Protection control method and circuit for power device circuit and servo driver

Abstract

Provided is a protection control method for a power device circuit, comprising: S1: detecting a desaturation circuit parameter a, a current sampling parameter b, a driving signal parameter c, and a bus voltage parameter d of the power device circuit; S2: setting a power device circuit short-circuit protection threshold A, a current safety threshold B, and a voltage safety threshold C; S3: determining an alarm state of the power device circuit according to the detected parameters a, b, c, d and the thresholds A, B, C, and performing corresponding operations on the power device circuit according to the alarm state. The application protects the driver through current sampling and desaturation circuit on the load side, and can work for a certain time before protection when the power device exceeds a certain large voltage and current, thereby maximizing the performance of the power device.

Description

Technical Field

[0001] This invention relates to the field of intelligent control, and more specifically to protection and control methods, circuits, and servo drivers for power device circuits. Background Technology

[0002] With the development of industrial automation, servo drives are being used more and more widely, and users have higher requirements for their reliability. A servo system is an automatic control system that enables the output controlled variables, such as the position, orientation, and state of an object, to follow any change in the input target value (or given value). It consists of a motion controller, a servo drive, and a servo motor. A servo drive typically includes a rectifier module, an energy storage capacitor, and an inverter module.

[0003] Servo drives have become an indispensable part of our lives, integrated into industry and commerce. In practical operation, short circuits inevitably occur to some extent. Currently, short circuits are classified into two types: load short circuits and bridge arm short circuits. Current technologies protect against both types of short circuits by relying on the desaturation characteristics of the IGBT, then sending a signal to the main control chip for software shutdown. However, due to component aging and other factors, traditional technologies are prone to failure, leading to IGBT protection malfunction and ultimately causing the IGBT to short-circuit and explode.

[0004] Furthermore, in some situations (such as when one upper-bridge IGBT is turned on at a certain moment, and two lower-bridge IGBTs are simultaneously turned on, the current carried by the upper-bridge IGBT is twice that of the lower-bridge IGBT, potentially exceeding the IGBT's limiting parameters), there will be a large voltage and current on the IGBT exceeding its limiting parameters, but the IGBT has not entered the desaturation state. The large current and voltage cause the IGBT module to burn out. This problem has not yet been improved or resolved in the existing technology.

[0005] In the field of motor control, integrated inverter modules consisting of six IGBTs (Insulated Gate Bipolar Transistors) or IPM modules (Intelligent Power Modules) integrating drive and protection circuits are commonly used. The stability of the IGBT drive power supply in integrated inverter modules and IPM modules directly affects the operating state of the IGBTs. When the drive power supply voltage is too low, the drive signal is insufficient to fully turn on the IGBTs. In this case, the on-resistance is high, resulting in significant losses and heat generation, which may burn out the IGBTs.

[0006] Traditional IGBT modules do not integrate corresponding protection circuits. IPM modules generally integrate power supply over- and under-voltage protection. However, in current IPM modules, only the lower bridge arm N-side power supply under-voltage of the six IGBTs can output a protection signal. Although the upper bridge arm P-side power supply can provide protection when under-voltage, it will not output a protection signal. In this case, it is difficult to prevent the main control chip from outputting the PWM signal, which may lead to extreme switching action, resulting in incomplete IGBT conduction, which can damage the module and make it difficult to locate the fault.

[0007] The information disclosed in the background section above is only used to further understand the background of the present invention, and therefore may include information known to those skilled in the art that does not constitute prior art. Summary of the Invention

[0008] This invention provides a control method, circuit, and servo driver for a power device protection circuit, which can quickly and stably shut down the power device when a short circuit occurs or a large current exceeds the power device's limit parameters. Specifically, this invention addresses the following problems: (1) enabling protection even when the power device has not entered desaturation and is subjected to a large current; (2) significantly reducing the failure rate of power devices within the driver; and (3) enabling protection even when the power device lacks a desaturation circuit or the desaturation circuit has failed.

