Switching power supply output capacitor on-line detection method, system and medium

Abstract

The application provides a non-invasive LC filter structure switching power supply output capacitor online detection method, system and medium, the method comprises the following steps: when the switching power supply is normally running, the switching power supply output voltage signal, the output voltage ripple signal and the load current signal are synchronously collected; the working mode of the switching power supply is judged according to the output voltage ripple signal, if the switching power supply works in the DCM mode, the switching power supply output capacitor parameter is detected by using the DCM mode detection method, if the switching power supply works in the CCM mode, the switching power supply output capacitor parameter is detected by using the CCM mode detection method; the running state of the LC filter structure switching power supply is judged according to the capacitance value of the detected switching power supply output capacitor, the standard capacitance value of the capacitor, the resistance value of the equivalent series resistance and the standard resistance value of the equivalent series resistance. The application realizes that the output capacitor parameter of the switching power supply can be detected only by using the signals of the output end of the switching power supply.

Description

Technical Field

[0001] This invention relates to the field of switching power supply fault detection technology, and in particular to a non-invasive LC-type filter structure switching power supply output capacitor online detection method, system and medium. Background Technology

[0002] Switching power supplies have complex structures. AC-DC switching power supplies, which convert alternating current into constant direct current, often contain multiple modules, each with a different topology. DC-DC switching power supplies are essentially a part of AC-DC switching power supplies. There are many types of DC-DC converters in switching power supplies. Their basic circuit topologies are Buck converters, Boost converters, Buck-Boost converters, Cuk converters, Sepic converters, and Zeta converters. Other types of converters used later are derived from these six basic structures, and the final main topology output is basically the same as these six converters. These converters can be divided into two categories according to the filtering structure at the main topology output: one is the LC-type filtering structure consistent with the Buck converter, such as Cuk, Zeta, Forward, push-pull converters, and related derived topologies; the other is the pure capacitor-type filtering structure consistent with the Boost converter, such as Buck-Boost, Sepic, Flyback converters, and related derived topologies. The output capacitor is a weak link in a switching power supply and has a significant impact on the overall performance of the power supply. The parameters of the output capacitor in a switching power supply are directly related to the fault condition and service life of the power supply.

[0003] Testing methods that involve disassembling the switching power supply or removing capacitors may damage the power supply and reduce its lifespan. Summary of the Invention

[0004] The main objective of this invention is to provide a non-invasive online detection method, system, and medium for the output capacitor of a switching power supply with an LC-type filter structure. The aim is to enable the detection of the output capacitor parameters using only the signal from the output terminal of the switching power supply, without disassembling the power supply, thus avoiding any impact on the switching power supply and its application system.

[0005] To achieve the above objectives, this invention proposes a non-invasive online detection method for the output capacitor of a switching power supply with an LC-type filter structure. The method includes the following steps:

[0006] Step S10: During normal operation of the switching power supply, synchronously acquire the output voltage signal U of the switching power supply. O Output voltage ripple signal v o (t) and load current signal I O ;

[0007] Step S20: Determine the operating mode of the switching power supply based on the output voltage ripple signal. The operating mode includes DCM mode and CCM mode. If the switching power supply is operating in DCM mode, proceed to step S30. If the switching power supply is operating in CCM mode, proceed to step S40.

[0008] Step S30: Detect the output capacitor parameters of the switching power supply using the DCM mode detection method;

[0009] Step S40: Detect the output capacitor parameters of the switching power supply using the CCM mode detection method;

[0010] Step S50: Determine the operating status of the LC-type filter structure switching power supply based on the detected capacitance value of the output capacitor, the standard capacitance value of the capacitor, the resistance value of the equivalent series resistance, and the standard resistance value of the equivalent series resistance.

[0011] A further technical solution of the present invention is that step S30, the step of detecting the output capacitor parameters of the switching power supply using the DCM mode detection method, includes:

[0012] Step S31: Calculate the slope k of the linear change in output voltage ripple during the stage when the inductor current is 0. C And then according to Determine the capacitance value of the output capacitor;

[0013] Step S32: Calculate the duty cycle D of the switching transistor during its on-state and the duty cycle D′ of the inductor current not being zero during the off-state phase using the output voltage ripple. Calculate the maximum inductor current;

[0014] Step S33: Utilize Calculate the integral of the capacitor current during the turn-on phase of the switching transistor;

[0015] Step S34: Utilize Calculate the ESR value of the output capacitor.

