CN113098273B - Multi-input Boost circuit and fault detection method thereof - Google Patents

Multi-input Boost circuit and fault detection method thereof Download PDF

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CN113098273B
CN113098273B CN202110448022.4A CN202110448022A CN113098273B CN 113098273 B CN113098273 B CN 113098273B CN 202110448022 A CN202110448022 A CN 202110448022A CN 113098273 B CN113098273 B CN 113098273B
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symmetrical
circuit
group
boost circuit
symmetrical boost
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CN113098273A (en
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王航
王富
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Sungrow Power Supply Co Ltd
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Sungrow Power Supply Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
    • G01R31/2801—Testing of printed circuits, backplanes, motherboards, hybrid circuits or carriers for multichip packages [MCP]
    • G01R31/281—Specific types of tests or tests for a specific type of fault, e.g. thermal mapping, shorts testing
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The application discloses a multi-input boostt circuit and fault detection method thereof, in order to avoid the overvoltage breakdown of bus capacitor caused by the turn-off failure of upper tube or lower tube. The method comprises the following steps: judging absolute value |V of difference between positive bus capacitor voltage and negative bus capacitor voltage output by multi-input Boost circuit C1 ‑V C2 And if the I is larger than the first threshold, controlling each path of symmetrical Boost circuit to be directly connected and processing the subsequent circuit, wherein the processing is wave-sealing processing or disconnection of the subsequent circuit.

Description

Multi-input Boost circuit and fault detection method thereof
Technical Field
The invention relates to the technical field of power electronics, in particular to a multi-input Boost circuit and a fault detection method thereof.
Background
Fig. 1 shows a multiple-input Boost circuit comprising: and the input ends of the multiple paths of symmetrical Boost circuits are independently connected into the photovoltaic cell panel, and the output ends of the multiple paths of symmetrical Boost circuits are connected into the rear-stage circuit in parallel.
In the normal operation process of the multi-input Boost circuit, if the upper tube or the lower tube of one path of symmetrical Boost circuit has a turn-off failure (the turn-off failure can be caused by the damage of the switching tube, or the turn-off failure can be caused by the fact that the switching tube driving chip continuously provides high-level driving), the voltages of the positive bus capacitor and the negative bus capacitor (also called as the upper half bus capacitor and the lower half bus capacitor) output by the multi-input Boost circuit are seriously unbalanced, and the overvoltage breakdown of the bus capacitors is extremely easy to cause.
Disclosure of Invention
In view of the above, the present invention provides a multi-input Boost circuit and a fault detection method thereof, so as to avoid overvoltage breakdown of a bus capacitor caused by turn-off failure of an upper tube or a lower tube.
A method of fault detection for a multi-input Boost circuit, the multi-input Boost circuit comprising: the input ends of the multiple paths of symmetrical Boost circuits are independently connected into the photovoltaic cell panel, and the output ends of the multiple paths of symmetrical Boost circuits are connected into the rear-stage circuit in parallel; the method comprises the following steps:
acquiring positive bus capacitor voltage V output by multi-input Boost circuit C1 And negative bus capacitance voltage V C2 ；
Judging |V C1 -V C2 And if the I is larger than the first threshold, controlling all the symmetrical Boost circuits to be directly connected and processing the rear-stage circuit, wherein the processing is to seal the rear-stage circuit or disconnect the multi-input Boost circuit from the rear-stage circuit.
Optionally, after the controlling all symmetrical Boost circuits to pass through and processing the post-stage circuit, the method further includes: fault detection is carried out on each path of symmetrical Boost circuit one by one;
the fault detection of any path of symmetrical Boost circuit comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value, only the symmetrical Boost circuit is controlled to recover normal wave generation; if |V C1 -V C2 The I is increased to be larger than a second threshold value, and the existence of faults of the symmetrical Boost circuit of the circuit is judged; when the bus voltage rises to the second given value |V C1 -V C2 The I is not larger than the second threshold, and the symmetrical Boost circuit of the current path is judged to be fault-free; the second given value is greater than the first given value, and the second threshold value is greater than the first threshold value.
Optionally, when fault detection is performed on each path of symmetrical Boost circuit one by one, if no fault is detected on the previous N-1 path of symmetrical Boost circuit, directly judging that the N path of symmetrical Boost circuit has faults, and no fault detection is performed on the N path of symmetrical Boost circuit; n is the total number of symmetrical Boost circuits contained in the multi-input Boost circuit, and N is more than or equal to 2.
Or after the control of all the symmetrical Boost circuits is directly connected and the post-stage circuits are processed, the method further comprises the following steps: sequentially carrying out fault detection on each group of symmetrical Boost circuits by taking the group as a unit;
the fault detection of any group of symmetrical Boost circuits comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value, only controlling each path of symmetrical Boost circuit in the group to recover normal wave generation; if |V C1 -V C2 When the I is increased to be larger than a second threshold value, judging that at least one path of symmetrical Boost circuits in the group have faults, and if the group contains multiple paths of symmetrical Boost circuits, detecting faults of all paths of symmetrical Boost circuits in the group one by one; when the bus voltage rises to the second given value |V C1 -V C2 The I is not larger than the second threshold, and each path of symmetrical Boost circuit in the group is judged to be fault-free; the second given value is greater than the first given value, the second thresholdA value equal to or greater than the first threshold;
the fault detection of any path of symmetrical Boost circuit in the group comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to the first given value, only the symmetrical Boost circuit is controlled to recover normal wave generation; thereafter, if |V C1 -V C2 When the I is increased to be larger than the second threshold value, judging that the symmetrical Boost circuit of the current path has faults, and if the bus voltage is increased to the second given value, the I V is calculated C1 -V C2 And judging that the symmetrical Boost circuit of the current path has no fault when the I is not larger than the second threshold value.
