Charger output anti-reverse connection and anti-reverse charging protection device and control method thereof

Abstract

The embodiment of the invention provides a charger output anti-reverse connection and anti-reverse charging protection device and a control method thereof, and belongs to the technical field of charging safety. The device comprises a detection circuit 1, a detection circuit 2, a detection circuit 3, a relay control circuit 1, a relay control circuit 2, an anti-backflow diode, a first relay and a first diode which is arranged on a control coil of the first relay in an anti-parallel mode, and a second relay and a second diode which is arranged on the control coil of the second relay in an anti-parallel mode. Wherein the detection circuit 1 is used for detecting a voltage signal of an output end of the charger, the detection circuit 2 is used for detecting voltage polarity of a battery end, the detection circuit 3 is used for detecting an output current signal of the charger, and the relay control circuit 1 is used for controlling connection and disconnection of an output first relay. The relay control circuit 2 is used for controlling connection and disconnection of the second relay. According to the scheme of the invention, effective protection of battery reverse connection and current backflow is realized, and the reliability and safety of the system are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of charging safety, and in particular to a protection device for preventing reverse connection and backflow of a charger output and a control method for the protection device for preventing reverse connection and backflow of a charger output. Background Art

[0002] At present, there are many charger output reverse connection protection circuits in the industry, but most of them use the method of controlling the opening or closing of MOS by detecting the voltage polarity at the output end, so as to effectively protect the output end from the reverse connection of the battery; such circuits are relatively expensive and have relatively large losses when outputting large currents or high voltages. In medium and high voltage outputs, especially when the output current reaches tens of amperes or more, a controlled and adapted medium and high voltage DC contactor or high voltage DC relay is also connected in series at the output end. The disadvantage of this method is that the space volume is large and the cost is high, resulting in inflexible and inconvenient use; there is no effective and reliable control of the contactor or DC relay, which may cause electric shock damage, adhesion or damage to the contactor and relay under special circumstances. When the output relay is connected (normally energized or sticky), if the output voltage of the charger is lower than the voltage of the external rechargeable battery, the battery will discharge to the charger output, that is, the battery current will be reversed. If the output electrolytic capacitor fails and short-circuits, or the output rectifier diode fails and short-circuits, the battery may be damaged or the printed circuit board and other components may be damaged due to the abnormally large current. The anti-reverse-reverse diode has a certain forward conduction voltage drop under normal charging conditions, especially when the charging current is large, there is a large conduction loss. At the same time, a corresponding heat sink needs to be added to the diode to ensure that the thermal stress meets the requirements. Summary of the invention

[0003] In view of the above problems, an embodiment of the present invention aims to provide a protection device for preventing reverse connection and reverse injection of a charger output and a control method thereof.

[0004] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a protection device for preventing reverse connection and reverse feeding of a charger output, and the method includes: a detection circuit 1, a detection circuit 2, a detection circuit 3, a relay control circuit 1, a relay control circuit 2, an anti-reverse feeding diode, a first diode in reverse connection on a first relay and a control line package, and a second diode in reverse connection on a second relay and a control line package; wherein the detection circuit 1 is used to detect the voltage signal at the output end of the charger, the detection circuit 2 is used to detect the voltage polarity at the battery end, the detection circuit 3 is used to detect the output current signal of the charger, the relay control circuit 1 is used to control the attraction and disconnection of the output first relay, and the relay control circuit 2 is used to control the attraction and disconnection of the second relay.

[0005] Optionally, the anode of the anti-backflow diode is connected to the positive terminal of the charger output, and the cathode is connected to a contact of the second relay and a contact of the first relay; based on controlling the attraction and disconnection of the second relay, the conduction loss on the anti-backflow diode is reduced.

[0006] Optionally, the negative end of the charger output is connected to one end of the detection circuit 3, and the detection circuit 3 is used to detect the output current and send a signal to the main control unit circuit to monitor the output current condition and control the attraction and disconnection of the second relay according to the output current signal.

[0007] Optionally, one end of the control line package of the output first relay is connected to the power supply and the cathode of the first diode, and the other end is connected to the relay control circuit 1; the relay control circuit 1 controls the attraction and disconnection of the first relay according to the battery voltage polarity detection signal.

