Power conversion apparatus and detection method

Abstract

The embodiments of the present application are applied to the technical field of power supply processing. Provided are a power conversion apparatus and a detection method. The power conversion apparatus comprises a control circuit and a direct-current / direct-current conversion circuit. The direct-current / direct-current conversion circuit comprises an inductor and a switching transistor. The switching transistor is used for being connected in parallel to a direct-current power source, and the inductor is connected in series in a loop formed by the direct-current power source and the switching transistor. The control circuit is used for: in a starting process of the power conversion apparatus, controlling the switching transistor to remain in an on state within a target duration or controlling the switching transistor to turn on and turn off in a target number of switching periods; and after the target duration, when a current value of the inductor is greater than a preset current threshold, determining that there is a short circuit between adjacent winding coils of the inductor, and executing an abnormality handling operation for the inductor. By controlling a waveform generation duration in a starting stage of the power conversion apparatus, the embodiments of the present application realize abnormal power-on detection of the inductor on a direct-current side of the power conversion apparatus on the basis of ensuring the operation safety.

Description

A power conversion device and detection method

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on January 31, 2024, with application number 202410153068.7 and application name “A Power Conversion Device and Detection Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of power supply processing technology, and in particular to a power conversion device and a detection method. Background Art

[0003] In the field of power supply processing (such as photovoltaic power supply), power conversion processing can be performed on power supply signals based on power conversion devices. During the transmission and processing of power supply signals, both direct current and alternating current are involved. Depending on the application scenario, when power conversion is performed on the power supply signal, conversion processing may be performed between direct current and alternating current (i.e., direct current / alternating current conversion) and / or between direct current and direct current (i.e., direct current / direct current conversion).

[0004] Existing power conversion circuits often include inductors. The operational safety of inductors is crucial to the safety and reliability of the power supply system. Typically, devices for detecting the operational safety of inductors are installed on the AC side of power conversion circuits (e.g., DC / AC conversion circuits). However, devices for detecting the safety of inductors are often lacking on the DC side of power conversion circuits (e.g., DC / DC conversion circuits). In particular, there is a lack of inductor safety detection for the DC / DC conversion circuits of power conversion devices during startup. Summary of the Invention

[0005] The embodiments of the present application provide a power conversion device and a detection method, which achieve accurate detection of the inductor safety on the current side.

[0006] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect, a power conversion device is provided, comprising a control circuit and a DC / DC conversion circuit. The DC / DC conversion circuit comprises an inductor and a switching tube. The switching tube is connected in parallel with a DC power supply, and the inductor is connected in series in a loop formed by the DC power supply and the switching tube. The control circuit is configured to: during startup of the power conversion device, control the switching tube to remain on for a target duration or to turn the switching tube on and off within a target number of switching cycles. If the current flowing through the inductor exceeds a preset current threshold after the target duration or the target number of switching cycles, an inductor abnormality handling operation is performed.

[0008] Exemplarily, the startup of a power conversion device means that the power conversion device is connected to the working power supply of the equipment to achieve power-on. After the power conversion device is powered on, the control circuit therein will also be powered on. After the control circuit is powered on, there will be a self-test process, which can detect various working status information of the power conversion device to ensure the working stability and safety of the power conversion device. For example, the state of the inductance of the DC / DC conversion circuit in the power conversion device can be detected. Only in this way can the subsequent slow start of the DC / DC conversion circuit and the operation of the DC / AC conversion circuit be carried out. The startup process of the power conversion device involved in this application is the process in which the power conversion device performs a self-test after power-on. It can be understood that in some possible scenarios, inductance detection can also be performed during the operation of the DC / AC conversion circuit.

[0009] Exemplarily, based on the target duration of continuous conduction, the switch tube can be kept in a continuous conduction state within the target duration. Exemplarily, when the conduction of the switch tube is controlled based on the switching cycle, the duty cycle of the switch tube within one switching cycle is determined, that is, there will be an on state and an off state of a certain proportion. When the conduction of the switch tube is controlled based on a plurality of switching cycles, the switch tube exhibits an intermittent conduction state within a plurality of cycles. In the method of controlling the conduction of the switch tube in a switching cycle manner, the voltage transformation size of the DC / DC conversion circuit can be controlled based on the adjustment of the duty cycle (i.e., the ratio between the on state and the off state) within each switching cycle. In actual applications, the conduction control method can be adaptively designed according to the requirements of the application scenario.

[0010] Regarding inductors, there is an inductance characteristic formula that describes the relationship between the inductor's value and the current flowing through it. In a power converter's DC / DC converter circuit, operation begins when DC power is input. The DC / DC converter circuit contains an inductor and a switching transistor. The switching transistor and inductor implement DC-DC power conversion. During the DC / DC converter circuit's startup phase, if the insulation layer on the outer surface of the inductor's winding coil breaks, it can cause a short circuit between adjacent windings, resulting in an inter-turn short circuit in the inductor. Therefore, it is necessary to perform inductor safety testing during the startup phase of the DC / DC converter circuit of the power converter. Existing inductance detection solutions directly calculate the inductor's actual value based on the inductance characteristic formula to determine whether the inductor is abnormal. However, this method is not suitable for detecting inductance anomalies in a DC / DC converter circuit. This is because testing the inductance in the DC / DC converter circuit of a power converter requires that the DC / DC converter circuit be in normal operation. When a DC / DC converter circuit receives DC power from a DC power source, a large inductor current flows through the inductor of the DC / DC converter circuit. While the inductor's characteristic formula can be used to detect the inductor's state, the current flowing through the inductor is very large. If the inductor is abnormal, the current flowing through it will be even greater than that of a normal inductor. Because this detection method requires the abnormal inductor to operate unchecked, the current flowing through it can be sufficient to damage the power converter. Therefore, this detection method, which directly detects the actual inductor value based on the inductor characteristic formula, cannot avoid the safety issues caused by abnormal inductance. Furthermore, this detection method cannot be applied during the startup phase of the power converter. Currently, there is no solution for safety testing the inductor of a DC / DC converter circuit during startup. However, in the embodiments of the present application, during the startup phase of the power converter, the control circuit only controls the switch to conduct for a target duration. Under a specific conduction duration and input voltage, inductors with different inductance values ​​will have different current values. The inductance value of each normal operation is the rated inductance value of the inductor product known at the factory. When the winding of the inductor is short-circuited, the inductance value of the short-circuited inductor will be attenuated. Therefore, in actual applications, by reasonably designing the target duration or target number of switching cycles, the target duration or target number of switching cycles is satisfied so that the current value of the short-circuited inductor will not damage the power conversion device. In this embodiment, under the same conduction duration and the same input voltage, the inductance value of the inductor is inversely proportional to the current value flowing through the inductor. Therefore, the current value flowing through the short-circuited inductor will be greater than the current value flowing through the normal inductor.In actual applications, the current value flowing through the inductor obtained based on the target duration or target number of switching cycles is judged. If the current value flowing through the measured inductor is greater than a certain preset current threshold, it indicates that the winding coils of the inductor are short-circuited. At this time, relevant inductor abnormality handling operations can be performed.

