JP2932474B2 - Voltage regulator for vehicle charging generator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage regulator for a vehicle charging generator, and more particularly to a voltage regulator operable to reduce an engine load during low-speed rotation. [Prior Art] A vehicle charging generator is connected to an engine and rotates, and a heavy load is imposed on the engine during power generation. The power generation of the charging generator is controlled by a voltage regulator, and the voltage regulator controls ON-OFF of the rotor coil current of the charging generator so that the battery charging voltage is always constant. By the way, when a relatively large electric load is applied when the engine is running at a low speed such as idling, the voltage regulator suddenly increases the duty ratio of the rotor coil current in order to keep the battery charging voltage constant. Engine stall. One solution to this problem is disclosed in, for example, JP-A-59-8360.
No. 0 publication discloses that when the battery charging voltage is reduced by a certain amount or more due to a large electric load input, this is detected, and the rate of increase of the rotor coil current thereafter is suppressed to a certain ratio, so that an excessive load is not applied to the engine. A voltage regulation device has been proposed. [Problems to be Solved by the Invention] However, in the above-described conventional apparatus, power generation of the charging generator is not suppressed at all until the battery charging voltage decreases by a certain amount. Can occur. For example, an increase in the electrical load within the power generation capacity of the charging generator does not cause a decrease in the battery charging voltage, so that the rotor coil current rapidly increases without being suppressed. SUMMARY OF THE INVENTION The present invention solves such a problem, and a voltage adjusting device of a vehicle charging generator capable of always preventing a sudden increase in a rotor coil current regardless of the level of a battery charging voltage and thereby preventing an engine stall from occurring. The purpose is to provide. [Means for Solving the Problems] The configuration of the present invention will be described with reference to the drawings.
The vehicle includes a switch means 11 for controlling ON / OFF of a current of a rotor coil 21 of the vehicle charging generator 2 to maintain a battery charging voltage at a predetermined value. The voltage regulator 1 further detects the output current of the charging generator 2 and outputs an output signal proportional to the current value.
A current detecting means 12 for emitting 12a; an increasing rate detecting means 14 for detecting an increasing rate of the output signal 12a to detect that the increasing rate exceeds a certain value; and detecting an engine speed to detect the engine speed. Rotation speed detection means 15 for detecting that it is below a certain value
When the number of rotations below a certain value is detected by the number-of-rotations detecting means 15, the output is output when the rate of increase above a certain value is detected by the above-mentioned increase-rate detecting means 14, and the rate of increase above the certain value is not detected. And power generation stop signal 14 in which output is suspended
a to the switch means 11 to turn on and off the switch means 11 and current increase rate control means 19 for feedback controlling the output current so that the increase rate becomes a value corresponding to the constant value. ing. [Operation and Effect] In the voltage regulator 1 having the above-described configuration, when the electric load increases, the switch means 11 is immediately turned on to supply a current to the rotor coil 21 so as to maintain the battery charging voltage at a predetermined value. Accordingly, the output current of the charging generator 2 rapidly increases. The output current is detected by the current detecting means 12, and the increasing rate detecting means 14 detects whether or not the increasing rate exceeds a certain value. When the engine speed is equal to or lower than a certain value, such as when the engine is idling, the power generation stop signal 14a is output when an increase rate of a certain value or more of the output signal 12 is detected, and is output when no increase rate of a certain value or more is detected. Is stopped, and the switch means 11 is turned on and off. Thereafter, when the engine speed is low, the switch means 11 is turned off by the power generation stop signal 14a every time the rate of increase of the output current exceeds a certain value. The rate is kept in an appropriate range, and the engine burden is reduced. Thus, engine stall is prevented. In addition, since the output current is feedback-controlled so that the rate of increase is increased at a substantially constant rate, a sudden change in the engine speed is suppressed, and the amount of power generation increases with an increase in the output current. It can respond to the increase. Example An example of the present invention will be described with reference to the drawings. The voltage regulator 1 has a transistor 11 as a switch means, and the transistor 11 controls ON / OFF of an exciting current of a rotor coil 21 of the vehicle charging generator 2 to adjust a power generation amount of the stator coil 22. The power generation output of the stator coil 22 is a full-wave rectifier 23
And supplied to the battery 3 and the electric load 5 via the battery charging line 31. The charge voltage of the battery 3 is fed back to the voltage regulator 1 via the sensing line 32, is divided by resistance, and is input to the comparator 17. The comparator 17 compares the feedback voltage with the reference voltage VS, and controls the operation of the transistor 11 via the AND gate 18 by the comparison output 17a. Thus, the battery charging voltage is
