JP3045019B2 - Power generation control device for hybrid electric vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle having an engine in addition to a motor, that is, a hybrid electric vehicle (HV), and more particularly to a power generation control device for controlling a generator of the vehicle.

[0002]

2. Description of the Related Art An HV is an electric vehicle equipped with an engine in addition to a motor as a power source of the vehicle. The HV includes a series HV (SHV) and a parallel HV (PHV). In the former, the generator is driven by the mechanical output of the engine, and the motor for driving the vehicle is driven by using the output of the generator and the output of the battery discharged from the vehicle. In the latter case, when the vehicle is driven by using the mechanical output of the engine, the excess or deficiency of the engine output is assisted or absorbed by the motor / generator.

[0003] In the SHV, a gearbox is usually provided between an engine and a generator. When transmitting the mechanical output of the engine to the generator, the speed increaser is a mechanism for increasing the rotation speed to a value suitable for the generator. By using such a mechanism, the rated speed of the generator can be sufficiently increased, and the generator can be downsized.

[0004]

The power transmission system from the engine to the generator usually does not have a clutch mechanism. Therefore, the rotating system of the engine includes the rotor of the generator and the like. The resonance frequency of this rotating system is usually the idling speed of the engine (for example, 700 rpm).
The frequency becomes lower (for example, 400 rpm).

When starting the engine, it is necessary to increase the engine speed from 0 rpm to the idle speed, so that the engine must pass the above-mentioned resonance frequency. Here, the inertia of the rotor of the generator is large, and the gearbox is provided, so that vibrations and rattles are generated from the backlash portion of the gears constituting the gearbox due to resonance. When stopping the engine, it is necessary to reduce the engine speed from idle speed to 0 rpm,
After all, the above resonance frequency has to be passed. In this case, although the engine does not serve as a vibration source, the plurality of cylinders usually function as mechanical resistance, so that resonance occurs similarly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been made in consideration of the resonance of a rotating system including a rotor of a generator by controlling the generator when starting and stopping the engine. And to reduce vibration and the like.

[0007]

In order to achieve the above object, a power generation control device according to the present invention comprises a power generator control device.
Inertia of the rotating system of the engine including the
Means for operating the generator as a motor when the engine is started by the starter to generate torque in the same direction as the engine rotation, and means for operating the generator as a generator after the engine is started. Features.

[0008] The power generation control device according to the present invention includes means for operating the generator as a generator before the engine is stopped, means for operating the generator as a motor when the engine is stopped, and reducing the rotational energy of the engine. It is characterized by having.

[0009]

In the present invention, when starting the engine, the generator is operated as a motor, and the generator outputs torque in the same direction as the engine rotation. Thus, the inertia of the generator rotor is apparently reduced. Therefore, even if a speed increaser is provided between the engine and the generator, vibration or the like does not occur or is reduced.

When stopping the engine, the generator is operated as a motor to reduce the rotational energy of the engine. For example, a torque is output from the generator in a direction opposite to the rotation of the engine, or rotational energy is consumed as heat by the winding resistance of the generator. Thus, the inertia of the generator rotor is apparently reduced. Therefore,
Even if a speed increaser is provided between the engine and the generator, no vibration or the like is generated or reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an SHV according to an embodiment of the present invention.
Is shown. In this embodiment, an engine 10 having a starter 12 as an engine
Is used, and the mechanical output of the engine 10 is transmitted to the generator 16 via the gearbox 14. Generator 1
Reference numeral 6 denotes a three-phase AC generator, whose power output is rectified by a generator inverter 18 and supplied to a main battery 20 and a motor inverter 22. The motor inverter 22 converts the power output of the generator 16 supplied via the generator inverter 18 and the discharge output supplied from the main battery 20 into three-phase AC power, and supplies the three-phase AC power to the motor 24. The motor 24 is a motor for driving the vehicle, and is driven by power supply via the motor inverter 22 to generate a driving force of the vehicle. The main battery 20 is charged by the power output of the generator 16 and the regenerative power of the motor 24 in addition to an external power source (not shown).

In this embodiment, an EV-ECU 26 and a generator ECU 2 serve as electronic control units (ECUs).
8 are provided. The EV-ECU 26 inputs an ignition (IG) signal, a starter (ST) signal, an accelerator signal, a brake signal, and the like, and controls the motor inverter 22 according to these. The motor inverter 22 includes a predetermined number of switching elements, and the switching operation of these switching elements converts DC power from the generator inverter 18 or the main battery 20 into three-phase AC power. The EV-ECU 26 controls the output of the motor 24 by controlling the switching operation in the motor inverter 22.

