JP4450085B2 - Vehicle power generation control device - Google Patents

Description

  The present invention relates to a vehicle power generation control device that controls a power generation state of a vehicle generator based on a power generation control instruction value from an external command device such as an engine control device in a vehicle equipped with an engine.

Some recent vehicle power generation control devices have a variable control function for the generated voltage and a sudden increase in power generation torque when an electric load is applied based on the power generation control instruction value from an external command device such as an engine control device. Some have a function that allows the field current to be gradually increased in order to reduce it.In addition, in order to prevent the battery from being insufficiently charged due to the power generation control command value from the external command device, below the minimum battery charge voltage, There is a combination of functions for prohibiting power generation control instructions from an external command device (see, for example, Patent Document 1).
JP 2006-115619 A (page 4-10, FIG. 1-10)

  By the way, in the conventional method of Patent Document 1 described above, when a relatively large electrical load or an electrical load with a large inrush current is applied, depending on the vehicle state, the external power generation control prohibition voltage may be temporarily reduced or lower. In this case, the power generation torque suddenly increases due to rapid power generation, the engine speed becomes unstable, and in the worst case, the engine may stall.

  The present invention was created in view of such points, and its purpose is to maintain appropriate power generation control even when the power generation voltage becomes equal to or lower than the external control prohibition voltage due to the input of an electric load or the like. An object of the present invention is to provide a vehicular power generation control device capable of preventing the occurrence of engine stall.

  In order to solve the above-described problem, a vehicle power generation control device according to the present invention is configured to generate a field current to be supplied to a field winding of a vehicle generator based on a power generation control instruction signal output from an external command device. Field power control means to control and vehicle power generation so that when the power generation voltage of the vehicle generator falls below the external control prohibition voltage in accordance with the power generation control instruction signal, it preferentially exceeds the external control prohibition voltage Power generation priority control means for performing power generation control of the power generator, and power generation priority control prohibition means for prohibiting the operation of the power generation priority control means for a predetermined time when the power generation voltage of the vehicle generator temporarily falls below the external control prohibition voltage. The predetermined time during which the operation of the power generation priority control means is temporarily prohibited by the power generation priority control prohibiting means is controlled by a field current gradual increase control that reduces the sudden increase in power generation torque when an electric load is applied by an external command device. time It is set to above. Even when the power generation voltage of the vehicular generator is equal to or lower than the external control prohibition voltage, the operation of performing the power generation control of the vehicular generator is temporarily prohibited so that it is preferentially higher than the external control prohibition voltage. Therefore, it is possible to prevent the power generation torque from rapidly increasing, and it is possible to prevent the engine speed from becoming unstable and causing engine stall. Further, by prohibiting the power generation control for increasing the power generation voltage only for a predetermined time, it is possible to maintain the appropriate power generation control without the power generation voltage being extremely reduced.

  Further, the power generation control instruction signal described above is a PWM signal, and it is desirable that the power generation priority control prohibiting unit variably sets a predetermined time for temporarily prohibiting the operation of the power generation priority control unit according to the period of the PWM signal. . As a result, it is possible to set an appropriate power generation control prohibition time in consideration of engine speed fluctuation and the like in the external command device.

  In addition, the predetermined time during which the operation of the power generation priority control means is temporarily prohibited by the power generation priority control prohibiting means described above is the control of the gradual increase control of the field current that reduces the sudden increase of the power generation torque when the electric load is applied by the external command device. It is desirable to set within a range of 1 to 2 times the time. Thereby, the influence on the insufficient charging of the battery can be minimized.

  Further, it is desirable to set the predetermined time during which the operation of the power generation priority control means is temporarily prohibited by the power generation priority control prohibition means described above to approximately 10 seconds. This eliminates the need to set a prohibition time for each vehicle, simplifies the process and allows common use of software to be used, thereby reducing costs.

