CN102291032A - Inverter - Google Patents

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Publication number
CN102291032A
CN102291032A CN2011102150334A CN201110215033A CN102291032A CN 102291032 A CN102291032 A CN 102291032A CN 2011102150334 A CN2011102150334 A CN 2011102150334A CN 201110215033 A CN201110215033 A CN 201110215033A CN 102291032 A CN102291032 A CN 102291032A
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China
Prior art keywords
switching device
inverter
diode
connects
switching
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CN2011102150334A
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Chinese (zh)
Inventor
倪华
张海明
赵为
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Sungrow Power Supply Co Ltd
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Sungrow Power Supply Co Ltd
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Priority to CN2011102150334A priority Critical patent/CN102291032A/en
Publication of CN102291032A publication Critical patent/CN102291032A/en
Pending legal-status Critical Current

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Abstract

The invention discloses an inverter, which is used for converting DC output by a DC power supply into AC. The inverter comprises six switching devices and two diodes, wherein a first switching device, a first diode and a third switching device are connected in series; a second switching device, a second diode and a fourth switching device are connected in series; the first end of a fifth switching device is connected with the second end of the first switching device and the cathode of the first diode, and the second end of the fifth switching device is connected with the anode of the second diode and the first end of the fourth switching device; the first end of a sixth switching device is connected with the second end of the second switching device and the cathode of the second diode, and the second end of the sixth switching device is connected with the anode of the first diode and the first end of the third switching device; the first ends of the first and second switching devices are connected with the positive end of the DC power supply respectively; and the second ends of the third and fourth switching devices are connected with the negative end of the DC power supply respectively. The inverter can effectively suppress common mode leakage current and improve energy conversion efficiency.

