CN102780414B - Device and method for inhibiting inrush starting current for large-power grid-connected inverter - Google Patents
Device and method for inhibiting inrush starting current for large-power grid-connected inverter Download PDFInfo
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- CN102780414B CN102780414B CN201210009985.5A CN201210009985A CN102780414B CN 102780414 B CN102780414 B CN 102780414B CN 201210009985 A CN201210009985 A CN 201210009985A CN 102780414 B CN102780414 B CN 102780414B
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Abstract
The invention discloses a digitized method for inhibiting the impulse current of a large-power grid-connected inverter. The grid-connected inverter consists of a direct-current voltage source, a three-phase inverter, a filtering inductor, a filtering capacitor and a digital current controller. When the grid-connected inverter responds a starting command, the amplitude and the phase of the three-phase mains voltage are detected; a modulating wave value is calculated according to the mains voltage; if direct-current side voltage satisfies the lowest grid-connected voltage of the inverter, an inverter alternating-current contactor is closed; the modulating wave value at the moment is used as an initial value of the output of a digital controller, and the digital controller begins to work; the grid-connected inverter achieves a steady-state value at the beginning moment; and grid-connected impulse-free can be realized without a transition process. The digitized method for inhibiting the impulse current of the big-power grid-connected inverter is suitable for PWM (pulse-width modulation)-type grid-connected inverters of various forms, grid-connected current can directly enter the steady state when grid connection is carried out at any moment, and smooth impulse-free grid connection is realized.
Description
Technical field
The present invention relates to the digitizing solution that a kind of combining inverter suppresses inrush current, belong to the field of control method of grid-connected inverter.
Background technology
Three-phase PWM type combining inverter can realize with any power factor to electrical network energy feeding, along with regenerative resource is generated electricity by way of merging two or more grid systems control technology one of focus becoming research of the development of technology, Three-phase high-power combining inverter.
Combining inverter, in actual motion, due to the existence of closed loop current FEEDBACK CONTROL, usually only controls the given value of current of current digital controller, and the initial value of output is set to 0.Due to the difference in grid-connected moment and the impact of DSP control hysteresis, there is amplitude and phase difference instantaneously grid-connected in the output voltage of combining inverter and line voltage, and equivalent circuit diagram as shown in Figure 3, can cause grid-connected moment inductance impulse current excessive.In addition, the excessive inductance that easily causes of grid-connected current is saturated, thus electric current in circuit can be made to increase sharply, and then causes protective device action, even damages switching device.
Fig. 1 and Fig. 2 is common three-phase grid-connected inverter topological circuit figure, grid-connected starting method conventional at present has several as follows: first method is by grid-connected impulse current and the relation dropping into the moment, select Best Point that combining inverter is cut electrical network, this method is one of effective ways suppressing Strategy for Single-Phase Grid-connected Inverter impulse current, but for three-phase grid-connected inverter, three-phase differs 120 °, the best time point can not be reached simultaneously, the grid-connected moment still can make at least onely there is impulse current mutually, can impact inverter and electrical network; Before second method is grid-connected relay closes, inverter is made to be in independent operation mode, by same to the output voltage of inverter and line voltage frequently with after identical amplitude, closed grid-connected switch again, this method can effectively reduce inrush current, but works at grid-connected front inverter, the waste of portion of energy can be caused, and inverter is when being transitioned into grid-connect mode by stand-alone mode, process is comparatively complicated, has the possibility producing impulse current.
Summary of the invention
The present invention is exactly the deficiency for conventional art, what propose is a kind of for suppressing the device of the inrush current of high-power combining inverter, solve the existence due to inrush current in high-power grid-connected system, to the harmful effect that switching device and electrical network cause, propose a kind of grid-connected effective ways that all can suppress impulse current at any time simultaneously.
The device of high-power combining inverter suppression inrush current of the present invention is: be configured with filter inductance successively at the AC of alternating current-direct current inverter, current sensor, AC voltage sensor, exchange slow-operating relay and AC relay, PWM unit (Pulse Width Modulation is configured with in the DC side of alternating current-direct current inverter, pulse width modulation), DSP control unit (Digital Signal Processing, Digital Signal Processing) and electric current and voltage sampling unit, also be configured with voltage measurement unit in the DC side of alternating current-direct current inverter simultaneously.
Current digital controller and period register is had in described DSP control unit.
