JPH0427778B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a voltage adjustment device for a storage battery charging generator installed in an automobile, etc., and particularly a voltage adjustment device suitable for use in combination with a high-output generator. Regarding equipment.

[Background of the invention]

The conventional voltage regulator for charging generators
As described in No. 22542, a switching transistor 17 suppresses the malfunction of the charging alarm. However, switching transistor 1
When the electrical resistance from the main rectifier 3 to the electrical load 5 is large because the base current that drives the main rectifier 3 is supplied from the auxiliary rectifier 6.

When the output current of the generator is large.

When the alternating current ripple of the generator's output voltage increases by rectifying the neutral point output.

Since the voltage drop between the auxiliary rectifier and the battery increases and the base current of the transistor 17 increases, the Zener diode 10 becomes conductive at low battery voltage, resulting in a decrease in the apparent regulated voltage.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a voltage regulating device for a charging generator that prevents malfunction of a charging alarm and reduces the drop in regulating voltage.

[Summary of the invention]

The present invention eliminates the influence of the base current by current amplifying the divided voltage of the first voltage divider circuit with an emitter follower, so that even if the output voltage of the auxiliary rectifier is higher than the storage battery voltage, the apparent adjustment voltage is reduced. This is to prevent it from decreasing.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a circuit diagram of a charging system including a generator driven by an engine (not shown).

In Figure 1, 1 is the armature winding of the generator, 2
2b is a neutral point rectifier that rectifies the harmonic pulsating voltage at the neutral point of armature winding 1 to increase the output current. , 3 is a field winding that supplies magnetic flux to the armature winding 1, and 4 is connected to the output ends of the three-phase full-wave rectifier 2a and the neutral point rectifier 2b, and is connected to the electric load 5 via a switch 22. A storage battery 6 that supplies current is an auxiliary rectifier that supplies field current to the field winding 3. 7 is a voltage regulator;
divider resistors 8, 9, Zener diode 1
0, transistor 11, resistor 12, power transistor 13, flywheel diode 1
4, a current amplifying transistor 15, and second voltage dividing resistors 16 and 17. 18 is a charging indicator light, and 19 is a key switch. 20
is a capacitor, and 21 is a load changeover switch.

In the above configuration, when the key switch 19 is turned on, the storage battery 4 is transferred to the key switch 19, the charging indicator light 18, the field winding 3, and the power transistor 1.
3 through which the initial excitation current flows. Next, when the generator starts rotating, a voltage is generated in armature winding 1,
The field current flows through the auxiliary rectifier 6 and enters a self-exciting state, and the generated output charges the storage battery 5 via the three-phase full-wave rectifier 2a.

When the generated voltage is low and the voltage of the storage battery 4 is low at the same time, a voltage dividing resistor 8, which divides the voltage of the storage battery 4,
The voltage at the voltage dividing point of the transistor 15 is lower than the voltage at the voltage dividing point of the voltage dividing resistors 16 and 17.
The emitter voltage, the Zener voltage of the Zener diode 10, and the base-emitter voltage of the transistor 11 cannot be overcome, so the transistor 11 is cut off, the power transistor 13 is conductive, and the field coil 3 is energized. . As the field current increases, the generated voltage also increases, and the voltage of the storage battery 4 increases. Then, the voltage at the voltage dividing point of the voltage dividing resistors 8 and 9 is higher than that at the base of the transistor 15.
Overcoming the emitter voltage, the Zener voltage of the Zener diode 10, and the base-emitter voltage of the transistor 11, the transistors 15 and 11 conduct, the power transistor 13 is cut off, and the field current passes through the flywheel diode 14. Attenuate. When the field current decreases, the output voltage of the generator decreases, and the voltage of the storage battery 4 also decreases. By repeating the above operations, the voltage of the storage battery 4 is controlled to a constant value.

