Method and apparatus for detecting drive failure of an acdc power supply system, and electronic device

Abstract

This invention provides a method, apparatus, and electronic device for detecting drive faults in AC / DC power systems, relating to the field of power electronics technology. The method includes: acquiring the uncontrolled rectified voltage of the rectifier circuit as a reference voltage; acquiring the desired DC-side bus voltage and the actual AC-side bus voltage; and determining whether the rectifier circuit's drive is faulty based on a first deviation between the desired DC-side bus voltage and the actual AC-side bus voltage, and a second deviation between the desired DC-side bus voltage and the reference voltage. This invention utilizes the uncontrolled rectified voltage of the rectifier circuit as a reference, combined with the desired DC-side bus voltage and the actual AC-side bus voltage for comprehensive judgment. It can accurately identify drive faults without additional hardware circuitry, effectively avoiding misjudgments caused by sampling errors or communication failures, and improving the reliability and safety of AC / DC power systems.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a method, apparatus and electronic device for detecting drive faults in an AC / DC power supply system. Background Technology

[0002] Currently, Vienna rectifier topologies (such as AC / DC power systems) are commonly used in AC / DC power systems. Figure 1 (As shown) This is used as the AC-side circuit in conjunction with the subsequent DC / DC converter circuit. The DC / DC converter circuit typically adopts the following... Figure 2 The LLC topology shown is an example. The Vienna topology has advantages such as low input current distortion, high power factor, and low voltage stress on the switching transistors. Under normal operating conditions, the Vienna rectifier circuit achieves boost rectification by controlling the on / off state of the switching transistors, converting the input AC power into a stable DC bus voltage output to supply subsequent circuits.

[0003] However, in actual operation, the drive circuit of the Vienna rectifier circuit may malfunction, such as loss of drive signal, drive circuit failure, or damage to the power switch. When a drive malfunction occurs, the switch cannot operate normally, and the Vienna rectifier circuit will enter an uncontrolled rectification state. At this time, the DC bus voltage will drop to a specific multiple of the peak value of the input phase voltage (e.g., approximately √6 times the effective value of the input phase voltage), which is usually lower than the expected DC bus voltage required for normal operation of the subsequent circuits. If this drive fault cannot be detected in time, the subsequent DC / DC circuit will operate under abnormal input voltage conditions for a long time, leading to severe overheating or even damage to the devices, seriously affecting the reliability and safety of the system. In existing technologies, additional hardware detection circuits are usually used to monitor the drive signal, which increases the cost and complexity of the system and may not be effective in identifying certain soft faults (such as insufficient drive capability). Therefore, there is an urgent need for a detection scheme that can accurately identify drive faults without additional hardware costs. Summary of the Invention

[0004] This invention provides a method, apparatus, and electronic device for detecting drive faults in ACDC power systems, in order to solve the problem that drive faults on the rectifier side of ACDC power systems are difficult to detect in a timely manner, leading to abnormal operation of subsequent circuits.

[0005] In a first aspect, embodiments of the present invention provide a method for detecting drive faults in an AC / DC power supply system, comprising: acquiring the uncontrolled rectified voltage of the rectifier circuit as a reference voltage; acquiring the desired DC-side bus voltage and the actual AC-side bus voltage; and determining whether the drive of the rectifier circuit is faulty based on a first deviation between the desired DC-side bus voltage and the actual AC-side bus voltage, and a second deviation between the desired DC-side bus voltage and the reference voltage.

[0006] In one possible implementation, determining whether the rectifier circuit is driving a fault includes: determining a driving fault in response to the first deviation being greater than a first preset threshold and the second deviation being less than a second preset threshold.

[0007] In one possible implementation, the first preset threshold value ranges from 20V to 40V, and the second preset threshold value ranges from 20V to 40V.

[0008] In one possible implementation, obtaining the uncontrolled rectified voltage of the rectifier circuit as a reference voltage includes: calculating the reference voltage based on the input voltage; wherein the input voltage is the mains voltage.

[0009] In one possible implementation, calculating the reference voltage based on the input voltage includes: determining the reference voltage as the square root of 6 times the input voltage.

[0010] In one possible implementation, the method further includes: performing a protection action in response to determining a drive fault; wherein the protection action includes at least one of shutdown, alarm, or switching to a backup circuit.

