KR0175748B1 - Overvoltage protection circuit of a generator in a car - Google Patents

Abstract

The present invention is to prevent the generator installed in the vehicle from generating an overvoltage and damaging the electrical load.

The present invention is to prevent the over-voltage is generated by blocking the excitation current supplied to the excitation coil with the generator power of the generator when the over-voltage occurs in the generator is provided with a rectifying switching means for rectifying and exciting The excitation current is supplied to the coil, and when an overvoltage is generated, the overvoltage detecting means detects the occurrence of the overvoltage to generate a control signal, and the rectifying switching means does not operate according to the control signal generated by the overvoltage detection unit to excite the excitation coil. By preventing the supply of current, when overvoltage occurs, the excitation current flowing to the excitation coil is very weak and the power generation is stopped, and the restraint torque caused by the operation of the generator is hardly generated in the engine.

Description

Overvoltage prevention circuit of vehicle generator

1 is a control circuit diagram of a conventional vehicle generator.

2 is a control circuit diagram of a vehicle generator by the prevention circuit of the present invention.

(A) and (b) of FIG. 3 are embodiments of the overvoltage detecting means of FIG.

(a) is also an embodiment of using a thyristors as the switching element.

(b) is another embodiment using a transistor as a switching element.

* Explanation of symbols for main parts of the drawings

11 generator 12 rectifier

13 rectification switching means 14 voltage regulator

15: overvoltage detection unit 151: overvoltage detection unit

152: control signal generator STC ₁₁ : stator coil

RTC ₁₁ : female coil SCR _{11 to} SCR ₁₄ : thyristor

BAT ₁₁ : Battery D _11- D ₁₆ : Diode

IGS ₁₁ : ignition switch ZD: constant voltage diode

The present invention relates to an overvoltage generation prevention circuit of a vehicle generator that prevents the generator installed in a vehicle from generating an overvoltage and damaging an electrical load.

The vehicle is equipped with electric loads such as an electric starter and an ignition device, lamps such as a headlamp, a direction lamp, a driving direction indicator lamp, and an air conditioner, and is operated by supplying power to these electric loads. .

The means for supplying electrical loads is the battery.

However, if the battery does not charge the power and continues to be used, the charged power gradually discharges and can no longer supply power.

Therefore, the vehicle includes a generator, and when the engine is driven, the generator is driven together to supply power to the electrical load while charging the battery.

The generator is driven by being connected to the engine by a belt, and the amount of power generated by the generator is different depending on the number of revolutions of the engine, and also depends on the current flowing through the excitation coil.

When the amount of power generated by the generator is less than the electrical load, that is, the amount of electricity used by the electrical load, the battery is discharged and supplied. When the amount of generated power is greater than the electrical load, the generator's generated power is supplied to all the electrical loads. The electricity is charged in the battery.

When the charge voltage of the battery is higher than the rated voltage of the battery, not only the battery is overcharged and damaged, but also the overload is applied to the electrical load and damaged.

Therefore, the generator is provided with a voltage regulator detects the amount of power generated by the generator, and controls the amount of power generated by controlling the current flowing through the excitation coil of the generator according to the detected amount of generated power.

In other words, when the amount of power generated by the generator is large, the current flowing through the excitation coil is reduced, and when the amount of generation is small, the rated power is always charged to the battery while increasing the amount of power generated by increasing the current flowing into the excitation coil, The rated voltage is always supplied.

In addition, the generator is provided with a power supply bypass means, and the power supply bypass means operates when the overvoltage continues to be controlled even by the voltage regulator so that the overvoltage is not supplied to the electrical load.

This conventional technique will be described in detail with reference to the drawings of FIG.

