CN104935015B - Energy-storage system based on virtual synchronous inversion control - Google Patents

Abstract

The present invention relates to a kind of energy-storage system based on virtual synchronous inversion transformation technique, comprise battery, DC/DC changer, DC/AC changer, transformator, AC network, the first controller and second controller.The present invention uses virtual synchronous electric machines control technology, makes the external characteristics of the exchange interface of the energy storage device of band power electronic system can be equivalent to synchronous motor characteristic, thus improves inertia and the damping characteristic of power electronics energy-storage system, strengthens the stability of power system.

Description

Energy-storage system based on virtual synchronous inversion control

Technical field

The present invention relates to intelligent grid, a kind of energy-storage system based on virtual synchronous inversion control.

Background technology

Because power electronic equipment is almost without rotary inertia and damping characteristic, so considering energy-storage system from two kinds of angles The problem of discharge and recharge.

From the point of view of electrical network, set up and improve a kind of electrical network form intelligence more friendly to generation of electricity by new energy Electrical network, it is possible to the problem solving generation of electricity by new energy well.Topmost two features of intelligent grid are exactly intelligent and big rule Mould utilizes regenerative resource.In following intelligent grid, AC network is as the main power transmission mode of power system, direct current transportation As the useful supplement that ac transmission is important.Compared to AC network, direct current network is more friendly to generation of electricity by new energy.Small-sized The place concentrated of distributed power generation (referring mainly to wind-power electricity generation and photovoltaic generation) small-sized DC distribution net can be set up, finally It is incorporated to large-scale ac transmission network after unified inversion.Due to the access of extensive new forms of energy equipment, energy storage device is also following intelligence The necessaries that energy electrical network is indispensable.Building intelligent grid is the essential measure solving new energy power generation grid-connection.

From the point of view of inverter, the transformation of AC network and development occur in that another kind of thinking.Tradition bulk power grid TRT (thermal power generation, hydroelectric generation etc.) be manufactured almost exclusively by synchronous generator generating, if the inverter in distribution from Looking and can present the operation characteristic of synchronous generator in net side, then just can be the most compatible with tradition electrical network.For this reason, it may be necessary to Inverter is transformed so that it is as viewed from net side, present the characteristic of synchronous generator, thus the stability of electrical network of increasing exchanges.

Virtual synchronous inversion controlling method based on energy-storage system, according to the electromagnet inertia of synchronous generator, to inverter It is controlled, more can reflect the characteristic of synchronous generator.Simulate the electromagnetic property of synchronous generator in controller, rotor is used to Property, primary frequency modulation and excitation voltage adjustment characteristic, more can simulate the characteristic of synchronous generator from external characteristics, and due to idle, have There is integral element in power control part, can realize idle, meritorious indifference and control, and can be substantially improved system stability.

Summary of the invention

It is an object of the invention to provide a kind of energy-storage system based on virtual synchronous inversion control, this system is filled at battery During electricity, inverter uses the control strategy of virtual synchronous inversion transformation technique, can improve inertia and the damping characteristic of system, strengthens system Stability.

The technical solution of the present invention is as follows:

A kind of energy-storage system based on virtual synchronous inversion control, its feature is, comprise battery, DC/DC changer, DC/AC changer, transformator, AC network, the first controller and second controller；

Described battery is connected with the input of DC/DC changer, and the outfan of described DC/DC changer is with described The input of DC/AC changer is connected, and the outfan of this DC/AC changer is connected with the low pressure, input end of described transformator, The high-voltage output end of described transformator is connected with AC network；

The outfan of the first described controller is connected with the control end of described DC/DC changer, the first controller Input is connected with the outfan of DC/DC changer, the outfan of described second controller and the control end of DC/AC changer Being connected, the input of second controller is connected with the outfan of described DC/AC changer；

The first described controller includes the first comparator and a PI controller, the output of this first comparator termination the The input of one PI controller；

Described second controller includes that virtual synchronous inversion control, power control, electric current controls, voltage coordinate modulus of conversion Block, electric current coordinate transferring and inverse coordinate transferring six part, described virtual synchronous inversion control part includes machinery Partly, excitation system, angular transition module and electric part；

