JP2004147362A - Power generation system for vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power generation system for a vehicle capable of restricting power generation amount even under non-exciting control state where field current passes. <P>SOLUTION: This power generation system comprises an alternator (A) equipped with a rotor and a stator, a voltage regulator (V) for controlling field current passed through a rotor coil (Rc), an engine for the rotation of the rotor, and an ECU for controlling the engine. The engine ECU is operated by restricting the rotational speed of the engine under a prescribed restricted rotational speed when the field current is uncontrollable and the non-exciting control state is kept where the field current continues to pass. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicular power generation system provided with an alternator or an alternator such as a motor / generator (M / G) mounted on a vehicle and a control method thereof.
[0002]
[Prior art]
2. Description of the Related Art A vehicle is conventionally provided with a power generation device for supplying power to an electric load and a battery. An alternator generates electricity for a normal vehicle running on an engine, a generator for a series hybrid vehicle, and a motor generator (M / G) for a parallel hybrid vehicle. Each of these AC power generators is driven by an engine, and the amount of power generation is usually controlled by controlling the field current, so that stable power supply is performed. For example, in the case of an alternator, the control of the field current is performed by a voltage regulator including a semiconductor switching element such as a transistor. This regulator performs a duty control for interrupting the field current in accordance with the amount of power generated by the AC power generator and the battery voltage. For example, when the battery voltage increases due to overcharging, the field current is cut off to suppress the power generation amount, and when the battery voltage decreases, the field current flows to increase the power generation amount.
[0003]
However, the AC power generator installed in the vehicle has severe operating environment such as temperature and vibration, so the switching element used for the regulator etc. may break down or other wiring parts may be short-to-power or ground-fault. Is also conceivable. In such a case, the field current is not controlled by the regulator or the like (excitation is not controlled), and the power may not be generated, or conversely, the generated power may be excessive and the overload may be applied to the electric load.
However, in the case of a failure in which the field current does not flow and the power is not generated, the warning light in the driver's seat is turned on and the driver can easily detect the abnormality. Further, even if power generation is stopped, power is supplied from the battery for a while, so that the vehicle can be moved and the like, and limp-home traveling to a safe place can be performed.
However, in the case of a failure in which the field current is released, the amount of power generation continues to increase, so that the battery is in an overcharged state, and an overvoltage is applied to the electric load, which may cause a secondary failure. is there.
Therefore, even when the latter type of failure occurs, for example, in the case where a regulator fails and certain conditions are satisfied, a power generation control device that cuts off a field current via a relay is disclosed in Japanese Patent Application Laid-Open No. 5-344797. No. 5,009,045. This prevents application of an overvoltage to the electric load even at the time of failure.
[0004]
[Patent Document 1]
JP-A-5-344797
[Problems to be solved by the invention]
However, in the method disclosed in the above publication, a dedicated relay or the like must be newly provided, which increases the cost. In addition, when a failure occurs, evacuation traveling is possible, but traveling over long distances is difficult, and it is not possible to travel from the failure location to home or a repair shop by itself.
The present invention has been made in view of such circumstances. In other words, an object of the present invention is to provide a vehicular power generation system capable of ensuring sufficient power generation by an AC power generation device and enabling sufficient traveling even when a failure occurs in which a field current continues to flow, and a control method thereof.
[0006]
Means for Solving the Problems and Effects of the Invention
Therefore, the present inventors have conducted intensive research to solve this problem, and as a result of repeated trial and error, focused on the fact that the amount of power generated by the AC power generator depends on the engine speed when the field current continues to flow and the excitation is not controlled. Then, they came up with the idea of adjusting the amount of power generation by controlling the engine speed, and completed the present invention.