Optionally, when fault detection is performed on each path of symmetrical Boost circuits in the group one by one, if no fault is detected by the first M-1 path of symmetrical Boost circuits in the group, directly judging that the M path of symmetrical Boost circuits have faults, and no fault detection is performed on the M path of symmetrical Boost circuits; m is the total number of symmetrical Boost circuits contained in the group, and M is more than or equal to 2.
Optionally, when the last group only includes one symmetrical Boost circuit, if no fault is detected in each previous group, it is directly determined that the last group of symmetrical Boost circuits has a fault, and no fault detection is required for the last group of symmetrical Boost circuits.
Optionally, after determining that any of the symmetrical Boost circuits has a fault, the method further includes:
for V C1 、V C2 Compared with the size, when V C1 >V C2 When the lower tube of the symmetrical Boost circuit is judged to have a turn-off failure, when V C1 <V C2 And when the upper tube of the symmetrical Boost circuit of the current path is judged to have a turn-off failure.
Optionally, the multi-input Boost circuit fault detection method is applied to an initial startup process or a normal operation process of the multi-input Boost circuit.
Optionally, the first threshold corresponding to the multi-input Boost circuit in the initial power-on process is greater than the first threshold corresponding to the multi-input Boost circuit in the normal operation process.
Optionally, after the detection of the faults of the symmetrical Boost circuits is completed, if the detection result is that at least one of the symmetrical Boost circuits is faulty, the faulty symmetrical Boost circuits are directly connected, and the rest symmetrical Boost circuits recover normal wave generation and release the processing on the later-stage circuits.
The multi-input Boost circuit comprises a main circuit and a control circuit, wherein the main circuit comprises a plurality of paths of symmetrical Boost circuits, the input ends of the paths of symmetrical Boost circuits are independently connected into a photovoltaic cell panel, and the output ends of the paths of symmetrical Boost circuits are connected into a rear-stage circuit in parallel;
the control circuit is used for acquiring positive bus capacitor voltage V output by the multi-input Boost circuit C1 And negative bus capacitance voltage V C2 The method comprises the steps of carrying out a first treatment on the surface of the Judging |V C1 -V C2 And if the I is larger than the first threshold, controlling all the symmetrical Boost circuits to be directly connected and processing the rear-stage circuit, wherein the processing is to seal the rear-stage circuit or disconnect the multi-input Boost circuit from the rear-stage circuit.
Optionally, after controlling all symmetrical Boost circuits to pass through and processing the post-stage circuit, the control circuit further includes: fault detection is carried out on each path of symmetrical Boost circuit one by one;
the fault detection of any path of symmetrical Boost circuit comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value, only the symmetrical Boost circuit is controlled to recover normal wave generation; if |V C1 -V C2 The I is increased to be larger than a second threshold value, and the existence of faults of the symmetrical Boost circuit of the circuit is judged; when the bus voltage rises to the second given value |V C1 -V C2 The I is not larger than the second threshold, and the symmetrical Boost circuit of the current path is judged to be fault-free; the second given value is greater than the first given value, and the second threshold value is greater than the first threshold value.
Optionally, when the control circuit detects faults of the symmetrical Boost circuits one by one, if no fault is detected by the N-1 th symmetrical Boost circuit, the control circuit directly judges that the N-th symmetrical Boost circuit has faults, and does not need to detect faults of the N-th symmetrical Boost circuit; n is the total number of symmetrical Boost circuits contained in the multi-input Boost circuit, and N is more than or equal to 2.
Or, after controlling all symmetrical Boost circuits to pass through and processing the post-stage circuit, the control circuit further comprises: sequentially carrying out fault detection on each group of symmetrical Boost circuits by taking the group as a unit;
the fault detection of any group of symmetrical Boost circuits comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value, only controlling each path of symmetrical Boost circuit in the group to recover normal wave generation; if |V C1 -V C2 When the I is increased to be larger than a second threshold value, judging that at least one path of symmetrical Boost circuits in the group have faults, and if the group contains multiple paths of symmetrical Boost circuits, detecting faults of all paths of symmetrical Boost circuits in the group one by one; when the bus voltage rises to the second given value |V C1 -V C2 The I is not larger than the second threshold, and each path of symmetrical Boost circuit in the group is judged to be fault-free; the second given value is larger than the first given value, and the second threshold value is larger than or equal to the first threshold value;
the fault detection of any path of symmetrical Boost circuit in the group comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to the first given value, only the symmetrical Boost circuit is controlled to recover normal wave generation; thereafter, if |V C1 -V C2 When the I is increased to be larger than the second threshold value, judging that the symmetrical Boost circuit of the current path has faults, and if the bus voltage is increased to the second given value, the I V is calculated C1 -V C2 And judging that the symmetrical Boost circuit of the current path has no fault when the I is not larger than the second threshold value.
Optionally, when the control circuit is configured to detect faults of the symmetrical Boost circuits in the group one by one, if no fault is detected by the previous M-1 symmetrical Boost circuit in the group, it is directly determined that the M-th symmetrical Boost circuit has faults, and no fault detection is required to be performed on the M-th symmetrical Boost circuit; m is the total number of symmetrical Boost circuits contained in the group, and M is more than or equal to 2.
Optionally, when the last group includes only one symmetrical Boost circuit, if no fault is detected in each previous group, the control circuit is configured to directly determine that the last group of symmetrical Boost circuits has a fault, and no fault detection is required to be performed on the last group of symmetrical Boost circuits.
