JP3262572B2 - Alternator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alternator control device for controlling a terminal voltage of a battery to a target voltage by an alternator, and more particularly to a protective measure against alternator overvoltage.

[0002]

2. Description of the Related Art Conventionally, as this type of alternator control device, for example, as disclosed in Japanese Patent Application Laid-Open No. 55-157942, a vehicle-mounted battery charged by an alternator is provided, and the voltage of the vehicle-mounted battery is set. If the value is less than the value, a field current flows through the field coil of the alternator by the on operation of the control transistor, and a power generation flow flows through the armature coil to charge the vehicle-mounted battery, and when the battery voltage reaches the set value. And the control transistor is turned off.
By controlling the power flow, the battery voltage is feedback-controlled to a set value, and the field current is cut off when the output voltage of the alternator rises above a predetermined abnormally high voltage value. There is known a device in which the on-vehicle electrical components are protected from overvoltage by forcibly stopping the power generation.

[0003]

However, the above conventional overvoltage protection has the following disadvantages. That is, for example, at the time of starting the alternator, the output voltage of the alternator rises, exceeds the set value (overvoltage protection level), and becomes abnormally high, as shown in FIG. When this happens, the field current to the field coil is cut off, and when the output voltage drops below the overvoltage protection level, a large value of field current flows through the field coil, thereby causing the output voltage to reappear. Repeatedly becomes abnormally high pressure. As a result, the alternator repeats power generation and stop according to the intermittent flow of the field current, and at the time of power generation, the battery is charged and the battery voltage rises as shown in the figure, but the overvoltage protection is repeatedly activated and normal control is performed. As described above, the intermittent power generation flow of the alternator intermittently flows according to the flow of the field current, and the terminal voltage of the battery becomes unstable. there were.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an overvoltage protection for an alternator by continuously controlling a field current of the alternator so that a battery voltage at the time of starting or the like is suddenly reduced. The point is that the battery voltage is converged stably and quickly to the target voltage in a short time even when the voltage drops.

[0005]

In order to achieve the above object, the invention according to claim 1 is configured to control the output voltage in addition to the power generation current of the alternator. Sometimes, the configuration is such that the field current to the field coil is continuously reduced.

Specifically, as shown in FIG. 1, a specific solution of the present invention is an alternator 1, a battery 3 charged by the alternator 1, and a battery for detecting the voltage of the battery 3. Voltage detecting means 13 and the battery 3 detected by the battery voltage detecting means 13
The alternator 3 according to the deviation between the voltage of the
A first control means 25 for performing feedback control of a field current flowing through the field coil with a predetermined control gain, an output voltage detection means 14 for detecting an output voltage of the alternator 1, and an output voltage detection means 17 the output voltage of the alternator 1 that has been detected by the above alternator 1
When the voltage is equal to or higher than the overvoltage protection voltage, the alternator 1
A second control means for feedback-controlling the output voltage to the overvoltage protection voltage with a control gain set to be larger than the control gain of the first control means 25 is provided.

According to a second aspect of the present invention, in place of the second control means of the first aspect of the present invention, the output voltage detected by the output voltage detecting means is changed to the alternator. When the voltage is equal to or higher than the overvoltage protection voltage of 1, the feedback control of the field current by the control means 25 is prohibited, and a protection means for reducing the field current is provided.

[0008]

According to the above-mentioned structure, according to the first aspect of the present invention,
The field current of the alternator 1 is feedback-controlled by the first control means 25 to adjust the value of the power generation current, and the output voltage of the alternator is feedback-controlled by the second control means 26.

In such a case, for example, at the time of starting when the starter operates,
In situations where the voltage of the battery 3 is decreased abruptly, since feedback control of the output voltage by the second control means 26 having a large control gain is dominant, while the output voltage of the alternator 1 is restricted to the overvoltage protection voltage, the overvoltage protection
The battery 3 is charged with the maximum power flow corresponding to the voltage . As a result, even if the voltage of the battery 3 is low, it is quickly charged in a short time. In addition, since the field current of the alternator 1 changes continuously by the feedback control of the output voltage to the overvoltage protection voltage by the second control means 26, the power generation current also changes continuously, and the voltage of the battery 3 becomes smooth. It rises while being stable.

The battery voltage rises by the feedback control of the output voltage of the second control means 26,
If the voltage deviation becomes a small value and the generated voltage of the alternator 1 drops and becomes less than the overvoltage protection voltage , the feedback control of the output voltage becomes unnecessary, and the feedback control by the first control means 25 having a small control gain at this point. Appears, and the battery voltage is accurately feedback-controlled to the target value.

