Method, system and medium for detecting pwm drive failure of dc-dc product

Abstract

This invention relates to the field of DC-DC product testing technology, and discloses a method, system, and medium for detecting PWM drive failure in DC-DC products. The method includes: powering on the DC-DC product; determining whether the DC-DC product is in constant voltage or constant current mode; if in constant voltage mode, determining whether the PWM drive is abnormal by detecting the actual output voltage change and voltage loop output; if in constant current mode, determining whether the PWM drive is abnormal by detecting the actual current change and current loop output; when the PWM drive is determined to be abnormal, acquiring the PWM duty cycle value of the control loop output; acquiring the feedback value of the closed-loop control according to different operating modes; and combining the PWM duty cycle value and the feedback value to determine whether the PWM drive has failed. This invention can achieve PWM drive failure detection for DC-DC products, and the detection results are scientific, accurate, and reliable.

Description

Technical Field

[0001] This invention relates to the field of DC-DC product testing technology, and in particular to a method, system, and medium for detecting PWM drive failure in DC-DC products. Background Technology

[0002] Clean and green electricity plays an increasingly important role in modern society's production and daily life, and power electronic products are a crucial component of green energy systems. DC-DC (Direct Current to Direct Current) converters, which convert DC voltage, are widely used power electronic products. The functionality of power electronic products is primarily achieved through the on / off control of power semiconductor devices. This control is achieved using pulse width modulation (PWM) drive signals. However, under prolonged and high-load operating conditions, PWM drives may malfunction. Therefore, failure detection of the PWM drive in DC-DC products is extremely important.

[0003] Typically, PWM drive signals originate from the chip control output, pass through a level conversion isolation chip, drive circuit, and drive wiring harness before finally reaching the driven device. The level undergoes several conversions, and the signals are usually not on a single circuit board. This places demands on the stability and reliability of failure detection methods: they must effectively ensure that normal functionality is not affected while accurately and effectively identifying abnormal situations. However, existing failure detection methods for PWM drives are often overlooked during the product design phase. Actual failure detection requires adding a series of hardware detection circuits, increasing product design complexity and cost, resulting in resource waste and redundant design. To reduce hardware costs, some approaches utilize software design for failure detection; however, there is currently no effective failure detection method for PWM drives in DC-DC products. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method, system and medium for detecting PWM drive failure of DC-DC products, which can realize the detection of PWM drive failure of DC-DC products, and the detection results are scientific, accurate and reliable.

[0005] To address the aforementioned technical problems, this invention provides a method for detecting PWM drive failure in DC-DC products, comprising: When the DC-DC product is powered on, determine whether the DC-DC product is in constant voltage mode or constant current mode. If it is in constant voltage mode, determine whether the PWM drive is abnormal by detecting the actual output voltage change and voltage loop output. If it is in constant current mode, determine whether the PWM drive is abnormal by detecting the actual current change and current loop output. When a PWM drive malfunction is detected, the PWM duty cycle value of the control loop output is obtained, and the feedback value of the closed-loop control is obtained according to different operating modes. The PWM duty cycle value and the feedback value are combined to determine whether the PWM drive has failed.

[0006] Furthermore, the method of determining whether the PWM drive is abnormal by detecting the actual output-side voltage change and voltage loop output includes: The voltage ratio is calculated based on the different voltage changes under constant voltage mode, and the PWM drive is periodically determined to be abnormal based on the voltage ratio and the output of the PI regulator in the voltage loop. The voltage determination condition is: RatioVolt (k) – RatioVolt (k-1) <Ratio and VoltLoopOut(k)<VoltLoopMax, In the formula, RatioVolt(k) represents the voltage ratio in the k-th cycle, Ratio represents the voltage ratio change threshold, VoltLoopOut(k) represents the output of the PI regulator in the voltage loop in the k-th cycle, and VoltLoopMax represents the voltage loop output limit. When the voltage determination condition is met, the PWM drive is determined to be abnormal.

