CN105871291B - One kind is used for frequency converter with common frequency power network without impact switching method - Google Patents
One kind is used for frequency converter with common frequency power network without impact switching method Download PDFInfo
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- CN105871291B CN105871291B CN201610224083.1A CN201610224083A CN105871291B CN 105871291 B CN105871291 B CN 105871291B CN 201610224083 A CN201610224083 A CN 201610224083A CN 105871291 B CN105871291 B CN 105871291B
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- power
- frequency
- frequency converter
- motor
- control
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
- H02P1/16—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
- H02P1/26—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual polyphase induction motor
- H02P1/28—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual polyphase induction motor by progressive increase of voltage applied to primary circuit of motor
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
- H02P3/06—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter
- H02P3/18—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing an ac motor
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Ac Motors In General (AREA)
- Inverter Devices (AREA)
Abstract
The invention discloses one kind to be used for frequency converter with common frequency power network without impact switching method, can realize soft of motor and can realize and the frequency converter of synchronized on, by installing two output current of frequency converter sensors additional, the realtime power of motor under pre- grid-connected operating mode is measured in real time, then frequency converter is switched into direct Power Control and the set-point of direct Power Control is set as to the realtime power of motor, then frequency converter and common frequency power network are together in parallel, after the completion of parallel connection, the power set-point of frequency converter is gradually reduced to zero, then frequency converter is cut off, realize that motor common frequency power network is powered.The soft stop process of motor is in contrast.The present invention as needed switches the control method of frequency converter between the control modes such as constant voltage constant frequency control and direct Power Control pattern; realize and switch under motor and its load soft start and soft stop operating mode between common frequency power network and frequency converter without impact; the no current breaking and closing of target power are reached; transient process existing for conventional method is avoided, improves the reliability of whole system.
Description
Technical field
The present invention relates to power electronic equipment, especially frequency converter loaded starting and switch to common frequency power network application neck
Domain.
Background technology
Rush of current caused by AC asynchronous motor across-the-line starting and torque shock ends can give electric power system and dragging system
Command to adversely affect, for needing loaded starting occasion typically to use variable frequency soft start scheme, i.e., with frequency converter drive motor
Started since zero-speed, raising speed of gradually boosting, until reaching its rated speed.Variable frequency soft start uses voltage/frequency in proportion
The methods of control, senseless control, overcurrent will not be produced；Starting torque equal to nominal torque can be provided, be adapted to
In the equipment for needing heavy duty or full load starting.
If frequency converter only undertakes the task of soft start, do not make speed governing operation, then reach specified in frequency converter drive motor
After rotating speed, motor is switched to the direct powered operation of common frequency power network, frequency converter can go to start other motor again.Example
Such as, the more pump constant pressure water supply systems of piping-main scheme are exactly a typical example.When hydraulic pressure is too high needs termination of pumping, in order to avoid " water
Hammer effect into shape ", do not allow to sudden shut off pump power, and require that gradually reducing rotating speed slowly stops.At this moment will be by motor again
Frequency converter dragging is switched to, realizes ramp to stop.Thus inevitably carry out mutually cutting between power network and frequency converter
Change operation.
Switch using between variable-frequency power sources and power frequency supply, mainly have the advantage that：1）The impact in switching can be reduced
Electric current, torque, the service life of extension device；2）With preferable energy-saving effect；3）Supply transformer can be greatly reduced
Capacity.
The switching method for being converted to power frequency mainly has following four：
1）Directly switch.Refer on the premise of ensureing that frequency converter is consistent with electric network source phase sequence, direct back brake switches power frequency
The amplitude, frequency and phase of voltage are not detected when power supply and variable-frequency power sources, directly switching.This mode requires system and protection energy
Enough allow the fluctuation and impact during switching, thus be rarely employed.
2）Asynchronised handover.Refer to the switching of the amplitude and frequency of detection voltage without detecting voltage-phase.During asynchronised handover most
When serious situation appears in 180 ° of the phase difference of frequency converter output voltage and line voltage, can cause very big surge voltage and
Electric current, 30 times or so of the maximum reachable rated current of dash current.This mode requires impact when system can allow switching
Change with torque, be normally only used for small-power low-voltage variable frequency system.