According to the second aspect of the present invention, if the output voltage of the alternator 1 becomes abnormally high or higher than the overvoltage protection voltage at the time of starting or the like, the field current of the alternator 1 is controlled to be reduced by the protection means. The output voltage of the alternator 1 decreases while the flow of the field current continues. Therefore, since the generated current of the alternator 1 continues to flow to the battery 3 due to the continuation of the flow of the field current, the battery voltage is stabilized without becoming unstable.

[0012]

As described above, according to the alternator control device of the first and second aspects of the present invention, even when the difference between the battery voltage and the target voltage is large, such as at the time of starting. Thus, the battery voltage can be quickly and stably converged to the target voltage in a short time without making the output voltage of the alternator overvoltage.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 is a diagram showing the overall configuration when applied to a vehicle alternator control device. In the figure, reference numeral 1 denotes an alternator which is composed of a separately-excited AC generator and is driven and linked to the output shaft of the engine, and includes therein a three-phase armature coil 1a and nine rectifying diodes D1 to D9. And a field coil 1b.

Reference numeral 2 denotes a controller for controlling the flow of power generated by the alternator 1. Reference numeral 3 denotes a vehicle-mounted battery which is charged from the alternator 1 via a power supply harness 4. Reference numeral 5 denotes a vehicle ignition key connected to the vehicle-mounted battery 3. In-vehicle electrical components such as a power window and a rear heating wire connected via the power line.

The controller 2 includes a control transistor Tr1 for duty-controlling the energization of the field coil 1b of the alternator 1, and a control unit 10 having a CPU therein. /
The rectifier diode D7 of the alternator 1 is connected to the D terminal 10a.
To D9, the terminal voltage Vs of the battery 3 is applied to the other A / D terminal 10b, and the terminal voltage Vs of the battery 3 is input to the A / D terminal 10b. The input terminal 10a constitutes the output voltage detection means 14 for detecting the output voltage Vt of the alternator 1 while the battery voltage detection means 13 detects the output voltage Vt. Another A / D terminal 1
An intake air temperature signal of an intake air temperature sensor 11 for detecting an intake air temperature around the vehicle is input to 0c, and a base of the control transistor Tr1 is connected to a PWM terminal 10d.
The base of a transistor Tr2 for controlling lighting of the power generation warning lamp 12 is connected to the terminal 10e.

Next, the power generation control of the alternator 1 by the controller 2 will be described with reference to the block diagram of FIG. In the figure, 15 estimates the temperature of the electrolyte of the vehicle-mounted battery 3 based on the intake air temperature signal of the intake air temperature sensor 11, and based on the temperature, the target voltage Vre of the vehicle-mounted battery 3
Target voltage setting means 16 for correcting and setting g is a subtractor for subtracting the terminal voltage Vs of the vehicle-mounted battery 3 from the target voltage Vreg of the target voltage setting means 15. Reference numeral 17 denotes target generator current setting means for setting the target generator current of the alternator 1 by proportional-integral control.
The voltage deviation ΔV (= Vreg−Vs) obtained in the above is input, and the target power generation flow ia is calculated based on the voltage deviation ΔV, the proportionality constant Kp, and the integration constant Ki from the following equation ia = Kp · ΔV + ∫Ki · ΔVdt. It is to be calculated and set.

Further, reference numeral 18 denotes a target power generation flow ia set by the target power generation flow setting means 17 and an engine rotation speed Ne signal as a drive rotation speed of the alternator 1, and the engine rotation speed Ne is obtained from a map stored in advance. Ne, a target field current calculating means for calculating a target field current ift according to the target power generation flow ia; 19 a field coil for the target field current ift calculated by the target field current calculating means 18 Control field current calculation means for performing first-order correction for compensating for a delay in change of the field current caused by the inductance of the control field current 1b to calculate the control field current ifc. Control field current ifc
, And obtains the control duty ratio fduty signal by the control transistor tr.
1 is a control duty ratio calculation means for outputting to a base. In the figure, reference numeral 21 denotes an idle speed electrical load correction means for correcting the idle speed of the engine during the operation of the on-vehicle electrical component 5 based on the target power flow ia set by the target power flow setting means 17. .