Have three current digital controllers in described DSP control unit, three described current digital controllers control three-phase grid electric current respectively.
Further, described current digital controller is PI controller.
The method that high-power combining inverter described in utilization suppresses the device of inrush current to realize digitlization suppression is:
The first step: before inverter startup, DSP control unit blocks the pulse of PWM unit, after passing to DSP control unit under the starting command of host computer, DSP control unit is detected three-phase mains voltage, the phase place being obtained line voltage by phase-locked link and frequency, is obtained the instantaneous value of three-phase mains voltage by voltage, current sampling unit
u a(k),
u b(k),
u c(k);
Second step: according to the sampled value of three-phase mains voltage
u a(k),
u b(k),
u cthe voltage sample value V of (k) and DC side voltage of converter measuring unit
dcand the T1PR value of period register in the task manager of DSP control unit, obtain
moment three-phase mains modulating wave
,
,
value:
When three-phase mains voltage meets Grid-connection standards, DSP control unit is by the value of three-phase modulations ripple
,
,
assignment, to PWM unit, makes inverter output voltage and civil power with frequently with identical amplitude;
3rd step: the voltage measurement unit of the DC side configuration of alternating current-direct current inverter measures the voltage of alternating current-direct current inverter, when this voltage meets minimum grid-connected voltage, closed interchange slow-operating relay, time delay is after 1 second, closed AC relay is now the k+n moment, and by the modulating wave in k+n moment
,
,
assignment is to the current digital controller of DSP control unit, and this assignment is as the initial value in current digital controller k+n-1 moment simultaneously, and the current digital controller of DSP control unit is started working, and opens pwm pulse, realizes the output of grid-connected current.
Beneficial effect of the present invention is: the present invention do not increase hardware cost, do not waste energy prerequisite under, the digitizing solution suppressing high-power combining inverter inrush current is proposed, by above-mentioned control algolithm, inscribe without impacting grid-connected when can realize any, reduce even to eliminate and start the impact on switching device and electrical network of moment impact electric current, it is convenient to control, successful.
Accompanying drawing explanation
Fig. 1 is three-phase grid-connected inverter main circuit diagram
Fig. 2 is another layout circuit diagram of three-phase grid-connected inverter main circuit
Fig. 3 is the device simplified electrical circuit diagram that high-power combining inverter suppresses inrush current
Fig. 4 is that grid-connected current ring controls sketch
Fig. 5 is C phase line voltage and inductive current oscillogram when not using the present invention program
Fig. 6 is C phase line voltage during use the present invention program and inductive current oscillogram
In figure: 1, inverter; 2, filter inductance; 3, current sensor; 4, AC voltage sensor; 5, slow-operating relay is exchanged; 6, AC relay; 7, utility grid; 8, voltage electricity sampling unit; 9, DSP control unit; 10, three-phase modulations ripple; 11, PWM unit; 12, DC voltage measuring unit.
Embodiment
As Fig. 3, the device of high-power combining inverter suppression inrush current of the present invention is: be configured with filter inductance 2, current sensor 3, AC voltage sensor 4 successively at the AC of alternating current-direct current inverter 1, exchange slow-operating relay 5 and AC relay 6, exchange slow-operating relay 5 to be connected with utility grid 7, be configured with PWM unit 11, DSP control unit 9 and electric current and voltage sampling unit 8 in the DC side of alternating current-direct current inverter 1, be also configured with voltage measurement unit 12 in the DC side of alternating current-direct current inverter 1 simultaneously.
Current digital controller and period register is had in described DSP control unit 9.
Have three current digital controllers in described DSP control unit 9, three described current digital controllers control the phase in three-phase grid electric current respectively.
In system standby process, after passing to DSP control unit 9 under the starting command of host computer, DSP control unit 9 blocks PWM unit 11 pulse, detects three-phase mains voltage, by phase place and the frequency of phase-locked acquisition line voltage, obtain three-phase mains voltage magnitude by electric current and voltage sampling unit 8, if three-phase mains voltage meets Grid-connection standards, same frequently with the principle of identical amplitude according to inverter 1 output voltage and utility grid, calculate three-phase modulations ripple 10
,
,
size, by three-phase modulations ripple 10 assignment that calculates to PWM unit 11.