(Vehicle power generation system)
That is, the vehicle power generation system of the present invention includes a rotor having a field coil that rotates together with the main shaft to form a field and a stator that is disposed around the rotor and has at least three-phase armature coils. An AC power generator in which the rotor is driven and rotated to generate AC by the armature coil; a power generation controller capable of controlling a field current flowing through the field coil to adjust a power generation amount of the AC generator; A rectifier that converts the AC power generated by the AC generator into DC power, a storage battery that stores the converted DC power, an engine that rotationally drives the rotor of the AC generator, and controls the engine. An engine control device, wherein the engine control device cannot adjust the field current by the power generation control device. Is at the flow continues excitation uncontrolled, characterized in that it comprises a rotational speed limiting means for driving and limiting the rotation speed of the engine below a predetermined limit rotational speed (claim 1).
[0007]
According to the present invention, when the above-mentioned excitation non-control state is established, the engine speed is limited by the speed limiting means. If the vehicle is driven with the engine speed limited to a predetermined range, the amount of power generated by the AC power generator does not become excessive even when the field current continues to flow, so that overvoltage is applied to the electric load or the battery is overcharged. Are also suppressed and prevented.
Further, even if the engine speed is limited by the rotation speed limiting means, the vehicle can travel sufficiently as long as the normal limp-home mode. In addition, even in that case, a sufficient power generation amount can be obtained from the AC power generation device depending on the setting.
In this way, even when the power generation control device or the like that adjusts the power generation amount fails and the excitation is not controlled, the vehicle can continue to travel, and the vehicle can travel from the failure location to home or a repair shop by itself. It is also possible to go.
The vehicle power generation system that performs such control can be easily achieved by, for example, changing the program of the engine control device. Therefore, a so-called fail-safe cost can be reduced as compared with the case where a protection circuit or the like is provided.
[0008]
(Control method of vehicle power generation system, etc.)
The present invention can be understood not only as the above-described power generation system for a vehicle but also as a control method for performing the above-described control, and further, an AC power generation device, a power generation control device, or an engine control device based on the control method. It can also be grasped.
[0009]
By the way, the non-excitation control state in the present invention can be easily detected by the battery voltage, the voltage across the field coil (field coil), the current amount of the field coil, and the like. In order to perform such detection, a detecting means including a shunt resistor and a current sensor may be separately incorporated. However, a detecting circuit or a monitoring circuit is previously incorporated in an IC or the like of the power generation control device, and the detection circuit is not excited. It suffices to use control state detection means.
[0010]
The recognition of the non-excitation state by the engine control unit is performed, for example, by transmitting a detection signal to the engine control unit when the power generation control unit detects the non-excitation state, and receiving a failure detection signal by the engine control unit. You can do it. Of course, depending on the detection method of the excitation non-control state, the engine control device may recognize the excitation non-control state without the intervention of the power generation control device.
[0011]
The AC generator of the present invention may be an alternator that also serves as a starter, a generator mounted on a hybrid vehicle, a generator / motor (motor generator: M / G), or the like, in addition to a normal alternator. This AC power generator is not limited to a synchronous machine, and may be an induction machine as long as it can adjust the amount of power generation by controlling the field current.
Examples of the case where the above-mentioned non-excitation control state occurs include an open failure (insulation failure) and a close failure (short circuit breakdown) of a switching element for controlling a field current, a power supply ground fault, a ground fault, and the like of a field current circuit. In either case, the excitation non-control state is determined by the circuit configuration.
[0012]
The engine speed limiting means sets the engine speed at or below the engine speed. The engine speed is appropriately determined based on the output of the AC generator, the reduction ratio, the electric load, and the like. The limit rotation speed is preferably within a range in which the vehicle can normally travel. For example, an engine with an idle rotation of 700 to 800 rpm and a limit rotation speed of 2000 rpm or the like are set.
Even when the engine speed is limited to less than the limit speed in the non-excitation control state, the vehicle must be equipped with an automatic transmission with a torque converter, a belt type, a toroidal type, etc. It is preferable to provide an automatic transmission without permission.
In this case, even if the rotational speed limit is set to a relatively low rotational speed, a sufficient torque can be obtained in a low speed range, and traveling within a general speed is also possible.
[0013]
Based on the above, the vehicle power generation system and the control method thereof according to the present invention are also suitable as follows.