[0011] In one possible implementation, the method is executed during the power system startup phase.

[0012] Secondly, embodiments of the present invention provide a drive fault detection device for an ACDC power system, comprising: The reference voltage acquisition module is configured to acquire the uncontrolled rectified voltage of the rectifier circuit as a reference voltage; The desired bus voltage acquisition module is configured to acquire the desired bus voltage on the DC side. The actual bus voltage acquisition module is configured to acquire the actual bus voltage on the AC side. The fault diagnosis module is configured to determine whether the drive of the rectifier circuit is faulty based on a first deviation between the expected DC bus voltage and the actual AC bus voltage, and a second deviation between the expected DC bus voltage and the reference voltage.

[0013] In one possible implementation, the reference voltage acquisition module includes a calculation unit configured to calculate the reference voltage based on an input voltage; wherein the input voltage is the mains voltage.

[0014] Thirdly, embodiments of the present invention provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in the first aspect or any possible implementation thereof.

[0015] In this embodiment of the invention, by introducing the uncontrolled rectified voltage of the rectifier circuit as a reference, and combining the expected bus voltage on the DC side and the actual bus voltage on the AC side for comprehensive judgment, the physical characteristic that the bus voltage will drop to the level of the uncontrolled rectified voltage when the rectifier circuit fails to drive is utilized. The drive fault can be accurately located without additional hardware circuits, avoiding misjudgment caused by sampling errors or communication failures, and effectively protecting the power supply system and downstream loads. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the AC side circuit in an AC / DC power supply system; Figure 2 This is a schematic diagram of the DC side circuit in an AC / DC power supply system; Figure 3 This is an application scenario diagram of the drive fault detection method for ACDC power systems provided in an embodiment of the present invention; Figure 4 This is a flowchart illustrating the implementation of a drive fault detection method for an ACDC power system according to an embodiment of the present invention. Figure 5 This is a flowchart illustrating a drive fault detection method for an ACDC power system provided in another embodiment of the present invention; Figure 6 This is a schematic diagram of the drive fault detection device for an ACDC power system provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0017] like Figure 3 This is an application scenario diagram of the drive fault detection method for ACDC power systems provided in the embodiments of this application, such as... Figure 3 As shown, the transmission between Vienna and LLC is via SCI communication. Vienna's output is the LLC's input, and this voltage is usually referred to as the bus voltage. The specific bus voltage requirement is determined by the downstream LLC network. That is, when the LLC output voltage changes, it will use SCI communication to tell the AC side how much bus voltage should be output.

[0018] The AC side can be understood as a boost circuit. When the driver transistor is not emitting a waveform, the output voltage is 6 times the average value of the input phase voltage. Taking a mains input of 220V as an example, the Vienna bus voltage is 539V. This voltage is called the uncontrolled rectified voltage. This voltage will also cause the LLC to work with a certain load. However, since this bus voltage is not the input voltage expected by the LLC, it will cause the LLC network to work in an abnormal state, resulting in problems such as device overheating. Since the hardware circuit does not detect abnormal operation of the driver transistor, in actual operation, the abnormality of the Vienna driver transistor will go undetected, causing the LLC to work abnormally for a long time. This invention aims to use a software strategy to deal with this problem. The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] Figure 4 The flowchart illustrates the implementation of the drive fault detection method for an ACDC power system provided in this embodiment of the invention. Figure 4 As shown, it includes the following steps: S401 obtains the uncontrolled rectified voltage of the rectifier circuit as a reference voltage.

[0020] The uncontrolled rectified voltage refers to the DC voltage output by the rectifier circuit when it relies solely on natural commutation of its internal diodes without any driving force. A rectifier circuit is a power conversion circuit used to convert alternating current (AC) to direct current (DC), and its topology can be a three-phase full-bridge rectifier circuit, a Vienna rectifier circuit, or other rectifier topologies with similar characteristics. This invention primarily uses a Vienna rectifier circuit as an example for illustration.

[0021] The undriven state refers to a rectifier circuit where all controllable switching devices are off, and the circuit relies solely on passive components for natural commutation. In this state, the output voltage of the rectifier circuit is determined by the amplitude of the input voltage and the inherent topology of the circuit, and does not fluctuate with changes in the control signal, thus exhibiting high predictability. For example, in a three-phase rectifier system, this reference voltage typically has a fixed mathematical relationship with the peak value of the input line voltage. By obtaining this reference voltage, the system establishes a reference coordinate system reflecting the physical limit state of "complete drive failure."

