Fault-tolerant control method and system based on zero-sequence circulating current suppression

A zero-sequence circulating current and fault-tolerant control technology, which is applied in the direction of output power conversion device, AC power input conversion to DC power output, electrical components, etc., can solve the difficulty of zero-sequence circulating current suppression, and can not realize zero-sequence circulating current suppression of parallel system at the same time and fault tolerance control, reducing the modulation ratio, etc., to achieve the effects of low cost, reduced switch stress, and improved power quality

Pending Publication Date: 2022-01-04
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the HB switch tube fails, in order to use the normal voltage vector synthesis to output the reference voltage, the inverter system must reduce the modulation ratio to operate, so the amplitude of the system output voltage will also decrease accordingly. Obviously, this is in the grid-connected type Inverter is not allowed
In addition, since the system has no redundant voltage vectors to choose from at this time, it becomes very difficult to suppress the zero-sequence circulating current of the parallel system from the perspective of modulation or control; at the same time, the existing technology cannot simultaneously realize the zero-sequence circulating current of the parallel system Inhibition and Fault Tolerant Control

Method used

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  • Fault-tolerant control method and system based on zero-sequence circulating current suppression
  • Fault-tolerant control method and system based on zero-sequence circulating current suppression
  • Fault-tolerant control method and system based on zero-sequence circulating current suppression

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Embodiment 1

[0037] Such as figure 1 As shown, Embodiment 1 of the present disclosure provides a fault-tolerant control method based on zero-sequence circulating current suppression, which includes the following three basic steps:

[0038] S1: Zero-sequence circulating current suppression

[0039] S1.1: Perform zero-sequence circulating current in parallel system i z The real-time acquisition, and its instantaneous analog transmission to the DSP controller to complete the AD conversion. Among them, i z The numerical value of is one-third of the sum of the three-phase AC currents of the first inverter, namely: i z =1 / 3(i a1 + i b1 + i c1 ).

[0040] S1.2: Set the reference value i of the zero-sequence circulating current z_ref set to 0, and i z_ref with actual value i z Perform a difference operation, and the difference is recorded as △i z , namely: △i z = i z_ref -i z . At the same time, the △i z As the input of the "proportional + feedforward" zero-sequence circulating cur...

Embodiment 2

[0080] Embodiment 2 of the present disclosure provides a fault-tolerant control system based on zero-sequence circulation suppression, including:

[0081] The data acquisition module is configured to: acquire the running state data of the T-type three-level inverter parallel system;

[0082] The zero-sequence circulating current suppression module is configured to: add the three-phase modulation wave of any T-type inverter system to the output value of the zero-sequence circulating current controller based on the ratio and feedforward according to the obtained operating state data Realize zero-sequence circulation suppression;

[0083] The fault-tolerant control module is configured to: obtain the final state transition time of the fault phase according to the area equivalent criterion, reconstruct the switching sequence, and perform fault-tolerant control under the open-circuit fault of the switching tube without affecting the suppression of zero-sequence circulating current ...

Embodiment 3

[0086] Embodiment 3 of the present disclosure provides a computer-readable storage medium on which a program is stored. When the program is executed by a processor, the steps in the fault-tolerant control method based on zero-sequence circulating current suppression as described in Embodiment 1 of the present disclosure are implemented. , the steps are:

[0087] Obtain the operating status data of the T-type three-level inverter parallel system;

[0088] According to the obtained operating state data, the three-phase modulation wave of any T-type inverter system is added to the output value of the zero-sequence circulating current controller based on proportion and feedforward to realize zero-sequence circulating current suppression;

[0089] According to the area equivalent criterion, the final state transition time of the faulty phase is obtained, and the switching sequence is reconstructed. On the premise of not affecting the suppression of zero-sequence circulating current...

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Abstract

The invention provides a fault-tolerant control method and system based on zero-sequence circulating current suppression. The method comprises the following steps: acquiring operation state data of a T-type three-level inverter parallel system; according to the acquired operation state data, adding the three-phase modulation wave of any T-type inverter system and the output value of a zero-sequence circulating current controller based on proportion and feedforward to realize zero-sequence circulating current suppression; and according to an area equivalence criterion, obtaining the final state conversion time of a fault phase, reconstructing a switching sequence, and performing fault-tolerant control under the open-circuit fault of a switching tube on the premise that zero-sequence circulating current suppression is not affected. According to the invention, zero-sequence circulating current suppression and fault-tolerant control of the parallel system can be realized at the same time, and zero-sequence circulating current suppression and fault-tolerant control do not influence each other.

Description

technical field [0001] The present disclosure relates to the technical field of power systems, in particular to a fault-tolerant control method and system based on zero-sequence circulating current suppression. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. [0003] In low-voltage and high-power applications, parallel three-level inverter topology is usually used to increase the capacity level of the system, and at the same time, the efficiency and flexibility of the system are also improved. However, the parallel connection of T-type three-level inverters will cause zero-sequence circulating current, which will lead to increased system loss, distortion of grid-connected current, and seriously affect the service life of power circuit switch tubes. [0004] In addition, with the substantial increase in the number of power switch tubes in the par...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/483H02M7/5387H02M1/32H02J3/38
CPCH02M7/483H02M7/5387H02M1/32H02J3/38
Inventor 张承慧陈志远陈杰付有良邢相洋韩万青段彬
Owner SHANDONG UNIV
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