CN201398070Y - Circuit to prevent reverse battery polarity - Google Patents

Abstract

The utility model relates to a polarity protection circuit, in particular to a polarity protection circuit used in a charging system for preventing battery polarity reverse connection. The circuit for preventing reverse polarity of the storage battery includes: a relay whose control terminal is connected to the output terminal of the charger and the first access terminal of the storage battery, and whose control terminal is connected to the negative pole of the polarity diode and the output terminal of the photocoupler ; Polarity diode, the positive pole of which is connected to the first access terminal of the battery, and the negative pole is connected to the control terminal of the relay; the positive pole of the output terminal of the photocoupler is connected to the control terminal of the relay, and the negative pole of the output terminal is connected to the second access terminal of the battery , and its input end is connected to the power-on circuit of the charger. The utility model adopts the above technical scheme, on the one hand, it effectively avoids the danger caused by the battery polarity reverse connection in the charging system, and on the other hand, it avoids the discharge loss of the battery when there is no AC power supply or power-on signal.

Description

Circuit to prevent reverse battery polarity

technical field

The utility model relates to a polarity protection circuit, in particular to a polarity protection circuit used in a charging system for preventing battery polarity reverse connection.

Background technique

Batteries can store DC power. In communication and power systems, they are often used as backup equipment to avoid sudden power failures when the system power fails. For example, in UPS, the battery pack with a certain backup time is connected to the charger. When the mains power is normal, it will supply power to the load after rectification and inversion, and the battery will be charged by the charger at the same time; The inverter supplies power and converts it into AC power for the load. Therefore, the battery plays a very important role in the power system. However, because it stores a large amount of electric energy, there are also safety issues in use, and serious accidents such as short-circuit explosions will occur if the operation is not careful. Therefore, the positive and negative wiring of the battery must be correct. Therefore, a polarity protection circuit must be designed to prevent battery polarity reverse connection in the equipment to avoid safety accidents. The traditional anti-reverse connection circuit generally uses the reverse cut-off characteristic of the diode to connect it in series in the battery connection circuit to achieve the effect of anti-reverse connection; however, the protection effect is single and the control degree is weak. The devices can be connected and controlled together to better protect the battery and achieve the purpose of timely charging and discharging. In addition, it can be realized by using a polarity protection circuit composed of electronic switch tubes. For example, the patent "circuit with reverse polarity protection of power supply" with the publication number of 1355607 connects the field effect transistor for protection with the substrate of the components in the protected circuit. The protection field effect transistor is a PMOS field effect transistor or an NMOS field effect transistor. If it is PMOS, its gate and source are respectively connected to the ground terminal and power supply terminal of the protected circuit, and its drain is connected to the substrate of the PMOS element in the protected circuit. If it is NMOS, its gate and source are respectively connected to the power terminal and ground terminal of the protected circuit, and its drain is connected to the substrate of the NMOS element in the protected circuit. Once the polarity of the power supply of the protected circuit is reversed, the protective field effect tube will form an open circuit to prevent the current from burning the field effect tube components in the circuit and protect the overall circuit. Another example is the patent "NMOS battery reverse connection protection" with publication number 1832285, which includes a voltage source, which includes positive and negative terminals. The polarity sensitive device has a first terminal in communication with the positive terminal of the voltage source and includes a second terminal. A low resistance switch communicates with the first and second terminals of the voltage source and communicates with the second terminal of the polarity sensitive device. The low resistance switch assumes a conductive state between the second terminal of the polarity sensitive device and the negative terminal of the voltage source when the first voltage at the positive terminal of the voltage source minus the second voltage at the negative terminal of the voltage source is greater than the threshold voltage. Otherwise, the low resistance switch assumes a non-conductive state. However, these circuits are implemented by electronic switching tubes, and if they are used in high-power power supply systems, high-power field effect tubes need to be selected, and the cost is relatively high.

Utility model content

In view of this, the utility model proposes a polarity protection circuit for preventing battery polarity reverse connection in the charging system, the cost of which is not high, and the protection function is more effective than that of a single-polarity diode.

The technical scheme of the utility model is:

Circuits to prevent reverse battery polarity, including:

A relay, whose controlled terminal is connected to the output terminal of the charger and the first access terminal of the storage battery, and whose control terminal is connected to the negative pole of the polarity diode and the output terminal of the photocoupler;

polarity diode, its anode is connected to the first access terminal of the storage battery, and its cathode is connected to the control terminal of the relay;

In the photoelectric coupler, the positive pole of the output terminal is connected to the control terminal of the relay, the negative pole of the output terminal is connected to the second access terminal of the storage battery, and the input terminal is connected to the power conduction circuit of the charger.

Further, a current-limiting resistor is connected in series at any position on the branch formed by the first access terminal of the storage battery, the polar diode, the control terminal of the relay, and the output terminal of the photocoupler.

Furthermore, the current limiting resistor is connected between the control terminal of the relay and the positive pole of the output terminal of the photocoupler.

Further, the input end of the photocoupler is also connected in series with a current limiting resistor.

