Short circuit and high current load identification method and apparatus

Abstract

The application provides a short circuit and large current load identification method and device, and relates to the technical field of low-voltage alternating current power supply protection. In the application, firstly, the instantaneous current is monitored during the conduction of the controlled power switch, and the controlled power switch is turned off when the current reaches the current limiting condition; secondly, based on the alternating current phase, a plurality of mutually separated trial conduction windows are arranged in the subsequent alternating current half cycle; then, the controlled power switch is turned on in each trial conduction window, the instantaneous current over-limit state and the load end output voltage establishment state are obtained, the current hit sequence and the voltage establishment sequence are formed; finally, according to whether the voltage establishment sequence meets the preset establishment condition and the current over-limit condition, it is determined whether the short circuit or abnormal load, the large current starting process or the starting completion, and the turning off, the continuous trial or the resumption of the continuous conduction are maintained. Based on the above, the problem that the short circuit and the large current starting load are difficult to distinguish in the prior art can be improved.

Description

Technical Field

[0001] This application relates to the field of low-voltage AC power supply protection technology, and more specifically, to a method and apparatus for identifying short-circuit and high-current loads. Background Technology

[0002] Loads such as lighting drivers, large capacitors after rectifier bridges, transformers, and motors generate large starting currents at the moment of connection. A real short circuit also manifests as a rapid increase in instantaneous current above a threshold. Therefore, in low-voltage AC power supply protection scenarios, the instantaneous peak values ​​of short-circuit current and starting surge current may overlap.

[0003] Existing technologies typically use single peak value, single over-limit, or fixed delay for judgment, which makes it difficult to simultaneously meet the requirements of both rapid short-circuit shutdown and normal connection of loads with large starting current.

[0004] Under the above judgment method, increasing the current threshold will increase the short-circuit discharge energy; extending the judgment time will exacerbate the stress on power devices and lines; and simple automatic retry may repeatedly supply energy in a continuous short circuit if the load voltage is not observed.

[0005] In other words, in the existing technology, there is a problem that when the short-circuit current and the peak value of the startup surge may overlap, it is difficult to reliably distinguish between the short-circuit state and the high-current startup state while limiting the energy delivery time each time. Summary of the Invention

[0006] In view of this, the purpose of this application is to provide a short-circuit and high-current load identification method and device based on controlled trial conduction and output voltage establishment characteristics, so as to improve the problem in the prior art that it is difficult to reliably distinguish between short-circuit state and high-current start-up state while limiting the power delivery time each time when the short-circuit current and the peak value of the start-up surge may overlap.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] A method for identifying short-circuit and high-current loads is applied to an AC power supply circuit, wherein the AC power supply circuit is equipped with a controlled power switch, an instantaneous current detection channel, a load-side output voltage detection channel, and an AC phase detection channel, including:

[0009] The instantaneous current is monitored during the conduction of the controlled power switch, and the controlled power switch is turned off when the instantaneous current reaches the current limiting condition.

[0010] Based on the communication phase, multiple separate trial conduction windows are arranged within the subsequent half-week of communication.

[0011] The controlled power switch is turned on in each test conduction window, and the instantaneous current over-limit state and load-end output voltage establishment state in the test conduction window are obtained to form the current hit sequence and voltage establishment sequence of the current test round.

[0012] When the voltage establishment sequence does not meet the preset establishment conditions, it is determined to be a short circuit or abnormal load and remains off;

[0013] When the voltage establishment sequence meets the preset establishment conditions and the current hit sequence indicates that there is still an instantaneous current exceeding the limit, it is determined that the load is in a high current start-up process and the next trial round is executed in the subsequent AC half-cycle.

[0014] When the voltage establishment sequence meets the preset establishment conditions and there is no instantaneous current over-limit in the current test round, the high current start-up process is determined to be over and continuous conduction is restored.

[0015] In a preferred embodiment of this application, in the above-described short-circuit and high-current load identification method, before any trial conduction window begins, the instantaneous current hardware comparison unit is first armed, and then the controlled power switch is turned on; when an instantaneous current exceeding the limit is detected, the controlled power switch is turned off by the interrupt service routine.

[0016] In a preferred embodiment of this application, in the above-described short-circuit and high-current load identification method, when an instantaneous current exceeding the limit is detected, the instantaneous current sampling value is first latched, and the load terminal output voltage is acquired by injecting an analog-to-digital conversion channel, and then the controlled power switch is turned off.

