CN106026193A - Micro power grid multi-inverter parallel control system and work method thereof - Google Patents

Abstract

The invention discloses a micro power grid multi-inverter parallel control system and a work method thereof. Operation in island and grid connected modes can be realized, transition between the two operation modes can be realized without the need of a corresponding control method for switching, system reliability is high, and dynamic performance is enhanced. Differential control on active power is added during power control, an active power dynamic response speed of a system is accelerated, moreover, in the grid connected operation mode, integration control on power grid reactive power during power control exists, so control on power factors of various distributed generation units and common connection points of a power grid is realized, rated capacities of the distributed generation units can be different and have not special requirements, and properties of relatively strong adaptability and relatively good application prospect are realized.

Description

A kind of micro-capacitance sensor multi-inverter parallel control system and method for work thereof

Technical field

The present invention relates to a kind of micro-capacitance sensor multi-inverter parallel control system and method for work thereof, belong to distributed power generation and Intelligent power grid technology field.

Background technology

Access the technical barrier of electrical network to solve distributed power source, the power system scholars that are correlated with propose micro-capacitance sensor Concept.Micro-capacitance sensor is consisted of the network interconnection decline source, energy conversion device and local load of distribution, it is possible to real Existing self-contr ol, the Partial discharge system protected and manage.In micro-capacitance sensor, great majority distribution declines source all by inverse Become device interface incoming transport bus, thus define a kind of multi-inverter parallel running environment.

There are isolated island and grid-connected two kinds of operational modes in micro-capacitance sensor.Under islet operation pattern, inverter is by adjusting voltage Amplitude and frequency and then obtain the power-sharing between each distributed generation unit and control；It is incorporated into the power networks under pattern, is protecting On the basis of holding islet operation pattern all control function, mainly realize merit at each distributed generation unit points of common connection The accurate regulation that rate flows to.When micro-capacitance sensor according to circumstances needs islet operation or external electrical network to break down, should be rapid Disconnect the connection with electrical network, proceed to islet operation pattern；When external electrical network service restoration is normal, or according to circumstances need When wanting micro-grid connection to run, the micro-capacitance sensor being in islet operation pattern is linked public electric wire net again.At present, two Planting in mode transition procedure, need switching to run control strategy accordingly, the stationarity of handoff procedure needs to grind further Study carefully raising.

Summary of the invention

For the deficiencies in the prior art, the present invention provides a kind of micro-capacitance sensor multi-inverter parallel control system and work side thereof Method.

Technical scheme is as follows:

A kind of micro-capacitance sensor multi-inverter parallel control system and method for work thereof, it is how inverse that this method of work is applicable to micro-capacitance sensor Becoming device parallel control system, described micro-capacitance sensor multi-inverter parallel control system includes the distributed power generation list of N number of parallel connection Unit, ac bus, load, low bandwidth communication, grid-connected switch, transformator, electrical network；Described distributed generation unit Being sequentially connected with formed by micro-source, H-bridge inverter circuit, LC wave filter, switch, each distributed generation unit also includes Its respective controller；The distributed generation unit of described N number of parallel connection is by its respective switch and described ac bus Connecting, described load is connected on described ac bus；Described grid-connected switch is connected with described ac bus, simultaneously with Transformator, electrical network are sequentially connected；Described low bandwidth communication is by the controller 1 and remaining N-1 in distributed generation unit 1 Controller in individual distributed generation unit connects together.

In described distributed generation unit 1, the Gather and input amount of described controller 1 has: line voltage v_g, grid-connected Electric current i_g, ac bus voltage v_L, distributed generation unit 1 output voltage v_o1, distributed generation unit 1 exports Electric current i_o1, distributed generation unit 1 H-bridge inverter circuit output electric current i₁, the output of described controller 1 has: The H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁, grid-connected reactive power Q_g.For except distributed For N-1 distributed generation unit controller of remaining beyond electric unit 1, its Gather and input amount and output and institute State controller 1 different, but this N-1 distributed generation unit controller Gather and input amount is the most identical with output, with As a example by distributed generation unit i, 2≤i≤N, its controller i Gather and input amount has: ac bus voltage v_L, distribution Formula generator unit i output voltage v_oi, distributed generation unit i export electric current i_oi, the H of distributed generation unit i Bridge inverter circuit output electric current i_i, grid-connected reactive power Q_g, output has: the H bridge inversion of distributed generation unit i Circuit duty cycle signals S_i.Grid-connected reactive power Q_gExported by described controller 1 and transmit to it through described low bandwidth communication In remaining N-1 distributed generation unit controller.

