 provided between a battery 61 and an inverter 65. SOLUTION: Reserve charging of a capacitor 79 is conducted by the generated output of a generator 63 driven by an engine 59. A control means is provided which switches a main contactor 73 if it is judged that the reserve charging is completed and connects the battery 61 with the inverter 65. As a result, use of a precharging circuit can be eliminated, thereby downsizing the junction box 75.

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 hybrid electric vehicle having an inverter for converting a direct current into an alternating current.

[0002]

2. Description of the Related Art FIG. 4 shows an overall configuration diagram of a conventional series hybrid electric vehicle.

Conventionally, as shown in FIG. 4, a generator 3 mechanically connected to an engine 1 and a battery 5 charged by the generator 3 are connected to an inverter 7 so that the generator 3 and the battery 5 Is supplied to the motor 9 after being converted into an alternating current by the switching operation of the inverter 7.

[0004] A smoothing capacitor 11 is connected in parallel to the inverter 7 so that a voltage fluctuation occurs in the capacitor 1.
Suppressed by 1. Therefore, a rectified current is input to the inverter 7, and the operation of the inverter 7 is stabilized.

[0005] Contactors 15 and 17 are provided between the inverter 7 and the battery 5, and the battery 5 and the inverter 7 are connected and disconnected according to a key operation of the vehicle. Specifically, a main circuit 19 is provided in a junction box 13 interposed between the battery 5 and the inverter 7.
And a precharge circuit 23 in which a precharge resistor 21 is connected in series, and a main contactor 15 and a precharge contactor 17 are provided in each circuit.
Is provided.

During operation of the vehicle, the main contactor 15 is turned on (connected state) and the precharge contactor 17 is turned off (disconnected state).
9, the power of the battery 5 is input to the inverter 7. Further, when the key-off operation is performed by the occupant, the main contactor 15 is turned off in conjunction with the operation. As a result, when the vehicle is not traveling, the connection between the battery 5 and the inverter 7 is cut off, so that the voltage of the battery 5 is prevented from being transmitted to the motor 9 via the inverter 7, and the safety of the vehicle is ensured. Incidentally, when the main contactor 15 is turned off, the capacitor 11 connected to the inverter 7 is discharged and becomes approximately 0V.

Thereafter, when a key ON operation is performed by the occupant, first, the precharge contactor 17 provided in the precharge circuit 23 is turned on (connected state).
As a result, after the voltage of the battery 5 is reduced by the precharge resistor 21, the voltage is input to the inverter 7, and the capacitor connected to the inverter 7 is precharged (precharged). Then, when it is determined that the voltage of the capacitor 11 has become equal to or higher than the predetermined value and the precharge of the capacitor 11 has been completed, the main contactor 15
At the same time, the precharge contactor 17 is turned off, and the power of the battery 5 is input to the inverter 7 through the main circuit 19.

Therefore, when the key is turned on, the capacitor 11 is charged with a low current value until the capacitor 11 reaches a predetermined voltage in advance by the action of the precharge resistor 21 connected to the precharge circuit 23. And the capacitor 11 connected to the inverter 7 is reduced in potential, and a large current is prevented from flowing through the circuit when the battery 5 and the inverter 7 are connected with the main contactor 15 turned ON. As a result, welding of the contact of the main contactor 15 due to a large current flowing through the circuit is avoided.

[0009]

However, in such a conventional control apparatus for a hybrid electric vehicle, both the main circuit and the precharge circuit are provided between the battery and the inverter in order to protect the contacts of the contactor as described above. Is required, and it is necessary to operate both the main contactor and the precharge contactor provided in the main circuit and the precharge circuit in accordance with the occupant's key ON / OFF operation, which complicates the structure of the device. However, there is a problem that the size increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to reduce the size of an apparatus and improve the degree of freedom in design.

[0011]

In order to solve the above-mentioned problems, according to the present invention, a capacitor is precharged by a power generation output of a generator accompanying operation of an engine, and a switch is provided by a switch means when the precharge is completed. Since the control means for connecting the battery and the inverter is provided, the precharge of the capacitor connected to the inverter can be appropriately performed without the precharge circuit and the precharge contactor.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A control device for a series hybrid electric vehicle according to an embodiment of the present invention will be described below in detail with reference to FIGS. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is an enlarged view of a main part of the embodiment of the present invention, and FIG. 3 is a flowchart showing an operation state of the embodiment of the present invention.

As shown in FIG. 1, a wheel drive motor 51 mounted on a vehicle is mechanically connected to a wheel drive system member 53 and supplies power to left and right drive wheels 57, 57 via a differential 55. Is communicating. The vehicle is equipped with an engine 59 and a battery 61 as a power supply source for the motor 51.