[0016] A further technical solution of the present invention is that step S40 includes:

[0017] Step 41: Connect an RC circuit with known parameters in parallel to the output of the switching power supply, and then collect the output voltage ripple signal v of the switching power supply. om (t);

[0018] Step 42: Based on the output voltage ripple signal v of the switching power supply before the parallel RC circuit... o (t), calculate the duty cycle D1 and switching period T of the switching power supply. s and the peak-to-peak output voltage ripple Δv o1 reuse Calculate the size of const1;

[0019] Step 43: Based on the output voltage ripple signal v of the switching power supply after the parallel RC circuit. om (t), calculate the new duty cycle D2 of the switching power supply, and the switching period T. s and the peak-to-peak output voltage ripple Δv o2 reuse Calculate the size of const2;

[0020] Step44: Utilize Calculate the ESR value of the output capacitor of the switching power supply, where ESRb is the resistance value of the parallel resistor;

[0021] Step45: Utilize Find the maximum current of the output capacitor;

[0022] Step 46: Utilize Calculate the value of k2, and at the same time use Calculate the inductance value and use Calculate the time constant;

[0023] Step 47: According to Reverse the signal of capacitor current during the turn-off phase of the switching transistor;

[0024] Step 48: Arbitrarily select two moments during the turn-off phase of the switching transistor, such as t 1m and t 3m ,use Calculate the capacitance value of the output capacitor.

[0025] To achieve the above objectives, the present invention also proposes a non-invasive LC-type filter structure switching power supply output capacitor online detection system. The system includes a memory, a processor, and a non-invasive LC-type filter structure switching power supply output capacitor online detection program stored on the processor. When the processor runs the non-invasive LC-type filter structure switching power supply output capacitor online detection program, it executes the following steps:

[0026] Step S10: During normal operation of the switching power supply, synchronously acquire the output voltage signal U of the switching power supply. O Output voltage ripple signal v o (t) and load current signal I O ;

[0027] Step S20: Determine the operating mode of the switching power supply based on the output voltage ripple signal. The operating mode includes DCM mode and CCM mode. If the switching power supply is operating in DCM mode, proceed to step S30. If the switching power supply is operating in CCM mode, proceed to step S40.

[0028] Step S30: Detect the output capacitor parameters of the switching power supply using the DCM mode detection method;

[0029] Step S40: Detect the output capacitor parameters of the switching power supply using the CCM mode detection method;

[0030] Step S50: Determine the operating status of the LC-type filter structure switching power supply based on the detected capacitance value of the output capacitor, the standard capacitance value of the capacitor, the resistance value of the equivalent series resistance, and the standard resistance value of the equivalent series resistance.

[0031] A further technical solution of the present invention is that, when the processor runs the online detection program for the output capacitor of the non-intrusive LC-type filter structure switching power supply, it also performs the following steps:

[0032] Step S31: Calculate the slope k of the linear change in output voltage ripple during the stage when the inductor current is 0. C And then according to Determine the capacitance value of the output capacitor;

[0033] Step S32: Calculate the duty cycle D of the switching transistor during its on-state and the duty cycle D′ of the inductor current not being zero during the off-state phase using the output voltage ripple. Calculate the maximum inductor current;

[0034] Step S33: Utilize Calculate the integral of the capacitor current during the turn-on phase of the switching transistor;

[0035] Step S34: Utilize Calculate the ESR value of the output capacitor.

[0036] A further technical solution of the present invention is that, when the processor runs the online detection program for the output capacitor of the non-intrusive LC-type filter structure switching power supply, it also performs the following steps:

[0037] Step 41: Connect an RC circuit with known parameters in parallel to the output of the switching power supply, and then collect the output voltage ripple signal v of the switching power supply. om (t);

[0038] Step 42: Based on the output voltage ripple signal v of the switching power supply before the parallel RC circuit... o (t), calculate the duty cycle D1 and switching period T of the switching power supply. s and the peak-to-peak output voltage ripple Δv o1 reuse Calculate the size of const1;

[0039] Step 43: Based on the output voltage ripple signal v of the switching power supply after the parallel RC circuit. om (t), calculate the new duty cycle D2 of the switching power supply, and the switching period T. s and the peak-to-peak output voltage ripple Δv o2 reuse Calculate the size of const2;

[0040] Step44: Utilize Calculate the ESR value of the output capacitor of the switching power supply, where ESRb is the resistance value of the parallel resistor;

[0041] Step45: Utilize Find the maximum current of the output capacitor;

[0042] Step 46: Utilize Calculate the value of k2, and at the same time use Calculate the inductance value and use Calculate the time constant;

[0043] Step 47: According to Reverse the signal of capacitor current during the turn-off phase of the switching transistor;

[0044] Step 48: Arbitrarily select two moments during the turn-off phase of the switching transistor, such as t 1m and t 3m ,use Calculate the capacitance value of the output capacitor.