The specific works method of micro-capacitance sensor multi-inverter parallel control system of the present invention includes:

(1) running initially in micro-capacitance sensor multi-inverter parallel control system, first distributed generation unit 1 breaker in middle closes Close, distributed generation unit 1 is connected to ac bus；In each sampling period starting point of controller 1, gather Line voltage v_g, grid-connected current i_g, ac bus voltage v_L, distributed generation unit 1 output voltage v_o1, distribution Formula generator unit 1 exports electric current i_o1, distributed generation unit 1 H-bridge inverter circuit output electric current i₁, and through fortune Calculate and process, obtain the H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁, grid-connected reactive power Q_g； S₁Driving H-bridge inverter circuit works, and distributed generation unit 1 is able to independent operating；

(2) distributed generation unit i switch Guan Bi, is connected to ac bus by distributed generation unit i；Controller I gathers ac bus voltage v_L, distributed generation unit i output voltage v_oi, distributed generation unit i export electric current i_oi, distributed generation unit i H-bridge inverter circuit output electric current i_i, input grid-connected reactive power Q_g, through computing with Process, obtain the H-bridge inverter circuit duty cycle signals S of distributed generation unit i_i；S_iDrive H-bridge inverter circuit work Make, distributed generation unit i and distributed generation unit 1 islet operation in parallel；

(3) distributed generation unit controllers all in system are sent grid-connected synch command so that the electricity of each of which Pressure reference value is the most identical, and the rated capacity of the most each distributed generation unit is the most identical, its respective output voltage All tend to identical；

(4) grid-connected switch Guan Bi, all distributed generation unit send electric energy in addition to for load supplying, dump energy Being incorporated to AC network, this is the pattern of being incorporated into the power networks.

According to currently preferred, in described step (1), controller 1 computing obtains the H of distributed generation unit 1 Bridge inverter circuit duty cycle signals S₁Concrete steps include:

A, controller 1 are according to line voltage v_g, grid-connected current i_gIt is calculated grid-connected reactive power Q_g, according to exchange Busbar voltage v_L, distributed generation unit 1 export electric current i_o1It is calculated distributed generation unit 1 and exports wattful power Rate P₁With output reactive power Q₁；

B, by grid-connected reactive power Q_g, distributed generation unit 1 active power of output P₁With output reactive power Q₁Meter Calculation obtains angular frequency variable quantityWith voltage magnitude variable quantity

$\left\{\begin{array}{c}{\widehat{\mathrm{\ω}}}_1=m_1\left({\stackrel{\‾}{P}}_1-P_1\right)+k_{d1}\frac{d}{dt}({\stackrel{\‾}{P}}_1-P_1)\\ {\hat{V}}_1=-n_1{Q}_1-k_{i1}\∫Q_{g}dt\end{array}\right.---\left(I\right)$

In formula I,For the rated generation amount of distributed generation unit 1, k_d1、k_i1It is respectively controller 1 power The differential coefficient controlled and integral coefficient, m₁And n₁For the sagging gain of controller 1, t is time variable；

C, to line voltage v_gSurvey calculation obtains controller 1 line voltage angular frequencyGrid voltage amplitude Electric network voltage phase angle θ_g；

D, by controller 1 line voltage angular frequencyGrid voltage amplitudeElectric network voltage phase angle θ_g, angular frequency Rate variable quantityVoltage magnitude variable quantitySynthesized reference voltage composite valueComputing formula is:

$v_{ref1}^{*}=({\stackrel{\‾}{V}}_1+{\hat{V}}_1)sin\[({\stackrel{\‾}{\mathrm{\ω}}}_1+{\widehat{\mathrm{\ω}}}_1)t+{\mathrm{\θ}}_g\]---\left(II\right);$

E, reference voltage composite valueDeduct distributed generation unit 1 and export electric current i_o1With the product of virtual impedance, Obtain voltage reference value v_ref1；

F, distributed generation unit 1 output voltage v_o1, voltage reference value v_ref1, distributed generation unit 1 export electricity Stream i_o1Regulate through Control of Voltage, obtain reference current

G, reference currentDistributed generation unit 1 output voltage v_o1, distributed generation unit 1 H bridge inversion electricity Road output electric current i₁Control to adjust through electric current, obtain modulation wave signal D₁；Modulation wave signal D₁PWM is carried out with triangular carrier Modulation, obtains the H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁。