3）Synchronism switching.Refer to the switching of the amplitude for detecting voltage, frequency and phase.It can make to cut using synchronism switching technology
Change electric current and be no more than 2.5 times of Rated motor electric current, during synchronism switching, rotating speed changes very little before and after power frequency supply throws people.
4）Soft handover.Refer to after the amplitude, frequency and phase of detection voltage, control frequency converter output is the same as frequency, same to phase, amplitude
Controllable voltage, realize " unperturbed " switching.Soft handover has first to throw to cut and first cut afterwards throws two kinds of situations afterwards.Power frequency supply is switched to change
During frequency power, variable-frequency power sources is set to be consistent with motor side residual voltage phase first with phase-detection and lock phase control,
On the basis of the V/F of frequency converter keeps being basically unchanged, optimal high voltage converter switchover operation point is selected, adjusts frequency converter
Output voltage and frequency.So, motor basic non-impact current when putting into high voltage converter, the torque of motor are kept not substantially
Become.Variable-frequency power sources is switched to during power frequency, and with the phase and frequency of phase lock loop locks power frequency supply, control high voltage converter makes
Motor switches in the state of slightly higher than rated voltage and frequency.This way it is possible to realize high-voltage variable frequency power source and work
Soft handover between frequency power.
Problems be present in the switching that can be seen that existing variable-frequency power sources and power frequency supply from above-mentioned introduction：1）Power
Impact.Either power frequency supply is switched in variable-frequency power sources and either switch to variable-frequency power sources from power frequency supply, all exist fully loaded
The operation of operating mode deenergization or locking pulse, therefore power rush all be present to power network or variable-frequency power sources.2）Produce
Transient process.Motor load is inductive load, the unexpected disconnecting circuit in a perceptual loop, will necessarily produce the electricity that dammed
Pressure, impact is produced to corresponding component.3）Power supply dead band all be present in motor load.Because existing method is the current power supply electricity of excision
Source, another power supply then is put into, therefore motor certainly exists power supply dead band.
The content of the invention
In view of the deficiency above of prior art, it is an object of the invention to provide one kind to be used for frequency converter with common frequency power network without punching
Switching method is hit, when needing to carry out variable-frequency power sources with the load switching of power frequency supply band, bearing power can be controlled in power frequency supply
It is disconnected or closed without stream without flow point during so as to realize that excision or closed pair answer target power with the controllable switching of variable-frequency power sources.
The purpose of the present invention is realized by following means：One kind is used for frequency converter and switched with common frequency power network without impact
Method, by frequency converter, two frequency converter output voltage sensors TV1 and TV2, two output current of frequency converter sensor TA1
With TA2, two common frequency power network voltage sensor TV3 and TV4 and the switch K1 of frequency converter switching, control power frequency supply is controlled to throw
In the system for cutting K2 compositions, the realtime power of motor under pre- grid-connected operating mode is measured in real time, as needed by the controlling party of frequency converter
Method switches between the soft-start methods such as constant voltage constant frequency control and direct Power Control pattern, realizes motor and its load soft start
And switch under soft stop operating mode between common frequency power network and frequency converter without impact, including following processing procedure：
A. motor and its load switch to power frequency supply process by variable-frequency power sources：
1）Closure switch K2 frequency converters are started using conventional constant voltage constant frequency control mode, and starting accelerates to normal speed
Afterwards, realized pre- grid-connected, made using inverter output terminal voltage sensor TV1 and TV2, power frequency supply voltage sensor TV3 and TV4
Inverter output terminal voltage and power frequency supply voltage-phase, amplitude, frequency and phase sequence are completely the same；
2）After motor operation is stable, passed using frequency converter output voltage sensor TV1 and TV2, output current of frequency converter
Sensor TA1 and TA2 calculate the real-time active power and reactive power of motor under conditions present and are used as direct Power Control pattern
Lower active power reference P*, reactive power reference Q*；
3）Frequency converter is switched into direct Power Control, voltage magnitude signal, phase signal needed for direct Power Control
It is power frequency supply voltage signal, the power reference needed for direct Power Control is given as P*, Q*；
4）Closure switch K1, frequency converter and power frequency supply parallel running；
5）The power for reducing frequency converter is given to zero, and motor load power shifts according to certain speed to power frequency supply；
After the power output of frequency converter is reduced to zero completely, K2 is disconnected, realizes the excision of frequency converter；
B, motor and its load switch to frequency converter and soft stop process by power frequency supply：
1）Start frequency converter and use direct Power Control, the voltage magnitude signal needed for direct Power Control, phase
Signal is power frequency supply voltage signal, and it is zero that the power reference needed for direct Power Control is given；
2）Closure switch K2, by frequency converter and power frequency supply parallel running；
3）The power of frequency converter is given and is revised as motor actual power P*, Q*, and makes the real output of frequency converter
Rise according to certain speed, until the actual power of frequency converter reaches set-point；
4）Switch K1 is opened, cuts off power frequency supply；
5）The control strategy of frequency converter is switched into constant voltage constant frequency control, and realizes the soft stop of motor.