[0045] To achieve the above objectives, the present invention also proposes a computer-readable storage medium storing a non-intrusive LC-type filter structure switching power supply output capacitor online detection program, wherein the non-intrusive LC-type filter structure switching power supply output capacitor online detection program is executed by a processor to perform the steps of the method described above.

[0046] The beneficial effects of the non-invasive LC-type filter structure online detection method, system, and dielectric of the switching power supply output capacitor of this invention are:

[0047] (1) The detection method proposed in this invention is applicable to the online detection of output capacitor parameters of various AC-DC and DC-DC switching power supplies with LC-type filter structure at the main topology output terminal of DC-DC converter module;

[0048] (2) The detection method proposed in this invention is a non-invasive online detection method. It can detect the output capacitor parameters using only the signal at the output end of the switching power supply. It does not require disassembling the power supply and has no impact on the switching power supply.

[0049] (3) The detection method proposed in this invention only needs to use the output voltage, output voltage ripple and load current when the switching power supply is working normally to calculate the output capacitor parameters in DCM mode. Then, by connecting an RC circuit with known parameters in parallel to the output terminal of the switching power supply, the output capacitor parameters in CCM mode can be calculated.

[0050] (4) The detection method proposed in this invention is not related to the input signal and circuit structure of the front end of the switching power supply, but only to the filter structure of the output end of the main topology. This method is applicable to LC-type filter structures consistent with Buck converters, such as Cuk, Zeta, Forward, push-pull converters and related derivative topologies. It is applicable to a wide variety of switching power supplies and has a wide range of applications. Attached Figure Description

[0051] Figure 1 This is a flowchart illustrating a preferred embodiment of the online detection method for the output capacitor of a non-invasive LC-type filter structure switching power supply according to the present invention.

[0052] Figure 2 This is a schematic diagram of the basic structure of a Buck converter;

[0053] Figure 3 This is the topology diagram of the Buck converter's switching transistors in the on-state.

[0054] Figure 4 This is the topology of the Buck converter when the switching transistor is off and the inductor current does not drop to zero when Q is turned off.

[0055] Figure 5 This is the topology of the Buck converter when the switching transistor is off and the inductor current drops to 0 when Q is turned off.

[0056] Figure 6 This is a schematic diagram of the waveforms of various electrical quantities in an LC-type filter structure when the inductor current is discontinuous;

[0057] Figure 7 This is a schematic diagram of the waveforms of various electrical quantities in an LC-type filter structure when the inductor current is continuous.

[0058] Figure 8 This is a schematic diagram of the calculation model for the output capacitor value of an LC-type filter structure switching power supply.

[0059] Figure 9 It is the point in time chosen within a switching cycle to determine the capacitance value.

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0061] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0062] This invention proposes a non-invasive online detection method for the output capacitor of a switching power supply with an LC-type filter structure. Applied to the field of switching power supply fault detection technology, this method is suitable for online detection of the output capacitor parameters of various AC-DC and DC-DC switching power supply topologies where the main topology output filter structure of the DC-DC converter module is an LC-type filter structure. This invention requires connecting an RC circuit with a known resistance value in parallel at the output of the switching power supply. By acquiring the output voltage ripple signal before and after connecting the RC circuit, the parameters of the switching power supply output capacitor can be calculated without disassembling the capacitor, thus having no impact on the switching power supply. This non-invasive online detection method for the output capacitor of a switching power supply with an LC-type filter structure is independent of the input signal and circuit structure at the front end of the switching power supply, and is applicable to a wide range of switching power supplies.

[0063] Specifically, please refer to Figure 1 A preferred embodiment of the non-invasive LC-type filter structure switching power supply output capacitor online detection method of the present invention includes the following steps:

[0064] Step S10: During normal operation of the switching power supply, synchronously acquire the output voltage signal U of the switching power supply. O Output voltage ripple signal v o (t) and load current signal I O ;

[0065] Step S20: Determine the operating mode of the switching power supply based on the output voltage ripple signal. The operating mode includes DCM mode and CCM mode. If the switching power supply is operating in DCM mode, proceed to step S30. If the switching power supply is operating in CCM mode, proceed to step S40.

