外文文献翻译变频器设计使用参考.doc

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外文文献及译文
Converter reference design
(1) Converter Selection:
Selection to determine the frequency converter when the following points:
1) The purpose of a variable frequency; constant pressure to control or constant current control.
2) the load converter types such as leaves or pump volume pumps, with special attention to load the performance curve, the performance curve of the decision of the ways and means.
3) the frequency converter and load matching
Voltage match: a rated voltage converter with a rated voltage line with the load.
Current matches: ordinary pump, the rated current inverter and motor rated current match. For special load such as deep-water pumps, and so on need to refer to the electrical performance parameters to determine the most current inverter current and Guozainengli.
Torque match: in this case constant torque load or slow down when the device may have occurred.
4) the use of high-speed motor drive inverter, because of the high-speed motor, anti-small, high harmonics lead to increased output current value increases. So for high-speed motor inverter Selection, its capacity to be slightly larger than the ordinary motor selection.
5) If the frequency converter to a long cable run, this time to take measures to curb the long cable to the impact of capacitive coupling, inadequate efforts to avoid converter, so in this case, the drive to enlarge the capacity of a file or the converter Output installed output reactor.
6) For the application of some special occasions, such as high temperatures, high altitude, at this time would cause the down converter capacity, the drive to enlarge the capacity of a block.
(2) inverter control schematic design:
1) First confirmation of the installation environment Converter
Operating temperature: high-power converter is the internal electronic components, vulnerable to the effects of temperature, product general requirements for 0 ~ 55 ℃, but in order to ensure the safe, reliable, the use of room to be taken into account, the best control in 40 ℃ below. In the control box, the converter box should generally be installed in the upper and strictly comply with the Manual of installation requirements, absolutely not be allowed to heating elements or components easily fever close to the converter installed at the bottom.
Ambient temperature: the temperature is too high and large temperature changes, within easy converter there is dew, the insulation properties will be greatly reduced, or even short-circuit caused the accident. When necessary, to be added to the desiccant in the box and heater. In water treatment, generally heavier than water vapor, if the temperature changes, then this problem would be more prominent.
Corrosive gases: the use of the environment if the corrosive gas concentrations, will not only lead corrosion of components, printed circuit boards, but it will also accelerate the aging of plastic devices, reducing insulation properties.
Vibration and shock: the control cabinet with converter by vibration and mechanical shocks will cause electrical connection is bad. Huaian thermoelectric there such a problem. Apart from raising the control cabinet at this time of the mechanical strength, vibration and shock away from the source, we must also use seismic rubber pad fixed within and outside the control cabinet, such as electromagnetic switches have a vibration components. Equipment operation after a period of time and should conduct inspections and maintenance.
Electromagnetic interference: Inverter at work due to rectification and frequency, produce around a lot of electromagnetic interference, these high-frequency electromagnetic waves in the vicinity of the instrument, apparatus, a certain interference. Therefore, the cabinet instrumentation and electronic systems, it should be optional metal, shielding the inverter instrument interference. All the components should be reliable grounding, in addition, the electrical components, equipment and instrumentation should use the connectivity between the shielding control cables, and the shield should be grounded. If handled properly electromagnetic interference, often cause the entire system does not work, leading to the control unit failure or damage.
2) Drives and determine the distance between the electrical cables and wiring methods
Drives and motor the short distance should be as much as possible. This reduces the capacitance of the cable, reducing the emission source of interference.
Control cables optional shielded cable, power cable or optional shielding from the cable converter to use all the threads of the electrical shield.
Electric cables should be independent of the other cable alignment, the minimum distance of 500 mm. At the same time should avoid the electrical cables and other long-running cable lines, in order to reduce the output voltage inverter rapid changes in the electromagnetic interference. If the control cables and power cables cross, as far as possible so that they cross the 90-degree angle. Converter and analog signals on the line and back to the main line of separation of alignment, even in the case also in the control cabinet.
And the analog signal converter line the best choice of unshielded twisted pair, shielded power cables selection of the three-core cable (its specifications than ordinary electrical cables in the files) or to comply with the user manual converter.
3) inverter control schematics
Main circuit: the role of reactor is to prevent the high-frequency converter harmonic power through the input circuit to return to the grid by the impact of other electronic devices, in accordance with the capacity size converter to decide whether to increase reactor; filter Converter is installed in the output, the output of high-frequency converter to reduce harmonics, when the electrical inverter to the longer distance, we should install filters Although the frequency converter itself has all kinds of protection, but the lack of protection is not perfect, the main circuit breaker played overload, lack the same protection, selection, in accordance with the capacity to choose the frequency converter. Converter itself can be used to replace thermal overload protection relay.
Control loop: the frequency with the frequency manually switch to the failure frequency can be manually cut-operation, not because of output voltage, frequency and frequency-be interlocked.
4) Inverter grounding
Inverter correct grounding is to improve the system stability, the ability to inhibit an important means of noise. Inverter grounding resistance grounding terminal of the smaller the better, the grounding wire cross-section of not less than 4 mm, the length of not more than 5 m. Inverter should be grounded and power equipment to the sites separately, not in total. The shield signal converter from one end of the grounding end, the other floating air. Inverter and control of electrical between the same counter.
(3) Inverter Control Design
Converter should be installed in the control cabinet internal control counters in the design should pay attention to the following issues
1) heat: Inverter fever is the internal loss. In the frequency converter in the main part of the loss mainly to the main circuit, or about 98 percent, accounting for 2% of control circuits. In order to ensure reliable operation of the normal inverter, Thermal must inverter are usually used for cooling fan; converter fan of the contents of the converter box can be removed internal heat, if the fan does not work, should immediately stop inverter Operation; the high-power inverter also need to increase control Guishang fan, Control of the wind, to design a reasonable, all outlet into the net to set up dust, exhaust open, to avoid over the counter in a swirl, in a fixed location dust Accumulation, according to the statement converter ventilation fans to select the match, fans installed to the attention of earthquake problems.