Optionally, after determining that any of the symmetrical Boost circuits has a fault, the control circuit is further configured to perform a fault detection on the voltage C1 、V C2 Compared with the size, when V C1 >V C2 When the lower tube of the symmetrical Boost circuit is judged to have a turn-off failure, when V C1 <V C2 And when the upper tube of the symmetrical Boost circuit of the current path is judged to have a turn-off failure.
As can be seen from the technical scheme, the invention detects |V C1 -V C2 When the I exceeds a first threshold value, the multi-input Boost circuit is controlled to be directly connected and the post-stage circuit is processed, and the processing is to seal the wave or disconnect the multi-input Boost circuit from the post-stage circuit, so that overvoltage breakdown of a bus capacitor caused by shutdown failure of an upper pipe or a lower pipe of any one of the symmetrical Boost circuits is avoided.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a multi-input Boost circuit topology as disclosed in the prior art;
FIG. 2 is a flow chart of a method for detecting faults of a multi-input Boost circuit, disclosed by the embodiment of the invention;
FIG. 3 is a schematic diagram of a corresponding current-exchanging path when upper and lower tubes of the 1 st path of symmetrical Boost circuit are simultaneously opened;
FIG. 4 is a schematic diagram of a corresponding commutation path when the upper tube of the 1 st path symmetrical Boost circuit is turned off and the lower tube is turned on;
fig. 5 is a schematic diagram of yet another multiple input Boost circuit topology.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 2, an embodiment of the present invention discloses a method for detecting a fault of a multi-input Boost circuit, where the fault refers to a shutdown failure of an upper pipe or a lower pipe of at least one path of symmetrical Boost circuit in the multi-input Boost circuit, and the method for detecting a fault of the multi-input Boost circuit includes:
step S01: acquiring positive bus capacitor voltage V output by multi-input Boost circuit C1 And negative bus capacitance voltage V C2 。
Step S02: judging |V C1 -V C2 If yes, the step S03 is started, and if no, the step S01 is returned.
Specifically, when the upper tube or the lower tube of one of the symmetrical Boost circuits of the multi-input Boost circuit has turn-off failure, the voltages of the positive bus capacitor and the negative bus capacitor of the later circuit are seriously unbalanced, so that the serious unbalance of the voltages of the positive bus capacitor and the negative bus capacitor of the later circuit can be used as a basis for checking whether the upper tube or the lower tube of the one of the symmetrical Boost circuits of the multi-input Boost circuit has turn-off failure. Of course, since the faults of the back-stage circuit of the multi-input Boost circuit can also cause serious unbalance of the voltages of the positive bus capacitor and the negative bus capacitor of the back-stage circuit, the embodiment of the invention is performed under the condition that the back-stage circuit has no faults by default.
The topology of the multi-input Boost circuit is described in the background section. Under the condition that the default post-stage circuit has no faults, the topology structure and the current-exchanging path of the symmetrical Boost circuit are combined to explain why the upper pipe or the lower pipe of one path of symmetrical Boost circuit of the multi-input Boost circuit has a turn-off failure, and the positive bus capacitance voltage and the negative bus capacitance voltage of the post-stage circuit are seriously unbalanced.
Still referring to fig. 1, the constituent elements of the i-th (i=1, 2, …, N is the total number of symmetrical Boost circuits included in the multi-input Boost circuit) symmetrical Boost circuit include an inductor l1_i, an inductor l2_i, an upper tube q1_i, a lower tube q2_i, a freewheeling diode d3_i, a freewheeling diode d4_i, and a positive bus capacitor C1 and a negative bus capacitor C2 shared by the symmetrical Boost circuits, and the connection relationships between the constituent elements are:
the input end of the upper tube Q1_i is connected with one end of an inductor L1_i and the anode of a freewheel diode D3_i, the other end of the inductor L1_i is an input positive pole PVi+ of an ith path symmetrical Boost circuit, and the cathode of the freewheel diode D3_i is connected with the positive pole of a positive BUS capacitor C1, namely a positive BUS BUS+ of a later-stage circuit;
the output end of the upper tube Q1_i is connected with the input end of the lower tube Q2_i, the negative electrode of the positive bus capacitor C1 and the positive electrode of the negative bus capacitor C2;
the output end of the lower tube Q2_i is connected with one end of an inductor L2_i and the cathode of a freewheel diode D4_i, the other end of the inductor L2_i is an input cathode PVi-of an ith path of symmetrical Boost circuit, and the anode of the freewheel diode D4_i is connected with the cathode of a negative BUS capacitor C2, namely a negative BUS BUS-of a later-stage circuit.
The working principle of the symmetrical Boost circuits is the same, and the 1 st symmetrical Boost circuit is taken as an example: the 1 st path symmetrical Boost circuit realizes Boost by switching the switch states of the upper tube and the lower tube during normal operation, the upper tube Q1_1 and the lower tube Q2_1 can be always connected with the same switch or be always complementarily conducted, and the positive bus capacitor voltage V C1 And negative bus capacitor voltage V C2 Equal or approximately equal (V C1 +V C2 Equal to the bus voltage). However, if the upper tube q1_1 is normal and the lower tube q2_1 is turned off, the switch combination state of the upper tube q1_1 and the lower tube q2_1 is only switched between two switch combination states, one is that the upper tube q1_1 and the lower tube q2_1 are simultaneously turned onOn, one is that the upper tube q1_1 is turned off and the lower tube q2_1 is turned on; when the upper tube q1_1 and the lower tube q2_1 are simultaneously opened, the corresponding commutation paths are shown in fig. 3, and are the Pv1+ →l1_1→q1_1→q2_1→l2_1→pv1-, at this time, the inductors l1_1 and l2_1 are charged and store energy, and the busbar capacitors C1 and C2 provide energy for the later-stage circuits; when the upper tube Q1_1 is turned off and the lower tube Q2_1 is turned on, the corresponding commutation path is Pv1+ & fwdarw.L1_1→d3_1→C1→Q2_1→L2_1→Pv1-, as shown in FIG. 4, the positive bus capacitor C1 is continuously charged, V C1 The increasing voltage eventually causes an overvoltage breakdown of the positive bus capacitor C1. Similarly, if the lower tube Q1_2 is normal and the upper tube Q2_1 is in the off failure, V C2 Will increase continuously, eventually leading to overvoltage breakdown of the negative bus capacitor C2.