[0008] Optionally, one end of the control coil of the second relay is connected to the power supply and the cathode of the second diode, and the other end is connected to the relay control circuit 2; the relay control circuit 2 is used to control the attraction of the second relay when it is detected that the output current exceeds the set value.

[0009] The second aspect of the present invention provides a control method for a protection device for preventing reverse connection and backflow of a charger output. The method is implemented by the above-mentioned control system for preventing reverse connection and backflow of a charger, and the method comprises: detecting the voltage polarity of the battery by a detection circuit 2, and when it is detected that the battery is reversely connected, keeping the first relay in a disconnected state to achieve battery reverse connection protection; when the battery is normally connected and the difference between the internal output voltage of the charger and the battery voltage is lower than a set value, controlling the first relay to be energized to start the charging process.

[0010] Optionally, when charging is started, the voltage signal at the output end of the charger is monitored by the detection circuit 1 to ensure that the two contacts are opened with zero voltage when the first relay is energized.

[0011] Optionally, the method also includes: detecting the output current of the charger through the detection circuit 3, and when it is detected that the output current is greater than a preset value, controlling the second relay to be energized to short-circuit the anti-backflow diode; when it is detected that the output current is abnormally a backflow current, quickly disconnecting the second relay to avoid damage to the charger and the battery caused by the backflow current.

[0012] Optionally, the closing and opening operations of the second relay are implemented through a main control unit circuit, and the main control unit drives and controls the second relay according to a current signal provided by the detection circuit 3 .

[0013] Optionally, the main control unit circuit is used to process signals from each detection circuit and control the closing and opening of the first relay and the second relay.

[0014] Through the above technical scheme, the scheme of the present invention realizes effective protection against battery reverse connection and current backflow by reasonably controlling the attraction and disconnection of the charger output relay, and significantly improves the reliability and safety of the system. The zero-voltage attraction operation of the relay reduces the damage to the relay contacts caused by instantaneous current and prolongs the life of the components. The loss of the anti-backflow diode is effectively reduced, which improves the overall energy efficiency and reduces the heat dissipation demand. In addition, the main control unit circuit realizes intelligent management during the charging process, including standby, slow start, normal operation and shutdown functions, ensuring the efficient and safe operation of the charger under different working conditions.

[0015] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0017] Figure 1 It is a principle block diagram of a protection device for preventing reverse connection and reverse injection of a charger output provided by an embodiment of the present invention;

[0018] Figure 2 This is a circuit diagram of an embodiment provided by an implementation scheme of the present invention;

[0019] Figure 3 This is another circuit diagram of an embodiment of the detection circuit 3 provided in one embodiment of the present invention using a Hall current sensor to detect the output current. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0021] Figure 1 1 is a block diagram of a protection device for preventing reverse connection and reverse injection of a charger output provided by an embodiment of the present invention. Figure 1As shown, an embodiment of the present invention provides a protection device for preventing reverse connection and reverse feeding of a charger output, the device comprising: a detection circuit 1, a detection circuit 2, a detection circuit 3, a relay control circuit 1, a relay control circuit 2, an anti-reverse feeding diode (VD2), an output relay (K1) and a first diode (VD1) reversely connected on its control line package, a normally open relay (K2) and a second diode (VD3) reversely connected on its control line package; wherein the detection circuit 1 is used to detect a voltage signal at the output end of the charger, the detection circuit 2 is used to detect a voltage polarity at the battery end, the detection circuit 3 is used to detect an output current signal of the charger, the relay control circuit 1 is used to control the closing and opening of the output relay, and the relay control circuit 2 is used to control the closing and opening of the normally open relay.

[0022] For chargers with output voltages from low voltage to high voltage, a general normally open AC relay or high voltage DC relay K1 can be selected. By detecting the voltage Vbat_P at the battery terminal of the charger, since GND_D is the working ground, the voltage difference between the positive terminal Vbat_P of the battery and the negative terminal Vbat_N of the battery is Vbat_P. By judging the positive and negative polarity of the battery terminal voltage Vbat_P, the on and off of the relay K1 is controlled. When the battery terminal voltage Vbat_P is detected to be negative, that is, the battery is connected reversely, the relay K1 is maintained in the off state, and the on and off of the relay K1 can be controlled. To achieve output reverse connection protection; when the battery is connected normally, it is necessary to detect the internal output voltage Vout_P of the charger and the voltage Vbat_P of the positive terminal of the battery at the same time. By calculating the voltage difference between the two, the relay K1 is only energized when the voltage difference between the two is low enough, such as when the voltage difference is less than 0.2V, to ensure that the two contacts of the relay K1 are opened at zero voltage. This can greatly reduce the current flowing through the contacts of the relay K1 when the relay K1 is energized, avoid adhesion, damage or damage to the relay due to excessive current, and improve the reliability of the circuit.

