angular displacement (or line displacement) electromagnetic device, is a special kind of motor. General motor are continuous
rotation, and stepping motor have positioning and running two basic state, when a pulse input cubits stepping motor step by step
and rotation, each to rotating joints give it a pulse signal, it turned the certain Angle. Stepping motor angular displacement quantity and
input pulse is proportional to the number of strictly, in time and input pulse synchronization, so as long as the control input
pulse number, frequency and motor winding energized phase sequence, can obtain the needed Angle, speed and rotation direction.
In no pulse input, in winding power under the excitation of air gap magnetic field can make the rotor keep original position in
positioning state.
Stepping motor according to the output torque on the size of the points, can be divided into rapid stepping motor and power
stepping motor. Rapid stepping motor continuous high working frequency and output torque is small, usually in N · cm level, can
be used as a control small precision machine tool table (cases of linear cutting machine) can also and hydraulic torque
amplifier composition electrohydraulic pulse motor to drive nc machine tool's table, and power stepping motor output torque is
big is N · m level can be directly to drive the machine moving parts. Stepping motor according to
rotary union the excitation phase, can be
divided into three phase, four phase, five phase, six phase even eight phase. Generally speaking with phase increases, in the
same frequency, each phase guide electricity flow time increased, each phase average current will be higher, so that the motor
speed - torque characteristic will be better, step Angle is also small.
But as the phase increases, the size of the motor will
increase, the structure is complex, the multi-purpose 3 ~ 6 phase stepping motor. Due to the stepping motor speed along with the
input pulse frequency change and change, speed range is very wide, high sensitivity, output Angle can control, and output high
precision, and can realize synchronous control, so widely used in open loop system, also can be used in general universal
machine tool, improve feeding mechanism of automation level. Stepping motor according to its working principle to points,
basically have magnetoelectric and equation two categories, here only introduce common reaction stepping motor work principle,
we use the following step motor simplified diagram to illustrate.
In the motor stator has A and B, C three pairs of pole, pole round A coil, respectively called A phase, B and C phase, and rotor
is A toothed core, this kind of stepping motor called three-phase stepper motor. If the coil zhongtong with direct current, it
will produce A magnetic field, when A and B, C three pole coil in turn in electricity, then A, B, C three pairs of pole is in
turn take turns to produce A magnetic field to attract rotor rotation. First there is A phase coil (set to A phase) electricity,
the rotor 1, 3 two tooth be pole A absorb, rotor will stay in figure 5-5 A position. Then, A phase without electricity, 6
communicate electrical, the pole A magnetic field disappear pole B produced magnetic field, magnetic pole called magnetic fields
to the nearest 2, 4 two tooth attract the past, stop in figure B position, then rotor counterclockwise turned 30 °.
Then the
next phase power B, C communicate electrical. According to the same truth, rotor and counterclockwise turned 30 °, stop in the
diagram c position. If A mutually electricity, C phase off, then the rotor to reverse 30 °, make the pole A magnetic field to
2, 4 two tooth absorb. Stator each phase take turns to power on a rotor turned a tooth. According to such A - B - C - A - B - C
- A -... Order take turns to electricity, stepping motor is step by step according to the anti clockwise. Electricity coil each
conversion once, stepping motor rotate 30 °, we put the stepping motor each step turned Angle called step pitch Angle. If the
stepping motor power on coil conversion order upside down into A - C - B - A - C - B -... Order, the stepping motor will be made
according to
fiber optic rotary joint clockwise, so to change stepping motor rotation direction can be in any of the same electric.
2012年9月28日星期五
In the step (1) from the Angle, three-phase motor is better than two phase motor
(2) three-phase motor two phase excitation maximum keep the moment for 3 quality T1 (T1 for single-phase excitation torque), and two phase motor for quality 2 T1, so the
synthesis of three-phase motor torque.
(3) three-phase motor torque fluctuation ratio two-phase motor to small.
(4) three-phase motor continuous 2 steps for half step torque difference than two phase motor will be small.
