Electronic load test system
By setting the first electronic load, the second electronic load and the control module in the electronic load test system, it is ensured that the change in the total load current of the switching power supply is consistent with the change in the input signal, and the problem of the inductance of the test cable distribution in the prior art affecting the detection results, and the accuracy of high dynamic performance detection is achieved.
Patent Information
- Application Number
- CN202411993330.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-03-14
AI Technical Summary
When the existing electronic load testing system detects the dynamic response of the switching power supply, the distributed inductance in the test cable affects the detection results, resulting in large errors and cannot meet the needs of high dynamic performance detection.
An electronic load testing system including a test cable, a first electronic load, a second electronic load and a control module are adopted. The control module is connected to the first electronic load and the second electronic load respectively, and inputs the associated input signal, so that the first electronic load and the second electronic load output current are ensured that the total load current change of the switching power supply is consistent with the input signal change, thereby eliminating the influence of the distributed inductance.
It effectively eliminates the impact of distributed inductors in the test cable on detection, improves detection accuracy, and meets the performance testing requirements of switching power supplies for dynamic high-speed response.
Smart Images
Figure CN119619902A_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to the technical field of electronic loads, and in particular to an electronic load testing system. [Background technology]
[0002] In the field of electronics and electrical appliances, switching power supplies are mainly used to provide a constant DC voltage (such as 5V). In life, the adapters used to charge common mobile phones, tablets, laptops and other household appliances are switching power supplies. Correspondingly, mobile phones, tablets, laptops and other household appliances are loads that consume electricity. For switching power supplies, voltage stability is a very important performance indicator. During the research and development and manufacturing process, it is necessary to detect the static stability and dynamic response of the switching power supply. Among them, the detection of dynamic response must be carried out when the current consumed at the load end changes rapidly, so as to observe whether the voltage output by the switching power supply is stable.
[0003] Since the switching power supply is not directly connected to household devices such as mobile phones, tablets or notebooks during the research and development and manufacturing process, the existing technology is to perform dynamic performance testing on the switching power supply by simulating electronic devices to set electronic loads.
[0004] However, in order to simulate the current change of 100A per microsecond, the electronic load in the prior art has a large overall volume and weight for the high-power switching power supply and high-power electronic load to be tested. For example, a 10KW electronic load needs to be equipped with a large heat sink and fan, so it is generally set to more than 30kg. For the convenience of testing, a 1m to 2m long cable needs to be set between the switching power supply and the electronic load for connection.
[0005] See also Figure 1 and Figure 2 , Figure 1 It is a structural block diagram of the electronic load test system in the prior art. Figure 2 yes Figure 1 The waveform diagram of the electronic load input signal and output signal is shown. The electronic load test system in the prior art includes a switching power supply 30, an electronic load 3, and a test cable 1 for connecting the electronic load 3 and the switching power supply 30. Since the simulated current changes rapidly during the test, the test cable 1 will form a certain parasitic inductance L, also called distributed inductance, which hinders the electronic load from changing the current quickly, thereby affecting the test results and making it impossible to determine whether the switching power supply 30 can meet the performance requirements of dynamic high-speed response. Figure 2 It can also be seen that the control signal I a The output current signal I1 is inconsistent with the output current signal I2. The output current signal I1 is obviously affected by the test cable and is slower than the input control signal I2. a .
[0006] Therefore, the electronic load test system in the prior art has serious deficiencies and cannot meet the needs of high dynamic performance testing of switching power supplies, and the detection error is relatively large. [Summary of the invention]
[0007] The present invention provides an electronic load testing system for solving the above-mentioned switching power supply dynamic response detection error.
[0008] The present invention provides an electronic load testing system, comprising a test cable, a first electronic load, a second electronic load and a control module, wherein the proximal end of the test cable is connected to a switching power supply; the first electronic load is arranged at the distal end of the test cable, and the test cable is arranged between the first electronic load and the switching power supply; the second electronic load is arranged at the proximal end of the test cable, close to the switching power supply or directly at the output end of the switching power supply; the control module is respectively connected to the first electronic load and the second electronic load, and inputs a first input signal and a second input signal that are arranged in association with each other, and the first electronic load and the second electronic load respectively output a first current and a second current to the switching power supply, so that the change of the total load current of the switching power supply is consistent with the change of the first input signal; wherein the change speed of the second current is faster than the change speed of the first current.