According to currently preferred, in described step (2), controller i computing obtains the H of distributed generation unit i Bridge inverter circuit duty cycle signals S_iConcrete steps include:

H, controller i are according to ac bus voltage v_L, distributed generation unit i export electric current i_oiIt is calculated distribution Formula generator unit i active power of output P_iWith output reactive power Q_i；

I, by distributed generation unit i active power of output P_iWith output reactive power Q_i, grid-connected reactive power Q_gMeter Calculation obtains controller i angular frequency variable quantityWith voltage magnitude variable quantity

$\left\{\begin{array}{c}{\widehat{\mathrm{\ω}}}_i=m_i\left({\stackrel{\‾}{P}}_i-P_i\right)+k_{di}\frac{d}{dt}({\stackrel{\‾}{P}}_i-P_i)\\ {\hat{V}}_i=-n_i{Q}_i-k_{ii}\∫Q_{g}dt\end{array}\right.---\left(III\right)$

In formula III,For the rated generation amount of distributed generation unit i, k_di、k_iiIt is respectively controller i power The differential coefficient controlled and integral coefficient, m_iAnd n_iFor the sagging gain of controller i, t is time variable；

J, to ac bus voltage v_LSurvey calculation obtains controller i load voltage angular frequencyLoad voltage amplitudeLoad voltage phase angle θ_L；

K, by controller i angular frequency variable quantityVoltage magnitude variable quantityLoad voltage angular frequencyLoad Voltage magnitudeLoad voltage phase angle θ_LSynthetic controller i reference voltage composite valueComputing formula is:

$v_{refi}^{*}=({\stackrel{\‾}{V}}_L+{\hat{V}}_i)sin\[({\stackrel{\‾}{\mathrm{\ω}}}_L+{\widehat{\mathrm{\ω}}}_i)t+{\mathrm{\θ}}_L\]---\left(IV\right);$

L, controller i reference voltage composite valueDeduct distributed generation unit i and export electric current i_oiWith virtual impedance Product, obtain controller i voltage reference value v_refi；

M, distributed generation unit i output voltage v_oi, controller i voltage reference value v_refi, distributed generation unit i Output electric current i_oiRegulate through Control of Voltage, obtain reference current

N, reference currentDistributed generation unit i output voltage v_oi, the H bridge inversion of distributed generation unit i Circuit output current i_iControl to adjust through electric current, obtain modulation wave signal D_i；Modulation wave signal D_iCarry out with triangular carrier PWM, obtains the H-bridge inverter circuit duty cycle signals S of distributed generation unit i_i。

According to currently preferred, in described step (3), distributed generation unit controllers all in system are sent Grid-connected synch command so that the voltage reference value of each of which is the most identical, final all distributed generation unit output electricity Pressure all tends to identical, and specific implementation method is:

O, grid-connected synch command send, and distributed generation unit 1 middle controller 1 slowly regulates angular frequency in formula I Variable quantityWith voltage magnitude variable quantityThe two is gone to zero, then reference voltage composite value in formula II Taper to and line voltage v_gIdentical；

P, distributed generation unit 1 reference voltage composite valueChange makes its output voltage change, ac bus electricity Pressure v_LChange therewith；Meanwhile, distributed generation unit i middle controller i slowly regulates formula III middle controller i angle Frequency variationWith voltage magnitude variable quantityThe two is gone to zero, then formula IV middle controller i is with reference to electricity It is pressed into valueAlong with ac bus voltage v_LChange and change；Finally, all distributed power generations in system Unit output voltage is the most identical.

The invention have the benefit that

1, under micro-capacitance sensor multi-inverter parallel control system can be simultaneously run in isolated island and grid-connected both of which, two kinds of operations Transition between pattern need not the switching of corresponding control method, and system reliability is high, dynamic property strengthens；

2, during power controls, the differential to active power controls, and accelerates the active power dynamic responding speed of system；

3, being incorporated into the power networks under pattern, there is the integration control to power system reactive power in controlling in power so that each distributed The power factor of the points of common connection of generator unit and electrical network is strictly controlled；

4, under conditions of distributed generation unit rated capacity is inconsistent, the present invention still can obtain preferable operational effect.

