KR19990032282U - Cutoff Relay Circuit for DC Generator - Google Patents

Abstract

The present invention relates to a cut-off relay circuit for a DC generator which protects the battery from DC overcurrent and overvoltage and prevents the charging voltage of the battery from being discharged back to the generator, the power supply line 90; A blocking circuit for cutting off the power line (90); An overcurrent sensing circuit 100 configured to set a delay time that the system can withstand the overcurrent when the sensing current detected from the power line 90 is overcurrent and to drive the blocking circuit when the corresponding delay time has elapsed; And an overvoltage sensing circuit 200 for driving the blocking circuit when an overvoltage occurs by comparing a supply voltage with a rated voltage.

Therefore, the present invention can increase the reliability and stability of the equipment because the present invention can adjust the overcurrent value and the cutoff time by the user.

Description

Cutoff Relay Circuit for DC Generator

The present invention relates to a cut-off relay circuit installed between a DC generator and a battery, in particular, a DC power generation that protects the battery from overcurrent and overvoltage and prevents the charge voltage of the battery from being discharged back to the generator. The present invention relates to a cutoff relay circuit for a machine.

Cut-off relays are installed in all power supply circuits where a direct current generator is used to provide stable power to the system. An example of such a cutoff relay circuit is shown in FIG. 1. The cutoff relay circuit shown in FIG. 1 is installed between the DC generator 1 and the storage battery 5 and used for charging a stable storage battery.

That is, a current sensing sensor 2 is installed in a power supply line for transferring power generated from the DC generator 1 to the storage battery 5, and the sensing voltage converted into voltage by the current sensing sensor 2 is converted into a voltage. After dividing through the variable resistor VR ₁ , the transistor Q ₁ is energized when the divided sensing voltage exceeds the reference voltage compared to the reference voltage. When the transistor is energized in this way, power is applied to the relay coil 4 connected to the emitter terminal of the transistor to prevent the overcurrent from being applied to the storage battery 5 by opening the contact b. In addition, the voltage supplied from the generator 1 and the voltage flowing into the storage battery 5 are applied to each input terminal of the OP amplifier OP2 to compare the voltage levels. If the supply voltage on the generator 1 side is smaller than the inflow voltage on the battery 5 side, the OP amplifier OP1 displays a logic high to operate the transistor Q1 to operate the relay coil 4. The power supply line is opened to prevent the reverse discharge of the voltage from the storage battery 5 to the generator 1.

In the conventional relay circuit described above, there is a problem that the user cannot arbitrarily control the overcurrent value and the control time, so that stable supply of power is impossible. For example, if the rated current is 100A, the control time should be different when the overcurrent values are 120A, 200A and 300A. That is, 120A means to cut off the power after 2 minutes, 200A to cut off the power after 1 minute, and 300A means to cut off the power after 30 seconds. In general, even in excess of overcurrents in any system, the uniform control of them is due to the system's flexibility, which prevents a stable supply of power.

In addition, in the conventional relay circuit, there is a problem that the system cannot be protected from overvoltage.

Accordingly, the present invention was devised to solve the problems of the prior art as described above, and an object of the present invention is to provide flexibility in overcurrent control by adding a delay time in proportion to the level of overcurrent generated and to add an overvoltage protection function. To provide a relay circuit.

The present invention to achieve the above object is the power line 90; A blocking circuit for cutting off the power line (90); An overcurrent sensing circuit 100 configured to set a delay time that the system can withstand the overcurrent when the sensing current detected from the power line 90 is overcurrent and to drive the blocking circuit when the corresponding delay time has elapsed; And an overvoltage sensing circuit 200 for driving the blocking circuit when an overvoltage occurs by comparing a supply voltage with a rated voltage.

In addition, the overcurrent sensing circuit 100 of the present invention detects the overcurrent and converts it into a voltage signal and outputs the current sensor 20, and a plurality of variables for distributing the converted voltage to a voltage level suitable for comparing with the reference voltage. The resistors VR ₁₀ , VR ₂₀ , VR ₃₀ , a plurality of comparison circuits OP ₁₀ , OP ₂₀ , OP ₃₀ coupled with the variable resistors for comparing the divided voltage and the reference voltage are referenced to When the voltage exceeds the system is characterized in that it comprises a time delay circuit (110, 111, 112) is operated after being delayed by a time that can withstand the overcurrent.