In this device, the transistor 15 functions as a current amplifier, and when the transistor 15 is conductive, current is mainly supplied from the voltage dividing point of the second voltage dividing resistors 16 and 17. Therefore, the resistance values of the first voltage dividing resistors 8 and 9 can be set to a value sufficiently larger than 16 and 17. This means that the time constant of the smoothing circuit formed by the resistors 16, 17 and the capacitor 20 can be increased, and even when the ripple applied to the storage battery 4 due to the operation of the neutral point rectifier 26 is large, the first partial voltage A smoothed voltage is transmitted to the voltage dividing points of the resistors 8 and 9. Furthermore, the output voltage of the auxiliary rectifier 6 (L terminal voltage: hereinafter referred to as V _L ) is due to the voltage drop between the output voltage of the three-phase full-wave rectifier 2a (B terminal voltage: hereinafter referred to as V _B ) and the storage battery 4. Therefore, if the voltage becomes higher than the storage battery voltage (S terminal voltage: hereinafter referred to as V _S ), the voltage at the dividing point of the second voltage dividing resistors 8 and 9 may become higher; Since the fluctuation of the collector current due to the fluctuation of the collector voltage is small, the influence on the adjustment voltage is also small. Therefore, according to the present circuit, there is no drop in the regulated voltage due to fluctuations in the base current in the conventional circuit, and a voltage regulator with good voltage control characteristics can be realized.

Next, the operation of this device when the storage battery 4 is in a fully charged state will be explained using FIG.

Assume that the storage battery 4 is in a fully charged state and the electrical load 5 is a large current load. Figure 2 is
This is a diagram showing the time course of V _S and V _L. When the switch 21 is abruptly turned off at time t ₁ , the exciting current attenuates through the flywheel diode 14, but due to the inductance of the field winding 3, the current Values cannot change rapidly. Therefore, both V _S and V _L temporarily become high voltages, but the voltage of V _L decreases with a time constant of about 0.3 seconds as the field current decreases. On the other hand, in the case of V _S , the storage battery 4 is in a fully charged state, so the discharge time constant is as long as about 2 seconds. V _L reaches V _L1 when time t ₂ has elapsed. At this time, the collector voltage of the transistor 15 becomes lower than the emitter voltage, so the transistor 15 is cut off, the Zener diode 10 and the transistor 11 are cut off, and the power transistor 13 is turned on. Then, the field current is energized and V _L increases. When V _L rises above V _L1 , the collector current of transistor 15 is supplied again, transistor 15, Zener diode 10, and transistor 11 become conductive, power transistor 13 is cut off, the field current decreases, and V _L decreases. By repeating the above,
V _S > V _S1 : While the relationship is regulated voltage, V _L is regulated to the voltage V _L1 .

When V _S =V _S1 at time t ₃ , the base current of transistor 15 stops flowing, power transistor 13 becomes conductive, and V _L increases. At the time (t ₄ ) when V _L =V _S , the normal voltage control state is returned to, and the voltage of the storage battery 4 is adjusted to the regulated voltage V _S1 .

According to this embodiment, it is possible to prevent a drop in the regulated voltage due to voltage ripples, and the value of V _L does not fall below a certain value even when the electrical load is abruptly cut off, thereby preventing the charging indicator light 15 from being erroneously lit. There is an effect that can be achieved.

FIG. 3 shows another embodiment of the invention. Reference numeral 7 in FIG. 3 is a voltage regulator, which will be explained below in place of the voltage regulator 7 in FIG.

The circuit shown in FIG. 3 differs from that shown in FIG. 1 in that a transistor 22 and a resistor 23 are added; other than that the configuration is the same as the embodiment shown in FIG. With the same symbol,
Detailed explanation will be omitted. In the circuit of FIG. 3, transistor 22 acts as an emitter follower and has the following advantages compared to the circuit of FIG.

The base current flowing from the voltage divider circuit (resistors 8, 9) to the voltage detection circuit (Zener diode 10) further decreases, and the voltage divider resistors 8, 9
The resistance value can be increased, the ripple absorption rate is improved, and the drop in the adjustment voltage due to load is further reduced.

The base-emitter voltage of the transistor 22 is added to the voltage detection circuit, the temperature gradient of the storage battery adjustment voltage (change in adjustment voltage with respect to minute temperature changes) becomes negative, and the temperature compensation of the storage battery charging voltage is optimized. Ru. This will be explained using specific numerical values.

Now, set the regulation voltage V _S1 to 14.5V, and set the Zener voltage V _z of the Zener diode to 6.5V,
Transistor base-emitter voltage drop V _BE
is 0.65V. Then, the voltage dividing ratio γ of the voltage dividing resistors 8 and 9 can be obtained as follows.