[0017] In a preferred embodiment of this application, in the above-mentioned short-circuit and high-current load identification method, the preset establishment conditions include: the current test round completes a preset number of test conduction windows, and the number of valid sampling points with the load-side output voltage higher than the output voltage threshold reaches the confirmation number.

[0018] In a preferred embodiment of this application, in the above-mentioned short-circuit and high-current load identification method, any of the following situations are not counted as valid sampling points that meet the preset establishment conditions: invalid sampling, missed test conduction window, or load terminal output voltage not higher than the output voltage threshold.

[0019] In a preferred embodiment of this application, the above-mentioned short-circuit and high-current load identification method further includes: setting at least one of the following: maximum number of test cycles, maximum cumulative conduction time, and power device thermal constraint; and keeping the controlled power switch off and entering a locked state when the corresponding upper limit is reached but the high-current start-up process has not yet been determined.

[0020] In a preferred embodiment of this application, in the above-described short-circuit and high-current load identification method, before the first conduction, the zero point of the instantaneous current detection channel is calibrated in the off state of the controlled power switch, and the input voltage is obtained by reading the power metering chip; if the input voltage or the AC phase does not meet the reliable condition, conduction is prohibited.

[0021] In a preferred embodiment of this application, in the above-described short-circuit and high-current load identification method, the plurality of trial conduction windows in a 10ms AC half-cycle begin at 2.0ms, 3.5ms, 5.0ms, 6.5ms and 8.0ms after zero crossing, respectively, and the maximum duration of each trial conduction window is 650µs.

[0022] In a preferred embodiment of this application, in the above-described short-circuit and high-current load identification method, the output voltage threshold is 10V to 50V, and the number of confirmed cases is 2 to 5.

[0023] This application also provides a short-circuit and high-current load identification device, comprising: a current monitoring module for monitoring instantaneous current during the conduction of a controlled power switch, and turning off the controlled power switch when the instantaneous current reaches a current-limiting condition; a window arrangement module for arranging multiple mutually separated test conduction windows based on the AC phase in subsequent AC half-cycles; and a sequence formation module for turning on the controlled power switch in each test conduction window and acquiring the instantaneous current over-limit state and the load-side output voltage establishment state in the test conduction window to form a current hit sequence for the current test round. The system includes a voltage establishment sequence; a short-circuit determination module, used to determine a short circuit or abnormal load and keep it off when the voltage establishment sequence does not meet the preset establishment conditions; a start-up determination module, used to determine that the load is in a high-current start-up process and execute the next test round in the subsequent AC half-cycle when the voltage establishment sequence meets the preset establishment conditions and the current hit sequence indicates that there is still an instantaneous current over-limit; and a recovery control module, used to determine that the high-current start-up process ends and restore continuous conduction when the voltage establishment sequence meets the preset establishment conditions and there is no instantaneous current over-limit in the current test round.

[0024] Beneficial effects:

[0025] The method and apparatus for identifying short-circuit and high-current loads based on controlled test conduction and output voltage establishment characteristics provided in this application firstly monitors the instantaneous current during the conduction of the controlled power switch and turns off the controlled power switch when the current limiting condition is reached, thus limiting the energy delivered each time. Secondly, based on the AC phase, multiple mutually separated test conduction windows are arranged in the subsequent AC half-cycle, and multiple short test conduction windows with AC phase alignment are used as active excitations. Then, the instantaneous current over-limit state and the load-end output voltage establishment state are jointly acquired in each test conduction window to form a current hit sequence and a voltage establishment sequence. The sequence formed by multiple test conduction windows reflects the changes in load impedance and energy storage state with phase and test rounds. Finally, the combined characteristics of the two sequences are used to distinguish between short-circuit or abnormal loads, high-current start-up processes, and start-up completion. Based on the above, since the ability of the load-side output voltage to be established is directly related to the short-circuit impedance, the current rapidly exceeds the limit during a short circuit, and the load-side voltage usually cannot be established continuously. Although a high-current starting load will exceed the limit, its input capacitance, magnetization state, or speed will change with the controlled energy delivery, and the load-side voltage can be established and gradually stabilize. Thus, the two types of states can be distinguished without using the peak value as the sole classification criterion, thereby improving the problem of difficulty in distinguishing between short-circuit and high-current starting loads in the prior art.