[0022] S402, obtain the desired DC-side bus voltage and the actual AC-side bus voltage.

[0023] The DC-side target bus voltage refers to the DC bus target voltage value set by the ACDC power system based on the downstream load requirements or control objectives. This voltage value is usually calculated by the system controller based on actual operating conditions, or fed back to the upstream rectifier side by the downstream DC / DC converter through a communication interface, reflecting the bus voltage level that the system should achieve under normal driving conditions.

[0024] For example, in charging pile applications, the desired DC bus voltage may be determined by the gain requirements of the subsequent LLC converter; in motor drive applications, this voltage may be determined by the bus voltage setpoint. The actual AC bus voltage refers to the DC bus voltage value actually output by the rectifier circuit at the current moment. This voltage value is usually detected in real time by a voltage sampling circuit set at the output of the rectifier circuit. Obtaining the desired DC bus voltage is to establish the "ideal target" of system operation, while obtaining the actual AC bus voltage is to reflect the "real state" of system operation.

[0025] S403 determines whether the rectifier circuit drive is faulty based on the first deviation between the expected DC bus voltage and the actual AC bus voltage, and the second deviation between the expected DC bus voltage and the reference voltage.

[0026] This is the core judgment logic of the present invention. Specifically, when the rectifier circuit driver fails, the rectifier circuit will lose its boost or voltage regulation control capability, and its actual AC bus voltage will drop from the higher expected DC bus voltage to near the uncontrolled rectified voltage. At this time, the actual AC bus voltage will be significantly lower than the expected DC bus voltage, with a significant first deviation between the two; at the same time, since the input power supply is usually normal, the actual AC bus voltage will be close to the reference voltage, that is, there may be a large second deviation between the expected DC bus voltage and the reference voltage, or the deviation between the actual AC bus voltage and the reference voltage may be extremely small.

[0027] This invention, through comprehensive analysis of the first and second deviations, can accurately identify this specific voltage drop pattern. Unlike simple voltage drop detection, this invention introduces the uncontrolled rectified voltage as a reference, which can effectively distinguish the bus voltage drop caused by drive failure from other anomalies, such as abnormal input voltage drops or reading errors caused by sampling circuit failures. For example, if only the actual bus voltage on the AC side is detected to be lower than the expected bus voltage on the DC side, it may be due to an excessively low input voltage; however, if the actual bus voltage on the AC side is simultaneously detected to be close to the uncontrolled rectified voltage, the cause of the fault can be identified as drive failure.

[0028] In this embodiment, the uncontrolled rectified voltage of the rectifier circuit is used as a reference, and a comprehensive judgment is made by combining the expected bus voltage on the DC side and the actual bus voltage on the AC side. This utilizes the physical characteristic that the bus voltage will drop to the level of the uncontrolled rectified voltage when the rectifier circuit driver fails. The driver failure of the rectifier circuit can be accurately located without additional hardware circuitry, avoiding misjudgments caused by sampling errors or communication failures. This effectively protects the AC / DC power supply system and downstream loads, and reduces system cost and complexity.

[0029] Furthermore, in one possible implementation, determining whether the rectifier circuit drive is faulty includes: A drive fault is determined when a first deviation is greater than a first preset threshold and a second deviation is less than a second preset threshold. Optionally, the first preset threshold is greater than or equal to the second preset threshold.

[0030] The first deviation reflects the difference between the actual AC bus voltage and the desired DC bus voltage of the system. When the rectifier circuit is driving normally, it has boost or regulate voltage, and the actual AC bus voltage should closely track the desired DC bus voltage, resulting in a small first deviation. If the rectifier circuit fails, it loses control, and the actual AC bus voltage drops to the level of the uncontrolled rectified voltage, causing it to be significantly lower than the desired DC bus voltage, thus resulting in a large first deviation. Therefore, a first deviation greater than the threshold is a necessary condition for a drive failure.