Similarly, when the lower tubes of two, three or more paths of symmetrical Boost circuits in the multi-input Boost circuit are normal and the upper tubes are in turn-off failure, the overvoltage breakdown of the negative bus capacitor C2 is also caused; when the upper tubes of two paths, three paths or more paths of symmetrical Boost circuits in the multi-input Boost circuit are normal and the lower tubes are in turn-off failure, overvoltage breakdown of a positive bus capacitor C1 is caused; when the lower tube of one path of symmetrical Boost circuit is normal and the upper tube is in turn-off failure, the upper tubes of the other two paths of symmetrical Boost circuits are normal and the lower tube is in turn-off failure, the upper tubes and the lower tubes of the rest N-3 paths of symmetrical Boost circuits are normal, and overvoltage breakdown of a positive bus capacitor C1 is caused; … …, the various cases are not listed one by one. In summary, as long as |V is detected C1 -V C2 And if the I is larger than the first threshold value, the condition that the upper pipe or the lower pipe in at least one path of Boost circuit is in turn-off failure is indicated.
Wherein, when the value of the first threshold is set, if the value of the first threshold is too large, |V C1 -V C2 When the voltage resistance value of the bus capacitor is certain, the larger the bus voltage is, the smaller the value of the first threshold value is preferably set, so that the fault detection is triggered as early as possible; however, if the first threshold is too small, it is also possible that the value of |V C1 -V C2 Small amplitude jitter to occur "at leastThe upper pipe or the lower pipe in one Boost circuit has misjudgment of shutdown failure, so that the value of the first threshold value needs to comprehensively consider the two conditions.
For example, it is known that a multi-input Boost circuit has an initial power-on process and a normal operation process, and a bus voltage output in the initial power-on process of the multi-input Boost circuit is lower than a bus voltage output in the normal operation process, and the multi-input Boost circuit fault detection method can be applied to the initial power-on process or the normal operation process of the multi-input Boost circuit. Assuming that the withstand voltage value of the bus capacitor is 700V, the bus voltage output in the normal operation process of the multi-input Boost circuit is 1160V, and the bus voltage output in the initial startup process is lower than 900V, the first threshold value can be set to be equal to 100V when the multi-input Boost circuit is applied in the normal operation process of the multi-input Boost circuit, and the first threshold value can be set to be equal to 300V when the multi-input Boost circuit is applied in the initial startup process of the multi-input Boost circuit. Of course, in order to simplify the parameter setting process, the corresponding first threshold values in the initial startup process and the normal operation process of the multi-input Boost circuit may be set to the same value, for example, all set to 100V.
Optionally, the ith symmetric Boost circuit disclosed above further includes: the bypass diode d5_i and/or the bypass diode d6_i are/is shown in fig. 5, for example, the anode of the bypass diode d5_i is connected with the input positive electrode pvi+ of the ith path symmetrical Boost circuit, the cathode is connected with the positive electrode of the positive bus capacitor C1, and the cathode of the bypass diode d6_i is connected with the input negative electrode PVi of the ith path symmetrical Boost circuit, and the anode is connected with the negative electrode of the negative bus capacitor C2. The bypass diode only plays a role of bypass protection and does not affect the commutation path of the symmetrical Boost circuit, so the analysis of the symmetrical Boost circuit shown in fig. 1 is applicable to the symmetrical Boost circuit shown in fig. 5.
Step S03: all symmetrical Boost circuits in the multi-input Boost circuit are controlled to pass through and process the subsequent stage circuits.
Specifically, the symmetrical Boost circuit is through, that is, the direct current input of the symmetrical Boost circuit is short-circuited. It should be noted that, because the photovoltaic cell panel is soft, the output current is limited, so the device overcurrent damage can not be caused when the direct current input of the symmetrical Boost circuit is short-circuited. The processing performed on the post-stage circuit is to perform wave sealing on the post-stage circuit or disconnect the multi-input Boost circuit from the post-stage circuit, and in general, when the post-stage circuit is an inverter circuit or a DC/DC circuit, the processing is to perform wave sealing on the inverter circuit or the DC/DC circuit, and when the post-stage circuit is an energy storage battery, the processing is to disconnect the multi-input Boost circuit from the energy storage battery.
After all symmetrical Boost circuits in the multi-input Boost circuit are controlled to be directly connected and the post-stage circuit is processed, for the integral structure formed by the multi-input Boost circuit and the post-stage circuit, only an auxiliary power supply works in the integral structure to supply power for a control system and a driving circuit in the integral structure, and at the moment, the energy on a bus capacitor of the post-stage circuit is released through the auxiliary power supply, and the bus voltage starts to drop. Therefore, overvoltage breakdown of the bus capacitor caused by the shutdown failure of the upper pipe or the lower pipe is avoided.
In addition, considering that only the symmetrical Boost circuit with the upper pipe or lower pipe turn-off failure is accurately positioned, the problem can be efficiently and pointedly solved, and the fault checking time is saved. Therefore, after the step S03, the embodiment of the present invention further includes: and detecting faults of the symmetrical Boost circuits one by one, so that whether the upper pipe or the lower pipe of the symmetrical Boost circuit is in turn-off failure is positioned.
