Adjustable tractor main cable current protection system and tractor

Abstract

The present invention discloses an adjustable tractor main cable current protection system and a tractor. The system includes: a Hall current detection circuit for detecting the tractor main cable current and converting the current signal into a voltage signal. The Hall current detection circuit is connected to the first input of an AND gate circuit via a comparator, a regulation circuit, and an inversion circuit. A power switch circuit is connected to the second input of the AND gate circuit. The output of the AND gate circuit is connected to the first input of an OR gate and protection circuit. A start signal input circuit is connected to the second input of the OR gate and protection circuit. The output of the OR gate and protection circuit is connected to a main switch, and the output of the OR gate and protection circuit is connected to the second input of the AND gate circuit via a feedback circuit. The present invention can effectively implement current protection for the tractor main cable, with fewer components and low cost. It is constructed using analog and digital chips, resulting in high reliability. The switch controls power on and off, making operation simple and convenient. The protection current is adjustable and has good compatibility.

Description

Technical Field

[0001] The present invention relates to the technical field of tractors, and in particular to an adjustable tractor main cable current protection system and a tractor. Background Art

[0002] The tractor's main cable, also known as the starting cable, connects the battery's positive terminal to the starter's power supply after passing through the main power relay. During starting, the current is approximately 800A to 1000A. Tractor main cables lack overcurrent protection. A short circuit in this cable could cause a fire or even a battery explosion, resulting in significant damage to the user's property and personal safety. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an adjustable tractor main cable current protection system and a tractor in response to the problems existing in the prior art.

[0004] To solve the above technical problems, the present invention provides an adjustable tractor main cable current protection system, comprising: a Hall current detection circuit for detecting the tractor main cable current and converting the current signal into a voltage signal, a comparator and a regulation circuit, an inversion circuit, an AND gate circuit, an OR gate and a protection circuit, a main switch, a power switch circuit, a feedback circuit, and a start signal input circuit;

[0005] The Hall current detection circuit, the comparator and the regulation circuit and the inversion circuit are connected in sequence and connected to the first input end of the AND gate circuit, the power switch circuit is connected to the second input end of the AND gate circuit, the output end of the AND gate circuit is connected to the first input end of the OR gate and protection circuit, the start signal input circuit is connected to the second input end of the OR gate and protection circuit, the output end of the OR gate and protection circuit is connected to the main switch, and the output end of the OR gate and protection circuit is connected to the second input end of the AND gate circuit through the feedback circuit.

[0006] The present invention has the following beneficial effects: it can disconnect the main power supply when the main cable current is too high, thereby protecting the battery and cables. It can also perform current detection and shielding during the vehicle startup phase, thereby preventing the main switch from shutting off due to false detection. The present invention uses fewer components and is low-cost; it is constructed using analog and digital chips, resulting in high reliability; the switch controls power on and off, making operation simple and convenient; and the protection current is adjustable, ensuring good compatibility.

[0007] On the basis of the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, the Hall current detection circuit includes: a Hall current transformer.

[0009] The beneficial effect of adopting the above further solution is that the tractor main cable current is detected by the Hall current transformer, the main cable current signal is converted into a voltage signal, and real-time detection of the main cable current signal is achieved.

[0010] Furthermore, the comparator and adjustment circuit includes an operational amplifier, a first resistor and a second resistor; the second resistor is an adjustable resistor; the Hall current detection circuit is connected to the positive input terminal of the operational amplifier; one end of the first resistor is connected to the tractor main cable, and the other end is connected to the negative input terminal of the operational amplifier; one end of the second resistor is grounded, and the other end is connected to the negative input terminal of the operational amplifier; the output terminal of the operational amplifier is connected to the inversion circuit.

[0011] The beneficial effect of adopting the above further scheme is that a comparator is built using an operational amplifier, and the voltage value at the negative input terminal of the operational amplifier can be changed by adjusting the resistance value of the second resistor, which is compared with the voltage value output by the Hall current detection circuit, and a high level is output when the current in the tractor main cable is abnormal, so that the subsequent circuit can perform power-off control according to the low level; the resistance value of the second resistor is adjustable, so the current protection value of the tractor main cable can be adjusted.

[0012] Furthermore, the negation circuit includes: a NOT gate element; and the AND gate circuit includes: an AND gate element.