The computational methods of described three-phase modulations ripple 10 are: according to the sampled value of three-phase mains voltage
u a(k),
u b(k),
u cthe voltage sample value V of the DC voltage measuring unit of (k) and alternating current-direct current inverter
dcand the T1PR value of period register in the task manager of DSP control unit, can obtain
moment three-phase modulations ripple
,
,
value:
Further, the voltage measurement unit 12 of the DC side configuration of alternating current-direct current inverter measures the voltage of alternating current-direct current inverter 1, and when this voltage meets minimum grid-connected voltage, the closed slow-operating relay 5 that exchanges also will
kthe value of moment modulating wave
,
,
assignment PWM control unit, open pwm pulse, realize the output of grid-connected current, now, the current digital controller in DSP control unit 9 does not put into operation.Afterwards, every fixed cycle sampling three-phase line voltage, calculate three-phase modulations ripple assignment to PWM unit.This cycle is determined by the T1PR value of period register.
Time delay is after 1 second, and closed AC relay 6, the operation node time of current digital controller is closed AC relay 6.
As shown in Figure 4, the detailed process that grid-connected current digitial controller puts into operation is:
If the moment of putting into operation is
,
being input as of moment current digital controller
, the output of current digital controller is
, then the difference formula of current digital controller is:
K in above-mentioned formula
pfor proportionality coefficient, k
ifor integral coefficient.
Further,
the input of moment current digital controller
for the difference that electric current and the given current subtraction of current sensor 3 obtain.
Further, described given electric current refers to grid-connected sinusoidal current command value.
Three-phase modulations ripple is existed
the value in moment
,
,
assignment gives three corresponding current digital controllers simultaneously, as the initial value of current digital controller
,
,
:
Meanwhile,
moment starting current digitial controller,
through current digital controller, calculate to obtain three-phase modulations ripple by the difference formula of current digital controller
,
,
value, and using them again as the value of three-phase modulations ripple
,
,
being loaded in PWM unit, obtaining the drive singal for driving IGBT switching tube, start grid-connected current and export.
Further,
the value of later three-phase modulations ripple is calculated by the difference equation of current digital controller and determines, is no longer decided by the calculating of civil power sampled value.
Scheme of the present invention is by modulating wave and current digital controller initialize, combining inverter is made directly to enter another kind of stable state by a kind of stable state, without transient process, reduce the impulse current because voltage phase difference and difference in magnitude cause, achieve combining inverter and start moment non-impact current, can not impact switching device and electrical network.
For verifying practicality of the present invention, adopt the topological structure of three-phase six brachium pontis composite type combining inverter, at power be 500KVA model machine on test.
It is grid-connected that experiment shows that the A phase zero crossing moment starts, and BC phase has larger impulse current, and Fig. 5 is C phase inductance electric current and C phase line voltage waveform, can find out that impulse current peak value is up to 350A; Fig. 6 is C phase voltage after the inventive method process and C phase inductance current waveform, can find out that the method realizes non-impact current substantially grid-connected from oscillogram.
Claims (9)
1. the method for a high-power combining inverter suppression inrush current, for described high-power combining inverter, filter inductance, current sensor, AC voltage sensor, interchange slow-operating relay and AC relay is configured with successively at the AC of alternating current-direct current inverter, be configured with PWM unit, DSP control unit and electric current and voltage sampling unit in the DC side of alternating current-direct current inverter, be also configured with voltage measurement unit in the DC side of alternating current-direct current inverter simultaneously; It is characterized in that:
The first step: before inverter startup, DSP control unit blocks the pulse of PWM unit, after passing to DSP control unit under the starting command of host computer, DSP control unit detects three-phase mains voltage, obtained phase place and the frequency of line voltage by phase-locked link, obtained the instantaneous value U of three-phase mains voltage by electric current and voltage sampling unit
ga(k), U
gb(k), U
gc(k);
Second step: according to the sampled value u in three-phase mains voltage k moment
a(k), u
b(k), u
cthe voltage sample value V of (k) and DC side voltage of converter measuring unit
dcand the T1PR value of period register in the task manager of DSP control unit, obtain k moment three-phase mains modulating wave v
ma(k), v
mb(k), v
mcthe value of (k);
3rd step: the voltage measurement unit of the DC side configuration of alternating current-direct current inverter measures the voltage of alternating current-direct current inverter, when this voltage meets minimum grid-connected voltage, closed interchange slow-operating relay, time delay is after 1 second, closed AC relay is now the k+n moment, and by the modulating wave v in k+n moment
ma(k+n), v
mb(k+n), v
mc(k+n) assignment is to the current digital controller of DSP control unit, and this assignment is as the initial value in current digital controller k+n-1 moment simultaneously, and the current digital controller of DSP control unit is started working, and opens pwm pulse, realizes the output of grid-connected current.
