JP2010167991A - Electronic control unit and exciting current control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic control unit and an exciting current control method for obtaining proper power generation amount while restraining a temperature rise. <P>SOLUTION: The electronic control unit 100 connected to an alternator 11 that controls the power generation amount by exciting current supplied by switching on or off a switching element 25 with a PWM signal through a communication line 15 includes a receiving means 14 receiving current value information including a current value of the exciting current and duty ratio information including duty ratio of the PWM signal when the temperature of the alternator 11 is higher than the predetermined value, a calculation means 42 calculating the current value for limiting the exciting current by multiplying the duty ratio regarding an ability set value that is smaller than the duty ratio to the current value, and transmitting means 14, 42 transmitting information on the current value for limiting including the current value for limiting and request information requesting to limit the exciting current to the current value for limiting or less to the alternator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic control unit and the like connected to an alternator, and more particularly to an electronic control unit and an excitation current control method for limiting the amount of power generated when the alternator is at a high temperature.

  An alternator is mounted on the vehicle to supply electric power to various vehicle electric loads mounted on the vehicle and to charge the battery. The alternator generates a magnetic field by supplying an exciting current to the rotor coil, and generates electric power by taking out the current from the stator coil as the magnetic field rotates in the stator coil as the engine rotates.

  By the way, the alternator has a protection function that automatically stops for protection of circuits and the like, that is, prohibits power generation when the temperature becomes high. For this reason, the alternator detects the temperature with a thermistor or the like. However, if power generation is stopped immediately because of high temperature, there is a disadvantage in that the remaining battery capacity decreases because the vehicle electrical load of the vehicle uses power. For such inconvenience, a technique for continuing power generation while suppressing the temperature rise of the thermistor has been considered (for example, see Patent Documents 1 and 2).

  Patent Document 1 discloses an alternator that executes control to reduce the excitation current when the temperature of the alternator reaches a predetermined value or more. Since the power generation amount of the alternator changes according to the magnitude of the magnetic field and the heat generation amount changes according to the power generation amount, when the excitation current is reduced, the power generation amount can be reduced and the temperature rise can be suppressed. Here, as a control for reducing the excitation current, a technique for reducing the field duty ratio of a PWM signal for turning on / off a switching element connected in series to the rotor coil is described.

Similarly, Patent Document 2 discloses an alternator that reduces the excitation current when the ambient temperature exceeds a predetermined value. However, Patent Document 2 describes a specific configuration for reducing the excitation current. Not.
JP 2006-149131 A Japanese National Patent Publication No. 3-502873

  However, there is a problem that it is difficult to appropriately control the power generation amount only by reducing the excitation current as in Patent Document 1 or 2. For example, when cooling is prioritized in determining the field duty ratio, the amount of power generation is insufficient, and when power generation is prioritized, it is difficult to suppress temperature rise. That is, when the alternator becomes hot, control is required to ensure an appropriate amount of power generation while suppressing temperature rise.

  Further, since the excitation current does not correspond to the power generation amount on a one-to-one basis (for example, even if the excitation current is constant, the power generation amount is not always constant). The amount cannot be controlled properly.

  In view of the above problems, an object of the present invention is to provide an electronic control unit and an excitation current control method that secure an appropriate amount of power generation while suppressing a temperature rise.

  In view of the above problems, the present invention provides an alternator that controls power generation by an excitation current that is supplied by turning on or off a switching element with a PWM signal, and an electronic control unit that is connected by a communication line. When the temperature is high, the receiving means for receiving the current value information including the current value of the excitation current and the duty ratio information including the duty ratio of the PWM signal, and the ratio of the duty ratio to the capacity setting value that is smaller than the duty ratio The calculation means for calculating the limiting current value of the excitation current by multiplying the current value, the limiting current value information including the limiting current value, and the request information for requesting that the exciting current be limited to the limiting current value or less And transmitting means for transmitting to the alternator.

  It is possible to provide an electronic control unit and an excitation current control method that ensure an appropriate amount of power generation while suppressing a temperature rise.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Outline of power generation control system 100]
FIG. 1 shows an example of a schematic configuration diagram of a power generation control system 100. The power generation control system 100 includes an alternator 11, a control ECU (Electronic Control Unit) 12, and a communication line 15. The alternator 11 has an IC regulator 13, and the IC regulator 13 is connected to the control ECU 12 via a communication line 15.

