An energy consumption brake unit

Abstract

The application discloses an energy consumption brake unit, and solves the problems of response delay of existing technology protection, single-point failure risk caused by dependence on a main controller and the like, through the energy consumption brake unit connected between the positive and negative poles of a direct current bus, the unit comprising: a power supply module, a voltage sampling circuit, a voltage monitoring comparator U1, at least one fault protection comparator, a driving chip and a power switch tube. The voltage monitoring comparator U1 outputs a brake enable signal according to the comparison result of the bus voltage sampling and a first reference voltage. The at least one fault protection comparator is used for outputting a protection off signal when a specific fault state reaches a protection threshold. The output ends of the comparators are coupled to the input end of the driving chip through lines and a logic circuit, so that the protection off signal output by any comparator can immediately control the driving chip to turn off the power switch tube, thereby realizing hardware-level fast cooperative protection.

Description

Technical Field

[0001] This application relates to the field of braking control circuit technology, and in particular to an energy-saving braking unit. Background Technology

[0002] In industrial servo drives, frequency converters, and various power electronic systems, the energy-saving braking unit is a critical safety and energy management component. Its basic function is to connect the braking resistor into the circuit by turning on the power switch when the DC bus voltage is too high, so as to consume the excess energy generated by the motor feedback or the system and maintain the stability of the bus voltage.

[0003] The inventors recognized that current common energy-saving braking solutions mainly revolve around the triggering and control methods of the braking function, but still have several limitations that have not been properly resolved for a long time:

[0004] 1. The dependency and delay issues of protection mechanisms.

[0005] Most energy-efficient braking solutions, whether discrete simple circuits or modules integrated within the driver, have inherent flaws in their protection implementation paths (such as abnormal shutdown). Simple solutions often lack effective protection mechanisms. In more complex integrated solutions, overvoltage and overtemperature protection logic typically relies on the software program of the main controller (MCU) for monitoring and judgment. The response speed of this software-dependent protection is limited by the program's scan cycle or interrupt handling delay. In extreme faults such as power stage shoot-through or drastic load changes, it cannot execute shutdown within milliseconds or even microseconds, potentially leading to fault amplification and damage to power devices or braking resistors.

[0006] 2. Risks of system-level failures and single points of failure.

[0007] When the braking function is deeply integrated into the main drive, its operation is tightly bound to the main controller. If the main controller fails due to program crashes, hardware malfunctions, or external interference, the associated braking and protection functions will also be lost. This "single point of failure" architecture reduces the overall safety margin of the system. Furthermore, some external synchronization schemes designed to enable multiple braking units to work collaboratively (e.g., sending trigger signals from a designated master unit to slave units) solve the problem of action consistency, but they do not change the fact that the internal protection capabilities of each unit are weak, and the transfer of control from the slave unit to the outside does not enhance its own safety. Summary of the Invention

[0008] This application provides an energy-efficient braking unit, which aims to solve the problems existing in the prior art, such as the response delay caused by the protection mechanism relying on software, the risk of single point of failure due to the deep binding of the braking function with the main controller, and the difficulty of fault diagnosis and maintenance caused by the lack of independent status indication of the braking unit itself.

[0009] In a first aspect, an energy-saving braking unit is provided, connected between the positive and negative terminals of a DC bus, comprising:

[0010] The power module is used to convert the voltage of the DC bus into a stable internal operating voltage;

[0011] A voltage sampling circuit, coupled to the DC bus, is used to output the first sampling voltage;

[0012] The voltage monitoring comparator U1 receives the first sampled voltage at its non-inverting input and receives a first reference voltage at its inverting input, which corresponds to a preset braking action voltage threshold. When the first sampled voltage exceeds the first reference voltage, it outputs a braking enable signal.

[0013] At least one fault protection comparator receives a monitoring signal reflecting a specific fault state at its non-inverting input and a reference voltage corresponding to the fault protection threshold at its inverting input; when the monitoring signal reaches its corresponding protection threshold, it outputs a second control signal to the driver chip to forcibly shut down the brake.

[0014] The driver chip has its input terminals coupled to the output terminals of the voltage monitoring comparator U1 and the at least one fault protection comparator via wired and logic circuitry. The wired and logic circuitry ensures that the driver chip only outputs a drive signal when all coupled comparators output a level indicating that braking is permitted. If any comparator outputs a shutdown signal indicating a fault, the driver chip immediately stops outputting the drive signal.

