CN110048631A - A kind of three-phase four-wire system gird-connected inverter method for suppressing neutral current - Google Patents

A kind of three-phase four-wire system gird-connected inverter method for suppressing neutral current Download PDF

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CN110048631A
CN110048631A CN201910224285.XA CN201910224285A CN110048631A CN 110048631 A CN110048631 A CN 110048631A CN 201910224285 A CN201910224285 A CN 201910224285A CN 110048631 A CN110048631 A CN 110048631A
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phase
current
gird
wire system
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CN110048631B (en
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何晋伟
刘宇
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Tianjin University
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Tianjin University
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    • H02J3/382—
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The present invention discloses a kind of three-phase four-wire system gird-connected inverter method for suppressing neutral current, which includes inversion unit and exchange the exchange output filter circuit of side connection with inversion unit, and exchange output filter circuit uses the filter circuit construction of LLCCL.Two bulky capacitor series connection, are connected in parallel on DC bus side, midpoint is as N line.Control method are as follows: directly inverter output current is controlled, is reference with A phase carrier wave, successively by 2 π/3 of carrier phase of B, C phase, 4 π/3 can effectively inhibit current in middle wire high fdrequency component, and power network current can reach Grid-connection standards.The control method is simple, practical value with higher.

Description

A kind of three-phase four-wire system gird-connected inverter method for suppressing neutral current
Technical field
The present invention relates to three-phase four-wire system parallel network reverse fields, and in particular to a kind of three-phase four based on alternate phase-shifting carrier wave The method that line inverter current in middle wire inhibits.
Background technique
New-energy grid-connected technology has been used widely at present, and three-phase four-wire system gird-connected inverter is as generating electricity by way of merging two or more grid systems The key component of system also has been greatly developed.But when using split capacitor as four bridge legs, current in middle wire is larger, The service life of DC bus capacitor can be reduced, and higher harmonic components are big in current in middle wire, there is noise jamming, influence equipment Normal use.
Summary of the invention
Purpose of the invention is to overcome the shortcomings in the prior art, provides in a kind of three-phase four-wire system gird-connected inverter Line current suppressing method, three-phase four-wire system gird-connected inverter directly control inverter output current, are referred to by controller Signal, using A phase as reference, successively by 2 π/3 of carrier phase of B, C phase, 4 π/3 can effectively inhibit current in middle wire high fdrequency component, And power network current can reach Grid-connection standards.The control method is simple, practical value with higher.
The purpose of the present invention is what is be achieved through the following technical solutions:
A kind of three-phase four-wire system gird-connected inverter method for suppressing neutral current, comprising the following steps:
(1) sample circuit of three-phase four-wire system gird-connected inverter is to three-phase four-wire system network voltage, inverter output current It is sampled, three-phase power grid voltage VAN、VBN、VCN, inverter output current IA、IB、IC；
(2) three-phase power grid voltage for obtaining sampling, obtains electric network voltage phase θ by phase-locked loop pll, three-phase current Reference amplitude is Iref, to obtain the reference current of three-phase four-wire system gird-connected inverter:
IAref=Irefsinθ (1-1)
IBref=Irefsin(θ-2π/3) (1-2)
ICref=Irefsin(θ+2π/3) (1-3)
(3) obtained reference current is compared respectively with sample rate current, and calculates their difference:
IA_error=IAref-IA (1-4)
IB_error=IBref-IB (1-5)
IC_error=ICref-IC (1-6)
Using the difference being calculated as the input of quasi- PR controller transfer function G (s), and plus the power grid of each phase electricity Pressure, obtains the reference of inverter output voltage:
VAref=G (s) IA_error+VAN (1-7)
VBref=G (s) IB_error+VBN (1-8)
VCref=G (s) IB_error+VCN (1-9)
The expression formula of quasi- PR controller transfer function:
Wherein kpSubject to PR controller proportionality coefficient, kiSubject to PR controller integral proportionality coefficient, wcSubject to PR control The bandwidth of device, s are Laplace transform operator；
It (4) is reference with A phase carrier wave, successively by 2 π/3 of carrier phase of B, C phase, 4 π/3 can inhibit current in middle wire at this time High fdrequency component, the driving signal of gird-connected inverter is generated in conjunction with step (2) and (3), therefore obtain inverter output voltage.
Compared with prior art, the beneficial effects brought by the technical solution of the present invention are as follows:
1. the present invention, which is compared using alternate phase-shifting carrier wave technology with conventional method, can significantly inhibit current in middle wire, and The quality for the grid-connected current that do not have an impact.
