CN205846856U - A kind of energy storage off-network inverter improves the system of uninterrupted power supply power factor - Google Patents

Abstract

This utility model relates to supply network field, particularly relates to the continual electric power system of supply network.System includes: the first power supply branch road, including mains-supplied unit, mains-supplied unit controllably powers to the load；Second power supply branch road, with the first power supply branch circuit parallel connection in the two ends of load, the second power supply branch road connects inverter unit, and inverter unit powers to the load, and inverter unit, when the first duty, individually exports constant voltage and frequency to load；Inverter unit, when the second duty, by the phase place angle between output voltage and the output voltage of the output voltage of inverter unit and mains-supplied unit of control inverter unit, adjusts the power factor of the first power supply branch road.When civil power is normal, inverter improves the power factor of electrical network by controlling the phase place angle between its output voltage and itself and civil power, when city's electrical anomaly, energy storage off-network inverter is individually for load supplying, improves load supplying reliability.

Description

A kind of energy storage off-network inverter improves the system of uninterrupted power supply power factor

Technical field

This utility model relates to supply network field, particularly relates to the continual electric power system of supply network.

Background technology

At present, bulk power grid combines with distributed power generation and is known as being to save by a lot of electricity power experts in the world Investment, reduction energy consumption, raising electric network security and the main method of motility, be the developing direction of 21 century power industry.Point In cloth generating, regenerative resource wind energy and solar energy are as clean energy resource, inexhaustible, but due to by weather The impact of condition change, its output has stochastic volatility, intermittence, unstability, extensive also in particular with it Enter electrical network, bring challenge greatly to power system production and operation.

In a distributed manner based on generation technology, concentrated-distributed power supply, energy-storage units and controllable burden, in the microgrid of one, are The important component part that following intelligent grid is built.Energy-storage units is as link requisite in microgrid, it is ensured that distribution Harmony that formula is powered and seriality and reduce the accident impact on system, improve new energy power generation grid-connection performance, Improve power quality, balance generated output square with workload demand, raising efficiency, reduction system dynamics change etc. Face plays an important role.

Disclosing a kind of energy router for distributed power generation in prior art, the method can be according to stabilized power source With the different power supply modes that the working condition of new forms of energy brute supply adjusts load power source in real time, but due to control static switch Be switched on or off can inevitably cause load momentary power failure, cause the service behaviour affecting supply network, the most surely Qualitative.

Utility model content

The purpose of this utility model is, it is provided that a kind of energy storage off-network inverter improve uninterrupted power supply power factor be System, the technical problem unstable to solve the power supply unit powering load of prior art, and improve under mains-supplied pattern The power factor of load.

A kind of energy storage off-network inverter improves the system of uninterrupted power supply power factor, including:

One first power supply branch road, including a mains-supplied unit, described mains-supplied unit passes through one first switch element Controllably to a load supplying；

One second power supply branch road, with described first power supply branch circuit parallel connection in the two ends of described load, described second power supply Connect an inverter unit on road, described inverter unit for a DC input voitage is converted to ac output voltage with to Described load supplying, and

Described inverter unit, when the first duty, individually exports constant voltage and frequency to described load；

Described inverter unit is when the second duty, by controlling output voltage and the institute of described inverter unit State the phase place angle between the output voltage of inverter unit and the output voltage of mains-supplied unit, adjust described first and supply The power-factor cos δ, δ of electricity branch road represents the output voltage V of inverter unit_cElectric current I with mains-supplied unit_gBetween folder Angle.

Preferably, described inverter unit is controlled by a second switch unit being series in described second power supply branch road System ground is to described load supplying.

Preferably, described first switch element is relay switch.

Preferably, described inverter unit is single-phase energy storage off-network inverter or three-phase energy storage inverter.