[0013] Furthermore, the OR gate and protection circuit include an OR gate element and a diode; the output end of the AND gate circuit is connected to the first input end of the OR gate element, the start signal input circuit is connected to the second input end of the OR gate element, the output end of the OR gate element is connected to the positive electrode of the diode, the negative electrode of the diode is connected to the main switch, and the negative electrode of the diode is connected to the second input end of the AND gate circuit through the feedback circuit.

[0014] The beneficial effect of adopting the above further solution is that the OR gate and protection circuit perform an OR operation on the logic signal output by the AND gate circuit and the logic level of the start signal output by the start signal input circuit, and use the diode to limit the current direction to protect the OR gate chip.

[0015] Furthermore, the main switch is an electromagnetic switch.

[0016] Furthermore, the power switch circuit adopts a self-resetting rocker switch, or adopts two independent touch self-resetting switches.

[0017] Furthermore, the feedback circuit includes a third resistor.

[0018] The beneficial effect of adopting the above further solution is that the level logic signal of the main switch output terminal is fed back through the feedback circuit, thereby forming an interlock with the level logic signal of the power switch circuit output terminal.

[0019] Furthermore, the start signal input circuit includes: a tractor start switch and a fourth resistor; one end of the tractor start switch is connected to the main switch, and the other end is connected to the OR gate and the second input end of the protection circuit; one end of the fourth resistor is connected to the OR gate and the second input end of the protection circuit, and the other end is grounded.

[0020] The beneficial effect of adopting the above further solution is that, by adding a start signal input circuit, current detection shielding is achieved during the vehicle startup phase, thereby avoiding false detection leading to power failure of the main switch.

[0021] In order to solve the above technical problems, the present invention also provides a tractor, comprising the adjustable tractor main cable current protection system described in the above technical solution.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A block diagram of an adjustable tractor main cable current protection system provided by an embodiment of the present invention;

[0024] Figure 2 A schematic circuit diagram of an adjustable tractor main cable current protection system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present disclosure through specific concrete examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0026] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0027] Figure 1 This is a block diagram of an adjustable tractor main cable current protection system provided by an embodiment of the present invention. Figure 1 As shown, the system includes: a Hall current detection circuit 100 for detecting the current of the tractor main cable and converting the current signal into a voltage signal, a comparator and regulation circuit 200, an inversion circuit 300, an AND gate circuit 400, an OR gate and protection circuit 500, a main switch 600, a power switch circuit 700, a feedback circuit 800 and a start signal input circuit 900.

[0028] The Hall current detection circuit 100, the comparator and regulation circuit 200 and the inversion circuit 300 are connected in sequence and connected to the first input end of the AND gate circuit 400, the power switch circuit 700 is connected to the second input end of the AND gate circuit 400, the output end of the AND gate circuit 400 is connected to the first input end of the OR gate and protection circuit 500, the start signal input circuit 900 is connected to the second input end of the OR gate and protection circuit 500, the output end of the OR gate and protection circuit 500 is connected to the main switch 600, and the output end of the OR gate and protection circuit 600 is connected to the second input end of the AND gate circuit 400 through the feedback circuit 800.

[0029] In an embodiment of the present invention, a Hall current detection circuit detects the current of the tractor main cable in real time, and converts the current signal into a voltage signal which is input into a comparator and a regulation circuit. If the main cable current is abnormal, the comparator and the regulation circuit output a high level, which is inverted to a low level by the inversion circuit, and then outputs a low level through the AND gate circuit. If both input ends of the OR gate and the protection circuit are low, the output is low, causing the main switch to be disconnected; and the second input end of the AND gate circuit is made low through the feedback circuit, so that the main switch remains in the disconnected state and will not be re-engaged even if the main cable current returns to normal. It can only be re-engaged through human intervention.

[0030] Furthermore, this embodiment of the present invention incorporates a start signal into the OR gate. When the vehicle is started, the start signal is high, and when the start button is released, the start signal is in a high-impedance state. During vehicle startup, the second input of the OR gate and the protection circuit remain high, ensuring that the OR gate output is always high and the main switch remains closed. This enables current detection shielding during the vehicle startup phase, preventing the main switch from shutting off due to false detection.

[0031] This embodiment of the present invention disconnects the main power supply when the main cable current is too high, thereby protecting the battery and cables. It also performs current detection shielding during vehicle startup to prevent main switch power outages due to false detections. Furthermore, a comparator and regulation circuit can adjust the reference voltage, enabling adjustable main cable current protection values. This invention utilizes fewer components, resulting in low cost. Its analog-to-digital chip architecture offers high reliability. Switch-controlled power-on and power-off ensures simple and convenient operation. The protection current is adjustable, ensuring good compatibility.