[5] three-phase motor winding can star connection, and three terminal drive, excitation circuit transistor six;
And two phase motor is eight. [6] continuous operation, due to rotary joints three-phase stepper motor structure reason, the flux and current three harmonic is eliminated, so the vibration of the three-phase motor torque than two phase motor will be small. The conclusion is obvious. Another conclusion is HB motor is more suitable for low speed high torque purpose; RM type suitable for smooth running and speed is more than 1000 r/min purposes; And PM type low cost, in low speed vibration and high speed large torque, three-phase PM motor than two phase motor performance is better. Therefore, the current most development prospect, when is the hybrid stepping motor, and hybrid motor and to the following four direction: One of the development trends, is to continue along the direction of miniaturization. With the motor itself in the field of application of widening and all kinds of the continuous miniaturization, requirements and the related motor must also be more and more small, in 57, 42 frame size motor application after many years, now the base number to 39, 35, 30, 25 direction downward extension. Swiss ESCAP company also recently developed only 10 mm diameter of stepping motor.
The development trend of another, is change circular motor for square motor. Due to the motor using square model structure, make rotor may design better than large, round, so the moment volume ratio will be greatly improved. The same base number of the motor, square moment than round will be raised by 30% ~ 40%. The third development trend, the motor for integrated design. The rotor position sensor, reduction gear, etc and motor noumenon integrated design together, so make it easy to form a closed loop system, thus has better control performance. The development trend of four to rotary union five and three-phase motor direction. It is used widely in two and four phase motor, its vibration and noise is bigger, and five and three-phase motor has the dominance. And these two kinds of motor is concerned, five phase motor drive circuit than three-phase motor complex, so the three-phase motor system of performance to price than five phase motor better.
China's situation is different, until the 1980 s, has been magnetic resistance type stepping motor is dominant, hybrid stepping motor is 80 s began to fiber optic rotary joint development, is still the two kinds of structure type coexist. Although the new hybrid stepping motor completely may replace reluctance motor, but reluctance motor of the machine won the long-term use, for its technology is also more familiar, especially typical hybrid stepping motor's footsteps Angle (0.9 ° and 1.8 °) and the typical reluctance motor step pitch Angle (0.75 ° and 1.5 °), users change the product structure is not very easy, this makes two models of both the situation is in a relatively short period of change. This kind of present situation of stepping motor is adverse to the development of.
And two phase motor is eight. [6] continuous operation, due to rotary joints three-phase stepper motor structure reason, the flux and current three harmonic is eliminated, so the vibration of the three-phase motor torque than two phase motor will be small. The conclusion is obvious. Another conclusion is HB motor is more suitable for low speed high torque purpose; RM type suitable for smooth running and speed is more than 1000 r/min purposes; And PM type low cost, in low speed vibration and high speed large torque, three-phase PM motor than two phase motor performance is better. Therefore, the current most development prospect, when is the hybrid stepping motor, and hybrid motor and to the following four direction: One of the development trends, is to continue along the direction of miniaturization. With the motor itself in the field of application of widening and all kinds of the continuous miniaturization, requirements and the related motor must also be more and more small, in 57, 42 frame size motor application after many years, now the base number to 39, 35, 30, 25 direction downward extension. Swiss ESCAP company also recently developed only 10 mm diameter of stepping motor.
The development trend of another, is change circular motor for square motor. Due to the motor using square model structure, make rotor may design better than large, round, so the moment volume ratio will be greatly improved. The same base number of the motor, square moment than round will be raised by 30% ~ 40%. The third development trend, the motor for integrated design. The rotor position sensor, reduction gear, etc and motor noumenon integrated design together, so make it easy to form a closed loop system, thus has better control performance. The development trend of four to rotary union five and three-phase motor direction. It is used widely in two and four phase motor, its vibration and noise is bigger, and five and three-phase motor has the dominance. And these two kinds of motor is concerned, five phase motor drive circuit than three-phase motor complex, so the three-phase motor system of performance to price than five phase motor better.
China's situation is different, until the 1980 s, has been magnetic resistance type stepping motor is dominant, hybrid stepping motor is 80 s began to fiber optic rotary joint development, is still the two kinds of structure type coexist. Although the new hybrid stepping motor completely may replace reluctance motor, but reluctance motor of the machine won the long-term use, for its technology is also more familiar, especially typical hybrid stepping motor's footsteps Angle (0.9 ° and 1.8 °) and the typical reluctance motor step pitch Angle (0.75 ° and 1.5 °), users change the product structure is not very easy, this makes two models of both the situation is in a relatively short period of change. This kind of present situation of stepping motor is adverse to the development of.