  Hereinafter, a power generation system according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating an overall configuration of a power generation system according to an embodiment. As shown in FIG. 1, the power generation system of the present embodiment includes a vehicle generator 2 that includes a vehicle power generation control device 1, an ECU (engine control device) 5 as an external command device, and a battery 3. ing. An electric load 4 is connected to the battery 3 in parallel. The vehicular generator 2 is driven by an engine (not shown).

  The vehicle generator 2 includes a field winding 23 provided in a rotor, a three-phase armature winding 21 included in the stator, and a rectification that full-wave rectifies the three-phase output of the armature winding 21. At least one pair of circuits 22 and a vehicle power generation control device 1 that controls the excitation current of the vehicle generator 2 are provided. The output terminal (B terminal) of the vehicular generator 2 is connected to the battery 3 and the electric load 4, and power is supplied to the battery 3 and the like from this output terminal. The output current of the vehicular generator 2 is adjusted by controlling the excitation current supplied to the field winding 23.

  The vehicle power generation control device 1 includes a field current limiting unit and a switching element 11, a freewheeling diode 12 as a field current circulating unit, and a control circuit 10. An exciting circuit for supplying magnetic flux to the field winding 23 of the rotor of the vehicle generator 2 is constituted by the switching element 11 and the freewheeling diode 12. The switching element 11 is connected in series with the field winding 23, is PWM (pulse width modulation) controlled by the control circuit 10, and supplies an excitation current to the field winding 23. The freewheeling diode 12 is connected in parallel to the field winding 23 and recirculates the exciting current flowing through the field winding 23 when the switching element 11 is turned off.

  The ECU 5 is connected to the control circuit 10 in the vehicular power generation control device 1 via a communication terminal (C terminal) of the vehicular generator 2, and the PWM signal output circuit 51 and the mode determination / instruction value determination circuit. 52. The ECU 5 realizes necessary functions by executing predetermined software (control program) stored in a ROM or RAM by a processor. The mode determination / instruction value determination circuit 52 selects a control mode based on vehicle information such as the vehicle speed, the engine speed, the connection state of the electric load 4, the voltage of the battery 3 or the power generation voltage of the vehicle generator 2, and the accelerator opening. And a command value for the vehicle power generation control device 1 is determined, and a field current gradually increasing control function (gradually increasing the field current gradually) that reduces a sudden increase in power generation torque when the amount of power generation is increased due to the input of an electric load or the like. (Excitation control function or load response control function). The PWM signal output circuit 51 outputs a PWM signal as a power generation control instruction signal having an instruction value corresponding to the determined control mode to the vehicle power generation control device 1.

  FIG. 2 shows the duty ratio (horizontal axis) of the PWM signal output from the ECU 5 toward the vehicle power generation control device 1 and the conductivity (vertical axis) of the field winding 23 (or the switching element 11) of the vehicle generator 2. FIG. The duty of the PWM signal corresponds to 0% of the conductivity of the field winding 23 or the switching element 11, and the duty of 100% of the PWM signal corresponds to the conductivity of the field winding 23 or the switching element 11 of 100%. . The ECU 5 outputs this PWM signal whose duty gradually increases at the timing of turning on the electric load or the like. The control circuit 10 in the vehicular power generation control device 1 performs on / off control of the switching element 11 so as to have a conductivity corresponding to the PWM signal input from the ECU 5.

  FIG. 3 is a diagram illustrating a detailed configuration of the control circuit 10. As shown in FIG. 3, the control circuit 10 of this embodiment includes a drive circuit 13, an OR circuit 14, a field current control circuit 15, a power generation priority control circuit 16, and a power generation priority control prohibition circuit 17. . The field current control circuit 15 corresponds to the field current control means, the power generation priority control circuit 16 corresponds to the power generation priority control means, and the power generation priority control prohibition circuit 17 corresponds to the power generation priority control prohibition means.

