CN108196154B - Fault detection and fault positioning method for rotary rectifier of aviation three-stage synchronous motor - Google Patents

Abstract

The invention relates to a fault detection and fault location method for a rotating rectifier of an aviation three-stage synchronous motor. Whether the rotating rectifier is faulty is judged by the residual error of the distortion rate of the waveform. The sum of the maximum value and the minimum value of the current can be used to judge whether it is open circuit or open circuit and whether the upper arm diode or the lower arm diode is faulty, which can realize the function of fault diagnosis and location. Beneficial effects: whether the rotating rectifier is faulty can be accurately determined; which diode is short-circuited or open-circuited can be accurately located.

Description

Fault detection and fault positioning method for rotary rectifier of aviation three-stage synchronous motor

Technical Field

The invention belongs to the field of brushless electric excitation synchronous motor fault detection, and relates to a fault detection and fault positioning method for an aviation three-level synchronous motor rotating rectifier.

Background

In an aviation brushless electrically excited synchronous motor, an exciter rectifies output through a rotating rectifier to provide exciting current for a main generator. The rotating rectifier is more prone to failure than other parts due to the higher speed and temperature, and therefore failure detection of the rotating rectifier is of great significance. The fault of the rotating rectifier can be divided into a short circuit condition and a short circuit condition. Under the condition of short circuit, the current flowing through the diode can be increased sharply, and other normal devices can be further damaged if the protection is not carried out; in the case of an open circuit, the exciting current is reduced, the torque ripple is increased, and the load capacity of the motor is reduced. Therefore, before and after the system is operated and started, the rotating rectifier needs to be subjected to fault detection and positioning, and the workload of manual detection is reduced. It is therefore important to analyze how a diode can be identified and located in the event of an open circuit or short circuit.

At present, a plurality of methods for detecting faults of the rotating rectifier exist, and the following two methods are mainly used for the simple and practical method:

(1) an auxiliary winding method. The method is that a detection coil is arranged between the magnetic poles of the motor, and the signals obtained by the detection coil are processed and analyzed, so that the fault detection and positioning are carried out. This method requires a change in the structure of the motor, which increases the cost, and is not suitable for use particularly in a motor having a predetermined structure.

(2) The harmonic wave generated by fault of rotating rectifier is used to induce corresponding signal at stator side for detection. The method is characterized in that the fault identification and positioning are carried out on the rotating rectifier by analyzing signals on the stator side of the main generator or the stator side of the main exciter and adopting methods such as a threshold value method, an artificial intelligence algorithm, fuzzy mode identification and the like. Such methods require a large number of data samples to train.

Disclosure of Invention

Technical problem to be solved

In order to avoid the defects of the prior art, the invention provides a fault detection and fault positioning method for an aviation three-stage synchronous motor rotating rectifier.

Technical scheme

A fault detection and fault location method for an aviation three-stage synchronous motor rotating rectifier is characterized by comprising the following steps:

step 1: the method comprises the following steps of collecting stator side voltage and current of a main exciter of the aviation brushless electric excitation synchronous motor, and estimating rotor current of the main exciter through a stator flux linkage:

in the formula:

u_eαs、u_eβsis the exciter stator voltage; i.e. i_eαs、i_eβsIs the exciter stator current; r_es、L_esThe exciter stator resistance and inductance; m_esrThe stator and the rotor are mutually inducted; theta_erIs the rotor position; i.e. i_ear、i_ebr、i_ecrIs the exciter rotor current;

step 2: carrying out harmonic analysis on the estimated three-phase rotor current to obtain a harmonic distortion rate:

THD_x、THD_y、THD_z(x,y,z＝a,b,c；x≠y≠z)；

and step 3: calculate the residual of the distortion rate between any two phases:

R_z＝|THD_x-THD_y|；x,y,z＝a,b,c；x≠y≠z；

and 4, step 4: if the residual error meets the following formula, the system is normal, and the step 1 is repeated:

otherwise, the rotating rectifier is proved to be in failure;

K_th1is a predetermined value less than 0;

and 5: and (3) calculating the sum of the maximum value and the minimum value of the rotor current estimated in the step 1 in one period:

K_x、K_y、K_z(x,y,z＝a,b,c；x≠y≠z)；

step 6: with K_x、K_y、K_zAnd a threshold value K_th2And comparing to judge whether the circuit is short-circuit or open-circuit and positioning faults, wherein the judgment is based on the following table:

said K_th1Is 0.17.

The threshold value K_th2Is 1.0.

Advantageous effects

The fault detection and fault positioning method for the rotary rectifier of the aviation three-stage synchronous motor provided by the invention has the advantages that whether the rotary rectifier has a fault or not is judged through the distortion rate residual error of the waveform, if the rotary rectifier has the fault, whether the rotary rectifier is in an open circuit or an open circuit and whether an upper arm diode or a lower arm diode has the fault is judged through the sum of the maximum value and the minimum value of the phase current of the three-phase rotor of the main exciter in one period, and the fault diagnosis and positioning functions can be realized.

The method of the invention has the following beneficial effects:

(1) whether the rotary rectifier has a fault or not can be accurately judged.

(2) Which diode short circuit or open circuit can be accurately positioned.

