CN107728063B - A kind of direct-drive permanent magnet wind turbine generator group current transformer open-circuit fault diagnostic method - Google Patents
A kind of direct-drive permanent magnet wind turbine generator group current transformer open-circuit fault diagnostic method Download PDFInfo
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- CN107728063B CN107728063B CN201711217413.5A CN201711217413A CN107728063B CN 107728063 B CN107728063 B CN 107728063B CN 201711217413 A CN201711217413 A CN 201711217413A CN 107728063 B CN107728063 B CN 107728063B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention discloses a kind of open-circuit fault diagnostic methods of direct drive permanent magnetic wind generator system current transformer, first acquisition A, B, C three-phase current, carry out Park transformation respectively, obtain the electric angle of three-phase current；Then rotor angle locating for initial time motor is acquired, initial phase difference is calculated；Then rotor angle locating for the motor at current time is acquired, A, B, C three-phase motor relative mechanical angle is calculated, obtains diagnostic variable as difference with three-phase current electric angle；Finally determine whether to break down, determines failure pipe position.The present invention can fast and accurately detect the generation of current transformer open-circuit fault, determine the position of defective device rapidly, have to the fast-changing robustness of wind speed.
Description
Technical field
The present invention relates to wind generator system fault diagnosis technologies, are specifically related to a kind of direct drive permanent magnetic wind-power electricity generation system
The open-circuit fault diagnostic method of system current transformer.
Background technique
Current transformer is that the core component of direct drive permanent magnetic synchronous wind generating system and fragile link, current transformer once occur
Open-circuit fault, current transformer itself are almost unable to complete fault self-checking, such as handle not in time, gently then lead to power network current wave distortion
Power supply quality is reduced, operational reliability that is heavy then will will affect entire Wind turbines causes more catastrophe failure, or even jeopardizes power grid
Safety.Not only maintenance cost is high, maintenance time is long but also reduces the available of entire wind field for the disorderly closedown of wind power generating set
Hourage, and increase the recovery time of wind-powered electricity generation investment.Therefore, grid-connected wind generator system needs very high reliable
Property, and wind-driven generator operation conditions by wind speed variation influenced it is very serious, it is in the urgent need to address in the case where becoming wind friction velocity
The diagnosis and positioning of wind generator system failure improve the continuous service ability of Wind turbines, can under failure not between
Disconnected operation, and the normal energy between power grid is maintained to transmit.This requires systems can be quickly detected the generation of failure,
And it is capable of the position of accurate judgement fault element.
This research field has had some researchs at present, in the IGBT open circuit diagnostic method proposed at present, Duo Shuodou
It is the variation using electric current Park vector as judgment criteria, may determine that the generation being out of order by these variations, determine event
The position of barrier.In order to realize real-time diagnosis, this method needs to combine complicated mode identification method, cannot be integrated in drive control
In device.And most methods can not be carried out just for wind speed or metastable operating status is determined in the case where becoming wind friction velocity
The diagnosis and positioning of failure.The failure of generator-side converter wear can also be diagnosed by voltage, under IGBT open fault condition,
Voltage has irregular shape changing rule identical with electric current, equally may determine that the generation being out of order by the variation of voltage,
Determine the position of defective device.But this method needs to increase the cost of system using additional voltage sensor, together
When increased sensor also will increase the failure rate of system.Therefore, for the fault diagnosis of fan converter, it is necessary to which exploitation is new
Method for diagnosing faults, adapt to blower and become the running environment of wind speed, and realize that with simple method, the real-time of failure is examined
It is disconnected.
Summary of the invention
The purpose of the present invention is to provide a kind of open-circuit fault diagnosis sides of direct drive permanent magnetic wind generator system current transformer
Method can be convenient, the position of accurate detection defective device.