  The field current control circuit 15 includes a reference voltage generation circuit 151, a voltage comparator 152, and a control duty generation circuit 153. The reference voltage generation circuit 151 generates a reference voltage used for high / low level determination of a PWM signal (power generation control instruction signal) input from the ECU 5. This reference voltage is applied to the negative input terminal of the voltage comparator 152. The voltage comparator 152 performs voltage comparison between the reference voltage applied to the negative input terminal and the PWM signal input to the positive input terminal via the communication terminal, and the voltage of the PWM signal is higher than the reference voltage. In this case, a high level signal is output, and in the opposite case, a low level signal is output. The control duty generation circuit 153 outputs a control signal having the same duty as the output signal of the voltage comparator 152. This control signal is input to one input terminal of the OR circuit 14.

  The power generation priority control circuit 16 includes voltage dividing resistors 161 and 162, a reference voltage generation circuit 163, and a voltage comparator 164. The voltage dividing circuit configured by the voltage dividing resistors 161 and 162 divides the generated voltage appearing at the output terminal of the vehicular generator 2. This divided voltage is applied to the negative input terminal of the voltage comparator 164. The reference voltage generation circuit 163 generates a reference voltage corresponding to the external control inhibition voltage. This external control prohibition voltage is given priority when the power generation control of the vehicle generator 2 falls below this external control prohibition voltage as a result of performing power generation control in response to the power generation control instruction signal sent from the ECU 5. Thus, the voltage is a threshold value for performing the power generation control of the vehicular generator 2 so as to be equal to or higher than the external control inhibition voltage. The voltage comparator 164 outputs a high level signal when the voltage applied to the negative input terminal becomes equal to or lower than the reference voltage applied to the positive input terminal.

  The power generation priority control prohibition circuit 17 includes a control temporary prohibition circuit 171 and an analog switch 172. The analog switch 172 is inserted between the output terminal of the voltage comparator 164 in the power generation priority control circuit 16 and the other input terminal of the OR circuit 14, and inputs a signal from the voltage comparator 164 to the OR circuit 14. Block / allow. The control temporary prohibition circuit 171 turns off the analog switch 172 for a predetermined time after the output signal of the voltage comparator 164 changes from the low level to the high level, and then turns it on, so that the control temporary prohibition time corresponding to the predetermined time is reached. Set. This temporary control inhibition time is set to be equal to or longer than the gradual increase control time of the field current based on the external control signal (for example, within a range of 1 to 2 times).

  Even if control is performed in which the duty of the PWM signal output from the ECU 5 gradually increases in response to turning on of the electric load, etc., if the power generation voltage of the vehicle generator 2 does not fall below the external control inhibition voltage, power generation priority Since the output signal of the voltage comparator 164 in the control circuit 16 maintains the low level, the signal input to the other input terminal of the OR circuit 14 also maintains the low level. Therefore, the signal output from the field current control circuit 15 is input to the drive circuit 13 as it is. The drive circuit 13 performs on / off control of the switching element 11 with the duty of the signal output from the OR circuit 14. As a result, control for gradually increasing the field current flowing in the field winding 23 is performed.

  On the other hand, when a large electric load is applied, control is performed in which the duty of the PWM signal output from the ECU 5 is gradually increased. However, the power generation voltage of the vehicle generator 2 is equal to or lower than the external control prohibition voltage. Will happen. In this case, since the output signal of the voltage comparator 164 in the power generation priority control circuit 16 changes from low level to high level, it is input to the other input terminal of the OR circuit 14 after a predetermined time has elapsed from the timing of this change. Signal to be changed from low level to high level. Therefore, the signal output from the field current control circuit 15 is input to the drive circuit 13 as it is until the predetermined time elapses, but thereafter, the output signal of the OR circuit 14 changes to a high level. The drive circuit 13 turns on the switching element 11 according to the high level signal output from the OR circuit 14. As a result, the field current flowing in the field winding 23 is controlled to increase gradually until a predetermined time elapses, and is controlled to increase rapidly after the predetermined time elapses.

