An overvoltage protection circuit, an AGV trolley energy braking control device and an AGV trolley

Abstract

This invention relates to the field of intelligent vehicle control, specifically disclosing an overvoltage protection circuit, an AGV (Automated Guided Vehicle) energy braking control device, and an AGV, including a voltage detection circuit, a comparison circuit, a drive circuit, a discharge circuit, and a voltage monitoring circuit. The voltage detection circuit samples and filters the battery voltage, improving the reliability and accuracy of the detection. The comparison circuit compares the filtered sampled signal with a reference voltage to accurately determine whether the battery is overvoltage and outputs a control signal in a timely manner. Upon receiving the control signal, the drive circuit quickly activates the discharge circuit, effectively reducing the battery voltage to within a preset safety threshold, thereby preventing damage to the main circuit electrical components due to overvoltage. Simultaneously, the voltage monitoring circuit collects the battery voltage in real time and transmits it to the control system, achieving real-time monitoring of the battery status.

Description

Technical Field

[0001] This invention relates to the field of intelligent vehicle control, and in particular to an overvoltage protection circuit, an AGV energy braking control device, and an AGV. Background Technology

[0002] An Automated Guided Vehicle (AGV) is a transport vehicle equipped with electromagnetic or optical automatic guidance devices, enabling it to travel along a predetermined guidance path and providing safety protection and various transfer functions. It can automatically transport materials in industrial environments according to preset routes or instructions without a driver.

[0003] Existing AGVs lack effective braking systems in their design, leading to problems such as inaccurate positioning during operation and stopping. Furthermore, main circuit electrical components are frequently damaged by overvoltage, affecting not only equipment performance and lifespan but also increasing maintenance costs and reducing production efficiency. Summary of the Invention

[0004] This invention provides an overvoltage protection circuit, an AGV trolley energy braking control device, and an AGV trolley to prevent damage to the main circuit electrical components due to overvoltage.

[0005] This invention discloses an overvoltage protection circuit, comprising: a voltage detection circuit for converting battery voltage into a sampling signal and filtering out interference signals in the sampling signal;

[0006] The comparison circuit is used to compare the filtered sampled signal with the reference voltage and output a control signal to the drive circuit based on the comparison result.

[0007] The drive circuit turns on and off the discharge circuit based on the control signal.

[0008] The discharge circuit is used to reduce the battery voltage to a preset threshold range;

[0009] A voltage monitoring circuit is used to acquire the sampling signal in real time and input the sampling signal to the control system.

[0010] Furthermore, the voltage detection circuit includes: multiple sampling resistors and an RC filter circuit;

[0011] The battery voltage is divided by multiple sampling resistors to obtain a sampling signal, which is then filtered by an RC filter circuit.

[0012] Furthermore, the voltage detection circuit includes: a current-limiting resistor, a Jonah diode, a filter capacitor, a comparator, a positive feedback resistor, a pull-up resistor, and a base current-limiting resistor;

[0013] The power supply voltage is passed through the current-limiting resistor and the Jonah diode to obtain the reference voltage. The reference voltage is filtered by the filter capacitor and then input to the inverting input of the comparator. The non-inverting input of the comparator is connected to the sampling signal. The output of the comparator is connected to the power supply voltage through the pull-up resistor and to the input of the drive circuit through the base current-limiting resistor.

[0014] The non-inverting input of the comparator is also connected to the output of the comparator through the positive feedback resistor.

[0015] Furthermore, the driving circuit includes: a PNP transistor, a load resistor, a decoupling capacitor, a first pull-down resistor, a push-pull transistor circuit, and a series current-limiting resistor;

[0016] The base of the PNP transistor is connected to the output of the comparator, the collector is connected to the power supply voltage, and the emitter of the PNP transistor is grounded through the decoupling capacitor and the first pull-down resistor.

[0017] In a push-pull transistor circuit, the input terminal is connected to the output terminal of the PNP transistor through the load resistor, and the output terminal of the push-pull transistor circuit outputs an amplified drive current through the series current-limiting resistor.

[0018] Furthermore, the discharge circuit includes: a second pull-down resistor, a diode, an NMOS transistor, and a discharge resistor;

[0019] One end of the second pull-down resistor is connected between the gate of the NMOS transistor and the series current-limiting resistor, and the other end is connected to the source of the NMOS transistor and grounded. The drain of the NMOS transistor is connected to the battery voltage through the diode, and the source is grounded. The discharge resistor is connected in parallel across the diode.