The technical solution for realizing the aim of the invention is as follows: the open-circuit fault of direct drive permanent magnetic wind generator system current transformer
Diagnostic method includes the following steps:
Step 1, acquisition A, B, C three-phase current, carry out Park transformation respectively, obtain the electric angle of three-phase current
Rotor angle locating for step 2, acquisition initial time motorr0, calculate the electric angle of every phaseWith n θr0It is initial
Phase differenceWherein n is the number of pole-pairs of magneto；
Step 3 acquires rotor angle locating for the motor at current timer, calculate A, B, C three-phase motor relative mechanical angleWith three-phase current electric angleDiagnostic variable is obtained as difference；
Step 4 judges that three diagnostic variables whether beyond given threshold range, if so, determining to break down, and turn
Fault location is carried out to step 5, otherwise, it is determined that not breaking down, and step 1 is gone to and continues to monitor；
Step 5, record diagnosis variablePositive and negative situation when beyond threshold value and when diagnostic variable corresponds to the moment beyond threshold value
The electric angle of each phaseThe corresponding table of non-zero vector effect section internal fault positioning is searched to tie if can determine that failure pipe position
Otherwise beam diagnosis records the mechanical angle at corresponding momentIt searches 0 vector effect section internal fault and positions corresponding table, determine
Failure pipe position.
Compared with prior art, the present invention its remarkable advantage are as follows: 1) proposed by the present invention fault diagnosis and localization method,
It can fast and accurately detect the generation of current transformer open-circuit fault, and determine the position of defective device rapidly, while having pair
The fast-changing robustness of wind speed；2) fault detection of the invention and fault location interact small, improve the safety of system
Property；3) present invention can be realized the current transformer fault diagnosis and location of real-time online, as long as detection part detects exception, system
Fault warning will be generated.
Detailed description of the invention
Fig. 1 is the PMSG wind power system structure chart of back to back structure of the present invention；
System construction drawing when Fig. 2 is the IGBT open-circuit fault of current transformer of the present invention；
Fig. 3 is the flow chart of fault detection method of the present invention；
Fig. 4 is electric angle and electromechanics that generator-side converter wear three-phase current Park is converted in wind speed variation
The comparison diagram of angle normal condition and T1 malfunction；
Fig. 5 is variation wave of the generator-side converter wear open-circuit fault diagnostic variable in T1 tube open circuit failure in wind speed variation
Shape；
When Fig. 6 is pusher side T1 tube open circuit failure, electrical angle that the diagnostic variable and electric current Park of pusher side failure convert
Degree variation waveform；
Fig. 7 is the flow chart that localization method when open-circuit fault occurs for pusher side IGBT pipe of the present invention；
Fig. 8 is diagnosis schematic diagram when open-circuit fault occurring within 0 vector action time.
Specific implementation method
The present invention program is further illustrated in the following with reference to the drawings and specific embodiments.
The topological diagram of PMSG wind power system back to back structure current transformer when Fig. 1, Fig. 2 give when generator-side converter wear one
When there is open-circuit fault in IGBT pipe, the topology diagram of system.In practical application, IGBT and with its antiparallel two pole
It manages while the probability to break down is minimum.So the present invention only considers the open-circuit fault of IGBT in current transformer, default with it instead simultaneously
The diode of connection still works normally.
