Fan
analysisFan SupercapacitanceModulereliability
With the intensification of the energy crisis, renewable energy is developing rapidly,wind power system is also increasing. According to statistics20153050millionkW, a year-on-year increase31.5 percent, cumulative installed capacity1.45billion kilowatts.Wind Turbine Design and Manufacturing Technologyis also improving, which uses super capacitors.do energy storagechangepaddle systemis also very common.changepaddlesystembackup energy storage equipment,safety for fansandis very important, the more important its reliability becomes..in order to improve the reliability of the super capacitor, the real-time detection of the capacitor during the operation of the fan is highlighted.this articlejustcapacitancevoltageand capacity valuetworeal-time datacarried outanalysis.
voltage:the modulewith orovervoltage and undervoltage, whether a single module has overvoltage and undervoltage, and whether the voltage between modules is balanced.
value:meets the minimum capacitance value of the capacitor (I. e. at least meets the requirements of the fan1.5safe oars).
Common Capacitor Module Reliability TestProgramme
1.
throughchargerdetection
principle:throughchargerchargingdetectionSupercapacitanceModulevoltage, andCalculation of Super Capacitordiegroupvalue.
method:
(1)
charger detects whether the voltage of the capacitor module is normal,detectionCapacitancevoltage shall meet the formula:
Umin:super capacitor module(generally meet the requirements of pitch motor receiving voltage for 1.5 times).
Umax:Super Capacitor Module Mostlargeallowable voltage(for example: can notover rated voltage 10V).
otherwiseCapacitor Modulevoltageabnormal.
(2)
according to the formula:get the super capacitor module in orderI1 = total capacity at 3A charge, whereU1=80%UR,U2=40%URthe time point in the charging process of t1 and t2,URis the rated voltage of the super capacitor module. (See capacitancecapacityvaluecalculation diagram)
(3)
according to the formula:get the super capacitor module in orderI1= 4A (this value is not fixed) the total capacity during discharge, where U1 = 80% UR,U2 = 40% UR,t1, t2 at the time point in the discharge process, UR is the rated voltage of the super capacitor module.
(capacitancecapacityvalue calculation diagram)
(4)
calculating the results of discharge and multiple charging for more than two different currentsSupercapacitancediegroupvalueaverage is:.
(5)
calculation△CandSupercapacitanceModuleDesign tolerance deviationcoefficient,
shallmeet:
the capacitive modegroup capacity valueis normal.
advantages:charge and discharge processMedium value measurementis more accurate.charger can complete the test independently,The operation process is simple and does not requirepitch and mastercontrol is involved in too much control.
Disadvantages:is guaranteedFanis normal.run, itsprocess, the capacitor voltage is alwaysis normal.voltage state,it is difficult to achieve a complete charge and discharge process, the voltage may bechargingdetectioncircuit or communication circuitabnormal andtestis not accurate,at the same timecapacity value is alsocannot be calculated precisely.Even if the above process is fully realized, the fan will be shut down for a long time and cannot be operated, which will affect the operation.of the fanpower generation.
2.
detected by capacitive detection module
principle:SuperelectricitycapacityModuleelectrical circuit to add Hall sensor (I. e. current detection device)detection of the module,detected by capacitance monitoring modulethe voltage of the capacitor module and calculate the super electriccapacity modelgroup capacity value.
method:
(1)
Capacitance Monitoring Moduledetect whether the voltage of the capacitor module is normal,increase the voltage detection circuit.(I. e. add one to detect the voltages of two modules in five horizontal groups, see the schematic diagram of voltage detection circuit)
detectionthe resulting capacitancevoltageand voltageshall satisfy the formula:
and
.
otherwisecapacitanceModulevoltage.(2/5: The divided voltage detection circuit detects the voltages of the two modules, and its divided voltage U1 should meet the indicators of the total voltage 2/5U. It adds the voltage balance detection of the capacitor module.)
(capacitanceVoltage detection circuit diagram)
(2)
Collect current when charging and dischargingI.calculationthe super capacitor△Cthe method of its calculation and make.detection with charger is consistent.
(3)
by calculationthe resulting volume△Cupload to changepaddle systemcontroller, calculationSuper Capacitor ModuleDesign tolerance deviationcoefficient,shallmeet:
the capacitive modegroup capacity valueis normal.
advantages:Super Capacitor Moduleelectricitypressure detection is more accurate, at the same timealsocandetectionthe modulevoltagebalance, chargingdischarge processis more accurate, the charger requirementsComparisonand no needPitch and Mastercontrol is involved in too much control.
Disadvantages:added detection equipment(I. e., increased costs), whilethe same as the charger detection method, fanin, the voltage of the super capacitor module is always in the normal voltage state, so it is difficult to realize the complete charge and discharge process. At the same time, the voltage may be caused by the abnormality of the detection circuit or communication circuit of the capacitor monitoring module.testis not accurate, increase the fan failure rate,itscapacity value is alsocannot be calculated precisely. Even if the above process is fully realized, the fan will be shut down for a long time and cannot be operated, which will affect the operation.of the fanpower generation.