2012年9月27日星期四
SCM has been in ac speed regulating system had been used widely. For example by Intel company 1983 years development and
SCM has been in ac speed regulating system had been used widely. For example by Intel company 1983 years development and
production of MCS - 96 series is the higher performance of the single chip microcomputer is one of the series, it is suitable
for high speed and high precision industrial control. The high-grade type: 8 x 196 KB, 8 x 196 kc, 8 x 196 MC in general open
loop ac speed regulating system of used more often.
Because ac motor control theory development, control strategy and control algorithm is also increasingly complex. Extended
kalman filtering, FFT, the state observer and adaptive control, artificial neural network and so on are applied to
rotating joints all kinds of
ac motor vector control and direct torque control of.
Therefore, DSP chip in all digital high performance ac speed regulating system find cast a stage. Such as TI company such as MCS320F240 DSP chip, with its high cost performance became full digital ac adjustable speed system preferred. TI company recently launched MCS320F240X series of products will be more price down to the level of the single chip microcomputer. In ac speed regulation of full digital process, various bus also play a very important role. STD bus, industrial PC bus, field bus and CAN bus in ac adjustable speed system automation application field play an important role. 3 PWM technology PWM control is the control of ac adjustable speed system core, any control algorithm and the ultimate realization of almost all kinds of PWM control mode is completed. Has been put forward and get the practical application of PWM control scheme is not more than ten kinds, about PWM control technology based on the many famous electric power international conference, such as PESC, IECON, EPE annual meeting has formed special.
Especially microprocessor application in PWM technology and digital later, pattern is unceasingly, from the pursuit of the voltage waveform sine, to the current waveform of sine, then to rotary union magnetic flux of sine; From the optimal efficiency, torque ripple at least, to eliminate noise and so on, PWM control technology development has experienced a constant innovation and improvement process.
So far, there are new scheme continuously put forward, further proves that this technology is in the ascendant. Among them, the space vector PWM technology to the voltage utilization ratio is high, the control algorithm is simple, current harmonic characteristics such as small in ac speed regulating system got more and more application. 4 high pressure large capacity ac speed regulation system In the small power ac speed regulation, because foreign product scale effect, make domestic manufacturer in price, process and technology are unable to fiber optic rotary joint fight. And in high voltage power, foreign companies and left us catch up space. First of all, foreign power grid voltage level general for 3000 v, and China's power grid voltage class for 6000 v and 10000 v; Secondly, high pressure high power ac speed regulating system can't large-scale batch production, and foreign labor cost, especially have certain professional knowledge labor cost is higher.
Therefore, DSP chip in all digital high performance ac speed regulating system find cast a stage. Such as TI company such as MCS320F240 DSP chip, with its high cost performance became full digital ac adjustable speed system preferred. TI company recently launched MCS320F240X series of products will be more price down to the level of the single chip microcomputer. In ac speed regulation of full digital process, various bus also play a very important role. STD bus, industrial PC bus, field bus and CAN bus in ac adjustable speed system automation application field play an important role. 3 PWM technology PWM control is the control of ac adjustable speed system core, any control algorithm and the ultimate realization of almost all kinds of PWM control mode is completed. Has been put forward and get the practical application of PWM control scheme is not more than ten kinds, about PWM control technology based on the many famous electric power international conference, such as PESC, IECON, EPE annual meeting has formed special.
Especially microprocessor application in PWM technology and digital later, pattern is unceasingly, from the pursuit of the voltage waveform sine, to the current waveform of sine, then to rotary union magnetic flux of sine; From the optimal efficiency, torque ripple at least, to eliminate noise and so on, PWM control technology development has experienced a constant innovation and improvement process.
So far, there are new scheme continuously put forward, further proves that this technology is in the ascendant. Among them, the space vector PWM technology to the voltage utilization ratio is high, the control algorithm is simple, current harmonic characteristics such as small in ac speed regulating system got more and more application. 4 high pressure large capacity ac speed regulation system In the small power ac speed regulation, because foreign product scale effect, make domestic manufacturer in price, process and technology are unable to fiber optic rotary joint fight. And in high voltage power, foreign companies and left us catch up space. First of all, foreign power grid voltage level general for 3000 v, and China's power grid voltage class for 6000 v and 10000 v; Secondly, high pressure high power ac speed regulating system can't large-scale batch production, and foreign labor cost, especially have certain professional knowledge labor cost is higher.