[0066] Step S30: Detect the output capacitor parameters of the switching power supply using the DCM mode detection method;

[0067] Step S40: Detect the output capacitor parameters of the switching power supply using the CCM mode detection method;

[0068] Step S50: Determine the operating status of the LC-type filter structure switching power supply based on the detected capacitance value of the output capacitor, the standard capacitance value of the capacitor, the resistance value of the equivalent series resistance, and the standard resistance value of the equivalent series resistance.

[0069] Specifically, step S30, which involves detecting the output capacitor parameters of the switching power supply using the DCM mode detection method, includes:

[0070] Step S31: Calculate the slope k of the linear change in output voltage ripple during the stage when the inductor current is 0. C And then according to Determine the capacitance value of the output capacitor;

[0071] Step S32: Calculate the duty cycle D of the switching transistor during its on-state and the duty cycle D′ of the inductor current not being zero during the off-state phase using the output voltage ripple. Calculate the maximum inductor current:

[0072] Step S33: Utilize Calculate the integral of the capacitor current during the turn-on phase of the switching transistor;

[0073] Step S34: Utilize Calculate the ESR value of the output capacitor.

[0074] Step S40 includes:

[0075] Step 41: Connect an RC circuit with known parameters in parallel to the output of the switching power supply, and then collect the output voltage ripple signal v of the switching power supply. om (t);

[0076] Step 42: Based on the output voltage ripple signal v of the switching power supply before the parallel RC circuit... o (t), calculate the duty cycle D1 and switching period T of the switching power supply. s and the peak-to-peak output voltage ripple Δv o1 reuse Calculate the size of const1;

[0077] Step 43: Based on the output voltage ripple signal v of the switching power supply after the parallel RC circuit. om (t), calculate the new duty cycle D2 of the switching power supply, and the switching period T. s and the peak-to-peak output voltage ripple Δv o2 reuse Calculate the size of const2;

[0078] Step44: Utilize Calculate the ESR value of the output capacitor of the switching power supply, where ESRb is the resistance value of the parallel resistor;

[0079] Step45: Utilize Find the maximum current of the output capacitor;

[0080] Step 46: Utilize Calculate the value of k2, and at the same time use Calculate the inductance value and use Calculate the time constant;

[0081] Step 47: According to Reverse the signal of capacitor current during the turn-off phase of the switching transistor;

[0082] Step 48: Arbitrarily select two moments during the turn-off phase of the switching transistor, such as t 1m and t 3m ,use Calculate the capacitance value of the output capacitor.

[0083] The following combination Figures 2 to 9 The present invention provides a more detailed description of the online detection method for the output capacitor of a non-invasive LC-type filter structure switching power supply.

[0084] Online testing method for output capacitor of LC-type filter structure switching power supply:

[0085] The online testing method proposed in this invention is for AC-DC and DC-DC switching power supplies with an LC-type filter structure at the output of the main topology, which is consistent with that of the Buck converter. Therefore, the Buck converter is used as an example to illustrate this testing method; the testing method for other switching power supplies with an LC-type filter structure at the output of the main topology is completely consistent with that for the Buck converter.

[0086] Buck converters typically operate in CCM and DCM modes. The inductor current differs between these two modes, and the detection methods also differ. The output capacitance detection methods for each mode will be explained separately. A basic structural diagram of a Buck converter is shown below. Figure 2 As shown, the current of the power supply is i. s The current flowing through the inductor is i L The current flowing through the capacitor is i C The load current is i O The input voltage is V. in The output voltage is V O The voltage across the capacitor is the output voltage V of the converter. O .

[0087] When the switching transistor is turned on, the Buck converter topology is as follows: Figure 3 As shown, when the switching transistor is off and the inductor current does not drop to zero, the Buck converter topology is as follows: Figure 4 As shown, when the inductor current drops to 0, the Buck converter topology is as follows: Figure 5 As shown. The relationship between the various electrical quantities is shown in equation (1):

[0088] i L =i C +i O (1)

[0089] Method for detecting the output capacitor of a switching power supply in DCM mode:

[0090] The output capacitor of a Buck converter consists of a pure capacitor and an equivalent series resistance connected in series. When the Buck converter operates in DCM mode, the inductor current exhibits three operating modes. The waveform diagrams of the electrical parameters of each component are shown below. Figure 6 As shown. During the switch-off phase, when the inductor current drops to 0, the output voltage ripple decreases linearly. The operating mode of the Buck converter can be seen from the waveform of the output voltage ripple. The parameters of the output capacitor can be solved using the output voltage ripple and the load current. For the Buck converter in DCM mode, the duty cycle when the switch is on is D, and the duty cycle when the inductor current is not zero when the switch is off is D′.

