CN209516963U - A kind of single-phase active clamper non-isolated grid-connected inverter - Google Patents

Abstract

The utility model provides a kind of single-phase active clamper non-isolated grid-connected inverter, including eight switching tubes, two diodes and two split capacitors, two of them switching tube constitutes two-way opened and closes clamping action, common-mode voltage can be made to keep constant, and is suitable for photovoltaic generating system.The utility model circuit can in effective solution inversion link as do not use transformer and caused by common mode current leakage, simultaneously because freewheeling period electric current is not passed through body diode, therefore MOSFET element can be used, reduce the turn-off power loss as caused by tail currents when as IGBT device shutdown, and SiC diode can substitute general-purpose diode, the available good inhibition of the loss of Reverse recovery.Therefore the utility model circuit can effectively inhibit common mode leakage current, while improve the efficiency of grid-connected system.

Description

A kind of single-phase active clamper non-isolated grid-connected inverter

Technical field

The utility model relates to photovoltaic combining inverter fields, and in particular to a kind of non-isolated photovoltaic of single-phase active clamper is simultaneously Net inverter.

Background technique

Solar energy cleanliness without any pollution is very important a kind of new energy.Due to the incident photon-to-electron conversion efficiency of photovoltaic solar plate It is lower, therefore the efficiency for improving photovoltaic combining inverter is particularly important.The common gird-connected inverter with Industrial Frequency Transformer, Since the presence meeting of transformer is so that the efficiency of system reduces, and increases the price of inverter, simultaneously because Industrial Frequency Transformer Volume is larger, it is difficult to install.And the grid-connected system with high frequency transformer, one-stage transfor-mation device is increased, efficiency is also difficult to mention It rises.Therefore to improve system effectiveness, generally use transformerless gird-connected inverter, due to transless so that power grid with it is inverse Become device and there is direct electrical connection, when, there are when distribution capacity, full-bridge inverter can generate larger between solar panels and ground Common mode leakage current, harm is generated to human body, and inverter may be damaged.Therefore to the research of non-isolation type inverter topology by Extensive concern is arrived.The H5 type topology of German SMA company, can efficiently solve current leakage, but due to freewheeling period Electric current flows through body diode, therefore HF switch pipe uses IGBT, IGBT to will cause biggish since there are tail currents Turn-off power loss, the used time due to being pressed by the parasitic capacitance of device, due to device parameters and the difference of pcb board parasitic parameter Can make that leakage current effect is inhibited to be deteriorated with resonant tank that may be present.

Utility model content

The purpose of the utility model is to overcome above-mentioned the deficiencies in the prior art, propose that a kind of single-phase active clamper is non-isolated Photovoltaic combining inverter.

A kind of single-phase active clamper non-isolated grid-connected inverter of the utility model, specifically include first switch tube, Second switch, third switching tube, the 4th switching tube, the 5th switching tube, the 6th switching tube, the 7th switching tube, the 8th switching tube, First diode, the second diode, the first inductance, the second inductance, first capacitor, the second capacitor.

The specific connection type of the utility model circuit are as follows: one end of the positive and first capacitor of DC bus, first open The drain electrode for closing pipe is connected with the drain electrode of third switching tube.One end and the 7th switching tube of the other end of first capacitor and the second capacitor Source electrode connection.The source of the other end of the cathode of DC bus and the second capacitor, the source electrode of second switch and the 4th switching tube Pole connection.The drain electrode of 7th switching tube is connect with the drain electrode of the 8th switching tube.The source electrode of first switch tube and first diode The drain electrode of source electrode, the 5th switching tube of cathode, the 8th switching tube is connected with one end of the first inductance.The other end of first inductance with One end of power grid is connected.The anode of first diode is connect with the drain electrode of the source electrode and second switch of the 6th switching tube.Third The source electrode of switching tube is connect with one end of the cathode of the second diode, the drain electrode of the 6th switching tube and the second inductance.Two or two pole The anode of pipe is connect with the drain electrode of the source electrode and the 4th switching tube of the 5th switching tube.The other end and the power grid other end of second inductance Connection.

Further, the switching tube is all made of the enhanced MOSFET of N-channel.7th switching tube and the 8th switching tube are constituted Two-way switch plays clamping action, does not transmit high-power.First capacitor and the second capacitor's capacity are equal.