[0032] The following is a detailed description of each circuit:

[0033] The Hall current detection circuit 100 includes a Hall current transformer (CCT) installed on the tractor's main cable. This transformer detects the current in the tractor's main cable and converts the current signal into a voltage output. The tractor's main cable, also known as the starting cable, connects the positive terminal of the battery through the main switch 600 (i.e., the main power relay, an electromagnetic switch with a relay structure that allows a current of 1200A) and then to the vehicle's loads (including the starter and other electrical equipment). The battery provides starting power to the starter, with an output current range of 800A-1000A. The Hall current transformer, model FXBY35, has a current range of 0-1000A and a voltage output of 0-5V.

[0034] The comparator and adjustment circuit 200 includes an operational amplifier, a first resistor, and a second resistor; the second resistor is an adjustable resistor; the Hall current detection circuit 100 is connected to the positive input of the operational amplifier; one end of the first resistor is connected to the tractor main cable, and the other end is connected to the negative input of the operational amplifier; one end of the second resistor is grounded, and the other end is connected to the negative input of the operational amplifier; the output of the operational amplifier is connected to the inversion circuit 300.

[0035] The operational amplifier can be a high-precision operational amplifier of model OP07CDR, which forms a comparator with the first resistor and the second resistor, and the comparison voltage can be adjusted by the second resistor, that is, the current protection value can be adjusted by adjusting the resistance value of the second resistor.

[0036] The embodiment of the present invention uses an operational amplifier to build a comparator, and can change the voltage value of the negative input terminal of the operational amplifier by adjusting the resistance value of the second resistor R2, and compare it with the voltage value output by the Hall current detection circuit 100. When the current in the tractor main cable is abnormal, a high level is output, which facilitates the subsequent circuit to perform power-off control according to the low level.

[0037] The voltage inversion circuit 300 includes a NOT gate element. A Schmitt-trigger NOT gate chip, such as the 74HC14, can be used for voltage inversion. The voltage inversion circuit 300 inverts the logic level output by the comparator and regulation circuit 200, outputting a low level when the tractor's main cable current is abnormal.

[0038] The AND gate circuit 400 includes an AND gate element, which may be a 74LS08 AND gate chip, for implementing a logical AND operation of logic signals at two input terminals.

[0039] The OR gate and protection circuit 500 includes an OR gate element and a diode; the output end of the AND gate circuit 400 is connected to the first input end of the OR gate element, the start signal input circuit 900 is connected to the second input end of the OR gate element, the output end of the OR gate element is connected to the anode of the diode, the cathode of the diode is connected to the main switch 600, and the cathode of the diode is connected to the second input end of the AND gate circuit 400 through the feedback circuit 800.

[0040] The OR gate element can use a 74LS32 OR gate chip to implement a logical OR function. The diode can use an IN4148 diode to protect the OR gate output from short circuits and burnout due to logic highs and lows.

[0041] In the embodiment of the present invention, the OR gate and protection circuit 500 performs an OR operation on the logic signal output by the AND gate circuit 400 and the logic level of the start signal output by the start signal input circuit 900, and uses a diode to limit the current direction, thereby protecting the OR gate chip.

[0042] The main switch 600 is an electromagnetic switch, i.e., a main power relay. It is an electromagnetic switch at the main cable end and uses a relay structure. It allows 1200A of current to flow, thus controlling a large current with a small current.

[0043] The power switch circuit 700 uses a self-resetting rocker switch or two independent trigger-activated self-resetting switches. The power switch circuit 700 is the driver's power switch used to manually turn the power of the vehicle on or off, hereinafter referred to as the control switch.

[0044] Feedback circuit 800 includes a third resistor. This third resistor is a current-limiting resistor. When the power switch is switched to the off position, the cathode of the diode is at a high level, causing a momentary short circuit and potentially damaging the chip. By adding a current-limiting resistor, the present embodiment prevents chip damage caused by switching the power switch to the off position.

[0045] In the embodiment of the present invention, the feedback circuit 800 is used to feed back the level logic signal of the output end of the main switch 600 , thereby forming an interlock with the level logic signal of the output end of the power switch circuit 700 .

