Dc-dc converter power link health monitoring system and method

Abstract

The application discloses a DCDC converter power link health state monitoring system and method, and belongs to the technical field of power management. sw The system comprises a switch node current sampling module arranged at the front end of an inductor L of the DCDC converter, a load current sampling module arranged at the rear end of the inductor L, and a microcontroller unit (MCU). load The microcontroller unit (MCU) synchronously collects the switch node current I sw The waveform characteristic parameters of the switch node current I sw are analyzed to determine the health state of the DCDC power chip and the peripheral inductor L. The application can realize online diagnosis and early warning of power link parameter degradation, and improves system reliability and safety.

Description

Technical Field

[0001] This invention belongs to the field of power management technology, specifically relating to a power link health status monitoring system and method for DC-DC converters. Background Technology

[0002] In high-power DC-DC converters, monitoring of the output current is typically limited to the load end after the inductor. When the DC-DC chip itself (such as the power switch) or the external inductor experiences parameter degradation or abnormalities, it cannot be detected, making it impossible to monitor the operating status related to the DC-DC power link in real time. Summary of the Invention

[0003] The purpose of this invention is to provide a power link health status monitoring system and method for DC-DC converters. By using a current sampling module located at the front end of the inductor, a current sampling module located at the back end of the inductor, and a microcontroller unit connected to both, the current at the front end and the back end of the inductor is sampled synchronously, and the waveform characteristics of the front end current are analyzed. This enables online diagnosis and early warning of parameter degradation and abnormal operation of the DC-DC power chip and peripheral inductors, effectively solving the problems mentioned in the background art.

[0004] To achieve the above objectives, as one aspect of the present invention, the present invention provides a DC-DC converter power link health status monitoring system, the system comprising:

[0005] The switching node current sampling module is located at the inductor L of the DC-DC converter and is used to collect the switching node current I. sw ;

[0006] The load current sampling module is located at the rear end of the inductor L and is used to collect the load current I. load ;

[0007] The microcontroller unit, connected to the switching node current sampling module and the load current sampling module, is used to synchronously acquire the switching node current I. sw and load current I load And based on the switching node current I sw The waveform characteristic parameters are used to diagnose the health status of the power link of the DC-DC converter.

[0008] Preferably, the switching node current sampling module is a Hall effect current sensor or a low-resistance shunt.

[0009] Preferably, the waveform characteristic parameters include at least one of the following: peak-to-peak value of the switching node current, current rise slope, or effective duty cycle.

[0010] Preferably, the microcontroller unit is further configured to compare the waveform characteristic parameters with a preset threshold or a benchmark model to determine the parameter degradation state of the power switch or inductor L in the DC-DC converter.

[0011] In another aspect, the present invention provides a method for monitoring the health status of a DC-DC converter power link, comprising the following steps:

[0012] Synchronously acquire the switching node current I at the front end of the inductor L of the DC-DC converter sw The load current I at the downstream end of the inductor L load ;

[0013] Extract the switching node current I sw At least one waveform characteristic parameter;

[0014] The health status of the DC-DC converter power link is determined based on the at least one waveform characteristic parameter.

[0015] Preferably, the waveform characteristic parameters include at least one of ripple peak value, current rise slope, or effective duty cycle.

[0016] Preferably, determining the health status of the DC-DC converter power link based on the at least one waveform characteristic parameter specifically includes:

[0017] The waveform characteristic parameters are compared with preset thresholds or benchmark models, and the health status of the DC-DC converter power link is determined based on the comparison results.