2. conventional three-phase four-wire system control method of grid-connected inverter, Three Phase Carrier Based is same carrier wave, without phase angle difference.It should Method obtains reference signal by controller, using A phase as reference, successively by carrier phase 2 π/3,4 π/3, Ke Yiyou of B, C phase Effect inhibits current in middle wire high fdrequency component, and power network current can reach Grid-connection standards；It realizes that simply effect is obvious, has very high Use value.
Detailed description of the invention
The topological structure of three-phase four-wire system gird-connected inverter in Fig. 1 embodiment of the present invention.
Fig. 2 three-phase four-wire system gird-connected inverter phase-shifting carrier wave schematic diagram.
Fig. 3 is the simulation waveform of current in middle wire, power network current.
Specific embodiment
The specific embodiment of the alternate phase-shifting carrier wave of three-phase four-wire system of the invention is described with reference to the accompanying drawing, with Just those skilled in the art more fully understands the present invention.
Fig. 1 is the circuit diagram of the specific embodiment of the invention.As shown in Figure 1, three-phase four-wire system gird-connected inverter uses three Phase full-bridge topology is as inverter circuit, and each full-bridge is by six power switch tubes, in the present embodiment for backward dioded IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) composition, exchange output filtered electrical Road uses the filter circuit construction of LLCCL, then is connected to power grid, the leakage of the middle line inductance indication transformer of grid side by filter Sense.
The present invention is the method that the alternate phase-shifting carrier wave of three-phase four-wire system gird-connected inverter inhibits current in middle wire, and basic step is such as Under:
Step 1: the sample circuit of phase four-wire system gird-connected inverter is to three-phase four-wire system network voltage, inverter output current It is sampled, three-phase power grid voltage VAN、VBN、VCN, inverter output current IA、IB、IC；
Step 2: the three-phase power grid voltage that sampling is obtained obtains electric network voltage phase θ, three-phase electricity by phase-locked loop pll The reference amplitude of stream is Iref, to obtain the reference current of three-phase four-wire system gird-connected inverter:
IAref=Irefsinθ (1)
IBref=Irefsin(θ-2π/3) (2)
ICref=Irefsin(θ+2π/3) (3)
Step 3: obtained reference current is compared respectively with sample rate current, and calculates their difference:
IA_error=IAref-IA (4)
IB_error=IBref-IB (5)
IC_error=ICref-IC (6)
Using the difference being calculated as the input of quasi- PR controller G (s), and the network voltage of each phase is added, obtained The reference of inverter output voltage:
The expression formula of quasi- PR controller:
Wherein kpSubject to PR controller proportionality coefficient, kiSubject to PR controller integral proportionality coefficient, wcSubject to PR control The bandwidth of device, s are Laplace transform operator；
Step 4: being reference with A phase carrier wave, successively by 2 π/3 of carrier phase of B, C phase, 4 π/3 can inhibit middle line at this time The high fdrequency component of electric current generates the driving signal of gird-connected inverter in conjunction with step (2) and (3), therefore obtains inverter output electricity Pressure.
Step 5: simulation model as shown in Figure 1 is built with Matlab/Simulink, to inverter control proposed by the present invention Method processed is verified.
If Fig. 2 is phase-shifting carrier wave schematic diagram, using A phase as reference, successively by 2 π/3 of carrier phase of B, C phase, 4 π/3, and Inverter output voltage is obtained according to driving signal.
As shown in figure 3, not carrying out phase-shifting carrier wave before 0.15s；Start phase-shifting carrier wave after 0.15, i.e. after 0.15s Using control method of the present invention.It can be seen that after applying the present invention by the current in middle wire of Fig. 3, under square one, in inverter Line current is reduced to 4.60A by 12.64A, and grid-connected current THD is reduced to 4.01% by 5.31%.By comparison it can be seen that originally Invention can be very good to inhibit inverter side current in middle wire, and grid-connected current reaches Grid-connection standards.
To sum up: the present invention is the method that the alternate phase-shifting carrier wave of three-phase four-wire system gird-connected inverter inhibits current in middle wire, can be with Three-phase four-wire system inverter current in middle wire is effectively reduced, and grid-connected current is made to reach Grid-connection standards.Control proposed by the present invention Strategy processed can reduce current in middle wire, improve capacitor service life, be a kind of inverter inhibition current in middle wire method being worthy to be popularized.
The present invention is not limited to embodiments described above.Above the description of specific embodiment is intended to describe and say Bright technical solution of the present invention, the above mentioned embodiment is only schematical, is not restrictive.This is not being departed from In the case of invention objective and scope of the claimed protection, those skilled in the art may be used also under the inspiration of the present invention The specific transformation of many forms is made, within these are all belonged to the scope of protection of the present invention.