Described mechanical part outfan connects the input of described angular transition module respectively and described inverse coordinate turns The input of die change block, the outfan of described angular transition module connects the input of described voltage coordinate modular converter respectively With the input of electric current coordinate transferring, electric part defeated described in output termination of described voltage coordinate modular converter Enter end, the input of the electric part described in output termination of described excitation system, the output termination of described electric part The input that described electric current controls, the input that the electric current described in output termination that described power controls controls, described electricity The input of the inverse coordinate transferring described in output termination of flow control；

The second comparator that described mechanical part includes being sequentially connected with, the 3rd comparator, hypothetical rotor inertial element, One adder and first integrator, the outfan of described hypothetical rotor inertial element connects described second through adjusting difference feedback element Second input of comparator；

Described excitation system includes the 4th comparator, virtual magnetizing exciter and the first compensator, described virtual magnetizing exciter Outfan connect the second input of the 4th comparator through the first described compensator；

Described power control section is divided and is included that the 5th comparator and the 2nd PI controller, the 6th comparator and the 3rd PI control Device；

Described current control division divides and includes that d axle component controls and q axle component controls, and described d axle component controls to include Second adder, the 7th comparator and the 4th PI controller, described q axle component controls to include the 3rd adder, the 8th compares Device and the 5th PI controller.

The first described controller and second controller are digital signal processor, single-chip microcomputer or computer.

Described DC/DC changer is high-power, the DC converter of wide output voltage range.

Described DC/AC changer is to use virtual synchronous inversion control and conventional power to control the Comprehensive Control combined The direct current of algorithm becomes the changer of exchange, it is achieved whole energy-storage system is equivalent in terms of net side the mesh of a synchronous generator , the voltage of responsive electricity grid and frequency disturbance adaptively, strengthen inertial properties and the damping characteristic of system.

The control method of the energy-storage system based on virtual synchronous inversion control described in utilization, its feature is, the method Including following content and step:

1) initialize, by operator according to the system requirements following parameter value of setting in this energy-storage system:

The DC bus-bar voltage reference value of DC/AC changer

Electromagnetic power reference value P of energy-storage system_ref；

Reactive power reference qref Q of energy-storage system_ref；

Set difference coefficient R as between 30-50, inertia constant M as between 1-20, load-damping constant D as 1% or 2%；

Set hypothetical rotor x_qImpedance x with stator_dIt is between 1-10；

AC voltage reference value U_ref, per unit value is set to 1；

Set the gain K of the first compensator of excitation system_fWith time constant T_fBetween 0-1, the gain K of excitation system_a Between 100-500, excitation system time constant T_eBetween 0-1, upper limit E of excitation voltage amplitude_fmax0-15 it Between, the lower limit E of excitation voltage amplitude_fmin=-E_fmax；

Set the hypothetical rotor transient state impedance x ' of electric part_dSpan between 0.1-0.5, the resistance of the transient state of stator Anti-x '_qSpan between 0.3-1, the transient state open circuit time constant T ' of d axle_doSpan between 1.5-10, q axle Transient state open circuit time constant T '_qoSpan between 0.5-2.0；

The control coefrficient of the oneth PI controller is k_p1And k_i1, 0 < k_p1< 1000,0 < k_i1<1000；

The control coefrficient of the 2nd PI controller is k_p2And k_i2, 0 < k_p2< 1000,0 < k_i2<1000；

The control coefrficient of the 3rd PI controller is k_p3And k_i3, 0 < k_p3< 1000,0 < k_i3<1000；

The control coefrficient of the 4th PI controller is k_p4And k_i4, 0 < k_p4< 1000,0 < k_i4<1000；

The control coefrficient of the 5th PI controller is k_p5And k_i5, 0 < k_p5< 1000,0 < k_i5<1000；

Use Hall element that DC voltage, AC voltage and current are sampled, obtain DC/DC changer (2) output end voltage U_dc, unit is per unit value, and grid side three-phase voltage e_a, e_b, e_cWith grid side three-phase current i_a, i_b, i_c；