The fault detection of any path of symmetrical Boost circuit comprises the following steps:
after all symmetrical Boost circuits in the multi-input Boost circuit are controlled to be directly connected and the subsequent-stage circuit is processed, when the bus voltage is reduced to a first given value Vbus1, only the symmetrical Boost circuit of the current circuit is controlled to restore normal wave generation, the rest symmetrical Boost circuits still remain to be directly connected and the subsequent-stage circuit still maintains the processing; thereafter, if |V C1 -V C2 Further expansion, for example to a value greater than a second threshold value (the second threshold value is greater than the first threshold value, for example second threshold value=first threshold value+50v), the existence of faults in the own-path symmetrical Boost circuit can be directly determined, if the bus voltage rises to a second given value Vbus2, the value of |v C1 -V C2 The I is not increased to be larger than the second threshold value, and the symmetrical Boost circuit of the current path is considered to be fault-free; vbus1 < Vbus2.
For example, assuming that the withstand voltage of the bus capacitor is 700V, the bus voltage output during the normal operation of the multi-input Boost circuit is 1160V, and the bus voltage output during the initial start-up of the multi-input Boost circuit is lower than 900V, the multi-input Boost circuit fault detection method may be used to set, for example, the first given value Vbus1 to be 900V and the second given value Vbus2 to be 1160V when the multi-input Boost circuit is in normal operation, and may be used to set, for example, the first given value Vbus1 to be 600V and the second given value Vbus2 to be 900V when the multi-input Boost circuit is in initial start-up.
Optionally, when fault detection is performed on each path of symmetrical Boost circuit one by one, if no fault is detected on the previous N-1 path of symmetrical Boost circuit, the existence of faults of the Nth path of symmetrical Boost circuit can be directly judged, and the fault detection is not required to be performed on the Nth path of symmetrical Boost circuit; if at least one of the N-1 paths of symmetrical Boost circuits has faults, the N paths of symmetrical Boost circuits need to be continuously subjected to fault detection.
From the above description, it can be seen that the embodiment of the present invention detects |V C1 -V C2 When the I exceeds a first threshold value, the multi-input Boost circuit is controlled to be directly connected and processed (the processing is that the wave is sealed to the post-stage circuit or the connection between the multi-input Boost circuit and the post-stage circuit is disconnected), and then the wave generation of each path of symmetrical Boost circuit is recovered one by one and combined with the I V C1 -V C2 Whether or not is further increased to locate which way of symmetrical Boost circuit the fault belongs to.
After the detection is finished, if the detection result is that at least one path of symmetrical Boost circuit has a fault, the fault symmetrical Boost circuit can be directly communicated, the rest symmetrical Boost circuits recover normal wave generation and the post-stage circuit release the processing, at the moment, the multi-input Boost circuit recovers power generation, and maintenance is performed by maintenance staff until other proper time (for example, when photovoltaic does not generate power at night), and the embodiment of the invention is taken as a recommended processing measure; in addition, after the detection is completed, if the detection result is that at least one path of symmetrical Boost circuit fails, the multi-input Boost circuit can be kept in a through state and the post-stage circuit keeps the processing, and maintenance personnel can be immediately notified to maintain. The fault detection result can be directly displayed locally or reported to the monitoring room.
Alternatively, after the step S03, the embodiment of the present invention further includes: and sequentially carrying out fault detection on each group of symmetrical Boost circuits by taking the group as a unit. By means of packet detection, detection efficiency is improved.
The fault detection of any group of symmetrical Boost circuits comprises the following steps: after all symmetrical Boost circuits in the multi-input Boost circuit are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value Vbus1, only controlling each symmetrical Boost circuit in the group to restore normal wave generation, wherein the rest symmetrical Boost circuits still remain to be directly connected and the post-stage circuit still maintains the processing; thereafter, if |V C1 -V C2 When the I is increased to be larger than a second threshold value, judging that at least one path of symmetrical Boost circuits in the group have faults, and if the group contains multiple paths of symmetrical Boost circuits, detecting faults of all paths of symmetrical Boost circuits in the group one by one; when the bus voltage rises to a second set value Vbus2 |V C1 -V C2 The I is not larger than the second threshold, and each path of symmetrical Boost circuit in the group is judged to be fault-free; vbus1 < Vbus2; the second threshold value is greater than or equal to the first threshold value.
Performing fault detection on any one of the symmetrical Boost circuits in the group, including: after all symmetrical Boost circuits in the multi-input Boost circuit are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value Vbus1, only the symmetrical Boost circuit in the multi-input Boost circuit is controlled to restore normal wave generation, the rest symmetrical Boost circuits in the multi-input Boost circuit still remain to be directly connected and the post-stage circuit all keeps processing; if |V C1 -V C2 When the I is increased to be larger than a second threshold value, judging that the symmetrical Boost circuit of the current path has faults, and if the bus voltage is increased to a second given value Vbus2, the I V is calculated C1 -V C2 And judging that the symmetrical Boost circuit of the current path has no fault when the I is not larger than the second threshold value.When it is determined that at least one path of symmetrical Boost circuit in the group has faults, if the group only comprises one path of symmetrical Boost circuit, the only path of symmetrical Boost circuit in the group has faults.
Optionally, when fault detection is performed on each path of symmetrical Boost circuits in the group one by one, if no fault is detected by the first M-1 path of symmetrical Boost circuits in the group, directly judging that the M path of symmetrical Boost circuits have faults, and no fault detection is performed on the M path of symmetrical Boost circuits; if at least one of the M-1 paths of symmetrical Boost circuits in the group has faults, the fault detection of the M-th path of symmetrical Boost circuit is needed to be continued; m is the total number of symmetrical Boost circuits contained in the group, and M is more than or equal to 2.