[0009] Compared with the prior art, the electronic load testing system provided by the present invention sets the first electronic load, the second electronic load and the control module, and controls the first electronic load to generate the main current required for the switching power supply test through the control module, and controls the second electronic load to generate the slave current required for the switching power supply test, so that the change of the total load current of the switching power supply can be consistent with the change of the first input signal provided by the control module, thereby eliminating the influence of the distributed inductance in the test cable on the detection and meeting the performance test requirements of the switching power supply for dynamic high-speed response.
[0010] In addition, the second electronic load only processes high-speed dynamic pulse currents that the first electronic load cannot process, that is, the second current changes faster than the first current. This setting method can make the power consumption of the second electronic load lower, and the volume and weight can be set smaller, so that the second electronic load is set at the near end of the test cable, close to the switching power supply or directly at the output end of the switching power supply, the test process is more convenient to install, and the test results will not be affected by the distributed inductance in the test cable.
Brief Description of the Drawings
[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:
[0012] Figure 1 It is a structural block diagram of an electronic load test system of the prior art;
[0013] Figure 2 yes Figure 1 The electronic load input signal I a and the waveform diagram of the output signal I1;
[0014] Figure 3 is a structural block diagram of the electronic load testing system provided by the present invention;
[0015] Figure 4 is a topological diagram of the first embodiment of the electronic load testing system provided by the present invention;
[0016] Figure 5 yes Figure 4 The second input signal I b Waveform diagram of
[0017] Figure 6 yes Figure 4 The waveform diagram of the second current I2 shown;
[0018] Figure 7 yes Figure 4 The waveform diagram of the total load current I shown;
[0019] Figure 8 is a topological diagram of the second embodiment of the electronic load testing system provided by the present invention;
[0020] Fig. 9 yes Figure 8 The circuit diagram of the first electronic load shown; and
[0021] Fig.10 yes Figure 8 The circuit diagram of the second electronic load is shown. [Specific implementation method]
[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0023] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0024] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0025] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0026] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.
[0027] Please also see Figure 3 and Figure 4 An electronic load test system 10 includes a test cable 1, a first electronic load 3, a second electronic load 5 and a control module 7. The proximal end of the test cable 1 is connected to a switching power supply 30, the first electronic load 3 is arranged at the distal end of the test cable 1, and the test cable 1 is arranged between the first electronic load 3 and the switching power supply 30. The second electronic load 5 is arranged at the proximal end of the test cable 1, close to the switching power supply 30 or directly at the output end of the switching power supply 30. The control module 7 is respectively connected to the first electronic load 3 and the second electronic load 5, and inputs a first input signal I which is set in association with each other. a and the second input signal I b, the first electronic load 3 and the second electronic load 5 respectively output the first current I1 and the second current I2 to the switching power supply 30, so that the change of the total load current I of the switching power supply 30 is consistent with the first input signal I a The change of the second current I2 is kept consistent. Wherein, the change speed of the second current I2 is faster than the change speed of the first current I1.
[0028] It should be noted that the proximal end and the distal end of the test cable 1 are relative to the switching power supply 30, the end close to the switching power supply 30 is the proximal end, and the end far away from the switching power supply 30 is the distal end. In order to test the high-power switching power supply 30, the power of the first electronic load 3 is also relatively large, and the volume and weight are relatively large, so a 1m to 2m test cable 1 must be set for connection. Therefore, the first electronic load 3 is arranged at the distal end of the test cable 1, and the second electronic load 5 is used to provide the second current I2 to process the high-speed dynamic pulse current that the first electronic load 3 cannot process due to the distributed inductance of the test cable 1, so the dynamic power consumed is low, and the volume and weight are small, that is, the second current I2 changes faster than the first current I1, so the second electronic load 5 can be directly arranged at the proximal end of the test cable 1.
[0029] The electronic load test system 10 controls the first electronic load 3 to generate the main current required for the test of the switching power supply 30, that is, the first current I1, and controls the second electronic load 5 to generate the slave current required for the test of the switching power supply 30, that is, the second current I2, through the control module 7, so that the change of the total load current I of the switching power supply 30 can be consistent with the first input signal I provided by the control module 7. a The changes are kept consistent, thereby eliminating the influence of the distributed inductance in the test cable 1 on the detection and meeting the performance test requirements of the switching power supply 30 for dynamic high-speed response.
[0030] At the same time, the electronic load test system 10 can set the second electronic load 5 at the near end of the test cable 1, close to the switching power supply 30 or directly at the output end of the switching power supply 30, so that the test process installation is more convenient. In addition, since the second electronic load 5 is set at the near end of the test cable 1, it will not be affected by the distributed inductance in the test cable 1, and can be precisely controlled, so that the test result of the switching power supply 30 will not be affected by the distributed inductance in the test cable 1.