Description

A kind of inverter
Technical field
The present invention relates to the voltage transitions technical field, be specifically related to a kind of inverter.
Background technology
At present in the device of converting direct-current voltage into alternating-current voltage, in order to improve conversion efficiency as far as possible, exchanging the scheme that end can adopt transless to be incorporated into the power networks, the problem that thereupon needs to pay close attention to is DC power supply (for example solar panel) existence of parasitic capacitance and the interference of the common mode leakage current that brings over the ground, promptly, time variant voltage acted on the parasitic capacitance when action of switching device may produce high frequency, and then caused leakage current generating also may go beyond the scope.High-frequency leakage current can reduce system effectiveness, and the infringement output quality of power supply increases system's electromagnetic interference, and the person is threatened, and forms potential safety hazard, and easily causes the protective device of leakage current escape, influences the reliability of whole system.
If conventional full bridge inverter adopts bipolar modulated, can obtain stable common-mode voltage, the common mode leakage current is less, but conversion efficiency is poor, and inductive current pulsation is big, needs to adopt bigger filter inductance; If full bridge inverter adopts the one pole modulation, differential mode characteristic good then as input direct voltage utilance height, the filter inductance current pulsation is little and efficient is high receives publicity, but produces the common-mode voltage of switching frequency pulsation simultaneously, and then produces the common mode leakage current.
Can address the above problem to a certain extent though increase the leakage current absorption plant, can bring problems such as increasing cost, reduction energy conversion efficiency again.
Summary of the invention
The embodiment of the invention provides a kind of inverter at the problem that above-mentioned prior art exists, with common-mode voltage, inhibition common mode leakage current, the raising energy conversion efficiency of avoiding producing the switching frequency pulsation.
For this reason, the embodiment of the invention provides following technical scheme:
A kind of inverter is used for converting the direct current of DC power supply output to alternating current, and comprising: six switching devices and two diodes, each switching device have one first end and one second end respectively;
The first switching device S1, the first diode D1 and the 3rd switching device S3 series connection;
Second switch device S2, the second diode D2 and the 4th switching device S4 series connection;
First end of first end of the first switching device S1 and second switch device S2 connects the anode of described DC power supply respectively; Second end of second end of the 3rd switching device S3 and the 4th switching device S4 connects the negative terminal of described DC power supply respectively;
First end of the 5th switching device S5 connects second end of the first switching device S1 and the negative electrode of the first diode D1, and second end connects first end of the 4th switching device S4 and the anode of the second diode D2;
First end of the 6th switching device S6 connects second end of second switch device S2 and the negative electrode of the second diode D2, and second end connects first end of the 3rd switching device S3 and the anode of the first diode D1;
First end of first end of the 5th switching device S5 and the 6th switching device S6 is two outputs of described inverter.
Preferably, the first switching device S1, second switch device S2, the 3rd switching device S3 and the 4th switching device S4 are the switching tube of symmetry.
Preferably, the first switching device S1, second switch device S2, the 3rd switching device S3 and the 4th switching device S4 are MOSFET.
Preferably, the preceding half period in a work period, the first switching device S1 and the 3rd switching device S3 be with synchronous high-frequency pulse signal trigger action, the 6th switching device S6 conducting, and second switch device S2, the 4th switching device S4 and the 5th switching device S5 turn-off; In the later half cycle in a work period, second switch device S2 and the 4th switching device S4 be with synchronous high-frequency pulse signal trigger action, the 5th switching device S5 conducting, and the first switching device S1, the 3rd switching device S3 and the 6th switching device S6 turn-off.
Preferably, described high-frequency pulse signal is a pwm pulse signal.
Preferably, described high-frequency pulse signal is the pulse signal in the KHz scope.
Preferably, described inverter also comprises: energy-storage travelling wave tube is connected the two ends of described DC power supply.
Preferably, described energy-storage travelling wave tube is an electric capacity.
Preferably, described inverter also comprises: first inductance L 1 and second inductance L 2, first end of first inductance L 1 connects first end of the 5th switching device S5, first end of second inductance L 2 connects first end of the 6th switching device S6, and second end of second end of first inductance L 1 and second inductance L 2 is connected to the two ends of civil power or AC load.
The inverter that the embodiment of the invention provides can make continuous current circuit and DC side disconnect fully, effectively suppresses the common mode leakage current, improves energy conversion efficiency.
Description of drawings
In order to be illustrated more clearly in the embodiment of the present application or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use among the embodiment below, apparently, the accompanying drawing that describes below only is some embodiment that put down in writing among the present invention, for those of ordinary skills, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the circuit diagram of embodiment of the invention inverter;
Fig. 2 is the drive signal schematic diagram of each switching device in the embodiment of the invention inverter course of work;
Fig. 3 is an embodiment of the invention inverter at the current circuit schematic diagram during in load voltage positive half period pwm pulse triggering and conducting under the drive signal shown in Figure 2;
Fig. 4 is that embodiment of the invention inverter is at the current circuit schematic diagram when load voltage positive half period pwm pulse turn-offs under the drive signal shown in Figure 2;
Fig. 5 is an embodiment of the invention inverter at the current circuit schematic diagram during in load voltage negative half-cycle pwm pulse triggering and conducting under the drive signal shown in Figure 2;
Fig. 6 is that embodiment of the invention inverter is at the current circuit schematic diagram when load voltage negative half-cycle pwm pulse turn-offs under the drive signal shown in Figure 2.
Embodiment
In order to make those skilled in the art person understand the scheme of the embodiment of the invention better, the embodiment of the invention is described in further detail below in conjunction with drawings and embodiments.
As shown in Figure 1, be the circuit diagram of embodiment of the invention inverter.
This inverter 2 is used for converting the direct voltage of DC power supply 1 output to alternating current, offers civil power or AC load 3.
Inverter 2 comprises: six switching device S1 to S6, two diode D1, D2, each switching device have one first end and one second end respectively.Wherein:
The first switching device S1, the first diode D1 and the 3rd switching device S3 series connection;