Other objects and advantages of the present invention will be described below and will be appreciated by the embodiments of the present invention. In addition, the object and advantages of the present invention can be realized by means and combinations shown in the appended utility model registration claims.

1 shows the configuration of a conventional cut-off relay circuit.

Fig. 2 shows the configuration of a cut-off relay circuit for a direct current generator according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1, 10: DC generator 5, 50: storage battery

20: current sensor 30: reference voltage generator

40: drive switch 60: auxiliary relay

70: operation check light 80: main relay

100: overcurrent detection circuit 110, 111, 113: timer circuit

120, 121, 122: latch circuit 200: overvoltage detection circuit

300: voltage comparison circuit

VR10, VR20, VR30, VR40: Variable Resistors

Q1: switching transistor

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the description of the present invention, the same or equivalent parts as in the prior art will be described with the same reference numerals.

Looking at the configuration of the present invention with reference to Figure 2, the power supply line 90 is installed between the DC generator 10 and the storage battery 50, the b contact of the main relay 80 in the center of the power supply line 90 This is installed. The b contact is operated in conjunction with the main relay 80 coil and is closed when the main relay 80 coil is excited, and has a characteristic of opening when the element is closed. Therefore, the power supplied to the storage battery 50 is turned on / off according to the small and the excitation of the main relay 80 coil.

In addition, a current sensor 20 is installed at any point between the generator 10 and the main relay 80 b contact. The current sensor 20 is a current transformer for detecting the primary current by measuring the secondary current by winding the primary and secondary coils around the magnetic core using a donut-shaped magnetic core, Hall element in the magnetic continuity generated by the current And the Hall element method for detecting the strength of the magnetic field, that is, the strength and weakness of the current by measuring the Hall voltage, and the fuse method having a different melting time for the current. In this embodiment, a Hall element type LEM sensor is used.

The sensing current sensed by the current sensor 20 is converted into a voltage and applied to three variable resistors VR ₁₀ , VR ₂₀ , and VR ₃₀ . Since the three variable resistors are connected in parallel to each other, the applied input voltages are the same, whereas the set resistance values of the variable resistors are different from each other, so that the output voltages distributed are different from each other. Therefore, even if the same applied voltage is applied to the variable resistor, the output voltage appearing at the output side thereof is different from each other.

The output voltages of the variable resistors are applied to one input terminal of the OP amplifiers OP ₁₀ , OP ₂₀ , and OP ₃₀ , and are compared with a reference voltage applied to the other input terminal. The OP amplifier compares the distribution voltage of the variable resistor with the reference voltage from the reference voltage generator 30 and operates the timer circuits 110, 111, and 112 connected to the output terminal when the distribution voltage is larger.

The timer circuits 110, 111, and 112 operate after a set delay time, and there are a digital method of using a charge and discharge time of RC and a frequency of a basic oscillator. In particular, since the circuit configuration of the method using the charging and discharging time of RC is simple, it is widely used as a simple timer. There are a timer circuit using an FET and a timer circuit using a thyristor. In the timer circuits 110, 111, and 112 applied to the present embodiment, any of the above schemes may be used.

Latch circuits 120, 121, and 122 are coupled to the output terminals of the timer circuits 110, 111, and 112, and the latch circuits function to maintain the generation state even if an overcurrent condition occurs even once. .

The outputs of the latch circuits 120, 121, and 122 are branched so that one side is connected to the base terminal of the switching transistor Q ₁₀ and the other side is an overcurrent alarm lamp (LED ₁ , LED ₂₎ for informing the outside that an overcurrent has occurred. , LED ₃ ). The overcurrent alarm lamp is composed of a light emitting diode (LED).