Accompanying drawing explanation

Fig. 1 is micro-capacitance sensor multi-inverter parallel Control system architecture schematic diagram of the present invention；

In Fig. 1, N >=2 and 2≤i≤N, lower same；

Fig. 2 is the schematic flow sheet of controller 1 method of work of distributed generation unit 1 of the present invention；

Fig. 3 is the schematic flow sheet of the controller i method of work of distributed generation unit i of the present invention；

Fig. 4 is the phantom output electric current design sketch using the present invention；

Output Current amplifier effect when Fig. 5 is for using two distributed generation unit parallel connection islet operation under simulated conditions of the present invention Fruit figure；

Fig. 6 exports Current amplifier effect for using two distributed generation unit parallel connections under simulated conditions of the present invention when being incorporated into the power networks Fruit figure.

Detailed description of the invention

Below in conjunction with Figure of description, the invention will be further described.

Micro-capacitance sensor multi-inverter parallel control system of the present invention is as shown in Figure 1.Described micro-capacitance sensor multi-inverter parallel controls System includes the distributed generation unit of N number of parallel connection, ac bus, load, low bandwidth communication, grid-connected switch, change Depressor, electrical network；Described distributed generation unit is sequentially connected with by micro-source, H-bridge inverter circuit, LC wave filter, switch Composition, each distributed generation unit also includes its respective controller；The distributed generation unit of described N number of parallel connection Being connected with described ac bus by its respective switch, described load is connected on described ac bus；Described grid-connected Switch is connected with described ac bus, is sequentially connected with transformator, electrical network simultaneously；Described low bandwidth communication is by distributed Controller in N-1 distributed generation unit of controller 1 in generator unit 1 and remaining connects together.

In described distributed generation unit 1, the Gather and input amount of described controller 1 has: line voltage v_g, grid-connected Electric current i_g, ac bus voltage v_L, distributed generation unit 1 output voltage v_o1, distributed generation unit 1 exports Electric current i_o1, distributed generation unit 1 H-bridge inverter circuit output electric current i₁, the output of described controller 1 has: The H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁, grid-connected reactive power Q_g.For except distributed For N-1 distributed generation unit controller of remaining beyond electric unit 1, its Gather and input amount and output and institute State controller 1 different, but this N-1 distributed generation unit controller Gather and input amount is the most identical with output, with As a example by distributed generation unit i, 2≤i≤N, its controller i Gather and input amount has: ac bus voltage v_L, distribution Formula generator unit i output voltage v_oi, distributed generation unit i export electric current i_oi, the H of distributed generation unit i Bridge inverter circuit output electric current i_i, grid-connected reactive power Q_g, output has: the H bridge inversion of distributed generation unit i Circuit duty cycle signals S_i.Grid-connected reactive power Q_gExported by described controller 1 and transmit to it through described low bandwidth communication In remaining N-1 distributed generation unit controller.

The specific works method of micro-capacitance sensor multi-inverter parallel control system of the present invention includes:

(1) running initially in micro-capacitance sensor multi-inverter parallel control system, first distributed generation unit 1 breaker in middle closes Close, distributed generation unit 1 is connected to ac bus；In each sampling period starting point of controller 1, gather Line voltage v_g, grid-connected current i_g, ac bus voltage v_L, distributed generation unit 1 output voltage v_o1, distribution Formula generator unit 1 exports electric current i_o1, distributed generation unit 1 H-bridge inverter circuit output electric current i₁, and through fortune Calculate and process, obtain the H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁, grid-connected reactive power Q_g； S₁Driving H-bridge inverter circuit works, and distributed generation unit 1 is able to independent operating；

(2) distributed generation unit i switch Guan Bi, is connected to ac bus by distributed generation unit i；Controller I gathers ac bus voltage v_L, distributed generation unit i output voltage v_oi, distributed generation unit i export electric current i_oi, distributed generation unit i H-bridge inverter circuit output electric current i_i, input grid-connected reactive power Q_g, through computing with Process, obtain the H-bridge inverter circuit duty cycle signals S of distributed generation unit i_i；S_iDrive H-bridge inverter circuit work Make, distributed generation unit i and distributed generation unit 1 islet operation in parallel；

(3) distributed generation unit controllers all in system are sent grid-connected synch command so that the electricity of each of which Pressure reference value is the most identical, and the rated capacity of the most each distributed generation unit is the most identical, its respective output voltage All tend to identical；

(4) grid-connected switch Guan Bi, all distributed generation unit send electric energy in addition to for load supplying, dump energy Being incorporated to AC network, this is the pattern of being incorporated into the power networks.

As shown in Figures 2 and 3, wherein, Fig. 2 is micro-capacitance sensor multi-inverter parallel control system method of work of the present invention The schematic flow sheet of controller 1 method of work of distributed generation unit 1 of the present invention, Fig. 3 is distributed of the present invention The schematic flow sheet of the controller i method of work of electric unit i.