[0009] The first aspect of the present invention provides a protection control method for a power device circuit, comprising: S1: detecting desaturation circuit parameter a, current sampling parameter b, drive signal parameter c, and bus voltage parameter d of the power device circuit; S2: setting a short-circuit protection threshold A, a current safety threshold B, and a voltage safety threshold C for the power device circuit; S3: determining an alarm state of the power device circuit based on the detected parameters a, b, c, and d and the thresholds A, B, and C, and performing corresponding operations on the power device circuit according to the alarm state.

[0010] According to one embodiment of the present invention, the desaturation state of the power device is detected by a desaturation circuit, wherein the desaturation parameter a of the power device circuit is expressed as: 0 when the desaturation circuit is not working, and 1 when the desaturation circuit is working.

[0011] According to one embodiment of the present invention, the driving signal parameter c is expressed as follows: 0 when neither the upper nor lower bridge of the power device circuit has a driving signal output, and 1 when both the upper and lower bridges of the power device circuit have a signal output.

[0012] According to one embodiment of the present invention, the current sampling parameter is a specific value of the current sampling signal after processing, and the bus voltage parameter is the detected actual bus voltage value.

[0013] According to one embodiment of the present invention, the alarm state is related to desaturation circuit failure, load short circuit, power device bridge arm short circuit, power device overvoltage, and power device burnout.

[0014] According to one embodiment of the present invention, when the circuit sampling parameter b > the short-circuit protection threshold A of the power device circuit, it is determined that a load short circuit has occurred in the power device circuit; when the circuit sampling parameter b > the current safety threshold B of the power device circuit, it is determined that the power device in the power device circuit is at risk of burning out; when the voltage across the power device in the power device circuit exceeds the voltage safety threshold C, it is determined that the power device is at risk of burning out.

[0015] According to one embodiment of the present invention, when the desaturation parameter a = 1 and the bus voltage parameter d < the bus voltage safety threshold D of the power device circuit, if the current sampling parameter b ≤ the short-circuit protection threshold A of the power device circuit, and there is no situation where the current sampling parameter b decreases rapidly and the bus voltage parameter d does not increase, the alarm state of the power device circuit is determined to be a first alarm state, where the power device is not short-circuited and the power device is operating normally, and an alarm for desaturation circuit failure is triggered; if the current sampling parameter b ≤ the short-circuit protection threshold A of the power device circuit, and the current sampling parameter b decreases rapidly and the bus voltage parameter d does not increase, the alarm state of the power device circuit is determined to be a second alarm state, where the bridge arm of the power device circuit is short-circuited, and all power devices in the power device circuit are turned off; if the circuit sampling parameter b > the short-circuit protection threshold A of the power device circuit, the alarm state of the power device circuit is determined to be a third alarm state, where the load is short-circuited, and all power devices in the power device circuit are turned off.

[0016] According to one embodiment of the present invention, when d > the bus voltage safety threshold D of the power device circuit, the alarm state of the power device circuit is determined to be the fourth alarm state, the fourth alarm state is the overvoltage of the power device circuit, and all power devices in the power device circuit are turned off.

[0017] According to one embodiment of the present invention, when the desaturation parameter a = 0 and the bus voltage parameter d < the bus voltage safety threshold D of the power device circuit, if the circuit sampling parameter b > the short-circuit protection threshold A of the power device circuit, the alarm state of the power device circuit is determined to be the fifth alarm state, wherein the power device load is short-circuited and the desaturation circuit fails, and all power devices in the power device circuit are turned off; if the current sampling parameter b ≤ the short-circuit protection threshold A of the power device circuit, and the current sampling parameter b decreases rapidly while the bus voltage parameter d does not increase, the alarm state of the power device circuit is determined to be the seventh alarm state, wherein the bridge arm of the power device circuit is short-circuited and the desaturation circuit fails, and all power devices in the power device circuit are turned off.

