CN205792314U - A kind of soft starter of continuous frequency conversion - Google Patents
A kind of soft starter of continuous frequency conversion Download PDFInfo
- Publication number
- CN205792314U CN205792314U CN201620679487.5U CN201620679487U CN205792314U CN 205792314 U CN205792314 U CN 205792314U CN 201620679487 U CN201620679487 U CN 201620679487U CN 205792314 U CN205792314 U CN 205792314U
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- Prior art keywords
- soft starter
- phase
- frequency conversion
- bridge
- motor
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Abstract
The utility model discloses the soft starter of a kind of continuous frequency conversion, belong to AC asynchronous motor launcher field.Of the present utility model being mainly characterized by by the way of using pulse width modulating technology to combine with space vector control algorithm realizes frequency conversion and bypass: during speed governing below power frequency, use pulse width modulation algorithm to realize the continuous frequency conversion of soft starter；Motor Successful startup also changes modulation system when reaching common frequency power network frequency, bypass-switching contr is realized with space vector control algorithm, thus realize the function that soft starter can exit after electric motor starting completes voluntarily, to solve the problem that can not bypass in soft starter of application of frequency converter, compensate for existing having grade adjustable speed soft starter can not the shortcoming of continuous frequency conversion.
Description
[technical field]
This utility model belongs to AC asynchronous motor launcher field, particularly to the soft start of a kind of continuous frequency conversion
Device.
[background technology]
AC induction motor has plurality of advantages, so it is widely used in industrial and agricultural production and national defence.But
During its across-the-line starting, starting current is up to 5-8 times of rated current, the highest, the biggest starting current to motor self,
Electrical network, load all adversely affect, and in order to overcome drawback that starting current is big, we generally use reduced voltage starting mode to start.
Traditional soft-starting method, the star-delta conversion decompression soft start begun to use the sixties such as twentieth century,
Stator circuit series reactor (or resistor) reduced voltage starting, frequency sensitive trheostat soft start, autotransformer soft-start by lowering voltage, prolong limit
The methods such as triangle starting, implement reduced voltage starting owing to being abutted against tentaculum switching voltage, although can reduce the purpose of electric current,
But cannot fundamentally solve to start instantaneous current spike shock problem, and these methods are reducing while starting current also
Reduce starting torque, play disorder of internal organs secondary pulse electric current and load can be produced torque shock ends；Simultaneously because by the shadow of power network fluctuation
Ring, once occur that line voltage floats downwards, motor rotation blockage, starting process catalyst band can be caused to carry the problems such as switching, start
Flatness is bad, and soft starting characteristic is the highest.
At present, widely used common three-phase thyristor soft-start by lowering voltage device, its structure is that every concatenation two mutually is anti-
IGCT in parallel, realizes reduced voltage starting by controlling the triggering moment of six IGCTs successively, and this soft start only changes
The virtual value of voltage and do not change the frequency of voltage.There are two significant drawbacks in the method: one, starting torque is little；Its
Two, it is impossible to change the rotating speed of stator field, start slip excessive, reversion when causing electric motor starting, shake severity.
Additionally, soft starter made by the most useful converter.It uses the motor-driven control system of VFC to have excellent
Good dynamic, static properties, speed-regulating range width, flatness are good, can meet requirement, but exist when electricity in starting performance
Machine is not easy the shortcoming exited after having started.Therefore, seek a kind of more perfect continuous frequency conversion soft starter to realize its
Application in terms of soft start is extremely necessary.
[utility model content]
The purpose of this utility model is to propose a kind of company being different from common soft starter and grading variable-frequency soft starting device
Continuous adjustable speed soft starter, it, on the basis of keeping traditional frequency conversion device main circuit topological structure good characteristic, realizes further
The function that adjustable speed soft starter can exit after electric motor starting completes voluntarily, solves the difficulty existing for original adjustable speed soft starter
With the deficiency of bypass changeover to power frequency, so that its a tractor serves several purposes, do not leave unused.