In described method of work step (1), controller 1 computing obtains the H-bridge inverter circuit of distributed generation unit 1 Duty cycle signals S₁The step that is embodied as include:

A, controller 1 are according to line voltage v_g, grid-connected current i_gIt is calculated grid-connected reactive power Q_g, according to exchange Busbar voltage v_L, distributed generation unit 1 export electric current i_o1It is calculated distributed generation unit 1 and exports wattful power Rate P₁With output reactive power Q₁；

B, by grid-connected reactive power Q_g, distributed generation unit 1 active power of output P₁With output reactive power Q₁Meter Calculation obtains angular frequency variable quantityWith voltage magnitude variable quantity

$\left\{\begin{array}{c}{\widehat{\mathrm{\ω}}}_1=m_1\left({\stackrel{\‾}{P}}_1-P_1\right)+k_{d1}\frac{d}{dt}({\stackrel{\‾}{P}}_1-P_1)\\ {\hat{V}}_1=-n_1{Q}_1-k_{i1}\∫Q_{g}dt\end{array}\right.---\left(I\right)$

In formula I,For the rated generation amount of distributed generation unit 1, k_d1、k_i1It is respectively controller 1 power The differential coefficient controlled and integral coefficient, m₁And n₁For the sagging gain of controller 1, t is time variable；

C, to line voltage v_gSurvey calculation obtains controller 1 line voltage angular frequencyGrid voltage amplitude Electric network voltage phase angle θ_g；

D, by controller 1 line voltage angular frequencyGrid voltage amplitudeElectric network voltage phase angle θ_g, angular frequency Rate variable quantityVoltage magnitude variable quantitySynthesized reference voltage composite valueComputing formula is:

$v_{ref1}^{*}=({\stackrel{\‾}{V}}_1+{\hat{V}}_1)sin\[({\stackrel{\‾}{\mathrm{\ω}}}_1+{\widehat{\mathrm{\ω}}}_1)t+{\mathrm{\θ}}_g\]---\left(II\right);$

E, reference voltage composite valueDeduct distributed generation unit 1 and export electric current i_o1With the product of virtual impedance, Obtain voltage reference value v_ref1；

F, distributed generation unit 1 output voltage v_o1, voltage reference value v_ref1, distributed generation unit 1 export electricity Stream i_o1Regulate through Control of Voltage, obtain reference current

G, reference currentDistributed generation unit 1 output voltage v_o1, the H bridge inversion of distributed generation unit 1 Circuit output current i₁Control to adjust through electric current, obtain modulation wave signal D₁；Modulation wave signal D₁Carry out with triangular carrier PWM, obtains the H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁。

In described method of work step (2), controller i computing obtains the H-bridge inverter circuit of distributed generation unit i Duty cycle signals S_iThe step that is embodied as include:

H, controller i are according to ac bus voltage v_L, distributed generation unit i export electric current i_oiIt is calculated distribution Formula generator unit i active power of output P_iWith output reactive power Q_i；

I, by distributed generation unit i active power of output P_iWith output reactive power Q_i, grid-connected reactive power Q_gMeter Calculation obtains controller i angular frequency variable quantityWith voltage magnitude variable quantity

$\left\{\begin{array}{c}{\widehat{\mathrm{\ω}}}_i=m_i\left({\stackrel{\‾}{P}}_i-P_i\right)+k_{di}\frac{d}{dt}({\stackrel{\‾}{P}}_i-P_i)\\ {\hat{V}}_i=-n_i{Q}_i-k_{ii}\∫Q_{g}dt\end{array}\right.---\left(III\right)$

In formula III,For the rated generation amount of distributed generation unit i, k_di、k_iiIt is respectively controller i power The differential coefficient controlled and integral coefficient, m_iAnd n_iFor the sagging gain of controller i, t is time variable；

J, to ac bus voltage v_LSurvey calculation obtains controller i load voltage angular frequencyLoad voltage amplitudeLoad voltage phase angle θ_L；

K, by controller i angular frequency variable quantityVoltage magnitude variable quantityLoad voltage angular frequencyLoad Voltage magnitudeLoad voltage phase angle θ_LSynthetic controller i reference voltage composite valueComputing formula is:

$v_{refi}^{*}=({\stackrel{\‾}{V}}_L+{\hat{V}}_i)sin\[({\stackrel{\‾}{\mathrm{\ω}}}_L+{\widehat{\mathrm{\ω}}}_i)t+{\mathrm{\θ}}_L\]---\left(IV\right);$