[0007] Furthermore, the specific output limit value of the voltage loop is as follows: VoltLoopMax=a×Min(Isat, IcurrentMax), In the formula, a is the safety margin coefficient, Min() means taking the minimum value, Isat represents the maximum saturation current of the power inductor in the product circuit, and IcurrentMax represents the maximum allowable current of the switching transistor.

[0008] Furthermore, the method of determining whether the PWM drive is abnormal by detecting the actual change in current value and the current loop output includes: Calculate the absolute value of the current change rate, and periodically determine whether the PWM drive is abnormal based on the absolute value of the current change rate and the current loop output. The current determination condition is: abs(il(k)) – abs(il(k-1))<current and CurrentLoopOut(k)<CurrentLoopMax, In the formula, il(k) represents the inductor current value in the k-th cycle of the circuit, abs() represents taking the absolute value, current represents the current change threshold, CurrentLoopOut(k) represents the current loop output in the k-th cycle, and CurrentLoopMax represents the current loop output limit value. When the current determination condition is met, the PWM drive is determined to be abnormal.

[0009] Furthermore, the specific output limit value of the current loop is as follows: CurrentLoopMax = TpwmMax×b, In the formula, b represents the safety threshold coefficient, and TpwmMax represents the theoretical maximum duty cycle value.

[0010] Furthermore, the method for calculating the theoretical maximum duty cycle is as follows: TpwmMax = (Cycle Time - Dead Time) / Cycle Time.

[0011] Furthermore, before determining whether the DC-DC product is in constant voltage mode or constant current mode, a detection time window is set, and the DC-DC product is then determined to be in constant voltage mode or constant current mode after the detection time window has elapsed.

[0012] Furthermore, the PWM drive failure is determined by combining the PWM duty cycle value and the feedback value, specifically as follows: The failure determination condition is set as follows: CtrlLoopOut(k)- CtrlLoopOut(k-1)>0、 feedback(k)- feedback(k-1) =0 and feedback(k) →0, In the formula, CtrlLoopOut(k) represents the PWM duty cycle value in the k-th cycle, feedback(k) represents the feedback value of the closed-loop control in the k-th cycle, and → indicates approaching; When the failure determination condition is met and continues for a period of time, the PWM drive is determined to be faulty.

[0013] This invention also provides a PWM drive failure detection system for DC-DC products, comprising: Product startup module, used to power on DC-DC products; The PWM drive anomaly determination module is used to determine whether the DCDC product is in constant voltage mode or constant current mode. If it is in constant voltage mode, it determines whether the PWM drive is abnormal by detecting the actual output voltage change and voltage loop output. If it is in constant current mode, it determines whether the PWM drive is abnormal by detecting the actual current value change and current loop output. The PWM drive failure determination module is used to obtain the PWM duty cycle value of the control loop output when the PWM drive is determined to be abnormal, obtain the feedback value of the closed loop control according to different operating modes, and determine whether the PWM drive has failed by combining the PWM duty cycle value and the feedback value.

[0014] The present invention also provides a PWM drive failure detection medium for DC-DC products, on which a computer program is stored, which, when executed by a processor, implements the PWM drive failure detection method for DC-DC products.

[0015] Compared with the prior art, the above-described technical solution of the present invention has the following advantages: This invention determines whether the PWM drive is abnormal during the startup process of a DC-DC product by using different operating modes. Based on this, it obtains the feedback value of the closed-loop control according to different operating modes, and combines the PWM duty cycle value and the feedback value to comprehensively determine whether the PWM drive has failed. This achieves PWM drive failure detection for DC-DC products, and the detection results are scientific, accurate, and reliable. Attached Figure Description

[0016] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a flowchart of a method in a preferred embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the control topology for PWM driving of a DC-DC product in a preferred embodiment of the present invention. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0019] Reference Figure 1 As shown, this invention discloses a method for detecting PWM drive failure in DC-DC products, comprising the following steps: S1: Power on the DCDC product, set the detection time window, and execute S2 after the detection time window has elapsed.