For achieving the above object, the technical solution of the utility model is as follows:
The soft starter of a kind of continuous frequency conversion, including three-phase commutation bridge, three phase inverter bridge and microprocessor；Described three-phase is whole
The leading-out terminal of stream bridge is connected by dc bus with the end of incoming cables of three phase inverter bridge, the end of incoming cables of described three-phase commutation bridge, three-phase
The leading-out terminal of inverter bridge is connected formation major loop respectively with electrical network and motor；The leading-out terminal of three phase inverter bridge and electrical network and motor
Between be all in series with contactless contactor；Described microprocessor controls three phase inverter bridge and realizes the varying frequency starting of soft starter.
Also include detection module；Described detection module connects the outfan of electrical network, dc bus and three phase inverter bridge
Outfan, be respectively used to detect the voltage of three and current value；Microprocessor is connected with detection module and carries out three phase inverter bridge
Control.
The resistance-capacitance absorption that resistance R is in series it is parallel with electric capacity C on the dc bus of the leading-out terminal of described three-phase commutation bridge
Branch road.
The switching device of described three phase inverter bridge is IGBT pipe, constitutes six brachium pontis, wherein IGBT pipe V1 Yu V4, IGBT altogether
Pipe V3 Yu V6 and IGBT pipe V5 Yu V2 respectively constitutes three groups of upper and lower bridge arms.
Be respectively arranged with between leading-out terminal and U, V, W three-phase of motor of described three phase inverter bridge contactless contactor K1, K2,
K3；It is provided with contactless contactor K4, K5, K6 between A, B, C three-phase and the motor of electrical network.
By above technical scheme, this utility model has the advantages that
The main circuit of soft starter of the present utility model is by three-phase bridge diode rectifier circuit part and inverter circuit portion
Divide and constitute.By the testing circuit of voltage x current and phase place, line voltage is detected, by micro-to MCU for detection signal transmission
Processor, through the control algolithm of microprocessor thus export corresponding PWM ripple and realize the varying frequency starting of soft starter, when soft
Controlling inverter circuit when dynamic device output frequency reaches common frequency power network frequency, to make the three-phase voltage of motor have identical with line voltage
Frequency, amplitude and phase place so that can therefore avoid when converter bypasses electrical network and motor being produced rush of current and keeping away
Exempt from motor is produced the impact of electromagnetic torque.Converter is easily exited after electric motor starting completes, and solving converter should
The problem that can not bypass for soft starter, compensate for grade adjustable speed soft starter can not the shortcoming of continuous frequency conversion.Use contact
Motor is connected directly to electrical network by device switch designs, and adjustable speed soft starter is bypassed, thus realizes its most idle, a tractor serves several purposes
Function.
Further, middle resistance-capacitance absorption branch road is to solve the peak voltage problem being likely to occur in major loop.
The control method of the soft starter of above-mentioned a kind of continuous frequency conversion, becomes voltage permanent by the AC rectification of three phase network
Fixed DC voltage, then be frequency and the most adjustable alternating current of voltage with inverter by DC voltage conversion, and by using arteries and veins
Rush the mode that width modulation technology combines with PWM Algorithm and realize frequency conversion and bypass, not only improve common pressure regulation soft
Start and current-limiting soft-starting can not frequency conversion, shortcoming that torque is not enough, and continuous frequency conversion can be realized by inverter circuit part,
Adjustable speed soft starter can exit after motor Successful startup completes voluntarily.This utility model solves application of frequency converter in soft
The problem that dynamic device can not bypass, compensate for existing having grade adjustable speed soft starter can not the shortcoming of continuous frequency conversion.
Further, when detecting that peak voltage occur in bus two ends, by controlling the open-minded of 6 IGBT in inverter circuit
With shutoff so that three stator terminal of motor are in short-circuit condition, and energy discharges voluntarily, thus solves afterflow problem.
