A programmable power supply detection method and system

Abstract

The present application relates to the technical field of power supply electrical performance test, and discloses a programmable power supply detection method and system. The application firstly sets sampling nodes at the output end of the measured power supply and the load access end, collects the voltages of the two nodes through the same independent collection channel in time, obtains internal read-back values, and establishes the time correspondence between the internal read-back values and the voltages of the two nodes; collects data under different load currents, output voltages and residence times, and sets an unloading observation stage; analyzes the measured power supply body deviation and connection link deviation according to the internal difference value and the link difference value, judges the source of slow-changing deviation in combination with the loaded time, load current and corresponding position temperature, judges the measured power supply body state after verifying the connection integrity and the connection health state, thereby improving the accuracy of deviation source judgment and abnormal position determination in the loaded detection of the programmable power supply.

Description

Technical Field

[0001] This invention relates to the field of power supply electrical performance testing technology, specifically to a programmable power supply testing method and system. Background Technology

[0002] In the final inspection, incoming material inspection, aging re-inspection, and metrological verification processes of programmable power supplies, it is usually necessary to connect an electronic load to detect the output voltage and output current under different load conditions, and compare the detection results or the internal readback values ​​of the power supply with the set values ​​and specified limits to determine the output performance of the power supply. For example, authorized invention patent application CN117031346B discloses a rapid testing circuit and device for power supply equipment, which detects the output status of the power supply through an electronic load instrument, a reference voltage module, and voltage and current detection modules. Another example is authorized invention patent application CN110764012B, which discloses a DC power supply performance parameter testing method, which reduces the impact of voltage drop caused by connector contact resistance on the test results by performing power measurement and voltage measurement separately.

[0003] However, in actual load testing, the power supply under test (DUT) and the electronic load are typically connected via power cables, connectors, and test fixtures. These connections have contact resistance, which can be affected by factors such as connection tightness, contact surface condition, and current-carrying heat generation, causing an additional voltage drop between the DUT's output and the load. This additional voltage drop, along with the DUT's own output deviation, is reflected in the test results, making it difficult to determine whether the detected deviation originates from the DUT or an external connection based solely on load measurements. Furthermore, existing testing methods typically rely on measurements at one or a few load operating points for judgment, which is inconsistent with the changes in load current and operating conditions. The deviation due to time variation lacks further differentiation; when the power supply's internal settings and readbacks use the same or related reference benchmarks, a slow change in the reference benchmark may cause the set value and the readback value to change simultaneously, making it difficult to detect the actual output deviation in a timely manner based solely on the internal readback results; this may cause abnormalities in the connection part to be mistaken for abnormalities in the power supply itself, or the power supply's own output abnormalities to be masked by voltage drops generated by external connections, thereby reducing the accuracy of test results and causing inconsistencies in the test conclusions between different test stations; therefore, the existing technology still has the technical problem of different errors superimposing each other during load testing, making it difficult to accurately distinguish the source of error and determine the location of abnormalities. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a programmable power supply detection method and system, which solves the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A programmable power supply detection method, comprising:

[0007] Sampling nodes are set at the output end of the power supply under test and the load input end. The voltage of the two nodes is collected in time by the same independent acquisition channel, and the internal readback value of the power supply under test is obtained.

[0008] Establish the time correspondence between the internal readback value and the voltage of the two nodes;

[0009] The load current, output voltage, and dwell time are changed sequentially to collect corresponding data, and an unloading observation phase is set.

[0010] Based on the relationship between the internal readout value and the output node voltage, as well as the relationship between the voltage changes of the two nodes, the deviation of the power supply under test and the external connection deviation are distinguished respectively.

[0011] By combining the relationship between each deviation and the changes in time, load current and corresponding location temperature, the source of slow deviation is determined. First, the external connection status is verified, and then the power supply under test that meets the testing conditions is judged.

[0012] Furthermore, sampling nodes are set at the output terminal of the power supply under test and the load input terminal, and the voltages of the two nodes are collected in a time-division manner by the same independent acquisition channel, including:

[0013] The terminal sampling node set at the output end of the power supply under test and the load sampling node set at the load input end are respectively connected to the same independent acquisition channel through measurement leads that do not carry power current.

[0014] The independent acquisition channel switches between terminal sampling nodes and load sampling nodes through a channel selection component, and acquires the voltage of the corresponding nodes in sequence;

[0015] When the power supply under test has multiple independent outputs, each output channel is set with a corresponding terminal sampling node and load sampling node.

[0016] When the power supply under test enables the remote sensing function, a sensing sampling node is set at the actual access location of the remote sensing line, and the voltage at that location is collected through the independent acquisition channel.

[0017] Furthermore, obtain the internal readback values ​​of the power supply under test, including:

[0018] Read the internal readback voltage through the communication interface of the power supply under test; when the power supply under test provides the internal readback current, read the internal readback current.

[0019] Before load testing, check the measurement polarity, output channel, and acquisition range under no-load or minimum stable load conditions;

[0020] When the sampled value reaches the upper limit of the current range or the acquisition device generates an over-range state, it switches to a higher range;

[0021] When the internal readback value is unavailable, record the internal readback anomaly and retain the actual measured voltage at the terminal and the actual measured voltage at the load terminal.

[0022] Furthermore, the time correspondence between the internal readback value and the voltage of the two nodes is established, including:

[0023] The detection control equipment records the corresponding time of the detection data using a local clock;

[0024] The corresponding time of the internal readback value is determined based on the timestamp of the internal readback data, the trigger time, the latch time, or the time when the readback request is sent and the time when the response is returned.

[0025] The actual measured voltage at the terminal and the actual measured voltage at the load terminal are recorded according to the actual sampling time.

[0026] When the corresponding time points are in the same stable range, they form the same set of detection data. When the communication response fluctuates, the data is repeatedly read back within the stable range and data that crosses the working state switch is removed.

[0027] Furthermore, by sequentially changing the load current, output voltage, and dwell time, corresponding data are collected, including:

[0028] Keep the output voltage of the power supply under test constant, set multiple load current operating states in order from low to high, and repeat some load current operating states in order from high to low as needed for testing.

[0029] Maintain stable load current and set multiple output voltage operating states;

[0030] The load current and output voltage for each operating state are determined based on the allowable operating range of the power supply and electronic load under test.

[0031] Once each working state enters a stable range, corresponding data is collected according to either short or long dwell time.

[0032] Furthermore, an uninstallation observation phase is set up, including:

[0033] Between partial load operation states, keep the output voltage setting and output enable state of the power supply under test unchanged, and adjust the electronic load to no-load state or minimum stable load state.

[0034] Data is collected after the power supply and electronic load under test enter the corresponding stable range.

[0035] After completing the unloading observation, adjust the electronic load to the next load-bearing working state;

[0036] When the power supply under test experiences current limiting, over-temperature, or other protection conditions, the current adjustment is stopped and the system returns to the previous stable operating state.

[0037] Furthermore, based on the relationship between the internal readback value and the output node voltage, as well as the relationship between the voltage changes of the two nodes, the deviation of the power supply under test and the external connection deviation are distinguished, including:

[0038] The internal difference is determined by comparing the internal readback voltage with the actual measured voltage at the terminal, and the link difference is determined by comparing the actual measured voltage at the terminal with the actual measured voltage at the load end.

[0039] The equivalent resistance of the connection is determined based on the change of the link difference under different load currents, and the link difference is compared under no-load or minimum stable load conditions, load increase process, load decrease process, and different dwell times.

[0040] Based on the internal differences at low, intermediate, and high output voltages, we analyze fixed deviation, proportional deviation, and segmented deviation, and analyze the slow-varying deviation based on the internal differences at different residence times.

[0041] Furthermore, by combining the relationship between each deviation and the changes in time, load current, and corresponding location temperature, the sources of slow-varying deviations are determined, including:

[0042] The link difference and internal difference are respectively mapped to the load time and load current, and the link difference is mapped to the connection side temperature and the internal difference is mapped to the body side temperature.

[0043] By combining data obtained under no-load or minimum stable load conditions, as well as during load increase and decrease, the changes of link difference and internal difference with time, load current and corresponding location temperature are compared.

[0044] The confidence level of attribution for slow-varying bias is determined based on the degree of consistency among the comparison results.

[0045] When temperature data is unavailable, the judgment is made based on the changes over time and load current.

[0046] Furthermore, first verify the external connection status, and then determine the power supply under test that meets the testing conditions, including:

[0047] Verify connection integrity based on the corresponding relationship of sampling nodes, measurement polarity, and link difference under no-load or minimum stable load conditions;

[0048] Verify the connection health status based on the allowable connection voltage drop, connection equivalent resistance, and historical reference values ​​of connection equivalent resistance;

[0049] After the connection integrity and connection health status meet the requirements, check the time correspondence, the data of key load current and output voltage operating status, and the internal readback status.

[0050] The state of the power supply under test is determined by fixed deviation, proportional deviation, segmented deviation, and slowly varying deviation.