L, controller i reference voltage composite valueDeduct distributed generation unit i and export electric current i_oiWith virtual impedance Product, obtain controller i voltage reference value v_refi；

M, distributed generation unit i output voltage v_oi, controller i voltage reference value v_refi, distributed generation unit i Output electric current i_oiRegulate through Control of Voltage, obtain reference current

N, reference currentDistributed generation unit i output voltage v_oi, the H bridge inversion of distributed generation unit i Circuit output current i_iControl to adjust through electric current, obtain modulation wave signal D_i；Modulation wave signal D_iCarry out with triangular carrier PWM, obtains the H-bridge inverter circuit duty cycle signals S of distributed generation unit i_i。

In described method of work step (3), distributed generation unit controllers all in system are sent grid-connected synchronization and orders Order so that the voltage reference value of each of which is the most identical, and final all distributed generation unit output voltages all tend to phase With, specific implementation method step is:

O, grid-connected synch command send, and distributed generation unit 1 middle controller 1 slowly regulates angular frequency in formula I Variable quantityWith voltage magnitude variable quantityThe two is gone to zero, then reference voltage composite value in formula II Taper to and line voltage v_gIdentical；

P, distributed generation unit 1 reference voltage composite valueChange makes its output voltage change, ac bus electricity Pressure v_LChange therewith；Meanwhile, distributed generation unit i middle controller i slowly regulates formula III middle controller i angle Frequency variationWith voltage magnitude variable quantityThe two is gone to zero, then formula IV middle controller i is with reference to electricity It is pressed into valueAlong with ac bus voltage v_LChange and change；Finally, all distributed power generations in system Unit output voltage is the most identical.

Utilize the implementation result of the micro-capacitance sensor Validation of Simulation Models present invention containing 2 distributed generation unit: electrical network is electric Pressure amplitude value virtual value is set to 230V, and the rated capacity of distributed generation unit 1 is 2kVA, distributed generation unit 2 Rated capacity is 1kVA, and load rating power is 176W, and the rated generation amount of distributed generation unit 1 is 800W, point The rated generation amount of cloth generator unit 2 is 400W.Fig. 4 show simulation data electric current design sketch, is divided into point in figure Cloth generator unit 1 independent operating, distributed generation unit 1 and 2 islet operation, grid-connected synchronization, it is incorporated into the power networks four The individual stage.0～3s, distributed generation unit 1 independent operating is load supplying；3～5s, distributed generation unit 2 Putting into, islet operation in parallel with distributed generation unit 1, is load supplying, due to two distributed generation unit jointly Rated capacity is than for 2:1, so the ratio of their output electric current is also 2:1；5s starts grid-connected synchronization, and rear entrance is also Net synchronous phase, now their output voltage is identical, so output electric current is the most identical；During 7s, grid-connected switch puts into, Distributed generation unit 1 and 2 parallel connection is incorporated into the power networks, and two distributed generation unit send electric energy in addition to for load supplying, Dump energy is incorporated to AC network.Simulation data electric current when Fig. 5 show two distributed generation unit parallel connection islet operations Enlarged drawing, Fig. 6 show simulation data Current amplifier figure when two distributed generation unit parallel connections are incorporated into the power networks.Two figures are all Indicate that distributed generation unit 1 exports electric current, distributed generation unit 2 exports electric current and grid-connected current, wherein, In Fig. 5, grid-connected current is zero.It can be seen that the present invention achieves preferable implementation result.

Claims (4)

1. a micro-capacitance sensor multi-inverter parallel control system, it is characterised in that include the distributed power generation of N number of parallel connection Unit, ac bus, load, low bandwidth communication, grid-connected switch, transformator, electrical network；Described distributed power generation list Unit is sequentially connected with is formed by micro-source, H-bridge inverter circuit, LC wave filter, switch, and each distributed generation unit also wraps Include its respective controller；The distributed generation unit of described N number of parallel connection exchanges mother by its respective switch with described Line connects, and described load is connected on described ac bus；Described grid-connected switch is connected with described ac bus, simultaneously It is sequentially connected with transformator, electrical network；Described low bandwidth communication by the controller 1 in distributed generation unit 1 and remaining Controller in N-1 distributed generation unit connects together；In described distributed generation unit 1, described control The Gather and input amount of device 1 has: line voltage v_g, grid-connected current i_g, ac bus voltage v_L, distributed generation unit 1 output voltage v_o1, distributed generation unit 1 export electric current i_o1, the H-bridge inverter circuit of distributed generation unit 1 Output electric current i₁, the output of described controller 1 has: the H-bridge inverter circuit dutycycle letter of distributed generation unit 1 Number S₁, grid-connected reactive power Q_g.For N-1 distributed generation unit of remaining in addition to distributed generation unit 1 For controller, its Gather and input amount and output are different from described controller 1, but this N-1 distributed power generation list Cell controller Gather and input amount is the most identical with output, in a distributed manner as a example by generator unit i, and 2≤i≤N, its controller I Gather and input amount has: ac bus voltage v_L, distributed generation unit i output voltage v_oi, distributed generation unit I exports electric current i_oi, distributed generation unit i H-bridge inverter circuit output electric current i_i, grid-connected reactive power Q_g, defeated Output has: the H-bridge inverter circuit duty cycle signals S of distributed generation unit i_i.Grid-connected reactive power Q_gBy described control Device 1 processed exports in described low bandwidth communication transmission to remaining N-1 distributed generation unit controller；