Is maintained at a constant value irrespective of the fluctuation of the power generation capacity of the power supply and the fluctuation of the electric load 5. The battery charging line 31 is provided with a current detector 12 on the way, and the current detector 12 uses, for example, a Hall element that generates an output according to the magnetic field strength around the charging line to reduce the output current in the charging line 31. Emit a proportional output signal 12a. Output signal 12a
Are input to an increase rate detection circuit 14 via an amplifier 13. The increase rate detection circuit 14 detects an increase rate of the output signal 12a and, when the rate exceeds a certain value (for example, 10 A / sec), generates a power generation stop signal 14a. Power generation stop signal 14a is a NAND gate
Enter in 19. An F / V conversion circuit 15 is provided, and a one-phase output of the stator coil 22 is input to the circuit 15. Above F / V conversion circuit 15
Generates an output 15a corresponding to the frequency of the one-phase output, and this output 15a is proportional to the rotation speed of the rotor coil 21, that is, the engine rotation speed. The output 15a is the comparator 16
Is compared with the constant voltage Va, and when the voltage becomes lower than the constant voltage Va (for example, when the engine speed is 2000 rpm or less), the comparator 16 outputs a “1” level output and the NAND gate 19 opens. In the figure, reference numeral 20 denotes a constant voltage circuit for supplying operating power to each circuit element of the voltage regulator 1, which is connected to the battery 3 via a key switch 4. In the voltage regulator having the above configuration, when the switch 51 is turned on and the large electric load 5 is connected to the battery 3,
The voltage regulator 1 turns on the transistor 11 by the comparison output 17a of the comparator 17 to prevent the battery charging voltage from dropping.
N is activated to supply current to the rotor coil 21. As a result, the output current of the charging generator 2 is rapidly increased, and a sufficient current is supplied to the electric load 5 to prevent a decrease in the battery charging voltage. When the engine is running at a low speed, the sudden increase in the rotor coil current imposes a heavy burden on the engine. put it here,
In the voltage regulator of the present embodiment, when the engine speed is low, the NAND gate 19 is opened by the output of the comparator 16,
The power generation stop signal 14a output when the rate of increase of the output current exceeds a certain value is output as a "0" level output by an AND gate.
The transistor 18 is forcibly turned off by being supplied to 18, thereby suppressing an excessive increase in the output current. Thereafter, the operation of the transistor 11 is controlled by the power generation stop signal 14a, and the output current of the charging generator 2 is feedback-controlled so as to increase at an appropriate rate, and gradually increases without a sudden increase in the power generation amount. Then, the load torque of the charging generator 2 also gradually increases. As a result, engine stall at the time of engine idling or the like is prevented beforehand while responding to an increase in electric load. At the same time, since the output current gradually increases at a substantially constant rate, fluctuations in the idling speed due to fluctuations in the torque of the charging generator 2 can be reduced. When the engine speed increases, the output of the power generation stop signal 14a is prohibited, or when a sufficient current is supplied to the electric load 5 and the battery charging voltage is restored, the power generation stop signal 14a is canceled.
It is controlled by the 17 comparison outputs 17a.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of a voltage regulator according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Voltage regulator 11 ... Transistor (switch means) 12 ... Current detector (current detection means) 14 ... Increase rate detection circuit (increase amount detection means) 15 ... F / V converter (rotation speed detection) Means 16 Comparator (rotational speed detecting means) 2 Vehicle charging generator 21 Rotor coil 3 Battery 31 Battery charging line 5 Electric load

Continuation of the front page (56) References JP-A-60-16195 (JP, A) JP-A-61-165100 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02J 7 / 14-7/24 H02P 9/00-9/48

Claims (1)

(57) [Claims] In a voltage regulator having a switch means for controlling ON / OFF of a rotor coil current of a vehicle charging generator to maintain a battery charging voltage at a predetermined value, an output current of the charging generator is detected and an output proportional to the current value is detected. Current detection means for emitting a signal; increase rate detection means for detecting an increase rate of the output signal to detect that the increase rate has exceeded a certain value; and detecting the engine speed so that the speed is equal to or less than a certain value. A rotation speed detecting means for detecting that the rotation speed is below a predetermined value, and when the rotation speed detection device detects a rotation speed of a predetermined value or less, the rotation speed detection means detects the rotation speed and outputs a constant value. A power generation stop signal that stops the output when an increase rate equal to or greater than the value is not detected is given to the switch means to turn it on and off, and the output current becomes a value whose increase rate corresponds to the constant value. And a current increase rate control means for performing feedback control as described above.