[0051] On the other hand, the present invention provides a programmable power supply detection system, comprising:

[0052] Sampling and acquisition module: used to set sampling nodes at the output end of the power supply under test and the load input end, and to collect the voltage of the two nodes in a time-division manner by the same independent acquisition channel, and to obtain the internal readback value of the power supply under test;

[0053] Time correspondence module: used to establish the time correspondence between the internal readback value and the voltage of the two nodes;

[0054] Operating status control module: used to sequentially change the load current, output voltage and dwell time and collect the corresponding data, as well as set an unloading observation phase between partial load operating states;

[0055] Deviation Analysis Module: Used to determine the deviation of the power supply under test and the external connection deviation based on the relationship between the internal readout value and the change of the output node voltage, as well as the relationship between the changes of the voltages of the two nodes.

[0056] The detection and judgment module is used to determine the source of slow deviation by combining the relationship between the deviation and the change of load current and the temperature at the corresponding location, and to make a status judgment on the power supply under test that meets the detection conditions after verifying the external connection status.

[0057] Compared with the prior art, the present invention provides a programmable power supply detection method and system, which has the following beneficial effects:

[0058] 1. This invention sets sampling nodes at the output end and load input end of the power supply under test, and uses the same independent acquisition channel to collect the voltage of the two nodes in a time-division manner, and establishes a time correspondence between the internal readback value and the external measured voltage; combined with different load currents, output voltages, dwell times and unloading observation stages, it analyzes the changes of internal difference and link difference with load current, load time and corresponding temperature, and judges the power supply under test after verifying the integrity and health of the connection. This reduces the impact of contact resistance and current-carrying temperature rise of power cables, connectors and test fixtures on the test results, improves the accuracy of judging the source of deviation and determining the abnormal location in load testing, and improves the consistency of test conclusions at different testing stations.

[0059] 2. This invention sets multiple load current and output voltage operating states and collects detection data in conjunction with short-term dwell, long-term dwell, and unload observation phases. It establishes a time correspondence between the internal readout value and the measured voltage at the terminal and the measured voltage at the load end. It compares the internal difference and link difference under different operating states and different load times, and analyzes the changes in the internal difference with the output voltage and the changes in the internal difference and link difference with the load time. This enables the detection of fixed deviation, proportional deviation, segmented deviation, and slowly varying deviation, reducing the missed detection of local deviations and slowly varying deviations when judging based on only a single load operating state or internal readout results, and improving the detection coverage under different output states and continuous load conditions. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of a programmable power supply detection method according to the present invention;

[0061] Figure 2 This is a schematic diagram showing the connection of the sampling nodes and independent acquisition channels of the present invention;

[0062] Figure 3 This is a schematic diagram showing the correspondence between the internal readback value and the voltage time of the two nodes in this invention;

[0063] Figure 4 This is a schematic diagram of the multiple working states and unloading observation and detection process of the present invention;

[0064] Figure 5 This is a schematic diagram illustrating the internal difference and link difference analysis of this invention;

[0065] Figure 6 This is a schematic diagram illustrating the source and detection / judgment of slow-varying deviation in this invention;

[0066] Figure 7 This is a schematic diagram of a programmable power supply detection system according to the present invention. Detailed Implementation

[0067] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] Example 1: Figure 1 - Figure 6 A programmable power supply detection method is presented, including:

[0069] Sampling nodes are set at the output end of the power supply under test and the load input end. The voltage of the two nodes is collected in time by the same independent acquisition channel, and the internal readback value of the power supply under test is obtained.

[0070] Establish the time correspondence between the internal readback value and the voltage of the two nodes;

[0071] The load current, output voltage, and dwell time are changed sequentially to collect corresponding data, and an unloading observation phase is set.

[0072] Based on the relationship between the internal readout value and the output node voltage, as well as the relationship between the voltage changes of the two nodes, the deviation of the power supply under test and the external connection deviation are distinguished respectively.

[0073] By combining the relationship between each deviation and the changes in time, load current and corresponding location temperature, the source of slow deviation is determined. First, the external connection status is verified, and then the power supply under test that meets the testing conditions is judged.

[0074] The programmable power supply testing method described in this application is applied to a programmable DC power supply testing station with digital setting and digital readback functions. It can also be applied to programmable DC power supplies, multi-output programmable power supplies, bidirectional programmable power supplies, and power modules with the same output control and readback functions, for final production inspection, incoming material inspection, post-aging re-inspection, post-repair re-inspection, or metrological verification.

[0075] The power supply under test is connected to the electronic load via power cables, connectors, and test fixtures; the detection and control equipment sends output voltage setting commands and output enable commands to the power supply under test through a communication interface, and reads the internal readback voltage of the power supply under test; when the power supply under test can provide internal readback current, it also reads the internal readback current; the detection and control equipment simultaneously controls the electronic load to change the load current.

[0076] The testing station is equipped with an independent acquisition channel separate from the internal readback channel of the power supply under test, which is used to acquire the measured voltage at the output terminal and the electronic load input terminal of the power supply under test. Depending on the testing needs, a connection-side temperature sensor can be set near the power cable, connector or test fixture, and a body-side temperature sensor can be set on the casing of the power supply under test to acquire the temperature at the corresponding location of the connection link and the power supply body under test, respectively.

[0077] In this embodiment, the rated voltage, rated current, allowable output deviation, allowable connection voltage drop, allowable input current of the electronic load, allowable power of the electronic load, acquisition range, and protection conditions of the power supply under test are determined based on the product specifications of the corresponding model of the power supply under test, the electronic load equipment manual, the design requirements of the power cable and connector, the design requirements of the test fixture, and the test operation documents. When the relevant documents do not directly specify a certain test parameter, the corresponding parameter is determined based on the repeated measurement results of the same model of power supply under test at the same test station, with the same connection method and the same acquisition conditions.

[0078] The normal fluctuation range referred to in this embodiment refers to the normal variation range of voltage, current or corresponding difference obtained by repeated measurements when the power supply under test, electronic load, independent acquisition channel and connection link are all in normal working condition and maintain the same output voltage, the same load current, the same acquisition range and the same connection method.

[0079] The normal fluctuation range can be determined based on the actual variation range in the continuous repeated measurement results, and corrected in combination with the resolution, repeatability and calibration results of the independent acquisition channel and the current range; when the product specification of the power supply under test, the technical documents of the acquisition equipment or the test operation documents have specified the corresponding repeatability allowable range, the corresponding specification shall be adopted; when the model of the power supply under test, the acquisition range, the test fixture or the connection method changes, the corresponding normal fluctuation range shall be re-determined.

[0080] The stable range referred to in this embodiment is the time interval during which the power supply under test is not in the output adjustment, current limiting or protection state, the actual load current of the electronic load has reached the currently set load current, and the changes of the terminal measured voltage, the load measured voltage and the actual load current are all within the corresponding normal fluctuation range during continuous sampling; the internal readback value, the terminal measured voltage and the load measured voltage used for comparison of the same working state are all obtained from the corresponding stable range.

[0081] Specifically, such as Figure 2 As shown: When establishing a test connection, the power supply under test (UTP) is connected to an electronic load via a power cable, connector, and test fixture. Terminal sampling nodes and load sampling nodes are set at the output end of the UTP and the input end of the electronic load, respectively. The terminal sampling node is set at the conductive connection part of the output terminal of the corresponding output channel of the UTP, and is located on the power side of the interface between the UTP and the power cable or test fixture. The load sampling node is set at the conductive part of the input end of the electronic load, and is located on the load side of the connection interface. The power cable, connector, test fixture, and corresponding connection parts between the terminal sampling node and the load sampling node constitute the connection link to be tested.

[0082] The terminal sampling node and the load sampling node are connected to the same independent acquisition channel through measurement leads that do not carry power current. The independent acquisition channel can be switched between the terminal sampling node and the load sampling node through a low thermoelectric relay, an analog switch that meets the requirements of the measured voltage and input impedance, or other channel selection components suitable for voltage measurement. The two switching branches preferentially use the same or similar wire materials, connection methods and switching devices. After the channel switching is completed, the measured voltage of the corresponding node is read after the action time of the channel selection component and the establishment time of the independent acquisition channel.

[0083] The terminal sampling node and the load sampling node use the same independent acquisition channel, which allows the two sampling nodes to share the same signal conditioning, range switching, and analog-to-digital conversion channels. This reduces measurement deviations caused by zero-point differences, gain differences, and temperature differences when using different acquisition channels. For the same independent acquisition channel, when the measurement result is affected by both proportional error and additive offset, the additive offset can be canceled or weakened after the difference between the measured values ​​of the two sampling nodes, while the proportional error still acts on the node voltage difference in the same proportion. Therefore, before testing, the zero point, proportional relationship, and repeatability corresponding to the current acquisition range should be confirmed to meet the testing requirements based on the calibration record of the independent acquisition channel or the calibration result of the testing station.

[0084] The detection and control equipment reads the output channel information of the power supply under test, determines the terminal sampling node and load sampling node based on the current output channel, and establishes a correspondence between the two sampling nodes and the current output channel. The correspondence is as follows: the terminal sampling node is located at the conductive connection point of the output terminal of the current output channel; the load sampling node is located at the conductive part of the input terminal of the electronic load that forms an actual power connection with the current output channel through power cables, connectors, and test fixtures. Both the terminal sampling node and the load sampling node correspond to the current output channel, and the power cables, connectors, test fixtures, and corresponding connection points between them constitute the connection link to be tested corresponding to that output channel. The detection and control equipment records... The corresponding detection information includes at least the fields of sampling node identifier, measurement polarity, channel selection address, output channel, and connection link identifier. Under no-load or minimum stable load conditions, the measurement polarity, output channel, and current acquisition range of the two sampling nodes are checked. When the output channel corresponding to the terminal sampling node and the load sampling node is inconsistent, the subsequent load testing is paused, and the power connection, sampling leads, channel selection components, and sampling node configuration are checked. When the power supply under test has multiple independent outputs, each output channel establishes a corresponding terminal sampling node and load sampling node, and only the measurement data obtained from the same output channel are combined into the same operating point data.