Newer CapacitorsModuleReliability Test Scheme
principle:Usepitchdrivecharges the super capacitor module and detects its voltage and sub-voltage.Utilizes Super CapacitorsModulepower supply,makeelectricitymachinePaddle closing or opening test. Bypitchmotor energy consumption calculation super capacitor modegroupvalue.
method(see flow chart):
(1)
Detected via pitch drivethe voltage and sub-voltage of the super capacitor module,the method and capacitance monitoring module to collect super capacitorModulevoltage methodthe same, the detected capacitor voltage and sub-voltage should meet:
and
.
otherwise, the voltage of the capacitor module is abnormal.
(2)
Selected by Main Control of FanFansuper capacitortest time, the requirement is per168hoursonce(the time interval can be set to meet the capacitance test frequency is preferred), time selected9:00and17:00(during the day, it is conducive to the timely maintenance of the staff who find abnormal fan during the test), and30seconds average wind speedshallsmallat the maximum test wind speed of the fan (generally8m/s, mainly for fan safety considerations). After the test conditions are met, the master control will stop the pitch to the limit and give the capacitancethe test start command.
(3)
After receiving the master control capacitor test command, changepaddle control"Paddle1"Open paddle to testpaddle angle (general choice60°and70° and less than 60 °, the test does not pass may affect the safety of the fan, and the test may be inaccurate if the energy consumption of the capacitor is less than 70 °.), DisconnectAC400Vand the driver (by automatically controlling the contactor or using the driver'ssemi-controlled bridgeDisconnectAC400both methods are available),Using Super Capacitor Modulepower supplypitchMotorat a constant speed (general choice3°/sand5°/sa constant speed) retractor to limit (92.5degrees).
(4)
Record "Paddle1"super capacitor before and after the paddle receiving voltage difference,
its calculation formula:△Uact1=Ur1-Uact1,
Uris the voltage of the super capacitor module before receiving the paddle,
Uactis the voltage of the super capacitor module after receiving the paddle..
among them△Uact1must satisfy:(capacitanceelectricityDifferential Pressure Normal Range)
Umax: Maximum variation voltage.
Tmax: Maximum torque of motor.
A: Test the paddle angle.
G:pitchratio constant.
η: motor efficiency.
C: Super capacitor module design capacity.
(capacitanceelectricityDifferential Pressure Normal Range)
(Control Flow Diagram)
(5)
throughpitch controlcalculating paddle1super capacitor variablepaddle process△C, the formula is as follows:
:should reclaim the oarsoronprocess.
A:test the paddle angle.
G: transformation ratio constant.
η: motor efficiency.
Computing Super Capacitor ModuleDesign tolerance deviationcoefficient,shallmeet:
the capacitive modegroup capacity valueis normal.
(6)
Repeat(3), (4), (5) Step respectively on the blade2, paddle3the super capacitor module for testing. Its voltage and capacity need to meet the above steps. During the test of a blade△UactandPcthe operating conditions are not met, the test is terminated and restored.AC400Vpower supply,and inform the control platformthe fan super capacitor module needs to be maintained or replaced.
advantages:Reduces Chargers and Capacitance Monitoring Devices,saves costs, its.Super Capacitor Modulevoltagedetection is more accurate. Through the driver, it can be judged whether the super capacitor module can meet the safety requirements of the fan. Detection is automatically triggered by software, no manual operation is required. The detection time is mostly in windless period, and the detection period is short and the detection time is not more than one time.180s, does not affectFanpower generation.this scheme simulates the real situation of the super capacitor module,also.candetected the super capacitorModuleworking circuit improves the safety of the fanandreliability.
Disadvantages:the reliability requirements of the software,At the same time, the requirements for the drive are higher, and the maintenance cost of the drive increases.scheme calculation is a fixed theoretical value, then.calculatedwillthere is a certain deviation, but the relative super capacitor voltage is rated voltage state,Use charger or capacitor monitoracquisitioncapacityvalues are more accurate.the programmelinkage requirements, the need for master controlsystemand changepaddlesystemare in the program. "out".
the extended usage of the scheme:
fanModuleservice life is approximately5years or so, it is necessary to predict the service life of the super capacitor of the fan.profituse this test schemewill be super every timecapacitanceModuletestcalculated△Uactand PC to database.through big data analyticsSupercapacitanceModule(its specific analysis method is not described in this paper),fit outthe modulevalueaging curve,can further predict the service life of the super capacitor and make more favorable arrangements for the owner to plan the use and maintenance of the super capacitor module.
(analog capacitancecapacityvalue aging curve)
Conclusion
the safety of the fan is an important part of the super capacitor module, its reliability requirements.very. Then during the operation of the fan, the capacitorModulereal-time detection methods also need to be more and more reliable.Whether it is the scheme mentioned in this article or other.better solution we are in line with the fan safety and low failure rate and consider. also hope goodscheme can be applied in large-scale wind turbines and contribute to the effective use of green energy.
(Author: Chengdu Fute Technology Co., Ltd.)