[accompanying drawing explanation]
Fig. 1 is the control circuit figure of the continuous frequency conversion soft starter using this utility model method；
Fig. 2 is three-phase mains voltage phasor diagram；
Fig. 3 is the space vector of voltage soft starter interval voltage vector diagram of each conducting；
Fig. 4 is the three phase mains oscillogram under space vector of voltage controls.
[detailed description of the invention]
In order to make operation principle of the present utility model, technical scheme more clear directly perceived, below in conjunction with the accompanying drawings to this practicality
Novel preferred embodiment elaborates.
1-3 referring to the drawings, the soft starter of a kind of continuous frequency conversion of this utility model, its main circuit is by full bridge rectifier portion
Dividing and constitute with inverter circuit part, left-half is uncontrollable rectifier bridge, and the AC rectification of three phase network is become voltage constant
DC voltage, then be frequency and the most adjustable alternating current of voltage with inverter by DC voltage conversion, middle resistance-capacitance absorption
Branch road is to solve the peak voltage problem being likely to occur in major loop.By voltage x current and the testing circuit pair of phase place
Line voltage detects, and detection signal transmission to MCU microprocessor thus is exported corresponding PWM ripple and realizes soft starter
Varying frequency starting；Controlling inverter circuit when soft starter output frequency reaches common frequency power network frequency makes the three-phase voltage of motor have
Frequency, amplitude and the phase place identical with line voltage so that can therefore avoid when converter bypasses electrical network and motor are produced
Give birth to rush of current and avoid motor is produced the impact of electromagnetic torque.
This utility model detailed description of the invention is, control circuit of the present utility model is by voltage, electric current, phase-detection mould
Block, MCU control module and main circuit part composition.By the testing circuit of voltage x current and phase place, line voltage is carried out
Detection, will detection signal transmission to MCU microprocessor, through the control algolithm of microprocessor thus to export corresponding PWM ripple real
The varying frequency starting of existing soft starter, controls inverter circuit and makes motor when soft starter output frequency reaches common frequency power network frequency
Three-phase voltage has frequency, amplitude and the phase place identical with line voltage so that can therefore keep away when adjustable speed soft starter bypasses
Exempt from electrical network and motor produce rush of current and avoids motor is produced the impact of electromagnetic torque；Its main circuit is mainly by three-phase
Rectifier circuit portion forms with inverter circuit part, and Fig. 1 is the control circuit figure of continuous frequency conversion soft starter, and it is a kind of friendship directly
The structural topology figure of ac frequency converter, the unidirectional current that power frequency three-phase electricity is converted to pulsation by three-phase bridge diode rectifier circuit is defeated
Going out, what the output with rectifier bridge was joined directly together is three-phase inverting circuit, and it uses IGBT as switching device, constitutes six bridges altogether
Arm.Wherein full-controlled device V1, V4, V3, V6 and V5, V2 respectively constitute three groups of upper and lower bridge arms, by controlling the open-minded of switching device
With shutoff to reach the purpose utilizing space vector control algorithm to realize frequency conversion.This kind of continuous frequency conversion is analyzed soft in conjunction with Fig. 2 with Fig. 3
Power frequency handoff procedure concrete in starter work process:
Specific works mode of the present utility model: below power frequency during speed governing, uses pulse width modulating technology to become
Frequency starts；When reaching power frequency, changing modulation system, control circuit uses space vector control algorithm and then controls inverter circuit
The purpose opening and turning off to reach to be easy to bypass changeover to power frequency of middle corresponding device.Conversion process uses the side of pulsewidth modulation
Method, motor Successful startup reaches to change modulation system, according to existing control of soft algorithm by electricity during common frequency power network frequency
The shutoff of corresponding device in the pressure hexagonal analysis of space vector and then control inverter circuit, now because using space vector control
Algorithm processed, the time that therefore two phase voltages and electrical network directly turn on is longer, for t=1/ (6 × 50Hz) s, it is simple to we can look for
Near zero-crossing point to motor biphase current switches over, thus uses contactless contactor design that motor is connected directly to electricity