Described one kind is used for frequency converter with common frequency power network without impact switching method, is turned when being switched over by frequency converter
Change to direct Power Control realization.Its direct Power Control algorithm can use traditional switch list direct Power Control, work(
Rate feedforward direct Power Control, prediction direct Power Control etc..
Method disclosed by the invention, during by the way that variable-frequency power sources and power frequency supply being switched, the control mode of frequency converter is cut
Shift to direct Power Control and control the power output of frequency converter as requested, realize that target power no-load is in parallel and cut with no-load
Remove, so as to realize switching without impact for variable-frequency power sources and power frequency supply, thoroughly eliminate existing variable-frequency power sources and switch with power frequency supply
When transient process be present, avoid transient process to adverse effect caused by system, improve the reliability of system.
Brief description of the drawings
Fig. 1 is variable-frequency power sources and power frequency supply switching schematic diagram.
Fig. 2 is that the present invention uses frequency converter control system structure chart.
Fig. 3 is a kind of control figure for power feedforward that the present invention uses, main to include the calculating of load realtime power, lock phase
The links such as ring, feed-forward power control, modulation are formed.
Fig. 4 is the Power Control schematic diagram of the present invention,（a）For the adjustment schematic diagram of active power,（b）For reactive power
Adjustment schematic diagram, so that motor load power switches to common frequency power network by frequency converter as an example.
Embodiment
The invention will be further described with reference to the accompanying drawings and examples.
One kind is used for frequency converter with common frequency power network without impact switching method, by frequency converter, two frequency converter output voltages
Sensor TV1 and TV2, two output current of frequency converter sensors TA1 and TA2, two common frequency power network voltage sensor TV3 and
In the system that the switch K1 of TV4 and control frequency converter switching, control power frequency supply switching K2 are formed, it is characterised in that the system
Frequency converter can be realized when motor completes soft start by frequency converter and is powered with switching to common frequency power network after synchronized
Cut off with power network without grid-connected and frequency converter is impacted without stream.The switching schematic diagram of frequency converter and power frequency supply is as shown in Figure 1.
The frequency converter control system structure that the present invention uses as shown in Figure 2, in figureu ab、u bcFor inverter output terminal line voltage,i a、i b
For frequency converter output current phase, after frequency converter control system is to inverter output terminal voltage and current signal processing, frequency conversion is obtained
Active-power P, the reactive power Q that phase, amplitude and the frequency converter of device output end voltage export；u AB、u BCFor power frequency electric netting twine
Voltage, after frequency converter is handled, obtain the amplitude and phase of common frequency power network voltage；Control system is in the different stages using not
Same control mode, and the switching device for the pulsed drive inverter that sets out is generated, so as to form the output voltage of inverter.
A kind of power feedforward direct Power Control that the present invention uses is as shown in Figure 3.