1 is a control circuit diagram of a conventional vehicle generator. As shown in FIG. 2, the generator 1 driving together with the engine to generate power when the engine is driven, and the generated power output from the stator coil STC ₁ of the generator 1 are diodes D _{1 to} D ₆ . Rectified by the first rectifier (2) for supplying the battery (BAT ₁ ) and the electrical load, and the power generation output from the stator coil (STC ₁ ) of the generator 1 rectified with diodes (D ₇ ~ D ₉ ) The second rectifier 3 for supplying an excitation current to the excitation coil RTC _{1 of} the generator 1, and the generator _{1 with} the charging power of the battery BAT ₁ at an initial stage when the generator 1 operates. The ignition switch IGS ₁ for supplying an initial exciting current to the excitation coil RTC _{1 of} the generator 1 and the excitation of the generator 1 according to a power level output from the generator ₁ and charged in the battery BAT ₁ . A voltage regulator 4 for controlling an excitation current flowing through the coil RTC ₁ to adjust an amount of power generation; Determining the occurrence of overvoltage at the power level output from the generator 1 and charged in the battery BAT ₁ , and by the power bypass means 5 for bypassing the generated power of the generator 1 when overvoltage occurs. Configured.

The power supply bypass means 5 includes a relay controller 5A for outputting a drive signal when an overvoltage is generated, a relay RY driven according to an output signal of the relay controller 5A, and the relay RY. When it is connected to the power supply of the generator 1 is configured as a relay switch (RYS) to flow through the resistor (R ₁ ) to the ground.

In the drawing description of FIG. _1, reference numeral IGL ₁ denotes a charge indicator lamp.

In the conventional control circuit configured as described above, when the engine is started and the ignition switch IGS ₁ is connected, the charging power of the battery BAT ₁ is generated through the ignition switch IGS ₁ and the charge indicator lamp IGL ₁ . The charge indicator lamp IGL ₁ is turned on while flowing to the exciting coil RTC _{1 of} ( ₁ ).

In this state, when the engine is normally driven and the generator ₁ operates, power is generated from the stator coil STC ₁ of the generator 1 in accordance with the excitation current flowing through the excitation coil RTC ₁ . The power is rectified and output by the first rectifying unit 2 and the second rectifying unit 3.

The power rectified by the second rectifier 3 is to supply a sufficient excitation current to the excitation coil (RTC ₁ ), the generator 1 performs a normal power generation operation, the charge indicator lamp (IGL ₁ ) is turned off do.

The power rectified by the first rectifying unit 2 is charged in the battery BAT ₁ , and is supplied to the electrical load as operating power.

In this state, the voltage regulator 4 detects the level of power supplied by the first rectifying unit 2 and charged in the battery BAT ₁ and supplied to the electrical load, and according to the detected level of power. (4) controls the exciting current flowing through the exciting coil (RTC ₁ ) of the generator (1) so that the rated voltage is charged in the battery (BAT ₁ ), and supplied to the electrical load.

The relay control unit 5A of the power bypass unit 5 determines whether an overvoltage is generated at the level of the power supplied to the battery BAT ₁ and rectified by the first rectifying unit 2. .

At this time, when an overvoltage occurs, the relay controller 5A outputs a relay driving signal, and the relay RY is driven according to the output relay driving signal, so that the relay switch RYS is connected.

Then, it is rectified in the first rectifying unit 2 and charged in the battery BAT ₁ , and the power supplied to the electric low load is bypassed to the ground through the resistor R ₁ and the relay switch RYS sequentially. Therefore, the battery BAT ₁ and the electrical load are supplied with a rated voltage.

However, the above-described conventional technique bypasses all of the generated overvoltages to ground when overvoltages occur, and thus the generator continues to take a lot of load, thereby causing the restraint torque unnecessary to the engine, as well as resistance to high voltages (R _1). Bypassing to ground through), an expensive resistor (R ₁ ) with a large power capacity must be used, and also has a problem that a large size leads to a large installation area, heat generation, and separate wiring work. .

In addition, when an overvoltage occurs and a relay switch (RYS) is connected and opened, a surge voltage is generated, and the generated surge voltage is applied to the surrounding electrical load, thereby degrading durability of the electrical load.