Preferably, the relay described in the utility model is an electromagnetic relay.

The utility model adopts the above technical scheme, on the one hand, effectively avoids the danger caused by battery polarity reverse connection in the charging system, and on the other hand, avoids the discharge loss of the battery when there is no AC power supply or power-on signal.

Description of drawings

Figure 1 shows a typical circuit diagram of an uninterruptible power supply (UPS);

What Fig. 2 showed is the circuit diagram of the utility model.

Detailed ways

The utility model is further described now in conjunction with accompanying drawing and specific embodiment.

Referring to Figure 1, it is a typical circuit diagram of an AC inverter uninterruptible power supply (UPS). Usually, the AC power is rectified by AC/DC and then charged to the battery through the charger. Once a power failure occurs, the battery will output AC power through the inverter.

Referring to Fig. 2, the circuit for preventing battery polarity reverse connection of the present invention includes: a relay D3, whose controlled terminal is connected to the output terminal of the charger and the first access terminal BAT+ of the battery BAT1, whose control terminal is connected to Connect the negative pole of the polar diode D2 and the output terminal of the photocoupler D1; the positive pole of the polar diode D2 is connected to the first access terminal BAT+ of the storage battery BAT1, and the negative pole is connected to the control terminal of the relay D3;

The positive pole of the output terminal of the photocoupler D1 is connected to the control terminal of the relay D3, the negative pole of the output terminal is connected to the second access terminal BAT- of the battery BAT1, and its input terminal is connected to the power supply circuit of the charger. A signal terminal with a voltage output that can be taken from a charger's circuit.

Further, a current-limiting resistor R3 is connected in series at any position on the branch formed by the first access terminal BAT+ of the battery BAT1, the polar diode D2, the control terminal of the relay D3, and the output terminal of the photocoupler D1. In the embodiment of the present utility model, the current limiting resistor R3 is connected between the control terminal of the relay D3 and the positive pole of the output terminal of the photocoupler D1.

Similarly, the input terminal of the optocoupler D1 is also connected in series with a current limiting resistor R4 for current limiting.

Preferably, the relay D3 described in the present utility model is an electromagnetic relay. The control terminal is the two ends of the coil, and the controlled terminal is the switch terminal composed of the movable contact terminal (normally open terminal), the static contact terminal (normally closed terminal) and the common terminal.

In this way, the connection circuit between the battery BAT1 and the charger is controlled by the control terminal voltage of the relay D3. Only when the auxiliary circuit is turned on, can the relay D3 be closed, and the charger can charge the battery BAT1. That is, the positive pole of the battery BAT1 is connected to the first access terminal BAT+, and the negative pole of the battery BAT1 is connected to the second access terminal BAT-, in order to conduct the connection between the charger and the battery BAT1. However, if the polarity of the battery BAT1 terminal is reversed, the diode D2 will not conduct, the auxiliary circuit of the relay D3 will not have current flow, the relay D3 cannot be closed, and the charger cannot be input to the battery terminal. On the other hand, even if the polarity of the battery BAT1 is connected correctly, if the charger has no AC output or no switch signal, the optocoupler D1 will not work, the circuit will not be conducted, and the relay D3 will still not be closed; Discharge loss of battery BAT1 in case of signal.

Although the utility model has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that, without departing from the spirit and scope of the utility model defined by the appended claims, changes in form and details may be made. Making various changes to the utility model is within the protection scope of the utility model.

Claims (5)

1. prevent the circuit of accumulator polarity reversal connection, it is characterized in that: comprise

Relay (D3), its controlled terminal are connected to the output of charger and first incoming end (BAT+) of storage battery (BAT1), and its control end is connected to the negative pole of polarity diode (D2) and the output of photoelectrical coupler (D1); Polarity diode (D2), its anodal first incoming end (BAT+) that inserts storage battery (BAT1), negative pole is connected to the control end of relay (D3);

Photoelectrical coupler (D1), the positive pole of its output is succeeded the control end of electrical equipment (D3), and the negative pole of output connects second incoming end (BAT-) of storage battery (BAT1), and its input inserts the power turn-on circuit of charger.

2. the circuit that prevents the accumulator polarity reversal connection according to claim 1 is characterized in that: the arbitrary position on the branch road that the control end of first incoming end (BAT+) of described storage battery (BAT1), polarity diode (D2), relay (D3), the output of photoelectrical coupler (D1) constitute is connected in series a current-limiting resistance (R3).

3. the circuit that prevents the accumulator polarity reversal connection according to claim 2 is characterized in that: described current-limiting resistance (R3) inserts between the positive pole of the output of the control end of relay (D3) and photoelectrical coupler (D1).

4. the circuit that prevents the accumulator polarity reversal connection according to claim 1 is characterized in that: the input of described photoelectrical coupler (D1) also is connected in series a current-limiting resistance (R4).

5. the circuit that prevents the accumulator polarity reversal connection according to claim 1 is characterized in that: described relay (D3) is an electromagnetic relay.

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