[0023] Furthermore, an anti-backflow diode VD2 is connected in series at the output end to prevent the battery from current backflow or abnormally large current in normal working mode and when the charger output is abnormal, which not only improves the reliability of the output relay, but also prevents the internal components or circuits of the charger from being burned due to excessive current, thereby improving the protection of the battery and improving the reliability of the battery.

[0024] When the anti-backflow diode VD2 is normally turned on, especially when the conduction current is large, the normally open relay K2 is attracted to short-circuit the current passing through the anti-backflow diode VD2, thereby greatly reducing the loss of the anti-backflow diode, and also greatly reducing the thermal stress on the backflow diode, and greatly reducing the heat sink used to dissipate heat from the anti-backflow diode VD2.

[0025] Specifically, the anode of the anti-backflow diode VD2 is connected to the charger output Vout_P, a contact of the normally open relay K2 and one end of the detection circuit 1, the cathode of the diode VD2 is connected to another contact of the normally open relay K2, a contact of the normally open relay K1, and the other contact of the relay K1 is connected to the battery positive terminal Vbat_P and one end of the detection circuit 2.

[0026] Furthermore, the negative output terminal Vout_N of the charger is connected to the other end of the detection circuit 3, the other end of the detection circuit 3 is connected to the other end input of the detection circuit 1, the other end input of the detection circuit 2 and Vbat_N, and Vbat_N is connected to the working ground GND_D.

[0027] Furthermore, one end of the relay K1 control coil is connected to the cathode of the diode VD1 and the power supply VCC, and the other end of the relay K1 control coil is connected to the anode of the diode VD1 and the relay control circuit 1.

[0028] Furthermore, one end of the control coil of the relay K2 is connected to the cathode of the diode VD3 and the power supply VCC, and the other end of the control coil of the relay K2 is connected to the anode of the diode VD3 and the relay control circuit 2.

[0029] Furthermore, the detection circuit 1 detects the voltage Vout_P between the motor output Vout_P and the working ground GND_D, and the detection circuit 2 detects the voltage between the battery positive terminal Vbat_P and the battery negative terminal Vbat_N as Vbat_P, and the voltage Vbat_P is the battery voltage.

[0030] Further, the relay control circuit 1 controls the closing and opening of the relay K1;

[0031] Further, the relay control circuit 2 controls the closing and opening of the relay K2;

[0032] Furthermore, the detection circuit 3 detects the output current of the charger, and the current signal is sent to the main control unit circuit. The main control unit performs calculations on the current signal and then sends a corresponding control signal to the relay control circuit 2.

[0033] In addition, the signals detected by the detection circuit 1 and the detection circuit 2 need to be sent to the main control unit circuit of the charger, and the main control unit circuit of the charger needs to judge the positive and negative polarity of the battery voltage Vbat_P. When the battery is reversed, the relay K1 is kept in the disconnected state to achieve anti-reverse connection protection; when the battery is connected normally, the main control unit circuit of the charger needs to compare the output Vout_P and the battery voltage Vbat_P and reasonably control the closure of the relay K1 according to the requirements; the output current signal detected by the detection circuit 2 needs to be sent to the main control unit circuit of the charger, and the main control unit circuit of the charger performs calculation and judgment on the detection signal, and gives a signal to close the relay K2 when the output current of the charger is greater than a preset value; the main control unit circuit of the charger simultaneously controls and realizes the standby mode, output slow start, normal operation and shutdown functions of the charger. The specific judgment, calculation comparison, communication or other control functions of the main control unit circuit of the charger are not elaborated here.