As shown in figure 3, the open-circuit fault diagnostic method of direct drive permanent magnetic wind generator system current transformer, the inspection including failure
The positioning with failure is surveyed, steps are as follows:
Step 1, acquisition A, B, C three-phase current, carry out Park transformation respectively, obtain the electric angle of three-phase currentIts
InRefer to θcA、θcBOr θcC, calculation formula is respectively as follows:
Rotor angle locating for step 2, acquisition initial time motorr0, calculate the electric angle of every phaseWith n θr0It is initial
Phase differenceWherein n is the number of pole-pairs of magneto；
Step 3 acquires rotor angle locating for the motor at current timer, calculate the rotation of A, B, C three-phase motor relative mechanical
AngleWhereinRefer to θmA、θmBOr θmC, electric angle with three-phase currentDiagnostic variable is obtained as difference
Step 4 judges that three diagnostic variables whether beyond given threshold range, if so, determining to break down, and turn
Fault location is carried out to step 5, otherwise, it is determined that not breaking down, and step 1 is gone to and continues to monitor, when normal operation, is obtained
Diagnostic variableValue is approximately 0, it is contemplated that the presence of error sets fault diagnosis variable hereinJudge what fault-free occurred
Threshold range is [- 0.05,0.05]；
Step 5, record diagnosis variablePositive and negative situation when beyond threshold value and when diagnostic variable corresponds to the moment beyond threshold value
Three-phase current electric angleIt searches non-zero vector effect section internal fault and positions corresponding table, due to blower fan system unsteady flow
SVPWM (space vector modulation) mode is applied in device control strategy, therefore there are 0 vector action time, 0 vector action times
It is interior, fault location can not be carried out in such a way that the electric angle of electric current is in conjunction with diagnostic variable, therefore, need to judge electricity at this time
The mechanical angle of machineLocating section, search 0 vector effect section internal fault and position corresponding table, determine failure pipe position.When
Two-phase or when providing identical location determination more than two-phase, that is, be determined as fault location information, at this point, with location information obtain therefore
The diagnostic variable and location information for hindering phase are main basis on location, and the table of comparisons is as follows:
The non-zero vector of table 1 acts on section internal fault and positions corresponding table
20 vector of table acts on section internal fault and positions corresponding table
Fault detection part of the invention is suitable for the single tube and multitube open-circuit fault of generator-side converter wear IGBT, localization method
The open-circuit fault of an IGBT suitable for generator-side converter wear.
Embodiment 1
The present embodiment is illustrated method for diagnosing faults so that open-circuit fault occurs for pusher side T1 as an example.(the corresponding IGBT of T1
Position is as shown in Figure 1), the case where other IGBT open-circuit faults, diagnostic method is identical.
Detection for failure carries out Park transformation to the instantaneous value of three-phase current first, is then obtained by electric machines test
Angle, θ is rotated to current rotorr, calculated as follows: 1. calculating the electric angle of initial time A, B, C three-phase current(Refer to θcA、θcBAnd θcC) and n θr0Phase differenceWherein n is the number of pole-pairs of magneto.2. enabling(
Refer to θmA、θmBOr θmC), the mechanical angle of A, B, C three-phase motor is calculatedWith each corresponding electric angleIt is poor to make
Obtain diagnostic variable3. willJudged with given threshold, works as diagnostic variableWhen beyond threshold range,
Determine that open-circuit fault occurs.When operating normally, under the conditions of constant wind speed or random wind speed, diagnostic variableIt is approximately 0,
When an error occurs,Value can change, exceed threshold range, can be determined that break down at this time.Diagnostic variableWith
The control sensitivity of system is related, and when controlling sensitive enough, wind speed variation and load variation will not influence diagnostic variable
Value, but when failure,Threshold range will be exceeded.In view of the presence of error, fault diagnosis variable is setThreshold value
Are as follows: [- 0.05,0.05].When three-phase diagnostic variableIn two-phase or three-phase detection signal beyond setting threshold value when, that is, send out
It is out of order alarm, illustrates that open-circuit fault has occurred in generator-side converter wear.
Fig. 4 gives wind speed when quickly changing, generator-side converter wear three-phase current electric angleWith three-phase motor mechanical angle
Spend normal conditionWith the situation of change under T1 malfunction.As shown in Figure 4, wind speed is in all stage quickly to become
Change, is the open-circuit fault that T1 pipe occurs in 1s.Wind speed variation has an impact for motor electric angle and mechanical angle, but the two
Difference very little under normal circumstances, but when open-circuit fault occurs for T1 pipe, the bright of motor electric angle occurs in specific region
Aobvious distortion.The diagnostic accuracy of this method is demonstrated, and is had to the fast-changing robustness of wind speed.
It is as follows for the localization method of generator-side converter wear open-circuit fault: when diagnostic variable exceeds threshold value, to be counted as follows
It calculates: 1. calculating the positive and negative situation of diagnostic variable, 2. calculating current Park phase angle value compares the event in non-zero vector effect section
3. barrier positioning table positions the IGBT open-circuit fault that current transformer occurs if acting on the fault location table in section in non-zero vector
In there is no corresponding electric angle, then calculate electromechanics angle at this time, according to 0 vector effect section in fault location table
Carry out fault location.
