Method for controlling NPC three-level inverter fault redundancy

A three-level inverter and redundant control technology, which is applied to electrical components, AC power input conversion to DC power output, output power conversion devices, etc., can solve the problem of increased hardware costs and insufficient use of multi-level Inverter software control method redundancy characteristics, complex system structure and other issues, to achieve the effect of improving reliability

Active Publication Date: 2013-10-30
大庆富鹏节能技术开发有限公司
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

This method can achieve continuous and stable operation of the system, but the cost is that the structure of the system is more complicated, the hardware cost of the system increases, and the control method is also complicated
[0015] The above methods are based on the hardware and topology of the system to improve the operation reliability of the inverter, and do not make full use of the redundancy characteristics of the software control method of the multi-level inverter itself.

Method used

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  • Method for controlling NPC three-level inverter fault redundancy

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Embodiment 1

[0056] Embodiment 1: Real-time monitoring of device faults is performed on the NPC three-level inverter. When the device S is detected 11 When the terminal voltage is always zero, S 11 If a short-circuit fault occurs in the tube, if the phase A of the inverter is still output at the O level state, it will cause the capacitor C 1 short circuit, therefore, S 11 After a short-circuit fault occurs in the tube, the A phase can only output the two level states of P and N, and cannot output the O level state. Image 6 is the space voltage vector distribution diagram in the fault state, and the double dashed line in the figure is the fault loss vector. The vectors lost after phase A loses the O level state include zero vectors (OOO), small vectors (ONO, ONN, OON, OPO, OPP, OOP) and medium vectors (OPN, ONP). observe Image 6 It can be seen that both the lost zero vector and the small vector have redundant vectors, and the medium vectors lost in the second and fifth sectors have no...

Embodiment 2

[0060] Embodiment 2: Real-time monitoring of device faults is performed on NPC three-level inverters. When a device S is detected 11 When the terminal voltage of S is always non-zero, S 11 An open-circuit fault occurs in the tube, and at this time, the phase A of the inverter cannot output the P level state. Therefore, the S 11 After a short-circuit fault occurs in the tube, the A phase can only output two levels of O and N. Figure 7 It is the space voltage vector distribution diagram in the fault state, the double dashed line in the figure is the fault loss vector, the loss vector after the A phase loss P state includes zero vector (PPP), small vector (PPO, POO, POP) , medium vector (PON, PNO) and large vector (PPN, PNN, PNP). In the vector diagram, both the lost zero vector and the small vector have redundant vectors; in the first and sixth sectors, the lost medium vector has no redundant vectors; in the first, second, fifth, and sixth sectors, the lost large vector has n...

Embodiment 3

[0063] Embodiment 3: Real-time monitoring of device faults for NPC three-level inverters, when the device S is detected 12 When the terminal voltage of S is always zero, S 12 If a short-circuit fault occurs in the tube, if the A phase of the inverter is still output at the N level state, it will cause the capacitance C 2 short circuit, therefore, S 12 After a short-circuit fault occurs in the tube, the A phase can only output two level states of P and O, and cannot output the N level state. Figure 8 It is the space voltage vector distribution diagram in the fault state, the double dashed line in the figure is the fault loss vector, and the loss vector after the A phase loses the N state includes zero vector (NNN), small vector (NON, NOO, NNO) , medium vector (NPO, NOP) and large vector (NPN, NPP, NNP). In the vector diagram, both the lost zero vector and the small vector have redundant vectors; in the third and fourth sectors, the lost medium vector has no redundant vector...

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Abstract

The invention discloses a method for controlling NPC three-level inverter fault redundancy. The method for controlling the NPC three-level inverter fault redundancy comprises the following steps of (1) carrying out fault detection on an NPC three-level inverter in real time to confirm a fault position and a fault type, (2) confirming lost voltage vectors according to the fault position and the fault type, and drawing a vector diagram of fault states, (3) analyzing whether the inverter can continue to run or not under the fault states according to the redrawn vector diagram, (4) analyzing whether the inverter can run in an original level or not under the fault states according to the redrawn vector diagram, and (5) for the fault states under which the inverter can continue to run, reselecting resultant vectors, calculating the action time of all the resultant vectors, optimizing the switching sequence of the vectors, and forming a redundancy control impulse train. The method for controlling the NPC three-level inverter fault redundancy solves the problem of reliability of the three-level inverter based on a software method and effectively improves the reliability of the system on the basis that the cost of hardware of the system is not increased.

Description

technical field [0001] The invention relates to a fault redundant control method of an NPC three-level inverter. Background technique [0002] High-power conversion can be realized in many ways, and multilevel inverter has become a research hotspot in the field of high-power high-voltage conversion because of its series of advantages. The diode neutral point clamped (NPC) three-level inverter has become the focus of research on multi-level high-voltage and high-power inverters due to its relatively mature topology and control methods. Compared with the traditional two-level inverter topology, the advantages of the diode mid-point clamped three-level inverter mainly include: [0003] (1) The average forward blocking voltage borne by each main switching device is half of the bus voltage on the DC side; [0004] (2) It can greatly reduce harmonics, reduce switching frequency, and reduce system loss. If the same output performance index is to be measured and measured by switch...

Claims

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Application Information

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IPC IPC(8): H02M7/487
Inventor 马文忠
Owner 大庆富鹏节能技术开发有限公司
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