[0018] According to one embodiment of the present invention, when the desaturation parameter a = 0 and the bus voltage parameter d < the bus voltage safety threshold D of the power device circuit, if the current sampling parameter b ≤ the short-circuit protection threshold A of the power device circuit, and there is no situation where the current sampling parameter b decreases rapidly and the bus voltage parameter d does not increase, if the current sampling parameter does not meet the conditions of b < current safety threshold B and d < voltage safety threshold C of the power device circuit, a timer is set to start counting. When the timer duration exceeds a preset safety time threshold T, the alarm state of the power device circuit is determined to be the sixth alarm state, which is that the power device current of the power device circuit is too large and there is a risk of burnout, and all power devices in the power device circuit are shut down; if the duration of not meeting the conditions of current sampling parameter b < current safety threshold B and bus voltage parameter d < voltage safety threshold C of the power device circuit does not exceed the preset safety time threshold T, the values ​​of the circuit sampling parameter b and the bus voltage parameter are continuously detected until b < B and d < C, at which point the timer is cleared.

[0019] A second aspect of the present invention provides a protection and control circuit for a power device circuit, comprising a voltage detection circuit, a drive circuit, a desaturation circuit, a current sampling circuit, a signal processing circuit, and a controller connected to the power device circuit. The power device circuit includes upper and lower bridge arms containing multiple power devices. The voltage detection circuit detects the voltage on the bus of the power device circuit and feeds back the bus voltage to the controller in real time. The drive circuit receives control signals from the controller and drives the power devices in the power device circuit to turn on and off. The desaturation circuit feeds back the desaturation state of the power devices in the power device circuit to the controller. The current sampling circuit detects the current on the load side in real time. The signal processing circuit converts the current on the load side into a voltage signal and sends it to the controller. The controller generates control signals according to the above method to control the power device circuit.

[0020] A third aspect of the present invention provides a servo driver that uses the protection control method according to the power device circuit described above, or a protection control circuit including the power device circuit described above.

[0021] According to the power device protection circuit control scheme of the present invention, the driver is protected simultaneously by current sampling on the load side and desaturation circuit. It can also operate for a certain period of time before protection when the power device exceeds a certain large voltage or current, so as to maximize the performance of the power device. Attached Figure Description

[0022] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a circuit diagram of the protection control circuit of the IGBT circuit according to an exemplary embodiment of the present invention.

[0024] Figure 2 This is a flowchart of a protection control method for an IGBT circuit according to an exemplary embodiment of the present invention.

[0025] Figure 3 This is a flowchart illustrating the implementation of a protection and control method for an IGBT circuit according to an exemplary embodiment of the present invention. Specific Implementation

[0026] As used herein, the terms "first," "second," etc., can be used to describe elements in exemplary embodiments of the present invention. These terms are used only to distinguish one element from another, and the inherent features or order of the corresponding elements are not limited by the term. Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in common dictionaries are to be interpreted as having the same meaning as in the context of the relevant technical field, and not as having an ideal or overly formal meaning, unless explicitly defined as having such a meaning in this invention.

[0027] Those skilled in the art will understand that the apparatus and methods of the present invention described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments, and the scope of the invention is defined only by the claims. Features illustrated or described in conjunction with an exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are included within the scope of the invention.

[0028] In the following description, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, detailed descriptions of known functions or configurations are omitted to avoid unnecessarily obscuring the key technical aspects of the invention. Furthermore, throughout the description, the same reference numerals always refer to the same circuits, modules, or units, and for the sake of brevity, repeated descriptions of the same circuits, modules, or units are omitted.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, according to the exemplary embodiments of this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Furthermore, it should be understood that one or more of the following methods or aspects can be performed by at least one control unit or controller. The terms "control unit," "controller," "control module," or "main control module" can refer to a hardware device including a memory and a processor. The memory or computer-readable storage medium is configured to store program instructions, and the processor is specifically configured to execute the program instructions to perform one or more processes, which will be further described below. Moreover, it should be understood that, as those skilled in the art will recognize, the following methods can be performed by including a processor in conjunction with one or more other components.

[0031] This invention provides a control scheme for a power device protection circuit. If a power device is short-circuited, even if the desaturation circuit fails, the power device can be shut down in time for protection. The voltage and current of the power device are monitored in real time. When the voltage and current exceed the safe value of the power device but will not burn out the power device, the power device can continue to operate. When the power device has not entered desaturation and there is a risk of burning out, the power device is protected in time.