  FIG. 4 is a diagram illustrating the operation timing of the vehicle power generation control device 1 of the present embodiment when a large electrical load 4 is input during idling. FIG. 5 is a diagram showing the operation timing of the vehicular power generation control device of the conventional configuration when a small electric load is applied during idling. FIG. 6 is a diagram illustrating the operation timing of the vehicular power generation control device of the conventional configuration when a large electric load is applied during idling. FIG. 5 and FIG. 6 are for explaining the difference from the operation timing of the present embodiment shown in FIG. 4. As a conventional configuration, the power generation priority control prohibition included in the configuration of the present embodiment shown in FIG. 3 is prohibited. It is assumed that the circuit 17 is omitted and the output terminal of the voltage comparator 164 is directly connected to the other input terminal of the OR circuit 14.

  As shown in FIG. 5, when a small electric load is input in the conventional configuration, the ECU 5 detects the input of the electric load 4 (or the increase in the amount of power generated by the vehicle generator 2), and the vehicle generator 2 In order to reduce the sudden increase in power generation torque, field current gradually increasing control (control for gradually increasing the duty of the PWM signal) is performed. During this control, the power generation voltage of the battery 3 or the vehicle generator 2 temporarily decreases but does not fall below the external control inhibition voltage, so that the field current gradually increasing control is performed as it is. As a result, a sudden increase in power generation torque is suppressed, and fluctuations in engine speed are also suppressed.

  On the other hand, as shown in FIG. 6, when a large electrical load is applied in the conventional configuration, the drop in the generated voltage of the battery 3 or the vehicle generator 2 becomes large and falls below the external control inhibition voltage. The priority control circuit 16 is activated, the output of the voltage comparator 164 becomes high level, the output of the OR circuit 14 also becomes high level, and the generator 2 for the vehicle fully generates power. Engine speed fluctuation occurs.

  On the other hand, as shown in FIG. 4, when a large electric load is applied in the configuration of the present embodiment, the drop in the generated voltage of the battery 3 or the vehicle generator 2 becomes large and the external control prohibited voltage or less. However, even if the power generation priority control circuit 16 is operated, the high level output signal of the voltage comparator 164 is not input to the OR circuit 14 as it is, and this high level output signal is not generated by the power generation priority control prohibition circuit 17. Is temporarily interrupted. During this time, since the control based on the PWM signal input from the ECU 5 is continued, it is possible to suppress a sudden increase in power generation torque and to suppress fluctuations in the engine speed.

  Thus, in the vehicular power generation control device 1 of the present embodiment, even when the power generation voltage of the vehicular generator 2 becomes equal to or lower than the external control prohibition voltage, it preferentially exceeds the external control prohibition voltage. Since the operation for performing the power generation control of the vehicular generator 2 is temporarily prohibited, it is possible to prevent the power generation torque from rapidly increasing, and to prevent the engine speed from becoming unstable and causing engine stall. can do. Further, by prohibiting the power generation control for increasing the power generation voltage only for a predetermined time, it is possible to maintain the appropriate power generation control without the power generation voltage being extremely reduced.

  In addition, by setting the control temporary prohibition time in the range of 1 to 2 times the control time of the gradual increase control of the field current that reduces the sudden increase of the generated torque when the electric load is applied by the ECU 5, the influence on the insufficient charging of the battery 3 is achieved. Can be minimized.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. In the above-described embodiment, the case where the control temporary prohibition time for delaying the on-timing of the analog switch 172 by the control temporary prohibition circuit 171 is constant, but this time may be varied according to an instruction from the ECU 5. Good.