[0031] The second deviation reflects the relationship between the desired DC-side bus voltage and the uncontrolled rectifier reference voltage. A small second deviation indicates that the desired DC-side bus voltage setting is reasonable and the input power supply voltage is within the normal range, ruling out the possibility of a bus voltage drop due to abnormal input voltage fluctuations. A large second deviation may mean that the input voltage itself is abnormally high or low, or that the desired DC-side bus voltage setting is incorrect; in this case, it should not be considered a drive fault. By introducing the second deviation as a constraint, abnormal bus voltage caused by non-drive factors can be effectively eliminated, avoiding misjudgments.

[0032] In this embodiment, a rigorous fault determination closed loop is constructed by combining the dual error logic of "large first deviation" and "small second deviation": the former confirms the phenomenon of "insufficient bus voltage output", and the latter confirms the premise of "normal input and reasonable target". The combination of the two accurately pinpoints the root cause of the fault as the failure of the rectifier circuit drive, rather than the abnormal external power supply or the error of the internal control parameters, which significantly improves the accuracy of fault determination.

[0033] In one possible implementation, the first preset threshold ranges from 20V to 40V, and the second preset threshold ranges from 20V to 40V.

[0034] Specifically, the setting of the first and second preset thresholds needs to comprehensively consider the accuracy of the sampling circuit, the system noise margin, and the sensitivity of fault identification. If the threshold is set too low, for example, a value of 5V, although it can improve the sensitivity of fault identification, the voltage ripple, sampling error, and transient fluctuations caused by load changes in the actual circuit can easily lead to the system falsely triggering fault protection under normal operating conditions, causing frequent system shutdowns and affecting the continuity of power supply. If the threshold is set too high, for example, a value of 100V, although it can effectively avoid false judgments, it will significantly reduce the sensitivity of fault identification. In the early stage of faults, such as when the drive section fails or insufficient drive capability causes a slight voltage drop, the system may not be able to identify the fault in time, causing the downstream circuits to be in an undervoltage operating state for a long time, leading to overheating and damage to the devices.

[0035] Setting the threshold range between 20V and 40V is the optimal balance point determined through extensive experimental verification. For example, when the first preset threshold is 20V, the system has high sensitivity to voltage drops, making it suitable for precision power supply scenarios with extremely high voltage stability requirements; when the threshold is 40V, the system has strong anti-interference capabilities, making it suitable for scenarios with harsh electromagnetic environments such as industrial sites; and when the threshold is the intermediate value of 30V, it balances sensitivity and anti-interference capabilities, making it suitable for most general power supply scenarios.

[0036] In this embodiment, by setting the range of the first preset threshold and the second preset threshold between 20V and 40V, the accuracy of fault identification is ensured while effectively distinguishing drive faults from other types of anomalies, such as input voltage fluctuations or sampling momentary jitter, thereby significantly improving the reliability and safety of the power supply system.

[0037] In one possible implementation, obtaining the uncontrolled rectified voltage of the rectifier circuit as a reference voltage includes: calculating the reference voltage based on the input voltage; wherein the input voltage is the mains voltage.

[0038] Input voltage refers to the voltage signal on the AC input side of a rectifier circuit. For a three-phase rectifier system, the input voltage typically refers to the three-phase phase voltage or line voltage. By detecting the input voltage and combining it with the topology parameters of the rectifier circuit, the output voltage value of the circuit in an undriven state can be theoretically calculated. This calculation method utilizes the inherent physical characteristics of the rectifier circuit, allowing the acquisition of the reference voltage to be achieved without relying on additional hardware detection circuits or complex experimental calibrations; only a conventional voltage sampling unit needs to be set up on the input side.

[0039] In this embodiment, the reference voltage is calculated based on the input voltage, which utilizes the inherent physical laws of the rectifier circuit in the uncontrolled rectification state. This allows the reference voltage to be obtained simply by detecting the input voltage, eliminating the need for additional hardware detection circuits and further reducing the hardware cost and algorithm complexity of the system.

[0040] In one possible implementation, calculating the reference voltage based on the input voltage includes determining the reference voltage as the square root of 6 times the input voltage.

[0041] This feature is primarily applicable to topologies with similar characteristics, such as three-phase Vienna rectifier circuits. For example... Figure 1 As shown, when the Vienna rectifier circuit is in an undriven state, that is, all the switching transistors in the circuit are turned off, the circuit will enter the uncontrolled rectification working mode. At this time, the circuit relies solely on the internal diode bridge arms for natural commutation, and its working principle is equivalent to that of a traditional three-phase uncontrolled rectifier bridge.