[0034] Furthermore, the preferred working principle and control method of the present invention are specifically described as follows:

[0035] After the charger main control unit works normally, the detection circuit 2 first detects the voltage Vbat_P at the battery end. When the battery is reversely connected, the detection circuit 2 will detect that the voltage Vbat_P is negative. In this case, the control relay circuit will maintain the disconnected state of the relay K1, so that the reverse connection of the battery will not cause any adverse effect on the reliability of the charger, and the charger output reverse connection protection is realized;

[0036] When the battery is connected normally, the detection circuit 2 detects that the voltage Vbat at the battery end is positive. The main control unit of the charger performs a slow output start when it detects that other conditions are normal. When the internal output voltage Vout of the charger rises to about 1V lower than the battery voltage Vbat, the main control unit circuit of the charger sends a normal closure signal to the relay control circuit, and the relay K1 is closure, thereby achieving zero voltage closure of the two contacts of the relay K1, effectively limiting the current flowing through the contacts of the relay K1 when the relay K1 is closure, avoiding adhesion, damage or damage to the relay due to excessive current, and then the charger charges the battery normally. In theory, when the internal output voltage Vout of the charger rises to below the battery voltage, the relay K1 is closure, because the anti-backflow diode VD2 can prevent the battery current from backflowing, and the relay K1 is basically zero current but not zero voltage closure at the moment of closure. This control method is also possible, but it is not as reliable as the relay closure method that ensures that the voltage between the two contacts is basically zero.

[0037] An anti-backflow diode VD2 is connected in series at the output end to prevent the battery current from backflowing in normal working mode and when the charger output rectifier diode or filter capacitor is abnormally short-circuited.

[0038] The detection circuit 3 detects the output current of the charger. This output current signal needs to be sent to the main control unit circuit of the charger. The main control unit circuit of the charger calculates and judges the detection signal. When the output current of the charger is greater than a preset value (such as 0.5A), it gives a signal to close the normally open relay K2. At the same time, it is best for the main control unit circuit to set the output current limit point to be slightly greater than 0.5A (such as 1A), so that the two contacts of the normally open relay K2 short-circuit the anti-reverse feeding diode VD2, and the two contacts of the normally open relay K2 are zero voltage energized. At the moment when the normally open relay K2 is energized, there will be no excessive instantaneous charging current, and the anti-reverse feeding diode VD2 The current flowing through is basically zero, and then the main control unit circuit gradually increases the current limit value of the output charging current to the required maximum current limit value, thereby greatly reducing the loss of the anti-backflow diode VD2 and the heat dissipation requirement of the anti-backflow diode VD2; when the output rectifier diode or output electrolytic capacitor inside the charger fails and shorts, the detection circuit 3 will immediately detect the backflow current signal, and the main control unit quickly gives a control signal to disconnect the relay K2, so that the anti-backflow diode enters and exits the output circuit to prevent current backflow, so it can prevent battery current backflow, which not only protects the battery itself but also prevents the further spread of the internal circuit fault of the charger.

[0039] In one possible implementation, reference Figure 2 , the relay K1 and the relay K2 are both normally open relays, the internal output positive terminal Vout_P of the charger is connected to the anode of the diode VD2, one contact of the relay K2 and one end of the resistor R3, the cathode of the diode VD2 is connected to the other contact of the relay K2 and one contact of the relay K1, the other contact of the relay K1 is connected to the positive terminal Vbat_P of the battery and one end of the resistor R5, the other end of the resistor R3 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to one end of the resistor R16 and one end of the capacitor C5 to generate a sampling signal Vout_SE of the internal output voltage of the charger, the other end of the resistor R16 and the other end of the capacitor C5 are connected to the working ground GNDS_A;

[0040] Further, the other end of the resistor R5 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to one end of the resistor R10, the other end of the resistor R10 is connected to one end of the resistor R9, one end of the resistor R15, one end of the capacitor C6 and the 5th pin of the in-phase input of the operational amplifier D1, the other end of the resistor R9 is connected to the power supply +3.3VDC, the other end of the capacitor C6, the other end of the resistor R15, one end of the capacitor C4, one end of the resistor R17, the 4th pin of the operational amplifier D1, one end of the capacitor C2 and one end of the capacitor C4 are all connected to the working ground GNDS_A, and the capacitor C The other end of resistor R17 is connected to one end of resistor R14, the other end of resistor R14 is connected to one end of resistor R12, the other end of resistor R12 is connected to the other end of resistor R13, one end of resistor R6, one end of capacitor C3 and the reverse input pin 6 of op amp D1, the other end of capacitor C3 is connected to the other end of resistor R6, one end of resistor R4 and the output pin 7 of op amp D1, the other end of resistor R4 is connected to the other end of capacitor C2 and generates a battery voltage detection signal Vbat_SE.