[0020] like Figure 2 The diagram shows the topology of the PWM drive control loop for a DC-DC product. The PWM drive signal is emitted from the PWM module of the microcontroller unit (MCU), and is finally transmitted to the controlled devices Q1, Q2, Q3, and Q4 through the drive harness and drive circuit. The input voltage (Vin), output voltage (Vout), and inductor current sampling signal (il) in the control loop are also fed back to the MCU's ADC (Analog-to-Digital Converter) module.

[0021] Before startup, the sampling feedback is 0. If a large output and small feedback are detected immediately upon startup, the normal soft-start process may be mistakenly judged as a failure. Therefore, a detection time window is set. In this embodiment, the detection time window is set to 10ms. Failure detection is not performed in the first 10ms after startup to prevent false alarms from affecting normal startup and further ensure the safe and stable operation of the DC-DC product.

[0022] S2: Determine whether the DC-DC product is operating in constant voltage or constant current mode; if it is constant voltage mode, execute S3; if it is constant current mode, execute S4.

[0023] S3: Determine whether the PWM drive is abnormal by detecting the actual output voltage change and voltage loop output.

[0024] S3-1: Calculate the voltage ratio based on the different voltage changes under constant voltage mode.

[0025] To determine whether the bridge arm is operating in a step-down or step-up mode, if it is in a constant-voltage step-down mode, the voltage ratio is: RatioVolt = Vin / Vout; Under constant voltage boost conditions, the voltage ratio is: RatioVolt = Vout / Vin; In the formula, RatioVolt represents the voltage ratio, Vin represents the input voltage, and Vout represents the output voltage.

[0026] S3-2: Set the voltage determination condition as follows: RatioVolt (k) – RatioVolt (k-1) <Ratio and VoltLoopOut(k)<VoltLoopMax, In the formula, RatioVolt(k) represents the voltage ratio in the k-th cycle, Ratio represents the threshold value of the voltage ratio change, VoltLoopOut(k) represents the output of the PI regulator in the voltage loop in the k-th cycle, and VoltLoopMax represents the output limit value of the voltage loop. Under normal circumstances, as VoltLoopOut gradually increases, RatioVolt(k) – RatioVolt(k-1) should be increasing. If the PWM drive fails, Ratio will approach zero infinitely. Considering the sampling error factor, Ratio is set to 0.5% in this embodiment.

[0027] In the voltage and current dual closed-loop control circuit, the output of the PI regulator in the voltage loop is actually the setpoint of the inner current loop. Limiting the PI output of the voltage loop is to limit the reference current of the inductor in the circuit, preventing excessive current from damaging the switching transistor or inductor. Based on the minimum value Min(Isat, IcurrentMax) of the maximum saturation current (Isat) of the power inductor and the maximum allowable current IcurrentMax of the switching transistor in the product circuit, the voltage loop output limit value is set as follows: VoltLoopMax=a×Min(Isat, IcurrentMax), In the formula, a is the safety margin coefficient, a=0.85 in this embodiment, Min() means taking the minimum value, Isat means the maximum saturation current of the power inductor in the product circuit, and IcurrentMax means the maximum allowable current of the switching transistor.

[0028] S3-3: Based on the voltage ratio and the output of the PI regulator in the voltage loop, the PWM drive is periodically judged to be abnormal. When the voltage judgment condition is met, it indicates that both the voltage ratio and the output of the PI regulator in the voltage loop are abnormal, and the PWM drive is judged to be abnormal. By using dual indicators for judgment and periodic accumulation, the risk of misjudgment can be effectively avoided.

[0029] S4: Determine if the PWM drive is abnormal by detecting the actual change in current value and the current loop output.

[0030] S4-1: In constant current mode, the current value can be positive or negative. Calculate the absolute change rate of the current.

