CN207782680U

CN207782680U - A kind of single-phase H6 topologys grid-connected inverter system of low harmony wave

Info

Publication number: CN207782680U
Application number: CN201820266981.8U
Authority: CN
Inventors: 林春旭; 刘关飞; 李晋鹏; 赖伟; 连志华
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2018-02-24
Filing date: 2018-02-24
Publication date: 2018-08-28
Anticipated expiration: 2028-02-24

Abstract

The utility model discloses a kind of single-phase H6 topologys grid-connected inverter systems of low harmony wave, including DC voltage E, inverter, filter and power grid u_g, single-phase full bridge power tube S that wherein inverter is interconnected by six₁~S₆With two sustained diodes₁、D₂Composition, for being alternating voltage by DC voltage E inversions；Filter is LCL filter, including inverter outlet side inductance L₁, grid side inductance L₂With filter capacitor C；Inverter outlet side inductance L₁It is coupled to inverter, grid side inductance L₂It is coupled to power grid, after the alternating voltage that LCL filter transmits inverter is filtered, is transmitted to power grid u_g.The system carries out LCL filtering by introducing efficient single-phase H6 topologys inverter to networking electric current, and the lower grid-connected current of inversion efficiency higher, harmonic content can be obtained, can be widely applied to each large-power occasions；Utilizing status approximation principle design parameter simultaneously, simple and practical, cost is relatively low.

Description

A kind of single-phase H6 topologys grid-connected inverter system of low harmony wave

Technical field

The utility model is related to Technics of Power Electronic Conversion field more particularly to a kind of single-phase H6 topologys gird-connected inverters of low harmony wave System.

Background technology

Under the continuous development of New Energy Industry and intelligent micro-grid, inverter as electricity generation grid-connecting core increasingly by The attention of people.Since gird-connected inverter generally uses the SPWM of upper frequency to modulate, this will cause a large amount of inevitable High-frequency harmonic electric current flows into power grid, to influence grid-connected current quality.In order to reduce grid-connected current harmonic wave, traditional parallel network reverse Device generally use L-type filter is connected with power grid, but L-type filter need inductance value it is larger, result in inductive drop increase, Loss and cost increase, and the response speed of current inner loop is also affected to a certain extent.In recent years, scholar is having studied After LCL filter is to the high-impedance behavior of high fdrequency component, proposes that the LCL type filter of three ranks can replace L-type filter, select Can greatly it be decayed high-frequency harmonic electric current with smaller inductance value, and cost is lower, filter effect is more preferable.However it is existing LCL filter design method is complex, and filter effect is poor, power consumption is big, needs to compensate control.And traditional research and design needle To be all single-phase H4 topologys inverter, compared to the H6 topology inverters that new development in recent years is got up, H4 bridge inverters cannot It realizes that the isolation of power grid and dc-battery plate, system effectiveness and the power grade that bears are relatively low, can not be suitable for high-power grid-connected Occasion.

Invention content

In view of the above problems, the utility model provides a kind of single-phase H6 topologys grid-connected inverter system of low harmony wave, the system It introduces efficient single-phase H6 topologys inverter and LCL filtering is carried out to networking electric current, filtered in low-frequency range and L using LCL filter Wave device has the same filter effect to design filtering parameter, and system design is simple, cost is relatively low, filter effect is preferable.

The utility model specifically adopts the following technical scheme that：

A kind of single-phase H6 topologys grid-connected inverter system of low harmony wave, including DC voltage E, inverter, filter and power grid u_g, wherein the single-phase full bridge power tube S that the inverter is interconnected by six₁~S₆With two sustained diodes₁、 D₂Composition, for being alternating voltage by DC voltage E inversions；The filter is LCL filter, including inverter outlet side electricity Feel L₁, grid side inductance L₂With filter capacitor C.

The power tube S₁~S₆In, S₁~S₄It is IGBT, S₅And S₆It is MOSFET either IGBT or other full-controlled devices, And power tube S₁~S₆It is all made of SPWM controls；The inverter outlet side inductance L₁It is coupled to inverter, grid side inductance L₂Coupling It is connected to power grid, after the alternating voltage that LCL filter transmits inverter is filtered, is transmitted to power grid u_g.The LCL filter In low frequency with L in single inductance L approximate calculation LCL filters₁+L₂Value, obtain the restrictive condition of inductance and capacitance parameter such as Under：

E is DC voltage in formula, and Ug is network voltage virtual value, and P is active power of output, f_kFor switching frequency, f is electricity Net electric voltage frequency.

The beneficial effects of the utility model are：A kind of single-phase H6 topologys grid-connected inverter system of low harmony wave, by high efficiency H6 topology inverters be combined with LCL filter, the lower grid-connected current of inversion efficiency higher, harmonic content can be obtained, can It is widely used in each large-power occasions；Utilizing status approximation principle design parameter simultaneously, system design is simple, and cost is relatively low.

Description of the drawings

Fig. 1 is the topological structure block diagram of the utility model.

Fig. 2 is the LCL filter and L filter Bode diagrams of the utility model.