  The IC regulator 13 monitors the voltage or SOC (State of charge) (hereinafter simply referred to as SOC) of the battery 28, adjusts the electric power generated by the driving force of the engine or motor according to the SOC of the battery 28, and 28. Further, the IC regulator 13 can turn on the charge lamp 17 as to whether or not power generation is in progress, and can display the power generation rate on the meter panel. The IC regulator 13 has a communication unit 32 for communicating with the control ECU 12.

  The communication unit 32 communicates bidirectionally with the communication unit 14 of the control ECU 12 according to a protocol such as LIN (Local Interconnect Network). In this embodiment, since the amount of data to be communicated is not large, a relatively low speed LIN may be used, but a CAN (Controller Area Network) or FlexRay may be adopted in addition to LIN.

  The control ECU 12 calculates a maximum excitation current described later. The control ECU 12 has a computer in which a CPU, RAM, EEPROM, nonvolatile memory, communication unit 14, and input / output interface are connected via an internal bus. The control ECU 12 can be used, for example, as a power control ECU or an engine ECU. However, any ECU can be used as long as it has the communication unit 14 and can communicate with the IC regulator 13, and is mounted on the vehicle exclusively for controlling the alternator 11. An ECU may be used.

An outline of power generation control of the present embodiment will be described.
(1) The IC regulator 13 monitors the temperature of the alternator 11 with the thermistor 22, and transmits a high temperature abnormality signal to the control ECU 12 when the temperature becomes equal to or higher than the threshold value T1.
(2) Further, the control ECU 12 receives from the IC regulator 13 the actually measured excitation current Im that is the actually measured value and the actually measured field duty ratio (hereinafter simply referred to as the actually measured FD _m ) that is the actually measured value.
(3) The control ECU 12 calculates the maximum excitation current I _max from the measured excitation current Im, the measured FD _m , and the set capacity value FD _g . The set capacity value FD _g is an arbitrary capacity value for the maximum power generation capacity of the alternator 11. For example, when the control ECU 12 requests the alternator 11 to generate power with half the maximum power generation capacity, the set capacity value FD _g is 50% (the field duty ratio is a value between 0 and 100%). take). Specifically, the control ECU 12 calculates the maximum excitation current I _max by the following equation.
I _max = Im × FD _g / FD _m (A)
(4) The control ECU 12 transmits the calculated maximum excitation current I _max to the IC regulator 13. At the time of transmission, the control ECU 12 sets a number indicating that the maximum excitation current I _max is included in the LIN communication data ID.
(5) IC regulator 13 that receives the maximum excitation current I _max, the excitation current to control the exciting current to be equal to or less than the maximum excitation current I _max.

According to the equation (A), the value obtained by reducing the measured excitation current Im is set as the maximum excitation current I _{max based on} the ratio between the set capacity value FD _g and the measured FD _m (below 1 when a high temperature abnormality is detected). Can be calculated. Thus, even if the maximum excitation current I _max is calculated, the IC regulator 13 can turn on / off the switching element 25 with the field duty value calculated according to the SOC of the battery 28 as usual. For this reason, the power generation amount instructed by the IC regulator 13 corresponds to the power generation amount required for the vehicle electrical load determined from the SOC of the battery 28 or the like.

However, IC regulator 13, since the exciting current to control the excitation current so as not to exceed the maximum excitation current I _max, the exciting current is smaller than the measured excitation current Im before high temperature abnormality is detected. Therefore, the maximum power generation amount can be secured within a range in which the temperature rise of the alternator 11 can be suppressed. In other words, the alternator 11 can generate power with an optimal power generation amount without stopping power generation when the temperature is abnormal.
In the present embodiment, “suppressing the temperature rise” includes lowering the temperature. Whether the temperature rise continues or the temperature starts to drop when the excitation current is less than or equal to the maximum excitation current I _max can vary depending on the outside air temperature, the engine water temperature, and the like.

