CN206807019U - Current three-phase imbalance compensation device based on three level NPC - Google Patents
Current three-phase imbalance compensation device based on three level NPC Download PDFInfo
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- CN206807019U CN206807019U CN201720632856.XU CN201720632856U CN206807019U CN 206807019 U CN206807019 U CN 206807019U CN 201720632856 U CN201720632856 U CN 201720632856U CN 206807019 U CN206807019 U CN 206807019U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
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Abstract
It the utility model is related to current three-phase imbalance compensation technical field, and in particular to a kind of current three-phase imbalance compensation device based on three level NPC, solve the problems, such as that existing current three-phase unbalancing device has that security reliability is low, loss is big and precision is low.Central processing unit in compensation device is connected by PWM isolated drive circuits with three level NPC transverters, and three level NPC transverters are connected by filter circuit with main circuit；Load current sampling unit and line voltage sampling unit are connected with main circuit respectively, between transverter output current sampling unit access filter circuit and main circuit；DC voltage sampling unit, IGBT temperature sampling unit connect with three level NPC transverters；Above-mentioned sampling unit is connected by analog signal conditioner circuit with AD signaling conversion circuits, and AD signaling conversion circuits are connected with central processing unit.The utility model has the advantages of more safe and reliable, compensation precision is higher, automatization level is higher.
Description
Technical field
It the utility model is related to current three-phase imbalance compensation technical field, and in particular to a kind of based on three level NPC's
Three-phase imbalance compensation device.
Background technology
In recent years, with the fast development of Power Electronic Technique and microcontroller technology, the production based on voltage source converter
Product are widely used.Network system three-phase imbalance phenomenon is extremely serious at present, adds circuit and distribution transformer
Electric energy loss, produce the zero-sequence current of distribution transforming, reduce motor efficiency.Meanwhile also easily triggering the heating of distribution transforming, reduction is matched somebody with somebody
Become and contribute, shorten equipment life, reduce the stable operation efficiency of system, the scaling loss of distribution transforming can be also caused when serious, influences electricity consumption
The safety and residential electricity consumption quality of equipment.Conventional phase-change switch improves three-phase imbalance phenomenon at present, but phase-change switch
10~30ms power failure can be caused during work, by adjusting load come integrally-regulated, process is not smooth enough.
Three-level current three-phase imbalance compensation device mainly has two kinds of main circuit topological structures：The capacitor-clamped level of formula three
Transverter and diode clamp formula (NPC).At present two kinds are mainly used on electricity market to solve current three-phase imbalance problem
Mode, as phase-change switch mode and two level converter compensation devices.Phase-change switch not enough smoothly has power failure when commutation be present
, there is the problem of security reliability low problem in phenomenon, two level converter compensation devices have the shortcomings such as loss is big, precision is low.
Utility model content
To solve the problems, such as that existing current three-phase unbalancing device has that security reliability is low, loss is big and precision is low,
The utility model provides a kind of more safe and reliable, higher current three-phase imbalance based on three level NPC of compensation precision
Compensation device.
The technical solution of the utility model is：
A kind of current three-phase imbalance compensation device based on three level NPC, including central processing unit, AD signals conversion electricity
Road, PWM isolated drive circuits, power supply, three level NPC transverters, analog signal conditioner circuit, filter circuit, load current are adopted
Sample unit, line voltage sampling unit, transverter output current sampling unit, DC voltage sampling unit and IGBT temperature sampling
Unit；Central processing unit includes CPLD and DSP, and central processing unit is connected by PWM isolated drive circuits and three level NPC transverters
Connect, three level NPC transverters are connected by filter circuit with main circuit；Power supply is connected with central processing unit；Load current samples
One end of unit and line voltage sampling unit is connected with main circuit respectively, one end access of transverter output current sampling unit
Between filter circuit and main circuit；One end and the three level NPC transverters of DC voltage sampling unit, IGBT temperature sampling unit
Connection；Load current sampling unit, line voltage sampling unit, transverter output current sampling unit, DC voltage sampling are single
The other end of member and IGBT temperature sampling unit is connected by analog signal conditioner circuit with AD signaling conversion circuits, AD signals
Change-over circuit is connected with central processing unit.
Further, in addition to protection circuit, central processing unit are also connected with analog signal conditioner circuit by protection circuit
Connect.
Further, in addition to man-machine interface, man-machine interface are connected with central processing unit.
Further, the CPLD of central processing unit is EPM1270, DSP TMS320F28335.
Further, DC voltage sampling unit, line voltage sampling unit include voltage Hall.