[0011] In one possible embodiment, the control circuit includes a sampling circuit, an overcurrent protection circuit, and a control chip. The sampling circuit is connected to the output terminal of the inductor and the overcurrent protection circuit, respectively. The overcurrent protection circuit is also connected to the control chip. The sampling circuit is configured to obtain the current value flowing through the inductor and transmit it to the overcurrent protection circuit. The overcurrent protection circuit is configured to output an abnormality indication signal to the control chip when the current value flowing through the inductor exceeds a preset current threshold. The control chip is configured to perform an inductor abnormality handling operation based on the abnormality indication signal. In an embodiment of the present application, an overcurrent protection circuit is provided in the control circuit of the power conversion device. In this case, the overcurrent protection circuit determines an abnormality of the inductor based on the relationship between the current value flowing through the inductor obtained by sampling and the preset current threshold. When adjacent windings of the inductor are short-circuited, the overcurrent protection circuit can send a corresponding abnormality indication signal to the control chip. The control chip performs a corresponding inductor abnormality handling operation based on the abnormality indication signal.

[0012] In one possible implementation, the control circuit includes a sampling circuit and a control chip. The sampling circuit is connected to the output end of the inductor and the control chip, respectively. Wherein: the sampling circuit is used to: obtain the current value flowing through the inductor and transmit it to the overcurrent protection circuit. The control chip is used to: perform an inductor abnormality processing operation when the current value flowing through the inductor is greater than a preset current threshold. In an embodiment of the present application, the sampling circuit can sample and obtain the current at the output end of the inductor. The control chip determines whether the inductor is abnormal based on the relationship between the current value flowing through the inductor and the preset current threshold. When the control chip confirms that the current value flowing through the inductor is greater than the preset current threshold, the corresponding inductor abnormality processing operation can be performed.

[0013] In one possible implementation, the preset current threshold is greater than a rated peak current value, where the rated peak current value is determined by the inductor's input voltage, the inductor's rated inductance, and a target duration; or, alternatively, the rated peak current value is determined by the inductor's input voltage, the inductor's rated inductance, and the target number of switching cycles. The rated inductance value is the inductance value of the inductor during normal operation.

[0014] In some examples, the preset current threshold is also less than an abnormal peak current value, and the abnormal peak current value is determined by the input voltage of the inductor, the post-attenuation inductance of the inductor, and a target duration, or the abnormal peak current value is determined by the input voltage of the inductor, the post-attenuation inductance of the inductor, and the target number of switching cycles. The post-attenuation inductance is the inductance value of the inductor when adjacent windings are short-circuited.

[0015] In the embodiment of the present application, the rated inductance is the inductance value when the inductor is operating normally. The inductance value after attenuation is the inductance value when the adjacent winding coils are short-circuited. In the embodiment of the present application, the specific values ​​of the rated peak current value and the abnormal peak current value are determined by the inductance values ​​corresponding to the normal inductance and the abnormal inductance. Each inductor has its rated inductance value, that is, the normal inductance value L1 during normal operation. When the input voltage Upv of the inductor in the DC / DC conversion circuit is determined, the inductor in normal operation has a corresponding rated peak current value i1. According to the inductance characteristic formula L*di / dt=U (where i is the current, t is the duration, di is the change in current, dt is the change in time, U is the input voltage, and L is the actual inductance value), it can be seen that when the inductor is operating normally, the inductance value of the inductor is the normal inductance value L1, and the duration of the charging current is fixed at t1. At this time, the calculation formula for the corresponding rated peak current value i1 is: i1=Upv*t1 / L1. When the inductor is short-circuited, the inductance value of the inductor will decay, and the inductance value of the inductor at this time is the decayed inductance value L2. Because the duration of the charging current is fixed at t1, at this time, the calculation formula of the corresponding abnormal peak current value i2 is: i2 = Upv*t1 / L2. In summary, it can be seen that when the inductor is in normal working state and short-circuit state, its actual inductance value is different, that is, the inductance value of the inductor is inversely proportional to the current value flowing through the inductor. When the current duration is fixed, the corresponding output current values ​​of the two are also different. The value of the preset current threshold can be set between the rated peak current value and the abnormal peak current value, and the distinction between normal inductance and abnormal inductance can be achieved based on the preset current threshold.

[0016] In a possible implementation manner, the first absolute value is equal to the second absolute value. The first absolute value is the absolute value of the difference between a preset current threshold and a rated peak current value, and the second absolute value is the absolute value of the difference between the preset current threshold and an abnormal peak current value. In the embodiments of the present application, when the inductor is short-circuited, the inductance value of the inductor will decay. At this time, the inductance value of the inductor is the decayed inductance value L2, and the duration of the charging current is fixed as t1. At this time, the calculation formula for the corresponding abnormal peak current value i2 is: i2 = Upv * t1 / L2. At this time, based on the target duration or the number of switching cycles of the target, the value of the preset current threshold a can be between the rated peak current value i1 and the abnormal peak current value i2. Since i1 < a < i2, the equation of the first absolute value and the second absolute value can also be expressed as: (i2 - a) = (a - i1). In the embodiments of the present application, the difference between the preset current threshold a and the rated peak current value i1 and the abnormal peak current value i2 is equal. At this time, the detection result can have high reliability.

[0017] In a possible implementation manner, the control circuit is further configured to: when the current value flowing through the inductor is less than or equal to the preset current threshold, keep the power conversion device powered on. In the embodiments of the present application, when, in the startup stage of the power conversion device, it is detected that the current value flowing through the inductor is less than or equal to the preset current threshold, it is proved that the inductor on the DC side of the power conversion device is in a normal state. At this time, in the case that there are no other faults in the power conversion device, the startup operation of the power conversion device can be kept, so that the power conversion device can be normally put into use.

[0018] In a possible implementation manner, the control circuit is further configured to: when the DC / DC conversion circuit of the power conversion device is in a working state, obtain the working current value of the current flowing through the inductor in the working state. Determine the actual inductance value of the inductor according to the working current value of the current flowing through the inductor. When the actual inductance value of the inductor is less than the preset inductance threshold, perform an inductor abnormality handling operation. In the embodiments of the present application, after the power conversion device is powered on, when the DC / DC conversion circuit is in a working state, the actual inductance value of the inductor can be calculated according to the actually detected working current value, and it can be determined whether the inductor on the DC side of the power conversion device is working normally according to the actual inductance value of the inductor. Based on the inductor detection in the working stage of the DC / DC conversion circuit and combined with the inductor detection in the process of starting up the power conversion device as described above, the inductor detection of the DC side of the power conversion device can be realized systematically and comprehensively.

[0019] In one example, determining the actual inductance of the inductor based on the operating current value of the current flowing through the inductor includes: when the operating current flowing through the inductor is a continuous inductor current, calculating the actual inductance of the inductor according to a continuous inductor current algorithm based on the obtained operating current value. When the current flowing through the inductor is a discontinuous inductor current, calculating the actual inductance of the inductor according to a discontinuous inductor current algorithm based on the obtained operating current value. In this embodiment of the present application, it is possible to match the corresponding calculation method to different operating conditions of the inductor current signal, thereby achieving comprehensive abnormal calculation of the inductor under different operating conditions when the inductor is in an operating state.

[0020] In one possible implementation, the inductor abnormality handling operation includes controlling the power conversion device to shut down, outputting an inductor abnormality alarm information, or reducing the input power of the inductor. In the embodiments of the present application, different inductor abnormality handling operations can be adaptively designed according to different scenarios, such as controlling the power conversion device to shut down, outputting an inductor abnormality alarm information, or reducing the input power of the inductor.

[0021] In some possible implementations, the DC / DC converter circuit further includes an input capacitor, an output capacitor, and a diode. The diode is connected in series to the output end of the inductor, and the switch tube is connected between the inductor and the diode. The input capacitor and the output capacitor are respectively connected in parallel with the switch tube, and the input capacitor is connected to the input end side of the inductor, and the output capacitor is connected to the output end side of the diode. In an embodiment of the present application, the input capacitor and the output capacitor can respectively implement filtering processing at the input end and the output end of the DC / DC converter circuit. The diode can ensure the unidirectional conductivity of the current transmission at the output end of the inductor. After setting the input capacitor, the voltage at the input capacitor is the input voltage corresponding to the inductor in the DC / DC converter circuit.