Second switch device S2, the second diode D2 and the 4th switching device S4 series connection;
First end of the 5th switching device S5 connects second end of the first switching device S1 and the negative electrode of the first diode D1, and second end connects first end of the 4th switching device S4 and the anode of the second diode D2;
First end of the 6th switching device S6 connects second end of second switch device S2 and the negative electrode of the second diode D2, and second end connects first end of the 3rd switching device S3 and the anode of the first diode D1;
First end of first end of the 5th switching device S5 and the 6th switching device S6 is as two outputs of inverter 2.
This inverter 2 also can further comprise: be connected the energy storage device at the two ends of described DC power supply, this energy storage device can be an electric capacity, capacitor C 1 as shown in fig. 1.
As shown in Figure 1, this inverter 2 also can further comprise: two inductance L 1, L2, wherein:
First end of first inductance L 1 connects first end of the 5th switching device S5, first end of second inductance L 2 connects first end of the 6th switching device S6, and second end of second end of first inductance L 1 and second inductance L 2 is connected to the two ends of civil power or AC load.
In this embodiment, first end of first end of the first switching device S1 and second switch device S2 connects the anode of DC power supply 1 respectively; Second end of second end of the 3rd switching device S3 and the 4th switching device S4 connects the negative terminal of described DC power supply respectively.
The above-mentioned first switching device S1, second switch device S2, the 3rd switching device S3 and the 4th switching device S4 are the switching tube of symmetry, and such as MOSFET, correspondingly, first end of above-mentioned switching device is meant that the D utmost point of MOSFET, second end are meant the S utmost point of MOSFET.
Above-mentioned the 5th switching device S5 and the 6th switching device S6 can be IGBT, and correspondingly, first end of the 5th switching device S5, the 6th switching device S6 is meant collector electrode, and second end is meant emitter.
Above-mentioned DC power supply 1 can be a generator VDC, such as solar generator.
A work period of inverter shown in Figure 1 was made up of preceding half period and later half cycle, the corresponding course of work of inverter in a work period is divided into two stages, is respectively the working stage that load voltage is the working stage of timing and load voltage when negative.
In the work period, the drive signal waveform of each switching tube of inverter as shown in Figure 2, wherein, V AcVoltage signal in the expression load.
(T represents a switch periods at phase I 0~T/2, it is the load voltage signal cycle), corresponding to load voltage is the working stage of timing, the first switching device S1 and the 3rd switching device S3 are with synchronous high-frequency pulse signal trigger action, the 6th switching device S6 conducting, second switch device S2, the 4th switching device S4 and the 5th switching device S5 turn-off.
At second stage T/2~T, working stage when being negative corresponding to load voltage, second switch device S2 and the 4th switching device S4 be with synchronous high-frequency pulse signal trigger action, the 5th switching device S5 conducting, and the first switching device S1, the 3rd switching device S3 and the 6th switching device S6 turn-off.
Above-mentioned high-frequency pulse signal is a pwm pulse signal, such as being pulse signal in the KHz scope.
Be example with modulation system shown in Figure 2 below, the operation principle of embodiment of the invention inverter is elaborated.
For convenience, define following parameter below earlier:
V DcBe the output voltage of DC power supply, V AoBe the voltage that a point and O among the figure are ordered, V BoBe the voltage that b point and O among the figure are ordered, V CMBe common-mode voltage, i CMBe common mode leakage current, C CMBe DC power supply 1 the appearance value of parasitic capacitance, i.e. common mode capacitance appearance value over the ground.
(T represents a switch periods at phase I 0~T/2, it is the load voltage signal cycle), corresponding to load voltage is the working stage of timing, the first switching device S1 and the 3rd switching device S3 are with synchronous high-frequency pulse signal trigger action, the 6th switching device S6 conducting, second switch device S2, the 4th switching device S4 and the 5th switching device S5 turn-off.
As the first switching device S1, when the 3rd switching device S3 opens, because the cathode voltage of the first diode D1 is higher than anode voltage, therefore the first diode D1 keeps blocking state, does not have electric current to flow through, and current circuit is: VDC +→ S1 → L1 → load → L2 → S6 → S3 → VDC -, as shown in Figure 3.
At this moment, V Ao=V Dc, V Bo=0, the common-mode voltage of inverter is:
V CM=(V ao+V bo)/2=(V dc+0)/2=V dc/2 (1)
When the first switching device S1, the 3rd switching device S3 turn-off, because the electric current among inductance L 1 and the L2 can not suddenly change, the both end voltage of the first diode D1 is reverse, the first diode D1 transfers opening state to by blocking state, formed continuous current circuit, current circuit becomes: L1 → load → L2 → S6 → D1 → L1, as shown in Figure 4.
At this moment, V Ao=V Dc/ 2, V Bo=V Dc/ 2, the common-mode voltage of inverter is:
V CM=(V ao+V bo)/2=(V dc/2+V dc/2)/2=V dc/2 (2)
As seen, inverter is in the above-mentioned phase I, and common-mode voltage remains unchanged, and is V Dc/ 2.
At second stage T/2~T, working stage when being negative corresponding to load voltage, second switch device S2 and the 4th switching device S4 be with synchronous high-frequency pulse signal trigger action, the 5th switching device S5 conducting, and the first switching device S1, the 3rd switching device S3 and the 6th switching device S6 turn-off.
As second switch device S2, when the 4th switching device S4 opens, because the cathode voltage of the second diode D2 is higher than anode voltage, the second diode D2 keeps off state, does not have electric current to flow through, and current circuit is VDC +→ S2 → L2 → load → L1 → S5 → S4 → VDC -, as shown in Figure 5.
At this moment, V Ao=0, V Bo=V Dc, common-mode voltage is:
V CM=(V ao+V bo)/2=(0+V dc)/2=V dc/2;(3)
When second switch device S2, the 4th switching device S4 turn-off, because the electric current among inductance L 1 and the L2 can not suddenly change, the both end voltage of the second diode D2 is reverse, the second diode D2 transfers opening state to by blocking state, formed continuous current circuit, current circuit becomes: L2 → load → L1 → S5 → D2 → L2, as shown in Figure 6.
At this moment, V Ao=V Dc/ 2, V Bo=V Dc/ 2, common-mode voltage is:
V CM=(V ao+V bo)/2=(V dc/2+V dc/2)/2=V dc/2 (4)
As seen, inverter is in above-mentioned second stage, and common-mode voltage remains unchanged, and is V Dc/ 2.
By above-mentioned analysis to the inverter course of work as can be seen, common-mode voltage V CMAll the time invariable in entire work process, by common-mode voltage V CMMode ship current i together CMBetween relation (i CM=C CMDV CM/ dt) as can be known, common mode leakage current i CMBe always zero.
More than the embodiment of the invention is described in detail, used embodiment herein the present invention set forth, the explanation of above embodiment just is used for help understanding equipment of the present invention; Simultaneously, for one of ordinary skill in the art, according to thought of the present invention, the part that all can change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention.