[0091] from Figure 7 As can be seen from the data, t0~t2 is the rising stage of the inductor current when the switch is on; t2~t4 is the falling stage of the inductor current when the switch is off; and t4~t5 is the stage where the inductor current is 0 when the switch is off. From v... o (t4) to v o (t5), the relationship between the power supply output voltage ripple and the capacitor current is shown in equation (2).

[0092]

[0093] During the t4 to t5 stage, due to i C (t)=-I O This eliminates the effect of ESR, simplifying equation (2) to equation (3). The slope k of the output voltage ripple change during the t4-t5 stage is then calculated. C Then, based on the load current of the switching power supply, the capacitance value of the output capacitor can be calculated using equation (4).

[0094]

[0095]

[0096]

[0097] When the Buck converter operates in DCM mode, since the average inductor current equals the load current, the maximum inductor current can be derived as shown in equation (5). The capacitor current is the inductor current minus the load current; therefore, from t0 to t2, the integral of the capacitor current is calculated as shown in equation (6). From t0 to t2, the relationship between the switching power supply output voltage and the capacitor current is shown in equation (7). Based on the calculated capacitor value and the integral of the capacitor current, the ESR value of the output capacitor can be calculated as shown in equation (8). LpBy substituting S, C, and the output voltage ripple of the switching power supply into equation (8), the ESR value of the output capacitor can be calculated.

[0098]

[0099]

[0100]

[0101]

[0102] Method for detecting the output capacitor of a switching power supply in CCM mode:

[0103] (1) ESR calculation method:

[0104] When the Buck converter operates in CCM mode, the inductor current exhibits two operating modes, and the waveform diagrams of the electrical parameters of each component are shown below. Figure 7 As shown. Switching power supplies always have ripple. When the switch is on, the output voltage rises; when the switch is off, the output voltage falls. The operating mode of the Buck converter can be seen from the waveform of the output voltage ripple, and the ESR value of the output capacitor can be calculated using the output voltage ripple.

[0105] Ignoring output current ripple, the capacitor current ripple and inductor current ripple are consistent. For a Buck converter in CCM mode, the duty cycle is D1. When t0 = 0, the voltage across the equivalent series resistance reaches its trough, while the voltage across the pure capacitor is the output voltage V. O ;exist At t2 = D1T, the voltage across the equivalent series resistance is 0, while the voltage across the pure capacitor reaches its trough; s At that time, the voltage across the equivalent series resistance reaches its peak value, while the voltage across the pure capacitor is the output voltage V. O Based on the above relationships, the output voltage ripple can be obtained as shown in equation (8).

[0106] v o (t2)-v o (t0)=v ESR (t2)-v ESR (t0)=Δv o =ESRΔi C (8)

[0107] During the switching transistor's off-phase, the capacitor current is assumed to decrease linearly, and the slope of this current decrease is denoted as k2. The relationship between the capacitor current change slope, ESR, and output voltage ripple is shown in equation (9). After connecting an RC series circuit with a known capacitance value Cb and resistance value ESRb in parallel at the output of the switching power supply, the slope of the total capacitor current at the new output of the switching power supply, the relationship between ESR2 and output voltage ripple is shown in equation (10). Here, ESR2 is the parallel value of ESR and ESRb, and its value is expressed in equation (11). The ESR value of the output capacitor of the switching power supply can be obtained from equations (9), (10), and (11) as shown in equation (12).

[0108]

[0109]

[0110]

[0111]

[0112] (2) Capacity calculation method:

[0113] For an LC-type filter structure switching power supply operating in CCM mode, the duty cycle is D1. Ignoring output current ripple, the capacitor current ripple and inductor current ripple are consistent. Since the ESR value of the output capacitor has already been calculated, the peak capacitor current is calculated as shown in equation (13). During the power supply's drooping phase, the inductor value is calculated based on the relationship between the slope of the linear drooping capacitor current and the inductance value, as shown in equation (14). During the switching transistor's turn-off phase, the calculation model for the output capacitor value of the LC-type filter structure switching power supply is as follows: Figure 8 As shown, according to Figure 8 The model is derived from Kirchhoff's voltage law, and the voltage equation is given by equation (15). Equation (15) is a first-order linear non-homogeneous differential equation. Ignoring the magnitude of the ESR voltage, the capacitor voltage is equivalent to the output voltage, i.e., U. C =U O Solving equation (15) yields the solution for the capacitor current, as shown in equation (16), where the time constant is: Based on equations (13), (14), and (16), the current signal of the output capacitor during the switching transistor's turn-off phase can be deduced. Using this deduced capacitor current signal, the capacitance value can be directly calculated. During the power supply's turn-off phase, two arbitrary time points can be selected, such as... Figure 9 t in 1m and t 3mTwo points can be used to calculate the capacitance value. The relationship between the capacitor voltage and the capacitor current is shown in equation (17). Using the calculated ESR value and the inverted capacitor current signal, the capacitance value is calculated as shown in equation (18).