[IC regulator 13]
FIG. 2 is an example of a diagram schematically illustrating an example of the configuration of the IC regulator 13. The alternator 11 includes a switching element 25, a resistor 24, a rotor coil 30, a diode 29 connected in parallel with the rotor coil 30, a stator coil 33 that generates a three-phase AC voltage, and a current that flows due to the three-phase AC voltage. A rectifier circuit 34 that rectifies and outputs a direct current and the IC regulator 13 are provided. The output terminal B of the rectifier circuit 34 is connected to the battery 28. In addition to the battery 28, it is also connected to a vehicle electrical load such as an air conditioner. Therefore, charging power is supplied from the output terminal B to the battery 28 and the vehicle electrical load.

  The IC regulator 13 includes a voltage adjustment unit 27 connected to the battery 28, a current detection unit 21 that detects a current flowing through the resistor 24, a thermistor 22 that detects temperature, an overheat prevention unit 23 that is connected to the thermistor 22, and an overheat. An AND circuit 26 to which the output of the prevention unit 23 and the output of the voltage adjustment unit 27 are connected, and a variable current limiter 31 connected in series to the rotor coil 30 are included.

In a state where the high temperature abnormality is not detected, the voltage adjusting unit 27 adjusts the voltage of the charging power of the alternator 11. The voltage adjustment unit 27 detects the SOC of the battery 28, increases the field duty ratio of the PWM signal when the SOC of the battery 28 decreases, and decreases the field duty ratio when the SOC of the battery 28 increases. The relationship between the SOC of the battery 28 and the field duty ratio is determined, for example, in a map. Voltage adjusting unit 27 sends the field duty ratio to the communication unit 32 as FD _m.

  Here, since the AND circuit 26 is always Hi until the temperature of the thermistor 22 exceeds the threshold value T2, the AND circuit 26 transmits the PWM signal in a normal state. Therefore, the switching element 25 is turned on when the PWM signal output from the voltage adjustment unit 27 is Hi, and is turned off when the PWM signal is Low. Therefore, an excitation current corresponding to the field duty ratio flows through the rotor coil 30.

  When the rotor coil 30 rotates in the stator coil 33 with an exciting current flowing through the rotor coil 30, a three-phase alternating current is generated in the U phase, V phase, and W phase of the stator coil 33. The rectifier circuit 34 performs full-wave rectification on the three-phase alternating current and supplies it to the battery 28.

The resistor 24 is connected in series between the emitter of the transistor and the ground. For this reason, the resistor 24 has a current comparable to the current flowing between the emitter and drain of the transistor, that is, the exciting current flowing through the rotor coil 30. Flows. The current detector 21 detects the current flowing through the resistor 24 as the actually measured excitation current Im and sends it to the communication unit 32. Since flows rectangular type current comparable to the PWM signal to the resistor 24, the current detecting section 21 measures the field duty ratio, the measured field duty ratio may be detected as FD _m.

  The overheat prevention unit 23 performs two operations according to the temperature of the alternator 11 detected by the thermistor 22. The first operation is to output a high temperature abnormality signal to the communication unit 32 when the temperature becomes equal to or higher than the threshold value T1. The threshold value T1 is, for example, a temperature that is about 10 to 20% lower than the specification upper limit temperature, and is a temperature that may exceed the specification upper limit temperature if the temperature of the alternator 11 continues to rise. Therefore, the alternator 11 can generate power when the overheat prevention unit 23 outputs a high temperature abnormality signal. The overheat prevention unit 23 continuously sends a high temperature abnormality signal to the communication unit 32 while the temperature detected by the thermistor 22 exceeds the threshold value T1. The communication unit 32 continuously transmits a high temperature abnormality signal to the control ECU 12.

  The second operation is to output a Low signal to the AND circuit 26 when the temperature becomes equal to or higher than the threshold value T2 (> T1). The threshold value T2 is, for example, a temperature slightly lower than the specification upper limit temperature, that is, a temperature immediately before exceeding the specification upper limit temperature. When the signal input from the overheat prevention unit 23 to the AND circuit 26 becomes Low, the AND circuit 26 does not output the PWM signal input from the voltage adjustment unit 27, so that the excitation current flowing through the rotor coil 30 can be cut off.