[0020] Furthermore, the voltage monitoring circuit includes a CPU.

[0021] Furthermore, the control system includes a host computer.

[0022] On the other hand, the present invention also discloses an AGV trolley energy braking control device, which adopts the above-mentioned overvoltage protection circuit.

[0023] On the other hand, the present invention also discloses an AGV trolley that uses the above-mentioned trolley energy braking control device.

[0024] Compared with the prior art, the present invention has at least the following technical effects:

[0025] The battery voltage is sampled and filtered by a voltage detection circuit, improving the reliability and accuracy of the detection. The comparison circuit compares the filtered sampled signal with a reference voltage to accurately determine if the battery is overvoltage and promptly outputs a control signal. Upon receiving the control signal, the drive circuit quickly activates the discharge circuit, effectively reducing the battery voltage to within a preset safety threshold, thus preventing damage to main circuit electrical components due to overvoltage. Simultaneously, the voltage monitoring circuit acquires the battery voltage in real time and transmits it to the control system, enabling real-time monitoring of the battery status.

[0026] Furthermore, the overvoltage protection circuit was applied to the AGV, which solved the problem of component damage caused by overvoltage in the main circuit of the AGV. Through real-time voltage monitoring and dynamic discharge control, the stability of equipment operation and positioning accuracy were improved, maintenance costs and downtime risks were reduced, and the problems of overvoltage damage and inaccurate braking in the existing technology were effectively solved. Attached Figure Description

[0027] Figure 1 This is a simplified flowchart of an overvoltage protection circuit in one embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the overvoltage protection circuit in one embodiment of the present invention. Detailed Implementation

[0029] The following description, with reference to schematic diagrams, illustrates an overvoltage protection circuit, an AGV energy braking control device, and an AGV, according to the present invention. Preferred embodiments of the invention are shown. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0030] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0031] Example 1

[0032] Please refer to Figure 1 This embodiment discloses an overvoltage protection circuit, including:

[0033] A voltage detection circuit is used to convert the battery voltage Vbat into a sampling signal and filter out interference signals in the sampling signal; a comparison circuit is used to compare the filtered sampling signal with a reference voltage and output a control signal to the drive circuit based on the comparison result; the drive circuit turns on the discharge circuit based on the control signal; the discharge circuit is used to reduce the battery voltage Vbat to a preset threshold range; and a voltage monitoring circuit is used to acquire the sampling signal in real time and input the sampling signal to the control system.

[0034] In this embodiment, the battery voltage Vbat is sampled and filtered by a voltage detection circuit, improving the reliability and accuracy of the detection. The comparison circuit compares the filtered sampled signal with a reference voltage to accurately determine whether the battery is over-voltage and outputs a control signal in a timely manner. After receiving the control signal, the drive circuit quickly turns on the discharge circuit, effectively reducing the battery voltage Vbat to within a preset safety threshold, thereby avoiding damage to the main circuit electrical components due to overvoltage.

[0035] Furthermore, the voltage detection circuit includes: multiple sampling resistors and an RC filter circuit.

[0036] Specifically, the battery voltage Vbat is divided by multiple sampling resistors to obtain a sampling signal, and the sampling signal is filtered by an RC filter circuit.

[0037] In one specific embodiment, please refer to Figure 2 It includes a first sampling resistor R1, a second sampling resistor R2, a third sampling resistor R3, and a fourth sampling resistor R4. The battery voltage Vbat is obtained by sequentially dividing the voltage through the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3, and the fourth sampling resistor R4 to obtain the sampling signal.

[0038] It is understood that the number of sampling resistors depends on the actual situation and is not specifically limited here.

[0039] Furthermore, the voltage detection circuit includes: a current-limiting resistor R8, a Jonah diode Z1, a filter capacitor C3, a comparator U1A, a positive feedback resistor R6, a pull-up resistor R7, and a base current-limiting resistor R10.

[0040] The power supply voltage is used to obtain a reference voltage after passing through the current-limiting resistor R8 and the Jonah diode Z1. The reference voltage is filtered by the filter capacitor and then input to the inverting input of comparator U1A. The non-inverting input of comparator U1A is connected to the sampling signal. The output of comparator U1A is connected to the power supply voltage through the pull-up resistor R7 and to the input of the drive circuit through the base current-limiting resistor R10. The non-inverting input of comparator U1A is also connected to the output of comparator U1A through the positive feedback resistor R6.

[0041] In one specific embodiment, the power supply voltage is +12V. Of course, those skilled in the art can choose different power supply voltages according to actual conditions.

