JPS6019489Y2 - Vehicle power supply circuit device - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a vehicle power supply circuit device, particularly a vehicle power supply circuit device equipped with a battery connected via a backflow prevention means by a DC generator mounted on the vehicle, which is destroyed due to overvoltage. An overcurrent breaker and an overvoltage short circuit device are connected to the power supply line, and the occurrence of an overvoltage condition on the power supply line is converted into an overcurrent condition. The present invention relates to a vehicle power supply circuit device that protects a load connected to the power supply line.

In vehicles such as automobiles, a DC generator driven by the engine (including when rectifying the output of an AC generator)
is installed, and a power supply circuit system is adopted in which the battery is floatingly charged by the DC generator while the engine is rotating.

In recent years, electronic circuits have been increasingly used in electrical equipment in such vehicles, and semiconductor elements such as transistors and thyristors are increasingly being incorporated.

However, this type of semiconductor device does not have sufficient resistance to surge voltages that occur when a battery is floating-charged and disconnected while a DC generator is rotating, or overvoltage caused by various causes. often destroyed.

For example, when a small refrigerator using an electromagnetically driven vibrating compressor is installed in a bus or leisure vehicle, a DC-AC inverter is used to drive the vibrating compressor, but switching transistors may be damaged due to surge voltage or overvoltage. Destruction occurs.

This requires rapid removal of overvoltage conditions.

On the other hand, in the electrical equipment for vehicles mentioned above, there are loads such as lamps for night lighting that cannot tolerate even a relatively short power outage, and in order to eliminate the above-mentioned overvoltage state, even a temporary power outage is caused. It is necessary to avoid this.

This invention aims to solve the above points,
It is an object of the present invention to provide an overvoltage protection device for electronic circuit devices that are easily destroyed by surge voltage or overvoltage in electrical equipment mounted on a vehicle.

In general, overvoltage protection devices employ means to bypass the overvoltage when an overvoltage occurs, but in order to reduce the short circuit capacity of the bypass means, the overvoltage state is replaced with an overcurrent state, and an overcurrent breaker is used to circuit the DC voltage circuit. The purpose is to liberate the.

This will be explained below with reference to the drawings. Figure 1 is an explanatory diagram explaining the basic concept of the overvoltage protection device used in the present invention, Figure 2
The figure shows an embodiment of an overvoltage short-circuit device used in the present invention to short-circuit terminals when an overvoltage occurs, and FIG. 3 is an explanatory diagram of the overvoltage protection device shown in FIG. 1 to prevent reverse polarity connection. 4 shows the circuit configuration of an embodiment of the vehicle power supply circuit device of the present invention, and FIG. 5 shows an explanatory diagram illustrating its operating state.

In FIG. 1, 1 is a breaker, 2 is an overvoltage short circuit device, 3 is a DC-AC conversion inverter, and 4 is a resonant layer electromagnetically driven compressor.

In normal times, power is supplied to the resonance layer electromagnetic drive compressor 4 via the DC-AC conversion inverter 3.
If a surge voltage or overvoltage occurs on the power supply side,
As will be described later (Fig. 2), the overvoltage short circuit device 2 responds to bypass the overvoltage applied to the load side, converts the overvoltage state into an overcurrent state, and releases the circuit by the breaker 1. As a result, the overvoltage applied to the load side It is designed to protect against surge voltage or overvoltage being supplied.

That is, the short circuit current caused by the overvoltage short circuit device 2 is transferred to the breaker 1.
By selecting an overvoltage level sufficient to activate the overvoltage short-circuit device 2, the breaker 1 is activated when the overvoltage shorting device 2 is activated.

FIG. 2 shows a specific example of the configuration of the overvoltage short circuit device 2 in FIG. 1.

In the figure, numerals 5 and 6 are silices, and numeral 7 is a Zener diode, which are selected so that they remain off under normal voltage conditions and are turned on under overvoltage conditions.

8 is a diode, 9.10 is a capacitor, 11, 12,
13, 14, 15, and 16 are resistors, and 17 is a variable resistor that controls the divided voltage of the resistor 13 applied to the Zener diode.

In the figure, the power supply voltage is divided by resistors 12 and 13,
Although the divided voltage of the resistor 13 is applied to the Zener diode 7, the Zener diode 7 is normally kept in an off state.

However, when an overvoltage occurs, the above divided voltage increases,
Zener diode 7 is turned on.

This triggers the thyristor 6 and turns it on.

Then, the thyristor 5 is further turned on. Therefore, when an overvoltage or surge voltage occurs, the current that was previously supplied to the load will be bypassed by the resistor 11 and thyristor 5, and this bypass current will be considered as a short circuit, and the circuit will be closed by the breaker 1 as described above. To be released.

Note that the resistor 11 is a resistor for limiting the current flowing through the thyristor 5 to a predetermined level.

A capacitor 10 connected in parallel with the thyristor 5 forms a time constant circuit together with a resistor 11, and has the function of turning on the thyristor 5 with a slight delay.

Therefore, it is kept in an immovable state against overvoltage that does not require a short circuit by the overvoltage short circuit device 2, such as a surge voltage that ends instantaneously, and the voltage rise between terminals A and 8 is suppressed by the capacitor 9 for the surge voltage as described above. do.