[0026] Meanwhile, since each test is subject to the dual constraints of instantaneous current hardware protection and maximum window time, each energy delivery is limited to a short window and interrupted at any time by hardware protection, which helps to reduce the discharge energy under continuous short circuit conditions; for starting loads that can establish voltage but still exceed the limit, energy is delivered in batches, so that their energy storage or magnetization state is gradually established, which helps to balance current limiting and starting pass capability.

[0027] Furthermore, by excluding invalid sampling from valid sampling points, the maximum number of test cycles, the maximum cumulative conduction time, and the thermal constraints of power devices to handle uncertain states, and by maintaining the off state and entering a locked state even when the high-current start-up process has not yet ended after reaching the corresponding upper limit, it helps to prevent infinite testing on boundary loads and improves the safety of protection. The number of test windows, phase, width, output voltage threshold, and number of confirmations can all be parameterized, which helps to migrate the above identification method to different rated currents, different phase windows, and different solid-state switch structures. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0029] Figure 1A flowchart illustrating the short-circuit and high-current load identification method provided in this application embodiment;

[0030] Figure 2 A schematic diagram of the hardware structure of the short-circuit and high-current load identification device provided in the embodiments of this application;

[0031] Figure 3 A timing diagram illustrating a five-timeslot trial conduction within an AC half-cycle, provided for an embodiment of this application;

[0032] Figure 4 A schematic diagram illustrating the decision relationship between the current hit sequence and the voltage establishment sequence provided in the embodiments of this application;

[0033] Figure 5 A comparison diagram of the actual short-circuit waveform of the device provided in this application embodiment and the actual short-circuit waveform of similar products;

[0034] Figure 6 A comparison chart of historical lamp start-up test peak values ​​provided for embodiments of this application;

[0035] Figure 7 This is a qualitative comparison chart showing the successful start-up of the lamp load provided in this embodiment of the application and the lamp start-up protection of similar products. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0037] Combination Figure 2 The short-circuit and high-current load identification device provided in this application embodiment can employ a main controller with hardware threshold comparison functionality. The main controller's first analog-to-digital converter input is connected to an independent instantaneous current detection circuit, its second analog-to-digital converter input is connected to an output voltage detection circuit, its zero-crossing input is connected to an AC zero-crossing detection circuit, and its switch control output is connected to a bidirectional power switch via an isolation drive circuit. The energy metering chip RN8209D provides the main controller with input voltage, current, leakage current, active power, and energy consumption via a serial bus. The instantaneous current detection circuit and the load-side output voltage detection circuit are independent of the energy metering chip RN8209D. It should be noted that the specific main controller model and port allocation are determined by the product hardware configuration and do not constitute a limitation on the identification method of this application.

[0038] Combination Figure 1 This application also provides a method for identifying short-circuit and high-current loads. The following will describe... Figure 1 The specific process shown will be explained in detail.

[0039] S1 monitors the instantaneous current during the conduction of the controlled power switch, and turns off the controlled power switch when the instantaneous current reaches the current limiting condition.

[0040] In this embodiment, before normal closing, the controlled power switch remains off. The main controller calibrates the zero point of the instantaneous current detection channel while the controlled power switch is off, and reads the input voltage from the energy metering chip RN8209D. If the input voltage or AC phase does not meet the reliable condition, conduction is prohibited. That is, subsequent conduction is only permitted after a reliable input voltage and a reliable zero-crossing are obtained.

[0041] In this embodiment, after obtaining a reliable zero-crossing, the instantaneous current hardware comparison unit is first armed within the short atomic region, and then the controlled power switch is turned on to avoid a gap where the controlled power switch is on but the protection is not armed. The instantaneous current hardware comparison unit is an analog watchdog with threshold comparison functionality, which monitors the upper and lower limits of the instantaneous current sampling in the armed state.

[0042] If the instantaneous current sampling exceeds the upper or lower limit, the analog-to-digital conversion interrupt is executed with high priority, and the interrupt service routine shuts down the controlled power switch. Specifically, when an instantaneous current exceeding the limit is detected within the test conduction window, the interrupt service routine first latches the instantaneous current sampling value, triggers the injection into the analog-to-digital conversion channel to directly convert the load-side output voltage, and then shuts down the controlled power switch through fast register operations. Current prototype measurements show that this sampling-then-shutdown timing increases the sampling time by approximately 23.6µs. It should be noted that this value is a measurement result from an embodiment and cannot replace response verification under different device and clock conditions.

