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Current based open-circuit fault detection method for three-phase inverter

A three-phase inverter, open-circuit fault technology, applied in the direction of measuring electrical variables, instruments, measuring electricity, etc., can solve the problems of excessive calculation, increased calculation amount, slow detection, etc., to achieve small overall calculation amount, fast speed, avoidance of The effect of false alarms

Inactive Publication Date: 2015-05-06
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0017] (1) It can only detect and locate the open-circuit fault of a single switching tube of the inverter, but cannot detect the open-circuit fault of multiple switching tubes at the same time. To detect multi-tube open-circuit faults, additional detection variables must be added, which makes the method complicated , more calculations;
[0018] (2) The three-phase expected current i used n * Two coordinate transformations are required to obtain it, which will increase the amount of calculation and make the detection slower

Method used

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  • Current based open-circuit fault detection method for three-phase inverter
  • Current based open-circuit fault detection method for three-phase inverter
  • Current based open-circuit fault detection method for three-phase inverter

Examples

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Embodiment

[0044] figure 2 It is a flow chart of the current-based three-phase inverter open-circuit fault detection method of the present invention.

[0045] In this example, if figure 2 As shown, the current-based three-phase inverter open-circuit fault detection method of the present invention comprises the following steps:

[0046] (1), Obtain the motor three-phase current i from the motor drive control system n (n = a, b, c);

[0047] (2), according to the motor three-phase current i n Calculate the detection variable d of each phase n (n=a,b,c)

[0048] d n = 3 ( | i n | > - 2 i n > ) ...

example

[0063] In this embodiment, it is assumed that the rated power of the three-phase AC asynchronous motor is 1.1kW, the rated speed is 1390rpm, the rated torque is 7.6Nm, the rated current is 2.89A, and the detection variable threshold k 1 =-0.3,k 2 =0.3,k 3 = 1.8,k 4 = 3.3.

[0064] image 3 is the three-phase current of the motor and the detection variable d n waveform diagram.

[0065] In this example, if image 3 As shown, when the motor is at rated speed and 50% rated load, at time t=2s, T1 has an open-circuit fault; at t=2.2s, T1 and T2 have open-circuit faults at the same time; at t=2.4s, T1, T2 and T3 simultaneously open-circuit fault; the details are as follows:

[0066] When t=1.8~2s:

[0067] Such as image 3 As shown in (a), the motor phase current i a is a symmetrical sine wave, then d a ≈1, fault indication D a = 0; if image 3 As shown in (b), the motor phase current i b is a symmetrical sine wave, then d b ≈1, fault indication D b = 0; if image 3...

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Abstract

The invention discloses a current based open-circuit fault detection method for a three-phase inverter. The method comprises the steps of acquiring motor three-phase current in through a motor driving control system; performing weight processing for the cycle average value of the three-phase current and the cycle average value of an absolute value; normalizing to obtain a detection variable dn; comparing the detection variable dn with the preset threshold ki to obtain a fault indicator Dn of the three-phase inverter; positioning an inverter switching tube suffering from open-circuit fault from a fault positioning table according to the fault indicator Dn. The method is simple and easy to be carried out, and is suitably integrated to the control system.

Description

technical field [0001] The invention belongs to the technical field of three-phase inverter fault detection, and more specifically relates to a current-based three-phase inverter open-circuit fault detection method. Background technique [0002] With the widespread use of motor speed control systems in industrial applications, the safety of speed control systems has increasingly become the focus of attention. As an important part of the speed control system, the motor drive system's reliability is crucial to the safe operation of the speed control system. However, the reliability of the motor drive system is mainly affected by the power devices of the three-phase inverter. In order to improve the safety of the speed control system, the fault of the three-phase inverter is detected and located effectively in real time, and the corresponding fault-tolerant control is applied. appear indispensable. [0003] The power device failures of three-phase inverters can be attributed ...

Claims

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Application Information

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IPC IPC(8): G01R31/02
Inventor 凡时财徐安平邹见效徐红兵
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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