Transistor Q ₁₀ , which is connected to the output terminals of the latch circuits 120, 121, 122, is for switching, its selector terminal is grounded, and its emitter terminal is connected to the auxiliary relay 60 coil. The contact a linked to the auxiliary relay 60 is connected to the coil of the main relay 80. The contact a is an open contact in the state in which the auxiliary relay 60 is turned off and closed in the excited state.

As described above, the overcurrent detecting circuit 100 which detects an overcurrent state of the power supply line 90 and cuts off the power supply line 90 after a delay time proportional to the magnitude exceeding the rating includes a current sensing sensor 20 and a variable resistor. (VR ₁₀ , VR ₂₀ , VR ₃₀ ), OP amplifiers OP ₁₀ , OP ₂₀ , OP ₃₀ , timer circuits 110, 111, 112, and latch circuits 120, 121, 122.

In addition, the embodiment of the present invention divides an arbitrary point between the current sensor 20 and the generator 10 and connects it to the variable resistor VR ₄₀ to divide the voltage and divide the divided voltage with the reference voltage. In comparison, when the reference voltage is smaller, an overvoltage sensing circuit 200 for energizing the transistor Q ₁₀ is included.

It is also possible to insert a latch circuit between the OP amplifier OP ₄₀ and the transistor Q _{10 of} the overvoltage sensing circuit 200. In this case, as in the overcurrent sensing circuit 100, the overvoltage is generated.

In addition, the embodiment of the present invention branched an arbitrary point between the generator 10 and the current sensor 20 to input the generator-side applied voltage to one terminal of the OP amplifier (OP ₅₀ ), the power line 90 Branch at any point between the power diode (D ₁₀ ) and the battery 50 and input the voltage of the battery 50 side to the other terminal of the OP amplifier (OP ₅₀ ) to the voltage of the generator 10 side and the battery 50 And a voltage comparison circuit 300 for comparing the voltages. Therefore, when the voltage of the battery 50 side is greater than the voltage of the generator 10 side, the transistor Q ₁₀ connected to the OP amplifier OP ₅₀ is energized to cut off the power supply line 90 to the battery 50. The reverse discharge from can be prevented.

In this case, since the comparison is made using the voltage of the cathode terminal side of the power diode D ₁₀ , it does not operate normally. (A voltage drop of about 0.7 V occurs at the diode.) The anode terminal of the power diode D ₁₀ . An operation check lamp 70 is installed on the side to indicate that power is being supplied to the power supply line 90 to the outside. It also helps you figure it out.

In the above configuration of the present embodiment, in particular, the operation of the overcurrent sensing circuit 100 will be described by way of example. First, the resistance values of the variable resistors VR ₁₀ , VR ₂₀ , VR _{30 of the} overcurrent sensing circuit 100 are first set. do. If the rating is 100A, VR ₁₀ sets its resistance to exceed the reference voltage at 120A, VR ₂₀ sets its resistance to exceed the reference voltage at 200A, and VR ₃₀ exceeds the reference voltage at 300A. Set the resistance value so that it Therefore, when the current sensor 20 senses 120A, the timer circuit 110 coupled to VR ₁₀ is operated, and the remaining timer circuits 111 and 112 are not operated. This also applies to 200A and 300A.

In addition, the delay time is set in the timer circuits 110, 111, and 112 connected to the variable resistors VR ₁₀ , VR ₂₀ , and VR ₃₀ . In this case, the timer circuit 110 connected to the VR ₁₀ is 2 minutes, the timer circuit 111 connected to the VR ₂₀ is 1 minute, and the timer circuit 112 is connected to the VR ₃₀ 30 seconds. Set it.