[0043] S2, based on the AC phase, arranges multiple mutually separate trial conduction windows within the subsequent half-cycle of the AC phase.

[0044] In this embodiment, after the initial instantaneous current exceeding the limit and subsequent shutdown, the main controller waits for the next true zero crossing. For 50Hz AC, this is approximately 10ms per half-cycle. Combined with... Figure 3 For example, five trial conduction windows are sequentially arranged at 2.0ms, 3.5ms, 5.0ms, 6.5ms, and 8.0ms after the zero crossing. The maximum duration of each trial conduction window is 650µs, and adjacent trial conduction windows remain off, thereby obtaining load response at different phases. That is, multiple trial conduction windows in a 10ms AC half-cycle start at 2.0ms, 3.5ms, 5.0ms, 6.5ms, and 8.0ms after the zero crossing, respectively, with a maximum duration of 650µs for each trial conduction window.

[0045] It should be noted that the number, phase, and width of the test conduction windows are not limited and can be selected according to the power grid frequency, the safe operating area of ​​the switching devices, the load type, and the thermal design. For example, in one alternative implementation, the window phase can be represented as a half-cycle normalized ratio; in another alternative implementation, 3 to 8 test conduction windows can be used; and the window width can be adjusted based on the results of the previous test round. Regardless of the parameter combination used, the above identification method is not limited to specific values ​​of 2.0ms, 3.5ms, 5.0ms, 6.5ms, 8.0ms, and 650µs, to cover other implementations of the same technical concept.

[0046] S3, turn on the controlled power switch in each test conduction window, and obtain the instantaneous current over-limit state and load-end output voltage establishment state in the test conduction window to form the current hit sequence and voltage establishment sequence of the current test round.

[0047] In this embodiment, the instantaneous current hardware comparison unit is re-armed before the start of each test conduction window, and then the controlled power switch is turned on. If an instantaneous current exceeds the limit again within 650µs, the load terminal output voltage is collected first and then the controlled power switch is turned off in the manner described in S1 above; if no limit exceeds the limit, the load terminal output voltage is collected at the end of the window and then the controlled power switch is turned off.

[0048] In this embodiment, the load-side output voltage signal is centered at 1.65V, with an absolute deviation taken and converted into a voltage value. Currently, a value higher than 50V is considered established. That is, the output voltage threshold can be set within the range of 10V to 50V, and the number of confirmations can be set within the range of 2 to 5. In one embodiment, the output voltage threshold is 50V and the number of confirmations is 5.

[0049] Based on this, for each test conduction window of the current test round, the instantaneous current is recorded to determine whether it exceeds the limit again and whether the load-side output voltage is effectively established, forming a current hit sequence and a voltage establishment sequence. It should be noted that the current hit sequence can also include the time, direction, duration, or latching amplitude of the limit exceedance; the voltage establishment condition can also be combined with the output voltage slope, the number of consecutive points, the growth rate of adjacent test rounds, or the ratio of the load-side output voltage to the input voltage. Regardless of the feature used, the current limiting event and the load-side voltage response are observed jointly within the controlled window, rather than being classified solely by peak current.

[0050] S4. When the voltage establishment sequence does not meet the preset establishment conditions, it is determined to be a short circuit or abnormal load and is kept off.

[0051] S5, when the voltage establishment sequence meets the preset establishment conditions and the current hit sequence indicates that there is still an instantaneous current exceeding the limit, it is determined that the load is in a high current start-up process and the next trial round is executed in the subsequent AC half-cycle.

[0052] S6, when the voltage establishment sequence meets the preset establishment conditions and there is no instantaneous current over-limit in the current test round, the high current start-up process is determined to end and continuous conduction is restored.

[0053] Combination Figure 4 In this embodiment, the preset establishment conditions include: the current test round completes a preset number of test conduction windows, and the number of valid sampling points with the load-side output voltage higher than the output voltage threshold reaches the confirmation number. For example, a unified judgment must be made after all five test conduction windows are completed; by default, all output voltage sampling points in the five windows are required to be established. Invalid sampling, missed test conduction windows, or load-side output voltage not higher than the output voltage threshold are not counted as valid sampling points meeting the preset establishment conditions.

