CN104300822A - Method for controlling single-phase non-isolated photovoltaic inverter with follow current clamping switch - Google Patents

Method for controlling single-phase non-isolated photovoltaic inverter with follow current clamping switch Download PDF

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Publication number
CN104300822A
CN104300822A CN201410501343.6A CN201410501343A CN104300822A CN 104300822 A CN104300822 A CN 104300822A CN 201410501343 A CN201410501343 A CN 201410501343A CN 104300822 A CN104300822 A CN 104300822A
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China
Prior art keywords
switching tube
source control
control waveform
inverter
grid source
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CN201410501343.6A
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Inventor
马海啸
叶海云
袁颖
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Nanjing Post and Telecommunication University
Nanjing University of Posts and Telecommunications
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Nanjing Post and Telecommunication University
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Priority to CN201410501343.6A priority Critical patent/CN104300822A/en
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48Conversion 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
    • H02M7/483Converters with outputs that each can have more than two voltages levels
    • H02M7/487Neutral point clamped inverters
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48Conversion 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
    • H02M7/53Conversion 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
    • H02M7/537Conversion 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
    • H02M7/5387Conversion 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
    • H02M7/53871Conversion 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 with automatic control of output voltage or current
    • H02M7/53873Conversion 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 with automatic control of output voltage or current with digital control
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy
    • Y02E10/56Power conversion systems, e.g. maximum power point trackers

Abstract

The invention provides a method for controlling a single-phase non-isolated photovoltaic inverter with a follow current clamping switch. The method for controlling the single-phase non-isolated photovoltaic inverter with the follow current clamping switch comprises the steps that two-section control is conducted on switch tubes in the inverter; the gate source control waveform of the first switch tube is made to the same as that of the fourth switch tube, wherein the gate source control waveforms are SPWM waveforms in the half positive cycle during which current is output by the inverter, and the gate source control waveforms are zero waveforms in the half negative cycle during which current is output by the inverter; the gate source control waveform of the second switch tube is made the same as that of the third switch tube, wherein the gate source control waveforms are zero waveforms in the half positive cycle during which current is output by the inverter, and the gate source control waveforms are SPWM waveforms in the half negative cycle during which current is output by the inverter; the gate source control waveform of the fifth switch tube and the gate source control waveform of the sixth switch tube are made to be complementary with the gate source control waveform of the first switch tube and the gate source control waveform of the fourth switch tube in the half positive cycle during which current is output by the inverter and be complementary with the gate source control waveform of the second switch tube and the gate source control waveform of the third switch tube in the half negative cycle during which current is output by the inverter. By the adoption of the method for controlling the single-phase non-isolated photovoltaic inverter with the follow current clamping switch, the conversion efficiency of the non-isolated photovoltaic inverter can be improved, and the common-mode characteristic of the non-isolated photovoltaic inverter is improved.

Description

The control method of the single-phase non-isolated photovoltaic DC-to-AC converter with afterflow clamp switch
Technical field
The present invention relates to power electronics DC-AC conversion technical field, in particular to a kind of control method of the single-phase non-isolated photovoltaic DC-to-AC converter with afterflow clamp switch, be applicable to photovoltaic generation occasion.
Background technology
Photovoltaic combining inverter requires that efficiency is high, cost is low, can bear photovoltaic cell output voltage and to fluctuate large harmful effect, and it exchanges to export and also will meet the higher quality of power supply.
Whether isolated form and non-isolation type can be divided into isolating transformer according to inverter.Isolated form photovoltaic DC-to-AC converter achieves the electrical isolation of electrical network and cell panel, and ensured the person and device security, but its volume is large, price is high, and system changeover efficiency is lower.Non-isolated photovoltaic DC-to-AC converter structure containing transformer, does not have the many advantages such as efficiency is high, volume is little, lightweight, cost is low.
At present, the peak efficiency of non-isolated photovoltaic inverter system can reach more than 98%.But removing of transformer makes to there is electrical connection between input and output, due to the existence of cell panel direct-to-ground capacitance, can produce common mode leakage current, increase system electromagnetic interference, affect the quality of inverter current during inverter work, the harm person and device security.