[0032] In this invention, the power device can be a conventional power device such as IGBT, BJT and MOSFET. Although the following IGBT is used in this invention, other power devices that are suitable for the inventive concept of this invention are also within the protection scope of this invention.

[0033] Figure 1 This is a circuit diagram of the protection control circuit of the IGBT circuit according to an exemplary embodiment of the present invention.

[0034] like Figure 1As shown, IGBT circuits typically use an integrated inverter module consisting of six IGBTs (Insulated Gate Bipolar Transistors) or an IPM module (Intelligent Power Module) that integrates drive and protection circuits. Figure 1 This is a diagram of the overall hardware framework of the present invention. In addition to conventional servo driver components, it also includes a voltage detection circuit, a drive circuit, a desaturation circuit, a current sampling circuit, a signal processing circuit, and a controller connected to the IGBT circuit.

[0035] According to one or more embodiments of the present invention, the voltage detection circuit generally consists of voltage divider resistors and sampling elements, which collect the voltage on the bus and feed the bus voltage back to the controller in real time; the drive circuit generally consists of isolation elements and their peripheral circuits, which turn the IGBT on and off in a timely manner based on the signals given by the controller; the desaturation circuit consists of some basic electronic components, which can feed back the desaturation state of the IGBT to the controller. The system simultaneously determines whether there is a short circuit and whether the desaturation circuit is damaged based on the operating state of the desaturation circuit and the state of the output current sampling terminal. If a short circuit is detected in the output current, but the desaturation circuit is not working, then the desaturation circuit is considered damaged. The current sampling circuit is generally a precision resistor or Hall sensor, which can detect the current on the load side in real time; the signal processing circuit generally converts the current on the load side into a voltage signal and sends it to the controller; the controller generally consists of a main control chip and its peripheral circuits, which are used to receive and send commands.

[0036] According to one or more embodiments of the present invention, during actual operation of the driver, the bus voltage and three-phase output current are detected in real time by the voltage detection circuit and the current sampling circuit, and fed back to the controller, so as to determine whether the driver is at risk of burning out at a certain moment and to take corresponding protective measures.

[0037] Figure 2 This is a flowchart of a protection control method for an IGBT circuit according to an exemplary embodiment of the present invention.

[0038] like Figure 2 As shown, in step S1, the desaturation circuit parameter a, current sampling parameter b, drive signal parameter c, and bus voltage parameter d of the IGBT circuit are detected.

[0039] In step S2, the IGBT circuit short-circuit protection threshold A, current safety threshold B, and voltage safety threshold C are set.

[0040] In step S3, the alarm state of the IGBT circuit is determined based on the detected parameters a, b, c, d and the thresholds A, B, C, and corresponding operations are performed on the IGBT circuit according to the alarm state. The alarm state is related to desaturation circuit failure, load short circuit, IGBT bridge arm short circuit, IGBT overvoltage, and IGBT burnout.

[0041] According to one or more embodiments of the present invention, the alarm states determined by the present invention and the related protective measures implemented are shown in Table 1.

[0042] Table 1

[0043]

[0044]

[0045] Figure 3 This is a flowchart illustrating the implementation of a protection and control method for an IGBT circuit according to an exemplary embodiment of the present invention.

[0046] As shown in the figure, the parameters in the implementation flowchart have the following meanings:

[0047] Desaturation circuit parameter 'a': when the desaturation circuit is not working, a = 0; conversely, when the desaturation circuit is working, a = 1. The desaturation circuit parameter only determines the working state of the desaturation protection circuit and does not affect the operation of the desaturation protection circuit.

[0048] Current sampling parameter b: A specific value of the current sample after signal processing;

[0049] Drive signal parameter c: When there is no drive signal output from either the upper or lower bridge, c = 0; when there is a signal output from either the upper or lower bridge, c = 1.

[0050] Bus voltage parameter d: Feedback value of actual bus voltage;

[0051] Short circuit protection threshold A: Set threshold A. When b > A, it is determined that a load short circuit has occurred.

[0052] Current safety threshold B: Determined by the IGBT itself. When the current flowing through the IGBT exceeds B, the IGBT is at risk of burning out.