[0041] Furthermore, the negative terminal of the battery Vbat_N is connected to the working ground GNDS_A.

[0042] Furthermore, one end of the relay K1 control coil is connected to the power supply VCC (+12VDC) and the cathode of the diode VD1, the anode of the diode VD1 is connected to the other end of the relay K1 control coil and the collector of the NPN transistor VT1, the base of the NPN transistor VT1 is connected to one end of the resistor R1, one end of the resistor R2 and one end of the capacitor C1, the other end of the resistor R1 is connected to the control signal K1_DRV of the relay K1, the emitter of the NPN transistor VT1, the other end of the resistor R2 and the other end of the capacitor C1 are connected to the working ground GNDS_D; the working ground GNDS_D and the working ground GNDS_A are respectively the digital ground and the analog ground short-circuited in the main control unit.

[0043] Furthermore, one end of the relay K2 control coil is connected to the power supply VCC (+12VDC) and the cathode of the diode VD3, the anode of the diode VD3 is connected to the other end of the relay K2 control coil and the collector of the NPN transistor VT2, the base of the NPN transistor VT2 is connected to one end of the resistor R19, one end of the resistor R20 and one end of the capacitor C8, the other end of the resistor R19 is connected to the control signal K2_DRV of the relay K2, and the emitter of the NPN transistor VT2, the other end of the resistor R20 and the other end of the capacitor C8 are connected to the working ground GNDS_D.

[0044] Furthermore, the negative output terminal Vout_N of the charger is connected to one end of the resistor R21 and one end of the resistor R18, the other end of the resistor R21 is connected to one end of the capacitor C12 and one end of the resistor R26, the other end of the capacitor C12 is connected to the working ground GNDS_A, the other end of the resistor R26 is connected to one end of the capacitor C9, one end of the resistor R24, one end of the resistor R29 and the fourth pin of the reverse input terminal of the operational amplifier D2, the other end of the capacitor C9, the other end of the resistor R24, one end of the resistor R23 and the first pin of the output terminal of the operational amplifier D2 are connected, the other end of the resistor R29 is connected to the working ground GNDS_A, the other end of the resistor R23, one end of the capacitor C7 and the third pin of the diode VD4 are connected to generate the output current detection signal ISE2_DSC, the other end of the capacitor C7 is connected to the working ground GNDS_A, and the first pin of the diode VD4 is connected to the working ground GND S_A, the second pin of diode VD4 is connected to the working power supply VCC+3.3VA, the other end of resistor R18 and one end of resistor R22 are connected to the working ground GNDS_A, the other end of resistor R22 is connected to one end of capacitor C13 and one end of resistor R27, the other end of capacitor C13 is connected to the working ground GNDS_A, the other end of resistor R27 is connected to one end of capacitor C14, one end of resistor R28, one end of resistor R25 and the same-direction input pin 3 of op amp D2, the other end of capacitor C14, the other end of resistor R28, one end of capacitor C10 and the second pin of op amp D2 are connected to the working ground GNDS_A, the other end of resistor R25 and the other end of capacitor C10 are connected to the working power supply VCC+3.3VA, one end of capacitor C11 is connected to the working power supply +5VDC, and the other end of capacitor C11 is connected to the working ground GNDS_A.

[0045] In addition, the output signal Vout_SE generated by the detection circuit 1, the output signal Vbat_SE generated by the detection circuit 2, and the output signal ISE2_DSC generated by the detection circuit 3 need to be sent to the main control unit circuit of the charger. The main control unit circuit of this embodiment is a digital control circuit composed of a digital signal processor as the core. The digital control circuit judges the positive and negative polarity of the battery voltage Vbat_P. When the battery is reversely connected, the relay K1 is maintained in the disconnected state to achieve anti-reverse connection protection; when the battery is connected normally, this digital control circuit outputs Vout_P and the battery voltage Vbat_P. t_P is used for comparison to control the closing of relay K1; the main control unit circuit calculates the ISE2_DSC signal and compares it with the preset output current value. When the output current is greater than or equal to the preset value, a control instruction to close relay K2 is given. When it is less than the preset current value, relay K2 is kept disconnected. When the output current is detected to be a reverse current, relay K2 is quickly disconnected; this digital control circuit simultaneously controls and realizes the standby mode, output slow start, normal operation and shutdown functions of the charger. The specific judgment, calculation comparison or other control functions of this digital control circuit are not elaborated in detail here.