[0022] In some possible embodiments, the power conversion device further includes a DC / AC conversion circuit, wherein the input of the DC / AC conversion circuit is connected to the output of the DC / DC conversion circuit. In embodiments of the present application, a DC / AC conversion circuit may also be provided in the power conversion device. The DC / AC conversion circuit may receive DC power from the DC / DC conversion circuit and convert the DC power to generate AC power. This AC power may be transmitted to an AC power receiving device (e.g., a power grid and / or a load device).

[0023] In a second aspect, an embodiment of the present application further provides a detection method, which is applied to a power conversion device. The power conversion device includes a DC / DC conversion circuit. The DC / DC conversion circuit includes an inductor and a switching tube. The switching tube is used to be connected in parallel with a DC power supply, and the inductor is connected in series in a loop formed by the DC power supply and the switching tube. The method includes: during the startup process of the power conversion device, controlling the switching tube to be continuously turned on within a target duration or controlling the switching tube to be turned on and off within a target number of switching cycles. After the target duration or the target number of switching cycles, when the current value flowing through the inductor is greater than a preset current threshold, an inductor abnormality processing operation is performed.

[0024] In one possible implementation, when the current value flowing through the inductor is greater than a preset current threshold, performing the inductor abnormality processing operation includes: when the current value flowing through the inductor is greater than the preset current threshold, obtaining an abnormality indication signal; and performing the inductor abnormality processing operation based on the abnormality indication signal.

[0025] In one possible implementation, the preset current threshold is greater than a rated peak current value, and the rated peak current value is determined by the input voltage of the inductor, the rated inductance of the inductor, and a target duration, or the rated peak current value is determined by the input voltage of the inductor, the rated inductance of the inductor, and the target number of switching cycles. The rated inductance value is the inductance value of the inductor during normal operation.

[0026] In some examples, the preset current threshold is also less than an abnormal peak current value, and the abnormal peak current value is determined by the input voltage of the inductor, the post-attenuation inductance of the inductor, and a target duration, or the abnormal peak current value is determined by the input voltage of the inductor, the post-attenuation inductance of the inductor, and the target number of switching cycles. The post-attenuation inductance is the inductance value of the inductor when adjacent windings are short-circuited.

[0027] In one possible implementation, the first absolute value is equal to the second absolute value, the first absolute value is the absolute value of the difference between the preset current threshold and the rated peak current value, and the second absolute value is the absolute value of the difference between the preset current threshold and the abnormal peak current value.

[0028] In a possible implementation, the method further includes: when the current value flowing through the inductor is less than or equal to a preset current threshold, keeping the power conversion device turned on.

[0029] In one possible embodiment, the method further includes: determining an actual inductance value of the inductor based on an operating current value of a current flowing through the inductor when the DC / DC converter circuit of the power converter device is in an operating state; and performing an inductor abnormality handling operation when the actual inductance value of the inductor is less than a preset inductance value threshold.

[0030] In one possible implementation, determining the actual inductance of the inductor based on the operating current value of the current flowing through the inductor includes: when the current flowing through the inductor is a continuous inductor current, determining the actual inductance of the inductor based on the operating current value at the output terminal of the inductor according to a continuous inductor current algorithm. When the current flowing through the inductor is a discontinuous inductor current, determining the actual inductance of the inductor based on the operating current value at the output terminal of the inductor according to a discontinuous inductor current algorithm.

[0031] In a possible implementation, the inductor abnormality processing operation includes controlling the power conversion device to shut down, outputting inductor abnormality alarm information, or reducing the input power of the inductor.

[0032] Regarding the technical principles and beneficial effects of the above-mentioned second aspect, please refer to the relevant description of the above-mentioned first aspect, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic structural diagram of a power supply system provided in an embodiment of the present application;

[0034] FIG2 is a schematic structural diagram of a first power conversion device in the prior art;

[0035] FIG3 is a schematic structural diagram of another first power conversion device in the prior art;

[0036] FIG4 is a schematic structural diagram of a second power conversion device provided in an embodiment of the present application;

[0037] FIG5 is a first schematic diagram showing changes in inductor current over time of a normal inductor and a short-circuit inductor provided by an embodiment of the present application;

[0038] FIG6 is a second schematic diagram showing changes in inductor current over time for another normal inductor and a short-circuit inductor provided by an embodiment of the present application;

[0039] FIG7 is a second structural diagram of another second power conversion device provided in an embodiment of the present application;

[0040] FIG8 is a third structural diagram of another second power conversion device provided in an embodiment of the present application;

[0041] FIG9 is a fourth structural diagram of another second power conversion device provided in an embodiment of the present application;

[0042] FIG10 is a schematic diagram of a flow chart of a detection method provided in an embodiment of the present application;

[0043] FIG11 is a third schematic diagram showing changes in inductor current over time for another normal inductor and a short-circuit inductor provided in an embodiment of the present application;

[0044] FIG12 is a first schematic diagram of a change in inductive charging based on a driving signal with a continuous effective pulse width according to an embodiment of the present application;

[0045] FIG13 is a second schematic diagram of a change in inductive charging based on a drive signal with an intermittent effective pulse width according to an embodiment of the present application;

[0046] FIG14 is a schematic diagram of a flow chart of another detection method provided in an embodiment of the present application;

[0047] FIG15 is a schematic diagram of a processing flow of a second control circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] It should be noted that the terms "first", "second", etc. involved in the embodiments of the present application are only used to distinguish features of the same type and cannot be understood as indicating relative importance, quantity, order, etc.

[0049] The terms "exemplary" or "for example" in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0050] The terms "coupling" and "connection" involved in the embodiments of this application should be understood in a broad sense. For example, they may refer to a physical direct connection, or an indirect connection achieved through electronic devices, such as a connection achieved through resistors, inductors, capacitors or other electronic devices.

[0051] An embodiment of the present application provides a power supply system. As shown in FIG1 , the power supply system 1000 includes a DC power supply 200 and a power conversion device 100. The input terminal of the power conversion device 100 is connected to the output terminal of the DC power supply 200 to obtain DC power from the DC power supply 200. For example, taking the power supply system 1000 as a photovoltaic power supply system, the DC power supply 200 can be a photovoltaic array. For example, taking the power supply system 1000 as a power supply system in a scenario where the power supply is an uninterruptible power supply, the DC power supply 200 can be an energy storage device built into or external to the power conversion device 100.

[0052] When the power conversion device 100 shown in FIG1 is a first power conversion device provided in the prior art that does not include an inductance detection function, as shown in FIG2 , the first power conversion device 100A includes a direct current / direct current (DC / DC) conversion circuit 10. The DC / DC conversion circuit 10 includes an inductor L and a switch tube S. The switch tube S is connected to the output end of the inductor LL. For example, the input end of the inductor L is connected to the positive input terminal IN+ of the DC / DC conversion circuit 10, the output end of the inductor L is respectively connected to the first end of the switch tube S and the positive output terminal OUT+ of the DC / DC conversion circuit 10, and the second end of the switch tube S is respectively connected to the negative input terminal IN- and the negative output terminal OUT- of the DC / DC conversion circuit 10. When the input voltage of the inductor L is constant, by controlling the conduction duration and / or conduction frequency of the switch tube S, the voltage of the current output by the inductor can be controlled, thereby achieving the purpose of DC voltage conversion (e.g., boost processing).

[0053] In the prior art shown in FIG2 , the pins of the inductor L are soldered to the printed circuit board (PCB) on which the first power conversion device 100A is located. When the inductor L winding is affected by external forces, such as collisions, causing the outer insulation layer of the inductor L to rupture, a short circuit occurs between adjacent windings of the inductor L, causing an inter-turn short circuit in the inductor L. After the inter-turn short circuit occurs, the current flowing into the short-circuited winding of the inductor L will soar to dozens of times the normal current. After the heat conduction effect, the temperature at the pins of the inductor L rises sharply, causing problems such as carbonization of the PCB, burning of the first power conversion device 100A, and smoking. Typically, there is a lack of relevant devices on the current side to detect the safety of the inductor.

[0054] In some possible implementations, as shown in FIG3 , a first control circuit 20A can be provided in a first power conversion device 100A of the prior art. The first control circuit 20A includes a first sampling circuit 21A and a controller 22A. The first sampling circuit 21A is connected to the output end of the inductor L. The first sampling circuit 21A is configured to obtain the current output by the inductor L when the first power conversion device 100A is in operation. The controller 22A is configured to calculate the actual inductance of the inductor L based on the current value flowing through the inductor L and a calculation algorithm under a continuous inductor current operating condition, and determine whether the operation of the inductor L is abnormal based on the calculated actual inductance value. However, this method can only detect and calculate the inductance L of the DC / DC conversion circuit 10 when the power supply system is operating normally, and this calculation is for detection and calculation under a continuous inductor current operating condition and is not suitable for calculation under a discontinuous inductor current operating condition. Additionally, existing power factor correction (PFC) circuits include devices for detecting abnormalities in the PFC circuit's inductor. However, these devices only calculate the inductance value based on a typical inductor characteristic formula and cannot be directly applied to the power supply system 1000. This is because detecting the inductor L based on its inductance characteristics requires that the inductor L be operating normally. This is because when detecting the inductance in the DC / DC converter circuit 10 of the power variation device 100, the DC / DC converter circuit 10 must be operating normally. When the DC / DC converter circuit 10 receives DC power from the DC power source 200, a large inductor current flows through the inductor L of the DC / DC converter circuit 100. While the inductor characteristic formula can detect the condition of the inductor L, the current flowing through the inductor L is very large. If the inductor L is abnormal, the current flowing through it will be even greater than that of a normal inductor L. Because this detection method requires allowing abnormal inductor L to operate, the inductor current flowing through inductor L when the inductor L is operating abnormally is sufficient to damage the power conversion device 100. Therefore, this detection method that directly detects the actual inductance value of inductor L based on the inductor characteristic formula cannot avoid the safety issues caused by abnormal inductor L. Moreover, this detection method cannot be applied to the startup phase of the power conversion device 100. During the startup phase of the power conversion device 100, if the DC / DC converter circuit 10 is not controlled to start operation, no current will flow through the inductor L of the DC / DC converter circuit 10. If the DC / DC converter circuit 10 is controlled to start operation, then in the event of an abnormal inductor L, an abnormal current will have already been generated in the power conversion device 100, posing a safety hazard. At this point, it may be too late to calculate the inductance value of inductor L based on the typical inductor characteristic formula.

[0055] In order to implement safety detection of the inductor L on the DC side of the power conversion device 100 during the startup process of the power conversion device 100, an embodiment of the present application provides a second power conversion device, which implements inductor detection during the startup phase based on power-on wave detection. As shown in Figure 4, the second power conversion device 100B includes a second control circuit 20B and a DC / DC conversion circuit 10; the DC / DC conversion circuit 10 includes an inductor L and a switch tube S; the switch tube S is used to be connected in parallel with the DC power supply, and the inductor L is connected in series in the loop formed by the DC power supply and the switch tube S. Among them, the second control circuit 20B is used to: during the startup process of the second power conversion device 100B, control the switch tube S to be continuously turned on for a target duration or to control the switch tube to be turned on and off within a target number of switching cycles. After the target duration or the target number of switching cycles, when the current value flowing through the inductor L is greater than a preset current threshold, the inductor L abnormality handling operation is performed.

[0056] In some possible implementations, the second control circuit 20B can output a drive signal to the switch S, and control the conduction of the switch S based on the drive signal. Different forms of drive signals can be used to control the conduction of the switch S. In one example, the drive signal can be a high-level signal with a continuous effective pulse width. In this case, the DC / DC converter circuit 10 performs voltage conversion processing on the input DC power, and the voltage conversion magnitude is a fixed value. The duration of the effective pulse width of the drive signal is the target duration. In one example, the drive signal can be a level signal with a certain duty cycle. The duty cycle refers to the ratio between the effective pulse width duration and the low-level (or zero-level) duration in the drive signal within a switching cycle, which reflects the ratio of the duration of the controlled switch in the on state to the duration of the controlled switch in the off state within a switching cycle. By controlling the conduction of the switch based on the switching cycle, the voltage conversion capability of the DC / DC converter circuit 10 can be adjusted by adjusting the duty cycle of the drive signal within the switching cycle. Regardless of whether the switch tube S is controlled to be turned on by a target duration or a target number of switching cycles, the duration of the charging current of the inductor L is controlled by controlling the actual effective conduction time of the switch tube S.

[0057] In the embodiment of the present application as shown in FIG4 , each inductor L has its rated inductance value, namely, the normal inductance value L1 during normal operation. When the input voltage of the DC / DC converter circuit 10 is determined, such as the voltage Upv provided by the DC power supply 200, the normally operating inductor L has a corresponding rated peak current value i1. According to the inductance characteristic formula L*di / dt=U (where i is the current, t is the duration of the effective charging time, di is the change in current, dt is the change in time, U is the input voltage, and L is the actual inductance value), as shown in FIG5 , taking the control of the switch tube S based on the target duration as an example, the target duration is the effective charging time of the inductor L. When the inductor L is operating normally, the inductance value of the inductor L is the normal inductance value L1, and the duration of the charging current of the inductor L is fixed at t1. At this time, the corresponding rated peak current value i1 is calculated as follows: i1=Upv*t1 / L1. When inductor L is short-circuited due to a shorted winding, the inductor L's inductance decays. At this point, the inductor L's inductance is the decayed value L2. The duration of the charging current is fixed at t1. At this point, the corresponding abnormal peak current value i2 is calculated as: i2 = Upv * t1 / L2. In summary, it can be seen that the actual inductance of inductor L is different when it is in normal operation and in a short-circuit state. When the current duration is fixed, the corresponding output current values ​​are also different. Therefore, during the startup phase of the second power conversion device 100B, the second control circuit 20B only needs to control the switch S to conduct for a target duration or a target number of switching cycles to enable the inductor L to output current. This target duration or number of switching cycles satisfies the requirement for different current outputs under different operating conditions of the inductor L. At the same time, the output current when the inductor L is short-circuited will not be excessive, causing safety issues. In response to the second power conversion device 100B being powered on, the second control circuit 20B can obtain the current value flowing through the inductor L. When the current flowing through inductor L exceeds a preset current threshold, it indicates a short circuit abnormality in inductor L. At this point, the second control circuit 20B can execute relevant inductor abnormality processing operations. In actual applications, the input DC power is affected by actual components and transmission, resulting in the current magnitude not being constant as in ideal conditions. Specifically, due to the irrationality of the power supply voltage waveform and the characteristics of the load, the current exhibits a certain periodic AC fluctuation characteristic, i.e., a ripple current. Ideally, the value of the preset current threshold is calculated based on the rated current value corresponding to inductor L. However, in actual applications, due to the influence of ripple current characteristics, there is a certain error between the actual current value and the ideal current value. Therefore, the value of the preset current threshold designed based on the rated current can be adjusted according to the ripple current variation characteristics of the actual product.

[0058] For example, as shown in FIG6 , taking an inductor L of a certain rated inductance as an example, it can be seen that within the same fixed charging time (i.e., a fixed target duration or a fixed target number of switching cycles), the current value of the short-circuited inductor L rises faster than the current value of the normal inductor L. Taking the rated peak current value of the inductor L as 30A during normal operation as an example, when controlling the switch tube S to be turned on based on the target duration, 4us can be selected as the target duration. After a charging time of 4us, for a normal inductor L, the current value (18A) at the output end of the inductor L is less than the rated peak current value of 30A; for a short-circuited inductor L, the current value (44A) at the output end of the inductor L is greater than the rated peak current value of 30A. The current value of 44A is sufficient to distinguish between abnormal inductance and normal inductance, and will not cause the problem of device loss.

[0059] Exemplarily, there is a fixed calculation conversion formula between the inductance value and the current (such as the above-mentioned current calculation formula based on the inductance characteristics). The judgment on whether the current value flowing through the inductor L is greater than the preset current threshold performed in the above embodiment can also be understood as calculating the current actual inductance value of the inductor L based on the current value at the output end of the inductor L, and judging whether the inductor L is short-circuited based on whether the actual inductance value is less than the preset inductance threshold (according to the above-mentioned current calculation formula, the smaller the inductance value, the larger the current value).

[0060] In some possible implementations, the inductor abnormality handling operation includes controlling the second power conversion device 100B to shut down, outputting inductor abnormality alarm information, or reducing the input power of the inductor L. In the embodiment of the present application, different inductor abnormality handling operations can be adapted and executed after detecting an abnormality in the inductor L, depending on actual product application requirements and application scenarios.

[0061] In some possible implementations, depending on the hardware design of the second control circuit 20B, different forms may be used to trigger the execution of the inductance abnormality processing operation:

[0062] In some examples, as shown in FIG7 , the second control circuit 20B includes a second sampling circuit 21B, an overcurrent protection circuit 22B, and a first control chip 23B. The second sampling circuit 21B is connected to the output end of the inductor L and the overcurrent protection circuit 22B, respectively. The overcurrent protection circuit 22B is also connected to the first control chip 23B. The second sampling circuit 21B is configured to obtain the current value flowing through the inductor L and transmit it to the overcurrent protection circuit 22B. The overcurrent protection circuit 22B is configured to output an abnormality indication signal to the first control chip 23B when the current value flowing through the inductor L is greater than a preset current threshold. The abnormality indication signal is configured to indicate a short circuit between adjacent winding coils of the inductor L. The first control chip 23B is configured to perform an inductor abnormality processing operation based on the abnormality indication signal. In the embodiment of the present application, an overcurrent protection circuit 22B is provided in the second control circuit 20B of the second power conversion device 100B. The overcurrent protection circuit 22B determines whether the current value at the output end of the inductor L is greater than a preset current threshold based on the sampled current, thereby determining an abnormality in the inductor L. When the inductor L is short-circuited, the overcurrent protection circuit 22B can send a corresponding abnormality indication signal to the first control chip 23B. The first control chip 23B performs corresponding inductor abnormality processing operations based on the abnormality indication signal.

[0063] In some examples, as shown in FIG8 , the second control circuit 20B includes a second sampling circuit 21B and a second control chip 24B. The second sampling circuit 21B is connected to the output end of the inductor L and the second control chip 24B, respectively. The second sampling circuit 21B is configured to obtain the current value flowing through the inductor L and transmit it to the overcurrent protection circuit 22B. The second control chip 24B is configured to execute an inductor L abnormality handling operation when the current value flowing through the inductor L is greater than a preset current threshold. In an embodiment of the present application, the second sampling circuit 21B can sample and obtain the current at the output end of the inductor L, and the second control chip 24B determines whether the inductor L is abnormal based on the current magnitude at the output end of the inductor L. When the current value at the output end of the inductor L is greater than the preset current threshold, it indicates that adjacent winding coils of the inductor L are short-circuited, and the second control chip 24B can execute a corresponding inductor abnormality handling operation.

[0064] In some examples, the DC / DC converter circuit 10 can be a DC boost circuit. Exemplarily, the DC boost circuit can be a boost circuit. As shown in FIG9 , the boost circuit 10A includes the inductor L and the switch S described in the above embodiments. In addition, the boost circuit 10A also includes an input capacitor Cin, an output capacitor Cout, a diode D, and the like. The diode D is connected in series with the output end of the inductor L, and the switch S is connected between the inductor L and the diode D. The input capacitor Cin and the output capacitor Cout are each connected in parallel with the switch S, with the input capacitor Cin connected to the input end of the inductor L, and the output capacitor Cout connected to the output end of the diode D. Exemplarily, the input capacitor Cin is connected between the positive input terminal IN+ and the negative input terminal IN- of the DC / DC converter circuit 10. The output capacitor Cout is connected between the positive output terminal OUT+ and the negative output terminal OUT- of the DC / DC converter circuit 10. The diode D is connected between the output end of the inductor L and the positive output terminal OUT+ of the DC / DC converter circuit 10. In the embodiment of the present application, the input capacitor Cin and the output capacitor Cout can respectively implement filtering processing at the input and output ends of the DC / DC converter circuit 10. The diode D can ensure unidirectional conductivity at the output end of the inductor L. After the input capacitor Cin is provided, the voltage at the input capacitor Cin is the input voltage of the DC / DC converter circuit 10.

[0065] In some possible embodiments, the second power conversion device 100B may further include a DC / AC conversion circuit. The input end of the DC / AC conversion circuit is connected to the output end of the DC / DC conversion circuit. The DC / AC conversion circuit is used to convert the DC power at the output end of the inductor L provided by the DC / DC conversion circuit 10 into AC power. As shown in Figure 9, an exemplary circuit topology based on the boost circuit 10A is shown. The positive input end and the negative input end of the DC / AC conversion circuit 30 are respectively connected to the positive output end OUT+ and the negative output end OUT- of the boost circuit. The positive input end IN+ and the negative input end IN- of the boost circuit 10A obtain DC power from the DC power supply 200, and the obtained DC power is filtered by the input capacitor Cin. After the second control circuit 20B controls the switch tube S to conduct via a drive signal, the obtained DC current passes through the inductor L. After the conduction control of the switch tube S and the inductance characteristics of the inductor L are used to achieve a boosted DC power, the boosted DC power is obtained. The boosted DC power is unidirectionally conducted by diode D and flows through the positive output terminal OUT+ and the negative output terminal OUT- of the boost circuit. After filtering by output capacitor Cout, the boosted DC power is transmitted to the DC / AC converter circuit 30. The DC / AC converter circuit 30 inverts the input DC power to generate AC power. This AC power can be supplied to the power grid or an AC load.

[0066] In some possible implementations, the power supply system 1000 may further include components such as a transformer and an AC filter circuit.

[0067] The present application also provides an electric power device, which includes a circuit board and a power conversion device, wherein the power conversion device is disposed on the circuit board. The power conversion device of the electronic device may be the second power conversion device 100B described in the above embodiment. Regarding the relevant technical principles and beneficial effects of providing the second power conversion device 100B in the electric power device, reference may be made to the relevant description of providing the second power conversion device 100B in the power supply system 1000, which will not be repeated here.

[0068] The present application also provides a detection method, which is applied to the second power conversion device 100B including the structures described in the embodiments of Figures 4, 7, 8, and 9. Specifically, the detection method may include the following operations of steps S100 to S200 as shown in Figure 10:

[0069] S100 , during the startup of the second power conversion device 100B, controlling the switch tube S to be continuously turned on within a target duration or controlling the switch tube to be turned on and off within a target number of switching cycles.

[0070] In some possible implementations, during the startup of the second power conversion device 100B, as shown in FIG4 , the second control circuit 20B of the second power conversion device 100B can control the conduction of the switch tube S based on a target duration or a target number of switching cycles to control the charging duration of the inductor L. Under a fixed charging duration, the current flowing through the inductor L has a certain current value. When the inductor L is not short-circuited, the charging duration causes the current value at the output terminal of the inductor L to be less than or equal to the rated peak current value of the inductor L; when the inductor L is short-circuited, the charging duration causes the current value at the output terminal of the inductor L to be greater than the rated peak current value of the inductor L by a certain value. According to the analysis of the embodiment shown in FIG. 5 , by setting a target duration or a target number of switching cycles to control the charging duration of the inductor L, a normal inductor L and a short-circuited inductor L have current signals with different current values ​​under the same charging duration. Furthermore, the target duration or the target number of switching cycles ensures that the current value at the output terminal of the short-circuited inductor L is only a certain value greater than the rated peak current value of the normal inductor L. This ensures that the current at the output terminal of the short-circuited inductor L is insufficient to damage the circuit. In subsequent processing, abnormality detection can be implemented based on the different current values.

[0071] In one example, the rated peak current value is determined by the input voltage of the inductor L, the rated inductance of the inductor L, and the target duration. Alternatively, the rated peak current value is determined by the input voltage of the inductor L, the rated inductance of the inductor L, and the target number of switching cycles. The rated inductance is the inductance value of the inductor L when it is operating normally. Exemplarily, the target duration and the target number of switching cycles are both for determining the duration t1 of the charging current of the inductor L when it is charging. When the inductor L is operating normally, the inductance value of the inductor L is the normal inductance value L1, and the duration of the charging current is fixed at t1. At this time, the corresponding calculation formula for the rated peak current value i1 is: i1 = Upv*t1 / L1.

[0072] In one example, the abnormal peak current value is determined by the input voltage of inductor L, the post-attenuation inductance value of inductor L, and the target duration; alternatively, the rated peak current value is determined by the input voltage of inductor L, the rated inductance value of inductor L, and the target number of switching cycles. The post-attenuation inductance value is the inductance value of inductor L when it is in a short-circuit state. For example, when inductor L is short-circuited, the inductance value of inductor L decays, and the inductance value of inductor L is the post-attenuation inductance value L2. The duration of the charging current is fixed at t1. At this time, the corresponding abnormal peak current value i2 is calculated as follows: i2 = Upv * t1 / L2.

[0073] In one example, as shown in FIG5 , based on the target duration, the value of the preset current threshold a can be set between the rated peak current value i1 and the abnormal peak current value i2 .

[0074] Exemplarily, the first absolute value is equal to the second absolute value. The first absolute value is the absolute value of the difference between the preset current threshold a and the rated peak current value, and the second absolute value is the absolute value of the difference between the preset current threshold and the abnormal peak current value. In the embodiments of the present application, since i1 < a < i2, the equation of the first absolute value and the second absolute value can also be expressed as: (i2 - a) = (a - i1). As can be seen from FIG. 5, in the embodiments of the present application, the preset current threshold a is equal to the differences between the rated peak current value i1 and the abnormal peak current value i2. At this time, the detection result can have relatively high reliability.

[0075] In some possible implementation manners, a corresponding target duration or a target number of switching cycles can be designed according to the preset current threshold a. Exemplarily, taking the design of the preset current threshold a based on the target duration as an example, the rated inductance value of the normal inductor L is L1, and the attenuated inductance value of the short - circuited inductor L is L2. As shown in FIG. 11, the effective conduction duration t2 required for the current value at the output end of the inductor L output by the normal inductor L to reach the preset current threshold a can be calculated. The effective conduction duration t3 required for the current value at the output end of the inductor L output by the short - circuited inductor L to reach the preset current threshold a is calculated. Select a certain duration between time t3 and time t2 (t3 < t2) as the fixed duration t1, that is, the charging current duration.

[0076] Exemplarily, based on the formula i1 = Upv * t1 / L1 and the formula i2 = Upv * t1 / L2, when it is required to satisfy (i2 - a) = (a - i1), the target duration corresponding to the preset current threshold a at this time, that is, the charging current duration t1, can be obtained. The calculation formula of the charging current duration t1 is as follows: t1 = 2a / Upv(1 / L1 + 1 / L2);

[0077] In the formula, a is the preset current threshold a selected to meet the requirement of (i2 - a) = (a - i1), Upv is the input voltage of the DC / DC conversion circuit 10, L1 is the rated inductance value when the inductor L works normally, and L2 is the attenuated inductance value after the inductor L is short - circuited.

[0078] In actual applications, there may be certain calculation errors in the values of parameters such as i1, i2, a, t1, t2, t3, L1, and L2, etc. However, generally within the error range, it is still required to satisfy the requirement of t3 < t1 < t2.

[0079] In some possible implementation manners, the on - control of the switching transistor S can be achieved by using drive signals in different forms:

[0080] In one example, the drive signal can be a high-level signal with a continuous effective pulse width. As shown in Figure 12, the target duration of the drive signal is the charging current duration t1. Under the target duration, the current flowing through the inductor L increases at a fixed rate per unit time.

[0081] In one example, the drive signal can be a level signal with a certain duty cycle. In this case, as shown in Figure 13, the first coordinate system represents the periodic variation of the effective pulse width of the drive signal over time. It can be seen that the drive signal has a certain switching period T. Within this switching period T, according to a preset duty cycle, there is a certain effective pulse width duration tx and a certain low-level duration td. In this case, the total effective pulse width duration can be obtained by summing the effective pulse width durations tx within one or more periods T. This total effective pulse width duration is the duration t1 of the charging current of the inductor L. The second coordinate system is a schematic diagram of the current variation over time of a normal inductor L under the charging current duration t1. The third coordinate system is a schematic diagram of the current variation over time of a short-circuited inductor L under the charging current duration t1. As shown in Figure 13, within a unit time period consisting of a certain number of switching periods T, the duty cycle values ​​within a single switching period T vary (i.e., the ratio between the effective pulse width duration tx and the low-level duration td varies), resulting in different current values ​​flowing through the inductor L per unit time. Therefore, the current flowing through the inductor L can be adjusted based on different duty cycles, thereby adjusting the voltage conversion capability of the DC / DC converter circuit 10. At the same time, when the switch S is controlled to be on based on a target duration, the current flowing through the inductor L will rise to a certain current value in a relatively short period of time. However, when the switch S is controlled to be on based on a target number of switching cycles T, the current flowing through the inductor L will take longer to rise to the same current value as in the target duration scheme. Therefore, controlling the switch S to be on based on the switching cycle T can more easily avoid safety issues caused by excessively rapid current increases, thereby improving detection safety.

[0082] For example, the duty cycle of the switching period of the driving signal may be adjusted based on a pulse width modulation (PWM) technique.

[0083] S200 , detecting a state of the inductor L according to a current value flowing through the inductor L.

[0084] In some possible implementations, when the current flowing through the inductor L is greater than a preset current threshold a, an inductor abnormality handling operation is performed. For example, there is a fixed calculation conversion formula between the inductance value and the current (e.g., the above-mentioned current calculation formula). The determination of whether the current value at the output end of the inductor L is greater than the preset current threshold in the above-mentioned embodiment can also be understood as calculating the current actual inductance value of the inductor L based on the current value flowing through the inductor L, and determining whether the inductor L is short-circuited based on whether the actual inductance value is less than the preset inductance threshold (according to the above-mentioned current calculation formula, the smaller the inductance value, the greater the current).

[0085] In some possible implementations, as shown in FIG. 7 and FIG. 8 , the current at the output end of the inductor L may be sampled and acquired based on the second sampling circuit 21B in the second control circuit 20B.

[0086] In one example, the inductor abnormality handling operation includes controlling the second power conversion device 100B to shut down, outputting inductor abnormality alarm information, or reducing the input power of the inductor L. In the embodiment of the present application, different inductor abnormality handling operations can be adapted and executed after detecting an abnormality in the inductor L, depending on the actual product application requirements and application scenarios.

[0087] For example, when the second control circuit 20B has the structure shown in FIG8 , the second control chip 24B can judge the current value flowing through the inductor L, and when the current value flowing through the inductor L is greater than the preset current threshold a, perform the inductor abnormality processing operation.

[0088] Exemplarily, when the second control circuit 20B has the structure shown in FIG7 , the operation of step S200 may specifically include:

[0089] S210 : When the current value flowing through the inductor L is greater than a preset current threshold, an abnormality indication signal is generated.

[0090] For example, as shown in FIG7 , an overcurrent protection circuit 22B is provided in the second control circuit 20B of the second power conversion device 100B. The overcurrent protection circuit 22B determines whether the inductor L is abnormal based on whether the current flowing through the inductor L is greater than a preset current threshold. When the inductor L is short-circuited, the overcurrent protection circuit 22B can send a corresponding abnormality indication signal to the first control chip 23B. The abnormality indication signal is used to indicate that the inductor L is in an abnormal state.

[0091] S220: Execute an inductance abnormality processing operation according to the abnormality indication signal.

[0092] For example, as shown in FIG7 , the first control chip 23B may perform an inductance abnormality processing operation according to the abnormality indication signal.

[0093] In some possible implementations, when the current flowing through the inductor L is less than or equal to a preset current threshold, the second power conversion device 100B is kept turned on. In the embodiment of the present application, in step S200, when the current flowing through the inductor L is less than or equal to the preset current threshold, it is confirmed that there is no abnormality in the DC side inductance of the second power conversion device 100B. When there are no other abnormalities in the second power conversion device 100B, the second power conversion device 100B can be controlled to start normally.

[0094] The embodiment of the present application uses the detection method described in the embodiments of Figures 10, 11, 12 and 13 to realize fault detection of the inductor L of the power conversion device during the startup process of the second power conversion device 100B, thereby avoiding damage to circuit components caused by a short circuit of the inductor L while ensuring detection accuracy.

[0095] In some possible implementations, after the startup inductance detection of the power conversion device is implemented based on the solution of steps S100 to S200 described above, the inductance L of the power conversion device may be detected during the working phase of the DC / DC conversion circuit 10 of the power conversion device based on the following operations of steps S300 to S500 as shown in FIG14 :

[0096] S300 : Obtaining an operating current value of a current flowing through an inductor L in an operating state.

[0097] In some possible implementations, as shown in FIG4 , when the DC / DC converter circuit 10 of the second power conversion device 100B is in operation, the operating current value of the current flowing through the inductor L is sampled and acquired by the second control circuit 20B shown in FIG4 . For example, as shown in FIG7 , FIG8 , and FIG9 , the current value flowing through the inductor L can be sampled and acquired by a second sampling circuit 21B in the second control circuit.

[0098] S400 : Determine an actual inductance value of the inductor L according to an operating current value of the current flowing through the inductor L.

[0099] In some possible implementations, as shown in FIG4 , the second control circuit 20B can calculate the actual inductance value of the inductor L based on the operating current value of the current flowing through the inductor L, and determine whether the inductor L is abnormal based on the actual inductance value. For example, the calculation of the actual inductance value can be implemented based on the first control chip 23B shown in FIG7 or the second control chip 24B shown in FIG8 .

[0100] In one example, when calculating the actual inductance of the inductor L, the actual inductance can be calculated according to different working condition calculation algorithms based on whether the working current value of the current flowing through the inductor L is a discontinuous inductor current or a continuous inductor current. Exemplarily, the above-mentioned determination of the actual inductance of the inductor L based on the working current value of the current flowing through the inductor L includes: when the working current value of the current flowing through the inductor L is a continuous inductor current, the actual inductance of the inductor L is determined according to the working current value of the current flowing through the inductor L according to the continuous inductor current algorithm. When the working current value of the current flowing through the inductor L is a discontinuous inductor current, the actual inductance of the inductor L is determined according to the discontinuous inductor current algorithm. In this embodiment of the present application, it is possible to match the corresponding calculation method according to different working conditions of the inductor current signal, thereby achieving comprehensive abnormal calculation of the inductor L under different working conditions when it is in a working state.

[0101] S500: Detect the working state of the inductor L according to the actual inductance value.

[0102] In some possible implementations, when the actual inductance value of the inductor L is less than a preset inductance value threshold, an inductance abnormality processing operation is performed. Based on the principle description of the embodiment of Figure 5 above, it can be seen that in the working state, when the input voltage is known, after detecting the working current value of the current flowing through the inductor L, step S400 is used to detect whether the inductor current is in a continuous working condition or a discontinuous working condition, thereby matching the corresponding algorithm to calculate the actual inductance value of the inductor L. According to the principle description of the embodiment of Figure 5, when the inductor L is in a short-circuit state, its inductance value will decay. Therefore, when the actual inductance value is less than a certain preset inductance value threshold, an inductance abnormality processing operation can be performed in the working state of the second power conversion device 100B. For the relevant description of the execution of the inductance abnormality processing operation in step S500, please refer to the description in the previous embodiment and will not be repeated here.

[0103] For example, taking the complete execution of steps S100-S500 as an example, the processing flow of the second control circuit 20B can be shown in FIG15 . First, during the startup process of the second power conversion device 100B, the second control circuit 20B can control the DC / DC converter circuit 10 to generate a pulse using a fixed target duration or a fixed target number of switching cycles, so that current flows through the output end of the inductor L. The target duration or target switching rate ensures that, when the inductor L is operating normally, the current flowing through the inductor L is close to the rated peak current value of the inductor L, and when the inductor L is short-circuited, the current flowing through the inductor L is greater than the rated peak current value by a certain range. Based on this operation, abnormal inductances can be distinguished while ensuring device safety. In step S200, the operating current value (or inductance value) of the current flowing through the inductor L can be calculated. Based on the calculation result and a comparison with a preset threshold, it can be determined during the startup process of the second power conversion device 100B whether the inductor L on its DC side is an abnormal short-circuited inductor. If the inductor L is determined to be an abnormal short-circuited inductor, an inductor abnormality handling operation can be performed. If the inductor L is determined to be normal and the second power conversion device 100B has no other faults or problems, the second power conversion device 100B can be controlled to start and operate normally. Then, while the second power conversion device 100B is operating normally, the operating current value of the current flowing through the inductor L when the DC / DC converter circuit 10 is in operation can be sampled and acquired in step S300. In step S400, the actual inductance value in the operating state is calculated. When calculating the actual inductance value, the inductor current can be tested for continuity, and a corresponding calculation method can be used based on the test results. Then, in step S500, whether the inductor L is normal is determined based on whether the actual inductance value is less than a certain threshold. When the actual inductance value of the inductor L is greater than or equal to the certain threshold, it indicates that the inductor is normal, confirming that there are no faults in this test. When the actual inductance value of the inductor L is less than the certain threshold, it indicates that the inductor is short-circuited, indicating that an abnormal inductor fault has occurred in this test, and the corresponding inductor abnormality handling operation can be performed.