Optionally, in any of the above-disclosed packet detection embodiments, when the last group includes only one path of symmetrical Boost circuits, if no fault is detected in each previous group, directly determining that the last group of symmetrical Boost circuits has a fault, and no fault detection is required to be performed on the last group of symmetrical Boost circuits; if at least one of the previous groups has faults, continuing to perform fault detection on the symmetrical Boost circuit of the last group.
Optionally, in any of the embodiments disclosed above, in the fault detection process for any of the symmetrical Boost circuits, when it is determined that the symmetrical Boost circuit has a fault, the fault is detected by comparing the voltage value of the current circuit with the voltage value of the current circuit C1 、V C2 Comparing the sizes, it can further determine whether the upper tube or the lower tube of the symmetrical Boost circuit has a turn-off failure, when V C1 >V C2 When the lower tube of the symmetrical Boost circuit is judged to have a turn-off failure, when V C1 <V C2 And when the upper tube of the symmetrical Boost circuit of the current path is judged to have a turn-off failure.
Optionally, in any one of the embodiments disclosed above, the method for detecting a fault of the multi-input Boost circuit is applied to an initial startup process or a normal operation process of the multi-input Boost circuit; the values of the first threshold value, the second threshold value, the first given value and the second given value are reasonably set according to whether the multi-input Boost circuit is in an initial starting process or a normal operation process. And the application recommends that the first threshold value corresponding to the multi-input Boost circuit in the initial starting process is larger than the first threshold value corresponding to the multi-input Boost circuit in the normal operation process.
Corresponding to the embodiment of the method, the embodiment of the invention also discloses a multi-input Boost circuit, which comprises a main circuit and a control circuit; the main circuit comprises multiple paths of symmetrical Boost circuits, wherein the input ends of the symmetrical Boost circuits are independently connected with a photovoltaic panel, and the output ends of the symmetrical Boost circuits are connected with a later-stage circuit in parallel;
the control circuit is used for acquiring positive bus capacitor voltage V output by the multi-input Boost circuit C1 And negative bus capacitance voltage V C2 The method comprises the steps of carrying out a first treatment on the surface of the Judging |V C1 -V C2 And if the I is larger than the first threshold, controlling all the symmetrical Boost circuits to be directly connected and processing the rear-stage circuit, wherein the processing is to seal the rear-stage circuit or disconnect the multi-input Boost circuit from the rear-stage circuit.
Optionally, after the controlling all symmetrical Boost circuits to pass through and the processing is performed on the post-stage circuit, the method further includes: fault detection is carried out on each path of symmetrical Boost circuit one by one;
the fault detection of any path of symmetrical Boost circuit comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value, only the symmetrical Boost circuit is controlled to recover normal wave generation; if |V C1 -V C2 The I is increased to be larger than a second threshold value, and the existence of faults of the symmetrical Boost circuit of the circuit is judged; when the bus voltage rises to the second given value |V C1 -V C2 The I is not larger than the second threshold, and the symmetrical Boost circuit of the current path is judged to be fault-free; the second given value is greater than the first given value, and the second threshold value is greater than the first threshold value.
Optionally, when the control circuit detects faults of the symmetrical Boost circuits one by one, if no fault is detected by the N-1 th symmetrical Boost circuit, the control circuit directly judges that the N-th symmetrical Boost circuit has faults, and does not need to detect faults of the N-th symmetrical Boost circuit; n is the total number of symmetrical Boost circuits contained in the multi-input Boost circuit, and N is more than or equal to 2.
Or after the control of all the symmetrical Boost circuits is directly connected and the processing is performed on the post-stage circuit, the method further comprises the following steps: sequentially carrying out fault detection on each group of symmetrical Boost circuits by taking the group as a unit;
the fault detection of any group of symmetrical Boost circuits comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value, only controlling each path of symmetrical Boost circuit in the group to recover normal wave generation; if |V C1 -V C2 When the I is increased to be larger than a second threshold value, judging that at least one path of symmetrical Boost circuits in the group have faults, and if the group contains multiple paths of symmetrical Boost circuits, detecting faults of all paths of symmetrical Boost circuits in the group one by one; when the bus voltage rises to the second given value |V C1 -V C2 The I is not larger than the second threshold, and each path of symmetrical Boost circuit in the group is judged to be fault-free; the second given value is larger than the first given value, and the second threshold value is larger than or equal to the first threshold value;
the fault detection of any path of symmetrical Boost circuit in the group comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to the first given value, only the symmetrical Boost circuit is controlled to recover normal wave generation; thereafter, if |V C1 -V C2 When the I is increased to be larger than the second threshold value, judging that the symmetrical Boost circuit of the current path has faults, and if the bus voltage is increased to the second given value, the I V is calculated C1 -V C2 And judging that the symmetrical Boost circuit of the current path has no fault when the I is not larger than the second threshold value.
Optionally, when the control circuit is configured to detect faults of the symmetrical Boost circuits in the group one by one, if no fault is detected by the previous M-1 symmetrical Boost circuit in the group, it is directly determined that the M-th symmetrical Boost circuit has faults, and no fault detection is required to be performed on the M-th symmetrical Boost circuit; m is the total number of symmetrical Boost circuits contained in the group, and M is more than or equal to 2.
Optionally, when the last group includes only one symmetrical Boost circuit, if no fault is detected in each previous group, the control circuit is configured to directly determine that the last group of symmetrical Boost circuits has a fault, and no fault detection is required to be performed on the last group of symmetrical Boost circuits.