The method of work of micro-capacitance sensor multi-inverter parallel control system of the present invention, it is characterised in that concrete steps include:

(1) running initially in micro-capacitance sensor multi-inverter parallel control system, first distributed generation unit 1 breaker in middle closes Close, distributed generation unit 1 is connected to ac bus；In each sampling period starting point of controller 1, gather Line voltage v_g, grid-connected current i_g, ac bus voltage v_L, distributed generation unit 1 output voltage v_o1, distribution Formula generator unit 1 exports electric current i_o1, distributed generation unit 1 H-bridge inverter circuit output electric current i₁, and through fortune Calculate and process, obtain the H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁, grid-connected reactive power Q_g； S₁Driving H-bridge inverter circuit works, and distributed generation unit 1 is able to independent operating；

(2) distributed generation unit i switch Guan Bi, is connected to ac bus by distributed generation unit i；Controller I gathers ac bus voltage v_L, distributed generation unit i output voltage v_oi, distributed generation unit i export electric current i_oi, distributed generation unit i H-bridge inverter circuit output electric current i_i, input grid-connected reactive power Q_g, through computing with Process, obtain the H-bridge inverter circuit duty cycle signals S of distributed generation unit i_i；S_iDrive H-bridge inverter circuit work Make, distributed generation unit i and distributed generation unit 1 islet operation in parallel；

(3) distributed generation unit controllers all in system are sent grid-connected synch command so that the electricity of each of which Pressure reference value is the most identical, and the rated capacity of the most each distributed generation unit is the most identical, its respective output voltage All tend to identical；

(4) grid-connected switch Guan Bi, all distributed generation unit send electric energy in addition to for load supplying, dump energy Being incorporated to AC network, this is the pattern of being incorporated into the power networks.

The most according to claim 1, the method for work of control system, it is characterised in that in step (1), control Device 1 computing obtains the H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁Concrete steps include:

A, controller 1 are according to line voltage v_g, grid-connected current i_gIt is calculated grid-connected reactive power Q_g, according to exchange Busbar voltage v_L, distributed generation unit 1 export electric current i_o1It is calculated distributed generation unit 1 and exports wattful power Rate P₁With output reactive power Q₁；

B, by grid-connected reactive power Q_g, distributed generation unit 1 active power of output P₁With output reactive power Q₁Meter Calculation obtains angular frequency variable quantityWith voltage magnitude variable quantity

$\left\{\begin{array}{c}{\widehat{\mathrm{\ω}}}_1=m_1\left({\stackrel{\‾}{P}}_1-P_1\right)+k_{d1}\frac{d}{dt}({\stackrel{\‾}{P}}_1-P_1)\\ {\hat{V}}_1=-n_1{Q}_i-k_{i1}\∫Q_{g}dt\end{array}\right.---\left(I\right)$

In formula I,For the rated generation amount of distributed generation unit 1, k_d1、k_i1It is respectively controller 1 power The differential coefficient controlled and integral coefficient, m₁And n₁For the sagging gain of controller 1, t is time variable；

C, to line voltage v_gSurvey calculation obtains controller 1 line voltage angular frequencyGrid voltage amplitude Electric network voltage phase angle θ_g；

D, by controller 1 line voltage angular frequencyGrid voltage amplitudeElectric network voltage phase angle θ_g, angular frequency Rate variable quantityVoltage magnitude variable quantitySynthesized reference voltage composite valueComputing formula is:

$v_{ref1}^{*}=({\stackrel{\‾}{V}}_1+{\hat{V}}_1)sin\[({\stackrel{\‾}{\mathrm{\ω}}}_1+{\widehat{\mathrm{\ω}}}_1)t+{\mathrm{\θ}}_g\]---\left(II\right);$

E, reference voltage composite valueDeduct distributed generation unit 1 and export electric current i_o1With the product of virtual impedance, Obtain voltage reference value v_ref1；

F, distributed generation unit 1 output voltage v_o1, voltage reference value v_ref1, distributed generation unit 1 export electricity Stream i_o1Regulate through Control of Voltage, obtain reference current

G, reference currentDistributed generation unit 1 output voltage v_o1, distributed generation unit 1 H bridge inversion electricity Road output electric current i₁Control to adjust through electric current, obtain modulation wave signal D₁；Modulation wave signal D₁PWM is carried out with triangular carrier Modulation, obtains the H-bridge inverter circuit duty cycle signals S of distributed generation unit 1₁。

The most according to claim 1, the method for work of control system, it is characterised in that in step (2), control Device i computing obtains the H-bridge inverter circuit duty cycle signals S of distributed generation unit i_iConcrete steps include:

H, controller i are according to ac bus voltage v_L, distributed generation unit i export electric current i_oiIt is calculated distribution Formula generator unit i active power of output P_iWith output reactive power Q_i；

I, by distributed generation unit i active power of output P_iWith output reactive power Q_i, grid-connected reactive power Q_gMeter Calculation obtains controller i angular frequency variable quantityWith voltage magnitude variable quantity

$\left\{\begin{array}{c}{\widehat{\mathrm{\ω}}}_i=m_i\left({\stackrel{\‾}{P}}_i-P_i\right)+k_{di}\frac{d}{dt}({\stackrel{\‾}{P}}_i-P_i)\\ {\hat{V}}_i=-n_i{Q}_i-k_{ii}\∫Q_{g}dt\end{array}\right.---\left(III\right)$

In formula III,For the rated generation amount of distributed generation unit i, k_di、k_iiIt is respectively controller i power The differential coefficient controlled and integral coefficient, m_iAnd n_iFor the sagging gain of controller i, t is time variable；

J, to ac bus voltage v_LSurvey calculation obtains controller i load voltage angular frequencyLoad voltage amplitudeLoad voltage phase angle θ_L；

K, by controller i angular frequency variable quantityVoltage magnitude variable quantityLoad voltage angular frequencyLoad Voltage magnitudeLoad voltage phase angle θ_LSynthetic controller i reference voltage composite valueComputing formula is:

$v_{refi}^{*}=({\stackrel{\‾}{V}}_L+{\hat{V}}_i)sin\[({\stackrel{\‾}{\mathrm{\ω}}}_L+{\widehat{\mathrm{\ω}}}_i)t+{\mathrm{\θ}}_L\]---\left(IV\right);$

L, controller i reference voltage composite valueDeduct distributed generation unit i and export electric current i_oiWith virtual impedance Product, obtain controller i voltage reference value v_refi；

M, distributed generation unit i output voltage v_oi, controller i voltage reference value v_refi, distributed generation unit i Output electric current i_oiRegulate through Control of Voltage, obtain reference current

N, reference currentDistributed generation unit i output voltage v_oi, the H bridge inversion of distributed generation unit i Circuit output current i_iControl to adjust through electric current, obtain modulation wave signal D_i；Modulation wave signal D_iCarry out with triangular carrier PWM, obtains the H-bridge inverter circuit duty cycle signals S of distributed generation unit i_i。

The method of work of control system the most according to claim 1, it is characterised in that in step (3), to being In system, all distributed generation unit controllers send grid-connected synch command so that the voltage reference value of each of which all phases With, final all distributed generation unit output voltages all tend to identical, and specific implementation method is:

O, grid-connected synch command send, and distributed generation unit 1 middle controller 1 slowly regulates angular frequency in formula I Variable quantityWith voltage magnitude variable quantityThe two is gone to zero, then reference voltage composite value in formula II Taper to and line voltage v_gIdentical；

P, distributed generation unit 1 reference voltage composite valueChange makes its output voltage change, ac bus electricity Pressure v_LChange therewith；Meanwhile, distributed generation unit i middle controller i slowly regulates formula III middle controller i angle Frequency variationWith voltage magnitude variable quantityThe two is gone to zero, then formula IV middle controller i is with reference to electricity It is pressed into valueAlong with ac bus voltage v_LChange and change；Finally, all distributed power generations in system Unit output voltage is the most identical.