[0085] When the power supply under test enables the remote sensing function, a sensing sampling node can be set at the actual connection location of the remote sensing line, and the voltage at that location can be collected through the independent acquisition channel to verify the actual connection location of the remote sensing line and its potential relationship; when the power supply under test does not enable the remote sensing function, a sensing sampling node does not need to be set.

[0086] The detection and control equipment simultaneously reads the internal readback value through the communication interface of the power supply under test. The internal readback value includes at least the internal readback voltage, and may also include the internal readback current if the power supply under test can provide the internal readback current. The internal readback value is formed by the readback channel of the power supply under test itself and is used to characterize the current output state reflected by the internal readback channel of the power supply under test. It is not used as an external measurement reference independent of the power supply under test. With the above settings, the internal readback voltage, the terminal measured voltage, and the load measured voltage can be obtained separately in the same detection round, wherein the terminal measured voltage and the load measured voltage are both obtained by the same independent acquisition channel.

[0087] Before conducting load testing, verify the connection relationship, measurement polarity, and acquisition range of the sampling nodes; when the power supply under test is allowed to run under no-load, reduce the electronic load current to zero; when the power supply under test has a minimum load requirement, make the electronic load work at the lowest stable load allowed by the product specifications; in this state, sequentially acquire the actual measured voltage of the terminals and the actual measured voltage of the load terminals, and verify the measurement polarity, output channel, and current acquisition range of the two sampling nodes.

[0088] Under no-load or minimum stable load conditions, the voltage drop across the connection link caused by the load current is reduced compared to the normal load condition. Therefore, the potential relationship between the measured voltage at the terminal and the measured voltage at the load end should be consistent with the output polarity and actual power connection relationship of the power supply under test. When the sampling polarity is reversed, the sampling value exceeds the current range, the measurement result cannot enter a stable state after channel switching, the output channel corresponding to the terminal sampling node and the load sampling node is inconsistent, or the actual connection position of the sensing sampling node and the remote sensing line is inconsistent, the subsequent load test should be suspended, and the power connection, sampling lead, channel selection component, and sampling node configuration should be checked.

[0089] The acquisition range is determined based on the rated voltage of the power supply under test and the current output setting. Priority is given to selecting a range that can cover the highest output voltage that may occur under the current operating conditions, while also meeting the detection resolution requirements. When the sampled value reaches the upper limit of the current range or the acquisition device experiences an over-range state, the range is switched to a higher range, and the voltage of the corresponding node is reacquired after the independent acquisition channel re-enters a stable state. If the maximum available range of the current device still cannot cover the output voltage of the power supply under test, the output voltage or load is not increased further, and the current detection cycle is stopped.

[0090] When the internal readback value is unavailable, but both the terminal sampling node and the load sampling node can collect data normally, the internal readback anomaly is recorded, and the actual measured voltage of the terminal and the actual measured voltage of the load are retained for subsequent connection link detection. Before the internal readback value is restored to validity, a complete body-side deviation judgment based on the internal readback value is not formed.

[0091] After completing the above processing, a basic data record for the current detection round is formed. The basic data record includes at least the following fields: sampling node identifier, output channel, measurement polarity, acquisition range, internal readback status, data validity status, internal readback value, terminal measured voltage, and load measured voltage. The basic data record will be used to establish the time correspondence between the internal readback value and the measured voltage of each node.

[0092] Specifically, such as Figure 3 As shown: The detection control equipment uses the local clock as the unified time reference for the current detection cycle, and records the corresponding time for the internal readback value, the actual voltage of the terminal and the actual voltage of the load end, so that different data can be compared according to the same working state.

[0093] When the internal readback data returned by the power supply under test has a valid timestamp, that timestamp is used to determine the corresponding time of the internal readback value. When the power supply under test supports hardware triggering or readback latching, the trigger time or latching time can be used as the corresponding time of the internal readback value. When the power supply under test neither provides a valid timestamp nor supports hardware triggering or readback latching, the detection and control device records the time the readback request is sent. Record the response return time when a readback response is received. and will to This refers to the time interval in which the internal readback value may be formed.

[0094] When determining the corresponding time of internal readback values ​​using communication request and response times, first check whether the time interval is within the stable range of the current operating point; during continuous readback, if the time intervals corresponding to each internal readback value do not cross load current switching, output voltage adjustment, or unloading state switching, then the current communication state is determined to meet the time correspondence requirements; under this condition, it can be taken as... and The intermediate time is used as the approximate corresponding time of the internal readback value, that is... And simultaneously record the round-trip communication time. The purpose of using the intermediate time is to limit the internal readback value to the corresponding stable operating state, rather than using this time as the only way to determine the actual sampling time inside the power supply under test.

[0095] The independent acquisition channel records the actual terminal voltage and the actual load voltage at the actual sampling time. When the corresponding time of the internal readback value, the sampling time of the terminal voltage, and the sampling time of the load voltage are all within the same stable range, the corresponding data are established. This avoids directly comparing data obtained under different operating conditions when the load current is switched, the output voltage is adjusted, or the output state is not yet stable.

[0096] The start time of the stable interval is determined based on the time required for the power supply under test, electronic load, and independent acquisition channel to complete the state transition. Specifically, the output settling time of the power supply under test can be determined according to the corresponding product specification or operating point switching test record; the adjustment time of the electronic load can be determined according to the electronic load equipment manual or the testing station debugging record; the settling time of the independent acquisition channel can be determined based on the action time of the channel selection component, the range switching time of the acquisition device, and the stabilization time of the acquisition device. When the relevant technical data does not provide a specific time, after the operating state transition, the measured terminal voltage, the measured load voltage, and the actual load current are continuously acquired until the changes in the above data all fall within the normal fluctuation range of the corresponding operating point. The subsequent continuous time period is then considered the stable interval.

[0097] When communication round-trip time fluctuations cause the time interval corresponding to the internal readback value to span the working state switch, a hardware triggering method can be used. The detection and control equipment sends the same trigger signal to the power supply under test and the independent acquisition channel, so that the power supply under test latches the internal readback value according to the trigger signal, and at the same time, the independent acquisition channel starts node sampling. Since the terminal sampling node and the load sampling node share the same independent acquisition channel, the two nodes can be sampled sequentially in the same stable interval. Alternatively, the terminal sampling node and the load sampling node can be sampled separately in two consecutive trigger cycles in which the output voltage and load current are the same. When using the latter method, it should be confirmed that the output state of the power supply under test and the electronic load state have not changed between the two trigger cycles.

[0098] When the power supply under test does not support hardware triggering and the communication response exhibits random fluctuations, multiple readbacks can be performed continuously within the same stable interval. For example, 5 to 9 readback interactions can be performed continuously, recording the sending time of each readback request, the response return time, and the round-trip time, while repeatedly obtaining the measured voltage of the corresponding node. 5 to 9 times can be selected as a range of repetitions suitable for conventional testing stations. The selection should ensure that all readback interactions can be completed within the same stable interval and that multiple round-trip time records can be obtained. The actual number of readbacks (5, 7, or 9) can be determined based on the round-trip time of a single communication and the duration of the current stable interval. If increasing the number of readbacks may cause subsequent readbacks to approach the end of the stable interval, the number of readbacks should not be increased.

[0099] For the aforementioned multiple readback data, priority is given to data whose communication round-trip times are relatively concentrated and whose corresponding time intervals are all within a stable range; data whose communication round-trip times deviate significantly from the main distribution range of the current multiple communications, or whose corresponding time intervals are close to the working state switching position, are not used to establish a correspondence with the terminal measured voltage and the load measured voltage; if the time intervals corresponding to the internal readback values ​​cannot be stably kept in the same working state after multiple readbacks, only the internal readback values ​​within the stable range that can confirm the correspondence are retained; if a correspondence still cannot be established, the internal readback time state is recorded as abnormal, and the corresponding internal readback values ​​are not used for the deviation analysis of the tested power supply side.

[0100] When the same independent acquisition channel performs time-division sampling of terminal sampling nodes and load sampling nodes, the voltage can be obtained in the order of terminal sampling node, load sampling node, and terminal sampling node. If the difference between the measured voltages of the two terminals is within the normal fluctuation range of the corresponding operating point, it indicates that the output state of the power supply under test has not changed beyond the normal fluctuation range between the two terminal samplings. The measured voltage of the load end obtained between the two terminal samplings can be correlated with the measured voltage of the corresponding terminal. If the difference between the measured voltages of the two terminals exceeds the normal fluctuation range of the corresponding operating point, the measured voltage of the load end in this test will not be used to form the link difference, and the voltage will be collected again after the current operating point re-enters the stable range.