[0054] In detail, if all five points are established and the entire group does not exceed the limit again, the startup is considered complete, and continuous conduction is restored. If the five points are established but the limit is still exceeded, it indicates that the load can build up voltage but the surge has not yet subsided, and the next AC half-cycle is entered to execute the next trial cycle. If the five points are insufficient, it is treated as a short circuit or abnormal load, and the load is kept off and locked. In other words, during a short circuit, the current rapidly exceeds the limit, and the load-side voltage usually cannot be continuously built up. Although a high-current start-up load may exceed the limit, its input capacitance, magnetization state, or speed will change with the controlled power supply, and the load-side voltage can be built up and gradually stabilize.

[0055] In this embodiment, at least one of a maximum number of test cycles, a maximum cumulative conduction time, and a power device thermal constraint is set. If the high-current startup process is not determined to have ended even after reaching the corresponding upper limit, the controlled power switch remains off and enters a locked state. For example, a maximum of 50 test cycles that meet the voltage establishment conditions are executed. If the process still cannot exit, it is locked, thereby preventing infinite testing on the boundary load.

[0056] In this embodiment, after a short circuit is confirmed, the device remains off and enters a locked state. The current product's safety task attempts automatic reclosing after 20 seconds, observes for 60 seconds after reclosing, with a default maximum of 3 attempts; if a short circuit occurs again, it re-enters the waiting state, and manual reset is required upon reaching the limit. It should be noted that this automatic reclosing is a recovery strategy after a fault and is not a necessary step for short circuit and high-current load identification in this application.

[0057] Combination Figure 2This application also provides a short-circuit and high-current load identification device. The short-circuit and high-current load identification device may include a current monitoring module, a window arrangement module, a sequence formation module, a short-circuit determination module, a start-up determination module, and a recovery control module.

[0058] The current monitoring module is used to monitor the instantaneous current during the conduction of the controlled power switch, and to turn off the controlled power switch when the instantaneous current reaches the current limiting condition. In this embodiment, the current monitoring module can be used to perform... Figure 1 For details regarding the current monitoring module in step S1, please refer to the previous description of step S1.

[0059] The window arrangement module is used to arrange multiple mutually separate trial conduction windows within the subsequent half-cycle of the AC circuit, based on the AC phase. In this embodiment, the window arrangement module can be used to perform... Figure 1 For details regarding step S2 shown, please refer to the previous description of step S2 for information about the window arrangement module.

[0060] The sequence forming module is used to activate the controlled power switch within each test conduction window and acquire the instantaneous current over-limit state and load-side output voltage establishment state within that test conduction window, so as to form the current hit sequence and voltage establishment sequence for the current test round. In this embodiment, the sequence forming module can be used to perform... Figure 1 For details regarding step S3 shown, please refer to the previous description of step S3 for information about the sequence forming module.

[0061] The short-circuit determination module is used to determine a short circuit or abnormal load and maintain shutdown when the voltage establishment sequence does not meet the preset establishment conditions. In this embodiment, the short-circuit determination module can be used to perform... Figure 1 For details regarding the short-circuit determination module shown in step S4, please refer to the previous description of step S4.

[0062] The startup determination module is used to determine that the load is in a high-current startup process and execute the next trial round in the subsequent AC half-cycle when the voltage establishment sequence meets the preset establishment conditions and the current hit sequence indicates that there is still an instantaneous current exceeding the limit. In this embodiment of the application, the startup determination module can be used to execute Figure 1 For details regarding step S5 shown, please refer to the preceding description of step S5 for information about the startup determination module.

[0063] The recovery control module is used to determine the end of the high-current start-up process and restore continuous conduction when the voltage establishment sequence meets the preset establishment conditions and there is no instantaneous current over-limit in the current test round. In this embodiment, the recovery control module can be used to execute... Figure 1 For details regarding the recovery control module in step S6, please refer to the preceding description of step S6.

[0064] The technical effects of the embodiments of this application will be described below with reference to experimental data. It should be noted that the following sets of data are all test records of the embodiments. Since the prototype, circuit, time base, trigger and vernier conditions are not completely consistent, the corresponding waveforms are only used for qualitative description and are not used to calculate the performance improvement ratio.