Next, the control of the power flow and the output voltage of the alternator 1 by the controller 2 will be described with reference to the control flow of FIG. After starting, in step S1, various state signals such as the intake air temperature, the battery voltage Vt, the alternator internal output voltage Vt, and the engine speed Ne are input, and then in step S2, the alternator internal output voltage Vt is input.
t is subtracted from the overvoltage protection voltage Vo, and the subtraction result (V
Based on t-Vo), a control gain for overvoltage protection is read from the overvoltage protection table shown in FIG. 5, and in step S4, the power generation flow ia of the alternator 1 is feedback-corrected by the control gain.

Thereafter, a deviation ΔV (Vs−Vreg) between the target voltage Vreg of the vehicle-mounted battery 3 and the battery voltage Vs corresponding to the read intake air temperature is calculated in step S5, and the deviation ΔV is calculated in step S6. Then, a control gain for power generation control is read from the target power generation control gain table shown in FIG. Here, in the table of FIG. 5, in the region where the voltage deviation (Vt−Vo) is a positive value, the absolute value of the control gain for overvoltage protection is the absolute value of the control gain for power generation current control that is read out at the same time. The characteristic is always set to a value larger than the value. Then, in step S7, the power generation flow ia corrected for overvoltage protection is further subjected to feedback correction with the control gain for power generation current control.

Thereafter, in step S8, the control duty ratio fduty of the control transistor Tr1 corresponding to the corrected power generation flow ia is calculated, and in step S9, the duty ratio of the transistor Tr1 is controlled by the control duty ratio fduty signal. And return.

Therefore, in the control flow of FIG.
In steps S5 to S9, the terminal voltage Vs of the vehicle-mounted battery 3 and the target voltage Vre detected from the input terminal 10b.
The target power generation current gain is read from FIG. 5 in accordance with the deviation ΔV from g, the target power generation current ia of the alternator 1 is corrected based on the control gain, and a control duty ratio fduty signal corresponding to the correction value ia is used. The first control means 25 is configured to perform a duty control of the control transistor Tr1 to feedback-control a field current flowing through the field coil 1b with a predetermined control gain. Steps S2 to S4, S8 and S9 of the control flow
Accordingly, the overvoltage protection gain is read from FIG. 5 according to the deviation between the internal output voltage Vt of the alternator 1 input from the input terminal 10a and the overvoltage protection value Vo, and the target power generation flow ia of the alternator 1 is determined based on the control gain. By controlling the duty ratio of the control transistor Tr1 with the control duty ratio fduty signal corresponding to the correction value ia, the output voltage Vt of the alternator 1 is set higher than the control gain of the first control means 25. N
In constituting the second control means 26 so as to feedback control the overvoltage protection voltage Vo.

Therefore, in this embodiment, the terminal voltage Vs of the on-vehicle battery 3 drops sharply with the operation of the starter, such as when the engine is started, and the deviation ΔV (Vs−Vreg) between the battery voltage Vs and its target voltage Vreg. ) (Negative value)
Becomes large, the large target power generation current gain (positive value) is read from FIG. 5 and the target power generation current ia rapidly increases.
The internal output voltage Vt of the alternator 1 is equal to the overvoltage protection voltage Vt.
Above o, an abnormal voltage may occur.

However, when the abnormal voltage occurs, the overvoltage protection gain (negative value) is always set to the target power generation gain (positive value).
, The control gain value obtained by combining the two becomes a negative value, and the overvoltage protection control based on the overvoltage protection gain becomes dominant. As a result, the internal output voltage Vt of the alternator 1 decreases, and the above-mentioned overvoltage protection voltage Vo
Convergence control, and is protected well from abnormal high pressure.

In addition, since the power generation flow ia of the alternator 1 is continuously feedback-controlled by the overvoltage protection gain, the power generation flow always flows into the vehicle-mounted battery 3 and is constantly charged. V
s rises quickly in a short time while being stable.

FIG. 6 shows an embodiment of the second aspect of the present invention. The flow of power generation control will be described with reference to FIG.
After inputting various state signals such as the above, at step S2, the internal output voltage Vt of the alternator 1 is compared with a first overvoltage protection set value (overvoltage protection voltage) Vg1 shown in FIG. The value is compared with a second overvoltage protection voltage value Vg2 smaller than the set value Vg1. And Vt
If ≧ Vg1, the feedback prohibition flag Xnefb is set to Xnefb = 1 in step S4, and Vt <V
In the case of g2, the prohibition flag Xnef is determined in step S5.
Reset to b = 0.