[0101] When it is necessary to continuously observe the changes of the connection link and the power supply under test over time, the terminal sampling nodes and load sampling nodes can be continuously and alternately collected in a fixed order under stable working conditions. The node switching cycle should be greater than the sum of the action time of the channel selection component and the establishment time of the independent acquisition channel, and less than the main time scale of the temperature change of the connection link and the temperature change of the power supply under test that needs to be observed. The specific node switching cycle can be determined according to the datasheet of the channel selection component, the response time of the independent acquisition device, and the temperature rise change records obtained in advance.

[0102] When there is periodic power frequency interference at the testing station, the average sampling duration under stable operating conditions can be set as an integer multiple of the main interference period. For example, in a 50Hz or 60Hz power frequency environment, the average sampling duration can be selected as 200ms. The 50Hz power frequency period is 20ms, and 200ms corresponds to 10 complete power frequency periods. The 60Hz power frequency period is approximately 16.67ms, and 200ms corresponds to 12 complete power frequency periods. Therefore, using 200ms can cover the integer periods of the two common power frequency frequencies, reducing the impact of periodic power frequency interference on stable voltage measurement. When the main periodic interference frequency on site is different from 50Hz or 60Hz, the corresponding integer multiple can be selected as the average sampling duration according to the actual interference period.

[0103] If the measured terminal voltage, measured load voltage, or corresponding internal readback value is missing in a certain operating state, and the current operating state is still in a stable range, the current output voltage and load current remain unchanged and the missing data is re-acquired; if the operating state has changed and the original state cannot be restored, the corresponding operating state is re-established and data is collected, without generating key data for internal difference or link difference calculation through interpolation.

[0104] After the time is matched, a corresponding data record is generated for each valid working state. The data record includes at least the working state identifier, internal readback voltage, terminal measured voltage, load measured voltage, actual load current, internal readback value corresponding time, terminal sampling time, load sampling time, communication round trip time, and data validity status, which are used to generate comparable detection data under different load current, output voltage, and dwell time conditions.

[0105] Specifically, such as Figure 4 As shown: After completing the time correspondence of each sampling data, multiple detection working points are set according to the load current, output voltage and dwell time, and an unloading observation stage is set between some detection working points so that the voltage drop change generated by the connection link and the output change of the power supply under test can be manifested under different working conditions.

[0106] During load current changes, the output voltage of the power supply under test is kept constant or maintained at a predetermined test voltage, while the electronic load is controlled to change the load current in order from low to high. When the continuous output capability of the power supply under test and the load-bearing capacity of the electronic load both meet the testing requirements, multiple current operating points can be set, for example, at 10%, 25%, 50%, 75%, and 100% of the rated current. Among them, 10% of the rated current is used to form a low load state, 25% and 50% of the rated current are used to form a medium-low load and a medium load state, and 75% and 100% of the rated current are used to form a higher load state, thereby obtaining voltage data of the connection link as the load current changes within a wide load range.

[0107] The above current ratios can be adjusted according to the actual operating range of the power supply and electronic load under test; the minimum current operating point should not be lower than the minimum current that the electronic load can stably control, while ensuring that the current measurement channel can reliably distinguish the actual load current; the maximum current operating point should not be higher than the smaller of the allowable continuous output current of the power supply under test, the allowable input current of the electronic load, and the allowable current under the current heat dissipation conditions; the corresponding values ​​can be determined according to the product specifications of the power supply under test, the manual of the electronic load equipment, and the continuous load capacity of the testing station.

[0108] There should also be a sufficient current span between the lowest and highest current operating points so that the change in the link difference between the two operating points exceeds the normal fluctuation range of the link difference and can be stably distinguished by an independent acquisition channel. For example, when both the power supply under test and the electronic load allow a wide load range, the span between the lowest and highest current operating points can be selected as more than 60% of the rated current. When using this range, it should be confirmed through repeated measurements under a healthy connection state that the resulting change in the link difference can stably exceed the normal fluctuation range. If a smaller current span can already meet the above distinguishable condition, it is not required to reach 60% of the rated current.

[0109] After the electronic load is adjusted to the target current, the current output voltage and load current are maintained. Once the internal readback voltage, terminal measured voltage, load measured voltage, and actual load current enter the stable range of the corresponding operating point, the data of the current operating point is collected. The data from the previous stage after each current operating point enters the stable range can be used to compare the link difference under different load currents, so as to reduce the impact of continuous current carrying and temperature rise of the connection link on the comparison relationship between different current operating points.

[0110] If further observation of the impact of current-carrying temperature rise on the connection link is required, after completing the operation points from low to high current, the same operation points can be repeated in order from high to low, so that the same load current corresponds to the load increase process and the load decrease process after running under a higher load. By comparing the link difference obtained under the same load current, it can be determined whether the connection link changes under different load time conditions. When the detection cycle is limited, three current operation points of low, medium and high can also be selected, as long as the change in the link difference between adjacent operation points can exceed the normal fluctuation range of the link difference and can be reliably distinguished by the independent acquisition channel.

[0111] During the output voltage change process, the electronic load is kept at a stable operating current, and the output voltage of the power supply under test is changed. When the output range of the power supply under test meets the testing requirements, multiple voltage operating points can be set, for example, at 5%, 20%, 50%, 80%, and 100% of the rated voltage. Among them, 5% and 20% of the rated voltage are used to form a low output region, 50% of the rated voltage is used to form an intermediate output region, and 80% and 100% of the rated voltage are used to form a higher output region, so as to obtain the corresponding data of the internal readback voltage and the terminal measured voltage at different output amplitudes.

[0112] The lowest operating voltage point should not be lower than the lowest stable output voltage specified in the product specifications of the power supply under test. When the power supply under test cannot operate stably near 5% of its rated voltage, the lowest stable output voltage allowed by the product can be used as the lowest operating voltage point. The highest operating voltage point should simultaneously meet the requirements of the continuous output capability of the power supply under test and the allowable input power of the electronic load. When the rated voltage cannot be reached at 100% under the current load current, the highest stable output voltage that meets the power limitation conditions can be used. When the power supply under test has range switching or segmented control characteristics, voltage operating points can be added on both sides of the corresponding range switching position to check the relationship between different output ranges. The specific values ​​of each voltage operating point can be determined according to the product specifications of the power supply under test, the allowable power of the electronic load, and the actual test range.

[0113] For testing points that require separate observation of the operational status establishment process and continuous load changes, short dwell time and long dwell time can be set. The short dwell time can be selected as 5 to 15 seconds. This time should be greater than the time required for the power supply under test to complete output adjustment, the time required for the electronic load to complete load adjustment, and the time required for the independent acquisition channel to enter a stable state, so that the short dwell data is taken from the stable range. At the same time, the short dwell data acquisition should be completed before the power cable, connector, and test fixture experience a significant overall temperature rise. The specific time can be determined based on the dynamic response record of the power supply under test, the response time of the electronic load, and the repeated test results of the health test station.

[0114] Long dwell time can be selected, for example, from 120 to 300 seconds. The long dwell time should at least cover the main process from the start of the connection link heating up to the point where the link difference enters the normal fluctuation range of the corresponding operating point. When it is necessary to continue to observe the slow changes of the power supply under test over time, the current operating point should be maintained and data should be collected after the link difference enters the normal fluctuation range. The specific long dwell time can be determined based on the changes in the connection side temperature, the link difference, and the temperature of the power supply under test chassis over time. For example, if the connection link has entered a stable state within 120 seconds and the data of the power supply under test after the connection link has stabilized can be obtained, a dwell time close to 120 seconds can be used. For cases with high rated power, large heat capacity of power cables or test fixtures, or slow thermal changes of the power supply under test itself, a dwell time close to 300 seconds or longer can be used.

[0115] Data can be continuously collected at fixed time intervals during the dwell period; for example, the sampling interval can be selected from 0.5 to 2 seconds. The sampling interval should be greater than the time required for the independent acquisition channel to complete node switching, measurement and stabilization, and less than the main thermal change time scale to be observed, so as to ensure that multiple continuous data points can be obtained during a dwell period. The specific sampling interval can be determined according to the action time of the channel selection component, the response time of the independent acquisition device, the data storage capacity and the pre-obtained temperature rise change records.

[0116] Set an unloading observation phase between partial load operating points; when entering the unloading observation phase, keep the output voltage setting and output enable state of the power supply under test unchanged, and only reduce the electronic load current; when the power supply under test is allowed to run under no-load, the load current can be reduced to zero; when the power supply under test has a minimum load requirement, the load current is reduced to the lowest load level at which both the power supply under test and the electronic load can operate stably.

[0117] For example, if the electronic load can be stably controlled and the power supply under test allows for corresponding low-load operation, the load current can be selected to be no higher than 1% of the rated current. When using this current range, it should also be confirmed that the voltage drop of the connection link caused by the remaining load current does not exceed the normal fluctuation range of the link difference determined under no-load or minimum stable load conditions. For power supplies under test with large rated current, even if the remaining load current is less than 1% of the rated current, if the connection voltage drop caused by this current can still be stably distinguished by the independent acquisition channel, the load current should be further reduced. If it cannot be further reduced, the corresponding link difference should be interpreted according to the actual remaining load current, and this state should not be directly regarded as a completely no-load state.