Claims (9)

1. an inverter is used for converting the direct current of DC power supply output to alternating current, it is characterized in that comprise: six switching devices and two diodes, each switching device have one first end and one second end respectively;
First switching device (S1), first diode (D1) and the 3rd switching device (S3) series connection;
Second switch device (S2), second diode (D2) and the 4th switching device (S4) series connection;
First end of first end of first switching device (S1) and second switch device (S2) connects the anode of described DC power supply respectively; Second end of second end of the 3rd switching device (S3) and the 4th switching device (S4) connects the negative terminal of described DC power supply respectively;
First end of the 5th switching device (S5) connects second end of first switching device (S1) and the negative electrode of first diode (D1), and second end connects first end of the 4th switching device (S4) and the anode of second diode (D2);
First end of the 6th switching device (S6) connects second end of second switch device (S2) and the negative electrode of second diode (D2), and second end connects first end of the 3rd switching device (S3) and the anode of first diode (D1);
First end of first end of the 5th switching device (S5) and the 6th switching device (S6) is two outputs of described inverter.
2. inverter according to claim 1 is characterized in that, first switching device (S1), second switch device (S2), the 3rd switching device (S3) and the 4th switching device (S4) are the switching tube of symmetry.
3. inverter according to claim 2 is characterized in that, described first switching device (S1), second switch device (S2), the 3rd switching device (S3) and the 4th switching device (S4) are MOSFET.
4. according to each described inverter of claim 1 to 3, it is characterized in that, the preceding half period in a work period, first switching device (S1) and the 3rd switching device (S3) are with synchronous high-frequency pulse signal trigger action, the 6th switching device (S6) conducting, second switch device (S2), the 4th switching device (S4) and the 5th switching device (S5) turn-off; The later half cycle in a work period, second switch device (S2) and the 4th switching device (S4) are with synchronous high-frequency pulse signal trigger action, the 5th switching device (S5) conducting, first switching device (S1), the 3rd switching device (S3) and the 6th switching device (S6) turn-off.
5. inverter according to claim 4 is characterized in that, described high-frequency pulse signal is a pwm pulse signal.
6. inverter according to claim 4 is characterized in that, described high-frequency pulse signal is the pulse signal in the KHz scope.
7. inverter according to claim 1 is characterized in that, described inverter also comprises:
Energy-storage travelling wave tube is connected the two ends of described DC power supply.
8. inverter according to claim 7 is characterized in that, described energy-storage travelling wave tube is an electric capacity.
9. according to claim 7 or 8 described inverters, it is characterized in that, described inverter also comprises: first inductance (L1) and second inductance (L2), first end of first inductance (L1) connects first end of the 5th switching device (S5), first end of second inductance (L2) connects first end of the 6th switching device (S6), and second end of second end of first inductance (L1) and second inductance (L2) is connected to the two ends of civil power or AC load.
CN2011102150334A 2011-07-29 2011-07-29 Inverter Pending CN102291032A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106849722A (en) * 2017-03-29 2017-06-13 中南大学 A kind of modified HERIC single-phase inverters
CN114337207A (en) * 2021-12-16 2022-04-12 天津城建大学 Topology for multiphase stacked interleaved buck converter

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102088193A (en) * 2011-03-04 2011-06-08 东南大学 Photovoltaic synchronization grid full bridge six-switching tube inverter and control method thereof
CN102157955A (en) * 2011-02-28 2011-08-17 特变电工新疆新能源股份有限公司 Single-phase non-isolation type photovoltaic grid-connected inverter and control method
CN202353489U (en) * 2011-07-29 2012-07-25 阳光电源股份有限公司 Inverter

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Publication number Priority date Publication date Assignee Title
CN102157955A (en) * 2011-02-28 2011-08-17 特变电工新疆新能源股份有限公司 Single-phase non-isolation type photovoltaic grid-connected inverter and control method
CN102088193A (en) * 2011-03-04 2011-06-08 东南大学 Photovoltaic synchronization grid full bridge six-switching tube inverter and control method thereof
CN202353489U (en) * 2011-07-29 2012-07-25 阳光电源股份有限公司 Inverter

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106849722A (en) * 2017-03-29 2017-06-13 中南大学 A kind of modified HERIC single-phase inverters
CN114337207A (en) * 2021-12-16 2022-04-12 天津城建大学 Topology for multiphase stacked interleaved buck converter
CN114337207B (en) * 2021-12-16 2023-10-31 天津城建大学 Topology of multiphase stacked interleaved buck converter

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Application publication date: 20111221