Accordingly, an object of the present invention is to provide an overvoltage generation prevention circuit of a vehicle generator which prevents an overvoltage by blocking an excitation current supplied to an excitation coil as a generator power source when an overvoltage occurs in a generator.

The overvoltage generation prevention circuit of the vehicle generator of the present invention for achieving the above object is provided with a rectifying switching means for supplying the excitation current to the rectifier and the excitation coil of the rectifier switching means for the generator power supply of the generator, when the overvoltage is generated The detection means detects the occurrence of the overvoltage to generate a control signal, and prevents the rectifying switching means from operating according to the control signal generated by the overvoltage detector so as not to supply the exciting current to the excitation coil.

Therefore, according to the present invention, when overvoltage occurs, the excitation current flowing to the excitation coil is very weak, and the power generation is stopped, and the restraint torque caused by the operation of the generator is hardly generated in the engine.

Hereinafter, an overvoltage generation prevention circuit of a vehicle generator according to the present invention will be described in detail with reference to the accompanying drawings of FIGS. 2 and 3.

2 is a control circuit diagram of a vehicle generator by the prevention circuit of the present invention.

As shown in FIG. 2, generators 11 driven together to generate power when the engine is driven, and generated power output from the stator coil STC ₁₁ of the generator ₁₁ include diodes D _{11 to} D _16. ) Rectified by the rectifier 12 for supplying the battery BAT ₁₁ and the electrical load, and the power generation output from the stator coil (STC ₁₁ ) of the generator 11 to rectify the excitation coil (RTC11) of the generator 11 ) And the rectifier switching means 13 which is cut off according to a control signal when an overvoltage is generated and does not supply an excitation current, and the battery BAT ₁₁ at an initial stage when the generator 11 operates. Ignition switch IGS ₁₁ for supplying an initial exciting current to the excitation coil RTC _{11 of} the generator ₁₁ with a charging power of a power supply), and a power level output from the generator ₁₁ and charged in the battery BAT ₁₁ . According to the excitation of the generator 11 One (RTC ₁₁₎ exciting voltage regulator 14 for adjusting the power generation amount by controlling the current flowing to and from the generator 11 determines the occurrence of over-voltage to the level of the power source rectified by the rectifying switching means 13 over-voltage In this case, the overvoltage detecting means 15 is configured to generate a control signal and to make the rectifying switching means 13 shut off.

Here, the rectifying switching means 13 rectifies the generated power output from the stator coil STC ₁₁ of the generator 11 by using the thyristors SCR _{11 to} SCR ₁₃ , and controls the overvoltage detecting means 15. When the signal is output at low potential, the thyristors SCR _{11 to} SCR ₁₃ are cut off.

(A) of FIG. 3 is a circuit diagram showing an embodiment of the overvoltage detecting means of FIG.

In connection with a resistor (R _11, R ₁₂₎ to the output terminal of the rectifying switching means 13, as shown in series, grounding the connection point of the resistors (R _11, R _12), a capacitor (C ₁₁₎ and constant voltage diodes ( The cathode of ZD) was connected to constitute an overvoltage detector 151.

The anode of the constant voltage diode ZD is connected to the gate of the thyristor SCR ₁₄ , which is a switching element, and the cathode of the thyristor SCR ₁₄ is grounded.

The resistors R ₁₃ and R ₁₄ are connected in series to the output terminal of the rectifying switching means ₁₃ , and the anode of the thyristor SCR ₁₄ is connected to the connection points of the resistors R ₁₃ and R ₁₄ . the connection point thereof formed the thyristor control signal generating section 152 connected to the gate of the (SCR ₁₁ ~SCR ₁₃₎ of the rectifying switching means 13.

In the drawing description of FIG. 2, reference numeral IGL ₁₁ is a charge indicator lamp, and PTR is a power transistor.

When the overvoltage generation prevention circuit of the vehicle generator of the present invention configured as described above starts the engine and connects the ignition switch IGS ₁₁ , the charging power of the battery BAT ₁ is changed to the ignition switch IGS ₁₁ and the charge indicator lamp ( The charge indicator lamp IGL ₁₁ is turned on while flowing through the IGL ₁₁ ) to the excitation coil RTC ₁₁ of the generator 11.