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120] Application examples:

[0121] A switching power supply with an LC-type filter structure at the output of any DC-DC converter was simulated in Saber. Taking a forward converter as an example, the output voltage ripple and average output voltage before and after the parallel RC circuit in CCM mode were obtained. The capacitance and ESR of the output capacitor were calculated using the method proposed in this invention. Simulations were performed with different capacitor parameters, and the parameters of the output capacitor calculated using the method proposed in this invention are shown in Table 1. As can be seen from Table 1, the calculated capacitance and ESR values ​​under different capacitor parameter conditions have very small errors. The capacitance calculation error is almost 3%, and the ESR calculation error is also basically within 1%, indicating that the method is feasible.

[0122] Table 1 Simulation Calculation Results of Output Capacitor Parameters for LC-Type Filtered Switching Power Supply

[0123]

[0124] The beneficial effects of the non-invasive LC-type filter structure online detection method for the output capacitor of a switching power supply according to the present invention are:

[0125] (1) The detection method proposed in this invention is applicable to the online detection of the output capacitor parameters of various AC-DC and DC-DC switching power supplies with LC-type filter structure at the main topology output terminal of DC-DC converter modules;

[0126] (2) The detection method proposed in this invention is a non-invasive online detection method. It can detect the output capacitor parameters using only the signal at the output end of the switching power supply. It does not require disassembling the power supply and has no impact on the switching power supply.

[0127] (3) The detection method proposed in this invention only needs to use the output voltage, output voltage ripple and load current when the switching power supply is working normally to calculate the output capacitor parameters in DCM mode. Then, by connecting an RC circuit with known parameters in parallel to the output terminal of the switching power supply, the output capacitor parameters in CCM mode can be calculated.

[0128] (4) The detection method proposed in this invention is not related to the input signal and circuit structure of the front end of the switching power supply, but only to the filter structure of the output end of the main topology. This method is applicable to LC-type filter structures consistent with Buck converters, such as Cuk, Zeta, Fotward, push-pull converters and related derivative topologies. It is applicable to a wide variety of switching power supplies and has a wide range of applications.

[0129] To achieve the above objectives, the present invention also proposes a non-invasive LC-type filter structure switching power supply output capacitor online detection system. The system includes a memory, a processor, and a non-invasive LC-type filter structure switching power supply output capacitor online detection program stored on the processor. When the processor runs the non-invasive LC-type filter structure switching power supply output capacitor online detection program, it executes the following steps:

[0130] Step S10: During normal operation of the switching power supply, synchronously acquire the output voltage signal U of the switching power supply. O Output voltage ripple signal v o (t) and load current signal I O ;

[0131] Step S20: Determine the operating mode of the switching power supply based on the output voltage ripple signal. The operating mode includes DCM mode and CCM mode. If the switching power supply is operating in DCM mode, proceed to step S30. If the switching power supply is operating in CCM mode, proceed to step S40.

[0132] Step S30: Detect the output capacitor parameters of the switching power supply using the DCM mode detection method;

[0133] Step S40: Detect the output capacitor parameters of the switching power supply using the CCM mode detection method;

[0134] Step S50: Determine the operating status of the LC-type filter structure switching power supply based on the detected capacitance value of the output capacitor, the standard capacitance value of the capacitor, the resistance value of the equivalent series resistance, and the standard resistance value of the equivalent series resistance.

[0135] Furthermore, when the processor runs the online detection program for the output capacitor of the non-intrusive LC-type filter structure switching power supply, it also performs the following steps:

[0136] Step S31: Calculate the slope k of the linear change in output voltage ripple during the stage when the inductor current is 0. C And then according to Determine the capacitance value of the output capacitor;

[0137] Step S32: Calculate the duty cycle D of the switching transistor during its on-state and the duty cycle D′ of the inductor current not being zero during the off-state phase using the output voltage ripple. Calculate the maximum inductor current;

[0138] Step S33: Utilize Calculate the integral of the capacitor current during the turn-on phase of the switching transistor;

[0139] Step S34: Utilize Calculate the ESR value of the output capacitor.