2), the first controller performs according to the following steps:

21), the input value of the first comparator calculating the oneth PI controller:

22), a PI controller calculate after the output receiving above-mentioned first comparator, output is corresponding to be controlled Amount:

3) mechanical part of the virtual synchronous inversion control of second controller (7) performs according to the following steps:

31), virtual machine power P is calculated by the second comparator by following equation_m:

$P_m=P_{ref}-\frac{1}{R}\mathrm{\&Delta;}\mathrm{\&omega;},$

Wherein, P_refBeing the electromagnetic power reference value set, R is difference coefficient, and Δ ω is hypothetical rotor offsetFor the output of hypothetical rotor inertial element, M is the inertia constant in hypothetical rotor inertial element, and D is empty Intending the load-damping constant in rotor inertia link, s is complex frequency, and the initial value of Δ ω is set to zero；

32), by virtual accelerating power P of the 3rd comparator calculating machine part_a:

P_a=P_m-P_e, wherein P_eFor the electromagnetic power of mechanical part, P_e=e_ai_a+e_bi_b+e_ci_c；

33), calculating angular velocity by first adder is: ω=ω₀+ Δ ω, ω₀For the initial value of angular velocity, work as electrical network Frequency is 50Hz, then ω₀=2 × π × 50=314rad/s；

34), by first integrator calculating synchronization angle: θ=∫ ω；θ is the input of angular transition module；

35), carrying out angle compensation by angular transition module, formula is as follows:

$tan\left({\mathrm{\&theta;}}_0\right)=\frac{x_{q}I}{e_g}$

${\mathrm{\&theta;}}^{\&prime;}=\mathrm{\&theta;}-(\frac{\mathrm{\&pi;}}{2}-{\mathrm{\&theta;}}_0)$

Wherein, θ ' is phase-locked angle；I is power network current amplitude；e_gFor grid voltage amplitude；x_qFor hypothetical rotor impedance；

4), the excitation system of second controller virtual synchronous inversion control performs according to the following steps:

41) input quantity U of virtual magnetizing exciter, is calculated by the 4th comparator_t, formula is as follows:

U_t=U_ref-U_x

Wherein: U_refFor the AC magnitude of voltage set, K_fAnd T_fIt is gain and the time constant of the first compensator；U_xIt is The output of one compensator；

42) the input virtual excitation voltage E of electric part, is calculated by virtual magnetizing exciter_f, formula is as follows:

$E_f=\frac{K_a}{T_{e}s+1}{U}_t,$

Wherein: K_aAnd T_eIt is respectively gain and time constant, the E of virtual magnetizing exciter_fmaxAnd E_fminIt is respectively virtual magnetizing exciter The upper and lower bound of voltage magnitude；

43), U is calculated by the first compensator_x, formula is as follows:

$U_x=\frac{{\mathrm{sK}}_f}{T_{f}s+1}{E}_f.$

5), voltage coordinate conversion module and electric current coordinate transformation module perform according to the following steps:

51), by e_a、e_bAnd e_cLine voltage d-q component U is calculated through voltage coordinate conversion module_dAnd U_q, formula is as follows:

$\left[\begin{array}{c}{U}_d\\ U_q\end{array}\right]=\frac{\sqrt{2}}{\sqrt{3}}\left[\begin{array}{ccc}cos\mathrm{\&theta;}& cos(\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& cos(\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;}\\ -sin\mathrm{\&theta;}& -\sin (\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& -\sin (\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})\end{array}\right]\left[\begin{array}{c}{e}_a\\ e_b\\ e_c\end{array}\right]$

52), by i_a、i_bAnd i_cLine voltage d-q component i is calculated through electric current coordinate transformation module_dAnd i_q, formula is as follows:

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\frac{\sqrt{2}}{\sqrt{3}}\left[\begin{array}{ccc}cos\mathrm{\&theta;}& cos(\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& cos(\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;}\\ -sin\mathrm{\&theta;}& -\sin (\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& -\sin (\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