[0053] Voltage safety threshold C: Determined by the IGBT itself. When the voltage across the IGBT exceeds C, the IGBT is at risk of burning out.

[0054] The safe threshold D for bus voltage. When the actual bus voltage d exceeds D, the driver is at risk of being damaged due to excessive bus voltage.

[0055] According to one or more embodiments of the present invention, B and C are the maximum current and voltage withstand values ​​given in the selected IGBT manual, and C is the maximum voltage withstand value of the IGBT. For example, if an IGBT module with a specification of 450A 1200V is selected, then the maximum withstand current of the IGBT module is 450A and the maximum withstand voltage is 1200V, wherein the value of C is independent of the bus voltage threshold D. According to one or more embodiments of the present invention,

[0056] When a = 1 and d < D

[0057] At this time, the desaturation circuit is working, and the bus voltage does not exceed the IGBT's voltage safety threshold. There are two reasons why the desaturation circuit is working: one is that the IGBT enters the desaturation state; the other is that due to external interference or a fault in the desaturation circuit, the circuit falsely reports a=1.

[0058] Now we need to determine whether b is greater than A (i.e., ... Figure 3 In the judgment box (b > A?), if a load short circuit occurs, the current b sampled will definitely be greater than the current safety threshold B. If this condition occurs, it can be determined that a load short circuit has occurred, and the IGBT enters the desaturation state. If b ≤ A, then no load short circuit has occurred. When a bridge arm short circuit occurs in the IGBT circuit, the load side current will decrease rapidly because the load is not connected to the short circuit loop. Due to the huge energy release caused by the short circuit, the bus voltage d will not increase. Therefore, it is determined whether a bridge arm short circuit has occurred by judging whether b decreases rapidly and d increases. Therefore, when the desaturation circuit is working (a = 1), the above two conditions form three situations: no short circuit (alarm 1), bridge arm short circuit (alarm 2), and load short circuit (alarm 3). The advantage of the present invention is that even if the desaturation circuit malfunctions, the driver can still work, thereby reducing the losses in the actual operation of the driver.

[0059] According to one or more embodiments of the present invention, when d > D, the bus voltage is too high, and the IGBT must be disconnected in time to stop the driver from working; otherwise, the bus capacitor and IGBT are at risk of burning out.

[0060] According to one or more embodiments of the present invention, when a = 0 and d < D, the desaturation circuit does not work, and the bus voltage does not exceed the safe threshold D of the IGBT bus voltage. Similarly, there are two situations: one is that the circuit is normal and the IGBT does not enter the desaturation state; the other is that the desaturation circuit is damaged, and even if the IGBT enters the desaturation state, the desaturation circuit does not work.

[0061] At this point, we determine whether b is greater than A (i.e., ...). Figure 3In the conditional statement (b > A?), if a load short circuit occurs, b > A must be satisfied, indicating a load short circuit in the IGBT, damage to the desaturation circuit, triggering alarm 6, and stopping the IGBT. In existing solutions, the IGBT would inevitably explode in this situation, damaging the driver. This solution protects the driver.

[0062] If b ≤ A, then further check if b decreases rapidly and d increases. Use this condition to determine if a bridge arm short circuit has occurred. If so, alarm 7 is triggered, and the IGBT stops working. Similarly, in existing technical solutions, the IGBT will inevitably explode in this situation, damaging the driver. This technical solution can protect the driver.

[0063] If no short circuit occurs, it is necessary to determine whether the IGBT will be damaged due to excessive voltage or current. Using the calculation formula in the IGBT's manual, calculate the safe time t that the IGBT can withstand in the current state based on the voltage and current b and d on the IGBT (note that the actual t should be smaller than the calculated time for module failure, leaving a certain safety margin). Start timing T from this point (by setting a timer). When T exceeds the set safe time t, the IGBT is at risk of burning out, and alarm 6 is triggered. Otherwise, continue judging until b < B and d < C, at which point the IGBT is no longer at risk. Then, the timer parameter T is reset to zero, and the driver works normally.