The engine 59 is mechanically connected to a generator 63, and the power of the engine 59 is
3 and converted into electric power by the generator 63
Is a motor 51 and a battery 61 via an inverter 65.
And the power generated by the generator 63 can be supplied to the motor 51 and the battery 61.

The battery 61 is connected to the motor 51 via an inverter 65, and electric power according to the pedal operation of the occupant is supplied from the battery 61 to the motor 51. Further, a sub-battery 67 for driving the accessories is connected to the battery 61 via a DC / DC converter 69, and when the charge amount of the sub-battery 67 decreases, the sub-battery 67 is charged.

The switching operation of the inverter 65 connected to the generator 63 and the battery 61 is controlled by the controller 71. After the DC current input from the generator 63 and the battery 61 is converted to an AC current by the switching operation, the inverter 65 is connected to the inverter 65. An alternating current is supplied to the motor 51. Also, as shown in FIG.
A main contactor 73 (switch means) is provided between the inverter 65 and the battery 61.
And the battery 61 can be connected and disconnected. That is, a main circuit 77 having a main contactor 73 is formed in a junction box 75 interposed between the inverter 65 and the battery 61, and the ON / OFF operation of the main contactor 73 is controlled by the controller 71. . Therefore, when the vehicle is running, the main contactor 73 is turned on (connected state), and the battery 61 and the inverter 65 are connected so that power can be supplied. When the vehicle is not running, the battery 61 and the inverter 65 are disconnected.

Further, a capacitor 7 is connected to the inverter 65.
9 are connected in parallel, and even if there is a sudden change in the voltage input to the inverter 65 during running of the vehicle, the capacitor 7
9, the voltage fluctuation is suppressed, and the operation of the inverter 65 is stabilized. In addition, the capacitor 79
A voltmeter (not shown) is provided to detect whether or not the voltage of the capacitor 79 has reached a predetermined precharge voltage Vp, and the detection result is input to the controller 71.

The above-mentioned engine 59, generator 63, battery 61, inverter 65, and motor 51 are connected to a controller 71, respectively.
1 controls each operation in an integrated manner. More specifically, when the occupant's accelerator pedal operation amount, brake pedal operation amount, battery charge amount, and the like are input to the controller 71 from the corresponding sensors, the target engine speed and the target generator power generation amount are calculated, and the engine 5
The fuel injection amount, the throttle opening, and the like are feedback-controlled so that the actual engine speed 9 and the actual generator power generation amount of the generator 63 approach the target values. Further, the controller 71 calculates an output torque according to the operation amount of the accelerator pedal, the brake pedal and the like of the occupant, and generates a pulse width modulation signal based on the output torque. Then, by inputting the pulse width modulation signal to the switching element constituting the inverter 65,
The switching operation of the inverter 65 is feedback-controlled so that a desired output torque is generated in the motor 51 connected to the inverter 65.

Next, an operation state of the control device for a hybrid electric vehicle according to the present invention having the above-described configuration will be described with reference to a flowchart shown in FIG.

First, when the control is started by detecting the key ON operation of the occupant, it is determined in step S10 whether or not the engine 59 is operating. The engine operation determined here is an engine operation performed when the key is turned on to check the operation of the engine 59 regardless of the charge amount of the battery 61. Here, it is determined that the engine 59 is not operating. In this case, the control of the present invention cannot be performed, and thus the control is terminated. On the other hand, when it is determined in step S10 that the engine 59 is operating, the process proceeds to step S20.

In step S20, power generation control is performed in generator 63. The power generation control is to control the amount of power generated by the generator 63 so that desired power is obtained. Here, the power generation is controlled so that a current value corresponding to the precharge current (for example, 20 A) in the conventional device is obtained. The exciting current and the like of the generator 63 during the control are set in advance.

Then, in step S20, the generator 6
3, the generator 63 is electrically connected to the inverter 65 as described above.
5 is supplied to a capacitor 79 connected thereto, and the capacitor 79 is precharged. Here, the pre-charging means charging the capacitor 79 to a predetermined voltage before connecting the capacitor 79 discharged to approximately 0 V and the high-voltage battery 61 by turning on the main contactor 73. In this apparatus, the generator 63 associated with the operation of the engine 59 is used as described above.
The above-described pre-charging is performed by the power generation output. Further, the amount of power generated by the generator 63 in the power generation control described above may be appropriately determined according to the capacity of the capacitor 79 or the like, and may be variable according to the voltage value of the capacitor 79 instead of a constant value. Then, when the generator 63 generates power in step S20, the process proceeds to step S30.