[0046] The start signal input circuit 900 includes a tractor start switch and a fourth resistor. One end of the tractor start switch is connected to the main switch 600, and the other end is connected to the OR gate and the second input of the protection circuit 500. One end of the fourth resistor is connected to the OR gate and the second input of the protection circuit 500, and the other end is grounded. The output of the tractor start switch is high when the tractor is started, and high impedance when the tractor is not started. The fourth resistor is used to pull the start signal line down to a low level when the tractor is not started.

[0047] High current flow during tractor startup is normal, and this high current output needs to be shielded within the current protection system. This embodiment of the present invention introduces a start signal into the OR gate. When the vehicle is starting, the start signal is high; when the start button is released, the start signal is high-impedance. During startup, the second input of the OR gate remains high, ensuring that the OR gate output is always high and the electromagnetic switch remains closed. This enables current detection shielding during the vehicle startup phase, preventing the main switch from shutting off due to false detections.

[0048] The following are specific embodiments of the present invention:

[0049] The embodiment of the present invention adopts Figure 2 The adjustable tractor main cable current protection system shown includes a Hall current transformer, an operational amplifier, a first resistor R1, a second resistor R2 (an adjustable resistor), a NOT gate, an AND gate, an OR gate, a diode, a third resistor, a power switch (self-resetting), a main switch, a tractor start switch (self-resetting), and a fourth resistor R4.

[0050] The negative terminal of the battery is grounded, while the positive terminal is connected to one end of the vehicle load via the main switch. The other end of the vehicle load is grounded. A Hall effect current transformer is installed on the tractor main cable between the positive terminal of the battery and the main switch. The Hall effect current transformer is connected to the positive terminal of the operational amplifier. A first resistor R1 has one end connected to the tractor main cable between the positive terminal of the battery and the Hall effect current transformer, and the other end connected to the negative terminal of the operational amplifier. A second resistor R2 has one end grounded and the other end connected to the negative terminal of the operational amplifier. The output of the operational amplifier is connected to the input of a NOT gate, which is connected to the first input of an AND gate. The power switch is connected to the second input of the AND gate, and the output of the AND gate is connected to the first input of an OR gate. One end of the tractor start switch is connected to the main switch, and the other end is connected to the second input of the OR gate. A fourth resistor R4 has one end grounded and the other end connected to the second input of the OR gate. The output of the OR gate is connected to the anode of a diode, the cathode of the diode is connected to the main switch, and is connected to the second input of the AND gate via a third resistor R3.

[0051] The working principle of the adjustable tractor main cable current protection system provided by the embodiment of the present invention is as follows:

[0052] 1. The system power supply is independently drawn from the battery and is not affected by the electromagnetic switch.

[0053] 2. Power-on operation: After the system is built, the control switch (i.e., the power switch circuit) is turned to the power-on position. At this time, the second input of the AND gate is at a high level. Since the current at the first input is at a reasonable position, the comparator outputs a low level, which is converted to a high level through the NOT gate. The AND gate output outputs a high level. The high level serves as the input signal of the OR gate, so the OR gate output is also a high level, and then the diode outputs a high level, which eventually causes the electromagnetic switch (i.e., the main switch) to be energized and closed.

[0054] 3. Release the control switch and the switch contacts reset to the middle position. At this time, the second input terminal of the AND gate still maintains a high level state through the third resistor R3, so the electromagnetic switch remains in the attracted state.

[0055] 4. Starting State: When the tractor is starting, the main cable current is high, which is normal. This high current output needs to be shielded in the current protection system. Therefore, a starting signal is introduced into the OR gate. The starting signal is high during starting and high-impedance when the starter is released. During starting, the second input of the OR gate remains high, so the OR gate output must be high, and the electromagnetic switch remains closed.

[0056] 5. Overcurrent protection: When in normal working state, the positive input terminal of the operational amplifier will collect the output voltage of the Hall transformer and compare it with the negative input terminal; if the main cable current is abnormal, the voltage at the positive input terminal of the operational amplifier will be higher than the voltage at the negative input terminal, and the operational amplifier will output a high level, which will be inverted to a low level through the NOT gate, and then output a low level through the AND gate. If both input terminals of the OR gate are low, the output will be low, causing the electromagnetic switch to be disconnected; and the second input terminal of the AND gate will be low through the feedback circuit, so that the electromagnetic switch will remain in the disconnected state and will not be re-engaged even if the main cable current returns to normal. It can only be re-engaged through human intervention.