The variable current limiter 31 operates as follows by comparing the set upper limit current value (maximum exciting current I _max ) with the current flowing through the rotor coil 30.
・ Excitation current ≦ Maximum excitation current I _max : Excitation current is not limited ・ Excitation current> Maximum excitation current I _max : Excitation current is limited to the maximum excitation current I _max or less in this way. 31 can limit the excitation current to a maximum excitation current I _max or less. The communication unit 32 that has received the maximum excitation current I _max from the control ECU 12 sets the maximum excitation current I _max in the variable current limiter 31, so the variable current limiter 31 makes the upper limit of the excitation current flowing through the rotor coil 30 variable. be able to.

Thus, instead of using the variable current limiter 31, the voltage adjustment unit 27 may calculate the field duty ratio at which the maximum excitation current I _max is obtained.

Note that the variable current limiter 31 discards the maximum excitation current I _max received from the control ECU 12, for example, and ends the limitation of the excitation current when a predetermined time elapses. As will be described later, the control ECU 12 continuously transmits the maximum excitation current I _max while receiving the high temperature abnormality signal. Therefore, while the high temperature abnormality is detected, the variable current limiter 31 operates as the excitation current. Can be limited to the maximum excitation current I _max or less. On the other hand, if the high temperature abnormality is not detected, the variable current limiter 31 can finish limiting the excitation current to the maximum excitation current I _max or less.

[Control ECU 12]
FIG. 3 shows an example of a functional block diagram of the control ECU 12. The control ECU 12 includes the communication unit 14, the FD _m / Im request unit 41, the maximum excitation current calculation unit 42, and the FD _g determination unit 43. These functions are realized by the CPU of the control ECU 12 executing a program stored in the EEPROM or by a circuit such as hardware such as an ASIC.

  When the communication unit 14 receives the high temperature abnormality signal from the IC regulator 13, for example, a communication interrupt is generated in the control ECU 12, and the program stored in the EEPROM is executed by the CPU.

First, when the communication unit 14 receives the high temperature abnormality signal, the FD _m / Im request unit 41 requests the IC regulator 13 to transmit the measured FD _m and the measured excitation current Im. Since the IC regulator 13 transmits the actually measured FD _m and the actually measured exciting current Im via the communication unit 32, the communication unit 14 of the control ECU 12 receives them. The communication unit 14 sends the actually measured FD _m and the actually measured exciting current Im to the maximum exciting current calculating unit 42. The FD _m / Im request unit 41 continuously requests the IC regulator 13 to transmit the measured FD _m and the measured excitation current Im for a predetermined time (for example, about 5 seconds). This is because the actually measured FD _m and the actually measured excitation current Im may fluctuate with respect to time. The maximum excitation current calculation unit 42 calculates, for example, an average of the actually measured FD _m and the actually measured excitation current Im during the predetermined time, thereby reducing the influence of fluctuations of both on the maximum excitation current I _max .

Further, the FD _g determining unit 43 determines the set capacity value FD _g based on a factor for estimating a preferable power generation amount. According to equation (A), the measured excitation current Im is reduced by the set capacity value FD _g. Therefore, if the other conditions such as the engine speed are constant, the higher the set capacity value FD _g is, the more power is generated. The amount becomes higher. First, setting capability value FD _g if a certain degree higher SOC of the battery 28 may be small. Conversely, when the SOC of the battery 28 is low, setting capability value FD _g better is large becomes preferably. Also, if the power consumption of the vehicle electrical loads even high SOC of the battery 28 is large, setting capability value FD _g better is large becomes preferably. Also, if the power consumption of the vehicle electric load even at low SOC of the battery 28 is small, resulting in setting ability value FD _g may be small. Further, since when the engine speed is low, the power generation efficiency decreases, it is preferably larger set capacity value FD _g, it would be smaller setting capability value FD _g when the engine speed is high. Further, when the temperature of the battery 28 is low, it is preferable acceptability is large set capacity value FD _g since lowering of the charging power when the temperature of the battery 28 is high, setting capability value since improved acceptance of the charging power The FD _g may be small. The FD _g determining unit 43 detects such various factors and determines the set capability value FD _g .

Specifically, the setting capacity value FD _g, for example, SOC of the battery 28, the power consumption of the vehicle electrical loads, the temperature of the engine speed and the battery 28, values such as 0 to 100% by using the map A Replace with ~ E respectively. Then, the set capability value FD _g is calculated by adding the weights normalized to each other. Note that α + β + γ + σ = 1.