In the present embodiment, open-circuit fault occurs in 1s for setting T1, and Fig. 5 gives failure detection result, at the 1s moment
Afterwards, variable is detectedExceed threshold value in specific region, be no longer held near 0, open-circuit fault occurs for judgement at this time；Work as open circuit
When fault-signal generates, fault location is carried out, Fig. 6 gives electric current Park phase angle θ under open-circuit faultcAAnd electromechanics
Rotate angle, θmACorrelation curve, according to the electrical angle angle value converted of electric current Park when breaking down or electromechanics
Angle value carries out the positioning of failure in conjunction with the positive and negative situation of diagnostic variable.Flow chart such as Fig. 7 institute of entire Fault Locating Method
Show.
Embodiment 2
If setting T1 tube open circuit failure to occur in 2.1s, electric angle caused by failure and mechanical angle comparison such as Fig. 8
Shown, failure start time belongs in 0 vector effect section at this time, by comparing the fault location in non-zero vector effect section
Table discovery, motor electric angle at this time in the fault location table in non-zero vector section, are not unable to complete the positioning to failure,
To interfere normal fault location.Fault location table in the mechanical angle angle value for calculating motor, with 0 vector effect section carries out
It compares, it is found that mechanical rotation angle is 5.89rad~0.33rad, the electromechanics angle when T1 tube open circuit failure of corresponding A phase
Section, to obtain the position of failure generation as T1 pipe.
Claims (6)
1. the open-circuit fault diagnostic method of direct drive permanent magnetic wind generator system current transformer, which comprises the steps of:
Step 1, acquisition A, B, C three-phase current, carry out Park transformation respectively, obtain the electric angle of three-phase currentWherein
Refer to θcA、θcBOr θcC；
Rotor angle locating for step 2, acquisition initial time motorr0, calculate the electric angle of every phaseWith n θr0Initial phase
DifferenceWhereinRefer to θfA、θfBOr θfC, n is the number of pole-pairs of magneto；
Step 3 acquires rotor angle locating for the motor at current timer, calculate A, B, C three-phase motor relative mechanical angleIts
InRefer to θmA、θmBOr θmC, and by three-phase motor relative mechanical angleWith three-phase current electric angleIt is diagnosed as difference
VariableWhereinRefer to θdA、θdBOr θdC；
Step 4 judges that three diagnostic variables whether beyond given threshold range, if so, determining to break down, and go to step
Rapid 5 carry out fault location, otherwise, it is determined that not breaking down, and go to step 1 and continue to monitor；
Step 5, record diagnosis variablePositive and negative situation when beyond threshold value and when diagnostic variable corresponds to moment each phase beyond threshold value
Electric angleSearch the corresponding table of non-zero vector effect section internal fault positioning terminates to examine if can determine that failure pipe position
It is disconnected, otherwise, record the mechanical angle at corresponding momentIt searches 0 vector effect section internal fault and positions corresponding table, determine failure
Pipe position.
2. the open-circuit fault diagnostic method of direct drive permanent magnetic wind generator system current transformer according to claim 1, special
Sign is that step 1 carries out Park transformation, formula to A, B, C phase current respectively are as follows:
Wherein, ia、ib、icRespectively indicate A, B, C three-phase current, iαA、iαB、iαCComponent of the three-phase current on α axis is respectively indicated,
iβA、iβB、iβCRespectively indicate component of A, B, C three-phase current on β axis, θcA、θcB、θcCA, B, C three-phase current is respectively indicated to exist
The angle of α, β coordinate system.
3. the open-circuit fault diagnostic method of direct drive permanent magnetic wind generator system current transformer according to claim 1, special
Sign is that A, B, C three-phase motor relative mechanical angle are in step 3
4. the open-circuit fault diagnostic method of direct drive permanent magnetic wind generator system current transformer according to claim 1, special
Sign is that the threshold range that step 4 is arranged is [- 0.05,0.05].
