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Open-circuit fault detection method for three-phase inverter with phase-redundant fault-tolerant structure

A three-phase inverter, open-circuit fault technology, applied in the direction of instruments, measuring electricity, measuring devices, etc., can solve the problems of increasing the amount of calculation, increasing the cost, etc., to avoid false alarms, simple algorithms, and tolerance of fluctuations in detection variables. Effect

Inactive Publication Date: 2014-06-18
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0019] (1) It can only detect and locate the open-circuit fault of a single switch tube, but it is powerless to open-circuit faults of multiple switch tubes at the same time;
[0020] (2) The required reference voltage u in the two-phase stationary coordinate system α , u β It needs to be calculated separately in the general control system, so it will increase the amount of calculation;
[0021] (3) In order to eliminate the impact of load changes on open circuit fault detection, this method uses the DC bus voltage for normalization processing, which requires a bus voltage acquisition circuit, which increases the cost for some control systems

Method used

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  • Open-circuit fault detection method for three-phase inverter with phase-redundant fault-tolerant structure
  • Open-circuit fault detection method for three-phase inverter with phase-redundant fault-tolerant structure
  • Open-circuit fault detection method for three-phase inverter with phase-redundant fault-tolerant structure

Examples

Experimental program
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Embodiment

[0054] Figure 4 It is a schematic diagram of an open-circuit fault detection method for a three-phase inverter with a phase redundancy fault-tolerant structure of the present invention. like Figure 4 As shown, the three-phase inverter open-circuit fault detection method of the phase redundancy fault-tolerant structure of the present invention comprises the following steps:

[0055] S1: Obtain the desired voltage from the closed-loop control system of the motor drive system Then Converted to three-phase expected voltage after Clark coordinate transformation

[0056] S2: Calculate the detection variable dn. Different from the prior art, the present invention directly adopts the three-phase expected voltage mean of absolute value To perform normalization processing, so as to eliminate the impact of load changes, the calculation method is:

[0057] d n = u n...

example 1

[0083] 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 load torque is 50% of the rated load. Set detection variable threshold k m =0.08,k d =0.93. Figure 5 is the three-phase current of the motor in Example 1, and the detection variable d n and a n Waveform diagram. like Figure 5 As shown, the three-phase inverter in Example 1 has three faults: when time t=1.6s, T2 has an open circuit fault; when t=1.8s, both T1 and T2 have an open circuit fault; , T2 and T4 simultaneously open circuit fault.

[0084] a)t=1.4~1.6s, such as Figure 5 As shown, the three-phase current of the motor is a symmetrical sine wave, d n ≈0,a n ≈1, the inverter works normally, fault indication D a =D b =D c = 0,A a =A b =A c = H, according to the fault location table 1, it can be seen that there is no open circuit fault of the switching tube, and the three-phase inverter is worki...

example 2

[0089]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 load torque is 50% of the rated load. Set detection variable threshold k m =0.08,k d =0.93. Figure 6 is the three-phase current of the motor in Example 2, and the detection variable d n and a n Waveform diagram. like Figure 6 As shown, the three-phase inverter set in Example 1 has three faults: when t=1.6s, T1 has an open circuit fault; when t=1.8s, T1 and T4 have open circuit faults at the same time; T4 and T5 open circuit fault occurred simultaneously.

[0090] e)t=1.4~1.6s, such as Figure 6 As shown, the three-phase current of the motor is a symmetrical sine wave, d n ≈0,a n ≈1, fault indication D a =D b =D c = 0,A a =A b =A c = H, according to the fault location table 1, it can be seen that there is no open circuit fault of the switching tube, and the three-phase inverter is working normally; ...

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Abstract

The invention discloses an open-circuit fault detection method for a three-phase inverter with a phase-redundant fault-tolerant structure. The method comprises the following steps: normalizing a three-phase expected voltage to obtain a detection variable (dn) of the three-phase expected voltage; calculating to obtain a detection variable (an) according to an average value of an absolute value of the three-phase expected voltage; judging to obtain fault indications (Dn and An) through threshold values (km and kd) of the detection variable (dn) and the detection variable (an); searching and locating a switch tube having an open-circuit fault in a fault location table I according to the fault indications (Dn and An). Faults with three possibilities in the fault location table I can be further located by using a method of replacing a bridge arm, on which the switch tube determined to have the open-circuit fault is positioned, with a redundant fourth bridge arm. The method is applied to open-circuit fault detection of the three-phase inverter in a driving control system of an electric vehicle, at most 27 open-circuit faults can be detected, and an accurate basis is provided for fault-tolerant control and fault processing of the system.

Description

technical field [0001] The invention belongs to the technical field of three-phase inverter fault detection, and more specifically relates to a three-phase inverter open-circuit fault detection method with a phase redundancy fault-tolerant structure. Background technique [0002] In recent years, motor drive systems powered by voltage-source inverters have been widely used in electric vehicles, but the inverters in them are extremely prone to failure. In order to improve the safety and reliability of electric vehicles, it is necessary to effectively detect, locate and isolate inverter faults in real time, and adopt fault-tolerant control. [0003] In order not to reduce the system performance, the most widely used at present is to adopt the phase redundancy fault-tolerant structure in the three-phase inverter. figure 1 It is a schematic diagram of a three-phase inverter with phase redundancy and fault-tolerant structure. like figure 1 As shown, in the three-phase inverter...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/02
Inventor 凡时财刘晓龙邹见效徐红兵
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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