[0042] Specifically, in the uncontrolled rectification state of a three-phase Vienna rectifier circuit, the DC bus voltage is determined by the peak value of the input line voltage. According to electrical engineering principles, there is a √3 relationship between the effective value of the input phase voltage and the effective value of the line voltage, and a √2 relationship between the effective value of the line voltage and its peak value. Therefore, the peak value of the input line voltage is equal to the √6 times the effective value of the phase voltage. In the uncontrolled rectification state, the DC bus voltage will charge to near this peak value of the line voltage, meaning the reference voltage is approximately the √6 times the effective value of the input phase voltage. For example, assuming the effective value of the input phase voltage is 220V, the theoretically calculated value of the reference voltage is approximately... It should be understood that although this embodiment uses a three-phase Vienna rectifier circuit as an example to illustrate the mathematical relationship of the square root of 6, the calculation method of the reference voltage may be different for other rectifier topologies with similar uncontrolled rectification characteristics, and this invention does not specifically limit this.

[0043] In this embodiment, by determining the reference voltage as the square root of 6 times the input voltage, a definite mathematical mapping relationship between the input voltage and the reference voltage is established, providing an accurate theoretical basis for fault diagnosis. The reference voltage can be calculated in real time simply by detecting the input voltage, which greatly simplifies the detection process and reduces the hardware cost and algorithm complexity of the system.

[0044] In one possible implementation, the method further includes: in response to determining a drive fault, performing a protection action; wherein the protection action includes at least one of shutdown, alarm, or switching to a backup circuit.

[0045] Shutdown refers to the controller immediately blocking the drive pulses of all switching transistors and disconnecting contactors or relays in the main circuit of the system, cutting off the energy transmission path and preventing the fault from escalating further to the point of device burnout or safety accidents. Alarm refers to sending a fault code to the monitoring system through the communication interface, or issuing audible and visual alerts through local indicator lights or buzzers to notify maintenance personnel to carry out repairs. Switching to backup circuit refers to automatically switching the load to backup power or backup rectifier module when a fault is detected in the current rectifier circuit to ensure the continuity of system power supply, suitable for applications with extremely high reliability requirements.

[0046] The above protection actions can be combined according to the actual system configuration. For example, in the scenario of unattended charging piles, priority can be given to shutting down the system and remotely alarming; in the scenario of data center power supply, priority can be given to switching to backup circuits and alarming.

[0047] In this embodiment, by setting a clear fault response mechanism, the system safety and information feedback after a fault occurs are ensured, preventing the fault from escalating further and causing device damage or safety accidents, thus improving the practicality and safety of the entire fault detection method.

[0048] Based on the aforementioned embodiments, this method is executed during the power system startup phase.

[0049] The startup phase of a power supply system refers to the period after the system has completed power-on initialization, the main circuit contactor has not yet closed or has just begun to close, and the downstream loads have not yet been put into operation. During this phase, detection is performed, and its timing logic is typically as follows: The system controller is powered on and reset; the sampling circuit and communication module are initialized; the input voltage is detected and the reference voltage is calculated; the desired DC bus voltage and the actual AC bus voltage are obtained; and fault judgment logic is executed. If a drive fault is determined, the main circuit contactor is prevented from closing, and protection actions are directly executed; if normal is determined, the system is allowed to enter normal operation mode, the contactor is closed, and PWM modulation is initiated.

[0050] Setting the testing phase during startup offers significant technical advantages. If a drive failure is suddenly detected and a shutdown is initiated during normal system operation, it could lead to a sudden power outage, affecting production continuity and even damaging sensitive loads. However, performing testing during startup is like conducting a "physical examination," identifying potential drive failures, open circuits in drive lines, or damaged switching transistors before the system is put into operation, thus preventing the risk of the system operating with defects from the outset. At this stage, the system is not yet under load, and shutdown or maintenance will not impact the load.

[0051] In this embodiment, by locking the detection time at the power system startup stage, early interception of faults is achieved, avoiding the chain damage caused by fault operation, realizing early warning and timely loss prevention of faults, and significantly improving the safety and reliability of the power system.

[0052] The following section provides a detailed explanation of the power drive fault detection method provided in the above implementation method, using a specific charging pile application scenario as an example. This scenario employs a Vienna rectifier circuit as the front-end AC-DC converter, connected to an LLC resonant converter in the rear stage, forming a typical charging power supply architecture.