6), the electric part of second controller virtual synchronous inversion control performs according to the following steps:

61), calculating current is with reference to I_dref1And I_qref1, formula is as follows:

$I_{dref1}=\frac{E_f-(T_{d0}^{\&prime;}s+1)U_q}{x_d^{\&prime;}{T}_{d0}^{\&prime;}s+x_d}$

$I_{qref1}=\frac{(T_{q0}^{\&prime;}s+1)U_d}{x_q^{\&prime;}{T}_{q0}^{\&prime;}s+x_q}$

Wherein: U_dAnd U_qIt it is the d-q component of line voltage；I_dref1And I_qref1It it is described DC/AC changer (3) output electricity The virtual stator current part of stream, E_fIt it is virtual excitation voltage；

7), second controller power control section divide according to the following steps perform:

71) input of the 2nd PI controller: P, is calculated by the 5th comparator_ref-P_e；

72), the 2nd PI controller after the output receiving above-mentioned 5th comparator, be controlled computing, output is corresponding Controlled quentity controlled variable I_dref2: I_dref2=k_p2(P_ref-P_e)+k_i2∫(P_ref-P_e)dt；It is the input that current control division divides；

73) input of the 3rd PI controller: Q, is calculated by the 6th comparator_ref-Q_e；

74), the 3rd PI controller after the output receiving above-mentioned 6th comparator, be controlled computing, output is corresponding Controlled quentity controlled variable I_qref2:

I_qref2=k_p3(Q_ref-Q_e)+k_i3∫(Q_ref-Q_e)dt；It is the input that current control division divides；

8) the d axle component that, second controller (7) current control division divides controls to perform according to the following steps:

81) d shaft current reference value I, is calculated_dref, formula is as follows:

I_dref=I_dref1+I_dref2；

82) input of the 4th PI controller: I, is calculated by the 7th comparator_dref-I_d；I_dDivide for three-phase current d axle Amount, by i_a、i_bAnd i_cExport through coordinate transform；

83), the 4th PI controller after the output receiving above-mentioned 7th comparator, be controlled computing, output is corresponding Obtain controlled quentity controlled variable U_dref: U_dref=k_p4(I_dref-I_d)+k_i4∫(I_dref-I_d)dt；

9) the q axle component that, second controller current control division divides controls to perform according to the following steps:

91) q shaft current reference value I, is calculated_qref, formula is as follows:

I_qref=I_qref1+I_qref2；

92) input of the 5th PI controller: I, is calculated by the 8th comparator_qref-I_q；I_qDivide for three-phase current q axle Amount, by i_a、i_bAnd i_cExport through coordinate transform；

93), the 5th PI controller after the output receiving above-mentioned 8th comparator, be controlled computing, export mutually deserved Controlled quentity controlled variable U_qref: U_qref=k_p5(I_qref-I_q)+k_i5∫(I_qref-I_q)dt；

10), second controller output:

101), the U that will be obtained_drefAnd U_qrefConvert through inverse coordinate transformation module, obtain U_aref、U_brefAnd U_crefThree tune Ripple processed, using these three amount as control signal with carrier wave ratio relatively, it is thus achieved that the control signal of DC/AC changer (3), formula is as follows:

$\left[\begin{array}{c}{U}_{aref}\\ U_{bref}\\ U_{cref}\end{array}\right]=\frac{\sqrt{2}}{\sqrt{3}}\left[\begin{array}{cc}cos\mathrm{\&theta;}& -sin\mathrm{\&theta;}\\ cos(\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& -\sin (\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})\\ cos(\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})& -\sin (\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})\end{array}\right]\left[\begin{array}{c}{U}_{dref}\\ U_{qref}\end{array}\right].$

The technique effect of the present invention is as follows:

In present system, and the DC/AC inverter of grid side connection uses the control method of virtual synchronous inversion transformation technique, The frequency necessary to electrical network supports and voltage support, improves the stability of system.Its feature is as follows:

1, it is equivalent to synchronous generator characteristic due to the external characteristics of power electronic system exchange interface so that accumulator charge and discharge It is mutual that electrical interface equipment can participate in electrical network, provides necessary support to line voltage and frequency, can improve grid stability.