[0065] The first set of data consists of lamp start-up tests conducted on August 13, 2026. The peak values ​​recorded for direct mains start-up of 8 and 9 lamps were approximately 338A and 394A, respectively. In the early stage, with a wave-by-wave current limiting setting of 180A, the peak values ​​recorded for 8 and 9 lamps under 5ms conditions were approximately 242A and 257A, respectively, after approximately 12 and 22 start-ups. Under 3ms conditions, there were samples of start-up failures and samples that succeeded after increasing the number of start-ups. Combined with... Figure 6 This data demonstrates that controlled, phased power delivery can initiate large surge loads while limiting single-impact loads, and also indicates that overly conservative trial parameters may lead to startup failure. It should be noted that the above lamp tests used early 3ms, 5ms, and 7ms macroscopic conduction interval schemes to illustrate the controlled, phased power delivery phenomenon, and are not intended as a quantitative basis for the current joint criterion of five 650µs time slots per half-week and output voltage identification accuracy.

[0066] The second set of data consists of the actual starting current waveform records of the lamps on August 26, 2026. The main time base for each waveform is 10ms / div. The oscilloscope display shows the starting current as a decaying oscillating AC waveform, with absolute values ​​of approximately 220A to 396A at the positive and negative poles, demonstrating that the peak starting current of the tested lamp load can reach several hundred amperes and decays with frequency. Since the screenshots do not simultaneously show the power switch control, zero-crossing, and output voltage channels, this set of data is only used to illustrate the characteristics of the starting current.

[0067] The third set of data includes the waveform of successful startup of this machine with a lamp load of approximately 550A and the protection waveform of similar products when starting a lamp with a lamp load of approximately 300A. Combined with... Figure 7 The waveform of this device, under a main time base of 500ms / div, displays multiple controlled pulses before transitioning to a stable AC current. The extreme values ​​during the controlled phase are approximately 156A / -186A and 180A / -175A. The waveform of similar products shows repeated operation under approximately 300A lamp start-up conditions before entering protection. This set of data illustrates that the method in this application effectively balances current limiting and start-up throughput; due to differences in equipment, wiring, and triggering conditions, it is used for qualitative comparison.

[0068] The fourth set of data consists of the actual short-circuit waveforms of this machine and those of similar products. Combined with... Figure 5 The main time base of the waveforms on this machine is 20ms / div, and the recorded extreme current values ​​are approximately 196A / -161A, 196A / -161A, 169A / -12A, and 186A / -136A, respectively. Similar products have main time bases of 20ms / div and 50ms / div, with extreme values ​​of approximately 130A / -93A and 256A / -262A, respectively. Visually, the action pulse clusters on this machine are more concentrated, indicating a shortened overall protection process. However, due to inconsistencies in the prototype, time base, trigger, and vernier, this data is not used to calculate the shortening ratio.

[0069] Based on the above, the short-circuit and high-current load identification method and apparatus provided in this application monitor the instantaneous current during the conduction of the controlled power switch and turn it off when the current limiting condition is reached. Multiple mutually separate test conduction windows are arranged based on the AC phase. Within each test conduction window, the instantaneous current exceeding the limit state and the load-side output voltage establishment state are jointly acquired, forming a current hit sequence and a voltage establishment sequence. These two sequences are used to distinguish between short-circuit or abnormal loads, high-current startup processes, and startup completion. Since the ability of the load-side output voltage to establish is a characteristic directly related to the short-circuit impedance, and each test is subject to the dual constraints of instantaneous current hardware protection and the maximum window time, the energy delivered each time is limited. Thus, while limiting the energy delivery time each time, short-circuit and high-current startup loads can be distinguished, thereby improving the problem of difficulty in distinguishing between short-circuit and high-current startup loads in the prior art.

[0070] It is understood that the above-described apparatus and methods can be implemented in other ways. Each block in the flowchart and block diagram may represent a module, program segment, or part of code, and these modules may be executed in a different order than that described herein. The above-described functional modules may be integrated into a single processing unit or may exist physically separately.