[0015] The power switching transistor has its control terminal connected to the output terminal of the driver chip, and its main circuit is connected in series between the braking resistor and the negative terminal of the DC bus.

[0016] Optionally, in the above scheme, the at least one fault protection comparator includes an over-temperature protection comparator, the corresponding monitoring signal of which comes from a temperature sensing circuit.

[0017] The temperature sensing circuit includes a negative temperature coefficient thermistor thermally coupled to the braking resistor or power switch, used to output a second sampling voltage that decreases as the temperature increases.

[0018] When the second sampling voltage is lower than the corresponding second reference voltage, the over-temperature protection comparator outputs the second control signal.

[0019] In the above scheme, optionally, the second reference voltage is generated by the internal operating voltage through a resistor divider, and its voltage value corresponds to a preset shutdown temperature.

[0020] In the above scheme, optionally, the at least one fault protection comparator includes an overvoltage protection comparator, the corresponding monitoring signal of which comes from the voltage sampling circuit or a third sampling voltage obtained by voltage division therefrom;

[0021] When the third sampling voltage exceeds the corresponding third reference voltage, the overvoltage protection comparator outputs the second control signal, and the third reference voltage corresponds to an overvoltage protection threshold that is higher than the braking action threshold.

[0022] In the above scheme, optionally, the line-and-AND logic circuit is composed of multiple diodes, with the anode of each diode connected to the output terminal of the corresponding comparator, and the cathodes of all diodes connected to the input terminal of the driver chip.

[0023] Optionally, the above solution further includes an overload status indication circuit, the circuit comprising:

[0024] A differential amplifier, wherein the non-inverting input terminal receives the first sampled voltage and the inverting input terminal receives the first reference voltage;

[0025] Multiple indicator lights are controlled by the output of the differential amplifier;

[0026] The differential amplifier controls the illumination of different numbers of indicator lights based on the degree of excess of the first sampled voltage relative to the first reference voltage.

[0027] In the above scheme, optionally, the indicator light is a light-emitting diode.

[0028] In the above scheme, optionally, the first reference voltage and each reference voltage corresponding to the at least one fault protection comparator are generated by the internal operating voltage through different resistor voltage divider networks.

[0029] Optionally, in the above scheme, the power supply module is an isolated DC-DC converter.

[0030] Secondly, a servo drive system is provided, including the energy-efficient braking unit as described above.

[0031] Compared with the prior art, this application has at least the following beneficial effects:

[0032] Based on further analysis and research of existing technical problems, this application recognizes that existing technologies suffer from issues such as response delays due to software reliance on protection mechanisms, single-point failure risks due to the deep integration of braking functions with the main controller, and difficulties in fault diagnosis and maintenance caused by the lack of independent status indications for the braking unit itself. By employing a pure hardware comparator architecture, including a voltage monitoring comparator and at least one independent fault protection comparator, and utilizing wire and logic circuits to coordinate the output signals of these comparators to jointly control a single driver chip, a hardware protection network with autonomous decision-making capabilities is constructed. This design enables the detection and shutdown commands for faults such as overvoltage and overtemperature to be generated and executed entirely in real time by hardware circuits, achieving microsecond-level rapid protection response and completely eliminating dependence on the main controller software program. Simultaneously, the unit's self-contained power supply, sampling, comparison, and drive modules ensure independent and safe operation even in the event of main controller failure, fundamentally eliminating the risk of single-point failure. Therefore, this application achieves the technical effect of improving the reliability, safety, and real-time response of the energy-consuming braking unit itself.

[0033] This application also has at least the following beneficial effects:

[0034] 1. Achieved ultra-high reliability and security:

[0035] Full hardware protection with extremely fast response: Over-temperature and over-voltage protection are implemented using independent comparators. The detection and shutdown actions are executed purely in hardware, with a response speed in the microsecond range, far faster than any software loop. This ensures that the main circuit can be cut off immediately in the event of an extreme fault, effectively preventing the fault from escalating (such as MOSFET breakdown or resistor burnout) or even causing a safety accident.

[0036] Independent of the main control system: All protection functions are integrated into the braking unit itself and do not depend on the main control MCU of the servo driver. Even if the main control system program crashes or fails, this braking unit can still autonomously perform its protection duties, realizing a "fail-safe" design and greatly improving the safety level of the entire drive system.