The non-excitation control state may be detected when the voltage of the storage battery (battery voltage) or the output voltage of the AC generator becomes equal to or higher than a predetermined value.
The non-excitation control state may be detected when the field current becomes equal to or more than a predetermined value. In this case, it is preferable that the predetermined value of the field current is stored as map information associated with the rotation speed of the AC power generator (claim 5).
It is preferable that the engine is operated with the number of revolutions limited to a range in which the battery voltage, the output voltage of the AC generator or the field current value does not exceed a predetermined value (claim 6).
[0014]
Further, the engine includes an idle stop control device that stops the engine in an idle state and restarts the engine when the vehicle starts. The AC generator is an AC motor generator that also restarts the engine, and the excitation non-control state is detected. At this time, it is more preferable that the stop and restart of the engine in the idle state by the idle stop control device are prohibited to suppress the discharge of the storage battery (claim 7).
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in more detail with reference to embodiments.
FIG. 1 is a block diagram showing an entire vehicle power generation system S according to an embodiment of the present invention.
The vehicle power generation system S includes an engine, an engine control device that controls the engine, an AC power generation device that is driven by the engine, a power generation control device that adjusts the power generation amount of the AC power generation device, and power generation by the AC power generation device. A rectifier that converts the AC power into DC power, and a storage battery that is charged by the DC power.
[0016]
More specifically, the engine referred to in the present embodiment is a reciprocating gasoline engine, the AC generator includes a rotor and a stator of an alternator A, the engine controller is an engine ECU, and the generator controller is a voltage regulator V. Yes, the rectifier is a rectifier R and the storage battery is a battery B. A drive belt is suspended between a crank pulley attached to the crankshaft of the engine and a pulley attached to the main shaft of the alternator A, and the alternator A is driven by the engine by the drive belt. Further, the voltage regulator V and the engine ECU can communicate with each other. When the voltage regulator V detects a non-excitation control state described later, a failure detection signal is transmitted to the engine ECU, and the engine ECU receives the detection signal. Then, the excitation non-control state is recognized.
[0017]
Next, FIG. 2 shows an overall circuit diagram of an alternator A in which a rectifier R and a voltage regulator V are incorporated in addition to the rotor and the stator.
A rotor coil (field coil) Rc is wound around the rotor of the alternator A, and a stator coil (armature coil) Sc for three phases is wound around a stator surrounding the outer periphery of the rotor. Then, when the rotor coil Rc to which the field current is supplied via the slip ring rotates inside the stator coil Sc, the stator coil Sc generates AC power. The generated AC power is full-wave rectified by a rectifier R including a neutral point diode, and DC power is supplied to a battery B and various electric loads.
[0018]
By the way, since the required amount of power differs depending on the driving condition of the vehicle, it is necessary to adjust the amount of power generation accordingly. This adjustment is performed by controlling the field current flowing from the voltage regulator V to the rotor coil Rc. More specifically, the IC of the voltage regulator V monitors the voltage (battery voltage) of the terminal B, and turns on / off the transistor Tr1 so that the voltage falls within a predetermined range, so that the field flowing through the rotor coil Rc Intermittently controls the current.
By the way, considering the case where the transistor Tr1 fails, the field current control (excitation current control) of the rotor coil Rc is disabled. Here, considering the case where the transistor Tr1 has an open failure (insulation failure), the field current does not flow through the rotor coil Rc, so that no power is generated. When the IC of the voltage regulator V detects this state by an increase in the voltage at the F terminal or the like, the transistor Tr2 is turned on, and the charge lamp C is turned on. Thereby, the driver recognizes that the alternator A is out of order and that no power is being generated. Then, the driver performs limp-home traveling using the battery B as a power source as appropriate.
[0019]
On the other hand, when the short-circuit fault occurs in the transistor Tr1, the field current continues to flow through the rotor coil Rc, the voltage applied to the electric load increases, or the battery is overcharged. When the IC of the voltage regulator V detects this state (excitation non-control state) from an increase in the B terminal voltage or a decrease in the F terminal voltage (detection step), it transmits a failure detection signal to the engine ECU (transmission step). The engine ECU that has received the failure detection signal operates the engine using the rotation speed limiting means with the preset rotation speed as an upper limit (rotation speed limiting step).