In order to ensure the person and device security, leakage current must be suppressed in certain scope.According to German DIN VDE 0126-1-1 standard, when Ground leakage current instantaneous value is greater than 300mA, photovoltaic parallel in system must disconnect with electrical network in 0.3s.Therefore, determining under the prerequisite without common mode leakage current, improving the efficiency of photovoltaic DC-to-AC converter as much as possible, reducing the problem in urgent need to solve that device cost becomes current photovoltaic DC-to-AC converter.
Summary of the invention
The object of the invention is the control method providing a kind of single-phase non-isolated photovoltaic DC-to-AC converter with afterflow clamp switch, is intended to eliminate common mode leakage current, improves inverter common mode characteristic, improves the conversion efficiency of inverter.
Above-mentioned purpose of the present invention is realized by the technical characteristic of independent claims, and dependent claims develops the technical characteristic of independent claims with alternative or favourable mode.
For reaching above-mentioned purpose, technical scheme of the present invention is as follows:
A control method for single-phase non-isolated photovoltaic DC-to-AC converter with afterflow clamp switch, the single-phase non-isolated photovoltaic DC-to-AC converter of this band afterflow clamp switch comprises: a single-phase full-bridge inverter, a clamping capacitance group, an afterflow clamp switch, lCLfilter circuit and a resistance, wherein:
Described afterflow clamp switch is made up of a single-phase uncontrollable rectifier bridge and two switching tubes;
Described clamping capacitance group is made up of two input capacitances;
Described single-phase full-bridge inverter is made up of four switching tubes;
Described single-phase uncontrollable rectifier bridge is made up of four rectifier diodes;
Described lCLfilter circuit is by the first filter inductance ,second filter inductance and filter capacitor composition;
Described single-phase full-bridge inverter, clamping capacitance group, afterflow clamp switch, connection between LCL filter circuit and resistance are as follows:
The drain electrode of the positive pole of described first input capacitance, the first switching tube, the 3rd switching tube is connected with the positive pole of a solar cell respectively;
The source electrode of the negative pole of described second input capacitance, second switch pipe, the 4th switching tube is connected with the negative pole of a solar cell respectively;
The source electrode of described first switching tube is connected with the drain electrode of second switch pipe; The source electrode of the 3rd switching tube is connected with the drain electrode of the 4th switching tube;
Inverter ac side adopts aforesaid four rectifier diodes to form single-phase uncontrollable rectifier bridge, wherein the first rectifier diode and the second rectifier diode common cathode, 3rd rectifier diode and the 4th rectifier diode common anode pole, the anode of the first rectifier diode is connected with the negative electrode of the 3rd rectifier diode, and the anode of the second rectifier diode is connected with the negative electrode of the 4th rectifier diode;
The source electrode of the first switching tube and the tie point of the drain electrode of second switch pipe are connected with one end of the first filter inductance with the anode of the first rectifier diode, the negative electrode of the 3rd rectifier diode respectively; The other end of the first filter inductance is connected with one end of resistance with one end of filter capacitor respectively;
The source electrode of the 3rd switching tube is connected with one end of the second filter inductance with the anode of the second rectifier diode, the negative electrode of the 4th rectifier diode respectively with the tie point of the drain electrode of the 4th switching tube; The other end of the second filter inductance is connected with the other end of resistance with the other end of filter capacitor respectively;
The drain electrode of the 5th switching tube is connected with the common cathode of single-phase uncontrollable rectifier bridge, and its source electrode is connected with the negative pole of the first input capacitance, the positive pole of the second input capacitance;
The drain electrode of the 6th switching tube is connected with the positive pole of the negative pole of the first input capacitance, the second input capacitance, and its source electrode is extremely connected with the common anode of single-phase uncontrollable rectifier bridge;
To the control method of the single-phase non-isolated photovoltaic DC-to-AC converter of described band afterflow clamp switch, it comprises:
1) make the grid source control waveform of aforementioned first switching tube identical with the grid source control waveform of the 4th switching tube, and grid source control waveform inverter output current positive half period be SPWM waveform, inverter output current negative half-cycle is zero;
2) make the grid source control waveform of second switch pipe identical with the grid source control waveform of the 3rd switching tube, and grid source control waveform inverter output current positive half period be zero, inverter output current negative half-cycle is SPWM waveform; And
3) make the grid source control waveform of the 5th switching tube and the 6th switching tube the grid source control waveform of inverter output current positive half period and the first switching tube and the grid source control waveform of the 4th switching tube complementary, in grid source control waveform and the 3rd switching tube grid source control waveform complementation of inverter output current negative half-cycle and second switch pipe.