Drawings

FIG. 1: schematic structural diagram of aviation three-stage synchronous motor

FIG. 2: rotor current estimated from system normality to D1 open circuit period

FIG. 3: rotor current estimated from system normality to D1 short circuit period

FIG. 4: three-phase rotor current waveform distortion rate THD change curve

FIG. 5: residual error change curve of three-phase rotor current waveform distortion rate

FIG. 6: curve of sum of maximum and minimum values of three-phase rotor current in one period

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

the embodiment comprises the following specific steps:

(1) for an aviation brushless electric excitation synchronous motor (see fig. 1), the stator side voltage and current of a main exciter are collected in real time, the rotor current of the main exciter is estimated through a stator flux linkage (see fig. 2 and 3), and the estimation formula is as follows:

in the formula:

u_eαs、u_eβsis the exciter stator voltage; i.e. i_eα_s、i_eβsIs the exciter stator current; r_es、L_esThe exciter stator resistance and inductance; m_esrThe stator and the rotor are mutually inducted; theta_erIs the rotor position; i.e. i_ear、i_ebr、i_ecrIs the exciter rotor current;

(2) carrying out harmonic analysis on the estimated three-phase rotor current to obtain a harmonic distortion rate

THD_x、THD_y、THD_z(x, y, z ≠ a, b, c; x ≠ y ≠ z), see FIG. 4.

(3) Calculate the residual of the distortion rate between any two phases:

R_z＝|THD_x-THD_y|；x,y,z＝a,b,c；x≠y≠z；

the resulting residual curve is shown in FIG. 5.

(4) If the residual error meets the following formula, the system is normal, and the step 1 is switched to, otherwise, a fault occurs:

K_th1is a predetermined value close to 0 and is 0.17. As can be seen from FIGS. 2, 3 and 5, the residual R is 0.05-0.1 s_a＜K_th1；R_b,R_c＞K_th1Indicating a fault at this point, which is consistent with an actual open fault of diode D1. From R within 0.15 to 0.2s_a＜K_th1；R_b,R_c＞K_th1It is known that a fault also occurs at this time, which coincides with an actual D1 open circuit fault. R is present for 0 to 0.05 and 0.1 to 0.15s_a,R_b,R_c＜K_th1It is shown that no failure occurred during this period, which is in line with reality

(5) And (3) solving the sum of the maximum value and the minimum value in one period for the rotor current estimated in the step 1: k_x、K_y、K_z(x,y,z＝a,b,c；x≠y≠z)

(6) Setting a threshold K due to actual interference_th2Is 1.0. By K_x、K_y、K_zAnd a threshold value K_th2The comparison is performed to determine whether the short circuit or the open circuit occurs and to locate the fault according to the following table 1. For example, K is present for 0.05 to 0.1s_a＜-K_th2；-K_th2＜K_b,K_c＜K_th2At this time, the diode D1 is open; k is in the range of 0.15 to 0.2s_a＞K_th2；K_b,K_c＜-K_th2It is known that the rotating rectifier diode D1 has a short-circuit fault at this time.

Fault location judging meter

The fault diagnosis and positioning provided by the invention are completely consistent with the actual state of the rotary rectifier, and can completely meet the requirements of diagnosis and positioning of short circuit or open circuit of one diode of the rotary rectifier.

Claims (3)

1. A fault detection and fault location method for an aviation three-stage synchronous motor rotating rectifier is characterized by comprising the following steps:

step 1: the method comprises the following steps of collecting stator side voltage and current of a main exciter of the aviation brushless electric excitation synchronous motor, and estimating rotor current of the main exciter through a stator flux linkage:

in the formula:

u_eαs、u_eβsis the exciter stator voltage; i.e. i_eαs、i_eβsIs the exciter stator current; r_es、L_esThe exciter stator resistance and inductance; m_esrThe stator and the rotor are mutually inducted; theta_erIs the rotor position; i.e. i_ear、i_ebr、i_ecrIs the exciter rotor current;

step 2: carrying out harmonic analysis on the estimated three-phase rotor current to obtain a harmonic distortion rate:

THD_x、THD_y、THD_z，x,y,z＝a,b,c；x≠y≠z；

and step 3: calculate the residual of the distortion rate between any two phases:

R_z＝|THD_x-THD_y|；x,y,z＝a,b,c；x≠y≠z；

and 4, step 4: if the residual error meets the following formula, the system is normal, and the step 1 is repeated:

otherwise, the rotating rectifier is proved to be in failure;

K_th1a predetermined value greater than 0;

and 5: and (3) calculating the sum of the maximum value and the minimum value of the rotor current estimated in the step 1 in one period:

K_x、K_y、K_z，x,y,z＝a,b,c；x≠y≠z；

step 6: with K_x、K_y、K_zAnd a threshold value K_th2And comparing to judge whether the circuit is short-circuit or open-circuit and positioning faults, wherein the judgment is based on the following table:

。

2. the aviation three-stage synchronous motor rotating rectifier fault detection and fault location method according to claim 1, characterized in that: said K_th1Is 0.17.

3. The aviation three-stage synchronous motor rotating rectifier fault detection and fault location method according to claim 1, characterized in that: the threshold value K_th2Is 1.0.

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