[0018] Preferably, the comparison includes: generating an inductor degradation warning when the peak-to-peak value of the ripple exceeds a first preset threshold; and / or generating an abnormal warning for power switch or circuit parameters when the current rise slope deviates from a second preset threshold.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] This invention monitors and analyzes the waveform characteristics (such as ripple peak-to-peak value and rise slope) of the switching node current at the inductor front end of a DC-DC converter. This allows for the timely detection and location of parameter degradation in the DC-DC power link (including internal power switches and external inductors) before significant system performance deterioration. This provides predictive maintenance capabilities for the power system, significantly improving system reliability and safety, and avoiding the risk of system failure due to sudden failure of critical components. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the DC-DC converter power link health status monitoring system in an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram comparing the waveforms of the switching node current and the load current in an embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] A first aspect of the present invention provides a power link health status monitoring system for a DC-DC converter, the system comprising:

[0025] The switching node current sampling module is located at the inductor L of the DC-DC converter and is used to collect the switching node current I. sw ;

[0026] A load current sampling module is located at the rear end of the inductor L and is used to collect the load current Iload;

[0027] A microcontroller unit (MCU) is connected to the switching node current sampling module and the load current sampling module to synchronously acquire the switching node current I. sw and load current I load And based on the switching node current I sw The waveform characteristic parameters are used to diagnose the health status of the power link of the DC-DC converter.

[0028] In this embodiment, the switching node current sampling module is a Hall effect current sensor or a low-resistance shunt.

[0029] In this embodiment, the waveform characteristic parameters include at least one of the peak-to-peak value of the switching node current, the current rise slope, or the effective duty cycle.

[0030] In this embodiment, the microcontroller unit (MCU) is also used to compare the waveform characteristic parameters with a preset threshold or a benchmark model to determine the parameter degradation state of the power switch or inductor L in the DC-DC converter.

[0031] A second aspect of this invention provides a method for monitoring the health status of a DC-DC converter power link, comprising the following steps:

[0032] Synchronously acquire the switching node current I at the front end of the inductor L of the DC-DC converter sw The load current I at the downstream end of the inductor L load ;

[0033] Extract the switching node current Isw At least one waveform characteristic parameter;

[0034] The health status of the DC-DC converter power link is determined based on the at least one waveform characteristic parameter.

[0035] In this embodiment, the waveform characteristic parameters include at least one of ripple peak value, current rise slope, or effective duty cycle.

[0036] In this embodiment, determining the health status of the DC-DC converter power link based on the at least one waveform characteristic parameter specifically includes:

[0037] The waveform characteristic parameters are compared with preset thresholds or benchmark models, and the health status of the DC-DC converter power link is determined based on the comparison results.

[0038] In this embodiment, the comparison includes: generating an inductor degradation warning when the peak-to-peak value of the ripple exceeds a first preset threshold; and / or generating an abnormal warning for power switch or circuit parameters when the current rise slope deviates from a second preset threshold.

[0039] One specific embodiment of the present invention is as follows: Figure 1 As shown, in a classic BUCK DC / DC converter structure, except for the load current I after the inductor L... load In addition to regular sampling, a current sampling module was specially added at the switching node (i.e., the front end of inductor L) to sample the switching node current I in real time. sw .

[0040] By setting up dual sampling points, the microcontroller unit (MCU) can obtain two key pieces of information: 1) the average load current value I from the load end. load ;2) Current waveform I from the switching node sw The MCU controls I... sw By analyzing the waveform, its characteristic parameters can be extracted, such as the peak-to-peak value of the ripple current ΔI. sw Current rise slope and effective duty cycle, etc.

[0041] The fault diagnosis principle of this invention is based on the fundamental operating equations of a switching power supply in continuous conduction mode (CCM). For a BUCK converter, the switching node voltage I... sw ripple peak value ΔI sw The theoretical value is ΔI sw = V out * (1 - D) / (L * f sw ), where V out Where D is the output voltage, D is the duty cycle, L is the inductance value, and f is the output voltage. swThis is the switching frequency. In V out f sw Given and the load current I load Under constant steady-state conditions, ΔI sw It is inversely proportional to the inductance value L. Therefore, ΔI is detected. sw A significant increase in current indicates a direct inference that the inductance L has decreased (e.g., magnetic saturation). Similarly, the theoretical value of the current rise slope di / dt is (V in - V out The abnormal changes in ) / L can be correlated with the input voltage V in The change in inductor L or the on-state voltage drop of the power switch. The microcontroller unit compares this with the real-time extracted ΔI. sw By combining characteristic parameters such as di / dt with the health threshold or benchmark model preset based on the above theoretical model, quantitative diagnosis can be achieved.