[0037] 2. It achieves excellent cost-effectiveness and ease of use:

[0038] Simplified architecture and extremely low cost: This invention cleverly reuses the core architecture of "comparator + reference voltage". By changing the resistor network and input signal, multiple advanced protection functions are achieved with minimal additional cost (mainly one or two comparators and several resistors), avoiding the use of complex and expensive dedicated protection chips or additional MCUs.

[0039] The logic is clear and easy to set: the protection threshold (such as temperature point, overvoltage point) is determined by the resistance value of a simple voltage divider resistor, which is very convenient to calculate and adjust, and facilitates product serialization or customer customization.

[0040] High integration and easy installation: All functions are integrated into a single board, which connects to the host through a standard interface, simplifying system wiring and improving installation density and overall reliability.

[0041] 3. Enhanced control quality during braking:

[0042] Avoiding invalid oscillations and malfunctions: Precise voltage comparison and drive design ensure the accuracy of braking action. Independent protection mechanisms also prevent false or unnecessary triggering under abnormal conditions (such as momentary interference), making the braking process smoother and more controllable. Attached Figure Description

[0043] Figure 1 This application provides a circuit diagram of an energy-saving braking unit according to one embodiment.

[0044] In the diagram: 1, Basic control circuit of the energy-consuming braking unit; 2, Over-temperature protection circuit of the energy-consuming braking unit; 3, Over-voltage protection circuit of the energy-consuming braking unit; 4, Overload alarm circuit of the energy-consuming braking unit. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0046] In the description of this application: unless otherwise stated, "multiple" means two or more. Expressions such as "including", "comprising", and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0047] Currently, in low-voltage servo drives and similar power electronic systems, there are two main types of energy-saving braking schemes:

[0048] A simple braking scheme using discrete components involves directly connecting a braking resistor and a mechanical relay or a simple semiconductor switch (such as a thyristor) in parallel on the DC bus. When the bus voltage rises, a simple voltage detection circuit triggers the switch to conduct, dissipating energy into the resistor. This scheme lacks independent protection and diagnostic functions.

[0049] Integrated braking unit solution: Some mid-to-high-end drives integrate the braking function into the main controller, using the main control MCU to monitor the bus voltage and control the integrated power switch. While this solution has some software protection logic (such as overvoltage shutdown), its protection function relies entirely on the main control program and typically lacks independent hardware-level fast protection channels and dedicated overload status indication functions. Its alarm information is also mixed in with the drive's general fault codes, hindering rapid location and maintenance.

[0050] The inventors recognize that the existing technical solutions have the following main shortcomings:

[0051] Inadequate and slow protection functions: Simple solutions have almost no protection functions and are prone to damage such as short circuits, open circuits, or continuous overloads, which can lead to the burnout of switching devices or even safety accidents. Integrated solutions rely on the software loop of the main control MCU for protection, which has a slow response speed. In extreme faults (such as power transistor shoot-through), it may not be able to react within microseconds, which may increase the risk of the fault.

[0052] Lack of independent and intuitive status alarms: Existing solutions typically do not provide independent indications of the braking unit's own operating status. When the braking resistor overheats due to frequent operation or when an abnormality occurs in the power circuit, the system cannot proactively and clearly inform the user of "braking unit overload" or "braking unit failure," but can only passively manifest as an overall driver error (such as overvoltage), leading to difficulties in troubleshooting and low maintenance efficiency.

[0053] Insufficient reliability and safety: The simplified solution has a simple circuit, poor anti-interference, and is prone to malfunction or failure. The integrated solution has the risk of "single point of failure". Once the main control MCU malfunctions, the braking and protection functions will be lost, and the system safety cannot be guaranteed.

[0054] Therefore, this application aims to overcome the shortcomings of the prior art and solve the following core technical problems:

[0055] How can we equip the energy-saving braking unit with a fast, independent, and comprehensive hardware protection mechanism (especially overvoltage and overtemperature protection) so that it can autonomously ensure safety even if the control system fails?

[0056] How can we achieve real-time monitoring and intelligent diagnosis of the braking unit's operating status, and provide independent and clear alarm signals in case of overload or failure, so as to improve the maintainability and reliability of the system?

[0057] How can braking function, multiple hardware protections, and status alarm functions be integrated into a single unit with high density and high reliability to achieve a balance between performance, safety, and ease of maintenance?