In step S6, the prohibition flag X
The value of nefb is determined, and when feedback control of Xnefb = 0 is possible, the target power generation flow ia is determined in step S7.
Is the voltage deviation (Vs-Vre) shown in FIG.
The feedback control is performed with the target power generation current gain according to g), and the control duty ratio fduty of the control transistor Tr1 corresponding to the feedback corrected target power generation current ia is calculated in step S8. On the other hand, when Xnefb = 1 is prohibited, the alternator 1
It is determined that an overvoltage has occurred, and a predetermined reduction value KPRT is subtracted from the target power generation flow ia in step S9, and a control duty ratio fduty corresponding to the target power generation flow ia resulting from the subtraction is calculated in step S8. I do. After that, the control transistor Tr1 is duty-controlled by the calculated control duty ratio fduty, and the process returns.

Therefore, in the control flow of FIG.
In steps S7 , S8 and S10, the onboard battery 3
ΔV (Vs−V) between the voltage Vs and the target voltage Vreg.
(reg), and constitutes a control means 27 for performing feedback control of the field current flowing through the field coil 1b of the alternator 1. After the alternator internal output voltage Vt detected at the input terminal 10a of the control unit 10 becomes equal to or higher than the first overvoltage protection set value Vg1 in steps S2 to S6 and S9, the field current by the control means 27 is changed. The protection means 28 is configured to prohibit the feedback control described above and reduce the field current by a predetermined value KPRT.

Therefore, in the present embodiment, as shown in FIG. 7, feedback control of the target power generation flow ia is initially performed, and thereafter, the internal output voltage Vt of the alternator 1 becomes equal to or higher than the first overvoltage protection set value Vg1. Rises to
From this time, the target power generation flow ia is set to the set value K until the internal output voltage Vt falls below the second overvoltage protection set value Vg2.
The feedback control of the target power generation flow ia is restarted at the time when the PRT is decreased by PRT, and eventually falls below the second set value Vg2, so that an abnormally high voltage of the internal output voltage Vt of the alternator 1 is prevented as much as possible. However, the battery voltage Vs can be favorably converged to the target voltage Vreg with a small control gain.

In this case, after the internal output voltage Vt of the alternator 1 becomes an abnormally high voltage equal to or higher than the first overvoltage protection set value Vg1 , the generator current of the alternator 1 is changed to the set value KPRT.
When the on-board battery 3 continues to be charged and its terminal voltage Vs stably rises, the power generation flow is cut off immediately. , The time required to converge to the target voltage Vreg can be effectively reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the invention described in claim 1;

FIG. 2 is an electric circuit diagram showing the entire configuration of the alternator control device.

FIG. 3 is a block diagram showing power generation flow control of the alternator.

FIG. 4 is a flowchart showing the power generation flow control.

FIG. 5 is a diagram illustrating an overvoltage protection gain and a target power generation current gain map.

FIG. 6 is a flow chart showing power generation flow control according to the second aspect of the present invention.

FIG. 7 is an explanatory diagram of the operation.

FIG. 8 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Alternator 1b Field coil 2 Controller 3 In-vehicle battery 10a, 10b Input terminal 13 Battery voltage detection means 14 Output voltage detection means Tr1 Control transistor 25 First control means 26 Second control means 27 Control means 28 Protection means

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-212200 (JP, A) JP-A-62-104440 (JP, A) JP-A-62-217828 (JP, A) JP-A 63-104 206127 (JP, A) JP 1-56617 (JP, B2) (58) Fields surveyed (Int. Cl. ⁷ , DB name) H02J ^7/ 14-7/24 H02P 9/30

Claims (2)

(57) [Claims] An alternator; a battery charged by the alternator; a battery voltage detecting means for detecting a voltage of the battery; and a difference between a battery voltage detected by the battery voltage detecting means and a target voltage. A first control means for feedback-controlling a field current flowing through a field coil of the alternator with a predetermined control gain; an output voltage detection means for detecting an output voltage of the alternator; The output voltage of the alternator is higher than the overvoltage protection voltage of the alternator
When the overvoltage the output voltage of the alternator control gain set larger than the control gain of the first control means
An alternator control device comprising: a second control unit that performs feedback control on the protection voltage . 2. An alternator, a battery charged by the alternator, a battery voltage detecting means for detecting a voltage of the battery, and a difference between a battery voltage detected by the battery voltage detecting means and a target voltage. Te feedback control of the field current flowing through the field coil of the alternator control means and an output voltage detecting means for detecting an output voltage of the alternator, the detected output voltage is above O by the output voltage detection means
An alternator control device, comprising: protection means for inhibiting the feedback control of the field current by the control means when the voltage is equal to or higher than the overvoltage protection voltage of the alternator and reducing the field current.