[0031] S4-2: Set the current determination condition as follows: abs(il(k)) – abs(il(k-1))<current and CurrentLoopOut(k)<CurrentLoopMax, In the formula, il(k) represents the inductor current value in the k-th cycle of the circuit, abs() represents taking the absolute value, current represents the current change threshold, CurrentLoopOut(k) represents the current loop output in the k-th cycle, and CurrentLoopMax represents the current loop output limit value. Under normal operating conditions, the current value continuously increases and gradually approaches the constant current target value. If the PWM drive fails, abs(il(k)) – abs(il(k-1)) will infinitely approach zero. Considering the sampling error factor, current=0.5% is set in this embodiment.

[0032] Since the current loop output value directly affects the duty cycle, CurrentLoopMax is the maximum effective duty cycle value. Considering the dead time of the upper and lower bridge arms of the DC-DC circuit, the specific current loop output limit value is as follows: CurrentLoopMax = TpwmMax×b, In the formula, b represents the safety threshold coefficient, and in this embodiment, b = 95%. TpwmMax represents the theoretical maximum duty cycle value.

[0033] The theoretical maximum duty cycle is calculated as follows: TpwmMax = (Cycle Time - Dead Time) / Cycle Time.

[0034] S4-3: The PWM drive is periodically checked for abnormality based on the absolute rate of change of the current and the current loop output. When the current determination condition is met, it indicates that both the absolute rate of change of the current and the current loop output are abnormal, thus determining that the PWM drive is abnormal. By using dual indicators for determination and periodic accumulation, the risk of misjudgment can be effectively avoided.

[0035] S5: When the PWM drive is determined to be abnormal, obtain the PWM duty cycle value of the control loop output, obtain the feedback value of the closed loop control according to different operating modes, and combine the PWM duty cycle value and the feedback value to determine whether the PWM drive has failed.

[0036] S5-1: When a PWM drive anomaly is detected, the PWM duty cycle value output by the control loop is obtained, and the feedback value of the closed-loop control is obtained according to different operating modes. Specifically, the feedback value of the closed-loop control is obtained according to different operating modes as follows: if it is a constant voltage mode, the sampled voltage value is used as the feedback value of the closed-loop control; if it is a constant current mode, the sampled current value is used as the feedback value of the closed-loop control.

[0037] S5-2: Set the failure determination condition as follows: CtrlLoopOut(k)- CtrlLoopOut(k-1)>0、 feedback(k)- feedback(k-1) =0 and feedback(k) →0, In the formula, CtrlLoopOut(k) represents the PWM duty cycle value in the k-th cycle, feedback(k) represents the feedback value of the closed-loop control in the k-th cycle, → indicates that it approaches; CtrlLoopOut(k) - CtrlLoopOut(k-1) > 0 indicates that the PWM duty cycle value continues to increase at this time, feedback(k) - feedback(k-1) = 0 indicates that the feedback value of the closed-loop control remains unchanged, and feedback(k) → 0 indicates that the feedback value of the closed-loop control is very small.

[0038] S5-3: When the failure determination condition is met and continues for a period of time (the duration is adjusted according to the actual situation), the PWM drive is determined to be faulty.

[0039] Because power electronic closed-loop systems primarily employ negative feedback regulation, if a problem occurs in a component of the PWM control loop (such as sampling failure, poor contact in the drive harness, abnormal drive circuitry, or an abnormality in the controlled device itself), the PWM duty cycle (CtrlLoopOut) output by the software control loop changes, but the power stage circuit does not activate. This results in the feedback value of the closed-loop control (i.e., the output voltage or current) being 0 or extremely small. The error at this point is given by error(k) = object - feedback(k), where error(k) represents the error in the k-th cycle, object is the given target value, and feedback(k) represents the feedback value of the closed-loop control in the k-th cycle. It can be seen that error(k) is infinitely close to the feedback value, which is a significant error. The integrator in the PI controller will begin accumulating this error. Because the feedback remains very small, the integrator will continue to accumulate, attempting to output CtrlLoopOut to compensate for this error. Therefore, in a failed state, CtrlLoopOut will quickly jump to the set VoltLoopMax or CurrentLoopMax and stop there, while the feedback value remains very small, affecting the determination of PWM drive failure. To solve this problem, this embodiment sets a failure determination condition. Only when the failure determination condition is met and lasts for a period of time is the PWM drive determined to be failed. By accumulating a counter instead of triggering immediately, misjudgments of instantaneous states caused by noise or sudden load changes are avoided.