Setting ability value FD _g = α · A + β · B + γ · C + σ · D
Further, in order to suppress the temperature rise of the alternator 11, setting capability value FD _g is required to be smaller than the field duty ratio to a high temperature abnormality is detected. Therefore, setting ability value FD _g calculated is 100 or less at maximum. Further, since the temperature rise cannot be suppressed when the set capability value FD _g becomes such a high value, the FD _g determination unit 43 determines the set capability value FD _g so as to be equal to or less than a predetermined upper limit. May be. In this case, the numerical A~E for example, as 0% to 70%, by setting the maximum value for the number to be replaced with lower, it is possible to suppress the upper limit of the setting ability value FD _g.

Then, the maximum excitation current calculation unit 42 calculates the maximum excitation current I _max from the equation (A). As described above, the maximum excitation current calculation unit 42 calculates the average of each of the plurality of actually measured FD _m and the actually measured excitation current Im received in a predetermined time. Since the set capability value FD _g <measured FD _m , the maximum exciting current I _max smaller than the actually measured exciting current Im can be calculated. For example, when the measured excitation current Im = 3.5 A, measured FD _m = 89%, and set capacity value FD _g = 50%, the maximum excitation current I _max is as follows.
Maximum excitation current _{I max = 3.5A × 50% /} 89% = 1.97A
The maximum excitation current calculation unit 42 transmits the maximum excitation current I _max to the IC regulator 13 via the communication unit 14. The maximum excitation current calculation unit 42 sets a number indicating that the maximum excitation current I _max is included in the data ID of the LIN communication. By doing so, the IC regulator 13 can suppress the maximum value of the excitation current and can suppress the temperature rise of the alternator 11.

[Operation procedure]
FIG. 4 shows an example of a flowchart showing a procedure when the control ECU 12 receives a high temperature abnormality signal. The flowchart of FIG. 4 starts when the ignition is turned on, for example.

  The control ECU 12 determines whether a high temperature abnormality signal has been received (S10). When the high temperature abnormality signal is not received (No in S10), the high temperature abnormality has not occurred in the alternator 11, so the control ECU 12 waits until it is received.

  When a high temperature abnormality signal is received (Yes in S10), an interruption occurs in the control ECU 12, and first, the control ECU 12 stores a diagnostic code in the EEPROM in order to record the high temperature abnormality of the alternator 11 (S20). The diag code is, for example, a symbol string combining alphabets and numerical values, and it becomes possible for a serviceman or the like to analyze what abnormality has occurred when viewing the diag code.

When the high temperature abnormality signal is received, the FD _m · Im request unit 41 requests the IC regulator 13 for the actual excitation current Im and the actual FD _m (S30). As a result, the control ECU 12 can receive a plurality of measured excitation currents Im and measured FD _m during a predetermined time. For example, the communication speed of LIN the measured FD _m and 100 about the measured excitation current Im to 5 seconds, can receive control ECU 12. The FD _m / Im requesting unit 41 does not request the actual excitation current Im and the actual FD _m from the IC regulator 13, but the IC regulator 13 sends the actual excitation current Im and the actual FD _m to the control ECU 12 together with the high temperature abnormality signal. You may send it.

Further, the FD _g determination unit 43 determines the set capability value FD _g while receiving the actual measured excitation current Im and the actual measured FD _m , for example (S40). Since the factor for determining the amount of power generation does not vary greatly within a predetermined time, the FD _g determination unit 43 may determine one set capacity value FD _g .

Then, the maximum excitation current calculation unit 42 calculates the maximum excitation current I _max (S50). Then, the maximum excitation current calculation unit 42 transmits the maximum excitation current I _max to the IC regulator 13 (S60). The IC regulator 13 detects that the maximum excitation current I _max is received from the data ID, and sets the maximum excitation current I _max in the variable current limiter 31. Therefore, the variable current limiter 31 sets the received maximum excitation current I _max to Suppress the excitation current so that it does not exceed. Therefore, the temperature rise of the alternator 11 can be suppressed.