At present, the research more high power inverter circuit are
Multilevel voltage inverter
Transformer coupling of multiple pulse inverter
Hand over frequency converter
Doubly-fed ac frequency conversion speed control system
(1) level voltage inverter
Japan nagaoka university of science and technology, A.N abae in 1980 in IAS annual meeting for the first time put forward three
level inverter, also rotary joints called Neutral clamp type (Neutral Point Clamped) inverter. It is the emergence of high pressure and large
capacity voltage inverter research opens up a new way of thinking.
Multilevel voltage inverter and ordinary double level compared to the inverter has the following advantages:
1. The more suitable for large capacity, high voltage occasions.
2. Can produce M layer trapezoidal output voltage, the staircase to modulation can get very good approximate sine wave, theoretically improve level number can be close to pure sine wave type, harmonic content is small.
3. Electromagnetic interference (EMI) problem is reduced greatly, because the switch element a movement of the dv/dt usually only traditional double level 1 / (M - 1).
4. High efficiency, eliminate the same harmonic, the double level using PWM control switch frequency is high, the loss is big, and multilevel inverter can be used low frequency switch movement, the switching frequency is low, the loss is small, the efficiency improving. (2) transformer coupling of multiple pulse inverter Transformer coupling of multiple pulse inverter three level circuit, to get a more level will only each phase series unit inverter bridge the same number can be increased. Its advantages are:
1. Don't exist voltage balance problems. No clamp diode or capacitance, suitable for speed regulation control;
2. Modular degree good, easy maintenance,
3. To rotary union the same level as the number, the number of devices at least; 4. No clamp diode or capacity restriction, can realize more level, the higher the voltage, achieve more low harmonic,
5. Control method is relatively simple, can to each level respectively for PWM control, then waveform restructuring. This, of course, the shortage of the structure in need a lot of isolated dc power supply, the application of limited to some extent. (3) hand over frequency converter Hand over converter using thyristor as the main power device, in the mill and mine hoist drive has a lot of demand. Thyristor the biggest advantage is to switch the power (up to 5000 v / 5000 a), suitable for large capacity ac motor speed control system. At the same time, the high efficiency crystal thyratron production and technical function technique is quite mature, through with the modern ac motor control theory of digital combination, will have strong competitiveness. But hand over frequency converter, there exist some inherent defect: speed range is small, when the power supply is 50 hz, maximum output frequency not more than 20 hz; On the other hand, the power factor is low, the harmonic pollution is big, therefore need at the same time of the reactive power compensation and harmonic management.
(4) doubly-fed ac frequency conversion speed control system Doubly-fed ac frequency conversion speed control system of the frequency converter power of small, power factor adjustable, system reliability is higher, so fiber optic rotary joint recently received the attention of many researchers. Because of the frequency converter power account for only 25% of the motor capacity, so can greatly reduce the cost of the system. But, doubly-fed ac frequency conversion speed regulating system of motor need special design, can't use common asynchronous motor; And by the converter capacity and speed range restriction, does not have the ability of soft starter.
Multilevel voltage inverter and ordinary double level compared to the inverter has the following advantages:
1. The more suitable for large capacity, high voltage occasions.
2. Can produce M layer trapezoidal output voltage, the staircase to modulation can get very good approximate sine wave, theoretically improve level number can be close to pure sine wave type, harmonic content is small.
3. Electromagnetic interference (EMI) problem is reduced greatly, because the switch element a movement of the dv/dt usually only traditional double level 1 / (M - 1).