[0053] Calculation of uncontrolled rectification: Vienna uncontrolled rectification = all switching transistors (MOSFET / IGBT) are normally off, relying solely on six internal diodes to form a three-phase, three-level uncontrolled rectification, equivalent to a three-phase DCM / CCM uncontrolled rectification + neutral point clamping. The DC bus voltage is determined by the three-phase input line voltage. Figure 1 (Input current) , , S a S b S c Off, corresponding to: RMS line voltage:

[0054] Peak phase voltage:

[0055] Peak line voltage:

[0056] Typical operating conditions, effective value of phase voltage At 220V, the peak line voltage is 538.8V.

[0057] LLC Expected Bus Voltage Calculation: The desired bus voltage of LLC is determined by the output voltage, turns ratio, and gain range.

[0058] (1) Basic voltage relationship of LLC (near the resonant point, near the gain M=1): ; in, For the desired bus voltage, This refers to the output voltage of the LLC; N The transformer turns ratio is calculated as: primary turns / secondary turns. (2) Considering dead zone, voltage drop, and minimum gain margin, these are commonly used in engineering.

[0059] (3) The range that LLC must meet: In order to prevent the frequency from running too high / too low, the bus must meet the following requirements. , This is the maximum gain (typically 1.1~1.3). This is the minimum gain (typically 0.7~0.9).

[0060] Most common operating conditions: Assuming output voltage: 800V (commonly used in charging piles), turns ratio N =1.8, then the ideal busbar is: =800 / 1.8=444.4V, so the expected bus voltage is 444.4V.

[0061] The above implementation examples of drive fault detection schemes for ACDC power systems will be introduced: Specifically, the effective value of the phase voltage of the three-phase input AC power is set to 220V. According to... Figure 5 The flowchart is shown below. Based on the aforementioned reference voltage calculation logic, the controller first acquires the input voltage and calculates the theoretical output voltage of the rectifier circuit in a non-driven state (the voltage value of the uncontrolled rectifier bus), i.e., the reference voltage V1. For a three-phase Vienna rectifier circuit, the reference voltage V1 is approximately the effective value of the input phase voltage. Times. Substituting the values, we get: This value represents the theoretical limit to which the DC bus voltage will drop when the drive circuit completely fails and all switching transistors are turned off.

[0062] The system sets the desired bus voltage V2 based on the operating characteristics of the subsequent LLC resonant converter. The desired bus voltage of the LLC is determined by the output voltage, transformer turns ratio, and gain range. In this embodiment, considering the gain characteristics of the LLC resonant network and the need for overall system efficiency optimization, the desired bus voltage V2 is set to 560V. This voltage value is higher than the reference voltage V1, ensuring that the Vienna rectifier circuit operates in boost mode, enabling stable control of the DC bus voltage.

[0063] During system startup, the controller samples the DC bus voltage in real time to obtain the actual AC bus voltage V3. If a fault occurs in the drive circuit, such as an open circuit in the drive signal line or damage to the drive chip, causing the switching transistors in the Vienna rectifier circuit to be unable to receive the PWM drive signal and remain off, the rectifier circuit enters uncontrolled rectification mode, and the actual AC bus voltage V3 will quickly drop to near the reference voltage V1. The sampling circuit detects an actual AC bus voltage V3 of approximately 520V.

[0064] The controller executes the aforementioned fault diagnosis logic. The controller presets a first threshold value of 30V and a second threshold value of 30V. The diagnosis logic unit compares the calculated deviation value with the threshold value.

[0065] First, calculate the first deviation ERROR1 between the desired DC bus voltage V2 and the actual AC bus voltage V3. Substituting the values: ERROR1 = V2 - V3 = 560V - 520V = 40V. This deviation is greater than the first preset threshold of 30V, indicating that the actual AC bus voltage is significantly lower than the desired DC bus voltage, and the system has an abnormality of insufficient output.

[0066] Next, calculate the second deviation ERROR2 between the desired DC bus voltage V2 and the reference voltage V1. Substituting the values: ERROR2 = V2 - V1 = 560V =21.2V. This deviation value reflects the distance between the system control target and the theoretical no-drive limit state.