[0042] The voltage detection circuit described above operates as follows: the power supply voltage is limited by the current-limiting resistor R8 and then input to the Jonas diode Z1, utilizing its reverse breakdown characteristic to generate a stable reference voltage. The reference voltage, after being filtered by the filter capacitor C3 to remove high-frequency noise, is input to the inverting input of comparator U1A, while the sampling signal is simultaneously input to the non-inverting input of comparator U1A. Under normal conditions, when the sampling voltage is lower than the reference voltage, the comparator output is pulled high by the pull-up resistor R7, and the subsequent drive circuit remains off. If the battery experiences overvoltage, causing the sampling voltage to exceed the reference voltage, the comparator output immediately flips to a low level. This low-level signal triggers the subsequent drive circuit to conduct through the base current-limiting resistor R10.

[0043] Furthermore, the driving circuit includes: a PNP transistor Q1, a load resistor R12, a decoupling capacitor C4, a first pull-down resistor R11, a push-pull transistor circuit (consisting of Q2 and Q3 in the figure) and a series current-limiting resistor R13.

[0044] Specifically, the base of the PNP transistor Q1 is connected to the output of the comparator U1A, the collector is connected to the power supply voltage, and the emitter of the PNP transistor Q1 is grounded through the decoupling capacitor C4 and the first pull-down resistor R11.

[0045] The push-pull transistor circuit has its input terminal connected to the output terminal of the PNP transistor Q1 through the load resistor R12, and its output terminal outputs an amplified drive current through the series current-limiting resistor R13.

[0046] Specifically, when the comparator outputs a high-level signal, the base-emitter voltage of the PNP transistor Q1 decreases, causing its conduction state to change. At this time, the input terminal of the push-pull transistor circuit receives the current signal from the PNP transistor Q1 through the load resistor. After amplification by the complementary transistor, a current with sufficient driving capability is formed at the output terminal. This current acts on the discharge circuit through the series current-limiting resistor R13, ensuring the strength of the driving signal while preventing damage to the device due to excessive current.

[0047] Through the above technical solution, this application can significantly improve the stability and response speed of the drive signal, enabling the discharge circuit to start in time when the battery is over-voltage. The symmetrical drive characteristics of the push-pull structure can eliminate the signal delay present in traditional single-transistor drives, while the setting of the current-limiting resistor enhances the safety margin of the circuit and avoids device damage caused by sudden current changes during the drive process.

[0048] Furthermore, the discharge circuit includes: a second pull-down resistor R14, a diode D5, an NMOS transistor Q4, and a discharge resistor R15.

[0049] Specifically, one end of the second pull-down resistor R14 is connected between the gate of the NMOS transistor Q4 and the series current-limiting resistor R13. The source of the NMOS transistor Q4 is grounded, and the drain of the NMOS transistor Q4 is connected to the battery voltage Vbat through the diode D5. The discharge resistor R15 is connected in parallel across the diode D5.

[0050] Specifically, when the drive circuit outputs a control signal, the gate of NMOS transistor Q4 receives a drive voltage and turns on. At this time, the battery voltage Vbat forms a discharge circuit through the diode and NMOS transistor Q4. The discharge resistor R15 and diode D5 are connected in parallel to form a discharge path, thereby reducing the bus voltage to a controllable threshold range and preventing damage to electrical components. Since the discharge resistor R15 is directly connected across diode D5, a discharge path can be quickly established when NMOS transistor Q4 is turned on. Simultaneously, diode D5 can block the reverse current from impacting the battery. Furthermore, the pull-down resistor R14 pulls the gate potential down to ground, allowing NMOS transistor Q4 to be reliably turned off when there is no drive signal.

[0051] Through the above technical solutions, this embodiment can quickly establish a low-impedance discharge path when overvoltage is detected, effectively suppressing voltage spikes. The combined use of pull-down resistor R14 and NMOS transistor Q4 ensures reliable switching of the switching state, and the introduction of diode D5 prevents reverse current from damaging the battery. The parallel arrangement of discharge resistor R15 achieves uniform current distribution and extends the service life of components.

[0052] Furthermore, the voltage monitoring circuit includes a CPU (Central Processing Unit) for real-time acquisition of the battery voltage Vbat and synchronous transmission of the acquired voltage signal to the control system for real-time monitoring of the battery voltage Vbat status. Of course, those skilled in the art can select different processors according to actual needs, and no specific limitations are made here.