[0118] The duration of the unloading observation phase can be selected, for example, from 3 to 10 seconds. This time should be greater than the time required for the electronic load to complete unloading, the time required for the output loop of the power supply under test to re-enter a stable state, and the time required to establish an independent acquisition channel, so that the sampling data in the unloading observation phase reflects the stable output state after unloading. At the same time, it should be less than the time for the connection link to undergo significant overall cooling after unloading, so as to preserve the thermal state of the connection link before entering the unloading observation phase as much as possible. The specific duration can be determined based on the electronic load unloading response record, the no-load or low-load stabilization time of the power supply under test, and the temperature drop record on the connection side.

[0119] After the unloading observation phase is completed, the electronic load is adjusted to the next test working point, and data acquisition continues after the corresponding output voltage and load current re-enter the stable range. If the power supply under test enters current limiting, over-temperature or other protection states during the adjustment of load current or output voltage, the corresponding test conditions are stopped and the test is returned to the previous working point that has been confirmed to be stable. If the power supply under test still cannot restore normal output after returning, the current test ends.

[0120] After testing under different load currents, output voltages, dwell times, and no-load conditions, data records are generated according to the testing operation status. The data records include at least the following fields: operating status identifier, load current, output voltage, dwell time, no-load status identifier, internal readback voltage, terminal measured voltage, load-side measured voltage, connection-side temperature, body-side temperature, corresponding sampling time, and data validity status. These fields are used to subsequently establish the difference relationship between the internal readback voltage and the terminal measured voltage, as well as the difference relationship between the terminal measured voltage and the load-side measured voltage.

[0121] Specifically, such as Figure 5 As shown: For valid detection data with established time correspondence, let the internal readback voltage be... The actual measured voltage at the terminal is The measured voltage at the load end is The internal difference is determined based on the internal readback voltage and the actual measured voltage at the terminals. The formula is determined as follows:

[0122]

[0123] Then, the link difference is determined based on the measured voltage at the terminal and the measured voltage at the load. The formula is determined as follows:

[0124]

[0125] Among them, the internal difference is used to represent the deviation between the internal readback voltage of the power supply under test and the actual measured voltage at the terminal; the link difference is used to represent the voltage difference between the terminal sampling node and the load sampling node formed by the power cable, connector, test fixture and corresponding connection parts; by analyzing the internal difference and the link difference respectively, it is possible to avoid directly attributing all voltage deviations measured at the load end to the power supply under test.

[0126] For the connection link, firstly, the link difference under different load currents is used to analyze its variation with current. Front-end data after different current operating points enter the stable range can be selected to make the temperature state of the connection link between different operating points as close as possible. For two operating points with load currents I1 and I2, the change in the link difference between the two operating points is calculated and divided by the corresponding change in load current to obtain the equivalent resistance of the connection in this current range. Using two adjacent current operating points to calculate the equivalent resistance of the connection can reduce the influence of the fixed offset in the link difference that is unrelated to the load current on the calculation results.

[0127] The equivalent resistance of the connection is used to represent the voltage drop caused by a unit current change in the current range of the current connection. It does not mean that the connection has a constant resistance value under all load current and temperature conditions. In specific analysis, the change in load current should be sufficient to make the change in the corresponding link difference exceed the normal fluctuation range of the link difference, and can be stably distinguished by an independent acquisition channel. Otherwise, this set of data will not be used to calculate the equivalent resistance of the connection.

[0128] When there are three or more operating points with different load currents, the equivalent resistance of the connection between adjacent current ranges can be calculated separately, and the changes between different current ranges can be compared. Three or more current operating points are used because at least two adjacent current ranges need to be formed to determine whether the voltage drop per unit current changes with the load current. When the difference between the equivalent resistance of the connection between different current ranges is within the range of normal fluctuation of the link difference, it indicates that the connection link mainly exhibits a stable ohmic voltage drop within the current detection range. When the equivalent resistance of the connection in a certain current range continuously deviates from other current ranges, and the corresponding link difference changes beyond the normal fluctuation range, and still exists after re-acquisition, it is recorded that there is a nonlinear change in the connection link in that current range, and further judgment is made by combining the measurement data, temperature data, and continuous load data under no-load or minimum stable load conditions.

[0129] The link difference obtained during the unloading observation phase or under the lowest stable load condition is used to verify the connection voltage drop caused by the load current. When the load current drops to zero or close to zero, the ohmic voltage drop directly caused by the load current should decrease accordingly. Therefore, the link difference obtained during the unloading observation phase can be compared with the link difference at the normal load operating point to distinguish the voltage drop that varies with the load current and the voltage difference that still exists under low load conditions.

[0130] When the link difference during the unloading observation phase is within the normal fluctuation range of the corresponding operating state, and the link difference increases with the increase of load current after being loaded, it can be confirmed that the main voltage drop of the connection link is related to the load current. When the link difference during the unloading observation phase still exceeds the normal fluctuation range of the corresponding operating state, this part is not directly attributed to the deviation of the tested power supply body, but the test result is retained for further inspection of sampling nodes, measurement polarity, channel selection components, connectors, test fixtures, and remote sensing connection status.

[0131] For changes in the connection link over time, compare the link difference at different time points during a long dwell period with the same load current. The link difference obtained earlier after entering the stable range can be compared with the link difference obtained later in the dwell period. When the difference between the two is within the normal fluctuation range of the link difference, it is considered that the connection link has not shown a stable and identifiable continuous change during the current detection period. When the link difference changes continuously with the dwell time and the cumulative change exceeds the normal fluctuation range of the link difference, it is recorded as a change in the connection link over time.

[0132] When using a load current detection method that proceeds from low to high and then from high to low, the link difference obtained during the load increase and decrease processes can be compared. If the difference between the two link differences under the same load current exceeds the normal fluctuation range and still exists after re-collection, it indicates that the load current is the same but the load time or temperature state of the connection link is different. The corresponding difference can be used as data for subsequent judgment of the influence of the connection link temperature.

[0133] For the deviation of the tested power supply, the main analysis focuses on the relationship between the internal difference and the output voltage and residence time.

[0134] When comparing internal differences under different output voltages, low output voltage and high output voltage operating points can be selected first. If the internal differences remain similar under multiple low output voltage operating points, and the changes in internal differences between different operating points are within the normal fluctuation range of internal differences, then this part is recorded as a fixed deviation of the power supply under test. The fixed deviation indicates that there is a deviation between the internal readback voltage and the terminal measured voltage that is basically not synchronized with the current output voltage.

[0135] If the internal difference changes repeatably as the output voltage increases, and the change in the internal difference between different output voltage operating points exceeds the normal fluctuation range of the internal difference, then the measured power supply body has a proportional deviation related to the output voltage. The proportional deviation can be characterized by the relationship between the change in the internal difference between the low output voltage operating point and the high output voltage operating point and the change in the output voltage, and is used to determine whether the deviation between the internal readback voltage and the terminal measured voltage changes with the output amplitude.

[0136] To check for local variations between low and high output voltages, one or more intermediate voltage operating points can be set between them. The overall trend is determined based on the internal difference between the low and high output voltage operating points, and then the internal difference of the intermediate voltage operating points is compared with this trend. When the internal difference of the intermediate voltage operating points is within the normal fluctuation range, it is considered that there is no stably identifiable local deviation in the current intermediate output region. When the intermediate voltage operating points continuously deviate from this trend, the deviation exceeds the normal fluctuation range of the internal difference, and the deviation still exists after re-acquisition, it is recorded that there is a segmented deviation in the corresponding output voltage region.

[0137] Setting at least one intermediate voltage operating point allows the low output voltage, high output voltage, and intermediate output voltage to form three or more different output states, thereby determining whether the change in internal difference is only manifested as an overall fixed offset or a proportional change, or whether there is a local change that only appears in some output areas; the specific number of intermediate voltage operating points is determined based on the output range of the power supply under test, whether there is range switching, and the detection time, and it is not required that different models of power supplies under test use the same number.

[0138] For the deviation of the power supply under test with load time, the internal difference and link difference are observed simultaneously during the long residence period. When the link difference has entered the normal fluctuation range of the corresponding operating point, while the internal difference continues to change in the same direction and the cumulative change exceeds the normal fluctuation range of the internal difference, the slow deviation of the power supply under test with running time is recorded. The source of this slow deviation is then further determined by combining the load current change, the unloading observation stage, and the temperature change at different locations.

[0139] The aforementioned fixed deviation, proportional deviation, segmented deviation, and slowly varying deviation are all used to describe the deviation relationship between the internal readback voltage and the terminal measured voltage that can be observed through the current detection method. Since no single component in the reference source, setting channel, or readback channel inside the power supply under test is directly measured during the detection process, the absolute error of a certain internal component is not directly determined based on the above deviations.

[0140] When the internal readback value cannot be obtained normally, the internal difference is not calculated. Only the link difference is formed by the measured voltage at the terminal and the measured voltage at the load end, and the connection link analysis continues. When some load current operating points or output voltage operating points lack valid data, if the remaining data still includes at least two load current states or two output voltage states with distinguishable differences, the basic direction of change of the corresponding difference can be determined, and the current data is recorded as incomplete. When the remaining data is insufficient to form two comparable operating states, the missing detection operating states are re-established and supplemented with data. Interpolated data is not used to replace key measured data.