Claims (1)

1. a kind of three-phase four-wire system gird-connected inverter method for suppressing neutral current, which comprises the following steps:
(1) sample circuit of three-phase four-wire system gird-connected inverter carries out three-phase four-wire system network voltage, inverter output current Sampling, three-phase power grid voltage VAN、VBN、VCN, inverter output current IA、IB、IC；
(2) three-phase power grid voltage for obtaining sampling, obtains electric network voltage phase θ, the reference of three-phase current by phase-locked loop pll Amplitude is Iref, to obtain the reference current of three-phase four-wire system gird-connected inverter:
IAref=Irefsinθ (1-1)
IBref=Iref sin(θ-2π/3) (1-2)
ICref=Iref sin(θ+2π/3) (1-3)
(3) obtained reference current is compared respectively with sample rate current, and calculates their difference:
IA_error=IAref-IA (1-4)
IB_error=IBref-IB (1-5)
IC_error=ICref-IC (1-6)
Using the difference being calculated as the input of quasi- PR controller G (s), and the network voltage of each phase is added, obtains inversion The reference of device output voltage:
VAref=G (s) IA_error+VAN (1-7)
VBref=G (s) IB_error+VBN (1-8)
VCref=G (s) IB_error+VCN (1-9)
The expression formula of quasi- PR controller:
It (4) is reference with A phase carrier wave, successively by 2 π/3 of carrier phase of B, C phase, 4 π/3 can inhibit the height of current in middle wire at this time Frequency component generates the driving signal of gird-connected inverter in conjunction with step (2) and (3), therefore obtains inverter output voltage.
CN201910224285.XA 2019-03-22 2019-03-22 Neutral current suppression method for three-phase four-wire grid-connected inverter Active CN110048631B (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110955220A (en) * 2019-11-01 2020-04-03 郑州嘉晨电器有限公司 Self-checking method and system for AC motor controller
CN116526883A (en) * 2023-05-16 2023-08-01 江苏科曜能源科技有限公司 Three-phase three-level four-bridge arm energy storage inverter and inverter system

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10164886A (en) * 1996-11-25 1998-06-19 Toshiba Corp Inverter apparatus
CN102340257A (en) * 2011-09-02 2012-02-01 南京航空航天大学 Double-current loop control method of LCL (Inductor Capacitor Inductor) filtering grid-connected inverter
CN102709951A (en) * 2012-05-26 2012-10-03 深圳市中兴昆腾有限公司 Control system and control method of three-phase independent control grid inversion
CN104810859A (en) * 2015-05-27 2015-07-29 哈尔滨工业大学 Self-adaption quasi-PRD control method for photovoltaic grid-connected inverter
CN105515359A (en) * 2016-01-21 2016-04-20 广东明阳龙源电力电子有限公司 Method for restraining modular multilevel converter (MMC) valve group loop current based on quasi proportional resonant (PR) control
CN107994797A (en) * 2017-12-11 2018-05-04 福州大学 Control method is suppressed based on quasi-resonance PR and the inverter loop current of constant reference voltage

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10164886A (en) * 1996-11-25 1998-06-19 Toshiba Corp Inverter apparatus
CN102340257A (en) * 2011-09-02 2012-02-01 南京航空航天大学 Double-current loop control method of LCL (Inductor Capacitor Inductor) filtering grid-connected inverter
CN102709951A (en) * 2012-05-26 2012-10-03 深圳市中兴昆腾有限公司 Control system and control method of three-phase independent control grid inversion
CN104810859A (en) * 2015-05-27 2015-07-29 哈尔滨工业大学 Self-adaption quasi-PRD control method for photovoltaic grid-connected inverter
CN105515359A (en) * 2016-01-21 2016-04-20 广东明阳龙源电力电子有限公司 Method for restraining modular multilevel converter (MMC) valve group loop current based on quasi proportional resonant (PR) control
CN107994797A (en) * 2017-12-11 2018-05-04 福州大学 Control method is suppressed based on quasi-resonance PR and the inverter loop current of constant reference voltage

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110955220A (en) * 2019-11-01 2020-04-03 郑州嘉晨电器有限公司 Self-checking method and system for AC motor controller
CN110955220B (en) * 2019-11-01 2021-05-11 郑州嘉晨电器有限公司 Self-checking method and system for AC motor controller
CN116526883A (en) * 2023-05-16 2023-08-01 江苏科曜能源科技有限公司 Three-phase three-level four-bridge arm energy storage inverter and inverter system

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