2. the method for digitlization suppression as claimed in claim 1, is characterized by, and when three-phase mains voltage meets Grid-connection standards, inverter output voltage and the same frequency of civil power are with identical amplitude.
3. the method for digitlization suppression as claimed in claim 1, is characterized by, and the condition that the current digital controller of described DSP control unit is started working is closed AC relay.
4. the method for digitlization suppression as claimed in claim 1, is characterized by, when current digital controller put into operation in the k+n moment, by the value v of three-phase modulations ripple in the k+n moment
ma(k+n), v
mb(k+n), v
mc(k+n) assignment gives three corresponding current digital controllers simultaneously, as the initial value v in current digital controller k+n-1 moment
a(k+n-1), v
b(k+n-1), v
c(k+n-1).
5. the method for digitlization suppression as claimed in claim 1, it is characterized by, when current digital controller is after the k+n moment puts into operation, the output valve that the value of the three-phase modulations ripple after the k+n moment is calculated by the difference equation of current digital controller is determined, is no longer determined by the calculating of civil power sampled value.
6. the method for digitlization suppression as claimed in claim 1, it is characterized by, the difference equation of described current digital controller is:
v(k+n)＝v(k+n-1)+k
p[i
err(k+n)-i
err(k+n-1)]+k
ii
err(k+n)
Wherein: v (k+n) is k+n moment current digital controller output valve;
V (k+n-1) is k+n-1 moment current digital controller output valve;
pfor proportionality coefficient;
ifor integral coefficient
I
err(k+n) be difference that electric current and the given current subtraction of k+n moment current sensor obtain;
I
err(k+n-1) be difference that electric current and the given current subtraction of k+n-1 moment current sensor obtain.
7. the method for digitlization suppression as claimed in claim 6, it is characterized by, described given electric current refers to simple sinusoidal alternating current instruction.
8. a kind of high-power combining inverter as claimed in claim 1 suppresses the method for inrush current, and it is characterized in that there are three current digital controllers in described DSP control unit, three described current digital controllers control three-phase grid electric current respectively.
9. a kind of high-power combining inverter as claimed in claim 1 suppresses the method for inrush current, and it is characterized in that, described current digital controller is PI controller.
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| CN103312139B (en) * | 2012-03-09 | 2016-05-11 | 台达电子工业股份有限公司 | A kind of starting drive of combining inverter and control method thereof |
| CN103368199B (en) * | 2013-04-10 | 2015-03-11 | 万洲电气股份有限公司 | Parallelable large energy feedback device electricity-saving device |
| CN104300774A (en) * | 2014-09-02 | 2015-01-21 | 中国东方电气集团有限公司 | Starting device of single-phase grid-connected inverter and control method |
| CN108365628B (en) * | 2018-03-12 | 2022-01-14 | 固德威技术股份有限公司 | Three-phase photovoltaic grid-connected inverter non-impact current grid-connected control method |
| CN113078806B (en) * | 2021-05-11 | 2022-06-14 | 江苏固德威电源科技股份有限公司 | Method and device for inhibiting pull-in impact current of inverter output relay |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201490725U (en) * | 2009-09-01 | 2010-05-26 | 合肥阳光电源有限公司 | Buffer grid-connected circuit for transformer of photovoltaic grid-connected inverter |
| CN101789606A (en) * | 2010-03-12 | 2010-07-28 | 合肥阳光电源有限公司 | Boosting method for synchronization without insulating photovoltaic grid-connected inverters |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201490725U (en) * | 2009-09-01 | 2010-05-26 | 合肥阳光电源有限公司 | Buffer grid-connected circuit for transformer of photovoltaic grid-connected inverter |
| CN101789606A (en) * | 2010-03-12 | 2010-07-28 | 合肥阳光电源有限公司 | Boosting method for synchronization without insulating photovoltaic grid-connected inverters |
Non-Patent Citations (2)
| Title |
|---|
| JP特开2008-289211A 2008.11.27 * |
| 光伏发电系统软开关并网研究;袁继敏等;《电力自动化设备》;20100930;第30卷(第9期);85-88 * |
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