[0058] In one embodiment, reference Figure 1An energy-saving braking unit is provided, connected between the positive and negative terminals of a DC bus, comprising:

[0059] The power module is used to convert the voltage of the DC bus into a stable internal operating voltage;

[0060] A voltage sampling circuit, coupled to the DC bus, is used to output the first sampling voltage;

[0061] The voltage monitoring comparator U1 receives the first sampled voltage at its non-inverting input and receives a first reference voltage at its inverting input, which corresponds to a preset braking action voltage threshold. When the first sampled voltage exceeds the first reference voltage, it outputs a braking enable signal.

[0062] At least one fault protection comparator receives a monitoring signal reflecting a specific fault state at its non-inverting input and a reference voltage corresponding to the fault protection threshold at its inverting input; when the monitoring signal reaches its corresponding protection threshold, it outputs a second control signal to the driver chip to forcibly shut down the brake.

[0063] The driver chip has its input terminals coupled to the output terminals of the voltage monitoring comparator U1 and the at least one fault protection comparator via wired and logic circuitry. The wired and logic circuitry ensures that the driver chip only outputs a drive signal when all coupled comparators output a level indicating that braking is permitted. If any comparator outputs a shutdown signal indicating a fault, the driver chip immediately stops outputting the drive signal.

[0064] The power switching transistor has its control terminal connected to the output terminal of the driver chip, and its main circuit is connected in series between the braking resistor and the negative terminal of the DC bus.

[0065] In one embodiment, the first reference voltage and each reference voltage corresponding to the at least one fault protection comparator are generated by the internal operating voltage through different resistor divider networks.

[0066] 1. Overall architecture and power supply.

[0067] This unit is a standalone hardware board. Its onboard power module converts a wide range of DC bus voltages into a stable 12V voltage to power all control and protection circuits (comparators, operational amplifiers) on the board. This ensures that the power supply for the control logic is isolated from the main power circuit, improving interference immunity and reliability.

[0068] 2. Core braking control circuit (main function).

[0069] This circuit realizes the basic triggering function of energy consumption braking, and its core is a voltage monitoring comparator (denoted as U1).

[0070] Sampling Input (Positive Terminal, Dynamic Threshold VTH_DC): The DC bus voltage is sampled through a high-precision voltage-dividing resistor network (e.g., composed of four relatively large resistors in series) to obtain a voltage signal VTH_DC that is linearly proportional to the bus voltage. VTH_DC increases as the bus voltage rises.

[0071] Reference Benchmark (Negative Terminal, Fixed Threshold VTH_REF): A stable 12V power supply generates a fixed reference voltage VTH_REF through another group of high-precision voltage-dividing resistors (e.g., two resistors in series). This voltage corresponds to a preset braking action voltage threshold (e.g., when the bus voltage reaches 53V, VTH_DC exceeds VTH_REF).

[0072] Logic and Drive: When the bus voltage is normal, VTH_DC < VTH_REF, and the comparator U1 outputs a low level. When the motor feeds back energy and the bus voltage rises to the braking threshold, VTH_DC > VTH_REF, and the output of the comparator U1 flips to a high level.

[0073] Power Execution: This high-level signal is directly sent to the input pin of the MOSFET gate driver chip (U2). The driver chip then outputs a large current to quickly turn on the power MOSFET (Q1). After Q1 conducts, the braking resistor (R_brake) is connected between the DC bus and the ground, and the energy is dissipated in the form of heat through this resistor, thereby causing the bus voltage to drop back.

[0074] 3. Integrated Hardware Protection Channel (Innovation Core).

[0075] The key innovation of this invention is that two independent hardware protection circuits are seamlessly embedded in the main braking circuit. They have the same architecture as the main braking comparator and cooperate logically to jointly control the same driver chip (U2) to achieve a fault shutdown with "OR" logic.

[0076] In one embodiment, the at least one fault protection comparator includes an over-temperature protection comparator, and its corresponding monitoring signal comes from a temperature sensing circuit;

[0077] The temperature sensing circuit includes a negative temperature coefficient thermistor thermally coupled to the braking resistor or the power switch tube, and is used to output a second sampling voltage that decreases as the temperature rises;

[0078] When the second sampling voltage is lower than the corresponding second reference voltage, the over-temperature protection comparator outputs the second control signal.

[0079] In one embodiment, the second reference voltage is generated by voltage division of the internal working voltage, and its voltage value corresponds to a preset shutdown temperature.

[0080] ① Over-temperature protection channel:

[0081] Purpose: To prevent the braking resistor (R_brake) from overheating due to long-term or frequent operation, which may cause fire risks or component damage.