[0064] Table 1 shows the meanings of the seven alarm states. Different alarms can accurately pinpoint driver problems, eliminating the need for tedious testing and troubleshooting.

[0065] According to one or more embodiments of the present invention, the present invention also provides a servo driver that uses the protection and control method of the power device circuit described above, or a protection and control circuit including the power device T circuit described above.

[0066] The solution of this invention effectively protects the power device from large voltages and currents, while allowing the driver to operate in its current state for a period of time. This maximizes the performance of the power device.

[0067] According to one or more embodiments of the present invention, the logic of the controller in the system of the present invention can implement the processing of the processes in the system described above using encoded instructions (e.g., computer and / or machine-readable instructions) stored on a non-transitory computer and / or machine-readable medium (e.g., hard disk drive, flash memory, read-only memory, optical disk, digital multifunction disk, cache, random access memory, and / or any other storage device or storage disk), storing information for any period of time (e.g., extended time periods, permanent, transient instances, temporary caches, and / or information caches) in the non-transitory computer and / or machine-readable medium. As used herein, the term "non-transitory computer-readable medium" is explicitly defined to include any type of computer-readable storage device and / or storage disk, excluding propagated signals and transmission media.

[0068] According to one or more embodiments of the present invention, the logic of the controller in the system of the present invention can be implemented using control circuitry (control logic, main control system, or control module), which may include one or more processors and may also internally include non-transitory computer-readable media. Specifically, the main control system or control module may include a microcontroller (MCU). The processor used to implement the processing of the logic in the system of the present invention may be, such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, etc.). The processor may be coupled thereto and / or may include memory / storage devices and may be configured to execute instructions stored in the memory / storage devices to implement various applications and / or operating systems running on the controller in the present invention.

[0069] The accompanying drawings and detailed description of the invention, cited above as examples, serve to explain the invention but do not limit its meaning or scope as described in the claims. Therefore, those skilled in the art can readily make modifications from the above description. Furthermore, those skilled in the art can remove some of the components described herein without degrading performance, or add other components to improve performance. Additionally, those skilled in the art can change the order of steps in the method described herein depending on the process or equipment environment. Therefore, the scope of the invention should not be determined by the embodiments described above, but rather by the claims and their equivalents.

[0070] Although the invention has been described in conjunction with embodiments now considered to be achievable, it should be understood that the invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent configurations included within the spirit and scope of the appended claims.

Claims

1. A protection and control method for a power device circuit, comprising: S1: Detect the desaturation circuit parameters a, current sampling parameters b, drive signal parameters c, and bus voltage parameters d of the power device circuit; S2: Set the short-circuit protection threshold A, current safety threshold B, and voltage safety threshold C for circuits containing power devices; S3: Determine the alarm status of the power device circuit based on the detected parameters a, b, c, d and the thresholds A, B, C, and perform corresponding operations on the power device circuit according to the alarm status; in: When the desaturation parameter a=1 and the bus voltage parameter d< the bus voltage safety threshold D of the power device circuit: If the current sampling parameter b ≤ the short-circuit protection threshold A of the power device circuit, and there is no situation where the current sampling parameter b decreases rapidly and the bus voltage parameter d does not increase, the alarm state of the power device circuit is determined to be the first alarm state. The first alarm state is that the power device is not short-circuited and the power device is working normally, and the alarm is triggered by the desaturation circuit fault. If the current sampling parameter b ≤ the short-circuit protection threshold A of the power device circuit, and the current sampling parameter b decreases rapidly while the bus voltage parameter d does not increase, the alarm state of the power device circuit is determined to be the second alarm state, which is a short circuit in the bridge arm of the power device circuit, and all power devices in the power device circuit are turned off. If the circuit sampling parameter b > the short-circuit protection threshold A of the power device circuit, the alarm state of the power device circuit is determined to be the third alarm state, which is a load short circuit, and all power devices in the power device circuit are turned off.

2. The method according to claim 1, wherein the desaturation state of the power device circuit is detected by a desaturation circuit, and the desaturation parameter a of the power device circuit is expressed as: 0 when the desaturation circuit is not working, and 1 when the desaturation circuit is working.