Power Control schematic diagram disclosed by the invention is as shown in figure 4, its embodiment is as follows：
1st, motor and its load switch to power frequency supply by variable-frequency power sources：
1）Closure switch K2 frequency converters are started using soft starting modes such as conventional constant voltage constant frequency controls, and starting accelerates to volume
After constant speed degree, realized using inverter output terminal voltage sensor TV1 and TV2, power frequency supply voltage sensor TV3 and TV4 pre-
It is grid-connected, even if inverter output terminal voltage and power frequency supply voltage-phase, amplitude, frequency and phase sequence are completely the same；
2）After motor operation is stable, passed using frequency converter output voltage sensor TV1 and TV2, output current of frequency converter
Sensor TA1 and TA2 calculate the real-time active power and reactive power of motor under conditions present and are used as direct Power Control pattern
Lower active power reference P*, reactive power reference Q*；
3）Frequency converter is switched into direct Power Control, voltage magnitude signal, phase signal needed for direct Power Control
It is power frequency supply voltage signal, the power reference needed for direct Power Control is given as P*、Q*；
4）Closure switch K1, frequency converter and power frequency supply parallel running, but power frequency supply does not have power output now；
5）The power for reducing frequency converter is given to zero, and motor load power shifts according to certain speed to power frequency supply；
After the power output of frequency converter is reduced to zero completely, K2 is disconnected, realizes the excision of frequency converter.
2nd, motor and its load switch to frequency converter and soft stop by power frequency supply：
1）Start frequency converter and use direct Power Control, the voltage magnitude signal needed for direct Power Control, phase
Signal is power frequency supply voltage signal, and it is zero that the power reference needed for direct Power Control is given；
2）Closure switch K2, by frequency converter and power frequency supply parallel running；
3）The power of frequency converter is given and is revised as motor actual power P*、Q*, and make the real output of frequency converter by
Rise according to certain speed, until the actual power of frequency converter reaches set-point；
4）Switch K1 is opened, cuts off power frequency supply；
5）The control strategy of frequency converter is switched into the soft starting modes such as constant voltage constant frequency control, and realizes the soft stop of motor.
So, by the control to frequency converter, motor and its bearing power be can be achieved with variable-frequency power sources and power frequency supply
Between without impact switch, so as to avoid corresponding transient process.
The present invention is used for frequency converter with common frequency power network without impact switching method, it is possible to achieve soft of motor can simultaneously be realized and electricity
Net on synchronous frequency converter, by installing two output current of frequency converter sensors additional, measure motor under pre- grid-connected operating mode in real time
Realtime power, frequency converter is then switched into direct Power Control and the set-point of direct Power Control is set as the real-time of motor
Power, then frequency converter and common frequency power network are together in parallel, after the completion of in parallel, are gradually reduced the power set-point of frequency converter extremely
Zero, frequency converter is then cut off, realizes that motor common frequency power network is powered.The soft stop process of motor is in contrast.The present invention is according to need
The control method of frequency converter is switched between the two in soft starting modes such as constant voltage constant frequency controls with direct Power Control, realized
Switch under motor and its load soft start and soft stop operating mode between common frequency power network and frequency converter without impact, reached target electricity
The no current breaking and closing in source, avoid transient process existing for conventional method, improve the reliability of whole system.
Without departing from the spirit and scope of the present invention, those skilled in the art are without departing from the scope of the present invention
In the case of spirit, a variety of obvious modifications or change on form and details carried out to it all should fall in this hair
Within bright protection domain.