The generator ECU 28 communicates with the EV-ECU 26, and communicates with the generator 16 and the generator inverter 1.
8 is controlled. That is, during normal running, all the switching elements constituting the generator inverter 18 are turned off, the generator inverter 18 is operated as a rectifier circuit, and the field current of the generator 16 is controlled. Here, the engine 10 is connected to a generator 16 via a gearbox 14, and the engine 10 is operated with the throttle fully open (WOT) to ensure good fuel economy and emission. By controlling the field current, the rotation speed of the engine 10 can be controlled. The generator ECU 28 monitors the number of revolutions of the engine 10 in order to control the field current of the generator 16.
Is started, the starter 12 is operated according to the ST signal.

FIG. 2 shows a detailed configuration of a main part of this embodiment, particularly, a detailed configuration of a generator inverter 18 and the like.

As shown in FIG. 1, the generator inverter 18 has a configuration in which six power transistors Tr1 to Tr6 and diodes D1 to D6 are bridge-connected. The generator inverter 18 is connected to the generator EC.
Each power transistor Tr1 according to a command from U28
A switching control unit 30 for controlling the switching operation of Tr6.

Generator ECU 28 normally issues a command to switching control unit 30 to supply power transistor Tr1
To turn off all Tr6. In this state, the generator inverter 18 becomes a rectifying bridge composed of diodes D1 to D6. Accordingly, the power output of the generator 16 is rectified by the generator inverter 18 and the main battery 2
0 and the motor inverter 22 side. On the other hand, the generator ECU 28 controls the on / off duty of the transistor Tr7 based on the communication result with the EV-ECU 26 and while monitoring the rotation speed Ne of the engine 10. The transistor Tr7 is a transistor for controlling the field current If supplied to the generator 16. The generator ECU 28 controls the rotation speed of the engine 10 and thus the power output of the generator 16 by performing such control.

This embodiment is characterized in that the engine 10
The operation of the generator ECU 28 when starting or stopping the power supply and the configuration of the generator inverter 18 suitable for this operation. FIG. 3 shows the flow of the operation of the generator ECU 28 in this embodiment, in particular, the operation when starting and stopping the engine 10.

As shown in this figure, the generator ECU 2
8 first determines whether or not the IG signal is on (100). When the IG signal is on, the generator ECU 28 further determines whether or not the ST signal is on (101). Until the ST signal turns on, the generator E
The CU 28 repeats Step 101.

When the ST signal is turned on, the generator ECU 28
Gives a command to the switching controller 32 to operate the generator 16 as a motor (102). That is, in a state where the ST signal is on and the engine 10 can be regarded as being started by the starter 12, the generator ECU
28 gives a command to the switching control unit 30 so that the generator inverter 18 operates as an inverter and the output torque of the generator 16 becomes a torque in the same direction as the rotation speed of the engine 10. Switching control unit 30
Correspond to the power transistors Tr1 to Tr
6 is switched. Therefore, in this state, the generator 16 operates as a motor that assists the starter 12. As a result, the inertia of the rotation system of the engine 10, that is, the rotation system including the rotor of the generator 16, etc., becomes apparently small. Therefore, when the engine 10 starts, its rotation speed passes through the resonance frequency of the rotation system. Also, no vibration or rattle is generated in the backlash portion or the like of the speed increasing device 14. Note that reference numeral 3 in FIG.
The rotation sensor indicated by 2 is a sensor that detects the rotor position of the generator 16. When executing the step 102 and the like, the generator ECU 28 gives a command to the switching control unit 30 so that the power transistors Tr1 to Tr6 are switched in synchronization with the rotor position detected by the rotation sensor 32.

The generator ECU 28 monitors the rotational speed Ne to the engine 10 while executing step 102. If the engine speed Ne does not exceed the predetermined value Ne2, the generator ECU 28 determines in steps 101 and 102
(103). Here, Ne2 is set to a value sufficiently higher than the resonance frequency of the rotating system of the engine 10. For example, when the resonance frequency of the rotation system of the engine 10 is 400 rpm, Ne2 is set to a value such as 500 rpm. Therefore, by executing step 103, it is possible to know whether or not the engine speed Ne has already become sufficiently high and has exceeded the resonance frequency of the rotation system.

In step 103, the engine speed N
e exceeds the predetermined value Ne2, the generator E
The CU 28 gives a command to the switching control unit 30 to turn off all the power transistors Tr1 to Tr6 (104). After that, the generator ECU 28 controls the generator 16 according to a normal algorithm (105). The control executed in step 105 is described in, for example, Japanese Patent Application Laid-Open No. 5-141290 which has been previously proposed by the present applicant.
Please refer to the disclosure content of Japanese Patent Publication No. During normal running, since the IG signal is on, the ST signal is off, and the engine speed Ne exceeds the predetermined value Ne2, the operation of step 105 is repeatedly performed.