It is a predetermined time (for example, 5 seconds) + α until the control ECU 12 transmits the maximum excitation current I _max to the IC regulator 13 after the IC regulator 13 starts transmitting the high temperature abnormality signal to the control ECU 12. During this time, the IC regulator 13 continuously transmits a high temperature abnormality signal to the control ECU 12.

After transmitting the maximum excitation current I _max to the IC regulator 13, the control ECU 12 determines whether or not a high temperature abnormality signal has been received (S70). When the high temperature abnormality signal is received (Yes in S70), the temperature of the alternator 11 remains the threshold T1 abnormality, so the process returns to step S60 and the transmission of the maximum excitation current I _max is repeated. Note that the determination in step S70 may be performed after several tens of seconds (for example, after 20 seconds) when a decrease in the temperature of the alternator 11 is expected. By doing so, the communication load between the IC regulator 13 and the control ECU 12 can be reduced.

When the high temperature abnormality signal is not received (No in S70), the temperature of the alternator 11 has dropped below the threshold value T1, so the processing of FIG. 4 ends.
FIG. 5 shows an example of a time chart when a high temperature abnormality is detected by the alternator 11. FIG. 5 also shows conventional high-temperature abnormality detection for comparison. Conventionally, control for suppressing the temperature rise is not performed until the temperature of the alternator 11 rises and becomes equal to or higher than the threshold value T2 at time t3. When the temperature of the alternator 11 becomes equal to or higher than the threshold T2, the overheat prevention unit 23 in FIG. 2 outputs a Low signal to the AND circuit 26, so that the alternator 11 stops power generation. As a result, the temperature of the alternator starts to decrease.

On the other hand, the control ECU 12 of this embodiment instructs the IC regulator 13 of the maximum excitation current I _max when the temperature of the alternator 11 rises and becomes equal to or greater than the threshold T1 at time t1. As a result, the alternator starts limiting the power generation amount. Even if the power generation amount is limited, the power generation amount does not become zero. By limiting the amount of power generation, the temperature of the alternator 11 gradually decreases or the temperature increase is suppressed from time t1. At time t2, when the temperature of the alternator 11 becomes lower than the threshold value T1, the alternator 11 returns the power generation amount to the original.

Thus, even if a high temperature abnormality of the alternator 11 is detected, the power generation is not stopped, so that the power generation amount determined by the maximum excitation current I _max can be secured at least. Therefore, the temperature rise of the alternator 11 can be suppressed while preventing the battery from running out due to insufficient power generation and the malfunction of the vehicle electrical load. Further, the process of limiting the excitation current to the maximum excitation current I _max or less is executed by the IC regulator 13 and the control ECU 12 only needs to calculate the maximum excitation current I _max , so the increase in the processing load of the control ECU 12 is also minimal. It can be suppressed to the limit.

In the present embodiment, the alternator is rotated by the rotation of the internal combustion engine (engine) to generate electric power. However, the alternator is not mounted on the electric vehicle, and the alternator is often not mounted on the hybrid vehicle. In the case of an electric vehicle or a hybrid vehicle, power is generated by a motor generator, but the motor generator also tends to become hot when the amount of power generation is large. The limitation of the power generation amount of the present embodiment can also be applied to a motor generator. In this case, the current supplied to the motor generator may be limited to a current corresponding to the maximum excitation current I _max or less.

[Modification]
FIG. 6 shows a modification of the schematic configuration diagram of the power generation control system 100. Conventionally, a charge lamp 17 is connected to the IC regulator 13, and the IC regulator 13 turns off the charge lamp 17 during power generation to the battery 28, and turns off the charge lamp 17 while the engine is stopped and is not generating power. It was lit. Therefore, the driver is notified of the presence or absence of charging by turning on or off the charge lamp 17. Further, the IC regulator 13 can provide power generation rate information to an external ECU. A field duty ratio is often used for the power generation rate information.

In the present embodiment, in addition to the information regarding the power generation of the alternator 11, the power generation amount is limited by providing the external ECU with power generation amount restriction information indicating that the IC regulator 13 restricts the power generation amount. This can be notified to the driver. When the IC regulator 13 receives the maximum excitation current I _max and sets it in the variable current limiter 31, the IC regulator 13 transmits the power generation amount restriction information to the control ECU 12. Since the control ECU 12 is connected to the meter ECU 16 by a CAN or the like, for example, the control ECU 12 can transmit the power generation amount restriction information to the meter ECU 16. Further, since the control ECU 12 can receive the power generation rate information together with the power generation amount restriction information, the meter ECU 16 can notify the driver of the power generation rate that is limiting the power generation amount.