Fig. 3 is the grid-connected current waveform (amplitude amplifies 10 times) and grid voltage waveform of the utility model.

Fig. 4 is the percent harmonic distortion of the grid-connected current of the utility model.

Specific implementation mode

The utility model is described in further detail below in conjunction with the accompanying drawings.

As shown in Figure 1, a kind of single-phase H6 topologys grid-connected inverter system of low harmony wave, including DC voltage E, inverter, filter Wave device and power grid u_g, wherein the single-phase full bridge power tube S that the inverter is interconnected by six₁~S₆It is continuous with two Flow diode D₁、D₂Composition, for being alternating voltage by DC voltage E inversions；The filter is LCL filter, including inversion Device outlet side inductance L₁, grid side inductance L₂With filter capacitor C.

The power tube S₁~S₆In, S₁~S₄It is IGBT, S₅And S₆It is MOSFET either IGBT or other full-controlled devices, And power tube S₁~S₆It is all made of SPWM controls；The inverter outlet side inductance L₁It is connected to the input of the LCL filter End, the grid side inductance L₂It is connected to the output end of the LCL filter, the input terminal of the LCL filter is coupled to institute Inverter is stated, the output end of the LCL filter is coupled to power grid, the exchange that the LCL filter transmits the inverter After voltage is filtered, it is transmitted to power grid u_g。

As shown in Fig. 2, at low-frequency range (below corner frequency) LCL filter have with L filters as filter effect, Therefore the LCL filter can use L in single inductance L approximate calculation LCL filters in low frequency₁+L₂Value.Under normal circumstances, defeated The size for going out current ripples determines the selection of inductance L minimum values.The 15% of rated current is generally selected as the line on inductance L Wave number is calculated, thus：

In formula, Ug is network voltage virtual value, and P is active power of output, f_kFor switching frequency, d (t) is duty ratio, u_c (t) it is both ends of filter capacitor voltage.Due to the switching frequency f of the grid-connected inverter system_kMuch larger than work frequency f, therefore can ：

u_c(t)=d (t) (3)

Work as u_c(t)=E/2 when, Δ I_LThere is maximum value：

Therefore the restrictive condition of inductance parameters is obtained：

According still further to L₁/L₂Value is about that 5~10 can be obtained filter inductance parameter.

In Practical Project, influence of the capacitance parameter to system power capacity is usually less than 10%, take 5% carry out calculate can Obtain the restrictive condition of inductance parameters：

The filter of the utility model design is relatively simple as can be seen from the above analysis, has apparent calculating advantage. The utility model has carried out simulating, verifying based on single-phase H6 gird-connected inverters to the LCL filter design scheme of proposition, using imitative It is as shown in Figure 3 and Figure 4 that true tool MATLAB/Simulink obtains simulation result.Wherein, single-phase full-bridge inverter uses unipolarity Modulation, using grid-connected current and the quasi- PR control strategies of capacitance current two close cycles, quasi- PR controller transfer functions are：

In formula, K_pFor scale parameter, K_RFor resonant parameter, ω₀For resonance fundamental wave angular frequency₀, ω_cFor frequency bandwidth.

Fig. 3 is grid-connected current waveform (amplitude amplify 10 times) and network voltage simulation waveform, as can be seen from the figure electric Net voltage and grid-connected current illustrate that the system may be implemented stable, High Power Factor and be incorporated into the power networks almost with frequency with phase； Fig. 4 is the percent harmonic distortion of the system wherein five cycles of grid-connected current under simulated environment, its content is only as seen from the figure 1.06%, effectively inhibit current harmonics caused by HF switch.

Claims

1. a kind of single-phase H6 topologys grid-connected inverter system of low harmony wave, including DC voltage E, inverter, filter and power grid u_g, It is characterized in that：The single-phase full bridge power tube S that the inverter is interconnected by six₁~S₆With two two poles of afterflow Pipe D₁、D₂Composition, for being alternating voltage by DC voltage E inversions；The filter is LCL filter, including inverter output Side inductance L₁, grid side inductance L₂With filter capacitor C.

2. the single-phase H6 topologys grid-connected inverter system of a kind of low harmony wave according to claim 1, it is characterised in that：The work( Rate pipe S₁~S₆In, S₁~S₄It is IGBT, S₅And S₆It is MOSFET either IGBT or other full-controlled devices.

3. the single-phase H6 topologys grid-connected inverter system of a kind of low harmony wave according to claim 1, it is characterised in that：The work( Rate pipe S₁~S₆It is all made of SPWM controls.

4. the single-phase H6 topologys grid-connected inverter system of a kind of low harmony wave according to claim 1, it is characterised in that：Described Inverter outlet side inductance L₁It is connected to the input terminal of the LCL filter, the grid side inductance L₂It is connected to the LCL filters The input terminal of the output end of wave device, the LCL filter is coupled to the inverter, the output end coupling of the LCL filter To power grid, after alternating voltage that the LCL filter transmits the inverter is filtered, it is transmitted to power grid u_g。