[0057] 6. Adjust the current protection value: The first resistor R1 and the second resistor R2 form a voltage divider. By adjusting the resistance value of the second resistor R2 to change the voltage value of the negative input terminal of the operational amplifier, the various values ​​of the second resistor R2 can be converted into protection current indications, clarifying the protection current at each position and facilitating visual adjustment.

[0058] 7. Power-off operation: When the control switch is turned to the power-off position, the second input terminal of the AND gate is at a low level, the output terminal of the AND gate is at a low level, and the output terminal of the OR gate is at a low level, causing the electromagnetic switch to be disconnected; and the second input terminal of the AND gate is at a low level, so that the electromagnetic switch remains in the disconnected state and will not be re-engaged due to the restoration of normal current. It can only be re-engaged through human intervention.

[0059] An embodiment of the present invention further provides a tractor, comprising the adjustable tractor main cable current protection system provided by the above embodiment.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An adjustable tractor main cable current protection system, characterized in that: include: A Hall current detection circuit for detecting the current of the tractor main cable and converting the current signal into a voltage signal, a comparator and a regulation circuit, an inversion circuit, an AND gate circuit, an OR gate and a protection circuit, a main switch, a power switch circuit, a feedback circuit, and a start signal input circuit; The Hall current detection circuit is connected to the input end of the comparator and the regulation circuit, the output end of the comparator and the regulation circuit is connected to the input end of the inversion circuit, the output end of the inversion circuit is connected to the first input end of the AND gate circuit, the power switch circuit is connected to the second input end of the AND gate circuit, the output end of the AND gate circuit is connected to the first input end of the OR gate and the protection circuit, the start signal input circuit is connected to the second input end of the OR gate and the protection circuit, the output end of the OR gate and the protection circuit is connected to the main switch, and the output end of the OR gate and the protection circuit is connected to the second input end of the AND gate circuit through the feedback circuit; The comparator and adjustment circuit includes an operational amplifier, a first resistor and a second resistor; the second resistor is an adjustable resistor; The Hall current detection circuit is connected to the positive input terminal of the operational amplifier; one end of the first resistor is connected to the tractor main cable between the positive electrode of the battery and the Hall current transformer, and the other end is connected to the negative input terminal of the operational amplifier; one end of the second resistor is connected to the negative electrode of the battery, and the other end is connected to the negative input terminal of the operational amplifier; the output terminal of the operational amplifier is connected to the inverting circuit; The operational amplifier, the first resistor and the second resistor form a comparator, and the current protection value is adjusted by adjusting the resistance value of the second resistor.

2. The adjustable tractor main cable current protection system according to claim 1, characterized in that: The Hall current detection circuit includes: a Hall current transformer.

3. The adjustable tractor main cable current protection system according to claim 1, characterized in that: The negation circuit includes: a NOT gate element; the AND gate circuit includes: an AND gate element.

4. The adjustable tractor main cable current protection system according to any one of claims 1 to 3, characterized in that: The OR gate and protection circuit include an OR gate element and a diode; The output end of the AND gate circuit is connected to the first input end of the OR gate element, the start signal input circuit is connected to the second input end of the OR gate element, the output end of the OR gate element is connected to the anode of the diode, the cathode of the diode is connected to the main switch, and the cathode of the diode is connected to the second input end of the AND gate circuit through the feedback circuit.

5. The adjustable tractor main cable current protection system according to any one of claims 1 to 3, characterized in that: The main switch adopts an electromagnetic switch.

6. The adjustable tractor main cable current protection system according to any one of claims 1 to 3, characterized in that: The power switch circuit adopts a self-resetting rocker switch, or adopts two independent touch self-resetting switches.

7. The adjustable tractor main cable current protection system according to any one of claims 1 to 3, characterized in that: The feedback circuit includes a third resistor.

8. The adjustable tractor main cable current protection system according to any one of claims 1 to 3, characterized in that: The start signal input circuit includes: a tractor start switch and a fourth resistor; one end of the tractor start switch is connected to the main switch, and the other end is connected to the OR gate and the second input end of the protection circuit; one end of the fourth resistor is connected to the OR gate and the second input end of the protection circuit, and the other end is grounded.

9. A tractor, characterized in that: The invention comprises the adjustable tractor main cable current protection system according to any one of claims 1 to 8.

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