  When the meter ECU 16 receives the power generation amount restriction information, for example, “Currently limiting the power generation amount” “Because the power generation amount is limited, please cooperate in reducing the power consumption” “The alternator is hot, A message such as “Currently limiting power generation” is displayed on the LCD panel of the meter panel.

  The meter ECU 16 may display this message with the charge lamp 17 turned on, or may display the message even when the charge lamp 17 is not turned on. For example, if the driver wants to notify the driver that power is being generated but the amount of power generation is limited, the meter ECU 16 displays a message with the charge lamp 17 lit. As a result, the driver can grasp that the amount of power generation is limited even when the charge lamp 17 is lit, and can easily prevent a sudden battery run-up and a shortage of electric power in the vehicle electrical load.

  Further, for example, if it is not desired to notify the driver that the power generation is limited because the power generation amount is limited, the meter ECU 16 displays a message in a state where the charge lamp 17 is not lit. Thereby, the driver can grasp that the amount of power generation is limited, and can further easily prevent a sudden battery run-up and a power shortage of the vehicle electrical load.

It is an example of the schematic block diagram of a power generation control system. It is an example of the figure which shows an example of a structure of an IC regulator typically. It is an example of the functional block diagram of ECU for control. It is an example of the flowchart figure which shows the procedure at the time of ECU for control receiving a high temperature abnormality signal. It is an example of a time chart figure at the time of detecting high temperature abnormality with an alternator. It is a modification of the schematic block diagram of a power generation control system.

11 Alternator 12 Control ECU
13 IC regulator 14, 32 Communication unit 15 Communication line 16 Meter ECU
25 switching element 28 battery 30 rotor coil 100 power generation control system

Claims (7)

In an electronic control unit connected by a communication line with an alternator that controls the power generation amount by an excitation current supplied by turning on or off the switching element with a PWM signal,
When the alternator is at a high temperature equal to or higher than a predetermined value, receiving means for receiving current value information including a current value of an excitation current and duty ratio information including a duty ratio of the PWM signal;
A calculation means for calculating a current value for limiting the excitation current by obtaining a ratio of the duty ratio to the capacity setting value that is smaller than the duty ratio and multiplying the current value by the ratio;
Transmitting means for transmitting to the alternator, the limiting current value information including the limiting current value, and request information requesting to limit the exciting current to be equal to or less than the limiting current value;
An electronic control unit comprising: Capability setting value determining means for calculating the capability setting value from a vehicle situation;
The electronic control unit according to claim 1, comprising: The capability setting value determining means includes
The electronic control unit according to claim 2, wherein the set capacity value is calculated by weighting at least one of a battery voltage, a power usage amount of a vehicle electrical load, an engine speed, or a battery temperature. The capability setting value determining means includes
Calculating the capacity setting value to be less than the duty ratio information;
The electronic control unit according to claim 2 or 3, wherein When the current value is Im, the duty ratio is FD _m , the capacity setting value is FD _g , and the limiting current value is I _max ,
The calculating means includes
I _max = Im × FD _g / FD _m
Calculating the limiting current value from
The electronic control unit according to claim 1, wherein: The alternator has a notification means for notifying a vehicle occupant that the excitation current has been limited to the current value for restriction or less.
The electronic control unit according to any one of claims 1 to 5, wherein In the excitation current control method of the alternator for controlling the power generation amount by the excitation current supplied by turning on or off the switching element with the PWM signal,
A receiving means, when the alternator is at a high temperature equal to or higher than a predetermined value, receiving current value information including a current value of an excitation current and duty ratio information including a duty ratio of the PWM signal;
Calculating a current value for limiting the excitation current by multiplying the current value by a ratio of the duty ratio to a capacity setting value that is smaller than the duty ratio;
A transmitting means for transmitting limiting current value information including the limiting current value and request information for requesting to limit an exciting current to be equal to or lower than the limiting current value, to the alternator;
An exciting current control method comprising: