CN112688550A - Method, system and device for judging failure of interleaved PFC circuit - Google Patents
Method, system and device for judging failure of interleaved PFC circuit Download PDFInfo
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- CN112688550A CN112688550A CN202011314850.0A CN202011314850A CN112688550A CN 112688550 A CN112688550 A CN 112688550A CN 202011314850 A CN202011314850 A CN 202011314850A CN 112688550 A CN112688550 A CN 112688550A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention relates to the technical field of interleaved PFC circuit failure judgment, and particularly provides a method, a system and a device for judging the failure of an interleaved PFC circuit, aiming at solving the problems of quickly and accurately judging the failure of a PFC branch and ensuring the operation safety of a plurality of PFC circuits. To this end, the method of the invention comprises the following steps: connecting a plurality of PFC branches to an inverter from a rectifier bridge; obtaining the current of a shunt resistor in each PFC branch in a plurality of PFC branches; comparing the current of the shunt resistor in each PFC branch circuit with a first threshold current to judge whether one PFC branch circuit where the current is located has a fault; and limiting the frequency of the compressor according to the judgment result. Under the condition of adopting the method, the invention can quickly and accurately judge the fault and the fault quantity of the PFC branches, further limit the frequency of the compressor, avoid the PFC faults of other branches caused by long-time operation and realize the guarantee of the operation safety of a multi-path PFC circuit.
Description
Technical Field
The invention relates to the technical field of interleaved PFC circuit failure judgment, in particular to a method, a system and a device for judging the interleaved PFC circuit failure.
Background
The Power Factor Correction (PFC) refers to a relationship between an effective Power and a total Power consumption (Power), that is, a ratio of the effective Power divided by the total Power consumption (Power). Basically, the power factor can measure the effective utilization degree of the power, and when the power factor value is larger, the power utilization rate is higher; the power factor is a parameter for measuring the power efficiency of the electric equipment, and the low power factor represents the low power efficiency. A technique for increasing the power factor of a powered device is known as power factor correction. In the prior art, when a PFC circuit is damaged, a machine can report faults, but which branch fails to be accurately judged, if one or more paths of a plurality of paths of staggered PFC circuits fail, the current of the rest PFC branches is too large and exceeds a rated design value, and the PFC faults of the rest branches can cause more serious consequences after long-time operation.
Therefore, a scheme for judging the failure of the interleaved PFC circuit is required to be provided, which can quickly and accurately judge the number of the PFC branches having faults and the number of the faults, so as to limit the frequency of the compressor and ensure the operation safety of the multiple PFC circuits.
Disclosure of Invention
In order to overcome the defects, the invention is provided to solve or at least partially solve the technical problems of quickly and accurately judging the failure of the PFC branch, thereby performing frequency-limited operation on the compressor and ensuring the operation safety of a multi-path PFC circuit. The invention provides a method, a system and a device for judging the failure of an interleaved PFC circuit to solve the technical problems.
In a first aspect, a method for determining a failure of an interleaved PFC circuit is provided,
connecting a plurality of PFC branches to an inverter from a rectifier bridge;
obtaining the current of a shunt resistor in each PFC branch in a plurality of PFC branches;
comparing the current of the shunt resistor in each PFC branch circuit with a first threshold current to judge whether one PFC branch circuit where the current is located has a fault;
and limiting the frequency of the compressor according to the judgment result.
The "obtaining the current of the shunt resistor in each PFC branch in the multiple PFC branches" specifically includes:
collecting the currents of all PFC branches of the multi-path PFC branches, and judging whether the sum of the currents of all PFC branches is larger than or equal to a preset second threshold value;
if so, performing "comparing the current of the shunt resistor in each PFC branch with the first threshold current".
The "comparing the current of the shunt resistor in each PFC branch with a preset first threshold current to determine whether a PFC branch in which the current is located has a fault" specifically includes:
if one or more of the obtained currents of all the PFC branches are smaller than or equal to the first threshold current, and the currents of the other PFC branches are larger than the first threshold current, determining that one or more of the currents corresponding to one or more PFC branches have faults;
"according to the said judged result, carry on the frequency limitation to the compressor", include specifically:
and limiting the frequency of the compressor according to the number of the PFC branches with faults.
The first threshold current is a preset fixed current value;
alternatively, the first and second electrodes may be,
the first threshold current is a dynamic current value, and a calculation formula is as follows:
Irefn＝Kn×(I1+I2+...+In)
wherein, for a multi-path PFC circuit with n branches, IrefnIs a preset threshold current; knThe general value is 1/n; i isnThe collected current value of the shunt resistor R passing through the nth branch circuit is obtained;
the "limiting the frequency of the compressor according to the judgment result" specifically includes:
if m branches in the multi-path PFC circuits of the n branches have faults, the frequency limiting current value of the compressor is reduced by m/n.
In a second aspect, a system for determining failure of an interleaved PFC circuit is provided,
the interleaved PFC circuit comprises a plurality of PFC branches connected to an inverter;
the acquisition module is used for acquiring the current of the shunt resistor in each PFC branch in the multiple PFC branches;
the judging module is used for comparing the current of the shunt resistor in each PFC branch circuit with a first threshold current so as to judge whether one PFC branch circuit where the current is located has a fault;
and the frequency limiting module is used for limiting the frequency of the compressor according to the judgment result.
The acquisition module specifically executes the following operations:
collecting the currents of all PFC branches of the multi-path PFC branches, and judging whether the sum of the currents of all PFC branches is larger than or equal to a preset second threshold value;
if yes, entering a judging module to execute operation;
the judging module specifically executes the following operations:
if one or more of the obtained currents of all the PFC branches are smaller than or equal to the first threshold current, and the currents of the other PFC branches are larger than the first threshold current, determining that one or more of the currents corresponding to one or more PFC branches have faults;
the frequency limiting module specifically executes the following operations:
and limiting the frequency of the compressor according to the number of the PFC branches with faults.
The first threshold current is a preset fixed current value;
alternatively, the first and second electrodes may be,
the first threshold current is a dynamic current value, and a calculation formula is as follows:
Irefn＝Kn×(I1+I2+...+In)
wherein, for a multi-path PFC circuit with n branches, IrefnIs a preset threshold current; knThe general value is 1/n; i isnThe collected current value of the shunt resistor R passing through the nth branch circuit is obtained;
the frequency limiting module specifically further performs the following operations:
if m branches in the multi-path PFC circuits of the n branches have faults, the frequency limiting current value of the compressor is reduced by m/n.
The multi-path PFC branch specifically comprises: each PFC branch is connected to one end of a branch inductor from a rectifier bridge, the other end of the branch inductor L is respectively connected to one end of a branch diode D and a drain electrode of a branch switching tube Q, the other end of the branch diode D is connected to one end of a capacitor C1, the other end of the capacitor C1 is respectively connected to one end of a shunt resistor R of each PFC branch and the rectifier bridge, and the other end of the shunt resistor R of each PFC branch is connected to a source electrode of the branch switching tube Q; and the multi-path PFC branch is composed of at least two branches in parallel.
In a third aspect, a computer-readable storage medium is provided, in which a plurality of program codes are stored, and the program codes are adapted to be loaded and executed by a processor to execute the method for determining the failure of the interleaved PFC circuit according to any of the foregoing embodiments.
In a fourth aspect, a processing apparatus is provided, which includes a processor and a memory, the memory is adapted to store a plurality of program codes, and the program codes are adapted to be loaded and executed by the processor to execute the method for determining the failure of the interleaved PFC circuit according to any of the preceding claims.
One or more technical schemes of the invention at least have one or more of the following beneficial effects: the invention connects a plurality of PFC branches to an inverter from a rectifier bridge; obtaining the current of a shunt resistor in each PFC branch in a plurality of PFC branches; comparing the current of the shunt resistor in each PFC branch circuit with a first threshold current to judge whether one PFC branch circuit where the current is located has a fault; and limiting the frequency of the compressor according to the judgment result.
Specifically, for a three-phase interleaved PFC circuit, the currents of all three PFC branches of the three-phase PFC branches are collected, and whether the sum of the currents of the three PFC branches is larger than or equal to a preset second threshold current is judged; if a certain phase of current of the collected PFC is smaller than or equal to a first threshold current and the PFC currents of the other two phases are larger than the first threshold current, the PFC circuit of the phase with the small current is considered to be in fault, and the frequency limiting current of the compressor is reduced by 33.3%; if the two phases of PFC currents are smaller than or equal to the first threshold current and the PFC current of the other phase is larger than the first threshold current, the PFC circuits of the two phases with small currents are considered to be in fault, and only one phase works normally, the frequency limiting current of the compressor is reduced by 66.6%. For the two-phase interleaved PFC circuit, the currents of all two PFC branches of the two-phase PFC branches are collected, and whether the sum of the currents of the two PFC branches is larger than or equal to a preset second threshold current is judged; if a certain phase of current of the collected PFC is smaller than or equal to a first threshold current and the PFC current of the other phase is larger than the first threshold current, the PFC circuit of the phase with the small current is considered to be in fault, and the frequency limiting current of the compressor is reduced by 50%;
according to the scheme, the PFC branch circuit fault and the fault number can be judged quickly and accurately, the frequency of the compressor is limited, the PFC faults of other branch circuits caused by long-time operation are avoided, and the operation safety of a multi-path PFC circuit is guaranteed.
Drawings
FIG. 1 is a main flowchart of an embodiment of a method for determining a failure of an interleaved PFC circuit according to the present invention;
fig. 2 is a schematic diagram of one embodiment of a three-phase interleaved PFC circuit in accordance with aspects of the present invention;
fig. 3 is a block diagram of an embodiment of a system for determining failure of an interleaved PFC circuit according to the present invention.
Detailed Description
For the purpose of facilitating understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and examples, but it will be understood by those skilled in the art that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of the present invention.
In the description of the present invention, a "module" or "processor" may include hardware, software, or a combination of both. A module may comprise hardware circuitry, various suitable sensors, communication ports, memory, may comprise software components such as program code, or may be a combination of software and hardware. The processor may be a central processing unit, microprocessor, image processor, digital signal processor, or any other suitable processor. The processor has data and/or signal processing functionality. The processor may be implemented in software, hardware, or a combination thereof. Non-transitory computer readable storage media include any suitable medium that can store program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random-access memory, and the like. The term "a and/or B" denotes all possible combinations of a and B, such as a alone, B alone or a and B. The term "at least one A or B" or "at least one of A and B" means similar to "A and/or B" and may include only A, only B, or both A and B. The singular forms "a", "an" and "the" may include the plural forms as well.
PFC (Power Factor corrector) power Factor correction can improve the utility ratio of the power supply to the mains supply when AC is converted into DC, reduce the electric energy loss in the conversion process and achieve the purpose of energy saving. In addition, the PFC can reduce the interference of the power supply to the mains grid, in particular avoiding the impact on other appliances at a sudden start. PFCs are classified into active (active) and passive (passive), which are important factors in measuring the level of a power supply. In the prior art, when a PFC circuit is damaged, a machine can report faults, but which branch fails to be judged accurately, if one or more paths of a plurality of paths of staggered PFC circuits fail, the current of the rest PFC branches is too large and exceeds a rated design value, and the PFC faults of the rest branches can cause more serious consequences after long-time operation.
The invention relates to an embodiment of a judgment scheme for the failure of an interleaved PFC circuit, which comprises the following steps: collecting a current value passing through a shunt resistor R; comparing the acquired current value with a preset threshold current, and judging whether the multiple PFC circuits have faults or not and the number of branch faults; and limiting the frequency of the compressor according to the number of the branch faults. Specifically, for a three-phase interleaved PFC circuit, the currents of all three PFC branches of the three-phase PFC branches are collected, and whether the sum of the currents of the three PFC branches is larger than or equal to a preset second threshold current is judged; if a certain phase of current of the collected PFC is smaller than or equal to a first threshold current and the PFC currents of the other two phases are larger than the first threshold current, the PFC circuit of the phase with the small current is considered to be in fault, and the frequency limiting current of the compressor is reduced by 33.3%; if the two phases of PFC currents are smaller than or equal to the first threshold current and the PFC current of the other phase is larger than the first threshold current, the PFC circuits of the two phases with small currents are considered to be in fault, and only one phase works normally, the frequency limiting current of the compressor is reduced by 66.6%. For the two-phase interleaved PFC circuit, the currents of all two PFC branches of the two-phase PFC branches are collected, and whether the sum of the currents of the two PFC branches is larger than or equal to a preset second threshold current is judged; if a certain phase of current of the collected PFC is smaller than or equal to a first threshold current and the PFC current of the other phase is larger than the first threshold current, the PFC circuit of the phase with the small current is considered to be in fault, and the frequency limiting current of the compressor is reduced by 50%; therefore, the fault and the fault number of the PFC branches can be judged quickly and accurately, the frequency of the compressor is limited, the PFC faults of other branches caused by long-time operation are avoided, and the operation safety of a multi-path PFC circuit is guaranteed.
The following describes an implementation of the present invention with reference to a main flowchart of an embodiment of a method for determining a failure of an interleaved PFC circuit according to the present invention shown in fig. 1.
Step S110, obtaining the current of shunt resistor in each PFC branch in the multiple PFC branches;
the multi-path PFC branch specifically comprises: each PFC branch is connected to one end of a branch inductor from a rectifier bridge, the other end of the branch inductor L is respectively connected to one end of a branch diode D and a drain electrode of a branch switching tube Q, the other end of the branch diode D is connected to one end of a capacitor C1, the other end of the capacitor C1 is respectively connected to one end of a shunt resistor R of each PFC branch and the rectifier bridge, and the other end of the shunt resistor R of each PFC branch is connected to a source electrode of the branch switching tube Q; and the multi-path PFC branch is composed of at least two branches in parallel.
Preferably, as shown in fig. 2, fig. 2 is a schematic diagram of one embodiment of a three-phase interleaved PFC circuit according to aspects of the present invention; the multi-path PFC branch consists of three branches in parallel: each PFC branch is connected to one end of a branch inductor L1, L2, L3 from a rectifier bridge BG1, the other end of the branch inductor L1, L2, L3 is connected to one end of a branch diode D1, D2, D3 and the drain of a branch switching tube Q1, Q2, Q3 respectively, the other end of the branch diode D1, D2, D3 is connected to one end of a capacitor C1, the other end of the capacitor C1 is connected to one end of a shunt resistor R1, R2, R3 of each PFC branch and the rectifier bridge BG1 respectively, and the other end of the shunt resistor R1, R2, R3 of each PFC branch is connected to the source of the branch switching tube Q1, Q2, Q3.
Preferably, the two-phase interleaved PFC circuit is such that the multi-path PFC branch consists of two branches in parallel: each PFC branch is connected to one end of a branch inductor L1, L2 from a rectifier bridge BG1, the other end of the branch inductor L1, L2 is connected to one end of a branch diode D1, D2 and the drain of a branch switching tube Q1, Q2, the other end of the branch diode D1, D2 is connected to one end of a capacitor C1, the other end of the capacitor C1 is connected to one end of a shunt resistor R1, R2 and a rectifier bridge BG1 of each PFC branch, and the other end of a shunt resistor R1, R2 of each PFC branch is connected to the source of a branch switching tube Q1, Q2.
In one embodiment, the currents of all PFC branches of the multiple PFC branches are collected, and whether the sum of the currents of all PFC branches is greater than or equal to a preset second threshold value is determined; if so, performing "comparing the current of the shunt resistor in each PFC branch with the first threshold current".
For example, whether the sum of the currents of all the PFC branches is greater than or equal to a preset second threshold value is judged by collecting the currents of all the PFC branches of the multiple PFC branches; the second threshold value can be preset and is generally about 1A; if yes, the current of the shunt resistor in each PFC branch is compared with the first threshold current.
Step S120, comparing the current of the shunt resistor in each PFC branch with a first threshold current to judge whether one PFC branch where the current is located has a fault;
in one embodiment, if one or more of the obtained currents of all PFC branches are smaller than or equal to the first threshold current, and the currents of the remaining PFC branches are greater than the first threshold current, it is determined that one or more of the currents correspond to one or more PFC branches and a fault occurs;
the first threshold current is a preset fixed current value;
alternatively, the first threshold current is a dynamic current value,
the calculation formula is as follows:
Irefn＝Kn×(I1+I2+...+In)
wherein, for a multi-path PFC circuit with n branches,
Irefnis a preset threshold current;
Knthe value is 1/n generally, and can be adjusted according to the actual situation;
Inthe collected current value passing through the shunt resistor R of the nth branch is obtained.
For a three-phase interleaved PFC circuit, the currents I1, I2, I3 of each phase of PFC are collected in real time, and when the sum of I1+ I2+ I3 is greater than a second threshold current, the judgment is started: comparing the collected currents I1, I2 and I3 of each phase of PFC with a first threshold current Iref3, where Iref3 is K3 × (I1+ I2+ I3), and K3 is a proportionality coefficient (generally 1/3, which can be adjusted according to actual conditions); if a certain phase current of the collected PFC is smaller than or equal to the first threshold current Iref3, and the PFC currents of the other two phases are larger than the first threshold current Iref3, the PFC circuit of the phase with the small current is considered to be in fault; if the current of two phases of the PFC is smaller than or equal to the first threshold current Iref3, and the PFC current of the other phase is larger than the first threshold current Iref3, the PFC circuit of the two phases with small current is considered to be in fault, and only one phase works normally.
For example, when the collected current I1 is 3.5A, I2 is 6.5A, and I3 is 8A, when the sum of the current values of the three branches I1+ I2+ I3 is greater than the second threshold current, the judgment is started, the first threshold current value Iref3 is 6A, and the first threshold current value Iref3 is calculated according to the formula, since I1 < Iref3, I2 > Iref3, and I3 > Iref3, it can be judged that the circuit of the first phase branch fails, and the number of the circuit branch failures is 1. For another example, when the collected current I1 is 3.5A, I2 is 4.5A, and I3 is 10A, the first threshold current value is Iref3 is 6A calculated according to the formula, and since I1 < Iref3, I2 < Iref3, and I3 > Iref3, it can be determined that the first and second phase branch circuits fail, and the number of circuit branch failure faults is 2.
For a two-phase interleaved PFC circuit, the current I1, I2 of each phase PFC is collected in real time, when the sum of the current values of the two branches I1+ I2 is greater than a second threshold current, the judgment is started, the collected current I1, I2 of each phase PFC is compared with the first threshold current Iref2, Iref2 is K2 × (I1+ I2), and K2 is a proportionality coefficient (generally 1/2, which can be adjusted according to actual conditions); if a certain phase current of the collected PFC is smaller than or equal to the first threshold current Iref2, and the PFC current of another phase is larger than the first threshold current Iref2, the PFC circuit of the phase with small current is considered to be in fault.
For example, when the collected current I1 is 3A, I2 is 5A, and the first threshold current Iref2 is 4A, when the sum of the current values of the two I1+ I2 branches is greater than the second threshold current, the judgment is started, and since I1 < Iref2, I2 > Iref2, it can be judged that the circuit of the first phase branch fails, and the number of the circuit branch failures is 1.
And step S130, limiting the frequency of the compressor according to the judgment result.
In one embodiment, when m branches of the n branches in the interleaved PFC circuit fail, the frequency-limited current of the compressor is reduced by m/n.
For example, one of three branches in the three-phase PFC circuit fails, and the frequency-limited current of the compressor is reduced by 33.3%; if two of three branches in the three-phase PFC circuit break down, the frequency-limited current of the compressor is reduced by 66.6%; one of two branches in the two-phase PFC circuit is in fault, and the frequency-limited current of the compressor is reduced by 50%.
The following describes an implementation of the present invention with reference to fig. 3, which is a block diagram of an embodiment of a system for determining a failure of an interleaved PFC circuit according to the present invention. The system at least comprises:
the acquisition module 310 is configured to acquire a current of a shunt resistor in each PFC branch in the multiple PFC branches;
in one embodiment, the multiple PFC branches specifically include: each PFC branch is connected to one end of a branch inductor from a rectifier bridge, the other end of the branch inductor L is respectively connected to one end of a branch diode D and a drain electrode of a branch switching tube Q, the other end of the branch diode D is connected to one end of a capacitor C1, the other end of the capacitor C1 is respectively connected to one end of a shunt resistor R of each PFC branch and the rectifier bridge, and the other end of the shunt resistor R of each PFC branch is connected to a source electrode of the branch switching tube Q; and the multi-path PFC branch is composed of at least two branches in parallel.
Preferably, as shown in fig. 2, fig. 2 is a schematic diagram of one embodiment of a three-phase interleaved PFC circuit according to aspects of the present invention; the multi-path PFC branch consists of three branches in parallel: each PFC branch is connected to one end of a branch inductor L1, L2, L3 from a rectifier bridge BG1, the other end of the branch inductor L1, L2, L3 is connected to one end of a branch diode D1, D2, D3 and the drain of a branch switching tube Q1, Q2, Q3 respectively, the other end of the branch diode D1, D2, D3 is connected to one end of a capacitor C1, the other end of the capacitor C1 is connected to one end of a shunt resistor R1, R2, R3 of each PFC branch and the rectifier bridge BG1 respectively, and the other end of the shunt resistor R1, R2, R3 of each PFC branch is connected to the source of the branch switching tube Q1, Q2, Q3.
Preferably, the two-phase interleaved PFC circuit is such that the multi-path PFC branch consists of two branches in parallel: each PFC branch is connected to one end of a branch inductor L1, L2 from a rectifier bridge BG1, the other end of the branch inductor L1, L2 is connected to one end of a branch diode D1, D2 and the drain of a branch switching tube Q1, Q2, the other end of the branch diode D1, D2 is connected to one end of a capacitor C1, the other end of the capacitor C1 is connected to one end of a shunt resistor R1, R2 and a rectifier bridge BG1 of each PFC branch, and the other end of a shunt resistor R1, R2 of each PFC branch is connected to the source of a branch switching tube Q1, Q2.
In one embodiment, the currents of all PFC branches of the multiple PFC branches are collected, and whether the sum of the currents of all PFC branches is greater than or equal to a preset second threshold value is determined; if so, performing "comparing the current of the shunt resistor in each PFC branch with the first threshold current".
For example, whether the sum of the currents of all the PFC branches is greater than or equal to a preset second threshold value is judged by collecting the currents of all the PFC branches of the multiple PFC branches; the second threshold value can be preset and is generally about 1A; if yes, the current of the shunt resistor in each PFC branch is compared with the first threshold current.
The determining module 320 is configured to compare a current of a shunt resistor in each PFC branch with a first threshold current to determine whether a fault occurs in one PFC branch where the current is located;
in one embodiment, if one or more of the obtained currents of all PFC branches are smaller than or equal to the first threshold current, and the currents of the remaining PFC branches are greater than the first threshold current, it is determined that one or more of the currents correspond to one or more PFC branches and a fault occurs;
the first threshold current is a preset fixed current value;
alternatively, the first threshold current is a dynamic current value,
the calculation formula is as follows:
Irefn＝Kn×(I1+I2+...+In)
wherein, for a multi-path PFC circuit with n branches,
Irefnis a preset threshold current;
Knthe value is 1/n generally, and can be adjusted according to the actual situation;
Inthe collected current value passing through the shunt resistor R of the nth branch is obtained.
For a three-phase interleaved PFC circuit, the currents I1, I2, I3 of each phase of PFC are collected in real time, and when the sum of I1+ I2+ I3 is greater than a second threshold current, the judgment is started: comparing the collected currents I1, I2 and I3 of each phase of PFC with a first threshold current Iref3, where Iref3 is K3 × (I1+ I2+ I3), and K3 is a proportionality coefficient (generally 1/3, which can be adjusted according to actual conditions); if a certain phase current of the collected PFC is smaller than or equal to the first threshold current Iref3, and the PFC currents of the other two phases are larger than the first threshold current Iref3, the PFC circuit of the phase with the small current is considered to be in fault; if the current of two phases of the PFC is smaller than or equal to the first threshold current Iref3, and the PFC current of the other phase is larger than the first threshold current Iref3, the PFC circuit of the two phases with small current is considered to be in fault, and only one phase works normally.
For example, when the collected current I1 is 3.5A, I2 is 6.5A, and I3 is 8A, when the sum of the current values of the three branches I1+ I2+ I3 is greater than the second threshold current, the judgment is started, the first threshold current value Iref3 is 6A, and the first threshold current value Iref3 is calculated according to the formula, since I1 < Iref3, I2 > Iref3, and I3 > Iref3, it can be judged that the circuit of the first phase branch fails, and the number of the circuit branch failures is 1. For another example, when the collected current I1 is 3.5A, I2 is 4.5A, and I3 is 10A, the first threshold current value is Iref3 is 6A calculated according to the formula, and since I1 < Iref3, I2 < Iref3, and I3 > Iref3, it can be determined that the first and second phase branch circuits fail, and the number of circuit branch failure faults is 2.
For a two-phase interleaved PFC circuit, the current I1, I2 of each phase PFC is collected in real time, when the sum of the current values of the two branches I1+ I2 is greater than a second threshold current, the judgment is started, the collected current I1, I2 of each phase PFC is compared with the first threshold current Iref2, Iref2 is K2 × (I1+ I2), and K2 is a proportionality coefficient (generally 1/2, which can be adjusted according to actual conditions); if a certain phase current of the collected PFC is smaller than or equal to the first threshold current Iref2, and the PFC current of another phase is larger than the first threshold current Iref2, the PFC circuit of the phase with small current is considered to be in fault.
For example, when the collected current I1 is 3A, I2 is 5A, and the first threshold current Iref2 is 4A, when the sum of the current values of the two I1+ I2 branches is greater than the second threshold current, the judgment is started, and since I1 < Iref2, I2 > Iref2, it can be judged that the circuit of the first phase branch fails, and the number of the circuit branch failures is 1.
And a frequency limiting module 330, configured to limit the frequency of the compressor according to the determination result.
In one embodiment, when m branches of the n branches in the interleaved PFC circuit fail, the frequency-limited current of the compressor is reduced by m/n.
For example, one of three branches in the three-phase PFC circuit fails, and the frequency-limited current of the compressor is reduced by 33.3%; if two of three branches in the three-phase PFC circuit break down, the frequency-limited current of the compressor is reduced by 66.6%; one of two branches in the two-phase PFC circuit is in fault, and the frequency-limited current of the compressor is reduced by 50%.
Further, in one embodiment of a computer-readable storage medium of the present invention, includes: the storage medium stores a plurality of program codes, and the program codes are suitable for being loaded and executed by a processor to execute the method for judging the failure of the interleaved PFC circuit.
Further, in an embodiment of a processing apparatus of the present invention, the processing apparatus includes a processor and a memory, and the memory is adapted to store a plurality of program codes, and the program codes are adapted to be loaded and executed by the processor to execute the foregoing method for determining the failure of the interleaved PFC circuit.
An example of an application scenario of the technical solution of the present invention is described below to further illustrate the implementation of the present invention: the three-phase staggered PFC circuit of an air conditioner of a certain manufacturer is composed of three branches, as shown in fig. 2, the multi-path PFC branch is composed of three branches in parallel: each PFC branch is connected to one end of a branch inductor L1, L2, L3 from a rectifier bridge BG1, the other end of the branch inductor L1, L2, L3 is connected to one end of a branch diode D1, D2, D3 and the drain of a branch switching tube Q1, Q2, Q3 respectively, the other end of the branch diode D1, D2, D3 is connected to one end of a capacitor C1, the other end of the capacitor C1 is connected to one end of a shunt resistor R1, R2, R3 of each PFC branch and the rectifier bridge BG1 respectively, and the other end of the shunt resistor R1, R2, R3 of each PFC branch is connected to the source of the branch switching tube Q1, Q2, Q3.
When the collected current I1 is 3.5A, I2 is 6.5A, I3 is 8A, and the first threshold current Iref3 is 6, if the currents of the three branches are greater than the preset second threshold current, since I1 is less than Iref3, I2 is greater than Iref3, and I3 is greater than Iref3, it can be determined that the circuit failure fault of the first phase branch, and the number of the circuit branch failure faults is 1, so that the frequency-limited current of the compressor is reduced by 33.3%.
When the collected current I1 is 3.5A, I2 is 4.5A, I3 is 10A, and the first threshold current Iref3 is 6, since I1 is smaller than Iref3, I2 is smaller than Iref3, and I3 is larger than Iref3, it can be determined that the first and second phase branch circuits fail, and the number of the circuit branch failures is 2, so that the frequency-limited current of the compressor is reduced by 66.6%.
It will be understood by those skilled in the art that all or part of the flow of the method according to the above-described embodiment may be implemented by a computer program, which may be stored in a computer-readable storage medium and used to implement the steps of the above-described embodiments of the method when the computer program is executed by a processor. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying said computer program code, media, usb disk, removable hard disk, magnetic diskette, optical disk, computer memory, read-only memory, random access memory, electrical carrier wave signals, telecommunication signals, software distribution media, etc. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
Further, it should be understood that, since the modules are only configured to illustrate the functional units of the system of the present invention, the corresponding physical devices of the modules may be the processor itself, or a part of software, a part of hardware, or a part of a combination of software and hardware in the processor. Thus, the number of individual modules in the figures is merely illustrative.
Those skilled in the art will appreciate that the various modules in the system may be adaptively split or combined. Such splitting or combining of specific modules does not cause the technical solutions to deviate from the principle of the present invention, and therefore, the technical solutions after splitting or combining will fall within the protection scope of the present invention.
So far, the technical solution of the present invention has been described with reference to one embodiment shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
Claims (10)
1. A method for determining the failure of an interleaved PFC circuit is characterized in that,
connecting a plurality of PFC branches to an inverter from a rectifier bridge;
obtaining the current of a shunt resistor in each PFC branch in a plurality of PFC branches;
comparing the current of the shunt resistor in each PFC branch circuit with a first threshold current to judge whether one PFC branch circuit where the current is located has a fault;
and limiting the frequency of the compressor according to the judgment result.
