CN102638038A - Parallel charging and discharging power conversion system - Google Patents

Abstract

A parallel charging and discharging power conversion system belongs to electric electronics and electric automatic equipment and solves the problems of low capacity and information transmission reliability and difficulty in coordination control of an existing parallel-connection charging and discharging power conversion system. The parallel charging and discharging power conversion system comprises an upper computer, a centralized control unit and N subsystems. Each subsystem comprises an isolation transformer, a bi-directional alternating-current and direct-current converter, a bi-directional direct-current converter, a battery pack and a controller, the isolation transformers are connected with alternating-current buses, the upper computers are connected with the centralized control units through communication cables, and the centralized control units are respectively communicated with the controllers of the subsystems through the communication network and optical fibers. By the aid of a layering control structure, the parallel-connection charging and discharging power conversion system is high in system capacity and information transmission reliability and high in speed and has charging and discharging characteristics applicable to high-capacity battery packs, and accordingly grid-tied running and parallel-connection islet running of the subsystems and seamless conversion between the two running modes are realized, and the parallel-connection charging and discharging power conversion system is applicable to an energy storage system with a high-capacity battery pack.

Description

A kind of parallel connection discharges and recharges power conversion system

Technical field

The invention belongs to power electronics and Electric Power Automation Equipment, be specifically related to a kind of parallel connection and discharge and recharge power conversion system.

Background technology

Influence becomes clear day by day the peak-valley difference that urban distribution network enlarges day by day to power grid security with the distributed intermittent regenerative resource of being on the increase.Simultaneously, more and more enterprises needs the higher quality of power supply to improve the qualification rate of its product; Department such as hospital, government then relies on jumbo stand-by power supply so that the emergency service of critical load to be provided.The solution of these problems all depends on the development of energy storage technology.Cycle efficieny height, change working are fast, less demanding, the geographical adaptable characteristics of power plant construction land used receive much concern owing to having for battery energy storage.The battery energy storage station construction period lacks, is easy to expand, and does not have high temperature, high pressure, high rotating speed equipment and complicated auxiliary system in standing, and operation expense is low, and reliability and fail safe are higher.At present, China carries out extensive battery energy storage Study on Technology just energetically, explores the safe and stable operation pattern at battery charging and discharging station, in the hope of improve the comprehensive economy of battery energy storage power station comprehensively, supports the fast development of strong intelligent grid.

Along with the rise of battery energy storage technology, converting means and the relative control technologies supporting with energy-storage system have also obtained significant progress.Existing parallel connection discharges and recharges power conversion system and adopts centralized control, principal and subordinate's control, distributed logic control usually and do not have interconnection line control; That yet this type of controlling schemes can't provide is highly reliable, the message transmission approach of two-forty, generally only is applicable to the parallel system that the module spatial distribution is less.And existing parallel connection discharges and recharges power conversion system and generally is made up of a plurality of subsystems; The battery of each subsystem is by the parallelly connected again battery pack that constitutes after a plurality of battery cell series connection; The group difference of this type of battery pack is bigger, and is more strict to discharging and recharging control and the requirement of energy scheduling strategy.

Companies such as external ABB, DynaPower, Exergonix are devoted for years in the powerful energy conversion system of research and development; PCS100 ESS series energy storage converter device like ABB AB's research and development; System power can reach 5MW, but it adopts single step arrangement, can not adapt to battery terminal voltage on a large scale; This just determines that the battery types of its utilization is limited, and also higher to the characteristic requirements of battery pack.Therefore, be necessary to seek a kind of new power conversion system and control method.

Summary of the invention

The present invention proposes a kind of parallel connection and discharges and recharges power conversion system, solves existing parallel connection and discharges and recharges the problem that the power conversion system capacity is little, the message transmission reliability is low, difficulty is controlled in coordination, to realize the reliable and stable operation of high-power parallel system.