[0031] In addition, the first input signal I a With the second input signal I bCorrelation means that there is a certain correlation between two signals. Specifically, through the adjustment of the control module 7, the first electronic load 3 and the second electronic load 5 receive the first input signal I a and the second input signal I b After that, the output first current I1 and the second current I2 are added to the first input signal I a That is, the change of the total load current I is consistent with the change of the first input signal I a For the first input signal I a With the second input signal I b The size, change speed and other parameters are not limited here, but only indicate that there is a certain correlation between the two signals. By inputting the second input signal I b , a high dynamic performance test of the switching power supply 30 can be achieved.
[0032] To further explain the principle of the electronic load test system 10, please continue to refer to Figure 2 , Figures 5 to 7 , respectively, are the first input signal I a , the first current I1, the second input signal I b , the second current I2 and the total load current I waveform diagram. The first input signal I a Provided for the control module 7, in order to test the high dynamic performance of the switching power supply 30, assuming that the first input signal I a The first electronic load 3 is input from time t1 and rises rapidly, with the rising speed set to 100A per microsecond, and reaches the maximum value after Δt microseconds and remains unchanged. Ideally, the first current I1 output by the first electronic load 3 should be consistent with the first input signal I a However, due to the influence of the distributed inductance in the test cable 1, the first current I1 rises significantly slower than the first input signal I a , resulting in the first current I1 reaching the maximum value at time t2, and the rising time is t2-t1>Δt.
[0033] In order to compensate for the difference between the two, the control module 7 provides the second input signal I to the second electronic load 5. b Since the second current I2 output by the second electronic load 5 is not affected by the distributed inductance of the test cable 1, the second current I2 is proportional to the second input signal I b When the control module 7 provides the first input signal I aand the second input signal I b After that, the total load current I of the switching power supply 30 is equal to the sum of the first current I1 and the second current I2. When the change of the total load current I is equal to the change of the first input signal I a When the changes of remain consistent, the purpose of detecting the high dynamic performance of the switching power supply 30 is achieved.
[0034] Please continue reading Figure 8 , Figure 8 1 is a topological diagram of the second embodiment of the electronic load test system provided by the present invention. For more accurate and convenient control, the control module 7 includes a signal generator 71, a signal detector 73 and a signal processor 75. The signal generator 71 is connected to the first electronic load 3 to provide the first input signal I a , the first electronic load 3 outputs the first current I1. The signal detector 73 is disposed at one end of the first electronic load 3 to detect the first current I1 output by the first electronic load 3. The signal processor 75 is connected to the signal generator 71, the signal detector 73 and the second electronic load 5 respectively, and converts the first input signal I a The difference between the total load current I and the first input signal I1 is input into the second electronic load 5, and the second electronic load 5 outputs the second current I2. a The changes remain consistent.
[0035] It should be noted that the control module 7 can not only provide signals to the first electronic load 3 and the second electronic load 5 respectively, but also provide signals to the first electronic load 3 or the second electronic load 5 separately. For example, in this embodiment, the control module 7 provides the first input signal I to the first electronic load 3 separately by setting the signal generator 71. a , and then through the signal detector 73 and the signal processor 75, thereby generating the second input signal I b , and the second input signal I b is equal to the first input signal I a The difference between the first current I1 and the first current I2 is used to realize the first input signal I a With the second input signal I b Interrelated settings.
[0036] The control module 7 provides the first input signal I a and the second input signal I b , the first input signal I may be incorrectly calculated due to a calculation error in a certain link or circuit in the electronic load test system 10. aand the second input signal I b The signal detector 73 can directly measure the first current I1, and the signal processor 75 can directly calculate the first input signal I a By calculating the difference between the first current I1 and the first current I2, the influence of the test cable 1 on the first electronic load 3 can be clearly understood, thereby providing the second electronic load 5 with a fully matched and complementary second input signal I b This configuration only requires one signal generator 71 to enable the control module 7 to simultaneously and synchronously provide the first input signal I a and the second input signal I b , which is convenient for control and saves costs; and, the second input signal I b As the first current I1 changes, a corresponding change will be formed, so that the detection result is more accurate and effective.
[0037] Furthermore, the signal detector 73 and the signal processor 75 are arranged so that the total load current I and the first input signal I a In order to test the high dynamic performance of the switching power supply 30, the electronic load testing system 10 needs to ensure that the total load current I is equal to the first input signal I a The changes remain consistent.