[0141] The above processing generates a deviation analysis record. The deviation analysis record includes at least the following fields: operating status identifier, load current, output voltage, dwell time, internal difference, link difference, connection equivalent resistance, nonlinear change of connection link, change of connection link with load time, fixed deviation of the tested power supply body, proportional deviation, segmented deviation, slow-varying deviation, corresponding sampling time, connection side temperature, body side temperature, and data validity status. These fields are used to determine the source of slow-varying deviation by combining time changes, load current changes, and temperature changes at different locations, and to judge the connection status and the status of the tested power supply body.

[0142] Specifically, such as Figure 6 As shown: For deviations that change with load time, the main source is determined by combining the time of change, the relationship between current change and temperature change at different locations; the data used include link difference, internal difference, actual load current, measurement results under no-load or minimum stable load conditions, connection side temperature and body side temperature.

[0143] Regarding the time variation, if the link difference continuously changes in the early stage after the load is established, and then gradually enters the normal fluctuation range of the link difference, while the internal difference does not show synchronous changes exceeding the normal fluctuation range, it indicates that the change mainly occurs in the connection link; if the link difference has entered the normal fluctuation range, but the internal difference continues to change in the same direction with the load time, and the cumulative change exceeds the normal fluctuation range of the internal difference, it indicates that the slow variation deviation is mainly related to the tested power supply itself.

[0144] The preceding and following segments in the above judgment are not divided using a uniform fixed time, but are determined based on the actual measured changes in the link difference at the corresponding working point; the time from the start of load on the link to before the link difference enters the normal fluctuation range can be regarded as the main change period of the link; the continuous sampling period after the link difference enters the normal fluctuation range can be regarded as the subsequent observation period; thus, it can adapt to the response time differences caused by different power levels, different cable specifications and different test fixture heat capacities.

[0145] Regarding current changes, the link difference is compared at different load current operating points and under no-load or minimum stable load conditions. If the link difference increases with increasing load current and decreases with decreasing load current, and the corresponding link difference decreases significantly to within the normal fluctuation range under no-load or minimum stable load conditions, it indicates that this part of the change has a strong correlation with the current-carrying voltage drop of the connection link.

[0146] If the internal difference does not diminish synchronously during the load current reduction, maintains its original trend after a short load reduction, and continues to change in the original direction after the load is restored, while the link difference does not show a corresponding change that can explain this change, it indicates that the slow-changing deviation is more likely to originate from the power supply under test itself. For power supplies under test that cannot enter a completely unloaded state, use the lowest stable load allowed by the product, and determine the corresponding link voltage drop according to the actual remaining load current, without directly equating the lowest stable load state with the absolute unloaded state.

[0147] Regarding temperature changes, the connection-side temperature and the body-side temperature are correlated with the time changes of the link difference and internal difference, respectively. If the connection-side temperature near the power cable, connector, or test fixture changes continuously, and the link difference changes accordingly within a similar time frame, while the body-side temperature does not show a significant change that can explain the internal difference change, it indicates that the corresponding slow change is mainly related to the temperature rise of the connection link. If the connection-side temperature and the link difference have reached a stable state, but the body-side temperature continues to change, and the internal difference shows a corresponding change exceeding the normal fluctuation range, it indicates that the corresponding slow change is mainly related to the thermal state of the power supply under test.

[0148] Temperature data is used to determine the location and time relationship of deviation changes, and a uniform fixed temperature unrelated to the tested object is not used as the criterion for the source of deviation; the allowable operating temperatures of the connection side and the body side are determined according to the product specifications or testing requirements of the power cable, connector, test fixture and the power supply under test, respectively.

[0149] The reliability of attribution for slow-varying deviations is determined by combining the results of time variation, current variation, and temperature variation. When all three results point to the connection link or the power supply under test, the reliability is determined to be high. When one aspect of the data is missing, or the judgment result of one aspect is inconsistent with the other two aspects, the reliability is determined to be medium, and the missing or inconsistent data is recorded. When the judgment results of two or more aspects point to different sources, or the existing data cannot establish a correspondence between time, current, and temperature, the reliability is determined to be low, and data under the corresponding operating conditions is obtained again.

[0150] When the temperature sensor is not working properly, the preset temperature or temperature at other locations is not used to replace the actual measurement results. Instead, the source of slow deviation is determined based on the changes in time and current. In this case, the high attribution confidence is not determined based on the condition that the data in terms of time, current and temperature are all complete. When the power supply under test is not allowed to enter the no-load state, the current correlation can be determined based on the changes in the link difference corresponding to the same load current during the load increase and decrease process. The lowest stable load state and the actual load current are saved in the detection record.

[0151] After determining the source of slow deviation, first determine the connection status, and then determine the status of the power supply under test; the connection status includes connection integrity and connection health.

[0152] Connection integrity is mainly judged based on sampling nodes, voltage relationships, and data under low load conditions. When the measurement polarity of the terminal sampling node and the load sampling node is consistent with the actual output polarity of the power supply under test, the relationship between the two sampling nodes and the corresponding output channels is correct, the necessary sampling nodes can obtain data normally, and the sensing sampling node is consistent with the actual sensing position when the remote sensing function is enabled, the sampling relationship is confirmed to meet the connection integrity check requirements.

[0153] If the link difference under no-load or minimum stable load conditions exceeds the normal fluctuation range of the link difference corresponding to that condition, or if there are errors such as measurement polarity, incorrect correspondence between sampling nodes and output channels, incorrect position of sensing sampling nodes, or continuous lack of valid data from necessary sampling nodes, then suspend the testing of the power supply under test and check the power cables, connectors, test fixtures, measurement leads, and channel selection components. After completing the re-tightening, replacement, or adjustment, recheck the correspondence of sampling nodes and obtain test data again. Do not continue to use the load time data generated before the connection adjustment.

[0154] After the connection integrity requirements are met, the connection health status is judged based on the allowable voltage drop of the connection link. The allowable voltage drop of the connection link is determined primarily based on the test specifications of the power supply under test, the design requirements of the power cable and connector, the design requirements of the test fixture, or the verified test operation documents. If the above documents directly specify the allowable voltage drop of the connection link, the corresponding specification shall be adopted. If not directly specified, the allowable voltage drop under the corresponding operating current can be determined by combining the power cable resistance, connector contact resistance, test fixture conductive path resistance, and repeated measurement results of the healthy workstation.

[0155] Based on the allowable voltage drop and the corresponding load current, the permissible range of the equivalent resistance of the connection can be determined. For example, if a certain model of the power supply under test or the corresponding testing work document clearly stipulates that the maximum voltage drop that the connection link can withstand under the current rated operating conditions is 2% of the output voltage, the connection health limit can be determined according to this 2% voltage drop and the corresponding load current. The 2% only applies to objects supported by corresponding product documents or testing documents and is not a fixed ratio used by different models of programmable power supplies. For precision programmable power supplies with output accuracy requirements significantly less than 2%, the smaller permissible connection voltage drop specified in the product should be used.

[0156] When the actual link difference or the equivalent resistance of the connection determined by different load current data exceeds the corresponding connection health limit, record the connection link abnormality, and prioritize checking the power cable, connector and test fixture. Do not directly regard the load terminal voltage deviation in this state as an abnormality of the power supply under test.

[0157] For testing stations that have been used for a long time, historical reference values ​​of the equivalent resistance of the connection can be established based on historical testing data that have confirmed that the connection is normal. The data used to establish the historical reference values ​​should come from the test results of complete connection, connection health status meeting requirements, valid sampling data and test fixture not being under maintenance or adjustment. Data under abnormal connection status is not used to update the historical reference values.

[0158] The normal range of historical reference values ​​is determined based on the dispersion of multiple consecutive tests conducted by the same test fixture in a healthy state. The observation range and warning range can be further determined by combining the test results before and after fixture maintenance, as well as the changes under confirmed abnormal connection conditions. For example, if historical data from the same workstation can prove that a change within 10% of the historical reference value is a normal change under a healthy connection condition, a change between 10% and 20% exceeds the normal historical range but has not yet reached the connection health limit, and a change exceeding 20% ​​corresponds to confirmed loose connectors, fixture wear, or other connection deterioration conditions, then the range within 10% can be used as the historical reference value update range, 10% to 20% as the observation range, and the range exceeding 20% ​​as the warning range.

[0159] The aforementioned 10% and 20% are only used when the corresponding testing station already has healthy samples, maintenance records, and abnormal connection data that can support the corresponding range. If the existing historical data cannot prove that the above range is applicable to the current station, the corresponding range shall be re-determined based on the actual discrete range under the normal connection state of the current station and the changes in the confirmed abnormal connection state, and 10% and 20% shall not be directly used.

[0160] When the current equivalent resistance of the connection is within the historical reference value update range, the current result can be used for subsequent historical reference value updates; when it is within the observation range, the current test result is saved but the historical reference value is not updated; when it exceeds the warning range or the connection health limit, a connection check is performed; when multiple consecutive test objects show that the equivalent resistance of the connection deviates from the historical reference value in the same direction, the test fixture and connection link are checked first to avoid incorrectly classifying the changes of the test station itself into multiple tested power supplies.

[0161] After the connection status meets the requirements, check whether the current test data can support the judgment of the power supply under test. The data used for the judgment of the power supply should meet the following requirements: the internal readback value and the external measured value can establish a time correspondence; the key load current and output voltage operating status have valid data; the internal readback status meets the current judgment requirements; and the internal difference and the link difference can form a stable change relationship after repeated acquisition.