4. High efficiency, eliminate the same harmonic, the double level using PWM control switch frequency is high, the loss is big, and multilevel inverter can be used low frequency switch movement, the switching frequency is low, the loss is small, the efficiency improving. (2) transformer coupling of multiple pulse inverter Transformer coupling of multiple pulse inverter three level circuit, to get a more level will only each phase series unit inverter bridge the same number can be increased. Its advantages are:
1. Don't exist voltage balance problems. No clamp diode or capacitance, suitable for speed regulation control;
2. Modular degree good, easy maintenance,
3. To rotary union the same level as the number, the number of devices at least; 4. No clamp diode or capacity restriction, can realize more level, the higher the voltage, achieve more low harmonic,
5. Control method is relatively simple, can to each level respectively for PWM control, then waveform restructuring. This, of course, the shortage of the structure in need a lot of isolated dc power supply, the application of limited to some extent. (3) hand over frequency converter Hand over converter using thyristor as the main power device, in the mill and mine hoist drive has a lot of demand. Thyristor the biggest advantage is to switch the power (up to 5000 v / 5000 a), suitable for large capacity ac motor speed control system. At the same time, the high efficiency crystal thyratron production and technical function technique is quite mature, through with the modern ac motor control theory of digital combination, will have strong competitiveness. But hand over frequency converter, there exist some inherent defect: speed range is small, when the power supply is 50 hz, maximum output frequency not more than 20 hz; On the other hand, the power factor is low, the harmonic pollution is big, therefore need at the same time of the reactive power compensation and harmonic management.
(4) doubly-fed ac frequency conversion speed control system Doubly-fed ac frequency conversion speed control system of the frequency converter power of small, power factor adjustable, system reliability is higher, so fiber optic rotary joint recently received the attention of many researchers. Because of the frequency converter power account for only 25% of the motor capacity, so can greatly reduce the cost of the system. But, doubly-fed ac frequency conversion speed regulating system of motor need special design, can't use common asynchronous motor; And by the converter capacity and speed range restriction, does not have the ability of soft starter.
2012年9月26日星期三
Because the elevator is manned tool for drag system is reliable, but also to frequent deceleration and positive and negative
Because the elevator is manned tool for drag system is reliable, but also to frequent deceleration and positive and negative
turn, elevator dynamic characteristics and the improvement of reliability, and increased the elevator ride sense of security,
comfort and efficiency. In the past the elevator control dc is in the majority, in recent years gradually into rotating joints ac motor
frequency control of motor speed, whether Japan, or Germany. Our country a lot of elevator factory have vied with one another in
frequency control of motor speed to equip the elevator. Such as Shanghai mitsubishi, guangzhou Hitachi, Qingdao Fuji, tianjin
Otis adopts ac frequency control of motor speed. A lot of original production of elevator and variable frequency transformation.
Many people sit over shenzhen window of the world of monorail elevated touring car, the car driving frequent starting, parking,
uphill and downhill, and requirements on off smoothly, speed constant.
Because be manned vehicle, operation must be safe and reliable, perennial, that is to say, bad environment. Before the performance of speed for high drive, the adoption of the belt velocity feedback of vector control system, the price is higher. In order to lower the price, and convenient maintenance, we adopted universal converter torque vector control mode, successfully resolved the starting/acceleration, parking/reduction, constant speed/variable speed drive, etc., and prevent the "down", "impact station" phenomenon production, achieve the safe and reliable, the user is satisfied. This transformation is made by our company shenzhen electronics co., LTD.
Finished. Case 4, mixer class load Chemical, pharmaceutical industry mixer is very much, use frequency control of motor speed to replace other speed regulating mode, it has good. Northeast pharmaceutical factory hydrogenated fermentation post consists of eight table 6.5 tons of fermentation tank, motor power for 18.5 KW, belongs to rotary union gear speed control, such as the case of mixing speed change need to remove the triangle belt, was bulky and unsafe. Convert frequency control of motor speed, the annual energy saving 86000 KW, fermentation process improved obviously and improve the product quality, reduce the maintenance, only reduce triangle belt cost will save 30000 yuan, reduce the labor intensity, be beneficial to the factory, be beneficial to workers. And as: shijiazhuang HuaShu pharmaceutical factory with 10 sets of 315 kw converter drive mixer in pharmaceutical process production terramycin. Example 5, the injection molding machine class load The plastic injection machine is the key equipment of plastic molding processing, quantity, great power consumption. The past power saving mode for through the train type conversion Y type (star) to fiber optic rotary joint energy-saving, the effect is general.