[0104] In an embodiment of the present application, the inductance on the DC side of the power conversion device is detected during the startup phase through steps S100 to S200. In addition, in the steps S300 to S500, the inductance on the DC side of the power conversion device is detected when the DC / DC conversion circuit is in the working phase. Based on the above steps, the inductance detection on the DC side of the power conversion device can be realized in the entire working process. In addition, when the inductance detection during operation is performed in the steps S300 to S500, a distinction is made based on whether the inductance current is a discontinuous current or a continuous current, and different calculation methods are adapted based on the distinction. Based on the embodiment of the present application, systematic inductance detection of the power conversion device on the DC side under all working conditions and in all stages can be realized, thereby improving the working safety and reliability of the DC side.

[0105] An embodiment of the present application also provides a computer-readable storage medium, which includes instructions. When the instructions are executed on a control chip, the processor or control chip executes the detection method described in the above embodiments (for example, the detection method described in Figures 10, 11, 12, 13, 14 and 15).

[0106] The control chip involved in the embodiments of the present application can be a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD) or other integrated chips.

[0107] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean 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 application.

[0108] Those skilled in the art will appreciate that the modules and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0109] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and modules described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0110] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0111] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located on a single device or distributed across multiple devices. Some or all of the modules may be selected to achieve the purpose of this embodiment based on actual needs.

[0112] In addition, the functional modules in the various embodiments of the present application may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0113] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using a software program, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loading and executing computer program instructions on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode to another website, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more media that can be integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0114] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A power conversion device, characterized in that: The device comprises a control circuit and a DC / DC conversion circuit; the DC / DC conversion circuit comprises an inductor and a switch tube; the switch tube is connected in parallel with a DC power supply, and the inductor is connected in series in a loop formed by the DC power supply and the switch tube; wherein the control circuit is used to: During the startup of the power conversion device, controlling the switch tube to be continuously turned on for a target duration or controlling the switch tube to be turned on and off within a target number of switching cycles; After the target time or the target number of switching cycles, when the current value flowing through the inductor is greater than a preset current threshold, an inductor abnormality processing operation is performed.

2. The power conversion device according to claim 1, characterized in that: The control circuit includes a sampling circuit, an overcurrent protection circuit and a control chip; the sampling circuit is connected to the inductor and the overcurrent protection circuit respectively; the overcurrent protection circuit is also connected to the control chip; wherein: The sampling circuit is used to: obtain the current value flowing through the inductor and transmit it to the overcurrent protection circuit; The overcurrent protection circuit is configured to: output an abnormal indication signal to the control chip when the current value flowing through the inductor is greater than the preset current threshold; The control chip is used to: execute the inductance abnormality processing operation according to the abnormality indication signal.

3. The power conversion device according to claim 1, wherein: The control circuit includes a sampling circuit and a control chip; the sampling circuit is connected to the inductor and the control chip respectively; wherein: The sampling circuit is used to: obtain the current value flowing through the inductor and transmit it to the overcurrent protection circuit; The control chip is used to: when the current value flowing through the inductor is greater than the preset current threshold, execute the inductor abnormality processing operation.

4. The power conversion device according to any one of claims 1 to 3, characterized in that: The preset current threshold is greater than a rated peak current value, and the rated peak current value is determined by the input voltage of the inductor, the rated inductance of the inductor, and the target duration, or the rated peak current value is determined by the input voltage of the inductor, the rated inductance of the inductor, and the target number of switching cycles; the rated inductance value is the inductance value of the inductor when it is working normally.

5. The power conversion device according to claim 4, characterized in that: The preset current threshold is also smaller than the abnormal peak current value, and the abnormal peak current value is determined by the input voltage of the inductor, the post-attenuation inductance value of the inductor, and the target duration, or the abnormal peak current value is determined by the input voltage of the inductor, the post-attenuation inductance value of the inductor, and the target number of switching cycles; the post-attenuation inductance value is the inductance value of the inductor when adjacent winding coils are short-circuited.

6. The power conversion device according to claim 5, characterized in that: The first absolute value is equal to the second absolute value, the first absolute value is the absolute value of the difference between the preset current threshold and the rated peak current value, and the second absolute value is the absolute value of the difference between the preset current threshold and the abnormal peak current value.

7. The power conversion device according to any one of claims 1 to 6, characterized in that: The control circuit is further configured to: When the current flowing through the inductor is less than or equal to the preset current threshold, the power conversion device is kept turned on.

8. The power conversion device according to any one of claims 1 to 7, characterized in that: The DC / DC conversion circuit is a boost circuit.

9. The power conversion device according to any one of claims 1 to 8, characterized in that: The power conversion device further includes a DC / AC conversion circuit, and an input end of the DC / AC conversion circuit is connected to an output end of the DC / DC conversion circuit.

10. The power conversion device according to any one of claims 1 to 9, characterized in that: The inductance abnormality processing operation includes: The power conversion device is controlled to shut down, output an inductor abnormality alarm message, or reduce the input power of the inductor.

11. A detection method, characterized in that: Applicable to a power conversion device; the power conversion device includes a DC / DC conversion circuit; the DC / DC conversion circuit includes an inductor and a switch tube; the switch tube is used to be connected in parallel with a DC power supply, and the inductor is connected in series in a loop formed by the DC power supply and the switch tube; wherein the method includes: During the startup of the power conversion device, controlling the switch tube to be continuously turned on for a target duration or controlling the switch tube to be turned on and off within a target number of switching cycles; After the target time or the target number of switching cycles, when the current value flowing through the inductor is greater than a preset current threshold, an inductor abnormality processing operation is performed.

12. The detection method according to claim 11, characterized in that When the current value flowing through the inductor is greater than the preset current threshold, performing an inductor abnormality processing operation includes: When the current value flowing through the inductor is greater than the preset current threshold, an abnormal indication signal is obtained; The inductance abnormality processing operation is performed according to the abnormality indication signal.

13. The detection method according to claim 11 or 12, characterized in that: The preset current threshold is greater than a rated peak current value, and the rated peak current value is determined by the input voltage of the inductor, the rated inductance of the inductor, and the target duration, or the rated peak current value is determined by the input voltage of the inductor, the rated inductance of the inductor, and the target number of switching cycles; the rated inductance value is the inductance value of the inductor when it is working normally.

14. The detection method according to claim 13, characterized in that The preset current threshold is also smaller than an abnormal peak current value, where the abnormal peak current value is determined by the input voltage of the inductor, the post-attenuation inductance value of the inductor, and the target duration; or, the abnormal peak current value is determined by the input voltage of the inductor, the post-attenuation inductance value of the inductor, and the target number of switching cycles, where the post-attenuation inductance value is the inductance value of the inductor when adjacent winding coils are short-circuited.

15. The detection method according to claim 14, characterized in that: The first absolute value is equal to the second absolute value, the first absolute value is the absolute value of the difference between the preset current threshold and the rated peak current value, and the second absolute value is the absolute value of the difference between the preset current threshold and the abnormal peak current value.

16. The detection method according to any one of claims 11 to 15, characterized in that: The method further comprises: When the current flowing through the inductor is less than or equal to the preset current threshold, the power conversion device is kept turned on.

17. The detection method according to any one of claims 11 to 16, characterized in that: The inductor abnormality processing operation includes controlling the power conversion device to shut down, outputting inductor abnormality alarm information, or reducing the input power of the inductor.

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