Further, transverter output current sampling unit includes current Hall and sampling resistor.
Further, load current sampling unit includes current transformer and sampling resistor.
Further, man-machine interface is provided with the serial communication interface SCI being connected with CPLD+DSP, Serial Peripheral Interface
SPI。
The utility model has the advantages that：
1. the utility model is the current three-phase imbalance compensation device based on three level NPC, detected by sampling unit
Voltage, electric current in load, by central processing unit CPLD+DSP be calculated load in negative phase-sequence and zero-sequence current, then
, size opposite electric current identical with negative phase-sequence and zero-sequence current phase in load, compensation electric current are produced by PWM isolated drive circuits
Cancelled out each other with the negative phase-sequence in load and zero-sequence current, be finally reached the purpose of compensation system power factor.
2. comparing two level current transformers, in three-level current transformer commutation process, it is total that each IGBT is solely subjected to DC side
The half of voltage, improves place capacity, reduces cost, and has the advantages that output current harmonics are low, electromagnetic interference is small.Support
Disappear the unbalanced component for needing in load current to compensate, and desired source current is finally given, so as to realize three phase network power
The a wide range of continuous accurate compensation of balance.
Brief description of the drawings
Fig. 1 is three level NPC main circuit topological structure figures；
Fig. 2 a are the positive sequence polar plots of the utility model embodiment；
Fig. 2 b are the negative phase-sequence polar plots of the utility model embodiment；
Fig. 2 c are the zero sequence polar plots of the utility model embodiment；
Fig. 2 d are the resultant vector figures of the utility model embodiment；
Fig. 3 is the fundamental diagram of the utility model embodiment；
Fig. 4 is the analog signal conditioner circuit diagram of the utility model embodiment.
Embodiment
The utility model is described in further detail with reference to the accompanying drawings and examples：
As shown in Figure 3, Figure 4, the current three-phase imbalance compensation device based on three level NPC includes central processing unit, AD
Signaling conversion circuit, PWM isolated drive circuits, power supply, three level NPC transverters, analog signal conditioner circuit, filter circuit,
Load current sampling unit, line voltage sampling unit, transverter output current sampling unit, DC voltage sampling unit and
IGBT temperature sampling unit and man-machine interface；Central processing unit includes CPLD and DSP, and central processing unit passes through PWM isolation drives
Circuit is connected with three level NPC transverters, and three level NPC transverters are connected by filter circuit with main circuit；Load current is adopted
One end of sample unit and line voltage sampling unit is connected with main circuit respectively, a termination of transverter output current sampling unit
Enter between filter circuit and main circuit；One end and the three level NPC changes of current of DC voltage sampling unit, IGBT temperature sampling unit
Device connects；Load current sampling unit, line voltage sampling unit, transverter output current sampling unit, DC voltage sampling
The other end of unit and IGBT temperature sampling unit is connected by analog signal conditioner circuit with AD signaling conversion circuits, AD letters
Number change-over circuit is connected with central processing unit, and power supply, man-machine interface are connected with central processing unit.
The DSP of central processing unit using 32 floating-point microprocessor TMS320F28335 of TI companies as main control chip,
TMS320F28335 is under the jurisdiction of DelfinoMCU series of products members, and running frequency may be up to 150MHz, is for requiring strict
Control highly integrated, the high performance solution of application；Control system is aided with the MAXII products of altera corp, CPLD models
For EPM1270 chips, the logical process of some data signals is substantially carried out, and dsp chip completes sampled signal processing, control meter
The major functions such as calculation, protection and pwm signal output.
The input voltage of power supply is 220V, and output voltage is+5V, ± 15V ,+24V.+ 5V mainly supplies the core core such as DSP
Piece uses, and some chips such as ± 15V supply amplifiers use, and+24V mainly supplies touch-screen use.
The effect of PWM isolated drive circuits is：CPLD+DSP produces pwm signal after calculation process, by outside amplification electricity
Road amplified signal, then the PWM drive signal with driving force is formed to drive main power circuit by isolated drive circuit
Three level NPC transverters.The PWM ripples that DSP is sent out are converted to suitable level by PWM isolated drive circuits.Meanwhile in order to ensure
Circuit safety is reliable, it is necessary to carries out electrical isolation to drive signal, conventional isolation method has light-coupled isolation and transformer isolation.
The utility model uses the 2SP0115T drive modules of Concept companies.IGBT temperature sampling unit first passes through bleeder circuit will
The change in resistance of thermistor is converted to the change of voltage, is then sent through analog signal conditioner circuit and carries out level conversion, then send
Enter AD signaling conversion circuits to be AD converted, be finally sent into DSP processing.