The frequency converter speed control does not change the structure of the original injection molding machine, control oil pump several process pressure or flow (such as clamping, closing, shoot glue, the pressure, and demoulding, back mould, etc.), power saving 20% ~ 52%, better replace the past proportional valve throttle control way, greatly reduce the energy consumption and the pearl river delta for many of the injection molding factory has carried on the variable frequency transformation. Transformation injection molding machine, attention should be paid to joint acceleration, otherwise the yield decreased; Pay attention to the input and the output harmonic interference.
Because be manned vehicle, operation must be safe and reliable, perennial, that is to say, bad environment. Before the performance of speed for high drive, the adoption of the belt velocity feedback of vector control system, the price is higher. In order to lower the price, and convenient maintenance, we adopted universal converter torque vector control mode, successfully resolved the starting/acceleration, parking/reduction, constant speed/variable speed drive, etc., and prevent the "down", "impact station" phenomenon production, achieve the safe and reliable, the user is satisfied. This transformation is made by our company shenzhen electronics co., LTD.
Finished. Case 4, mixer class load Chemical, pharmaceutical industry mixer is very much, use frequency control of motor speed to replace other speed regulating mode, it has good. Northeast pharmaceutical factory hydrogenated fermentation post consists of eight table 6.5 tons of fermentation tank, motor power for 18.5 KW, belongs to rotary union gear speed control, such as the case of mixing speed change need to remove the triangle belt, was bulky and unsafe. Convert frequency control of motor speed, the annual energy saving 86000 KW, fermentation process improved obviously and improve the product quality, reduce the maintenance, only reduce triangle belt cost will save 30000 yuan, reduce the labor intensity, be beneficial to the factory, be beneficial to workers. And as: shijiazhuang HuaShu pharmaceutical factory with 10 sets of 315 kw converter drive mixer in pharmaceutical process production terramycin. Example 5, the injection molding machine class load The plastic injection machine is the key equipment of plastic molding processing, quantity, great power consumption. The past power saving mode for through the train type conversion Y type (star) to fiber optic rotary joint energy-saving, the effect is general.
The frequency converter speed control does not change the structure of the original injection molding machine, control oil pump several process pressure or flow (such as clamping, closing, shoot glue, the pressure, and demoulding, back mould, etc.), power saving 20% ~ 52%, better replace the past proportional valve throttle control way, greatly reduce the energy consumption and the pearl river delta for many of the injection molding factory has carried on the variable frequency transformation. Transformation injection molding machine, attention should be paid to joint acceleration, otherwise the yield decreased; Pay attention to the input and the output harmonic interference.
Example 6, sewage disposal and other environmental protection class load
Environmental protection is taken seriously more and more, it is related to human survival environment, even the Olympic bid
also have environmental index. Thus the clean energy, green city all appeared. Frequency control of motor speed available in
three aspects of environmental protection class load. One is the industrial wastewater treatment, 2 it is garbage power plant,
three is industrial smoke and exhaust and dust removal control. Such as guangzhou refinery, convert aeration machine sewage
treatment mixing equipment, USES the cage motor frequency control of motor speed, improve product reliability, save electricy
more than 40%, while improving the activated sludge microbial group of life, improve the sewage treatment effect.
Be like again foshan garbage power plant in the process selection of 52 table converter. Visible frequency control of motor speed has become the main equipment of environmental protection. China petrochemical corporation make a extinguished the torch (mainly refers to rotary joints the big oil refinery to burn gas) plan, that is the combustible gas delivery to use frequency control of motor speed compression machine cabinet recovery. Example 7, music fountain class load Very attract visitors to the music fountain, the water level of the amount and size is by frequency conversion control. Asian spray the highest of heyuan city, guangdong music fountain and scale a lot of shandong jinan quancheng square music fountain all belong to rotary union this, namely, power saving and effect is very good, in construction music fountain, attention should be paid to the harmonic frequency converter to control system of interference.