2. use and there is high power transmission ability, wide output voltage range DC/DC changer, the sound of system can be improved Answer speed and control accuracy.

Accompanying drawing explanation

Fig. 1 is the entire block diagram of present invention energy-storage system based on virtual synchronous inversion transformation technique.

Fig. 2 is virtual synchronous inversion control entirety control block diagram.

Fig. 3 is mechanical part control block diagram.

Fig. 4 is Excitation Controller block diagram.

Fig. 5 is the first controller control block diagram.

Fig. 6 is second controller power control block figure.

Fig. 7 is second controller electric current control block diagram.

Fig. 8 is angular transition module

Fig. 9 is system control process figure.

Detailed description of the invention

Below in conjunction with embodiment and accompanying drawing, the invention will be further described, and nitrogen should not limit the protection model of the present invention with this Enclose.

Referring to Fig. 1, Fig. 1 is present invention energy-storage system based on virtual synchronous inversion transformation technique schematic diagram, comprise battery 1, DC/DC changer 2, DC/AC changer 3, transformator 4, AC network the 5, first controller 6 and second controller 7, in detailed below Introduce each ingredient:

Described battery 1 is to provide energy storage and the equipment of energy output for energy-storage system；

DC/DC changer 2 is high-power, the changer of wide output voltage range；

It is comprehensive that DC/AC changer 3 uses that the control method of virtual synchronous inversion transformation technique and conventional power control to combine Control algolithm, it is achieved in terms of net side, whole energy-storage system is equivalent to the purpose of a synchronous generator, responds electricity adaptively The voltage of net and frequency disturbance, strengthen inertial properties and the damping characteristic of system.

First controller 6 is responsible for the sampling of DC/DC changer 2, is processed, calculates and control etc.；

Second controller 7 is responsible for data sampling, is processed, calculates and control etc., controls the DC/AC changer 3 of net side System.

Described battery 1 is connected with the input of DC/DC changer 2, the outfan of described DC/DC changer 2 and institute The input of the DC/AC changer 3 stated is connected, the outfan of this DC/AC changer 3 and the low pressure input of described transformator 4 End is connected, and the high-voltage output end of described transformator 4 is connected with AC network 5；

The outfan of the first described controller 6 is connected with the control end of described DC/DC changer 2, the first controller 6 Input be connected with the outfan of DC/DC changer 2, the outfan of described second controller 7 and DC/AC changer 3 Controlling end to be connected, the input of second controller 7 is connected with the outfan of described DC/AC changer 3.

Fig. 2 is the control block diagram of the first controller 6, and the first described controller 6 includes the first comparator and PI control Device processed, the input of output termination the oneth PI controller of this first comparator.

Described second controller 7 includes that virtual synchronous inversion control, power control, electric current controls, voltage coordinate conversion Module, electric current coordinate transferring and inverse coordinate transferring six part, described virtual synchronous inversion control part includes machine Tool part, excitation system, angular transition module and electric part；

Described mechanical part outfan connects the input of described angular transition module respectively and described inverse coordinate turns The input of die change block, the outfan of described angular transition module connects the input of described voltage coordinate modular converter respectively With the input of electric current coordinate transferring, electric part defeated described in output termination of described voltage coordinate modular converter Enter end, the input of the electric part described in output termination of described excitation system, the output termination of described electric part The input that described electric current controls, the input that the electric current described in output termination that described power controls controls, described electricity The input of the inverse coordinate transferring described in output termination of flow control；

The second comparator that described mechanical part includes being sequentially connected with, the 3rd comparator, hypothetical rotor inertial element, One adder and first integrator, the outfan of described hypothetical rotor inertial element connects described second through adjusting difference feedback element Second input of comparator；

Described excitation system includes the 4th comparator, virtual magnetizing exciter and the first compensator, described virtual magnetizing exciter Outfan connect the second input of the 4th comparator through the first described compensator；

Described power control section is divided and is included that the 5th comparator and the 2nd PI controller, the 6th comparator and the 3rd PI control Device；

Described current control division divides and includes that d axle component controls and q axle component controls, and described d axle component controls to include Second adder, the 7th comparator and the 4th PI controller, described q axle component controls to include the 3rd adder, the 8th compares Device and the 5th PI controller.