[0067] At this point, the first deviation ERROR1 is greater than the first preset threshold, satisfying the "insufficient output" criterion; simultaneously, the second deviation ERROR2 is less than the second preset threshold, satisfying the "normal input and reasonable target" criterion. This is because the smaller second deviation ERROR2 indicates that the difference between the expected DC bus voltage V2 and the reference voltage V1 is within a reasonable range, eliminating the possibility of an abnormal increase in input voltage causing V1 to increase and thus causing V3 to drop, and also eliminating interference from communication errors causing V2 to be set too low. The system comprehensively determines that both conditions are met simultaneously, thus accurately identifying the root cause of the fault as a drive module failure, rather than other external factors.

[0068] In contrast, if the system is in normal operating condition, the Vienna rectifier circuit will boost the voltage normally under the control of the drive signal, and the actual bus voltage V3 on the AC side will stabilize near the expected bus voltage V2 (560V) on the DC side. At this time, the first deviation ERROR1 = 560V - 560V = 0V, which is less than the first preset threshold. The system is then determined to be fault-free and operating normally.

[0069] If the system experiences an abnormal input voltage drop, such as the input phase voltage dropping to 180V, the calculated value of the reference voltage V1 will be updated to... The actual bus voltage V3 on the AC side will also drop to around 441V. At this time, the first deviation ERROR1 = 560V - 441V = 119V, which is significantly greater than the first preset threshold. However, the second deviation ERROR2 = 560V - 441V = 119V, which is significantly greater than the second preset threshold. This indicates that the drop in the actual bus voltage on the AC side is due to a decrease in the reference voltage V1 caused by an excessively low input voltage, rather than a drive fault. Based on the characteristic that "ERROR2 is greater than the second preset threshold", the system effectively eliminates the misjudgment of a drive fault and avoids unnecessary shutdown protection.

[0070] In this embodiment, through practical application in the Vienna+LLC charging pile system, the detection method provided by this invention was verified to accurately distinguish between various operating conditions such as drive failure, normal operation, and abnormal input voltage. This method utilizes the inherent physical characteristics of the circuit to construct a benchmark, requiring only software algorithms to achieve fault diagnosis without the need for additional hardware detection circuits, significantly reducing system costs and improving the accuracy of fault identification and system reliability.

[0071] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0072] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0073] Figure 6 A schematic diagram of the drive fault detection device for an ACDC power system provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below: like Figure 6 As shown, the drive fault detection device 6 of the ACDC power system includes: a reference voltage acquisition module 601, a desired bus voltage acquisition module 602, an actual bus voltage acquisition module 603, and a fault judgment module 604.

[0074] The reference voltage acquisition module 601 is configured to acquire the uncontrolled rectified voltage of the rectifier circuit as a reference voltage.

[0075] The desired bus voltage acquisition module 602 is configured to acquire the desired bus voltage on the DC side.

[0076] The actual bus voltage acquisition module 603 is configured to acquire the actual bus voltage on the AC side.

[0077] The fault judgment module 604 is configured to determine whether the rectifier circuit drive is faulty based on the first deviation between the expected DC bus voltage and the actual AC bus voltage, and the second deviation between the expected DC bus voltage and the reference voltage.

[0078] The fault diagnosis module 604 is the core logic processing unit of the entire device. At the hardware level, the fault diagnosis module 604 can be implemented by the processing unit and logic control unit within the processor. The processor reads three parameters: the reference voltage, the desired DC bus voltage, and the actual AC bus voltage, and performs deviation calculations and threshold comparisons according to preset program logic. When the diagnosis result meets the preset fault conditions, the fault diagnosis module outputs a fault flag signal. This fault flag signal can trigger an external alarm device, be uploaded to the monitoring system via a communication interface, or directly drive the protection circuit to operate.

[0079] In this embodiment, a functional architecture comprising a reference voltage acquisition module, a desired bus voltage acquisition module, an actual bus voltage acquisition module, and a fault judgment module is constructed, providing a concrete physical implementation for the aforementioned drive fault detection method for ACDC power systems. This device fully utilizes existing voltage sampling circuits and processor resources, eliminating the need for additional drive signal detection hardware. While ensuring fault detection accuracy, it significantly reduces system hardware costs and structural complexity, thereby improving the integration and reliability of the ACDC power system.