The major function of analog signal conditioner circuit is that the voltage and current signal condition that will be sampled is changed to AD signals
In the acceptable level range of circuit, it includes a scaling circuit and a filter circuit.Then signal is conveyed
To protection circuit, hysteresis comparator can be used for the level energizing signal of overvoltage and over-current hardware protection in protection circuit.
DC voltage sampling unit and line voltage sampling unit select voltage Hall, can change primary side voltage signal
For the small voltage signal of secondary side.
Transverter output current sampling unit selects current Hall and sampling resistor, can be converted to primary side current signal
The low current signal of secondary side, current signal is then converted into voltage signal using sampling resistor.
Load current sampling unit selects current transformer and sampling resistor, and primary side current signal is converted into secondary side
Low current signal, then using sampling resistor current signal is converted into voltage signal.
Central processing unit is also connected with PWM isolated drive circuits by protection circuit.The effect of protection circuit is protection dress
Failure-free operation is put, when device output current is too high, bus capacitor total voltage is too high, upper and lower electric capacity voltage difference is excessive, power network is electric
When reduce off-flavor is often or power device temperature is too high, protection circuit produces protection signal, cuts off PWM output signal, stops three level NPC
Transverter output current.By AD signaling conversion circuit collecting devices operation information again after protection circuit is handled, in feeding
Central processor, if breaking down, protection circuit directly blocks pwm circuit signal, and fault-signal is exported to central processing unit.
Man-machine interface is connected with CPLD+DSP, and the running status, each item data mainly to whole device are shown, and
Related data can be configured by embedded integrated touch screen human-computer interface.Man-machine interface is provided with to be connected with CPLD+DSP
Serial communication interface SCI, the Serial Peripheral Interface SPI connect, communicated after convenient with control centre.
As shown in figure 1, it is three level of current three-phase imbalance compensation device of the utility model based on three level NPC
NPC main circuit topological structure figures, compared to two level converters, in three-level converter commutation process, each IGBT is only held
By the half of DC side total voltage, place capacity is improved, reduces cost, and with output current harmonics are low, electromagnetic interference
The advantages that small, efficiency high.
It is the polar plot in the utility model after symmetrical components decomposition as shown in Fig. 2 a, 2b, 2c, 2d.It is uneven for three-phase
For balance system, the system can be divided into by three independent balanced systems by symmetrical component method：Positive sequence system, negative phase-sequence system
And zero sequence system.Positive-sequence component：Three phasors are equal in magnitude, 120 ° of mutual deviation, and identical with the phase sequence of system normal operation；Negative phase-sequence system
System：Three phasors are equal in magnitude, 120 ° of mutual deviation, and opposite with the phase sequence of system normal operation；Zero sequence system：Three phasor magnitude phases
Deng mutually perhaps identical.
If Fig. 3 is the utility model towards rural power grids power system, new three level 380V applied to the load of certain taiwan area,
50kVA three-phase imbalance compensation devices.All-digitized demodulator dress of the compensation device based on three level NPC and CPLD and DSP28335
Put.The main topological parameter of the compensation device:Grid line voltage virtual value Us=380V；Mains frequency f=50Hz；DC bus capacitor C
=3000 μ F；Grid-connected reactor Lc=0.7mH；DC capacitor voltage reference value Vdc=740V；Output-current rating Ic=
75A。
The present apparatus uses IGBT device to form transverter of the main topology for three level NPC, when producing compensation electric current, mainly
Worked as inverter.Wherein, each bridge arm of three-phase has 4 switching tubes (IGBT), and two booster diodes.Wherein each bridge
Two switching tubes of arm highest and lowest are equivalent to upper and lower switching tube in two level circuits, and two switching tubes among bridge arm
Neutral-point-clamped circuit is formed with two booster diodes.Usa, Usb, Usc are the three-phase voltages of AC network, Ica, Icb, Icc
For the three-phase current of equipment output, load and loaded for asymmetrical three-phase.Current transformer DC voltage is Udc, by two groups of electric capacity strings
Connection forms, and N points position capacitor voltage equalizing midpoint, is connected with the booster diode of each bridge arm.When the voltage on two electric capacity is equal,
Main switch bears Udc/2.Illustrate structure of the current transformer per phase bridge arm by taking A phases as an example, A phase bridge arms have four IGBT S1, S2,
S3, S4, and two clamp diodes D1, D2.