[0040] This invention also discloses a PWM drive failure detection system for DC-DC products, comprising: Product startup module, used to power on DC-DC products; The PWM drive anomaly determination module is used to determine whether the DCDC product is in constant voltage mode or constant current mode. If it is in constant voltage mode, it determines whether the PWM drive is abnormal by detecting the actual output voltage change and voltage loop output. If it is in constant current mode, it determines whether the PWM drive is abnormal by detecting the actual current value change and current loop output. The PWM drive failure determination module is used to obtain the PWM duty cycle value of the control loop output when the PWM drive is determined to be abnormal, obtain the feedback value of the closed loop control according to different operating modes, and determine whether the PWM drive has failed by combining the PWM duty cycle value and the feedback value.

[0041] The present invention also discloses a PWM drive failure detection medium for DC-DC products, which stores a computer program. When the computer program is executed by a processor, it implements a PWM drive failure detection method for DC-DC products.

[0042] The present invention also discloses a PWM drive failure detection device for DC-DC products, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a PWM drive failure detection method for DC-DC products.

[0043] This invention determines whether the PWM drive is abnormal during the startup process of a DC-DC product by using different operating modes. Based on this, it obtains the feedback value of the closed-loop control according to different operating modes, and combines the PWM duty cycle value and the feedback value to comprehensively determine whether the PWM drive has failed. This achieves PWM drive failure detection for DC-DC products, and the detection results are scientific, accurate, and reliable.

[0044] Traditional power electronic products often fail to display the cause of PWM drive malfunctions due to insufficient diagnostic methods in their PWM diagnostic functions, making troubleshooting difficult. This invention compares the rate of change of the control loop output value with the changes in the control loop feedback value during product startup and operation, and samples the rate of change of voltage or current in the control loop in real time. When subsequent voltage or current judgment conditions are met, the invention further uses real-time sampled voltage and current feedback values ​​to comprehensively determine whether the PWM drive has failed, thus enabling accurate and rapid troubleshooting and repair.

[0045] This invention enables effective identification of PWM drive failures without adding hardware components or circuits, greatly facilitating the troubleshooting of PWM drive problems. It allows for rapid and accurate problem identification during product debugging, significantly improving debugging efficiency. In mass production, it enables rapid inspection of the PWM drive circuit and drive harness, optimizing production efficiency. During after-sales maintenance, it provides accurate fault display, greatly facilitating after-sales personnel in pinpointing problem areas and quickly resolving issues, improving product maintainability and user experience. In practical applications, it allows for the detection of potential anomalies before product operation, preventing more serious failures and effectively ensuring product reliability.

[0046] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0047] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0048] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0049] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0050] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for detecting PWM drive failure in a DC-DC product, characterized in that, include: When the DC-DC product is powered on, determine whether the DC-DC product is in constant voltage mode or constant current mode. If it is in constant voltage mode, determine whether the PWM drive is abnormal by detecting the actual output voltage change and voltage loop output. If it is in constant current mode, determine whether the PWM drive is abnormal by detecting the actual current change and current loop output. When a PWM drive malfunction is detected, the PWM duty cycle value of the control loop output is obtained, and the feedback value of the closed-loop control is obtained according to different operating modes. The PWM duty cycle value and the feedback value are combined to determine whether the PWM drive has failed.