Net, adjustable speed soft starter is bypassed, thus realizes its most idle, function of a tractor serves several purposes.Concrete rate-determining steps is as follows:
Realize the varying frequency starting of soft starter first with pulse width modulation algorithm, changed by the frequency changing modulating wave
The frequency of PWM waveform of output, i.e. controls the output frequency of converter, makes motor stator field frequency and rotor speed Tong Bu carry
Rising, relatively conventional soft starter reduces revolutional slip, reduces starting current, finally transits to power frequency, and then realize frequency conversion
Start.The process of varying frequency starting can use the control methods such as constant voltage and frequency ratio, vector controlled and Direct Torque according to real needs,
Making frequency amplitude consecutive variations, rotating speed is smooth to be promoted, and meets the requirement of motor stepless speed control, well solves electric motor starting and asks
Topic；Recycle space voltage vector control algorithm when motor reaches power frequency and realize the purpose of bypass changeover.At this selective analysis
When motor reaches power frequency, the control process of adjustable speed soft starter bypass changeover: combine Fig. 3 and understand, in Fig. 1 main circuit structure 6
The order of individual IGBT pipe conducting is followed successively by:
V1V2-V2V3-V3V4-V4V5-V5V6-V6V1.Three phase mains under controlling with specific reference to Fig. 4 space vector of voltage
Oscillogram is analyzed, and first starts triggering and conducting V1, V2 from a point, and U phase, W phase current start to increase, and then start to touch from b point
Sending out conducting V2, V3, V phase, W phase current also begin to increase, and then start triggering and conducting V3, V4 from c point, and now U phase current is in
Near zero-crossing point, so closing K4 and disconnecting K1 so that motor U phase is directly connected with electrical network A phase, V phase, A phase current start to increase
Add；After U phase bypasses, corresponding V1, V4 no longer triggers, and continues to start triggering and conducting V5 from d point, and W phase, A phase current increase, then
Starting triggering and conducting V5, V6 from e point, now V phase current is near zero-crossing point, so closing K5 and disconnect K2 so that motor
V phase is directly connected with electrical network B phase, and W phase, B phase current start to increase；After V phase bypasses, corresponding V3, V6 no longer triggers, and continues from f
Point starts triggering and conducting A, B phase, and A phase, B phase current increase, and then start to trigger V2 from g point, and now W phase current is in zero crossing
Near, so closing K6 and disconnecting K3 so that motor W phase is directly connected with electrical network C phase.So far, three-phase voltage from frequency conversion soft
Dynamic device completes bypass changeover process, thus realizes the function that soft starter can exit after electric motor starting completes voluntarily, to solve
Problem that certainly application of frequency converter can not bypass in soft starter, compensate for existing having grade adjustable speed soft starter can not continuous frequency conversion
Shortcoming.
In circuit running, the inductance in load has freewheel current and produces.Its concrete solution is as follows: such as figure
Shown in the control circuit figure of 1 continuous frequency conversion soft starter, resistance R, electric capacity C in figure absorb branch road.It is to solve major loop
The peak voltage problem being likely to occur in switching process；And the most inevitably produce in motor starting accelerator
Motor vibrating or some other reasonses cause the unexpected change of rotating speed, cause energy feedback phenomenon occur, thus occur in short-term
Between freewheeling state, now resistance R, electric capacity C device cannot absorb the biggest peak voltage, it is necessary to use insert no-voltage
The method of vector is controlled: when detecting that peak voltage occur in bus two ends, by controlling 6 IGBT in inverter circuit
Open and turn off so that three upper brachium pontis switches or three lower brachium pontis switches simultaneously turn on, and make threephase switch be in zero vector
Duty, now three stator terminal of motor are in short-circuit condition, and energy discharges voluntarily, thus solves afterflow problem.
Although embodiment of the present utility model being described above in association with accompanying drawing, but this utility model not limiting to
In above-mentioned specific embodiments, above-mentioned specific embodiments the most schematic, guiding rather than restricted
's.Those of ordinary skill in the art is under the enlightenment of this specification, claimed without departing from this utility model
In the case of scope, it is also possible to make a variety of forms, these belong to the row of this utility model protection.