2. The method according to claim 1, wherein the step of obtaining the current of the shunt resistor in each of the plurality of PFC branches specifically comprises:
collecting the currents of all PFC branches of the multi-path PFC branches, and judging whether the sum of the currents of all PFC branches is larger than or equal to a preset second threshold value;
if so, performing "comparing the current of the shunt resistor in each PFC branch with the first threshold current".
3. The method of claim 1,
"comparing the current of the shunt resistor in each PFC branch with a preset first threshold current to determine whether a PFC branch in which the current is located has a fault", specifically includes:
if one or more of the obtained currents of all the PFC branches are smaller than or equal to the first threshold current, and the currents of the other PFC branches are larger than the first threshold current, determining that one or more of the currents corresponding to one or more PFC branches have faults;
"according to the said judged result, carry on the frequency limitation to the compressor", include specifically:
and limiting the frequency of the compressor according to the number of the PFC branches with faults.
4. The method of any one of claims 2 or 3,
the first threshold current is a preset fixed current value;
alternatively, the first and second electrodes may be,
the first threshold current is a dynamic current value, and a calculation formula is as follows:
Irefn＝Kn×(I1+I2+...+In)
wherein, for a multi-path PFC circuit with n branches, IrefnIs a preset threshold current; knThe general value is 1/n; i isnThe collected current value of the shunt resistor R passing through the nth branch circuit is obtained;
the "limiting the frequency of the compressor according to the judgment result" specifically includes:
if m branches in the multi-path PFC circuits of the n branches have faults, the frequency limiting current value of the compressor is reduced by m/n.
5. A system for determining the failure of an interleaved PFC circuit is characterized in that,
the interleaved PFC circuit comprises a plurality of PFC branches connected to an inverter;
the acquisition module is used for acquiring the current of the shunt resistor in each PFC branch in the multiple PFC branches;
the judging module is used for comparing the current of the shunt resistor in each PFC branch circuit with a first threshold current so as to judge whether one PFC branch circuit where the current is located has a fault;
and the frequency limiting module is used for limiting the frequency of the compressor according to the judgment result.
6. The system of claim 5, wherein the acquisition module specifically performs the following operations:
collecting the currents of all PFC branches of the multi-path PFC branches, and judging whether the sum of the currents of all PFC branches is larger than or equal to a preset second threshold value;
if yes, entering a judging module to execute operation;
the judging module specifically executes the following operations:
if one or more of the obtained currents of all the PFC branches are smaller than or equal to the first threshold current, and the currents of the other PFC branches are larger than the first threshold current, determining that one or more of the currents corresponding to one or more PFC branches have faults;
the frequency limiting module specifically executes the following operations:
and limiting the frequency of the compressor according to the number of the PFC branches with faults.
7. The system of any one of claims 5 or 6,
the first threshold current is a preset fixed current value;
alternatively, the first and second electrodes may be,
the first threshold current is a dynamic current value, and a calculation formula is as follows:
Irefn＝Kn×(I1+I2+...+In)
wherein, for a multi-path PFC circuit with n branches, IrefnIs a preset threshold current; knThe general value is 1/n; i isnThe collected current value of the shunt resistor R passing through the nth branch circuit is obtained;
the frequency limiting module specifically further performs the following operations:
if m branches in the multi-path PFC circuits of the n branches have faults, the frequency limiting current value of the compressor is reduced by m/n.
8. The method of claim 1 or the system of claim 5,
the multi-path PFC branch specifically comprises: each PFC branch is connected to one end of a branch inductor from a rectifier bridge, the other end of the branch inductor L is respectively connected to one end of a branch diode D and a drain electrode of a branch switching tube Q, the other end of the branch diode D is connected to one end of a capacitor C1, the other end of the capacitor C1 is respectively connected to one end of a shunt resistor R of each PFC branch and the rectifier bridge, and the other end of the shunt resistor R of each PFC branch is connected to a source electrode of the branch switching tube Q; and the multi-path PFC branch is composed of at least two branches in parallel.
9. A computer-readable storage medium having stored therein a plurality of program codes adapted to be loaded and executed by a processor to perform the method for determining a failure in an interleaved PFC circuit according to any one of claims 1 to 4.
10. A processing apparatus comprising a processor and a memory, the memory device adapted to store a plurality of program codes, wherein the program codes are adapted to be loaded and run by the processor to perform the method of determining a failure in an interleaved PFC circuit according to any one of claims 1 to 4.
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