Fig. 3 shows a diode 18 inserted in parallel on the load side of the overvoltage short-circuit device in Fig. 1, and when the power supply is inserted with the wrong polarity, the diode 18 is turned on, and the short-circuit current causes the breaker to turn on. 1 is cut off.

That is, simply by newly inserting the diode 18, the load side can be protected when an overvoltage or surge voltage occurs as described above, and the load side can also be protected when the power source is inserted with the wrong polarity.

FIG. 4 shows an embodiment of the vehicle power supply circuit device of the present invention. In the figure, the line a is connected to a load mounted on the vehicle, such as a lamp, which is not affected by overvoltage or surge voltage, and the line b is connected to a load mounted on the vehicle, such as a lamp. A load that is easily affected by overvoltage or surge voltage, such as a resonant layer electromagnetic drive compressor with an inverter, is connected to the inverter, and each is used depending on the nature of the load.

Further, 1 is a breaker, 2 is an overvoltage short circuit device, 18 is a diode for preventing reverse polarity connection, 19 is a diode for preventing reverse current, 20 is a field winding of the DC generator G, 21 is a voltage regulator, and 22 is a floating charging battery. , 23 represents a ground side switch of the battery 22.

Furthermore, 24 is a diode, and 25 is a small capacity battery, which are inserted as necessary when a load that requires constant power supply to the b line is connected.

Now, when the breaker 1 is closed, the DC generator is working, the floating charging battery 22 is floatingly charged, and power is being supplied to the load, the overvoltage short circuit device 2 and the diode 18 are connected between circuit points A and B. Power is supplied to the a-line and b-line loads without shorting the lines.

In this state, for example, in case of floating charging or when the ground side switch 23 of the battery 22 is turned off, a surge voltage may be generated from the DC generator.

In that case, as described above, the overvoltage short circuit device 2 short-circuits the circuit points A and B, changes the state to an overcurrent state, and shuts off the breaker 1.

That is, the load connected to the b line is protected from the surge voltage.

The operating state in this case is shown in Figure 5, where a is the waveform of the surge voltage applied to terminal A (Figure 4), b is the current waveform of the overvoltage short circuit device 2, and C is the state of the breaker. each represents.

When a surge voltage as shown by the broken line in FIG. 34 waveform) is absorbed by the overvoltage short circuit device 2.

In Fig. 5, the current waveform of the overvoltage short circuit device 2 rises linearly after the TD time and becomes similar to the surge voltage waveform, but since the DC generator continues to generate power by self-excitation, the overvoltage The current of the short circuit device does not become zero even after the time Ts when the surge voltage ends, but is maintained at a predetermined level.

Then, as shown in FIG. 5C, the breaker 1 changes from the on state to the off state and is cut off after a time T1.

If the breaker 1 is manually or automatically reset after a certain period of time T2 after the surge voltage has ended, the system shown in FIG. 4 can return to its original state and operate normally.

As explained above, according to the present invention, with respect to surge voltages and overvoltages that often occur in DC power supply circuits, the overvoltage short circuit device converts the overvoltage state into an overcurrent state, and the circuit is opened by the breaker, resulting in the load side can be protected from being supplied with surge voltage or overvoltage.

It is also possible to prevent reverse polarity connection of the power supply simply by connecting a diode in parallel to the load side of the overvoltage short circuit device.

Furthermore, since the breaker is cut off after the overvoltage short circuit device initiates a short circuit, it is possible to prevent the semiconductor element of the overvoltage short circuit device from being destroyed and to design a small current capacity.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram explaining the basic concept of the overvoltage protection device used in the present invention, Fig. 2 is an example configuration of the overvoltage short circuit device used in the present invention, and Fig. 3 is the overvoltage protection device shown in Fig. 1. 4 shows the circuit configuration of an embodiment of the vehicle power supply circuit device of the present invention, and FIG. 5 shows an explanatory diagram illustrating its operating state. . In the figure, 1 represents a breaker, 2 represents an overvoltage short circuit device, 3 represents a DC-AC conversion inverter, and 18 represents a diode.

Claims (1)

[Scope of utility model registration request] A DC generator mounted on a vehicle, a battery connected to an output terminal of the DC generator via a backflow prevention means, and an electric circuit load mounted on the vehicle, the battery floating through the backflow prevention means. In a vehicle power supply circuit device in which a switch is inserted in series with the battery while it is being charged, a first power supply line to which a load that is less likely to be destroyed by overvoltage among the electric circuit loads is connected, and a semiconductor that is more likely to be destroyed by overvoltage. A second power supply line to which a load including a circuit is connected is connected, and the battery is connected to the first power supply line, and a line is provided between the first power supply line and the second power supply line. an overvoltage short-circuit device that inserts a resettable overcurrent breaker into the second power supply line and substantially shorts the second power supply line when the voltage of the second power supply line exceeds a predetermined voltage level; A power supply circuit device for a vehicle, characterized in that the overvoltage short circuit device is configured such that the short circuit state is restored by circuit interruption by the resettable overcurrent breaker.