A kind of energy storage off-network inverter improves the method for uninterrupted power supply power factor, based on improving energy storage off-network inverter The system of uninterrupted power supply, described method includes:

Step 1, it is judged that described mains-supplied unit the most normally works；If it is, perform step 2, if it does not, perform step Rapid 3；

Step 2, closes second switch unit, described mains-supplied unit and described inverter unit simultaneously to described load Power supply, and by the output voltage of the described inverter unit of control and the output voltage of described inverter unit and described civil power Phase place angle between the output voltage of power supply unit, thus adjust the power-factor cos δ, wherein δ of described first power supply branch road Represent the output voltage V of inverter unit_cOutput electric current I with mains-supplied unit_gBetween angle；

Step 3, disconnects the first switch element, and described inverter unit individually exports constant voltage and frequency to described load Rate.

Preferably, by the output voltage of described mains-supplied unit is carried out phase-locked by the way of, control described inversion Between the output voltage of the output voltage of device unit and the output voltage of described inverter unit and described mains-supplied unit Phase place angle.

Preferably, described phase-locked method includes:

$V_c=\frac{1}{{\mathrm{\ωL}}_1}\sqrt{{\left({\mathrm{\ωL}}_1{i}_{load\_1}\right)}^2-2{\mathrm{\ωV}}_g{i}_{load\_1}{L}_{1}sin\mathrm{\δ}+V_g^2}---\left(1\right)$

$\mathrm{\α}=arcsin\frac{{\mathrm{\ωL}}_1{I}_{g}cos\mathrm{\δ}}{V_c}---\left(2\right)$

Wherein, V_cRepresenting the output voltage of inverter unit, L1 is the inductance value of inductance in described first power supply branch road, i_{load_1}Represent load current i_loadPositive sequence fundamental current, V_gRepresenting the output voltage of mains-supplied unit, α represents V_gWith V_cIt Between angle；

The V that described inverter unit is obtained according to formula (1), (2)_cAnd the output electricity that α is to described mains-supplied unit It is pressed into line trace, and on the basis of phase-locked, realize V_cAnd V_gPhase α.

Preferably, described step 3 also includes:

When described mains-supplied cell operation exception, disconnect the first switch element, after its normally work, described inversion Device unit continues to carry out phase-locked to described mains-supplied unit.

This utility model describes a kind of method and system improving energy storage off-network inverter uninterrupted power supply, when civil power just When often working, energy storage off-network inverter improves electrical network by controlling the phase place angle between its output voltage and itself and civil power Power factor；When city's electrical anomaly, energy storage off-network inverter it is individually for load supplying, and exports constant voltage and frequency Rate, it is achieved the uninterrupted power supply to load, improves load supplying reliability.

Accompanying drawing explanation

Fig. 1 is the frame that a kind of energy storage off-network inverter of the present utility model improves the system of uninterrupted power supply power factor Figure；

Fig. 2 is energy storage off-network inverter and the voltage-phase of civil power and the vectogram of mains current phase place.

In Fig. 1, L1 is inductance, i_oRepresent off-network energy storage inverter output electric current, i_loadRepresent load current.

V in Fig. 2_gRepresent the output voltage of civil power, V_cRepresenting the output voltage of inverter, Δ V represents civil power and inverter The vector difference of output voltage, α represents the angle between civil power and the output voltage of inverter, I_gRepresent that civil power flows into load Electric current, θ represents I_gAnd V_cBetween angle, β represents Δ V and V_cBetween angle, δ represents V_cWith I_gBetween angle.

Detailed description of the invention

A kind of energy storage off-network inverter of the present utility model improves the system of uninterrupted power supply power factor, including:

One first power supply branch road, including a mains-supplied unit, mains-supplied unit is controlled by one first switch element System ground is to a load supplying；

One second power supply branch road, with the first power supply branch circuit parallel connection in the two ends of load, the second power supply branch road connects one inverse Become device unit, inverter unit for a DC input voitage being converted to ac output voltage to power to the load, and

Inverter unit, when the first duty, individually exports constant voltage and frequency to load；

Inverter unit is when the second duty, by controlling output voltage and the inverter unit of inverter unit Output voltage and the output voltage of mains-supplied unit between phase place angle, adjust the power factor of the first power supply branch road Cos δ, δ represent the output voltage V of inverter unit_cElectric current I with mains-supplied unit_gBetween angle.