Example 8, cigarette machine class load Cigarette industry in the past imported cigarette machine, no matter Maureen 8, or Maureen 10, were not stepless speed regulation. Therefore, in the cigarette industry is mainly solve the stepless speed regulation and reliability problems, technology is simple, frequency converter usage simple, convergence greatly. The cigar mill of zhaotong city 19 sets of import grant 4 roll joint packaging integral unit using frequency control of motor speed, increase the cigarette, 200 cases, 200 cases of the cigarette tax quite 19 sets the price of frequency converter, namely one day disinvestment. Therefore, cigarette machine reconstruction rapidly, great benefit. Now most of the domestic machine is equipped with a variable frequency speed regulating function. Case 9, large kiln calcining class load Metallurgy, building materials, caustic soda and other large industrial turn furnace (bof) before most of them adopt dc, commutator machine, slip motor and speed regulating pole string. Because these speed regulating mode or fiber optic rotary joint , or low efficiency, in recent years, a lot of units by ac frequency conversion control, the effect is very good. ZhuZhou smeltery of zinc leaching residue volatilization kiln is the main body of zinc recovery equipment, a total of three table. Kiln outside diameter 2.8 meters, 44 meters long, the original with the positive flow son motor and slip motor drive, fault, often trip, a great quantity of maintenance.
Due to the bad environment, conductive dust, electric spark constantly. Brush, carbon brush change constantly, 90 minor repair 56 times, change only 1670 carbon brush, brush 647 only, serious influence the production. In June 91 the factory finished rotary kiln of frequency control of motor speed transformation. Smooth operation, reliable, simple operation, didn't happen because of motor drive fault and affect production. Annual energy saving 120000 degrees, over production is 1.1782 million yuan. Tangshan factory light grey calcined furnace is the key equipment of soda production, diameter 3.6 meters, furnace body length 30 meters, gross weight 266 tons, with 220 kw converter drive, low frequency start well, rotary stability, high reliability, improve the product quality, so that the calcined furnace production into the advanced ranks.
Be like again foshan garbage power plant in the process selection of 52 table converter. Visible frequency control of motor speed has become the main equipment of environmental protection. China petrochemical corporation make a extinguished the torch (mainly refers to rotary joints the big oil refinery to burn gas) plan, that is the combustible gas delivery to use frequency control of motor speed compression machine cabinet recovery. Example 7, music fountain class load Very attract visitors to the music fountain, the water level of the amount and size is by frequency conversion control. Asian spray the highest of heyuan city, guangdong music fountain and scale a lot of shandong jinan quancheng square music fountain all belong to rotary union this, namely, power saving and effect is very good, in construction music fountain, attention should be paid to the harmonic frequency converter to control system of interference.
Example 8, cigarette machine class load Cigarette industry in the past imported cigarette machine, no matter Maureen 8, or Maureen 10, were not stepless speed regulation. Therefore, in the cigarette industry is mainly solve the stepless speed regulation and reliability problems, technology is simple, frequency converter usage simple, convergence greatly. The cigar mill of zhaotong city 19 sets of import grant 4 roll joint packaging integral unit using frequency control of motor speed, increase the cigarette, 200 cases, 200 cases of the cigarette tax quite 19 sets the price of frequency converter, namely one day disinvestment. Therefore, cigarette machine reconstruction rapidly, great benefit. Now most of the domestic machine is equipped with a variable frequency speed regulating function. Case 9, large kiln calcining class load Metallurgy, building materials, caustic soda and other large industrial turn furnace (bof) before most of them adopt dc, commutator machine, slip motor and speed regulating pole string. Because these speed regulating mode or fiber optic rotary joint , or low efficiency, in recent years, a lot of units by ac frequency conversion control, the effect is very good. ZhuZhou smeltery of zinc leaching residue volatilization kiln is the main body of zinc recovery equipment, a total of three table. Kiln outside diameter 2.8 meters, 44 meters long, the original with the positive flow son motor and slip motor drive, fault, often trip, a great quantity of maintenance.
Due to the bad environment, conductive dust, electric spark constantly. Brush, carbon brush change constantly, 90 minor repair 56 times, change only 1670 carbon brush, brush 647 only, serious influence the production. In June 91 the factory finished rotary kiln of frequency control of motor speed transformation. Smooth operation, reliable, simple operation, didn't happen because of motor drive fault and affect production. Annual energy saving 120000 degrees, over production is 1.1782 million yuan. Tangshan factory light grey calcined furnace is the key equipment of soda production, diameter 3.6 meters, furnace body length 30 meters, gross weight 266 tons, with 220 kw converter drive, low frequency start well, rotary stability, high reliability, improve the product quality, so that the calcined furnace production into the advanced ranks.