2) the problem of electromagnetic interference
Converter in its work due to rectification and frequency, produce around a lot of electromagnetic interference, these high-frequency electromagnetic waves in the vicinity of the instrument, apparatus, a certain interference, and will produce high harmonics, the high harmonics will be available for adoption Xinhua loop into the whole power supply network, thus affecting other instruments. If the power inverter system as a whole lot of more than 25 percent, to be considered the anti-jamming measures to control supply.
When the system in the high-frequency welding machine such as the impact load, electroplating power, the converter itself will appear as interference protection, to consider the whole system of power quality problems.
3) protection issues need to pay attention to the following points
Waterproof anti-condensation: If the converter on the scene, the need to pay attention to the frequency converter Guishang not have the flange or other pipeline leak, the inverter can not be near the water splash, sum up the scene OEM Switchgear Kits & level of security to IP43 above.
BOOT: All outlet into the net to set up dust debris into the barrier floc, dust network should be designed to be removable, to facilitate the clean-up, maintenance. Dust of the grid network in accordance with the specific circumstances at the scene determined that dust around the net and Control Department to handle the combination of tight.
Anti-corrosive gases: the chemical industry in this relatively Most of this can be on the frequency counters in the control room.
(4) converter cable norms
Signal lines and power lines must be separately alignment: the use of analog signal converter for remote control in order to reduce the analog converter and other equipment from the interference, please control signal converter line with the strong electric circuit (H Circuit-and-loop) separate alignment. Distance should be 30 cm above. Even in the control cabinet, the same connection to maintain such a standard. The signal converter and the control should not be longer than the road back to 50 m.
Signal lines and power lines must be placed in different metal pipe or metal hose internal: connect PLC and the signal converter if not placed in metal tubes, Drives and vulnerable to external interference equipment; because the converter No built-in the reactor, so the converter input and output level of external power line will have a very strong interference, placing the signal lines of metal or metal hose has to be extended to the inverter control terminal, to ensure that the signal Line and the complete separation of power lines.
1) analog control signal line should use two-strands shielding line, cable specifications for 0.75 mm2. When the wiring must pay attention to, to the extent possible, the cable Baoxian short (5-7 mm or so), while Bao Xian after the shield should wrap insulating tape to prevent shielding lines and other equipment contact with the introduction of interference.
2) To improve the simple wiring and reliability, signal recommend the use of online video pressure bar.
(5) converter and the operation of the relevant parameters set
Inverter setting parameters, the parameters of each have a certain range of options, often encountered in the use of individual set of parameters for misconduct, leading converter does not work phenomenon.
Control: that is, speed control, transferred from the control, PID control or other means. To take control, according to the general control precision, the need for static or dynamic identification.
Running a minimum of: that is, the minimum speed motor running, the motor running at low speed, its poor performance cooling, electrical long run on low speed, it can cause burning motor. And at low speed, the cable will increase in the current, cable will lead to fever.
The maximum operating frequency: the general maximum frequency converter to 60 Hz, and some even to 400 Hz, high-frequency will enable high-speed motor operation, which the ordinary motor, its bearings can not be over-speed long run, whether the motor rotor To be capable of such a centrifugal force.
Carrier frequency: the higher the carrier frequency setting its high harmonics greater weight, and the length of cable, the electrical heating, cable converter fever fever and other factors are closely related.
Electrical parameters: the frequency converter to set parameters of the motor power, current, voltage, speed, maximum frequency, these parameters can be directly in the motor nameplate.
FH: In a frequency point, there may be a resonance phenomenon, particularly in the relatively high when the entire device in control of the compressor, the compressor to avoid the surge point.
(6) common fault analysis
1) flow failure: over-current fault can be divided into acceleration, deceleration, constant speed over-current. May be due to the increase in frequency converter too little time to slow down, load mutations, the unequal distribution of load, output short-circuit, and other causes. At this time can be extended by the general acceleration and deceleration time, reduce the load of mutations, plus braking energy components, load distribution design, the lines to be checked. If off-load converter or a failure that has been Central converter inverter circuits, to be replaced converter.
2) overload fault: overload fault, including frequency and overload the electrical overload. May be accelerated their time is too short, too low voltage power grids, Fuzaiguochong and other causes. General can be accelerated through the extension of time to extend the braking time, such as check-voltage power grid. Fuzaiguochong, selected motor and inverter can not drag the load, but also may be due to poor machinery lubrication caused. If the former is the need to replace high-power motors and inverter, if the latter will have to carry out maintenance on production machinery.
3) under-voltage: the importation of some of the power inverter that there are problems, need to check before you can run.
变频器设计使用参考
（1）变频器选型：
变频器选型时要确定以下几点：
1) 采用变频的目的；恒压控制或恒流控制等。
2) 变频器的负载类型；如叶片泵或容积泵等，特别注意负载的性能曲线，性能曲线决定了应用时的方式方法。
3) 变频器与负载的匹配问题
电压匹配：变频器的额定电压与负载的额定电压相符。
电流匹配：普通的离心泵，变频器的额定电流与电机的额定电流相符。对于特殊的负载如深水泵等则需要参考电机性能参数，以最大电流确定变频器电流和过载能力。
转矩匹配：这种情况在恒转矩负载或有减速装置时有可能发生。
4) 在使用变频器驱动高速电机时，由于高速电机的电抗小，高次谐波增加导致输出电流值增大。因此用于高速电机的变频器的选型，其容量要稍大于普通电机的选型。
5) 变频器如果要长电缆运行时，此时要采取措施抑制长电缆对