[0140] Furthermore, when the processor runs the online detection program for the output capacitor of the non-intrusive LC-type filter structure switching power supply, it also performs the following steps:

[0141] Step 41: Connect an RC circuit with known parameters in parallel to the output of the switching power supply, and then collect the output voltage ripple signal v of the switching power supply. om (t);

[0142] Step 42: Based on the output voltage ripple signal v of the switching power supply before the parallel RC circuit... o (t), calculate the duty cycle D1 and switching period T of the switching power supply. s and the peak-to-peak output voltage ripple Δv o1 reuse Calculate the size of const1;

[0143] Step 43: Based on the output voltage ripple signal v of the switching power supply after the parallel RC circuit. om (t), calculate the new duty cycle D2 of the switching power supply, and the switching period T. s and the peak-to-peak output voltage ripple Δv o2 reuse Calculate the size of const2;

[0144] Step44: Utilize Calculate the ESR value of the output capacitor of the switching power supply, where ESRb is the resistance value of the parallel resistor;

[0145] Step45: Utilize Find the maximum current of the output capacitor;

[0146] Step 46: Utilize Calculate the value of k2, and at the same time use Calculate the inductance value and use Calculate the time constant;

[0147] Step 47: According to Reverse the signal of capacitor current during the turn-off phase of the switching transistor;

[0148] Step 48: Arbitrarily select two moments during the turn-off phase of the switching transistor, such as t 1m and t 3m ,use Calculate the capacitance value of the output capacitor.

[0149] The advantages of the non-invasive LC-type filter structure online detection system for switching power supply output capacitors of this invention are:

[0150] (1) The detection method proposed in this invention is applicable to the online detection of the output capacitor parameters of various AC-DC and DC-DC switching power supplies with LC-type filter structure at the main topology output terminal of DC-DC converter modules;

[0151] (2) The detection method proposed in this invention is a non-invasive online detection method. It can detect the output capacitor parameters using only the signal at the output end of the switching power supply. It does not require disassembling the power supply and has no impact on the switching power supply.

[0152] (3) The detection method proposed in this invention only needs to use the output voltage, output voltage ripple and load current when the switching power supply is working normally to calculate the output capacitor parameters in DCM mode. Then, by connecting an RC circuit with known parameters in parallel to the output terminal of the switching power supply, the output capacitor parameters in CCM mode can be calculated.

[0153] (4) The detection method proposed in this invention is not related to the input signal and circuit structure of the front end of the switching power supply, but only to the filter structure of the output end of the main topology. This method is applicable to LC-type filter structures consistent with Buck converters, such as Cuk, Zeta, Forward, push-pull converters and related derivative topologies. It is applicable to a wide variety of switching power supplies and has a wide range of applications.

[0154] To achieve the above objectives, the present invention also proposes a computer-readable storage medium storing a non-intrusive LC-type filter structure switching power supply output capacitor online detection program. When the non-intrusive LC-type filter structure switching power supply output capacitor online detection program is run by a processor, the steps described in the above embodiments are executed, and will not be repeated here.

[0155] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural changes made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A non-invasive online detection method for the output capacitor of a switching power supply with an LC-type filter structure, characterized in that, The method includes the following steps: Step S10: When the switching power supply is operating normally, synchronously acquire the output voltage signal of the switching power supply. Output voltage ripple signal and load current signal ; Step S20: Determine the operating mode of the switching power supply based on the output voltage ripple signal. The operating mode includes DCM mode and CCM mode. If the switching power supply is operating in DCM mode, proceed to step S30. If the switching power supply is operating in CCM mode, proceed to step S40. Step S30: Detect the output capacitor parameters of the switching power supply using the DCM mode detection method; Step S40: Detect the output capacitor parameters of the switching power supply using the CCM mode detection method; Step S50: Determine the operating status of the LC-type filter structure switching power supply based on the detected capacitance value of the switching power supply output capacitor, the standard capacitance value of the capacitor, the resistance value of the equivalent series resistance, and the standard resistance value of the equivalent series resistance. Step S30, the step of detecting the output capacitor parameters of the switching power supply using the DCM mode detection method, includes: Step S31: Calculate the slope of the linear change in output voltage ripple during the stage when the inductor current is 0. And then according to Determine the capacitance value of the output capacitor; Step S32: Calculate the duty cycle of the switching transistor in the switching power supply using the output voltage ripple. Duty cycle during which the inductor current is not zero during the switching transistor's off-state phase ,use Calculate the maximum inductor current; Step S33: Utilize Calculate the integral of the capacitor current during the turn-on phase of the switching transistor; Step S34: Utilize Calculate the ESR value of the output capacitor; Step S40 includes: Step 41: Connect an RC circuit with known parameters in parallel to the output of the switching power supply, and then collect the output voltage ripple signal of the switching power supply. ; Step 42: Based on the output voltage ripple signal of the switching power supply before the parallel RC circuit. Calculate the duty cycle of the switching power supply. Switching cycle and peak-to-peak output voltage ripple reuse Calculate Size; Step 43: Based on the output voltage ripple signal of the switching power supply after the parallel RC circuit. Find the new duty cycle of the switching power supply. Switching cycle and peak-to-peak output voltage ripple reuse Calculate Size; Step44: Utilize Calculate the ESR value of the output capacitor of the switching power supply, where ESRb is the resistance value of the parallel resistor; Step45: Utilize Find the maximum current of the output capacitor; Step 46: Utilize Calculate The value, while using Calculate the inductance value and use Calculate the time constant; Step 47: According to Reverse the signal of capacitor current during the turn-off phase of the switching transistor; Step 48: Randomly select two moments during the turn-off phase of the switching transistor. and ,use Calculate the capacitance value of the output capacitor.