The rotation speed limiting means may change the fuel injection signal to zero when the engine rotation speed reaches the rotation speed limit, or change the ignition signal to a non-ignition state, for example. Is what you do. Further, the rotation speed limiting means may temporarily reset the operating rotation speed of a limiter provided in a normal engine to the limited rotation speed.
[0020]
As described above, according to the vehicle power generation system S of the present embodiment, the fail-safe of the alternator A can be easily performed. Further, a conventional voltage regulator or the like can be used with almost no change. Further, by providing the fail-safe, the fail-safe protection circuit provided conventionally can be simplified or omitted, and the cost can be reduced accordingly.
In the above embodiment, the case where the present invention is applied to an alternator has been described. However, the present invention is not limited to this, and the present invention can be applied to a motor generator or a regenerative generator mounted on a hybrid vehicle or the like.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the overall configuration of a vehicle power generation system according to an embodiment of the present invention.
FIG. 2 is a circuit diagram of the alternator of the embodiment.
[Explanation of symbols]
S vehicle power generation system A alternator V voltage regulator (power generation control device)
R rectifier (rectifier)
B battery (storage battery)

Claims (7)

A rotor having a field coil that rotates together with the main shaft to form a field, and a stator disposed around the rotor and having at least three-phase armature coils, the rotor being driven and rotated to An alternating-current generator that generates alternating current with a child coil;
A power generation control device that can control a field current flowing through the field coil to adjust a power generation amount of the AC power generation device;
A rectifier that converts AC power generated by the AC power generator into DC power;
A storage battery for storing the converted DC power,
An engine that rotationally drives the rotor of the AC power generator;
An engine control device for controlling the engine;
A vehicle power generation system comprising:
The engine control device operates while limiting the field current by the power generation control device and in a non-excitation control state in which the field current continues to flow, by limiting the engine speed to a predetermined speed limit or lower. A power generation system for a vehicle, comprising: a rotation speed limiting unit. A rotor having a field coil that rotates together with the main shaft to form a field, and a stator disposed around the rotor and having at least three-phase armature coils, the rotor being driven and rotated to An alternating-current generator that generates alternating current with a child coil;
A power generation control device that can control a field current flowing through the field coil to adjust a power generation amount of the AC power generation device;
A rectifier that converts AC power generated by the AC power generator into DC power;
A storage battery for storing the DC power;
An engine that rotationally drives the rotor of the AC power generator;
An engine control device for controlling the engine;
A method for controlling a vehicle power generation system comprising:
The engine control device operates while limiting the field current by the power generation control device and in a non-excitation control state in which the field current continues to flow, by limiting the engine speed to a predetermined speed limit or lower. A method for controlling a vehicle power generation system, comprising: 3. The vehicle power generation system according to claim 1, wherein the non-excitation control state is detected when a voltage of the storage battery or an output voltage of the AC power generation device becomes a predetermined value or more. 4. The power generation system for a vehicle according to claim 1 or 2, wherein the non-excitation control state is detected when the field current exceeds a predetermined value. The vehicle power generation system according to claim 4, wherein the predetermined value of the field current is stored as map information associated with a rotation speed of the AC power generation device. 3. The vehicle power generation system according to claim 1, wherein the engine is operated with the number of revolutions limited to a range in which a voltage of the storage battery does not exceed a predetermined value, or a control method thereof. 4. Further, an idle stop control device that stops the engine in an idle state and restarts the engine at the time of starting is provided.
The AC generator is an AC motor generator that also performs the restart,
3. The vehicle according to claim 1, wherein when the excitation non-control state is detected, the stop and restart of the engine in the idle state by the idle stop control device are prohibited to suppress discharge of the storage battery. 4. Power generation system or its control method.

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