Optionally, in any of the multiple-input Boost circuits disclosed above, after determining that any of the symmetrical Boost circuits has a fault, the control circuit is further configured to perform a logic operation on the input voltage signal C1 、V C2 Compared with the size, when V C1 >V C2 When the lower tube of the symmetrical Boost circuit is judged to have a turn-off failure, when V C1 <V C2 And when the upper tube of the symmetrical Boost circuit of the current path is judged to have a turn-off failure.
Optionally, in any of the above disclosed multiple-input Boost circuits, the control circuit starts operation during an initial start-up process or during a normal operation process of the multiple-input Boost circuit.
Optionally, the first threshold corresponding to the multi-input Boost circuit in the initial power-on process is greater than the first threshold corresponding to the multi-input Boost circuit in the normal operation process.
Optionally, in any of the multiple-input Boost circuits disclosed in the foregoing disclosure, the control circuit is further configured to, after the detection of the faults of each path of the symmetrical Boost circuit is completed, if the detection result is that at least one path of the symmetrical Boost circuit has a fault, make the faulty symmetrical Boost circuit pass through, restore normal wave generation of the remaining symmetrical Boost circuits, and cancel the processing of the subsequent circuit, where the multiple-input Boost circuit resumes power generation.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the multi-input Boost circuit disclosed in the embodiment, the description is relatively simple because the multi-input Boost circuit corresponds to the method disclosed in the embodiment, and the relevant parts refer to the description of the method.
The terms first, second and the like in the description and in the claims and in the above-described figures, are used for distinguishing between similar different objects and not necessarily for describing a particular sequential or chronological order. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the embodiments of the invention. Thus, the present embodiments are not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (13)

1. A method for detecting a fault in a multi-input Boost circuit, the multi-input Boost circuit comprising: the input ends of the multiple paths of symmetrical Boost circuits are independently connected into the photovoltaic cell panel, and the output ends of the multiple paths of symmetrical Boost circuits are connected into the rear-stage circuit in parallel; the multi-path symmetrical Boost circuit shares a positive bus capacitor C1 and a negative bus capacitor C2; the method comprises the following steps:
acquiring positive bus capacitor voltage V output by multi-input Boost circuit C1 And negative bus capacitance voltage V C2 ；
Judging |V C1 -V C2 If the I is larger than a first threshold value, controlling all the symmetrical Boost circuits to be directly connected and processing the rear-stage circuit, wherein the processing is to seal waves on the rear-stage circuit or disconnect the multi-input Boost circuit from the rear-stage circuit; the symmetrical Boost circuit is connected throughThe direct current input of the symmetrical Boost circuit is short-circuited; the first threshold is a threshold set according to bus voltage, and the larger the bus voltage is, the smaller the first threshold is;
sequentially carrying out fault detection on each group of symmetrical Boost circuits by taking the group as a unit;
the fault detection for each group of symmetrical Boost circuits comprises the following steps: only controlling each path of symmetrical Boost circuits in the group to recover normal wave generation, and judging whether the symmetrical Boost circuits in the group have faults or not based on |VC1-VC 2|; if the symmetrical Boost circuits in the group are judged to have faults, then fault detection is carried out on the symmetrical Boost circuits in the group one by one;
the fault detection of any one of the symmetrical Boost circuits in the group comprises the following steps: and only controlling the symmetrical Boost circuit to recover the echo, and judging whether the symmetrical Boost circuit has faults or not based on the |VC1-VC 2|.
2. The method for detecting a fault in a multi-input Boost circuit according to claim 1, wherein the control-only symmetric Boost circuits in the group recover normal ripple and are based on |v C1 -V C2 The I judges whether the symmetric Boost circuit of the group has faults or not, and comprises the following steps: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value, only controlling each path of symmetrical Boost circuit in the group to recover normal wave generation; if |V C1 -V C2 When the I is increased to be larger than a second threshold value, judging that at least one path of symmetrical Boost circuits in the group have faults, and if the group contains multiple paths of symmetrical Boost circuits, detecting faults of all paths of symmetrical Boost circuits in the group one by one; when the bus voltage rises to the second given value |V C1 -V C2 The I is not larger than the second threshold, and each path of symmetrical Boost circuit in the group is judged to be fault-free; the second given value is larger than the first given value, and the second threshold value is larger than or equal to the first threshold value;
the control-only symmetric Boost circuit recovers the echo and is based on |v C1 -V C2 The I judges whether the symmetric Boost circuit of the current path has faults or not, and comprises the following steps: at a control stationAfter the symmetrical Boost circuit is directly connected and the post-stage circuit is processed, when the bus voltage is reduced to the first given value, only the symmetrical Boost circuit is controlled to recover normal wave generation; thereafter, if |V C1 -V C2 When the I is increased to be larger than the second threshold value, judging that the symmetrical Boost circuit of the current path has faults, and if the bus voltage is increased to the second given value, the I V is calculated C1 -V C2 And judging that the symmetrical Boost circuit of the current path has no fault when the I is not larger than the second threshold value.
3. The method for detecting the faults of the multi-input Boost circuit according to claim 2, wherein when the faults of the symmetrical Boost circuits in the group are detected one by one, if no faults are detected by the first M-1 symmetrical Boost circuits in the group, the faults of the M symmetrical Boost circuits are directly judged, and the faults of the M symmetrical Boost circuits are not detected; m is the total number of symmetrical Boost circuits contained in the group, and M is more than or equal to 2.
4. The method of claim 3, wherein when the last group includes only one symmetrical Boost circuit, if no fault is detected in each previous group, directly determining that the last group of symmetrical Boost circuits has a fault, without performing fault detection on the last group of symmetrical Boost circuits.