[0162] When the reliability of the slow deviation attribution is high and other test data are complete, the current data can be used directly to determine the status of the power supply under test. When the reliability of the attribution is medium or there is a missing data item, but the remaining data can still form a comparable relationship, the corresponding data should be obtained again before making a judgment. When the time correspondence cannot be established, the key working status lacks effective data, or multiple test results are contradictory, no final judgment result for the power supply under test will be formed.

[0163] During retesting, the corresponding data is reacquired based on the abnormal content; when the time correspondence is abnormal, the time correspondence between the internal readback value and the measured voltage at the terminal and the measured voltage at the load end is re-established; when the load current, output voltage, or dwell data is insufficient, the corresponding detection working state is re-established; when the sampling node or connection relationship is abnormal, the connection is re-checked; when the internal difference or link difference cannot repeat the same change relationship, the data is re-acquired under the same detection conditions; when continuous retesting still cannot form a consistent result, the existing original detection data is saved and manually reviewed.

[0164] Only when the connection integrity and connection health status meet the requirements, and the current test data can support the judgment of the power supply under test, the fixed deviation, proportional deviation, segmented deviation and slow-changing deviation of the power supply under test are used to judge the status of the power supply under test. The allowable range of each deviation is determined according to the output accuracy, output stability and corresponding test operation documents specified in the product specification of the current model of the power supply under test. A uniform fixed value is not used to replace the product requirements of different models of the power supply under test.

[0165] When the fixed deviation, proportional deviation, segmented deviation, and slowly varying deviation are all within their respective allowable ranges, record that the tested power supply meets the requirements under the current testing conditions; when a certain deviation exceeds the allowable range of the corresponding product, and the corresponding test data is complete and the source of the deviation can be determined, record the corresponding abnormal item; when the test result is near the boundary of the product's allowable range or the data still needs to be verified, retest or perform manual verification.

[0166] If the internal readback value cannot be obtained normally, but the measured voltage at the terminal and the measured voltage at the load can be obtained normally, the connection link detection result can still be formed, and the actual output status of the power supply under test can be checked according to the output setting value and the measured voltage at the terminal. However, a complete body deviation analysis result that depends on the internal readback voltage is not formed.

[0167] If the output is shut down, power supply is interrupted, emergency stop occurs, or power connection is reconnected during the test, the thermal continuity of the connection link and the power supply under test has changed. Therefore, the data on the change with load time generated before the interruption is not used continuously with the data after the recovery. After the test is resumed, the sampling node and power connection are rechecked, and the load current, output voltage, dwell time and temperature data are obtained again from the new stable working state.

[0168] After completing the above judgment, a current test result record is generated; the test result record includes at least the following fields: the identifier of the object under test, the connection integrity status, the connection equivalent resistance, the connection health status, the historical reference value comparison result, the fixed deviation of the power supply under test, the proportional deviation, the segmented deviation, the slow-varying deviation, the source of the slow-varying deviation, the attribution confidence, the test data status, the anomaly handling result, and the final test status.

[0169] By using the above detection method, the voltage drop generated by the connection link and the deviation of the power supply under test are judged separately. The state of the power supply under test is judged only after the connection status meets the requirements. This reduces the impact of the contact resistance and current-carrying temperature rise of power cables, connectors and test fixtures on the test results of the power supply under test, and provides corresponding measurement data and judgment basis for abnormal locations.

[0170] Example 2: Figure 7 The present invention discloses a programmable power supply detection system, comprising:

[0171] Sampling and acquisition module: used to set sampling nodes at the output end of the power supply under test and the load input end, and to collect the voltage of the two nodes in a time-division manner by the same independent acquisition channel, and to obtain the internal readback value of the power supply under test;

[0172] Time correspondence module: used to establish the time correspondence between the internal readback value and the voltage of the two nodes;

[0173] Operating status control module: used to sequentially change the load current, output voltage and dwell time and collect the corresponding data, as well as set an unloading observation phase between partial load operating states;

[0174] Deviation Analysis Module: Used to determine the deviation of the power supply under test and the external connection deviation based on the relationship between the internal readout value and the change of the output node voltage, as well as the relationship between the changes of the voltages of the two nodes.

[0175] The detection and judgment module is used to determine the source of slow deviation by combining the relationship between the deviation and the change of load current and the temperature at the corresponding location, and to make a status judgment on the power supply under test that meets the detection conditions after verifying the external connection status.

[0176] Example 3: Based on Examples 1 and 2, the specific application process of a programmable power supply detection method and system is further explained:

[0177] In a specific application, the programmable DC power supply to be tested is placed at the testing station and connected to the electronic load via power cables, connectors, and test fixtures. After the testing system is started, the sampling acquisition module reads the model, rated voltage, rated current, and output channel information of the power supply under test, and determines the terminal sampling node and load sampling node based on the current output channel. The terminal sampling node and load sampling node are respectively connected to the same independent acquisition channel through measurement leads. The connection-side temperature sensor is placed near the connector or test fixture, and the body-side temperature sensor is placed on the casing of the power supply under test.

[0178] After the testing connection is completed, the sampling acquisition module controls the independent acquisition channel to sequentially acquire the measured voltage of the terminals and the measured voltage of the load, and reads the internal readback voltage of the power supply under test through the communication interface. When the power supply under test is allowed to run under no-load, the working status control module adjusts the electronic load to the no-load state. When the power supply under test has a minimum load requirement, the electronic load is adjusted to the minimum stable load state allowed by the product. In this state, the measurement polarity, output channel and acquisition range of the two sampling nodes are checked. If the sampling node is incorrect or the acquired data exceeds the current range, the subsequent load test is paused, and the acquisition is restarted after the sampling node or acquisition range adjustment is completed.

[0179] After the connection verification is completed, the time correspondence module uses the local clock of the detection and control equipment as a unified time reference to record the corresponding time of the internal readback value, the measured terminal voltage, and the measured load voltage. When the power supply under test cannot provide a valid timestamp, the module records the sending time of the internal readback request and the response return time. If the corresponding time range does not cross the beginning or end of the load current adjustment, output voltage adjustment, or unloading observation phase, the module establishes a correspondence between the internal readback value and the measured terminal voltage and the measured load voltage obtained within the same stable interval. Data that cannot establish a reliable time correspondence will not be used for subsequent deviation analysis.

[0180] The operating status control module sets multiple load current operating states based on the continuous output capability of the power supply under test and the carrying capacity of the electronic load. For example, if the corresponding equipment allows, 10%, 25%, 50%, 75%, and 100% of the rated current can be used for testing. The above current ratios are determined according to the product specifications of the power supply under test, the manual of the electronic load equipment, and the continuous load carrying capacity of the testing station, and can be adjusted according to the actual allowable operating range. After each change in load current, the current output voltage and load current are kept constant. After the measured voltage at the terminals, the measured voltage at the load end, and the actual load current enter the stable range, the sampling and acquisition module collects the corresponding data.

[0181] After completing the load current detection from low to high, the same load current can be repeated in order from high to low to compare the link difference of the same load current under different load times. An unloading observation phase is set between the partial load working states. The output voltage setting and output enable state of the power supply under test are kept unchanged, the electronic load is reduced to the no-load state or the lowest stable load state, and the corresponding data is collected after the power supply under test re-enters the stable range.

[0182] In output voltage variation detection, the electronic load is kept at a stable operating current, and the output voltage is varied within the allowable output range of the power supply under test. For example, when operating conditions permit, different output voltages can be set to 5%, 20%, 50%, 80%, and 100% of the rated voltage. When the power supply under test cannot output stably near 5% of the rated voltage, the lowest stable output voltage allowed by the product is used. When the rated voltage cannot be reached at 100% due to the continuous output capability of the power supply under test or the allowable power of the electronic load, the highest stable output voltage allowed under the current load conditions is used.

[0183] The deviation analysis module determines the internal difference and link difference based on the internal readback voltage, terminal measured voltage, and load measured voltage obtained within the same stable range. The link difference increases with the increase of load current and decreases significantly with the decrease of load current during the unloading observation phase. The corresponding change is used as the basis for judging the current-carrying voltage drop of the connection link. It can also determine the equivalent resistance of the connection based on the changes in the link difference corresponding to different load currents, which is used to analyze the connection status of power cables, connectors, and test fixtures.

[0184] For the power supply under test, the deviation analysis module compares the internal differences under different output voltages and different dwell times. When the internal difference is mainly manifested as a deviation that does not change with the output voltage, a repeatable change with the output voltage, a significant change only in some output areas, or a change with the continuous load time, it forms fixed deviation, proportional deviation, segmented deviation, and slowly changing deviation records respectively.

[0185] During continuous load operation, the sampling module simultaneously acquires the connection-side temperature and the body-side temperature. The detection and judgment module compares the temperature data with the link difference, internal difference, and actual load current at corresponding times. When the link difference changes with the load current and connection-side temperature and decreases significantly during the unloading observation phase, while the internal difference remains within the normal fluctuation range, it is determined that the corresponding change mainly comes from the connection link. When the link difference has entered the normal fluctuation range, but the internal difference continues to change with the body-side temperature, it is determined that the corresponding slow deviation is mainly related to the tested power supply body.