As it is shown in figure 1, specifically, the first power supply branch road is mains circuit, including a mains-supplied unit and the first switch K1, the voltage swing at mains-supplied unit two ends is V_g；Second power supply branch road is the operating circuit of inverter unit, this inverter The output voltage of unit outfan is V_c。

When mains circuit and inverter unit the most normally work, Guan Bi the first switch K1 and second switch K2, now, inverse Becoming device unit and be in the second duty, inverter is by controlling V_cAnd V_gBetween phase place angle α improve the merit of whole electrical network Rate factor cos δ, improves the utilization ratio of electric energy.When mains circuit occurs abnormal, inverter unit is in another work shape State, is individually for load supplying by inverter unit, exports constant voltage and frequency for it, it is achieved that the uninterrupted confession to load Electricity, improves load supplying reliability.And the first switch K1 connected can automatically cut off when mains circuit appearance is abnormal Mains circuit, it is ensured that the safety of circuit.

Preferred embodiment, the first power supply branch road also includes one first inductance to this utility model, and the first inductance is series at On first power supply branch road.

Specifically, connect an inductance L1 in mains circuit, it is possible to ensures that inverter can adjust civil power output voltage and city Phase place angle between electricity output electric current.

This utility model preferred embodiment, inverter unit by one be series in the second power supply branch road second open Close unit controllably to power to the load.

Specifically, connect a second switch K2 with inverter unit, when preventing inverter unit from occurring abnormal, automatically cuts off The work branch of inverter, it is ensured that the safety of circuit.

Preferred embodiment, the first switch element is relay switch to this utility model.

Relay switch plays overcurrent protection, the effect of overvoltage protection, belongs to a kind of switch automatically, when the electric current in civil power Or voltage excessive time, relay switch can automatic trip, disconnect place circuit, prevent circuit from damaging further.

Preferred embodiment, inverter unit is single-phase energy storage off-network inverter or three-phase energy storage inversion to this utility model Device.

A kind of method improving energy storage off-network inverter uninterrupted power supply, based on one improve energy storage off-network inverter not between The system of cut-off electricity, including:

Step 1, it is judged that mains-supplied unit the most normally works；If it is, perform step 2, if it does not, perform step 3；

Step 2, closes second switch unit, and mains-supplied unit and inverter unit power to the load simultaneously, and pass through Control between output voltage and the output voltage of the output voltage of inverter unit and mains-supplied unit of inverter unit Phase place angle, thus adjust the power-factor cos δ of the first power supply branch road, wherein δ represents the output voltage V of inverter unit_c Output electric current I with mains-supplied unit_gBetween angle；

Step 3, disconnects the first switch element, and inverter unit individually exports constant voltage and frequency to load.

Specifically, when mains circuit normally works, the first switch K1 and second switch K2 closes, and loads by civil power electricity Road powers；And by controlling V_cAnd V_cWith V_gBetween angle α, control δ, at this moment load by mains circuit and inverter list Unit powers simultaneously, simultaneously works as improving the effect of power factor of electric network.When mains circuit occurs abnormal, the first switch K1 breaks Opening, inverter unit individually exports constant voltage and frequency to load, so that load obtains lasting voltage, steady load Work.This utility model preferred embodiment, by the output voltage of mains-supplied unit is carried out phase-locked on the basis of, come Control between output voltage and the output voltage of the output voltage of inverter unit and mains-supplied unit of inverter unit Phase place angle.