In this state, when the engine is normally driven and the generator ₁₁ operates, power is generated from the stator coil STC ₁₁ of the generator 11 according to the excitation current flowing through the excitation coil RTC ₁₁ . The power is rectified and output by the rectifier 12 and the rectifier switching means 3.

The power rectified by the rectifier switching means 3 is to supply a sufficient excitation current to the excitation coil (RTC ₁₁ ) of the generator 11, the generator 11 performs a normal power generation operation, the charge indicator lamp ( IGL ₁₁ ) goes out.

The power rectified by the rectifier 12 is charged in the battery BAT ₁₁ and supplied to the electrical load as the operating power.

In this state, the voltage regulator 14 detects the level of the power rectified by the rectifying unit 12 and charged in the battery BAT ₁₁ and supplied to the electrical load, and the voltage regulator 14 according to the detected level of the power. ) Controls the excitation current flowing through the excitation coil RTC ₁₁ of the generator 11 while controlling the power transistor PTR so that the rated voltage is charged to the battery BAT ₁₁ and supplied to the electrical load.

The rectified power output from the rectifying switching means 13 is input to the overvoltage detecting unit 151 of the overvoltage detecting means 15, divided by resistors R11 and R12, and applied to the cathode of the constant voltage diode ZD. .

Here, when overvoltage occurs, the values of the resistors R ₁₁ and R ₁₂ are set such that the voltage applied to the cathode of the constant voltage diode ZD is equal to or higher than the zener voltage thereof.

Then, when no overvoltage occurs, the constant voltage diode ZD is cut off, and thus the thyristor SCR ₁₄ is cut off, and is output from the rectifying switching means 13 so as to output the resistors R ₁₂ and R. _{The high potential} divided by ₁₄ ) is outputted as a control signal, and the thyristors SCR _{11 to} SCR 13 of the rectifying switching means ₁₃ are triggered by the output high-potential control signal to maintain the conduction state. The power generation power output from the stator coil STC ₁₁ of the generator 11 is rectified, and an excitation current is supplied to the excitation coil RTC ₁₁ .

In such a state, when an overvoltage occurs and the voltage divided by the resistors R ₁₁ and R ₁₂ becomes equal to or higher than the Zener voltage of the constant voltage diode ZD, the constant voltage diode ZD becomes conductive and, conversely, the thyristors The trigger signal is applied to the gate of SCR ₁₄ .

Then, the thyristor SCR ₁₄ is brought into a conducting state, and the power divided by the resistors R ₁₃ and R ₁₄ flows to the ground through the thyristor SCR ₁₄ , so that the thyristor of the rectifying switching means 13 is reduced. (SCR _{11 to} SCR ₁₃ ) are not triggered and enter the cutoff state.

Thus, when a thyristor (SCR ₁₁ ~SCR ₁₃₎ has a cut-off state of the rectifying switching means 13, and prevents the generation power output from the rectifier skater coil (STC ₁₁₎ of the generator 11, because of this Since the excitation current cannot be supplied to the excitation coil RTC ₁₁ , the power generation operation of the generator 11 is stopped.

(B) of FIG. 3 is a circuit diagram showing another embodiment of the overvoltage detecting means of FIG.

As shown therein, another embodiment of the present invention uses transistor Q instead of thyristor SCR ₁₄ as the switching element.

Thus another embodiment of the present invention will have not generated an overvoltage zener diode (ZD) is applied with the low potential to the base of the transistor (Q) on when a cut-off state in which the resistance, so that he Off (R _13, R ₁₄ ) is partitioned a high potential is output to the control signal by means of, which results thyristors (SCR ₁₁ ~SCR ₁₃₎ the stator coil (STC ₁₁ of the generator 11, while still maintaining the conduction state of the rectifying switching means 13 Rectification of the generated power output from the) and supply the exciting current to the excitation coil (RTC ₁₁ ).