3. The method according to claim 2, wherein the driving signal parameter c is expressed as follows: 0 when neither the upper nor lower bridge of the power device circuit has a driving signal output, and 1 when the upper and lower bridges of the power device circuit have a signal output.

4. The method according to claim 3, wherein the current sampling parameter is a specific value of the current sampling signal after processing, and the bus voltage parameter is the detected actual bus voltage value.

5. The method according to claim 1, wherein, The alarm status is related to desaturation circuit failure, load short circuit, power device circuit bridge arm short circuit, power device circuit overvoltage, and power device burnout.

6. The method according to claim 1, wherein, When the circuit sampling parameter b > the short-circuit protection threshold A of the power device circuit, it is determined that a load short circuit has occurred in the power device circuit. When the circuit sampling parameter b > the power device circuit current safety threshold B, it is determined that the power device in the power device circuit is at risk of burning out. When the voltage across the power device in a power device circuit exceeds the voltage safety threshold C, it is determined that the power device is at risk of burning out.

7. The method according to claim 1, wherein, When d > the voltage safety threshold D of the power device circuit, the alarm state of the power device circuit is determined to be the fourth alarm state, which is the overvoltage of the power device circuit, and all power devices in the power device circuit are shut down.

8. The method according to claim 1, wherein, Where the desaturation parameter a=0 and the bus voltage parameter d< the voltage safety threshold D of the power device circuit, If the circuit sampling parameter b > the short-circuit protection threshold A of the power device circuit, the alarm state of the power device circuit is determined to be the fifth alarm state. The fifth alarm state is that the power device load is short-circuited and the desaturation circuit fails, and all power devices in the power device circuit are turned off. If the current sampling parameter b ≤ the short-circuit protection threshold A of the power device circuit, and the current sampling parameter b decreases rapidly while the bus voltage parameter d does not increase, the alarm state of the power device circuit is determined to be the seventh alarm state. The seventh alarm state is that the bridge arm of the power device circuit is short-circuited and the desaturation circuit fails, and all power devices in the power device circuit are turned off.

9. The method according to claim 1, wherein, When the desaturation parameter a = 0 and the bus voltage parameter d < the voltage safety threshold D of the power device circuit, if the current sampling parameter b ≤ the short-circuit protection threshold A of the power device circuit, and there is no situation where the current sampling parameter b decreases rapidly and the bus voltage parameter d does not increase, then... If the current sampling parameters do not meet the conditions that b < current safety threshold B and bus voltage parameter d < voltage safety threshold C of the power device circuit, the timer is set to start counting. When the timer duration exceeds the preset safety time threshold T, the alarm state of the power device circuit is determined to be the sixth alarm state. The sixth alarm state is that the power device current in the power device circuit is too large and there is a risk of burnout, and all power devices in the power device circuit are turned off. If the conditions that current sampling parameter b < current safety threshold B and bus voltage parameter d < voltage safety threshold C of power device circuit are not met for a duration exceeding the preset safety time threshold T, the values ​​of sampling parameter b and bus voltage parameter will be continuously detected until b < B and d < C, at which point the timer will be cleared.

10. A protection and control circuit for a power device circuit, comprising a voltage detection circuit, a drive circuit, a desaturation circuit, a current sampling circuit, a signal processing circuit, and a controller connected to the power device circuit, wherein the power device circuit includes upper and lower bridge arms containing multiple power devices, wherein... The voltage detection circuit is used to detect the voltage on the power device circuit bus and feed the bus voltage back to the controller in real time. The driving circuit is used to receive control signals from the controller to drive the power devices in the power device circuit to turn on and off. The desaturation circuit is used to feed back the desaturation state of the power devices in the power device circuit to the controller. The current sampling circuit is used to detect the current on the load side in real time; The signal processing circuit is used to convert the current on the load side into a voltage signal and send it to the controller; The controller is used to generate control signals to control the power device circuit according to the method of any one of claims 1-9.

11. A servo driver that uses the protection control method for a power device circuit according to any one of claims 1-9, or includes the protection control circuit for a power device circuit according to claim 10.

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