5. The method for detecting a fault in a multiple-input Boost circuit according to any one of claims 1 to 4, further comprising, after determining that any one of the symmetrical Boost circuits has a fault:
for V C1 、V C2 Compared with the size, when V C1 >V C2 When the lower tube of the symmetrical Boost circuit is judged to have a turn-off failure, when V C1 <V C2 And when the upper tube of the symmetrical Boost circuit of the current path is judged to have a turn-off failure.
6. The method for detecting a fault in a multi-input Boost circuit according to any one of claims 1 to 4, wherein the method for detecting a fault in a multi-input Boost circuit is applied to an initial start-up process or a normal operation process of the multi-input Boost circuit.
7. The method of claim 6, wherein the first threshold corresponding to the multi-input Boost circuit during an initial power-on process is greater than the first threshold corresponding to the multi-input Boost circuit during normal operation.
8. The method for detecting multiple input Boost circuit faults according to any one of claims 1 to 4, wherein after the detection of each path of symmetrical Boost circuit fault is completed, if the detection result is that at least one path of symmetrical Boost circuit fault, the faulty symmetrical Boost circuit is directly connected, and the rest symmetrical Boost circuits resume normal wave generation and the processing is released for the subsequent circuit.
9. A multi-input Boost circuit comprises a main circuit and a control circuit, and is characterized in that: the main circuit comprises multiple paths of symmetrical Boost circuits, wherein the input ends of the symmetrical Boost circuits are independently connected with a photovoltaic panel, and the output ends of the symmetrical Boost circuits are connected with a later-stage circuit in parallel; the multi-path symmetrical Boost circuit shares a positive bus capacitor C1 and a negative bus capacitor C2;
the control circuit is used for acquiring positive bus capacitor voltage V output by the multi-input Boost circuit C1 And negative bus capacitance voltage V C2 The method comprises the steps of carrying out a first treatment on the surface of the Judging |V C1 -V C2 If the I is larger than a first threshold value, controlling all the symmetrical Boost circuits to be directly connected and processing the rear-stage circuit, wherein the processing is to seal waves on the rear-stage circuit or disconnect the multi-input Boost circuit from the rear-stage circuit; the direct-pass of the symmetrical Boost circuit is to short-circuit the direct-current input of the symmetrical Boost circuit; the first threshold is a threshold set according to bus voltage, and the larger the bus voltage is, the smaller the first threshold is;
the control circuit is also used for sequentially carrying out fault detection on each group of symmetrical Boost circuits by taking the group as a unit;
the fault detection for each group of symmetrical Boost circuits comprises the following steps: only controlling each path of symmetrical Boost circuits in the group to recover normal wave generation, and judging whether the symmetrical Boost circuits in the group have faults or not based on |VC1-VC 2|; if the symmetrical Boost circuits in the group are judged to have faults, then fault detection is carried out on the symmetrical Boost circuits in the group one by one;
the fault detection of any one of the symmetrical Boost circuits in the group comprises the following steps: and only controlling the symmetrical Boost circuit to recover the echo, and judging whether the symmetrical Boost circuit has faults or not based on the |VC1-VC 2|.
10. The multi-input Boost circuit of claim 9, wherein controlling only the symmetric Boost circuits in the group to resume normal ripple and determining whether there is a fault in the symmetric Boost circuits in the group based on |vc1-vc2|, comprises: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to a first given value, only controlling each path of symmetrical Boost circuit in the group to recover normal wave generation; if |V C1 -V C2 When the I is increased to be larger than a second threshold value, judging that at least one path of symmetrical Boost circuits in the group have faults, and if the group contains multiple paths of symmetrical Boost circuits, detecting faults of all paths of symmetrical Boost circuits in the group one by one; when the bus voltage rises to the second given value |V C1 -V C2 The I is not larger than the second threshold, and each path of symmetrical Boost circuit in the group is judged to be fault-free; the second given value is larger than the first given value, and the second threshold value is larger than or equal to the first threshold value;
then performing fault detection on any one of the symmetrical Boost circuits in the group includes: only control this way symmetry Boost circuit resumes the ripple to judge whether this way symmetry Boost circuit has the trouble based on |VC1-VC2|, include: after all symmetrical Boost circuits are controlled to be directly connected and the post-stage circuit is processed, when the bus voltage is reduced to the first given value, only the symmetrical Boost circuit is controlled to recover normal wave generation; thereafter, if |V C1 -V C2 And I is increased to be larger than the second threshold value, and the existence of the symmetrical Boost circuit of the current path is judgedIn the event of a fault, if the busbar voltage rises to the second setpoint value, |V C1 -V C2 And judging that the symmetrical Boost circuit of the current path has no fault when the I is not larger than the second threshold value.
11. The multi-input Boost circuit of claim 10, wherein the control circuit is configured to directly determine that the M-th symmetric Boost circuit has a fault if none of the M-1 th symmetric Boost circuits in the group detects a fault when performing fault detection on each of the symmetric Boost circuits in the group one by one, without performing fault detection on the M-th symmetric Boost circuit; m is the total number of symmetrical Boost circuits contained in the group, and M is more than or equal to 2.
12. The multi-input Boost circuit of claim 11, wherein the control circuit is configured to directly determine that the last set of symmetrical Boost circuits has a fault if none of the previous sets has detected a fault when the last set only includes one symmetrical Boost circuit, without further fault detection of the last set of symmetrical Boost circuits.
13. The multiple-input Boost circuit of any one of claims 9-12, wherein the control circuit is further configured to provide a feedback signal to the control circuit after determining that any one of the symmetrical Boost circuits has failed C1 、V C2 Compared with the size, when V C1 >V C2 When the lower tube of the symmetrical Boost circuit is judged to have a turn-off failure, when V C1 <V C2 And when the upper tube of the symmetrical Boost circuit of the current path is judged to have a turn-off failure.
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