[0046] The working principle of this embodiment is briefly described as follows:

[0047] After the charger main control unit works normally, the voltage Vbat_P at the battery end is first detected by the differential detection circuit composed of the operational amplifier D1 and the surrounding sampling resistors. When the battery is reversely connected, the voltage Vbat_P is detected to be negative. In this case, the control relay circuit will maintain the disconnected state of the relay K1 to achieve anti-reverse connection protection, so that the reverse connection of the battery will not cause any adverse effect on the reliability of the charger;

[0048] When the battery is connected normally, the voltage Vbat at the battery end is detected to be positive. The main control unit of the charger performs a slow start of the output when it detects that other conditions are normal. When the internal output voltage Vout of the charger rises to about 0.2V lower than the battery voltage Vbat, the main control unit circuit of the charger sends a normally energized high-level signal K1_DRV to the relay K1 control circuit, and the relay K1 is energized, thereby achieving zero-voltage energization of the two contacts of the relay K1, which greatly reduces the current flowing through the contacts of the relay K1 when the relay K1 is energized, avoiding adhesion, damage or damage to the relay due to excessive current, and then the charger charges the battery normally.

[0049] The anti-backflow diode VD2 prevents the battery from backflowing in normal working mode and when the charger output is abnormal.

[0050] The output current, i.e., the current flowing through the sampling resistor R18, is detected by the differential detection circuit composed of the operational amplifier D2 and the sampling resistors around it. When the output current is detected to be greater than or equal to the set value (such as 0.5A), the main control unit circuit gives the drive signal K2_DRV of the relay K2 as a high level, and the relay K2 is energized. At the same time, it is best for the main control unit circuit to set the output current limit point to be slightly greater than 0.5A (such as 1A), so that the two contacts of the normally open relay K2 short-circuit the anti-backflow diode VD2, and the two contacts of the normally open relay K2 are zero voltage energized. At the moment when the normally open relay K2 is energized, there will be no excessive instantaneous charging current, and the anti-backflow diode The current flowing through VD2 is basically zero, and then the main control unit circuit gradually increases the current limit value of the output charging current to the required maximum current limit value; when it is detected that the output current is less than the set value (such as 0.5A), the main control unit circuit gives the drive signal K2_DRV of relay K2 as a low level, and relay K2 remains disconnected; when the output current is detected as a reverse current due to failure of the output rectifier diode or capacitor inside the charger, K2_DRV is quickly given as a low level, and relay K2 is quickly disconnected, so that the anti-reverse diode VD2 is connected in series with the output circuit to effectively prevent the battery current from reversely flowing, which can effectively prevent the spread of the fault in this case.

[0051] In addition, the present invention can detect the internal output terminal voltage and the battery terminal voltage, and can simultaneously detect abnormal conditions such as output overvoltage, undervoltage and short circuit, and send the detection signal to the charger control unit circuit for corresponding protection.

[0052] The above description is only a typical implementation of the present invention. The relay K1 described in the text can be a contactor or a DC relay or an AC relay. The specific positions of the anti-backflow diode and the detection circuit 3 in the circuit are not limited to the positions shown in the scheme in the text. The detection circuit 3 is not limited to using a resistor to sample the output current. A Hall current sensor can also be used for sampling. Figure 3 As shown, the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the principle of the present invention belong to the protection scope of the present invention. For those skilled in the art, several improvements made without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

[0053] The second aspect of the present invention provides a control method for a charger output anti-reverse connection and anti-backflow protection device, which is implemented based on the above-mentioned charger anti-reverse connection and anti-backflow device. The method includes: detecting the voltage polarity of the battery through the detection circuit 2, and when it is detected that the battery is reversely connected, keeping the first relay in the disconnected state to achieve battery reverse connection protection; when the battery is normally connected and the difference between the internal output voltage of the charger and the battery voltage is lower than the set value, controlling the first relay to be energized to start the charging process.