[0053] Furthermore, the control system includes a host computer. Its main purpose is to monitor the battery voltage (Vbat) status in real time. Through the host computer interface, the system can intuitively display the current battery voltage data, record and analyze the data, so that operators or automated programs can continuously monitor the battery's health status and operating trends, and promptly issue warnings or handle abnormal situations, thereby effectively improving battery management and the overall operational reliability of the AGV intelligent vehicle.

[0054] This embodiment further discloses an AGV (Automated Guided Vehicle) energy braking control device, including the overvoltage protection circuit described above.

[0055] When the AGV's battery voltage Vbat rises due to energy feedback during braking, the voltage detection circuit converts Vbat into a sampling signal and filters out interference. The comparison circuit compares the filtered sampling signal with a reference voltage. When overvoltage is detected, a control signal is output to the drive circuit. The drive circuit amplifies the drive current through a push-pull transistor, triggering the discharge circuit to reduce the battery voltage Vbat to a safe threshold. The voltage monitoring circuit collects the battery voltage Vbat data in real time and transmits it to the control system, forming a closed-loop control. Thus, the overvoltage protection circuit is integrated into the AGV's energy braking control device, solving the problem of component damage caused by overvoltage in the main circuit. Through real-time voltage monitoring and dynamic discharge control, the stability and positioning accuracy of the equipment are improved, while maintenance costs and downtime risks are reduced.

[0056] This embodiment further discloses an AGV trolley, including the above-mentioned AGV trolley energy braking control device.

[0057] The above-described modifications and variations do not depart from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the invention and their equivalents, the invention also intends to include these modifications and variations.

Claims

1. An overvoltage protection circuit, characterized by, include: A voltage detection circuit is used to convert the battery voltage into a sampling signal and filter out interference signals in the sampling signal; The comparison circuit is used to compare the filtered sampled signal with the reference voltage and output a control signal to the drive circuit based on the comparison result. The drive circuit turns on and off the discharge circuit based on the control signal. The discharge circuit is used to reduce the battery voltage to a preset threshold range; A voltage monitoring circuit is used to acquire the sampling signal in real time and input the sampling signal to the control system.

2. The overvoltage protection circuit of claim 1, wherein, The voltage detection circuit includes: multiple sampling resistors and an RC filter circuit; The battery voltage is divided by multiple sampling resistors to obtain a sampling signal, which is then filtered by an RC filter circuit.

3. The overvoltage protection circuit of claim 2, wherein, The voltage detection circuit includes: a current-limiting resistor, a Jonah diode, a filter capacitor, a comparator, a positive feedback resistor, a pull-up resistor, and a base current-limiting resistor; The power supply voltage is passed through the current-limiting resistor and the Jonah diode to obtain the reference voltage. The reference voltage is filtered by the filter capacitor and then input to the inverting input of the comparator. The non-inverting input of the comparator is connected to the sampling signal. The output of the comparator is connected to the power supply voltage through the pull-up resistor and to the input of the drive circuit through the base current-limiting resistor. The non-inverting input of the comparator is also connected to the output of the comparator through the positive feedback resistor.

4. The overvoltage protection circuit of claim 3, wherein, The driving circuit includes: a PNP transistor, a load resistor, a decoupling capacitor, a first pull-down resistor, a push-pull transistor circuit, and a series current-limiting resistor; The base of the PNP transistor is connected to the output of the comparator, the collector is connected to the power supply voltage, and the emitter of the PNP transistor is grounded through the decoupling capacitor and the first pull-down resistor. In a push-pull transistor circuit, the input terminal is connected to the output terminal of the PNP transistor through the load resistor, and the output terminal of the push-pull transistor circuit outputs an amplified drive current through the series current-limiting resistor.

5. The overvoltage protection circuit of claim 4, wherein, The discharge circuit includes: a second pull-down resistor, a diode, an NMOS transistor, and a discharge resistor; One end of the second pull-down resistor is connected between the gate of the NMOS transistor and the series current-limiting resistor, and the other end is connected to the source of the NMOS transistor and grounded. The drain of the NMOS transistor is connected to the battery voltage through the diode, and the source is grounded. The discharge resistor is connected in parallel across the diode.

6. The overvoltage protection circuit of claim 1, wherein, The voltage monitoring circuit includes a CPU.

7. The overvoltage protection circuit of claim 1, wherein, The control system includes a host computer.

8. An AGV trolley energy brake control device, characterized in that, The overvoltage protection circuit described in any one of claims 1-7 is adopted.

9. An AGV cart, characterized by The vehicle energy braking control device as described in claim 8 is adopted.

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