[0080] Furthermore, the reference voltage acquisition module 601 includes a calculation unit configured to calculate the reference voltage based on the input voltage; wherein the input voltage is the mains voltage.

[0081] In this embodiment, a dedicated computing unit is set up in the reference voltage acquisition module to achieve localized and rapid calculation of the reference voltage. Compared with the method of obtaining the reference value through external communication, this embodiment does not rely on complex communication links. It can complete the reference construction using only local sampling data and the processor's internal computing resources, which significantly reduces the system's occupation of communication resources, improves the response speed and real-time performance of fault detection, and also enhances the system's independent survivability in the event of communication failure.

[0082] Figure 7 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Figure 7 As shown, the electronic device 7 of this embodiment includes a processor 70 and a memory 71. The memory 71 stores a computer program 72. When the processor 70 executes the computer program 72, it implements the steps in the various method embodiments described above. Alternatively, when the processor 70 executes the computer program 72, it implements the functions of each module / unit in the various device embodiments described above.

[0083] For example, computer program 72 may be divided into one or more modules / units, which are stored in memory 71 and executed by processor 70 to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of computer program 72 in electronic device 7.

[0084] Electronic device 7 may include, but is not limited to, processor 70 and memory 71. Those skilled in the art will understand that... Figure 7 This is merely an example of electronic device 7 and does not constitute a limitation on electronic device 7. It may include more or fewer components than shown, or combine certain components, or different components. For example, electronic device 7 may also include input / output devices, network access devices, buses, etc.

[0085] For the sake of simplicity and clarity, only the above-described functional modules / units are used as examples. In practical applications, the functions described above can be assigned to different functional modules / units as needed. These modules / units can be implemented in hardware, software, or a combination of both.

[0086] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0087] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for detecting drive faults in an AC / DC power supply system, characterized in that, include: Obtain the uncontrolled rectified voltage of the rectifier circuit as a reference voltage; Obtain the desired DC-side bus voltage and the actual AC-side bus voltage; Based on the first deviation between the expected DC bus voltage and the actual AC bus voltage, and the second deviation between the expected DC bus voltage and the reference voltage, it is determined whether the rectifier circuit drive is faulty.

2. The method for detecting drive faults in an ACDC power supply system according to claim 1, characterized in that, The step of determining whether the rectifier circuit drive is faulty includes: In response to the first deviation being greater than a first preset threshold and the second deviation being less than a second preset threshold, a drive fault is determined.

3. The method for detecting drive faults in an ACDC power supply system according to claim 2, characterized in that, The first preset threshold value ranges from 20V to 40V, and the second preset threshold value ranges from 20V to 40V.

4. The method for detecting drive faults in an ACDC power system according to claim 1, characterized in that, The step of obtaining the uncontrolled rectified voltage of the rectifier circuit as a reference voltage includes: The reference voltage is calculated based on the input voltage; wherein, the input voltage is the mains voltage.

5. The method for detecting drive faults in an ACDC power system according to claim 4, characterized in that, The calculation of the reference voltage based on the input voltage includes: The reference voltage is determined to be the square root of 6 times the input voltage.

6. The method for detecting drive faults in an ACDC power supply system according to claim 1, characterized in that, Also includes: In response to determining a drive fault, a protection action is executed; wherein the protection action includes at least one of shutdown, alarm, or switching to a backup circuit.

7. The method for detecting drive faults in an ACDC power supply system according to claim 1, characterized in that, The method is performed during the power system startup phase.

8. A drive fault detection device for an AC / DC power supply system, characterized in that, include: The reference voltage acquisition module is configured to acquire the uncontrolled rectified voltage of the rectifier circuit as a reference voltage; The desired bus voltage acquisition module is configured to acquire the desired bus voltage on the DC side. The actual bus voltage acquisition module is configured to acquire the actual bus voltage on the AC side. The fault diagnosis module is configured to determine whether the drive of the rectifier circuit is faulty based on a first deviation between the expected DC bus voltage and the actual AC bus voltage, and a second deviation between the expected DC bus voltage and the reference voltage.

9. The drive fault detection device for an ACDC power system according to claim 8, characterized in that, The reference voltage acquisition module includes a calculation unit configured to calculate the reference voltage based on the input voltage; wherein the input voltage is the mains voltage.

10. An electronic device, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method as described in any one of claims 1 to 7.

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