γ=V _S1 /V _Z +3・V _BE ≒1.72 ...(1) On the other hand, V _S1 can be written as follows using γ.

V _S1 = γ・(V _Z +3・V _BE ...(2) If the temperature coefficient of V _Z is 1 mV/℃ and the temperature coefficient of V _BE is -2 mV/℃, the temperature coefficient of V _S1 is ∂V _S1 /∂T=1.72・{1+3・(−2)}=−8.6mV/°C.

Applying the same numerical values to the circuit shown in Figure 1, we get
Similar to the above, ∂V _S1 /∂T=−5.6 mV/° C. is obtained.

It is desirable for the temperature gradient of the adjustment voltage to be about -7 to -15 mV/°C from the viewpoint of charging performance of the storage battery, and this embodiment satisfies this condition.

Further, according to the present invention, since the neutral point ripple can be removed by a simple circuit, it is possible to prevent the adjustment voltage of the storage battery voltage from decreasing, and it is effective to eliminate insufficient charging of the storage battery. . In particular, the above-mentioned drop in the regulated voltage is noticeable when the power generation capacity of the charging generator is increased using technology such as a neutral point rectifier, so the effect of improving the charging performance by taking the measures according to the present invention is significant. To give an example,
In combination with a 12V, 100A generator with an armature core outer diameter of 139mm, at a rotation speed of 5000r/m, a voltage drop of 0.5V was observed at 90% of the rated output in the conventional circuit. The circuit shown in Figure 1 improves the voltage to 0.25V.

Furthermore, according to the present invention, the problem of erroneous lighting of the charging indicator lamp 15 does not occur, so that the reliability of the charging system can be improved.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a voltage regulating device for a charging generator that prevents malfunction of a charging alarm and stabilizes the regulating voltage.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a charging generator according to the present invention, FIG. 2 is an explanatory diagram showing the operating voltage of the charging generator according to FIG. 1, and FIG. 3 is a circuit diagram of a voltage regulator according to another embodiment of the present invention. It is a diagram. 1... Armature winding, 2a... Three-phase full-wave rectifier,
2b... Neutral point rectifier, 3... Field winding, 4...
Storage battery, 5... Electric load, 6... Auxiliary rectifier, 7
... Voltage adjustment circuit, 10 ... Zener diode, 18 ... Charging indicator light, 19 ... Key switch, 15 ... Transistor.

Claims (1)

[Scope of Claims] 1. A charging generator equipped with an armature winding and a field winding, a main rectifier that rectifies the output of the charging generator and supplies current to an electrical load including a storage battery, an auxiliary rectifier that rectifies the output of the charging generator and supplies exciting current to the field winding; a first voltage divider circuit that divides the output voltage from the storage battery or the main rectifier; a voltage adjustment circuit that detects the voltage at a voltage dividing point of the voltage circuit via a constant voltage element and controls the excitation current flowing through the field winding to adjust the voltage of the storage battery to a constant value; and the auxiliary rectifier. In a charging power generation device having a charging alarm connected between an output terminal and the storage battery via a key switch, a second voltage dividing circuit for dividing the output voltage is provided at the output terminal of the auxiliary rectifier; A current amplifying transistor having a collector connected to a voltage dividing point of the voltage dividing circuit, a base connected to the voltage dividing point of the first voltage dividing circuit, and an emitter connected to the constant voltage element is provided, and the constant voltage element is connected to the voltage dividing point of the first voltage dividing circuit. The voltage dividing circuit is characterized in that it is configured to be electrically connected when the voltage dividing point voltage of the second voltage dividing circuit and the voltage dividing point voltage of the first voltage dividing circuit become higher than a predetermined specified voltage. Voltage regulator for charging generator. 2. In claim 1, the current amplifying means includes a first transistor having a base connected to a voltage dividing point of a first voltage dividing circuit and a collector connected to an output terminal of an auxiliary rectifier via a resistor. and a second transistor, the base being connected to the emitter of the transistor, the collector being connected to the voltage dividing point of a second voltage dividing circuit, and the emitter being connected to a constant voltage element. Voltage regulator. 3. The voltage regulating device for a charging generator according to claim 1, wherein the amplifier circuit is constructed by connecting two or more transistors in a Darlington configuration.