Specifically, phase-locked is exactly the phase and frequency of a certain another signal of signal trace so that with another signal Phase place keeps synchronizing.As in figure 2 it is shown, when the phase place angle α of the output voltage of inverter unit and two voltages keep constant after, Voltage vector difference DELTA V of mains-supplied unit and inverter also immobilizes, and this makes it possible to obtain a fixing civil power and supplies Phase place angle δ between output voltage and the output electric current of mains-supplied unit of electric unit, thus obtain stable cos δ-value, Namely obtain the power factor of stable civil power.And power factor is to weigh a coefficient of electrical equipment efficiency height, generation The table load capacity size of electrical network, power factor is low, illustrates that circuit is big for the reactive power of alternating magnetic field conversion, thus drops The low utilization rate of equipment, adds line powering loss.

Preferred embodiment, described phase-locked mode includes this utility model:

$V_c=\frac{1}{{\mathrm{\ωL}}_1}\sqrt{{\left({\mathrm{\ωL}}_1{i}_{load\_1}\right)}^2-2{\mathrm{\ωV}}_g{i}_{load\_1}{L}_{1}sin\mathrm{\δ}+V_g^2}---\left(1\right)$

$\mathrm{\α}=arcsin\frac{{\mathrm{\ωL}}_1{I}_{g}cos\mathrm{\δ}}{V_c}---\left(2\right)$

Wherein, V_cRepresenting the output voltage of inverter unit, L1 is the inductance value of inductance, i in the first power supply branch road_{load_1} Represent load current i_loadPositive sequence fundamental current, V_gRepresenting the output voltage of mains-supplied unit, α represents V_gWith V_cBetween Angle；

The V that inverter unit is obtained according to formula (1), (2)_cAnd α the output voltage of mains-supplied unit is carried out with Track, and on the basis of phase-locked, realize V_cAnd V_gPhase α.

The concrete derivation in formula (1), (2) is as follows:

Mains-supplied unit is powered to the load with inverter parallel jointly by the inductance L1 connected with mains-supplied unit, Wherein the output of mains-supplied unit is:

P_g=V_cI_gCos θ=V_cI_gsinβ (3)

And the electric current that mains-supplied unit flows to load by inductance L1 is:

I_g=Δ V/ (ω L₁) (4)

Then mains-supplied unit output is rewritten as:

P_g=V_cΔVsinβ/(ωL₁) (5)

See the vectogram in Fig. 2, have according to sine:

$\frac{V_g}{sin\mathrm{\β}}=\frac{\mathrm{\Δ}V}{\sin \mathrm{\α}}---\left(6\right)$

Formula (6) is brought into formula (5) obtain mains-supplied unit output flow to load power:

$P_g=\frac{V_c{V}_{g}sin\mathrm{\α}}{{\mathrm{\ωL}}_1}---\left(7\right)$

By formula (7) it is recognised that work as the phase place of the output voltage of the advanced inverter of voltage-phase of mains-supplied unit, Mains-supplied unit provides energy to load,In interval, mains-supplied unit increases along with α to the energy of load offer Add and increase；In identical α angle, inductance L1 is the least, and the energy that mains-supplied unit provides to load is the biggest.

If the sinusoidal wave form that the output voltage of mains-supplied unit is a standard, then the voltage at inductance L1 two ends is V_L1 (t)=V_gsin(ωt)-V_cSin (ω t-α), flows through the electric current I of L1_g(t) be:

I_g(t)=I_gSin (ω t-δ) (8) can be derived from by above formula:

$I_g=\frac{1}{{\mathrm{\ωL}}_1}\sqrt{{\left(V_{c}sin\mathrm{\α}\right)}^2+{(V_g-V_{c}cos\mathrm{\α})}^2}---\left(9\right)$

$\mathrm{\δ}=arcsin\left(\frac{V_g-V_{c}cos\mathrm{\α}}{\sqrt{{\left(V_{c}sin\mathrm{\α}\right)}^2+{(V_g-V_{c}cos\mathrm{\α})}^2}}\right)---\left(10\right)$

From (9), (10) two formulas it can be seen that owing to the output voltage of mains-supplied unit is unmodifiable, for terrible Desired electric current on L1, can only be by regulating the output voltage amplitude V of inverter_cRealize with phase place angle α.