[0054] Preferably, when charging is started, the voltage signal at the output end of the charger is monitored by the detection circuit 1 to ensure that the two contacts are opened with zero voltage when the first relay is energized.

[0055] Preferably, the method further includes: detecting the output current of the charger by means of the detection circuit 3, and when it is detected that the output current is greater than a preset value, controlling the second relay to be energized to short-circuit the anti-backflow diode; when it is detected that the output current is abnormally a backflow current, quickly disconnecting the second relay to avoid damage to the charger and the battery caused by the backflow current.

[0056] Preferably, the closing and opening operations of the second relay are realized by the main control unit circuit, and the main control unit drives and controls the second relay according to the current signal provided by the detection circuit 3.

[0057] Preferably, the main control unit circuit is used to process the signals of each detection circuit and control the closing and opening of the first relay and K2.

[0058] Those skilled in the art will understand that all or part of the steps in the method for implementing the above-mentioned embodiments can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for making a single-chip microcomputer, a chip or a processor (processor) perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0059] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, the technical scheme of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0060] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A protection device for preventing reverse connection and reverse filling of a charger output, characterized in that: The device comprises: Detection circuit 1, detection circuit 2, detection circuit 3, relay control circuit 1, relay control circuit 2, anti-backflow diode, first relay and first diode in reverse connection on its control line package, second relay and second diode in reverse connection on its control line package; wherein, Detection circuit 1 is used to detect the voltage signal at the output end of the charger, detection circuit 2 is used to detect the voltage polarity of the battery end, detection circuit 3 is used to detect the output current signal of the charger, relay control circuit 1 is used to control the attraction and disconnection of the output first relay, and relay control circuit 2 is used to control the attraction and disconnection of the second relay.

2. The protection device according to claim 1, characterized in that: The anode of the anti-backflow diode is connected to the positive output terminal of the charger, and the cathode is connected to a contact of the second relay and a contact of the first relay; The conduction loss of the anti-backflow diode is reduced by controlling the closing and opening of the second relay.

3. The protection device according to claim 1, characterized in that: The negative end of the charger output is connected to one end of the detection circuit 3, which is used to detect the output current and send a signal to the main control unit circuit to monitor the output current and control the closing and opening of the second relay according to the output current signal.

4. The protection device according to claim 1, characterized in that: One end of the control line package of the output first relay is connected to the power supply and the cathode of the first diode, and the other end is connected to the relay control circuit 1; the relay control circuit 1 controls the attraction and disconnection of the first relay according to the battery voltage polarity detection signal.

5. The protection device according to claim 1, characterized in that: One end of the control coil of the second relay is connected to the power supply and the cathode of the second diode, and the other end is connected to the relay control circuit 2; the relay control circuit 2 is used to control the closure of the second relay when it is detected that the output current exceeds the set value.

6. A control method for a protection device for preventing reverse connection and reverse filling of a charger output, characterized in that: The method is implemented based on the control system for preventing reverse connection and reverse charging of a charger according to any one of claims 1 to 5, and the method comprises: The voltage polarity of the battery is detected by the detection circuit 2. When it is detected that the battery is connected reversely, the first relay is kept disconnected to achieve reverse battery protection. When the battery is connected normally and the difference between the internal output voltage of the charger and the battery voltage is lower than the set value, the first relay is controlled to be closed to start the charging process.

7. The control method according to claim 6, characterized in that: When charging is started, the voltage signal at the output end of the charger is monitored by the detection circuit 1 to ensure that the two contacts are opened with zero voltage when the first relay is closed.

8. The control method according to claim 6, characterized in that: The method further comprises: The output current of the charger is detected by the detection circuit 3. When the output current is detected to be greater than a preset value, the second relay is controlled to be closed to short-circuit the anti-backflow diode; When it is detected that the output current is abnormally reverse current, the second relay is quickly disconnected to avoid damage to the charger and the battery caused by the reverse current.

9. The control method according to claim 8, characterized in that: The closing and opening operations of the second relay are realized by the main control unit circuit, and the main control unit drives and controls the second relay according to the current signal provided by the detection circuit 3.

10. The protection device or method according to claim 6, characterized in that: The main control unit circuit is used to process the signals of each detection circuit and control the closing and opening of the first relay and the second relay.

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