A kind of parallel connection of the present invention discharges and recharges power conversion system, comprises host computer, central control unit and N sub-systems, and each subsystem structure is identical, includes isolating transformer, two-way alternating current-direct current current transformer, bidirectional, dc current transformer, battery pack and controller; The isolating transformer of each subsystem links to each other with ac bus, and ac bus is connected to electrical network or is connected to local load through local switch through the switch that is incorporated into the power networks; Said host computer is connected with central control unit through communication cable, central control unit pass through communication network and optical fiber respectively with the controller communication of each subsystem, N=1～10 is characterized in that:

(1) said host computer, through the RS485 communications protocol to central control unit transmit operation instruction, pattern input variable j, active power value P _RefWith reactive power value Q _Ref, said operational order comprises startup and shutdown; The value of said pattern input variable j is 1 or 2; When receiving the electric network fault signal of central control unit transmission through optical fiber, make pattern input variable j=1;

(2) said central control unit, carry out following operation:

(1) pattern determining step:

(1.1) put control model variable m=0, whether the decision operation instruction is shutdown, is then to close central control unit; Otherwise periodically whether judgment model input variable j equals control model variable m, is rotor step (1.2) then, otherwise rotor step (1.3);

(1.2) if m=1 changes step (3); Otherwise change step (2);

(1.3) putting m=j, judge whether m=1, is then to change step (5); Otherwise change step (4);

(2) step that is incorporated into the power networks comprises sub-steps:

(2.1) line voltage is detected with locking obtain electrical network amplitude V mutually _g, synchronizing signal θ and mains frequency f _g

(2.2) electric network state is judged:

Judge whether 264.4V≤V _g≤342.1V and 49.5Hz≤f _g≤50.5Hz is that then electrical network is a normal condition, and the closure switch that is incorporated into the power networks sends control model variable m=2, rotor step (2.3) through optical fiber to each subsystem; Otherwise electrical network is a malfunction, sends the electric network fault signal to host computer, changes step (1);

(2.3) the active power value P of wait host computer _RefWith reactive power value Q _Ref, calculate the active power reference value P of each subsystem _RefiWith reactive power reference qref Q _Refi:

$P_{\mathrm{refi}}=\frac{P_{\mathrm{ref}}\·k_i\·{\mathrm{SOC}}_i}{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{k}_x\·{\mathrm{SOC}}_x},$ $Q_{\mathrm{refi}}=\frac{Q_{\mathrm{ref}}}{N};$

Wherein, SOC _iBe i subsystem battery pack state-of-charge, k _iBe SOC _iThe weights coefficient, k _i, k _xSpan is 0～1,

(2.4) send synchronizing signal and corresponding active power reference value P to each subsystem controller _RefiWith reactive power reference qref Q _Refi, rotor step (2.1);

(3) islet operation step comprises sub-steps:

(3.1) break off the switch that is incorporated into the power networks, send control model variable m=1 to each subsystem through optical fiber; Utilize counter to obtain the initial synchronisation signal

X is the current time count value, and X=mod (10 ⁶/ 2 ^T), mod representes the value in the bracket is rounded, and T is 0～7 integer, counter per 20 * 2 ^TNs adds 1;

(3.2) the active power P that exports according to each subsystem _i, reactive power Q _iWith battery pack state-of-charge SOC _iCalculate the active power reference value P of each subsystem _RefiWith reactive power reference qref Q _Refi: $P_{\mathrm{Refi}}=\frac{k_i\·{\mathrm{SOC}}_i\·\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{P}_x}{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{k}_x\·{\mathrm{SOC}}_x},$ $Q_{\mathrm{Refi}}=\frac{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{Q}_x}{N};$

(3.3) send initial synchronisation signal, corresponding active power reference value P to each subsystem controller _Refi, reactive power reference qref Q _RefiWith initial output voltage amplitude V _Mrefo=311V, rotor step (3.1);