In such a state, when an overvoltage occurs and the voltage divided by the resistors R ₁₁ and R ₁₂ becomes equal to or higher than the Zener voltage of the constant voltage diode ZD, the constant voltage diode ZD becomes in a conductive state in contrast to the above and the transistor ( Since a low potential is applied to the base of Q), the transistor Q is turned on, and the power divided by the resistors R ₁₃ and R ₁₄ flows to the ground through the transistor Q.

Therefore, being able to rectify the generated power output from the stator coil (STC ₁₁₎ of the thyristor (SCR ₁₁ ~SCR ₁₃₎ is in a blocking state the generator 11 does not trigger switching of the rectifying means 13, a woman Since the excitation current is not supplied to the coil RTC ₁₁ , the power generation operation of the generator 11 is stopped.

As described above, in the present invention, when the overvoltage is generated in the generator, the excitation current is cut off to suppress the generation of the overvoltage. The unnecessary restraint torque is not applied to the engine, and no surge voltage is generated, which does not affect the durability of the electrical load.

Claims (7)

When the engine is driven, the generator 11 which is driven together to generate power, and the generated power output from the stator coil STC ₁₁ of the generator 11 are rectified by the diodes D _{11 to} D ₁₆ to generate a battery BAT. ₁₁ ) and the rectifier 12 for supplying the electrical load and the power generation power output from the stator coil (STC ₁₁ ) of the generator 11 to supply an exciting current to the excitation coil (RTC ₁₁ ) of the generator 11. And the rectifier switching means 13 which is cut off according to the control signal when the overvoltage is generated and does not supply the excitation current, and the generator by the charging power of the battery BAT ₁₁ at the beginning of the operation of the generator 11. The generator _{11 according to} an ignition switch IGS ₁₁ for supplying an initial exciting current to the exciting coil RTC _{11 of} FIG. ₁₁ and a power level output from the generator 11 and charged in the battery BAT11. woman of the excitation coil flows into (RTC ₁₁₎ The voltage regulator 14 controls the amount of power generated by controlling the flow, and the generator 11 determines the occurrence of the overvoltage at the level of the power rectified by the rectifier switching means 13 and generates a control signal when the overvoltage is generated. And overvoltage detection means (15) which generates and turns the rectifying switching means (13) into a shut-off state. The rectification switching means (13) according to claim 1, wherein the rectifier switching means (13) rectifies power generation power output from the stator coil (STC ₁₁ ) of the generator (11), and outputs a control signal at a low potential from the overvoltage detection means (15). Overvoltage generation prevention circuit of a vehicle generator, characterized in that it comprises a thyristors (SCR ₁₁ ~ SCR ₁₃ ) to be cut off. 2. The overvoltage detecting means (15) according to claim 1, wherein the overvoltage detecting means (15) includes an overvoltage detecting portion (151) for detecting the occurrence of overvoltage with the output voltage of the rectifying switching means (13), and the overvoltage generating means (151) for detecting the occurrence of overvoltage. In this case, the switching device generates a switching signal, and the rectifying switching device 13 operates normally with the output voltage of the rectifying switching device 13, and when the overvoltage is detected, the rectifying device according to the output signal of the switching device. An over-voltage generation prevention circuit of a vehicle generator, characterized in that the control means for generating a switching unit (152) for the switching means (13). 4. The overvoltage generation prevention circuit of a vehicle generator according to claim 3, wherein the switching element is a thyristor (SCR ₁₄ ). 4. The overvoltage generation prevention circuit of a vehicle generator according to claim 3, wherein the switching element is a transistor (Q). 4. The overvoltage generation prevention circuit of a vehicle generator according to claim 3, wherein the charge indicator lamp is continuously lit when an overvoltage occurs. 4. The overvoltage generation prevention circuit of a vehicle generator according to claim 3, wherein the charging indicator lamp is repeatedly turned on and off when an overvoltage occurs.