2012年9月25日星期二
Second, the characteristics of variable frequency motor
1, the electromagnetic design
The common for asynchronous motor, then design the performance parameters of the main consideration is overload ability, starting performance, efficiency and power factor. And frequency conversion motor, because of the critical slip inverse ratio in power supply frequency, can be in critical slip close to 1 direct start, therefore, overload ability and start performance is not too much to rotating joints consider, and to solve the key problem is how to improve motor to non sine wave power adaptability. The general way is as follows:
1) as the decrease of the stator and rotor resistance. Reduce stator resistance can reduce the fundamental wave copper loss, to make up for the high order harmonic cause copper consumption increase
2) to rotary union control the current of high order harmonic, need to appropriately increase motor inductance. But rotor slot leakage reactance larger the skin effect is big also, high harmonic copper loss and increase. Therefore, motor leakage reactance size mus
3) frequency conversion motor main magnetic circuit general design into unsaturated state, one is considered high order harmonic will deepen the magnetic circuit saturation, 2 it is to consider in low frequency, in order to enhance the output torque and increasing converter output voltage. 2, structure design To structure the design, main is also considering non-sinusoidal power characteristic of frequency conversion motor insulation structure, vibration and noise cooling way of influence, generally pay attention to the following questions:
1) insulation level, general for F or higher level, strengthen on insulation and turn insulation strength, especially to insulation impact resistance voltage ability.
2) the motor of the vibration and noise problem, should fully consider motor components and overall rigidity, trying to improve its natural frequency, to avoid and every force wave produce resonance phenomenon.
3) cooling way: generally USES forced air cooling, namely main motor cooling fan using independent motor drive.
4) prevent shaft current measures, the capacity of more than 160 kw motor should adopt bearing insulation measures. Mainly is easy to produce magnetic circuit asymmetry, also can produce shaft current, when other high frequency component produced by the current together effect, shaft current will increase greatly, leading to bearing damage, so generally take insulation measures.
5) to fiber optic rotary joint constant power variable frequency motor, when the speed more than 3000 / min, should use high temperature resistant special grease, to compensate for bearing temperature. Frequency conversion motor can be at 0. 1 hz - 130 hz range for the long term operation, common motor can be in: 2 pole for 20-65 hz range long-term operation. 4 pole for 25-75 hz range long-term operation. Six pole for 30-85 hz range long-term operation. Eight pole for 35-100 hz range long-term operation.
1) as the decrease of the stator and rotor resistance. Reduce stator resistance can reduce the fundamental wave copper loss, to make up for the high order harmonic cause copper consumption increase
2) to rotary union control the current of high order harmonic, need to appropriately increase motor inductance. But rotor slot leakage reactance larger the skin effect is big also, high harmonic copper loss and increase. Therefore, motor leakage reactance size mus
3) frequency conversion motor main magnetic circuit general design into unsaturated state, one is considered high order harmonic will deepen the magnetic circuit saturation, 2 it is to consider in low frequency, in order to enhance the output torque and increasing converter output voltage. 2, structure design To structure the design, main is also considering non-sinusoidal power characteristic of frequency conversion motor insulation structure, vibration and noise cooling way of influence, generally pay attention to the following questions:
1) insulation level, general for F or higher level, strengthen on insulation and turn insulation strength, especially to insulation impact resistance voltage ability.
2) the motor of the vibration and noise problem, should fully consider motor components and overall rigidity, trying to improve its natural frequency, to avoid and every force wave produce resonance phenomenon.
3) cooling way: generally USES forced air cooling, namely main motor cooling fan using independent motor drive.
4) prevent shaft current measures, the capacity of more than 160 kw motor should adopt bearing insulation measures. Mainly is easy to produce magnetic circuit asymmetry, also can produce shaft current, when other high frequency component produced by the current together effect, shaft current will increase greatly, leading to bearing damage, so generally take insulation measures.
5) to fiber optic rotary joint constant power variable frequency motor, when the speed more than 3000 / min, should use high temperature resistant special grease, to compensate for bearing temperature. Frequency conversion motor can be at 0. 1 hz - 130 hz range for the long term operation, common motor can be in: 2 pole for 20-65 hz range long-term operation. 4 pole for 25-75 hz range long-term operation. Six pole for 30-85 hz range long-term operation. Eight pole for 35-100 hz range long-term operation.
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