[0082] Implementation: Add an over-temperature protection comparator (denoted as U3).

[0083] Temperature sampling (positive terminal): The 12V power supply is connected in series with a fixed resistor (such as 5.1kΩ) and a negative temperature coefficient thermistor (NTC) closely mounted to the braking resistor or power device for voltage division. The voltage V_TEMP at this voltage division point decreases as the temperature increases (due to the decrease in the NTC resistance).

[0084] Temperature threshold setting (negative terminal): The 12V power supply is divided by another set of fixed resistors (such as 51kΩ and 10kΩ in series) to generate a fixed temperature protection threshold voltage V_TH_T, whose value corresponds to the preset shutdown temperature (such as 100°C).

[0085] Protection logic: Under normal temperature, the NTC resistance is high, V_TEMP > V_TH_T, and the comparator U3 outputs a high level (allowing braking). When the temperature rises to 100°C, the NTC resistance drops to about 1kΩ, causing V_TEMP < V_TH_T, and the output of the comparator U3 immediately flips to a low level. This low-level signal is sent to the input of the drive chip (U2) to forcefully turn off the MOSFET Q1 and stop braking to achieve temperature reduction.

[0086] In one embodiment, the at least one fault protection comparator includes an over-voltage protection comparator, and its corresponding monitoring signal comes from the voltage sampling circuit or a third sampling voltage obtained by voltage division thereof;

[0087] When the third sampling voltage exceeds the corresponding third reference voltage, the over-voltage protection comparator outputs the second control signal, and the third reference voltage corresponds to an over-voltage protection threshold higher than the braking action threshold.

[0088] ② Input over-voltage protection channel:

[0089] Purpose: To prevent abnormal situations (such as braking resistor open circuit, system failure) from causing the bus voltage to soar beyond the board's safety design limit (such as 63V) and protect the components on the board (especially the power MOSFET) from being breakdown.

[0090] Implementation: Add an over-voltage protection comparator (denoted as U4).

[0091] Dynamic sampling (inverting terminal): Directly reuse the bus voltage sampling signal VTH_DC of the main braking channel, and perform secondary voltage division through a set of voltage dividing resistors (such as 5.1 kΩ and 4.7 kΩ) to obtain V_OVP. V_OVP also increases as the bus voltage increases.

[0092] Overvoltage threshold setting (non-inverting terminal): Divide the voltage of a 12V power supply through fixed resistors (such as two 20 kΩ) to generate a fixed overvoltage protection threshold voltage V_TH_O, whose value corresponds to a preset bus voltage shutdown threshold (such as 63V).

[0093] Protection logic: Under normal voltage, V_OVP < V_TH_O, and the comparator U3 outputs a high level (allowing braking). When the bus voltage abnormally rises beyond 63V, V_OVP > V_TH_O, and the output of the comparator U3 immediately flips to a low level. Similarly, this low level forces the drive chip and MOSFET to turn off, disconnecting the braking unit from the bus to protect its own safety.

[0094] In one embodiment, the wire-AND logic circuit is composed of multiple diodes, the anodes of each diode are respectively connected to the output terminals of the corresponding comparators, and the cathodes of all diodes are commonly connected to the input terminal of the drive chip.

[0095] 4. Cooperative work and control logic

[0096] "Wire-AND" control: The main braking signal (output of U1), over-temperature protection signal (output of U3), and overvoltage protection signal (output of U4) are commonly connected to the input terminal of the drive chip through diodes. If any comparator outputs a low level, it will pull down the drive input terminal and immediately turn off the MOSFET. This achieves a pure hardware "OR" logic shutdown with a response speed in the microsecond level.

[0097] In one embodiment, it further includes an overload status indication circuit, and the circuit includes:

[0098] A differential amplifier, whose non-inverting input terminal receives the first sampling voltage, and the inverting input terminal receives the first reference voltage;

[0099] Multiple indicator lights, controlled by the output of the differential amplifier;

[0100] Wherein, the differential amplifier controls different numbers of indicator lights to light up according to the excess degree of the first sampling voltage relative to the first reference voltage.

[0101] In one embodiment, the indicator lights are light-emitting diodes.

[0102] 5. Overload alarm.

[0103] Purpose: To display the quantity via LED indicators on the board, allowing customers to observe the working status of the energy-saving braking unit and determine whether it has reached an overload state.