From the above technical solution of the present invention shows that, beneficial effect of the present invention is: control method of the present invention combines the circuit topological structure of the single-phase non-isolated photovoltaic DC-to-AC converter of band afterflow clamp switch, the control method proposed realizes the control to inverter, solve non-isolated photovoltaic DC-to-AC converter and can not eliminate the technical problems such as common mode leakage current, conversion efficiency be low completely, effectively can improve the conversion efficiency of non-isolated photovoltaic DC-to-AC converter, improve the common mode characteristic of non-isolated photovoltaic DC-to-AC converter, there is significant real world applications and engineer applied value.
Accompanying drawing explanation
Fig. 1 is the electrical block diagram of the single-phase non-isolated photovoltaic DC-to-AC converter of an embodiment of the present invention band afterflow clamp switch.
Fig. 2 is the generation schematic diagram of control waveform in the control method of the single-phase non-isolated photovoltaic DC-to-AC converter of Fig. 1 example belt afterflow clamp switch.
Fig. 3 a-3d is the mode schematic diagram of the single-phase non-isolated photovoltaic DC-to-AC converter of Fig. 1 example belt afterflow clamp switch.
Embodiment
In order to more understand technology contents of the present invention, institute's accompanying drawings is coordinated to be described as follows especially exemplified by specific embodiment.
As shown in Figure 1, according to preferred embodiment of the present invention, a kind of single-phase non-isolated photovoltaic DC-to-AC converter with afterflow clamp switch, comprising: a single-phase full-bridge inverter, a clamping capacitance group, an afterflow clamp switch, lCLfilter circuit and a resistance, wherein afterflow clamp switch by a single-phase uncontrollable rectifier bridge and two switching tubes ( s 5 , S 6) composition, clamping capacitance group by two input capacitances ( c dc1, c dc2) composition, wherein:
Described single-phase full-bridge inverter by four switching tubes ( s 1 , S 2 , S 3 , S 4) composition;
Described single-phase uncontrollable rectifier bridge by four rectifier diodes ( d 1, d 2, d 3, d 4) composition;
Described lCLfilter circuit is by the first filter inductance l f1 , the second filter inductance l f2 and filter capacitor c f composition;
Described single-phase full-bridge inverter, clamping capacitance group, afterflow clamp switch, lCLconnection between filter circuit and resistance is as follows:
Described first input capacitance c dc1positive pole, the first switching tube s 1, the 3rd switching tube s 3drain electrode respectively with a solar cell u pVpositive pole be connected;
Described second input capacitance c dc2negative pole, second switch pipe s 2, the 4th switching tube s 4source electrode respectively with a solar cell u pVnegative pole be connected;
Described first switching tube s 1source electrode and second switch pipe s 2drain electrode be connected; 3rd switching tube s 3source electrode and the 4th switching tube s 4drain electrode be connected;
Aforesaid four rectifier diodes of inverter ac side employing ( d 1, d 2, d 3, d 4) form single-phase uncontrollable rectifier bridge, wherein the first rectifier diode d 1with the second rectifier diode d 2common cathode, the 3rd rectifier diode d 3with the 4th rectifier diode d 4common anode pole, the first rectifier diode d 1anode and the 3rd rectifier diode d 3negative electrode be connected, the second rectifier diode d 2anode and the 4th rectifier diode d 4negative electrode be connected;
First switching tube s 1source electrode and second switch pipe s 2drain electrode tie point A respectively with the first rectifier diode d 1anode, the 3rd rectifier diode d 3negative electrode and the first filter inductance l f1 one end be connected; First filter inductance l f1 the other end respectively with filter capacitor c f one end and resistance rone end be connected;
3rd switching tube s 3source electrode and the 4th switching tube s 4drain electrode tie point B respectively with the second rectifier diode d 2anode, the 4th rectifier diode d 4negative electrode and the second filter inductance l f2 one end be connected; Second filter inductance l f2 the other end respectively with filter capacitor c f the other end and resistance rthe other end be connected;
5th switching tube s 5drain electrode be connected with the common cathode of single-phase uncontrollable rectifier bridge, its source electrode and the first input capacitance c dc1negative pole, the second input capacitance c dc2positive pole be connected;
6th switching tube s 6drain electrode and the first input capacitance c dc1negative pole, the second input capacitance c dc2positive pole be connected, its source electrode is extremely connected with the common anode of single-phase uncontrollable rectifier bridge.