2. A non-invasive LC-type filter structure online detection system for the output capacitor of a switching power supply, characterized in that, The system includes a memory, a processor, and a non-invasive LC-type filter structure switching power supply output capacitor online detection program stored on the processor. When the processor runs the non-invasive LC-type filter structure switching power supply output capacitor online detection program, it executes the following steps: Step S10: When the switching power supply is operating normally, synchronously acquire the output voltage signal of the switching power supply. Output voltage ripple signal and load current signal ; Step S20: Determine the operating mode of the switching power supply based on the output voltage ripple signal. The operating mode includes DCM mode and CCM mode. If the switching power supply is operating in DCM mode, proceed to step S30. If the switching power supply is operating in CCM mode, proceed to step S40. Step S30: Detect the output capacitor parameters of the switching power supply using the DCM mode detection method; Step S40: Detect the output capacitor parameters of the switching power supply using the CCM mode detection method; Step S50: Determine the operating status of the LC-type filter structure switching power supply based on the detected capacitance value of the switching power supply output capacitor, the standard capacitance value of the capacitor, the resistance value of the equivalent series resistance, and the standard resistance value of the equivalent series resistance. When the processor runs the online detection program for the output capacitor of the non-intrusive LC-type filter structure switching power supply, it also performs the following steps: Step S31: Calculate the slope of the linear change in output voltage ripple during the stage when the inductor current is 0. And then according to Determine the capacitance value of the output capacitor; Step S32: Calculate the duty cycle of the switching transistor in the switching power supply using the output voltage ripple. Duty cycle during which the inductor current is not zero during the switching transistor's off-state phase ,use Calculate the maximum inductor current; Step S33: Utilize Calculate the integral of the capacitor current during the turn-on phase of the switching transistor; Step S34: Utilize Calculate the ESR value of the output capacitor; When the processor runs the online detection program for the output capacitor of the non-intrusive LC-type filter structure switching power supply, it also performs the following steps: Step 41: Connect an RC circuit with known parameters in parallel to the output of the switching power supply, and then collect the output voltage ripple signal of the switching power supply. ; Step 42: Based on the output voltage ripple signal of the switching power supply before the parallel RC circuit. Calculate the duty cycle of the switching power supply. Switching cycle and peak-to-peak output voltage ripple reuse Calculate Size; Step 43: Based on the output voltage ripple signal of the switching power supply after the parallel RC circuit. Find the new duty cycle of the switching power supply. Switching cycle and peak-to-peak output voltage ripple reuse Calculate Size; Step44: Utilize Calculate the ESR value of the output capacitor of the switching power supply, where ESRb is the resistance value of the parallel resistor; Step45: Utilize Find the maximum current of the output capacitor; Step 46: Utilize Calculate The value, while using Calculate the inductance value and use Calculate the time constant; Step 47: According to Reverse the signal of capacitor current during the turn-off phase of the switching transistor; Step 48: Randomly select two moments during the turn-off phase of the switching transistor. and ,use Calculate the capacitance value of the output capacitor.

3. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a non-intrusive LC-type filter structure switching power supply output capacitor online detection program, which, when run by a processor, executes the steps of the method described in claim 1.

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