Claims (5)
1. the soft starter of a continuous frequency conversion, it is characterised in that include three-phase commutation bridge, three phase inverter bridge and microprocessor；
The leading-out terminal of described three-phase commutation bridge is connected by dc bus with the end of incoming cables of three phase inverter bridge, entering of described three-phase commutation bridge
Line end, the leading-out terminal of three phase inverter bridge are connected formation major loop respectively with electrical network and motor；The leading-out terminal of three phase inverter bridge and
Contactless contactor all it is in series with between electrical network and motor；Described microprocessor controls three phase inverter bridge and realizes the change of soft starter
Frequency starts.
The soft starter of a kind of continuous frequency conversion the most according to claim 1, it is characterised in that also include detection module；Institute
The detection module stated connects the outfan of electrical network, dc bus and the outfan of three phase inverter bridge, is respectively used to detect electrical network defeated
Go out end, dc bus and the voltage of three phase inverter bridge outfan and electric current；Microprocessor is connected with detection module and carries out three contraries
Become the control of bridge.
The soft starter of a kind of continuous frequency conversion the most according to claim 1, it is characterised in that going out of described three-phase commutation bridge
The resistance-capacitance absorption branch road that resistance R and electric capacity C is in series it is parallel with on the dc bus of line end.
The soft starter of a kind of continuous frequency conversion the most according to claim 1, it is characterised in that opening of described three phase inverter bridge
Closing device is IGBT pipe, constitutes six brachium pontis altogether, and wherein IGBT pipe V1 Yu V4, IGBT pipe V3 Yu V6 and IGBT pipe V5 Yu V2 are respectively
Constitute three groups of upper and lower bridge arms.
The soft starter of a kind of continuous frequency conversion the most according to claim 1, it is characterised in that going out of described three phase inverter bridge
It is respectively arranged with contactless contactor K1, K2, K3 between U, V, W three-phase of line end and motor；A, B, C three-phase of electrical network and motor it
Between be provided with contactless contactor K4, K5, K6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620679487.5U CN205792314U (en) | 2016-06-30 | 2016-06-30 | A kind of soft starter of continuous frequency conversion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620679487.5U CN205792314U (en) | 2016-06-30 | 2016-06-30 | A kind of soft starter of continuous frequency conversion |
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| Publication Number | Publication Date |
|---|---|
| CN205792314U true CN205792314U (en) | 2016-12-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620679487.5U Expired - Fee Related CN205792314U (en) | 2016-06-30 | 2016-06-30 | A kind of soft starter of continuous frequency conversion |
Country Status (1)
| Country | Link |
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| CN (1) | CN205792314U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105939133A (en) * | 2016-06-30 | 2016-09-14 | 陕西科技大学 | Continuous variable frequency soft starter and control method thereof |
| CN106788113A (en) * | 2016-12-29 | 2017-05-31 | 深圳市英威腾电气股份有限公司 | A kind of frequency converter and its current-limiting method, system |
| CN109004865A (en) * | 2018-07-23 | 2018-12-14 | 陕西科技大学 | A kind of doube bridge arm ac-dc-ac inverter soft activator and control method |
-
2016
- 2016-06-30 CN CN201620679487.5U patent/CN205792314U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105939133A (en) * | 2016-06-30 | 2016-09-14 | 陕西科技大学 | Continuous variable frequency soft starter and control method thereof |
| CN106788113A (en) * | 2016-12-29 | 2017-05-31 | 深圳市英威腾电气股份有限公司 | A kind of frequency converter and its current-limiting method, system |
| CN109004865A (en) * | 2018-07-23 | 2018-12-14 | 陕西科技大学 | A kind of doube bridge arm ac-dc-ac inverter soft activator and control method |
| CN109004865B (en) * | 2018-07-23 | 2023-09-26 | 陕西科技大学 | Double-bridge arm AC-DC-AC variable frequency soft starter and control method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20161207 Termination date: 20170630 |