[0071] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0072] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for identifying short-circuit and high-current loads, applied to an AC power supply circuit, wherein the AC power supply circuit is equipped with a controlled power switch, an instantaneous current detection channel, a load-side output voltage detection channel, and an AC phase detection channel, characterized in that, include: The instantaneous current is monitored during the conduction of the controlled power switch, and the controlled power switch is turned off when the instantaneous current reaches the current limiting condition. Based on the communication phase, multiple separate trial conduction windows are arranged within the subsequent half-week of communication. Within each test conduction window, the controlled power switch is turned on, and the instantaneous current over-limit state and load-end output voltage establishment state within the test conduction window are obtained to form the current hit sequence and voltage establishment sequence for the current test round. When the voltage establishment sequence does not meet the preset establishment conditions, it is determined to be a short circuit or abnormal load and remains off; When the voltage establishment sequence meets the preset establishment conditions and the current hit sequence indicates that there is still an instantaneous current exceeding the limit, it is determined that the load is in a high current start-up process and the next trial round is executed in the subsequent AC half-cycle. When the voltage establishment sequence meets the preset establishment conditions and there is no instantaneous current over-limit in the current test round, the high current start-up process is determined to be over and continuous conduction is restored.

2. The short-circuit and high-current load identification method according to claim 1, characterized in that, Before any trial conduction window begins, the instantaneous current hardware comparison unit is first armed, and then the controlled power switch is turned on; when an instantaneous current exceeding the limit is detected, the controlled power switch is turned off by the interrupt service routine.

3. The short-circuit and high-current load identification method according to claim 2, characterized in that, When an instantaneous current exceeding the limit is detected, the instantaneous current sampling value is first latched, and the load terminal output voltage is acquired through the injection analog-to-digital conversion channel. Then, the controlled power switch is turned off.

4. The short-circuit and high-current load identification method according to claim 1, characterized in that, The preset establishment conditions include: the current test round completes a preset number of test conduction windows, and the number of valid sampling points with the load-side output voltage higher than the output voltage threshold reaches the confirmation number.

5. The short-circuit and high-current load identification method according to claim 4, characterized in that, In cases where sampling is invalid, the test conduction window is missed, or the output voltage at the load end is not higher than the output voltage threshold, the sampling point that meets the preset establishment conditions will not be counted.

6. The short-circuit and high-current load identification method according to claim 1, characterized in that, Also includes: Set at least one of the following: maximum number of test cycles, maximum cumulative conduction time, and power device thermal constraints; if the high-current start-up process has not yet ended when the corresponding upper limit is reached, keep the controlled power switch off and enter a locked state.

7. The short-circuit and high-current load identification method according to claim 1, characterized in that, Before the first conduction, the zero point of the instantaneous current detection channel is calibrated in the off state of the controlled power switch, and the input voltage is obtained by reading the power metering chip; if the input voltage or the AC phase does not meet the reliable condition, conduction is prohibited.

8. The short-circuit and high-current load identification method according to claim 1, characterized in that, Within a 10ms half-cycle of communication, the multiple trial conduction windows are set after the zero-crossing time; the trial conduction windows are isolated from each other, the number of windows is 3 to 8, and the maximum duration of each trial conduction window is 50μs to 1000μs.

9. The short-circuit and high-current load identification method according to claim 4, characterized in that, The output voltage threshold is 10V to 50V, and the number of confirmations is 2 to 5.

10. A short-circuit and high-current load identification device, characterized in that, include: A current monitoring module is used to monitor the instantaneous current during the conduction of the controlled power switch, and to turn off the controlled power switch when the instantaneous current reaches the current limiting condition. The window arrangement module is used to arrange multiple mutually separate trial conduction windows within the subsequent half-cycle of the AC phase. The sequence forming module is used to turn on the controlled power switch in each test conduction window and obtain the instantaneous current over-limit state and the load terminal output voltage establishment state in the test conduction window to form the current hit sequence and voltage establishment sequence of the current test round. The short circuit determination module is used to determine a short circuit or abnormal load and keep the circuit off when the voltage establishment sequence does not meet the preset establishment conditions; The start-up determination module is used to determine that the load is in a high-current start-up process and to perform the next trial round in the subsequent AC half-cycle when the voltage establishment sequence meets the preset establishment conditions and the current hit sequence indicates that there is still an instantaneous current exceeding the limit. The recovery control module is used to determine that the high-current start-up process has ended and restore continuous conduction when the voltage establishment sequence meets the preset establishment conditions and there is no instantaneous current over-limit in the current test round.

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