When setting of the variable resistors VR ₁₀ , VR ₂₀ , VR ₃₀ and the timer circuits 110, 111, 112 is completed, the driving switch 40 is operated to excite the main relay 80 coil. As the main relay 80 coil is excited, its a contact is closed, and power generated in the generator 10 is transferred to the storage battery 50. At this time, if an overcurrent of 200A exceeding the rating occurs in the power supply line 90, the current sensor 20 detects it, converts it into a voltage signal, and outputs the converted voltage (VR ₁₀ , VR ₂₀ , VR). ₃₀ ). The voltage divided by each of the variable resistors VR ₁₀ , VR ₂₀ , VR ₃₀ is applied to the OP amplifiers OP ₁₀ , OP ₂₀ , OP ₃₀ and compared with the reference voltage of the reference voltage generator 30. At this time, since only the voltage divided by the VR ₂₀ is larger than the reference voltage, only the timer circuit 111 coupled with the VR ₂₀ is operated. Therefore, when the one minute time set in this timer circuit 111 elapses, the contact of the timer circuit 111 is turned on and the output is applied to the latch circuit 121. The latch circuit 121 drives the switching transistor Q ₁₀ in a state of continuously maintaining an output applied from the timer circuit 111. The transistor Q ₁₀ excites the auxiliary relay 60 coil to open its b contact and element the main relay 80 coil connected to the b contact.

As the main relay 80 coil is demagnetized as described above, the contact a is opened to prevent the overcurrent generated from the generator 10 from being transferred to the storage battery 50.

As described above, the overcurrent sensing circuit 100 of the present invention provides flexibility according to the specifications of the system by varying a delay time of turning off the power according to the magnitude of the overcurrent generated. This is because, depending on the system, even if an overcurrent exceeding the rating occurs, no loss occurs for a certain time. That is, the delay time of the timer circuit is determined by setting the time that the system can withstand according to the magnitude of the generated overcurrent.

The above-described embodiment is described by taking an example of installing the relay circuit of the present invention between a DC generator and a storage battery. Therefore, the present invention can be applied to all systems powered by a direct current generator.

The present invention is not limited to the above-described embodiment, and various modifications within the equivalent scope of the technical concept of the present invention and the utility model registration claims to be described below by those skilled in the art to which the present invention belongs. Of course, variations are possible.

As described above, the present invention can increase the reliability and stability of the equipment because the user can adjust the overcurrent value and the cutoff time. In addition, an overvoltage protection circuit is added to enable stable use without a separate protection circuit.

Claims (6)

A power line 90; A blocking circuit for cutting off the power line (90); An overcurrent sensing circuit 100 configured to set a delay time that the system can withstand the overcurrent when the sensing current detected from the power line 90 is overcurrent and to drive the blocking circuit when the corresponding delay time has elapsed; And Cut-off relay circuit for a direct current generator, characterized in that it comprises an overvoltage detection circuit for driving the cut-off circuit when the overvoltage occurs by comparing the supply voltage with the rated voltage. The method of claim 1, wherein the overcurrent detecting circuit 100 A current detection sensor 20 for detecting an overcurrent and converting it into a voltage signal and outputting the converted signal; A plurality of variable resistors VR ₁₀ , VR ₂₀ , VR ₃₀ for distributing the converted voltage to a voltage level suitable for comparison with a reference voltage; A plurality of comparison circuits (OP ₁₀ , OP ₂₀ , OP ₃₀ ) coupled with each of the variable resistors to compare the divided voltage and the reference voltage; And a time delay circuit (110, 111, 112) operated after the system is delayed by an amount of time to withstand the overcurrent when the distribution voltage exceeds the reference voltage. The method of claim 2, And a latch circuit on the output side of the time delay circuit, wherein the overcurrent sensing circuit maintains the overcurrent state. The method of claim 2, Cut-off relay circuit for a direct current generator, characterized in that the overcurrent detection circuit 100 includes an overcurrent alarm lamp (LED ₁ , LED ₂ , LED ₃ ) for indicating the occurrence of the over current to the outside. The method of claim 1, wherein the blocking circuit And a main relay 80 installed in the power line 90, an auxiliary relay 60 for driving the main relay 80, and a switching transistor Q ₁ for driving the auxiliary relay 60. Cut-off relay circuit for direct current generator. The method of claim 5, Cut-off relay circuit for a direct current generator, characterized in that the driving of the switching transistor (Q ₁ ) is controlled by the overvoltage detection circuit (200), the overcurrent detection circuit (100) and the voltage comparison circuit (300).