Claims (4)
1. one kind is used for frequency converter with common frequency power network without impact switching method, passed by frequency converter, two frequency converter output voltages
Sensor TV1 and TV2, two output current of frequency converter sensors TA1 and TA2, two common frequency power network voltage sensors TV3 and TV4
And in the switch K1 of control frequency converter switching, the system of control power frequency supply switching K2 compositions, pre- grid-connected operating mode is measured in real time
The realtime power of lower motor, as needed by the control method of frequency converter in constant voltage constant frequency control soft-start method and Direct Power
Control switches between the two, realizes nothing between common frequency power network and frequency converter under motor and its load soft start and soft stop operating mode
Impact switching, including following processing procedure:
A, motor and its load switch to power frequency supply process by variable-frequency power sources:
1) closure switch K2 frequency converters are started using conventional soft starting mode, after starting accelerates to normal speed, utilize frequency conversion
Device output end voltage sensor TV1 and TV2, power frequency supply voltage sensor TV3 and TV4 realize pre- grid-connected, export frequency converter
Terminal voltage and power frequency supply voltage-phase, amplitude, frequency and phase sequence are completely the same；
2) after motor operation is stable, frequency converter output voltage sensor TV1 and TV2, output current of frequency converter sensor are utilized
TA1 and TA2 is calculated under conditions present to be had under the real-time active power and reactive power of motor and conduct direct Power Control pattern
Work(power reference P*, reactive power reference Q*；
3) frequency converter is switched into direct Power Control, voltage magnitude signal, the phase signal needed for direct Power Control are
Power frequency supply voltage signal, the power reference needed for direct Power Control are given as P*, Q*；
4) closure switch K1, frequency converter and power frequency supply parallel running；
5) power for reducing frequency converter is given to zero, and motor load power shifts according to given speed to power frequency supply；Wait to become
After the power output of frequency device is reduced to zero completely, K2 is disconnected, realizes the excision of frequency converter；
B, motor and its load switch to frequency converter and soft stop process by power frequency supply:
1) start frequency converter and use direct Power Control, voltage magnitude signal, phase signal needed for direct Power Control
It is power frequency supply voltage signal, it is zero that the power reference needed for direct Power Control is given；
2) closure switch K2, by frequency converter and power frequency supply parallel running；
3) be revised as motor actual power P*, Q* by the power of frequency converter is given, and make the real output of frequency converter according to
Given speed rises, until the actual power of frequency converter reaches set-point；
4) switch K1 is opened, cuts off power frequency supply；
5) control strategy of frequency converter is switched into the control modes such as constant voltage constant frequency control, and realizes the soft stop of motor.
2. according to claim 1 be used for frequency converter and common frequency power network without impact switching method, it is characterised in that frequency converter
With power network without impact grid-connected and frequency converter without stream excision be by frequency converter soft start complete and realize with after synchronized,
Current transformer is switched into direct Power Control to realize；The direct Power Control method can use switch list direct Power Control,
Power feedforward direct Power Control, prediction direct Power Control method.
3. according to claim 2 be used for frequency converter and common frequency power network without impact switching method, it is characterised in that, the change
The power setting of frequency device direct Power Control low-converter, when in parallel with power network, the power of frequency converter is given as frequency converter fortune
Row is obtained when pre- and net state by sensor voltage transducer TV1 and TV2, the real-time survey calculations of current sensor TA1 and TA2
The numerical value arrived, namely motor give the realtime power under operating mode；When needing to cut off in frequency converter, frequency converter Direct Power is given
Definite value is reduced to zero by Rated motor operating mode set-point, then cuts off frequency converter again.
4. according to claim 2 be used for frequency converter and common frequency power network without impact switching method, it is characterised in that, frequency converter
The speed that power set-point is reduced to zero from the realtime power of Rated motor operating mode is cut off according to rated power, the frequency converter of motor
Time setting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201610224083.1A CN105871291B (en) | 2016-04-11 | 2016-04-11 | One kind is used for frequency converter with common frequency power network without impact switching method |
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| CN201610224083.1A CN105871291B (en) | 2016-04-11 | 2016-04-11 | One kind is used for frequency converter with common frequency power network without impact switching method |
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| CN105871291A CN105871291A (en) | 2016-08-17 |
| CN105871291B true CN105871291B (en) | 2018-03-20 |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107834864B (en) * | 2017-10-17 | 2019-08-20 | 西南交通大学 | A kind of combined power supply device direct Power Control method |
| CN108880402B (en) * | 2018-06-22 | 2021-11-19 | 卧龙电气集团辽宁荣信电气传动有限公司 | Phase-missing grid-connection method for high-power nine-phase motor |
| CN109245661B (en) * | 2018-09-29 | 2021-04-16 | 苏州英威腾电力电子有限公司 | Power frequency and frequency conversion switching circuit, control method, system, device and readable storage medium |
| CN110247424B (en) * | 2019-05-24 | 2023-04-28 | 上海电力学院 | Communication-free wind farm centralized variable frequency open loop constant voltage frequency ratio control method |
| CN110943673A (en) * | 2019-12-02 | 2020-03-31 | 新风光电子科技股份有限公司 | Control system and control method for frequency conversion and power frequency switching of high-voltage frequency converter |
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| CN105871291A (en) | 2016-08-17 |
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