According to of the present invention open, a kind of control method of single-phase non-isolated photovoltaic DC-to-AC converter of band afterflow clamp switch of Fig. 1 embodiment, two-part control mode is adopted to aforementioned six switching tubes, that is: to the first switching tube in the single-phase non-isolated photovoltaic DC-to-AC converter of band afterflow clamp switch s 1with the 4th switching tube s 4employing two-part controls, and namely adopt SPWM Bipolar control at inverter output current positive half period, remain shutoff at inverter output current negative half-cycle, switching tube grid source control waveform is respectively v gs1 with v gs4 ; To second switch pipe s 2with the 3rd switching tube s 3also adopt two-part to control, namely remain shutoff at inverter output current positive half period, adopt SPWM Bipolar control at inverter output current negative half-cycle, switching tube grid source control waveform is respectively v gs2 with v gs3 ; To the 5th switching tube s 5with the 6th switching tube s 6same employing two-part controls, namely at inverter output current positive half period and the first switching tube s 1with the 4th switching tube s 4the complementary conducting of control signal, at inverter output current negative half-cycle and second switch pipe s 2with the 3rd switching tube s 3the complementary conducting of control signal, switching tube grid source control waveform is respectively v gs5 with v gs6 .This control method can make switching tube s 1with s 4only be operated in positive half period, switching tube s 2with s 3only be operated in negative half-cycle, reduce devices switch loss.Afterflow clamp switch is (by rectifier bridge and switching tube s 5with s 6composition) can continuous current circuit be formed, make freewheeling period freewheel current not flow through power supply, eliminate this link of energy feedback power, improve the conversion efficiency of non-isolated photovoltaic DC-to-AC converter.
Particularly, as an illustrative embodiments, realized by following manner:
1) aforementioned first switching tube is made s 1grid source control waveform v gs1 with the 4th switching tube s 4grid source control waveform v gs4 identical, and aforementioned two grid source control waveforms v gs1 , v gs4 inverter output current positive half period be SPWM waveform, inverter output current negative half-cycle is zero;
2) second switch pipe is made s 2grid source control waveform v gs2 with the 3rd switching tube s 3grid source control waveform v gs3 identical, and aforementioned two grid source control waveforms v gs2 , v gs3 inverter output current positive half period be zero, inverter output current negative half-cycle is SPWM waveform; And
3) the 5th switching tube is made s 5 grid source control waveform v gs5 with the 6th switching tube s 6 grid source control waveform v gs6 at the grid source control waveform of inverter output current positive half period and the first switching tube v gs1 with the grid source control waveform of the 4th switching tube v gs4 complementation, at the grid source control waveform of inverter output current negative half-cycle and second switch pipe v gs2 with the 3rd switching tube grid source control waveform v gs3 complementary.
Shown in composition graphs 2, be the generation schematic diagram of control waveform, in figure, waveform is from top to bottom respectively: modulating wave v r , first via triangular carrier v c1 , the second road triangular carrier v c2 , the first switching tube s 1gate source voltage waveform v gs1 ; Second switch pipe s 2gate source voltage waveform v gs2 ; 3rd switching tube s 3gate source voltage waveform v gs3 ; 4th switching tube s 4gate source voltage waveform v gs4 ; 5th switching tube s 5gate source voltage waveform v gs5 ; 6th switching tube s 6gate source voltage waveform v gs6 .