  FIG. 7 is a diagram showing a modification of the control circuit that varies the temporary control prohibition time in accordance with an instruction from the ECU 5. The control circuit 10A shown in FIG. 7 differs from the control circuit 10 shown in FIG. 3 in that the power generation priority control prohibition circuit 17 is replaced with a power generation priority control prohibition circuit 17A. In the power generation priority control prohibition circuit 17A, a cycle detection circuit 173 is added to the power generation priority control prohibition circuit 17. The period detection circuit 173 detects the period of the PWM signal input from the ECU 5 and varies the control temporary prohibition time set by the control temporary prohibition control circuit 171. In this manner, by appropriately setting the control temporary prohibition time in accordance with an instruction from the ECU 5, it is possible to set an appropriate power generation control prohibition time in consideration of engine speed fluctuations and the like in the ECU 5.

  In the above-described embodiment, the control temporary prohibition time is set to be equal to or longer than the gradually increasing control time of the field current based on the external control signal (for example, within a range of 1 to 2 times). You may make it fix to second. This eliminates the need to set a prohibition time for each vehicle, simplifies the process and allows common use of software to be used, thereby reducing costs.

It is a figure showing the whole power generation system composition of one embodiment. It is a figure which shows the relationship between the duty of the PWM signal output toward ECU for vehicle electric power generation control, and the continuity of the field winding of a vehicle generator. It is a figure which shows the detailed structure of a control circuit. It is a figure which shows the operation | movement timing of the vehicle electric power generation control apparatus of this embodiment when a big electric load is thrown in at the time of idling. It is a figure which shows the operation | movement timing of the vehicle electric power generation control apparatus of the conventional structure when a small electric load is thrown in at the time of idling. It is a figure which shows the operation | movement timing of the vehicle electric power generation control apparatus of the conventional structure when a big electric load is thrown in at the time of idling. It is a figure which shows the modification of the control circuit which varies the control temporary prohibition time according to the instruction | indication from ECU.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle power generation control apparatus 2 Vehicle generator 3 Battery 4 Electric load 5 ECU (engine control apparatus)
DESCRIPTION OF SYMBOLS 10 Control circuit 11 Switching element 12 Freewheeling diode 13 Drive circuit 14 OR circuit 15 Field current control circuit 16 Power generation priority control circuit 17 Power generation priority control prohibition circuit 21 Armature winding 22 Rectifier circuit 23 Field winding 51 PWM signal output circuit 52 Mode decision / indication value decision circuit

Claims (4)

Field current control means for controlling the field current supplied to the field winding of the vehicle generator based on the power generation control instruction signal output from the external command device;
When the power generation voltage of the vehicular generator becomes equal to or lower than the external control prohibition voltage according to the power generation control instruction signal, the power generation control of the vehicular generator is preferentially equal to or higher than the external control prohibition voltage. Power generation priority control means to perform;
Power generation priority control prohibiting means for prohibiting the operation of the power generation priority control means for a predetermined time when the power generation voltage of the vehicle generator temporarily falls below the external control prohibition voltage;
The predetermined time during which the operation of the power generation priority control means is temporarily prohibited by the power generation priority control prohibiting means is a gradual increase in field current that reduces a sudden increase in power generation torque when the electric load is applied by the external command device. A vehicle power generation control device characterized in that it is longer than the control time of control. In claim 1,
The power generation control instruction signal is a PWM signal,
The power generation priority control prohibiting unit variably sets the predetermined time for temporarily prohibiting the operation of the power generation priority control unit according to the period of the PWM signal. In claim 1 or 2,
The predetermined time during which the operation of the power generation priority control means is temporarily prohibited by the power generation priority control prohibiting means is a control of gradually increasing control of the field current that reduces the sudden increase in power generation torque when the electric load is applied by the external command device. A power generation control device for a vehicle, which is set within a range of 1 to 2 times the time. In claim 1,
The power generation control device for a vehicle, wherein the predetermined time during which the operation of the power generation priority control means is temporarily prohibited by the power generation priority control prohibition means is set to approximately 10 seconds.

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