[0042] At load current I load Under constant (or known) conditions, the switching node current I sw The waveform characteristics have a definite correspondence with the health status of the DC-DC power link, such as... Figure 2 As shown. As a specific diagnostic example: when the inductance of inductor L decreases due to core saturation, aging, or manufacturing defects, at the same switching frequency and load current I... load Under these conditions, the microcontroller unit (MCU) will monitor I sw The peak-to-peak value of the waveform ΔI sw Significantly increased (according to the formula ΔI) sw ∝ 1 / L). The diagnostic algorithm built into the microcontroller unit (MCU) will compare the real-time acquired ΔI. sw The inductor is compared with a preset normal ripple threshold to determine whether it has degraded, thereby achieving early warning.

[0043] As another specific diagnostic example: when the on-resistance R of the power switch transistor decreases due to aging... ds(on) When the voltage increases, at the same input voltage V in Under certain load conditions, the effective voltage applied across inductor L will decrease during switch conduction. The microcontroller unit will monitor the switching node current I. sw The current rise rate decreases. Simultaneously, to maintain stable output voltage, the control system may increase the duty cycle D. The microcontroller unit (MCU) can combine these two correlated characteristics—a decreased current rise rate and an increased duty cycle detected or detected by control feedback—to determine if the power switch may be degrading.

[0044] This invention, by monitoring and analyzing the waveform characteristics of the switching node current at the inductor front end of a DC-DC converter, can promptly detect and locate parameter degradation in the DC-DC power link before significant system performance deteriorates. This provides predictive maintenance capabilities for power systems, significantly improving system reliability and safety.

[0045] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A DCDC converter power link health monitoring system, characterized by, The system comprises: a switching node current sampling module arranged at the front end of an inductor L of a DCDC converter, for collecting a switching node current Isw; a load current sampling module arranged at the rear end of the inductor L, for collecting a load current Iload; a microcontroller unit connected with the switching node current sampling module and the load current sampling module, for synchronously acquiring the switching node current Isw and the load current Iload, and diagnosing a health state of a power link of the DCDC converter based on waveform characteristic parameters of the switching node current Isw; the waveform characteristic parameters comprise at least one of a ripple peak-to-peak value, a current rise slope or an effective duty cycle; the microcontroller unit compares the waveform characteristic parameters with preset threshold values or a reference model, generates an inductor degradation early warning when the ripple peak-to-peak value exceeds a first preset threshold value, and / or generates a power switch tube or circuit parameter abnormality early warning when the current rise slope deviates from a second preset threshold value.

2. The DCDC converter power link health monitoring system of claim 1, wherein, The switching node current sampling module is a Hall effect current sensor or a low-resistance shunt.

3. A method for monitoring the health status of a DCDC converter power link, characterized in that, The method comprises the following steps: synchronously collecting a switching node current Isw at the front end of an inductor L of a DCDC converter and a load current Iload at the rear end of the inductor L; extracting at least one waveform characteristic parameter of the switching node current Isw; judging a health state of a power link of the DCDC converter based on the at least one waveform characteristic parameter; the waveform characteristic parameters comprise at least one of a ripple peak-to-peak value, a current rise slope or an effective duty cycle; comparing the waveform characteristic parameters with preset threshold values or a reference model, generating an inductor degradation early warning when the ripple peak-to-peak value exceeds a first preset threshold value; and / or generating a power switch tube or circuit parameter abnormality early warning when the current rise slope deviates from a second preset threshold value.

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