Shown in composition graphs 1 and Fig. 2, in the present embodiment, as preferred enforcement, produce control waveform by following manner:
1) a road sinusoidal modulation wave (modulating wave shown in Fig. 2 is generated v r ) and a road triangular wave, suppose sinusoidal modulation wave v r amplitude be u r , and the amplitude of triangular wave u c be more than or equal to u r / 2;
2) aforementioned triangular wave is processed, generation two-way carrier wave ( v c1 , v c2 ); And
3) by the sinusoidal modulation wave of abovementioned steps v r respectively with first via triangular carrier v c1 with the second road triangular carrier v c2 carry out friendship to cut, produce described six switching tube (S respectively 1, s 2, s 3, s 4, s 5 , s 6 ) grid control waveform.
Preferably, aforementioned triangular wave is handled as follows, produces two-way carrier wave v c1 , v c2 :
1) triangular wave is added forward dc to be biased, bias is u c , produce first via triangular carrier v c1 ; And
2) triangular wave is first oppositely added negative sense direct current biasing again, bias is u c , produce the second road triangular carrier v c2 .
More preferably, aforementioned six switching tube (S 1, s 2, s 3, s 4, s 5 , s 6 ) the production process of grid control waveform as follows:
1) sinusoidal modulation wave abovementioned steps generated and first via triangular carrier v c1 hand over and cut generation first switching tube s 1grid source control waveform v gs1 with the 4th switching tube s 4grid source control waveform v gs4 ;
2) sinusoidal modulation wave abovementioned steps generated and the second road triangular carrier v c2 hand over to cut and produce second switch pipe s 2grid source control waveform v gs2 with the 3rd switching tube s 3grid source control waveform v gs3 ; And
3) the 5th switching tube s 5grid source control waveform v gs5 with the 6th switching tube s 6grid source control waveform v gs6 by v gs1 with v gs2 do NOR-operation to obtain.
Fig. 3 a-3d is depicted as the Mode variation schematic diagram of the non-isolated photovoltaic DC-to-AC converter of the control waveform Fig. 1 embodiment according to Fig. 2, and wherein, this non-isolated photovoltaic DC-to-AC converter can be divided into 4 kinds of operation modes within an inversion cycle, difference correspondence [ , ], [ , ], [ , ] and [ , ] four time periods.In Fig. 3 a-3d, dotted portion marks and shows in the modal graph of correspondence, corresponding parts not conducting or be in off state.Below schematically illustrate the operation principle of inverter during each operation mode:
Mode 1:
As shown in Figure 3 a, [ , ] stage, switching tube , gate source voltage be high level, , be in conducting state; Switching tube , , with gate source voltage be zero, , , with be in off state.Electric current flows out from positive source, flows through , , load, , , finally flow back to power cathode.Now v aQ= v pV, v bQ=0, therefore inverter leg mid-point voltage v aB= v pV, common-mode voltage v cm=( v aQ+ v bQ)/2=0.5 v pV.
Mode 2:
As shown in Figure 3 b, [ , ] stage, switching tube , , with gate source voltage be zero, , , with be in off state; Switching tube with gate source voltage be high level, with be in conducting state.Inductive current afterflow, electric current flows through successively l f1 , load, l f2 , d 2, , , d 3; Freewheeling period, solar panel output and electrical network disconnect.Whole freewheeling period, v aQ=0.5 v pV, v bQ=0.5 v pV, therefore inverter leg mid-point voltage v aB=0, common-mode voltage v cm=( v aQ+ v bQ)/2=0.5 v pV.
Mode 3:
As shown in Figure 3 c, [ , ] stage, switching tube , gate source voltage be high level, , be in conducting state; Switching tube , , with gate source voltage be zero, , , with be in off state.Electric current flows out from positive source, flows through , , load, , , finally flow back to power cathode.Now v aQ=0, v bQ= v pV, therefore inverter leg mid-point voltage v aB=- v pV, common-mode voltage v cm=( v aQ+ v bQ)/2=0.5 v pV.
Mode 4:
As shown in Figure 3 d, [ , ] stage, switching tube , , with gate source voltage be zero, , , with be in off state; Switching tube with gate source voltage be high level, with be in conducting state.Inductive current afterflow, electric current flows through successively l f2 , load, l f1 , d 1, , , d 4.Freewheeling period, solar panel output and electrical network disconnect.Whole freewheeling period, v aQ=0.5 v pV, v bQ=0.5 v pV, therefore inverter leg mid-point voltage v aB=0, common-mode voltage v cm=( v aQ+ v bQ)/2=0.5 v pV.