5. the open-circuit fault diagnostic method of direct drive permanent magnetic wind generator system current transformer according to claim 1, special
Sign is that non-zero vector effect section internal fault positions corresponding table in step 5 and 0 vector effect section internal fault positions corresponding table
It is respectively as follows:
The non-zero vector of table 1 acts on section internal fault and positions corresponding table
20 vector of table acts on section internal fault and positions corresponding table
6. the open-circuit fault diagnostic method of direct drive permanent magnetic wind generator system current transformer according to claim 1, special
Sign is, step 5 determines the switching tube failure when two-phase or when more than two-phase providing identical location determination.
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| CN109085447B (en) * | 2018-06-15 | 2019-10-08 | 南京理工大学 | Wind electric converter open-circuit fault detection method based on current amplitude |
| CN109917275B (en) * | 2019-04-01 | 2021-03-30 | 浙江众邦机电科技有限公司 | Fault detection method, system, device and readable storage medium |
| CN112147504B (en) * | 2019-06-27 | 2024-02-23 | 北京金风科创风电设备有限公司 | Fault detection method and device for converter and computer equipment |
| CN113109688B (en) * | 2021-04-19 | 2022-11-15 | 东南大学 | Thyristor open-circuit fault diagnosis method for excitation system of synchronous phase modulator |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5309075A (en) * | 1990-03-23 | 1994-05-03 | Toyoda Koki Kabushiki Kaisha | Digital servo-control apparatus for preventing torque variations |
| JP2005094826A (en) * | 2003-09-12 | 2005-04-07 | Hitachi Ltd | Speed controller and method for estimating pole position of synchronous motor |
| JP2005160287A (en) * | 2003-10-29 | 2005-06-16 | Daikin Ind Ltd | Method and arrangement for annular rotational position estimation as well as control method of motor control arrangement of motor |
| CN101510695A (en) * | 2009-03-31 | 2009-08-19 | 北京清能华福风电技术有限公司 | Double fed asynchronous wind power generator rotor side parallel-in control method |
| CN104459388A (en) * | 2014-11-26 | 2015-03-25 | 国家电网公司 | Permanent magnetic direct-drive wind power generation system integrated fault diagnosis method |
| CN105099154A (en) * | 2015-09-15 | 2015-11-25 | 湖南大学 | Open-circuit fault tolerance method for permanent magnet direct-drive wind power generation system converter |
| CN105158623A (en) * | 2015-05-22 | 2015-12-16 | 南京航空航天大学 | Three-phase bridge PWM rectifier switching tube open-circuit fault diagnosis method |
-
2017
- 2017-11-28 CN CN201711217413.5A patent/CN107728063B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5309075A (en) * | 1990-03-23 | 1994-05-03 | Toyoda Koki Kabushiki Kaisha | Digital servo-control apparatus for preventing torque variations |
| JP2005094826A (en) * | 2003-09-12 | 2005-04-07 | Hitachi Ltd | Speed controller and method for estimating pole position of synchronous motor |
| JP2005160287A (en) * | 2003-10-29 | 2005-06-16 | Daikin Ind Ltd | Method and arrangement for annular rotational position estimation as well as control method of motor control arrangement of motor |
| CN101510695A (en) * | 2009-03-31 | 2009-08-19 | 北京清能华福风电技术有限公司 | Double fed asynchronous wind power generator rotor side parallel-in control method |
| CN104459388A (en) * | 2014-11-26 | 2015-03-25 | 国家电网公司 | Permanent magnetic direct-drive wind power generation system integrated fault diagnosis method |
| CN105158623A (en) * | 2015-05-22 | 2015-12-16 | 南京航空航天大学 | Three-phase bridge PWM rectifier switching tube open-circuit fault diagnosis method |
| CN105099154A (en) * | 2015-09-15 | 2015-11-25 | 湖南大学 | Open-circuit fault tolerance method for permanent magnet direct-drive wind power generation system converter |
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