[0186] After determining the source of the deviation, the detection and judgment module first verifies the integrity and health status of the connection. If the actual link difference or the equivalent resistance of the connection exceeds the corresponding allowable range, the connection link is recorded as abnormal, and the judgment of the status of the power supply under test is suspended. The allowable range of the connection link is determined according to the test specifications of the power supply under test, the design requirements of the power cable and connector, the design requirements of the test fixture, or the test operation document. After the connector is re-tightened, the test fixture is replaced, or the power connection is adjusted, the corresponding relationship of the sampling nodes is re-verified and the test data is collected again.

[0187] Only when the connection integrity and connection health status meet the requirements, the key operating status data are complete, and the internal readback values ​​and external measured values ​​can establish a valid time correspondence, the detection and judgment module judges the status of the power supply under test based on fixed deviation, proportional deviation, segmented deviation, and slowly varying deviation; the allowable range of each deviation is determined according to the output accuracy, output stability, or corresponding test operation documents specified in the current model of the power supply under test product specification.

[0188] If the internal readback interface cannot obtain data normally, but the terminal sampling node and load sampling node can still collect data normally, the system continues to analyze the link difference and equivalent resistance of the connection based on the measured voltage of the terminal and the measured voltage of the load, but does not form a complete body deviation judgment that relies on the internal readback value. If the output is shut down, emergency stop, power supply interruption or power connection is reinstalled during the detection process, the temperature change and slow deviation data formed before the interruption will not be used. Data will be collected again after the stable working state is re-established.

[0189] After the test is completed, a test result record is generated for the current power supply under test. The test result record includes at least the following fields: test object identifier, connection integrity status, connection equivalent resistance, connection health status, fixed deviation, proportional deviation, segmented deviation, slow deviation, source of slow deviation, test data status, and final test status.

[0190] It should be noted that this invention can be deployed on the device itself to realize embedded applications, or it can run on a PC or other terminal with a user interface, thereby meeting various hardware environments and usage requirements.

[0191] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented in software, the above embodiments can be implemented in whole or in part by a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions of the embodiments of this application are implemented in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted wirelessly or wiredly from one website, computer, server, or data center to another website, computer, server, or data center. Wired methods include optical fiber, twisted pair, coaxial cable, etc. Wireless methods include infrared, microwave, etc. Available media include any available media that can be accessed by a computer or data storage devices such as servers and data centers that contain one or more sets of available media. Available media can be magnetic media (floppy disks, hard disks, magnetic tapes), optical media (DVDs), or semiconductor media. Semiconductor media can be solid-state drives.

[0192] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0193] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A programmable power supply detection method, characterized in that, include: Sampling nodes are set at the output end of the power supply under test and the load input end. The voltage of the two nodes is collected in time by the same independent acquisition channel, and the internal readback value of the power supply under test is obtained. Establish the time correspondence between the internal readback value and the voltage of the two nodes; The load current, output voltage, and dwell time are changed sequentially to collect corresponding data, and an unloading observation phase is set. Based on the relationship between the internal readout value and the output node voltage, as well as the relationship between the voltage changes of the two nodes, the deviation of the power supply under test and the external connection deviation are distinguished respectively. By combining the relationship between each deviation and the changes in time, load current and corresponding location temperature, the source of slow deviation is determined. First, the external connection status is verified, and then the power supply under test that meets the testing conditions is judged.

2. The programmable power supply detection method according to claim 1, characterized in that, Sampling nodes are set at the output terminal of the power supply under test and the load input terminal. The voltages of the two nodes are collected in a time-division manner by the same independent acquisition channel, including: The terminal sampling node set at the output end of the power supply under test and the load sampling node set at the load input end are respectively connected to the same independent acquisition channel through measurement leads that do not carry power current. The independent acquisition channel switches between terminal sampling nodes and load sampling nodes through a channel selection component, and acquires the voltage of the corresponding nodes in sequence; When the power supply under test has multiple independent outputs, each output channel is set with a corresponding terminal sampling node and load sampling node. When the power supply under test enables the remote sensing function, a sensing sampling node is set at the actual access location of the remote sensing line, and the voltage at that location is collected through the independent acquisition channel.

3. The programmable power supply detection method according to claim 1, characterized in that, Obtain the internal readback values ​​of the power supply under test, including: Read the internal readback voltage through the communication interface of the power supply under test; when the power supply under test provides the internal readback current, read the internal readback current. Before load testing, check the measurement polarity, output channel, and acquisition range under no-load or minimum stable load conditions; When the sampled value reaches the upper limit of the current range or the acquisition device generates an over-range state, it switches to a higher range; When the internal readback value is unavailable, record the internal readback anomaly and retain the actual measured voltage at the terminal and the actual measured voltage at the load terminal.

4. The programmable power supply detection method according to claim 1, characterized in that, Establish the time correspondence between the internal readback value and the voltage of the two nodes, including: The detection control equipment records the corresponding time of the detection data using a local clock; The corresponding time of the internal readback value is determined based on the timestamp of the internal readback data, the trigger time, the latch time, or the time when the readback request is sent and the time when the response is returned. The actual measured voltage at the terminal and the actual measured voltage at the load terminal are recorded according to the actual sampling time. When the corresponding time points are in the same stable range, they form the same set of detection data. When the communication response fluctuates, the data is repeatedly read back within the stable range and data that crosses the working state switch is removed.

5. The programmable power supply detection method according to claim 1, characterized in that, The load current, output voltage, and dwell time are changed sequentially, and corresponding data are collected, including: Keep the output voltage of the power supply under test constant, set multiple load current operating states in order from low to high, and repeat some load current operating states in order from high to low as needed for testing. Maintain stable load current and set multiple output voltage operating states; The load current and output voltage for each operating state are determined based on the allowable operating range of the power supply and electronic load under test. Once each working state enters a stable range, corresponding data is collected according to either short or long dwell time.

6. The programmable power supply detection method according to claim 1, characterized in that, Set up an uninstallation observation phase, including: Between partial load operation states, keep the output voltage setting and output enable state of the power supply under test unchanged, and adjust the electronic load to no-load state or minimum stable load state. Data is collected after the power supply and electronic load under test enter the corresponding stable range. After completing the unloading observation, adjust the electronic load to the next load-bearing working state; When the power supply under test experiences current limiting, over-temperature, or other protection conditions, the current adjustment is stopped and the system returns to the previous stable operating state.

7. The programmable power supply detection method according to claim 1, characterized in that, Based on the relationship between the internal readback value and the output node voltage, as well as the relationship between the voltage changes of the two nodes, the deviation of the power supply under test and the external connection deviation are distinguished, including: The internal difference is determined by comparing the internal readback voltage with the actual measured voltage at the terminal, and the link difference is determined by comparing the actual measured voltage at the terminal with the actual measured voltage at the load end. The equivalent resistance of the connection is determined based on the change of the link difference under different load currents, and the link difference is compared under no-load or minimum stable load conditions, load increase process, load decrease process, and different dwell times. Based on the internal differences at low, intermediate, and high output voltages, we analyze fixed deviation, proportional deviation, and segmented deviation, and analyze the slow-varying deviation based on the internal differences at different residence times.

8. The programmable power supply detection method according to claim 1, characterized in that, By combining the relationships between various deviations and changes in time, load current, and corresponding location temperature, the sources of slow-varying deviations are determined, including: The link difference and internal difference are respectively mapped to the load time and load current, and the link difference is mapped to the connection side temperature and the internal difference is mapped to the body side temperature. By combining data obtained under no-load or minimum stable load conditions, as well as during load increase and decrease, the changes of link difference and internal difference with time, load current and corresponding location temperature are compared. The confidence level of attribution for slow-varying bias is determined based on the degree of consistency among the comparison results. When temperature data is unavailable, the judgment is made based on the changes over time and load current.

9. The programmable power supply detection method according to claim 1, characterized in that, First, verify the external connection status, then determine the power supply under test that meets the testing conditions, including: Verify connection integrity based on the corresponding relationship of sampling nodes, measurement polarity, and link difference under no-load or minimum stable load conditions; Verify the connection health status based on the allowable connection voltage drop, connection equivalent resistance, and historical reference values ​​of connection equivalent resistance; After the connection integrity and connection health status meet the requirements, check the time correspondence, the data of key load current and output voltage operating status, and the internal readback status. The state of the power supply under test is determined by fixed deviation, proportional deviation, segmented deviation, and slowly varying deviation.

10. A programmable power supply detection system for implementing the programmable power supply detection method according to any one of claims 1-9, characterized in that, include: Sampling and acquisition module: used to set sampling nodes at the output end of the power supply under test and the load input end, and to collect the voltage of the two nodes in a time-division manner by the same independent acquisition channel, and to obtain the internal readback value of the power supply under test; Time correspondence module: used to establish the time correspondence between the internal readback value and the voltage of the two nodes; Operating status control module: used to sequentially change the load current, output voltage and dwell time and collect the corresponding data, as well as set an unloading observation phase between partial load operating states; Deviation Analysis Module: Used to determine the deviation of the power supply under test and the external connection deviation based on the relationship between the internal readout value and the change of the output node voltage, as well as the relationship between the changes of the voltages of the two nodes. The detection and judgment module is used to determine the source of slow deviation by combining the relationship between the deviation and the change of load current and the temperature at the corresponding location, and to make a status judgment on the power supply under test that meets the detection conditions after verifying the external connection status.

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