[0038] The so-called consistency means that when the first input signal I a When the total load current I changes, the total load current I can change at the same time, and the speed of change is the same as the first input signal I a The same or linear relationship. Here is an example: the first input signal I a It starts to rise from 0A at time t1, reaches 100A after 1 microsecond, and no longer changes; synchronously, the total load current I starts to rise from 0A at time t1, reaches the highest point of the rise after 1 microsecond, and no longer changes; the current value at the highest point of the total load current I should be K*100A, where K is the correlation coefficient.
[0039] The total load current I and the first input signal I a When using the electronic load test system 10, the tester can control the first input signal I a The change curve of the total load current I can provide a change curve of the total load current I that can clearly understand the relevant parameters, thereby realizing the test of the switching power supply 30. In this embodiment, it is preferred that the total load current I and the first input signal I aThe scheme of maintaining equality can not only more effectively and intuitively determine the variation curve of the total load current I, but also make the design of the control module 7 simpler and more convenient, thereby saving the production cost of the electronic load test system 10.
[0040] In order to stabilize the total load current I and the first input signal I a Keep them equal, the signal detector 73 is set as a current sensor 731, the signal processor 75 is set as a subtractor 751, the signal generator 71 is connected to the non-inverting input terminal of the subtractor 751, the current sensor 731 is connected to the inverting input terminal of the subtractor 751, and the output terminal of the subtractor 751 is electrically connected to the second electronic load 5. The control module 7 sets the current sensor 731 at one end of the first electronic load 3, so as to detect the first current I1 output by the first electronic load 3 in real time, and input the first current I1 to the inverting input terminal of the subtractor 751. This setting method can ensure that the second input signal I1 input by the second electronic load 5 is b Completely equal to the first input signal I a and the first current I1, and the total load current I, the second current I2 and the first current I1 will follow the first input signal I in real time and stably. a Moreover, the overall structure of this arrangement is relatively simple, and the volume and weight of the control module 7 can be effectively controlled.
[0041] Please continue reading Fig. 9 and Fig.10 , are circuit diagrams of the first electronic load 3 and the second electronic load 5, respectively. The first electronic load 3 includes a first operational amplifier A1, a first sampling resistor R1 and a first MOS tube Q1. The first input signal I a The first sampling resistor R1 is provided between the remote end of the test cable 1 and the inverting input end of the first operational amplifier A1. The gate of the first MOS tube Q1 is connected to the output end of the first operational amplifier A1. The drain of the first MOS tube Q1 is connected to the remote end of the test cable 1. The source of the first MOS tube Q1 is connected to the first sampling resistor R1 and the inverting input end of the first operational amplifier A1. The first electronic load 3 realizes signal conversion by setting the first operational amplifier A1, the first sampling resistor and the first MOS tube Q1. When the first input signal I aAfter input, the gate voltage of the first MOS transistor Q1 is controlled, thereby controlling the drain current flowing through the first MOS transistor Q1 to achieve stepless regulation of the first current I1, and rely on the power dissipation of the first MOS transistor Q1 to consume electrical energy. The first operational amplifier A1 works in a negative feedback state, and its in-phase terminal voltage is equal to the inverting terminal voltage, so it can be achieved by adjusting the first input signal I a , thereby adjusting the change of the first current I1.
[0042] Correspondingly, the second electronic load 5 includes a second operational amplifier A2, a second sampling resistor R2 and a second MOS transistor Q2. b The second sampling resistor R2 is provided between the proximal end of the test cable 1 and the inverting input end of the second operational amplifier A2, the gate of the second MOS tube Q2 is connected to the output end of the second operational amplifier A2, the drain of the second MOS tube Q2 is connected to the proximal end of the test cable 1, and the source of the second MOS tube Q2 is connected to the second sampling resistor R2 and the inverting input end of the second operational amplifier A2. The circuit structure of the second electronic load 5 is similar to that of the first electronic load 3, except that the power of the second MOS tube Q2 is relatively small, and a large heat sink and fan are not required. The overall size of the second electronic load 5 is relatively small, so as to ensure that the second sampling resistor R2 and the drain of the second MOS tube Q2 can be connected to the proximal end of the test cable 1, or can be directly provided on the switching power supply 30.
[0043] The first electronic load 3 and the second electronic load 5 are set in the above manner, and the overall circuit structure is simple and not prone to error, and can effectively achieve the following change of the first current I1 and the second current I2. In order to ensure that the first electronic load 3 and the second electronic load 5 can cooperate with the control module 7 to achieve the total load current I and the first input signal I a The first operational amplifier A1 and / or the second operational amplifier A2 are provided with a signal converter 77 at the non-inverting input end, and the first input signal I a and / or the second input signal I bThe signal is input to the non-inverting input terminal of the first operational amplifier A1 and / or the second operational amplifier A2 through the signal converter 77. In this embodiment, the first electronic load 3 and the second electronic load 5 are both provided with the signal converter 77. By providing the signal converter 77, the output of the first electronic load 3 and the second electronic load 5 can be more accurately controlled, that is, the changes of the first current I1 and the second current I2 are both within the accurately controllable range, thereby achieving accurate control of the total load current I.