To load current i_loadCarrying out discrete Fourier transform (DFT), can obtain its positive sequence fundamental current comprised is i_{load_1}。 When mains-supplied unit and inverter the most normally work, in order to ensure that civil power power factor is preferable, now civil power passes through inductance L1 gives the supply current I of load_g=i_{load_1}Time, the power factor of electrical network is cos δ.

To this end, work as the i obtaining giving_{load_1}During with δ, from formula (9), (10) available above-mentioned formula (1), (2).

From formula (1), (2) are it can be seen that for the ideal current on we inductance L1 to be followed the tracks of, can calculate and want The voltage followed the tracks of.Wherein δ is setting value, and the δ of setting is the least, and raising power factor of electric network cos δ effect is the biggest, exports simultaneously Power is the biggest.

Above-mentioned embodiment is by adjusting the output voltage V of inverter_cWith this output voltage V_cDefeated with mains-supplied unit Go out voltage V_cBetween phase place angle α, thus control the power factor of inverter system, it is achieved the uninterrupted power supply of load, carry High load supplying reliability.

Preferred embodiment, step 3 also includes this utility model: when mains-supplied cell operation exception, disconnects the One switch element, after its normally work, inverter unit continues to carry out phase-locked to mains-supplied unit.

Specifically, when mains-supplied unit occur abnormal can not normally time, in order to guarantee to carry out to load constantly Power supply, when after mains-supplied unit power-off, the first switch K1 disconnects, inverter unit continue the voltage fixing to load conveying and Electric current.Until mains-supplied unit recovers normal work, inverter unit continues to start to perform from step 1, and to mains-supplied The output voltage of unit carries out phase-locked, makes mains-supplied unit and inverter unit be powered load simultaneously.

The foregoing is only this utility model preferred embodiment, not thereby limit embodiment of the present utility model and Protection domain, to those skilled in the art, it should in can appreciate that all utilization this utility model description and diagram Hold the scheme obtained by the equivalent made and obvious change, all should be included in protection model of the present utility model In enclosing.

Claims (5)

1. the system of an energy storage off-network inverter raising uninterrupted power supply power factor, it is characterised in that including:

One first power supply branch road, including a mains-supplied unit, described mains-supplied unit is controlled by one first switch element System ground is to a load supplying；

One second power supply branch road, with described first power supply branch circuit parallel connection in the two ends of described load, on described second power supply branch road Connecting an inverter unit, described inverter unit is for being converted to ac output voltage with to described by a DC input voitage Load supplying, and

Described inverter unit, when the first duty, individually exports constant voltage and frequency to described load；

Described inverter unit is when the second duty, by controlling the output voltage of described inverter unit and described inverse Become the phase place angle between output voltage and the output voltage of mains-supplied unit of device unit, adjust described first power supply The power-factor cos δ, δ on road represents the output voltage V of inverter unit_cElectric current I with mains-supplied unit_gBetween angle.

Energy storage off-network inverter the most according to claim 1 improves the system of uninterrupted power supply power factor, and its feature exists In, described first power supply branch road also includes that one first inductance, described first inductance are series on described first power supply branch road.

Energy storage off-network inverter the most according to claim 1 improves the system of uninterrupted power supply power factor, and its feature exists In, described inverter unit is series at the second switch unit in described second power supply branch road controllably to described negative by one Carry power supply.

Energy storage off-network inverter the most according to claim 1 improves the system of uninterrupted power supply power factor, and its feature exists In, described first switch element is relay switch.

Energy storage off-network inverter the most according to claim 1 improves the system of uninterrupted power supply power factor, and its feature exists In, described inverter unit is single-phase energy storage off-network inverter or three-phase energy storage inverter.