Transverter based on three level NPC technologies has obviously advantage, switching loss compared to two level converters
More small frequency is higher, and output current harmonics content is lower, and efficiency high, and can use the IGBT of more low-voltage-grade,
It is a kind of more safe and reliable, compensation device that compensation precision is higher, automatization level is higher, and in regulation three-phase imbalance
When smooth adjustment whole process, will not cause have a power failure the problem of.
Operation principle of the present utility model is：Voltage, the electric current of three-phase in sampling unit detection load, by analog signal
After modulate circuit carries out amplifier conditioning respectively, sample conversion is carried out by the AD sampling A/D chips AD7607 of AD signaling conversion circuits, it is defeated
Go out data signal to CPLD+DSP processing, negative phase-sequence and zero-sequence current in threephase load is calculated in CPLD+DSP, then
, size opposite compensation electric current identical with negative phase-sequence and zero-sequence current phase in load, compensation are produced by PWM isolated drive circuits
Electric current is cancelled out each other with the negative phase-sequence in load and zero-sequence current, is finally reached the purpose of compensation system three-phase balance.
Preferred embodiment of the present utility model is the foregoing is only, it is all at this not to limit the utility model
All any modification, equivalent and improvement made within the spirit and principle of utility model etc., should be included in the utility model
Protection domain within.
Claims (8)
- A kind of 1. current three-phase imbalance compensation device based on three level NPC, it is characterised in that：Including central processing unit, AD Signaling conversion circuit, PWM isolated drive circuits, power supply, three level NPC transverters, analog signal conditioner circuit, filter circuit, Load current sampling unit, line voltage sampling unit, transverter output current sampling unit, DC voltage sampling unit and IGBT temperature sampling unit；Central processing unit includes CPLD and DSP, and central processing unit is connected by PWM isolated drive circuits and three level NPC transverters Connect, three level NPC transverters are connected by filter circuit with main circuit；Power supply is connected with central processing unit；One end of load current sampling unit and line voltage sampling unit is connected with main circuit respectively, and transverter output current is adopted Between one end access filter circuit and main circuit of sample unit；One end of DC voltage sampling unit, IGBT temperature sampling unit It is connected with three level NPC transverters；Load current sampling unit, line voltage sampling unit, the sampling of transverter output current are single The other end of member, DC voltage sampling unit and IGBT temperature sampling unit is turned by analog signal conditioner circuit and AD signals Circuit connection is changed, AD signaling conversion circuits are connected with central processing unit.
- 2. the current three-phase imbalance compensation device according to claim 1 based on three level NPC, it is characterised in that：Also Including protection circuit, central processing unit is also connected with analog signal conditioner circuit by protection circuit.
- 3. the current three-phase imbalance compensation device according to claim 1 or 2 based on three level NPC, it is characterised in that： Also include man-machine interface, man-machine interface is connected with central processing unit.
- 4. the current three-phase imbalance compensation device according to claim 3 based on three level NPC, it is characterised in that：In The CPLD of central processor is EPM1270, DSP TMS320F28335.
- 5. the current three-phase imbalance compensation device according to claim 4 based on three level NPC, it is characterised in that：Directly Stream voltage sampling unit, line voltage sampling unit include voltage Hall.
- 6. the current three-phase imbalance compensation device according to claim 5 based on three level NPC, it is characterised in that：Change Stream device output current sampling unit includes current Hall and sampling resistor.
- 7. the current three-phase imbalance compensation device according to claim 6 based on three level NPC, it is characterised in that：It is negative Carrying current sampling unit includes current transformer and sampling resistor.
- 8. the current three-phase imbalance compensation device according to claim 7 based on three level NPC, it is characterised in that：People Machine interface is provided with serial communication interface SCI, the Serial Peripheral Interface SPI being connected with CPLD+DSP.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201720632856.XU CN206807019U (en) | 2017-06-02 | 2017-06-02 | Current three-phase imbalance compensation device based on three level NPC |
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| CN201720632856.XU CN206807019U (en) | 2017-06-02 | 2017-06-02 | Current three-phase imbalance compensation device based on three level NPC |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108667333A (en) * | 2018-04-04 | 2018-10-16 | 广东科学技术职业学院 | A kind of bidirectional converter system |
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- 2017-06-02 CN CN201720632856.XU patent/CN206807019U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108667333A (en) * | 2018-04-04 | 2018-10-16 | 广东科学技术职业学院 | A kind of bidirectional converter system |
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| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20171226 Termination date: 20190602 |
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| CF01 | Termination of patent right due to non-payment of annual fee |