[0044] In addition, by setting the signal converter 77, the selection range of the test signal can be broadened. No matter it is a digital signal or an analog signal, the first input signal I provided by the signal generator 77 can be a It is not limited by the specific signal type, making the test more convenient. a With the second input signal I b Both are current setting signals. The signal generator 77 can convert the current setting signals into voltage signals, and input the voltage signals into the non-inverting input terminal of the transport amplifier, thereby realizing the driving control of the first electronic load 3 and the second electronic load 5.
[0045] In this embodiment, the load power of the first electronic load 3 is 80 to 120 times the load power of the second electronic load 5. For example, if the load power of the first electronic load 3 is set to 1KW, the power of the second electronic load 5 is set to 8W or 12W. The difference of 80 to 120 times in the power setting between the second electronic load 5 and the first electronic load 3 can effectively limit the size and weight of the second electronic load 5, making it easier to install; at the same time, it can effectively supplement the fast-changing pulse current that the first electronic load 3 cannot achieve.
[0046] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope of the present invention.
Claims
1. An electronic load test system, which provides a high dynamic performance load current for a high-power switching power supply under test, characterized in that: include: A test cable, the proximal end of which is connected to the switching power supply; a first electronic load, the first electronic load being disposed at a remote end of the test cable, the test cable being disposed between the first electronic load and the switch power supply; A second electronic load, which is disposed at the proximal end of the test cable, close to the switching power supply or directly at the output end of the switching power supply; and A control module, wherein the control module is connected to the first electronic load and the second electronic load respectively, and inputs a first input signal and a second input signal which are set in association with each other, and the first electronic load and the second electronic load respectively output a first current and a second current to the switching power supply, so that a change in the total load current is consistent with a change in the first input signal; The second current changing speed is faster than the first current changing speed.
2. The electronic load testing system according to claim 1, characterized in that: The control module comprises: a signal generator, the signal generator being connected to the first electronic load and providing the first input signal, so that the first electronic load outputs the first current; and a signal detector, the signal detector being disposed at one end of the first electronic load and detecting the first current output by the first electronic load; and A signal processor is connected to the signal generator, the signal detector and the second electronic load respectively, inputs the difference between the first input signal and the first current into the second electronic load, and the second electronic load outputs the second current.
3. The electronic load testing system according to claim 2, characterized in that: The total load current remains equal to the first input signal.
4. The electronic load testing system according to claim 3, characterized in that: The signal detector is set as a current sensor, the signal processor is set as a subtractor, the signal generator is connected to the non-inverting input end of the subtractor, the current sensor is connected to the inverting input end of the subtractor, and the output end of the subtractor is electrically connected to the second electronic load.
5. The electronic load testing system according to claim 1, characterized in that: The first electronic load comprises: a first operational amplifier, wherein the first input signal is input to a non-inverting input terminal of the first operational amplifier; a first sampling resistor, wherein the first sampling resistor is disposed between the far end of the test cable and the inverting input terminal of the first operational amplifier; and A first MOS transistor, wherein the gate of the first MOS transistor is connected to the output end of the first operational amplifier, the drain of the first MOS transistor is connected to the remote end of the test cable, and the source of the first MOS transistor is connected to the first sampling resistor and the inverting input end of the first operational amplifier.
6. The electronic load testing system according to claim 1, characterized in that: The second electronic load comprises: a second operational amplifier, wherein the second input signal is input to a non-inverting input terminal of the first operational amplifier; a second sampling resistor, wherein the second sampling resistor is disposed between the proximal end of the test cable and the inverting input terminal of the first operational amplifier; and A second MOS tube, wherein the gate of the second MOS tube is connected to the output end of the second operational amplifier, the drain of the second MOS tube is connected to the proximal end of the test cable, and the source of the second MOS tube is connected to the second sampling resistor and the inverting input end of the second operational amplifier.
7. The electronic load testing system according to claim 5 or 6, characterized in that: A signal converter is provided at the non-inverting input terminal of the first operational amplifier and / or the second operational amplifier, and the first input signal and / or the second input signal are input to the non-inverting input terminal of the first operational amplifier and / or the second operational amplifier through the signal converter.
8. The electronic load testing system according to claim 1, characterized in that: The load power of the first electronic load is 80 to 120 times the load power of the second electronic load.