Fig. 3 is virtual synchronous inversion control entirety control block diagram, and Fig. 4 is mechanical part control block diagram, and Fig. 5 is virtual synchronous The exciter control system of inversion controlling method, Fig. 6 is the power control block figure of second controller 7, and Fig. 7 is the electricity of second controller Flow control block diagram, Fig. 8 is angular transition module diagram, and Fig. 9 is the overall control flow chart of present system.Fig. 4, Fig. 5, figure 6 and Fig. 7 are included in Fig. 3.

Claims (3)

1. an energy-storage system based on virtual synchronous inversion control, it is characterised in that comprise battery (1), DC/DC changer (2), DC/AC changer (3), transformator (4), AC network (5), the first controller (6) and second controller (7):

Described battery (1) is connected with the input of DC/DC changer (2), the outfan of described DC/DC changer (2) with The input of described DC/AC changer (3) is connected, the outfan of this DC/AC changer (3) and described transformator (4) Low pressure, input end is connected, and the high-voltage output end of described transformator (4) is connected with AC network (5)；

The outfan of described the first controller (6) is connected with the control end of described DC/DC changer (2), the first controller (6) input is connected with the outfan of DC/DC changer (2), and the outfan of described second controller (7) becomes with DC/AC The control end of parallel operation (3) is connected, and the input of second controller (7) is connected with the outfan of described DC/AC changer (3)；

Described the first controller (6) includes the first comparator and a PI controller, the output of this first comparator termination the The input of one PI controller；

Described second controller (7) includes that virtual synchronous inversion control, power control, electric current controls, voltage coordinate modulus of conversion Block, electric current coordinate transferring and inverse coordinate transferring six part, described virtual synchronous inversion control part includes machinery Partly, excitation system, angular transition module and electric part；

Described mechanical part outfan connects the input of described angular transition module and described inverse Coordinate Conversion mould respectively The input of block, the outfan of described angular transition module connects input and the electricity of described voltage coordinate modular converter respectively The input of stream coordinate transferring, the input of the electric part described in output termination of described voltage coordinate modular converter End, the input of the electric part described in output termination of described excitation system, the output of described electric part terminates institute State the input that electric current controls, the input that the electric current described in output termination that described power controls controls, described electric current The input of the inverse coordinate transferring described in output termination controlled；

Described mechanical part includes the second comparator being sequentially connected with, the 3rd comparator, hypothetical rotor inertial element, first adds Musical instruments used in a Buddhist or Taoist mass and first integrator, the outfan of described hypothetical rotor inertial element compares through adjusting difference feedback element to connect described second Second input of device；

Described excitation system includes the 4th comparator, virtual magnetizing exciter and the first compensator, described virtual magnetizing exciter defeated Go out end and connect the second input of the 4th comparator through the first described compensator；

Described power control section is divided and is included the 5th comparator and the 2nd PI controller, the 6th comparator and the 3rd PI controller；

Described current control division divides and includes that d axle component controls and q axle component controls, and described d axle component controls to include second Adder, the 7th comparator and the 4th PI controller, described q axle component control to include the 3rd adder, the 8th comparator and 5th PI controller.

Energy-storage system based on virtual synchronous inversion control the most according to claim 1, it is characterised in that described first Controller (6) and second controller (7) are digital signal processor, single-chip microcomputer or computer.

Energy-storage system based on virtual synchronous inversion control the most according to claim 1, it is characterised in that described DC/ AC changer (3) is that the direct current of the comprehensive controling algorithm using virtual synchronous inversion control and conventional power to control to combine becomes friendship The changer of stream, it is achieved in terms of net side, whole energy-storage system is equivalent to the purpose of a synchronous generator, responds adaptively The voltage of electrical network and frequency disturbance, strengthen inertial properties and the damping characteristic of system.