JPH08126115A - Power generation controller of hybrid electric automobile - Google Patents

Abstract

PURPOSE: To prevent or decrease of the vibration and the like in a speed up gear provided between an engine and a generator. CONSTITUTION: When an engine is started (100, 101), a generator is operated as a motor (102) until an engine speed Ne becomes sufficiently higher then the resonant frequency of the rotary system of the engine (103). When the engine is stopped (100), the generator is operated as a motor (107) until the engine speed Ne becomes sufficiently lower than the resonant frequency (108). Since the inertia of the rotor of the generator apparently becomes smaller by the controls of the steps 102 and 107, the conspicuous vibration in the speed up gear does not occur.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle provided with 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 thereof.

[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 for the vehicle. The HV includes a series HV (SHV) and a parallel HV (PHV). In the former case, the generator drives by the mechanical output of the engine, and the vehicle running motor is driven by using the power generation output of the generator and the discharge output of the vehicle-mounted battery. In the latter case, when the vehicle is driven by using the mechanical output of the engine, the excess / deficiency of the engine output is assisted or absorbed by the motor / generator.

In SHV, a speed increasing gear is usually provided between the engine and the generator. The gearbox is a mechanism for increasing the rotation speed to a value suitable for the generator when transmitting the mechanical output of the engine to the generator. By using such a mechanism, the rated speed of the generator can be made sufficiently high, and the generator can be downsized.

[0004]

By the way, the power transmission system from the engine to the generator is usually not provided with a clutch mechanism. Therefore, the rotating system of the engine includes the rotor of the generator and the like. The resonance frequency of this rotary system is usually the idle speed of the engine (eg 700 rpm).
It becomes a lower frequency (for example, 400 rpm).

When the engine is started, it is necessary to increase the engine speed from 0 rpm to the idle speed, so that the above resonance frequency must be passed. Here, the inertia of the rotor of the generator is large, and the gearbox is provided, so that vibration and rattling noise are generated from the backlash portion of the gears constituting the gearbox due to resonance. When stopping the engine, it is necessary to lower the engine speed from the idle speed to 0 rpm.
After all, it has no choice but to pass the above-mentioned resonance frequency. In this case, although the engine does not serve as a vibration source, normally, a plurality of cylinders provided as cylinders act as mechanical resistance, and similarly resonance occurs.

The present invention has been made to solve the above problems, and controls the generator when starting and stopping the engine to cause resonance of a rotating system including a rotor of the generator. The purpose is to prevent vibration and reduce vibration and the like.

[0007]

In order to achieve such an object, a power generation control device according to the present invention operates a generator as a motor when starting an engine to generate a torque in the same direction as the engine rotation. And a means for operating the generator as a generator after the engine is started.

The power generation control device according to the present invention comprises means for operating the generator as a generator before the engine is stopped, and means for operating the generator as a motor to reduce the rotational energy of the engine when the engine is stopped. It is characterized by including.

[0009]

In the present invention, when the engine is started, the generator is operated as a motor and the generator outputs torque in the same direction as the engine rotation. This apparently reduces the inertia of the rotor of the generator. Therefore, even if a speed increaser is provided between the engine and the generator, vibration or the like is eliminated or reduced.

When stopping the engine, the generator is operated as a motor to reduce the rotational energy of the engine. For example, the generator outputs a torque in the direction opposite to the engine rotation, or the rotational energy is consumed as heat by the winding resistance of the generator. This apparently reduces the inertia of the rotor of the generator. Therefore,
Even if a speed increaser is provided between the engine and the generator, vibration or the like does not occur or is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment 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.
The system configuration of is shown. In this embodiment, an engine 10 including 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, the power generation output of which is rectified by the generator inverter 18 and then supplied to the main battery 20 and the motor inverter 22. The motor inverter 22 converts the power generation output of the power generator 16 supplied via the power generator inverter 18 and the discharge output supplied from the main battery 20 into three-phase AC power, and supplies this 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 an external power source (not shown), the power generation output of the generator 16 and the regenerative power of the motor 24.

In this embodiment, the EV-ECU 26 and the generator ECU 2 are used as an electronic control unit (ECU).
8 are provided. The EV-ECU 26 inputs an ignition (IG) signal, a starter (ST) signal, an accelerator signal, a brake signal, etc., and controls the motor inverter 22 in accordance with these signals. The motor inverter 22 is composed of a predetermined number of switching elements, and the switching operation of these switching elements converts the 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 of the motor inverter 22.

The generator ECU 28 communicates with the EV-ECU 26, and at the same time, the generator 16 and the inverter 1 for the generator.
Control eight. That is, during normal traveling, all the switching elements forming the generator inverter 18 are turned off to operate the generator inverter 18 as a rectifier circuit and control the field current of the generator 16. Here, the engine 10 is connected to a generator 16 via a speed increaser 14, and since the engine 10 is operated at full throttle (WOT) to ensure good fuel consumption and emission, The rotation speed of the engine 10 can be controlled by controlling the field current. The generator ECU 28 monitors the rotation speed of the engine 10 in order to control the field current of the generator 16, and also the engine 10
When starting the engine, the starter 12 is operated according to the ST signal.

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

As shown in this figure, the generator inverter 18 has a structure in which six power transistors Tr1 to Tr6 and diodes D1 to D6 are bridge-connected. In addition, the generator inverter 18 is a generator EC
Each power transistor Tr1 according to the command from U28
A switching control unit 30 that controls the switching operation of Tr6 is provided.