Compared with prior art, the utility model circuit has the advantage that are as follows: can in effective solution inversion link by In do not use transformer and caused by common mode current leakage, simultaneously because freewheeling period electric current is not passed through body diode, therefore MOSFET element can be used, and reduce the turn-off power loss as caused by tail currents when as IGBT device shutdown, and SiC bis- Pole pipe can substitute general-purpose diode, the available good inhibition of the loss of Reverse recovery.The utility model circuit can have The inhibition common mode leakage current of effect, while improving the efficiency of grid-connected system.

Detailed description of the invention

Fig. 1 is a kind of single-phase active clamper non-isolated grid-connected inverter topological diagram.

Fig. 2 a~2d is circuit modal graph in network voltage positive-negative half-cycle (wherein with respect to Fig. 1 component lacked and connecting line For off state).

Fig. 3 is 6 switching tube (S in embodiment₁-S₆) drive signal waveform.

Specific embodiment

The specific implementation of the utility model is described further below in conjunction with attached drawing and example, but the guarantor of the utility model It is without being limited thereto to protect range.If being those skilled in the art it is noted that having the process or symbol of not special detailed description below Member can refer to the prior art understand or realize.

As shown in Figure 1, for easy analysis, the device in circuit structure is accordingly to be regarded as the Basic Topological of the utility model Ideal component.

A kind of single-phase active clamper non-isolated grid-connected inverter of the utility model, specifically includes first switch tube S₁, second switch S₂, third switching tube S₃, the 4th switching tube S₄, the 5th switching tube S₅, the 6th switching tube S₆, the 7th switching tube S₇, the 8th switching tube S₈, first diode VD₁, the second diode VD₂, the first inductance L₁, the second inductance L₂, first capacitor C_dc1、 Second capacitor C_dc2。

The specific connection type of the utility model circuit are as follows: anode and the first capacitor C of DC bus_dc1One end, first Switching tube S₁Drain electrode and third switching tube S₃Drain electrode connection.First capacitor C_dc1The other end and the second capacitor C_dc2One end With the 7th switching tube S₇Source electrode connection.The cathode of DC bus and the second capacitor C_dc2The other end, second switch S₂Source Pole and the 4th switching tube S₄Source electrode connection.7th switching tube S₇Drain electrode and the 8th switching tube S₈Drain electrode connection.First switch Pipe S₁Source electrode and first diode VD₁Cathode, the 8th switching tube S₈Source electrode, the 5th switching tube S₅Drain electrode and first electricity Feel L₁One end connection.First inductance L₁The other end be connected with one end of power grid.First diode VD₁Anode opened with the 6th Close pipe S₆Source electrode and second switch S₂Drain electrode connection.Third switching tube S₃Source electrode and the second diode VD₂Cathode, 6th switching tube S₆Drain electrode and the second inductance L₂One end connection.Second diode VD₂Anode and the 5th switching tube S₅'s Source electrode and the 4th switching tube S₄Drain electrode connection.Second inductance L₂The other end connect with the power grid other end.PV Cell table in figure Show photovoltaic cell.

Fig. 2 a~2d is circuit modal graph in network voltage positive-negative half-cycle, in order to enable circuit expression is more clear, wherein The component and connecting line that opposite Fig. 1 lacks are off state.

(1) in the positive half cycle of network voltage, circuit is as shown in Figure 2 a in the modal graph in this stage, first switch tube S₁With Two switching tube S₂It simultaneously turns on, the 6th switching tube S₆Conducting, grid-connected current flow through first switch tube S₁, the first inductance L₁, power grid, Second inductance L₂, the 6th switching tube S₆, second switch S₂It powers to power grid, bridge arm output voltage is U_AB=+U_DC.Bridge arm output A point is U to the voltage of DC bus negative terminal N_AN=U_DC, it is U to the voltage of DC bus negative terminal N that bridge arm, which exports B point,_BN=0, institute With

(2) freewheeling period, circuit is as shown in Figure 2 b in the modal graph in this stage, first switch tube S₁Conducting and second switch Pipe S₂It simultaneously turns off, the 6th switching tube S₆With first diode VD₁Conducting, the 7th switching tube S₇With the 8th switching tube S₈It leads simultaneously It is logical.Electric current flows through the first inductance L₁, power grid, the second inductance L₂, the 6th switching tube S₆, first diode VD₁Afterflow, bridge arm output Voltage is U_AB=0.Due to the 7th switching tube S₇With the 8th switching tube S₈Conducting, bridge arm export A point to the electricity of DC bus negative terminal N Pressure is U_AN=0.5U_DC, it is U to the voltage of DC bus negative terminal N that bridge arm, which exports B point,_BN=0.5U_DC, so