Thereafter, when the IG signal is turned off (10
0), the generator ECU 28 determines whether or not the engine speed Ne has become equal to or less than a predetermined value Ne1 (106). This value Ne1 is set to a value sufficiently higher than the resonance frequency of the rotation system of the engine 10, for example, 500 rpm if the resonance frequency is 400 rpm. That is, the determination in step 106 is a determination as to whether or not the engine speed Ne has decreased after the IG signal has been turned off and has approached the resonance frequency. While Ne> Ne1 is satisfied in step 106, the operation of step 100 is repeated,
When Ne ≦ Ne1, the generator ECU 28 executes step 107.

In step 107, the generator ECU
Reference numeral 28 denotes the switching control unit 3 so that the generator inverter 18 operates as an inverter and the output torque of the generator 16 becomes a torque in a direction opposite to the rotation of the engine 10.
Give command to 0. As a result, the inertia of the rotor of the generator 16 is apparently reduced, so that the occurrence of vibrations and the like in the gearbox 14 and the like is prevented or reduced. Such control is repeatedly performed until the engine speed Ne becomes sufficiently small, that is, until the engine speed Ne becomes equal to or less than the predetermined value Ne3 (108). This value N
e3 is a value sufficiently smaller than the resonance frequency, for example, 50r
pm. N in step 108
When e ≦ Ne3 holds, the operation of the generator ECU 28 returns to step 100.

As described above, according to the present embodiment, when starting and stopping the engine 10, the generator 16 is operated as a motor at least near the resonance frequency of the rotating system of the engine 10, and Since the torque is generated in the same or opposite direction as the rotation, the inertia of the rotor of the generator 16 constituting the rotation system of the engine 10 is apparently reduced. Thus, the gearbox 1
4 and the like are prevented or reduced, and a more comfortable traveling environment is obtained.

The present invention is not limited to the configurations shown in FIGS. The present invention can also be applied to, for example, a hybrid electric vehicle that can open and close a mechanical connection between the generator 16 and the motor 24, a so-called SPHV or the like. Further, in step 101, the on / off state of the ST signal is determined. Alternatively, it may be determined whether the engine speed Ne has approached the resonance frequency. However, it is preferable to determine the ON / OFF state of the ST signal in order to accurately determine whether or not the engine is at the start. Further, the value of the torque generated in steps 102 and 107 can be appropriately determined by design. Further, in step 107, the generator 1
6, the torque in the direction opposite to the rotation of the engine 10 is generated, but the torque may be in the same direction. In this case, since the rotational energy of the engine 10 needs to be consumed as heat by the winding resistance of the generator 16, it is necessary to set the output torque in step 107 to a value that allows such energy consumption. Step 106 can be omitted.

[0027]

As described above, according to the present invention,
When the engine is started, the generator operates as a motor and the generator outputs torque in the same direction as the engine rotation, so even if a gearbox is provided between the engine and the generator, vibration etc. will occur. As a result, a more comfortable driving environment can be realized.

Further, according to the present invention, when the engine is stopped, it operates as a motor to reduce the rotational energy of the engine. Therefore, even if a speed-increasing gear is provided between the engine and the generator, the vibration is reduced. As a result, a more comfortable driving environment can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of an SHV according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a main configuration of the embodiment.

FIG. 3 is a flowchart showing a flow of an operation of a generator ECU in the embodiment.

[Explanation of symbols]

Reference Signs List 10 engine 12 starter 14 speed increaser 16 generator 18 generator inverter 24 motor 28 generator ECU 30 switching control unit 32 rotation sensor Tr1 to Tr6 power transistor D1 to D6 diode Ne engine rotation speed Ne1, Ne2, Ne3 of generator Threshold for motoring control execution conditions

Claims (2)

(57) [Claims] 1. A hybrid electric vehicle including an engine started by a starter, a generator driven by a mechanical output of the engine, and a motor driven by a power output of the generator, controls the generator. In the power generation control device, the inertia of the rotation system of the engine including the rotor of the generator is reduced.
Means for operating the generator as a motor when the engine is started by the starter to generate torque in the same direction as the engine rotation, and means for operating the generator as a generator after the engine is started, so that the engine is started by the starter. A power generation control device, comprising: 2. A power generation control device for controlling a generator, which is used in a hybrid electric vehicle including an engine, a generator driven by a mechanical output of the engine, and a motor driven by a power output of the generator. A power generation control device comprising: means for operating a generator as a generator before stopping the engine; and means for operating the generator as a motor when stopping the engine to reduce rotational energy of the engine.