2. The PWM drive failure detection method for DC-DC products according to claim 1, characterized in that: The method of determining whether the PWM drive is abnormal by detecting the actual output-side voltage change and voltage loop output includes: The voltage ratio is calculated based on the different voltage changes under constant voltage mode, and the PWM drive is periodically determined to be abnormal based on the voltage ratio and the output of the PI regulator in the voltage loop. The voltage determination condition is: RatioVolt (k) – RatioVolt (k-1) <Ratio and VoltLoopOut(k)<VoltLoopMax, In the formula, RatioVolt(k) represents the voltage ratio in the k-th cycle, Ratio represents the voltage ratio change threshold, VoltLoopOut(k) represents the output of the PI regulator in the voltage loop in the k-th cycle, and VoltLoopMax represents the voltage loop output limit. When the voltage determination condition is met, the PWM drive is determined to be abnormal.

3. The PWM drive failure detection method for DC-DC products according to claim 2, characterized in that: The specific output limit value of the voltage loop is as follows: VoltLoopMax=a×Min(Isat, IcurrentMax), In the formula, a is the safety margin coefficient, Min() means taking the minimum value, Isat represents the maximum saturation current of the power inductor in the product circuit, and IcurrentMax represents the maximum allowable current of the switching transistor.

4. The PWM drive failure detection method for DC-DC products according to claim 1, characterized in that: The method of determining whether the PWM drive is abnormal by detecting the actual change in current value and the current loop output includes: Calculate the absolute value of the current change rate, and periodically determine whether the PWM drive is abnormal based on the absolute value of the current change rate and the current loop output. The current determination condition is: abs(il(k)) – abs(il(k-1))<current and CurrentLoopOut(k)<CurrentLoopMax, In the formula, il(k) represents the inductor current value in the k-th cycle of the circuit, abs() represents taking the absolute value, current represents the current change threshold, CurrentLoopOut(k) represents the current loop output in the k-th cycle, and CurrentLoopMax represents the current loop output limit value. When the current determination condition is met, the PWM drive is determined to be abnormal.

5. The PWM drive failure detection method for DC-DC products according to claim 4, characterized in that: The specific output limit value of the current loop is as follows: CurrentLoopMax = TpwmMax×b, In the formula, b represents the safety threshold coefficient, and TpwmMax represents the theoretical maximum duty cycle value.

6. The PWM drive failure detection method for DC-DC products according to claim 5, characterized in that: The method for calculating the theoretical maximum duty cycle is as follows: TpwmMax = (Cycle Time - Dead Time) / Cycle Time.

7. The PWM drive failure detection method for DC-DC products according to claim 1, characterized in that: Before determining whether the DC-DC product is in constant voltage or constant current mode, a detection time window is set, and the DC-DC product is then determined to be in constant voltage or constant current mode after the detection time window has elapsed.

8. The PWM drive failure detection method for DC-DC products according to claim 1, characterized in that: The determination of whether the PWM drive has failed is based on the PWM duty cycle value and the feedback value, specifically as follows: The failure determination condition is set as follows: CtrlLoopOut(k)- CtrlLoopOut(k-1)> 0, feedback(k)- feedback(k-1) =0 and feedback(k) →0, In the formula, CtrlLoopOut(k) represents the PWM duty cycle value in the k-th cycle, feedback(k) represents the feedback value of the closed-loop control in the k-th cycle, and → indicates approaching; When the failure determination condition is met and continues for a period of time, the PWM drive is determined to be faulty.

9. A PWM drive failure detection system for DC-DC products, characterized in that, include: Product startup module, used to power on DC-DC products; The PWM drive anomaly determination module is used to determine whether the DCDC product is in constant voltage mode or constant current mode. If it is in constant voltage mode, it determines whether the PWM drive is abnormal by detecting the actual output voltage change and voltage loop output. If it is in constant current mode, it determines whether the PWM drive is abnormal by detecting the actual current value change and current loop output. The PWM drive failure determination module is used to obtain the PWM duty cycle value of the control loop output when the PWM drive is determined to be abnormal, obtain the feedback value of the closed loop control according to different operating modes, and determine whether the PWM drive has failed by combining the PWM duty cycle value and the feedback value.

10. A PWM drive failure detection medium for a DC-DC product, wherein a computer program is stored thereon, characterized in that: When executed by a processor, the computer program implements the PWM drive failure detection method for DC-DC products as described in any one of claims 1-8.

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