(3) in the negative half period of network voltage, circuit is as shown in Figure 2 c in the modal graph in this stage, third switching tube S3 and Four switching tube S₄It simultaneously turns on, the 5th switching tube S₅Conducting, grid-connected current flow through third switching tube S3, the second inductance L₂, power grid, First inductance L₁, the 5th switching tube S₅, the 4th switching tube S₄It powers to power grid, bridge arm output voltage is U_AB=-U_DC.Bridge arm output A point is U to the voltage of DC bus negative terminal N_AN=0, it is U to the voltage of DC bus negative terminal N that bridge arm, which exports B point,_BN=U_DC, institute With

(4) freewheeling period, circuit is as shown in Figure 2 d in the modal graph in this stage, third switching tube S3 and the 4th switching tube S₄ It simultaneously turns off, the 5th switching tube S₅With the second diode VD₂Conducting, the 7th switching tube S₇With the 8th switching tube S₈It simultaneously turns on.Electricity Stream flows through the second inductance L₂, power grid, the first inductance L₁, the 5th switching tube S₅, the second diode VD₂Afterflow, bridge arm output voltage are U_AB=0.Due to the 7th switching tube S₇With the 8th switching tube S₈Conducting, it is U to the voltage of DC bus negative terminal N that bridge arm, which exports A point,_AN =0.5U_DC, it is U to the voltage of DC bus negative terminal N that bridge arm, which exports B point,_BN=0.5U_DC, so

As the above analysis, common-mode voltage U_cm=0.5U_DCIt keeps constant.Therefore, common mode leakage current can obtain very well Inhibition.Simultaneously because freewheeling period electric current is not passed through body diode, therefore MOSFET element can be used, reduce due to The turn-off power loss as caused by tail currents when IGBT device turns off, and SiC diode can substitute general-purpose diode, it is reversed extensive The available good inhibition of multiple loss.Therefore the utility model circuit can effectively inhibit common mode leakage current, mention simultaneously The efficiency of high grid-connected system.

Claims (4)

1. a kind of single-phase active clamper non-isolated grid-connected inverter, it is characterised in that including first switch tube (S₁), second open Close pipe (S₂), third switching tube (S₃), the 4th switching tube (S₄), the 5th switching tube (S₅), the 6th switching tube (S₆), the 7th switching tube (S₇), the 8th switching tube (S₈), first diode (VD₁), the second diode (VD₂), the first inductance (L₁), the second inductance (L₂), First capacitor (C_dc1), the second capacitor (C_dc2)；Anode and the first capacitor (C of DC bus_dc1) one end, first switch tube (S₁) drain electrode and third switching tube (S₃) drain electrode connection；First capacitor(C_dc1) the other end and the second capacitor (C_dc2) one End and the 7th switching tube (S₇) source electrode connection；The cathode of DC bus and the second capacitor (C_dc2) the other end, second switch (S₂) source electrode and the 4th switching tube (S₄) source electrode connection；7th switching tube (S₇) drain electrode and the 8th switching tube (S₈) leakage Pole connection；First switch tube (S₁) source electrode and first diode (VD₁) cathode, the 8th switching tube (S₈) source electrode, the 5th open Close pipe (S₅) drain electrode and the first inductance (L₁) one end connection；First inductance (L₁) the other end be connected with one end of power grid；The One diode (VD₁) anode and the 6th switching tube (S₆) source electrode and second switch (S₂) drain electrode connection；Third switching tube (S₃) source electrode and the second diode (VD₂) cathode, the 6th switching tube (S₆) drain electrode and the second inductance (L₂) one end connect It connects；Second diode (VD₂) anode and the 5th switching tube (S₅) source electrode and the 4th switching tube (S₄) drain electrode connection；Second Inductance (L₂) the other end connect with the power grid other end.

2. a kind of single-phase active clamper non-isolated grid-connected inverter according to claim 1, it is characterised in that: described Switching tube is all made of the enhanced MOSFET of N-channel.

3. a kind of single-phase active clamper non-isolated grid-connected inverter according to claim 1, it is characterised in that: the 7th Switching tube (S₇) and the 8th switching tube (S₈) two-way switch is constituted, clamping action is played, is not transmitted high-power.

4. a kind of single-phase active clamper non-isolated grid-connected inverter according to claim 1, it is characterised in that: first Capacitor (C_dc1) and the second capacitor (C_dc2) capacitance is equal.