Next, in step S30, the capacitor 7
9 determines whether or not the voltage of the capacitor 79 has reached a predetermined precharge voltage Vp. Here, the voltage of the capacitor 79 is equal to the precharge voltage Vp.
If it is determined that the voltage has not reached the threshold value, the process returns to step S20, and the power generation control in step S20 is continued until it is determined in step S30 that the capacitor voltage has reached the pre-charge voltage Vp. When it is determined in step S30 that the capacitor voltage has reached Vp, the process proceeds to step S40. Note that the precharge voltage Vp is such that the potential difference between the capacitor 79 and the battery 61 is sufficiently low even when the battery 61 and the inverter 65 are connected by turning on the main contactor 73 in step S40 described later. Means a capacitor voltage that can prevent a large current from flowing through the main circuit 77,
What is necessary is just to determine suitably according to the capacity | capacitance etc. of the battery 61 and the capacitor 79.

Then, in step S30, it is determined that the capacitor voltage has reached the pre-charge voltage Vp, and step S4
When proceeding to 0, the controller 71 outputs a connection command to the main contactor 73. As a result, the main contactor 73 switches from OFF to ON, and the battery 61 and the inverter 65 are connected.
Is input to the inverter 65.

When the main contactor 73 is turned on in step S40, the process proceeds to step S50, and the control is terminated after the power generation control performed in step S20 is terminated.

As described above, in the control apparatus for a hybrid electric vehicle according to the present invention, the power of the engine 59 operated for checking the operation when the key is turned on is used in step S.
At 20, power generation control by the generator 63 was performed, and the power obtained by the power generation control was used for preliminary charging of the capacitor 79 connected to the inverter 65. As a result, even without the precharge circuit, the precharge resistor included in the precharge circuit, the precharge contactor included in the precharge circuit, and the like, the precharge of the capacitor 79 is appropriately performed. The potential difference between the main contactor 73 and the capacitor 79 is reduced, so that a large current is prevented from flowing through the main circuit 77 when the key is turned on, and welding of the contact of the main contactor 73 is avoided. The size of the junction box 75 can be reduced by eliminating the need for the precharge circuit.

In the above control, step S50
However, if it is determined that the driving of the engine 59 and the power generation by the generator 63 are necessary continuously by detecting the accelerator pedal operation amount, the battery charge amount, and the like, The drive of 59 and the power generation by the generator 63 are continuously performed.

Further, in the above embodiment, the case where the present apparatus is applied to a series type hybrid electric vehicle has been described. However, it is naturally applicable to other types of hybrid vehicles such as a parallel type. The generator connected to the engine and the motor connected to the inverter may be one component (motor / generator) that can switch between the generator function and the motor function.

In the above embodiment, the capacitor 79
A voltmeter is provided, and when the voltage of the capacitor 79 reaches a predetermined value, it is determined that the pre-charge has been completed and the main contactor 73 is turned on. However, the present invention is not limited to this. Measure the time from the start of control,
The configuration may be such that when the predetermined time has elapsed, it is determined that the preliminary charging has been completed, and the main contactor 73 is turned on.

[0030]

As described above in detail with the embodiments, in the hybrid electric vehicle control device of the present invention, the capacitor is precharged by the power generation output of the generator accompanying the operation of the engine, and the precharge is performed. Since the control means for connecting the battery and the inverter by the switch means at the time of completion is provided, the pre-charging of the capacitor is appropriately performed with a relatively simple configuration, and the size of the apparatus is reduced because the pre-charge circuit is omitted. And the degree of freedom in design is improved.

[0031]

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a control device for a hybrid electric vehicle according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of a control device for a hybrid electric vehicle according to an embodiment of the present invention.

FIG. 3 is a flowchart showing an operation state of the control device for the hybrid electric vehicle according to the embodiment of the present invention.

FIG. 4 is an overall configuration diagram showing a conventional hybrid electric vehicle.

[Explanation of symbols]

 51 Motor 59 Engine 61 Battery 63 Generator 65 Inverter 71 Controller 73 Main Contactor 75 Junction Box 77 Main Circuit 79 Capacitor

Continued on the front page F-term (reference) QN03 QN04 RB22 RE03 RE05 SE04 SE05 SE06 TE02 TI01 TO14 TO21 TO23

Claims (1)

[Claims] 1. An engine, a generator driven by the engine, a battery connected to the generator so as to be capable of transmitting power, and an inverter for converting at least a DC current input from the battery into an AC current.
A switch for disconnecting the battery from the inverter, a smoothing capacitor connected to the inverter, and a motor driven by an alternating current output from the inverter; And a control means for connecting the battery and the inverter by the switch means when the preliminary charge is completed. apparatus.