From above analytic explanation, control method of the present invention combines the circuit topological structure (adding two afterflow clamp switch pipes between the mid point and single-phase uncontrollable rectifier bridge of inverter direct current input capacitance) of the single-phase non-isolated photovoltaic DC-to-AC converter of band afterflow clamp switch, the control method proposed realizes the control to inverter, solve non-isolated photovoltaic DC-to-AC converter and can not eliminate common mode leakage current completely, the technical problems such as conversion efficiency is low, effectively can improve the conversion efficiency of non-isolated photovoltaic DC-to-AC converter, improve the common mode characteristic of non-isolated photovoltaic DC-to-AC converter, and person when using and device security can be guaranteed, there is significant real world applications and engineer applied value.
Although the present invention with preferred embodiment disclose as above, so itself and be not used to limit the present invention.Persond having ordinary knowledge in the technical field of the present invention, without departing from the spirit and scope of the present invention, when being used for a variety of modifications and variations.Therefore, protection scope of the present invention is when being as the criterion depending on those as defined in claim.

Claims (4)

1. a control method for the single-phase non-isolated photovoltaic DC-to-AC converter with afterflow clamp switch, is characterized in that, the single-phase non-isolated photovoltaic DC-to-AC converter of this band afterflow clamp switch comprises: a single-phase full-bridge inverter, a clamping capacitance group, an afterflow clamp switch, lCLfilter circuit and a resistance, wherein:
Described afterflow clamp switch by a single-phase uncontrollable rectifier bridge and two switching tubes ( s 5, s 6) composition;
Described clamping capacitance group by two input capacitances ( c dc1, c dc2) composition;
Described single-phase full-bridge inverter by four switching tubes ( s 1 , S 2 , S 3 , S 4) composition;
Described single-phase uncontrollable rectifier bridge by four rectifier diodes ( d 1, d 2, d 3, d 4) composition;
Described lCLfilter circuit by the first filter inductance ( l f1 ), the second filter inductance ( l f2 ) and filter capacitor ( c f ) composition;
Described single-phase full-bridge inverter, clamping capacitance group, afterflow clamp switch, lCLconnection between filter circuit and resistance is as follows:
Described first input capacitance ( c dc1) positive pole and described single-phase full-bridge inverter the first switching tube ( s 1), the 3rd switching tube ( s 3) drain electrode respectively with a solar cell ( u pV) positive pole be connected;
Described second input capacitance ( c dc2) negative pole and described single-phase full-bridge inverter second switch pipe ( s 2), the 4th switching tube ( s 4) source electrode respectively with described solar cell ( u pV) negative pole be connected;
Described first switching tube ( s 1) source electrode and second switch pipe ( s 2) drain electrode be connected; 3rd switching tube ( s 3) source electrode and the 4th switching tube ( s 4) drain electrode be connected;
Aforesaid four rectifier diodes of inverter ac side employing ( d 1, d 2, d 3, d 4) form single-phase uncontrollable rectifier bridge, wherein the first rectifier diode ( d 1) and the second rectifier diode ( d 2) common cathode, the 3rd rectifier diode ( d 3) and the 4th rectifier diode ( d 4) common anode pole, the first rectifier diode ( d 1) anode and the 3rd rectifier diode ( d 3) negative electrode be connected, the second rectifier diode ( d 2) anode and the 4th rectifier diode ( d 4) negative electrode be connected;
First switching tube ( s 1) source electrode and second switch pipe ( s 2) drain electrode tie point (A) respectively with the first rectifier diode ( d 1) anode, the 3rd rectifier diode ( d 3) negative electrode and the first filter inductance ( l f1 ) one end be connected; First filter inductance ( l f1 ) the other end respectively with filter capacitor ( c f ) one end and resistance ( r) one end be connected;
3rd switching tube ( s 3) source electrode and the 4th switching tube ( s 4) drain electrode tie point (B) respectively with the second rectifier diode ( d 2) anode, the 4th rectifier diode ( d 4) negative electrode and the second filter inductance ( l f2 ) one end be connected; Second filter inductance ( l f2 ) the other end respectively with filter capacitor ( c f ) the other end and resistance ( r) the other end be connected;