The generator ECU 28 normally gives a command to the switching control unit 30 to supply the power transistor Tr1.
~ Turn off all Tr6. In this state, the generator inverter 18 becomes a rectifying bridge composed of the diodes D1 to D6. Therefore, the power generation 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. By performing such control, the generator ECU 28 controls the rotation speed of the engine 10 and thus the power generation output of the generator 16.

This embodiment is characterized by the engine 10
2 is an operation of the generator ECU 28 when starting or stopping the engine and a 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, particularly the operation of 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 the ST signal is on (101). Until the ST signal turns on, 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 control section 32 to operate the generator 16 as a motor (102). That is, in a state where the ST signal is on and therefore the engine 10 can be regarded as being started by the starter 12, the generator ECU
Reference numeral 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
Are the power transistors Tr1 to Tr1 according to this command.
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 is apparently small. Therefore, when the engine 10 is started, it is assumed that the rotation speed has passed the resonance frequency of the rotation system. In addition, vibration and rattling noise do not occur in the backlash portion of the speed increaser 14. Incidentally, 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 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 executes step 102 while monitoring the rotation speed Ne of the engine 10. If the engine speed Ne does not exceed the predetermined value Ne2, the generator ECU 28 performs steps 101 and 102.
Is continuously executed (103). Here, Ne2 is set to a value sufficiently higher than the resonance frequency of the rotation system of the engine 10. For example, when the resonance frequency of the rotating system of the engine 10 is 400 rpm, Ne2 is set to a value such as 500 rpm. Therefore, by executing step 103, it can be known whether or not the engine speed Ne has already become sufficiently high and has exceeded the resonance frequency of the rotating system.

In step 103, the engine speed N
When it is determined that 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). The generator ECU 28 then controls the generator 16 according to a normal algorithm (105). Regarding the control executed in step 105, for example, Japanese Patent Application Laid-Open No. 5-141290 previously proposed by the applicant of the present application.
Please refer to the disclosure contents such as the official gazette. During normal traveling, the IG signal is on, the ST signal is off, and the engine speed Ne exceeds the predetermined value Ne2, so the operation of step 105 is repeatedly executed.

After that, when the IG signal is turned off (10
0), the generator ECU 28 determines whether the engine speed Ne has become equal to or lower 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, a value such as 500 rpm when 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 turned off and the resonance frequency has been approached. While Ne> Ne1 is satisfied in step 106, the operation of step 100 is repeated,
When Ne ≦ Ne1 is satisfied, the generator ECU 28 executes step 107.

In step 107, the generator ECU
28 is a 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 a command to 0. As a result, the inertia of the rotor of the generator 16 is apparently reduced, so that the occurrence of vibration or the like in the speed increaser 14 or the like is prevented or reduced. Such control is repeatedly executed until the engine speed Ne becomes sufficiently small, that is, 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
It is set to a value of about pm. N in step 108
When e ≦ Ne3 is satisfied, the operation of the generator ECU 28 returns to step 100.

As described above, according to the present embodiment, when the engine 10 is started and stopped, the generator 16 is operated as a motor at least in the vicinity of the resonance frequency of the rotation system of the engine 10 to cause the engine 10 to operate. Since the torque is generated in the same direction as or in the opposite direction to the rotation, the inertia of the rotor of the generator 16 forming the rotating system of the engine 10 is apparently small. As a result, the speed increaser 1
Generation of vibration and the like in 4 and the like is prevented or reduced, and a more comfortable traveling environment can be obtained.

The present invention is not limited to the configurations shown in FIGS. 1 and 2. The present invention can be applied to, for example, a hybrid electric vehicle capable of opening and closing the mechanical connection between the generator 16 and the motor 24, so-called SPHV or the like. Further, in step 101, the ON / OFF state of the ST signal is determined, but instead of this, it may be determined whether or not the engine speed Ne approaches 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 starting. 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
Although the torque generated in the direction opposite to the rotation of the engine 10 is generated by 6, the torque may be generated in the same direction. In that case, since the rotational energy of the engine 10 needs to be consumed as heat by the winding resistance of the generator 16, the output torque in step 107 needs to be set to a value that allows such energy consumption. Also, 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 installed between the engine and the generator, vibration etc. will occur. As a result of no occurrence or reduction, a more comfortable traveling environment can be realized.

Further, according to the present invention, when the engine is stopped, it is operated as a motor to reduce the rotational energy of the engine. Therefore, even if a speed increaser is provided between the engine and the generator, the vibration is generated. As a result, the more comfortable traveling environment can be realized.

[Brief description of 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 showing a main configuration of the present embodiment.

FIG. 3 is a flowchart showing a flow of operations of a generator ECU in the present embodiment.

[Explanation of symbols]

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

Claims (2)

[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 generated output of the generator, and controlling the generator. In the power generation control device, a means for operating the generator as a motor when starting the engine to generate a torque in the same direction as the engine rotation, and a means for operating the generator as the generator after the engine is started. A power generation control device characterized by: 2. A power generation control device 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 generated output of the generator, and controlling the generator. A power generation control device comprising: a unit that operates the generator as a generator before the engine is stopped; and a unit that operates the generator as a motor to reduce the rotational energy of the engine when the engine is stopped.