[0104] Implementation: Add a differential operational amplifier circuit (denoted as U5).

[0105] The positive input of the operational amplifier (U5) is VTH_DC, the negative input is VTH_REF, and the output current signal controls the three LEDs to turn on and off.

[0106] Alarm logic: When the bus voltage continues to rise, the energy-dissipating braking resistor is insufficient to discharge a large amount of energy, causing VTH_DC to be greater than VTH_REF for a long time. The operational amplifier outputs a current signal to control the LED to turn on and off. The larger VTH_DC is, the more LEDs will light up.

[0107] In one embodiment, the power module is an isolated DC-DC converter.

[0108] In one embodiment, a servo drive system is characterized by including the energy-efficient braking unit provided in the embodiment described above.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. An energy-saving braking unit, connected between the positive and negative terminals of a DC bus, characterized in that, include: The power module is used to convert the voltage of the DC bus into a stable internal operating voltage; A voltage sampling circuit, coupled to the DC bus, is used to output the first sampling voltage; Voltage monitoring comparator U1 receives the first sampled voltage at its non-inverting input terminal; The inverting input receives a first reference voltage, which corresponds to a preset braking action voltage threshold; when the first sampled voltage exceeds the first reference voltage, a braking enable signal is output. At least one fault protection comparator receives a monitoring signal reflecting a specific fault state at its non-inverting input and a reference voltage corresponding to the fault protection threshold at its inverting input. When the monitoring signal reaches its corresponding protection threshold, a second control signal is output to the driver chip to forcibly shut off the brake. The driver chip has its input terminals coupled to the output terminals of the voltage monitoring comparator U1 and the at least one fault protection comparator via wired and logic circuitry. The wired and logic circuitry ensures that the driver chip only outputs a drive signal when all coupled comparators output a level indicating that braking is permitted. If any comparator outputs a shutdown signal indicating a fault, the driver chip immediately stops outputting the drive signal. The power switching transistor has its control terminal connected to the output terminal of the driver chip, and its main circuit is connected in series between the braking resistor and the negative terminal of the DC bus.

2. The energy-saving braking unit according to claim 1, characterized in that, The at least one fault protection comparator includes an over-temperature protection comparator, the corresponding monitoring signal of which comes from a temperature sensing circuit. The temperature sensing circuit includes a negative temperature coefficient thermistor thermally coupled to the braking resistor or power switch, used to output a second sampling voltage that decreases as the temperature increases. When the second sampling voltage is lower than the corresponding second reference voltage, the over-temperature protection comparator outputs the second control signal.

3. The energy-saving braking unit according to claim 2, characterized in that, The second reference voltage is generated by dividing the internal operating voltage through a resistor, and its voltage value corresponds to a preset shutdown temperature.

4. The energy-saving braking unit according to claim 1, characterized in that, The at least one fault protection comparator includes an overvoltage protection comparator, the corresponding monitoring signal of which comes from the voltage sampling circuit or a third sampling voltage obtained by voltage division therefrom; When the third sampling voltage exceeds the corresponding third reference voltage, the overvoltage protection comparator outputs the second control signal, and the third reference voltage corresponds to an overvoltage protection threshold that is higher than the braking action threshold.

5. The energy-saving braking unit according to claim 1, characterized in that, The line-and-AND logic circuit consists of multiple diodes, with the anode of each diode connected to the output of the corresponding comparator, and the cathodes of all diodes connected to the input of the driver chip.

6. The energy-saving braking unit according to any one of claims 1 to 5, characterized in that, It also includes an overload status indication circuit, the circuit comprising: A differential amplifier, wherein the non-inverting input terminal receives the first sampled voltage and the inverting input terminal receives the first reference voltage; Multiple indicator lights are controlled by the output of the differential amplifier; The differential amplifier controls the illumination of different numbers of indicator lights based on the degree of excess of the first sampled voltage relative to the first reference voltage.

7. The energy-saving braking unit according to claim 6, characterized in that, The indicator light is a light-emitting diode.

8. The energy-saving braking unit according to claim 1, characterized in that, The first reference voltage and each reference voltage corresponding to the at least one fault protection comparator are generated by the internal operating voltage through different resistor divider networks.

9. The energy-saving braking unit according to claim 1, characterized in that, The power module is an isolated DC-DC converter.

10. A servo drive system, characterized in that, Includes the energy-saving braking unit as described in any one of claims 1 to 9.

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