5th switching tube ( s 5) drain electrode be connected with the common cathode of single-phase uncontrollable rectifier bridge, its source electrode and the first input capacitance ( c dc1) negative pole, the second input capacitance ( c dc2) positive pole be connected;
6th switching tube ( s 6) drain electrode and the first input capacitance ( c dc1) negative pole, the second input capacitance ( c dc2) positive pole be connected, its source electrode is extremely connected with the common anode of single-phase uncontrollable rectifier bridge;
To the control method of the single-phase non-isolated photovoltaic DC-to-AC converter of described band afterflow clamp switch, it comprises:
1) make aforementioned first switching tube ( s 1) grid source control waveform ( v gs1 ) and the 4th switching tube ( s 4) grid source control waveform ( v gs4 ) identical, and aforementioned two grid source control waveforms ( v gs1 , v gs4 ) inverter output current positive half period be SPWM waveform, inverter output current negative half-cycle is zero;
2) make second switch pipe ( s 2) grid source control waveform ( v gs2 ) and the 3rd switching tube ( s 3) grid source control waveform ( v gs3 ) identical, and aforementioned two grid source control waveforms ( v gs2 , v gs3 ) inverter output current positive half period be zero, inverter output current negative half-cycle is SPWM waveform; And
3) make the 5th switching tube ( s 5) and the 6th switching tube ( s 6) grid source control waveform ( v gs5 , v gs6 ) inverter output current positive half period and the first switching tube grid source control waveform ( v gs1 ) and the 4th switching tube grid source control waveform ( v gs4 ) complementary, inverter output current negative half-cycle and second switch pipe grid source control waveform ( v gs2 ) and the 3rd switching tube grid source control waveform ( v gs3 ) complementary.
2. the control method of the single-phase non-isolated photovoltaic DC-to-AC converter of band afterflow clamp switch according to claim 1, is characterized in that, in aforementioned control method, produce control waveform by following manner:
1) generate a road sinusoidal modulation wave and a road triangular wave, suppose sinusoidal modulation wave ( v r ) amplitude be u r , and the amplitude of triangular wave u c be more than or equal to u r / 2;
2) aforementioned triangular wave is processed, generation two-way carrier wave ( v c1 , v c2 ); And
3) by the sinusoidal modulation wave of abovementioned steps ( v r ) respectively with first via triangular carrier ( v c1 ) and the second road triangular carrier ( v c2 ) carry out friendship section, produce described six switching tube (S respectively 1, s 2, s 3, s 4, s 5 , s 6) grid control waveform.
3. the control method of the single-phase non-isolated photovoltaic DC-to-AC converter of band afterflow clamp switch according to claim 2, is characterized in that, in abovementioned steps, is handled as follows aforementioned triangular wave, generation two-way carrier wave ( v c1 , v c2 ):
1) triangular wave is added forward dc to be biased, bias is u c , generation first via triangular carrier ( v c1 ); And
2) triangular wave is first oppositely added negative sense direct current biasing again, bias is u c , produce the second road triangular carrier ( v c2 ).
4. the control method of the single-phase non-isolated photovoltaic DC-to-AC converter of band afterflow clamp switch according to claim 2, is characterized in that, in abovementioned steps, and six switching tube (S 1, s 2, s 3, s 4, s 5 , s 6) the production process of grid control waveform as follows:
1) by abovementioned steps generate sinusoidal modulation wave and first via triangular carrier ( v c1 ) friendship section generation first switching tube ( s 1) grid source control waveform ( v gs1 ) and the 4th switching tube ( s 4) grid source control waveform ( v gs4 );
2) by abovementioned steps generate sinusoidal modulation wave and the second road triangular carrier ( v c2 ) a friendship section generation second switch pipe ( s 2) grid source control waveform ( v gs2 ) and the 3rd switching tube ( s 3) grid source control waveform ( v gs3 );
3) and, the 5th switching tube ( s 5) and the 6th switching tube ( s 6) grid source control waveform ( v gs5 , v gs6 ) by ( v gs1 ) and ( v gs2 ) do NOR-operation and obtain.
CN201410501343.6A 2014-09-26 2014-09-26 Method for controlling single-phase non-isolated photovoltaic inverter with follow current clamping switch Pending CN104300822A (en)

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