(4) isolated island comprises sub-steps to the switch step that is incorporated into the power networks:

(4.1) line voltage is detected with locking obtain electrical network amplitude V mutually _g, synchronizing signal θ and mains frequency f _g

(4.2) electric network state is judged:

Judge whether 264.4V≤V _g≤342.1V and 49.5Hz≤f _g≤50.5Hz is that then electrical network is a normal condition, rotor step (4.3); Otherwise electrical network is a malfunction, sends the electric network fault signal to host computer, changes step (1);

(4.3) put the initial synchronisation signal

Put initial output voltage amplitude V _Mrefo=V _g

(4.4) the closure switch that is incorporated into the power networks, and send control model variable m=2 to each subsystem through optical fiber;

(4.5) send synchronizing signal θ and corresponding active power reference value P to each subsystem controller _Refi=0 with reactive power reference qref Q _Refi=0;

(5) be incorporated into the power networks to the isolated island switch step, comprise sub-steps:

(5.1) detect the active power P that parallel connection discharges and recharges power conversion system output _gAnd reactive power Q _g

(5.2) break off the switch that is incorporated into the power networks, and send control model variable m=1, initial output voltage amplitude V to each subsystem through optical fiber _Mrefo=311V, initial synchronisation signal

The active power reference value

And reactive power reference qref

(3) said each subsystem all has the bidirectional, dc current transformer; In each subsystem; Isolating transformer connects two-way alternating current-direct current current transformer through switch, and two-way alternating current-direct current current transformer connects the bidirectional, dc current transformer through dc bus, and the bidirectional, dc current transformer links to each other with battery pack; Controller generates the first～the six tunnel drive signal and delivers to two-way alternating current-direct current current transformer, and controller generates the 7th, the octuple drive signal is delivered to the bidirectional, dc current transformer;

A. the controller of i sub-systems comprises pattern judge module, islet operation module, module is incorporated into the power networks; I=1～N;

(1) the pattern judge module carries out following operation:

(1.1) put mode of operation variable n=0, put output voltage frequency f _i=50Hz;

(1.2) periodically judge whether control model variable m equals work at present pattern variable n, and being then changes step (1.4); Otherwise change step (1.3);

(1.3) value of control model variable m is composed to mode of operation variable n;

(1.4) mode of operation variable n is judged:

N=1 changes (2) islet operation module;

N=2 changes (3) module that is incorporated into the power networks;

(2) the islet operation module is carried out following operation:

(2.1) to the initial three-phase alternating voltage u of ac bus _{Sa, b, ci}, initial three-phase alternating current i _{Sa, b, ci}And initial DC bus-bar voltage u _Sdci, initial cell voltage u _SbatiWith the initial cells current i _SbatiCarry out filtering, obtain three-phase alternating voltage u _{A, b, ci}, three-phase alternating current i _{A, b, ci}, DC bus-bar voltage u _Dci, battery voltage u _Bati, output battery pack current i _Bati

(2.2) synchronizing signal of central control unit being sent is advanced horizontal lock, obtains initial phase angle

(2.3) calculate phase angle

(2.4) utilize phase angle Carry out the coordinate system conversion, with three-phase alternating voltage u under the three phase static coordinate system _{A, b, ci}, three-phase alternating current i _{A, b, ci}Be transformed to and exchange active voltage u under the synchronous rotating frame _Di, exchange reactive voltage u _Qi, exchange active current i _Di, exchange reactive current i _Qi

Calculate the active power of output P of this subsystem _iAnd reactive power Q _i:

P _i＝u _dii _di+u _qii _qi，Q _i＝-u _dii _qi+u _qii _di，

With u _{A, b, ci}, i _{A, b, ci}, u _Dci, u _Bati, i _BatiDeliver to said central control unit through communication network, with P _iAnd Q _iDeliver to said central control unit through optical fiber;

(2.5) calculate the active power error e _Pi: e _Pi=P _Refi-P _iWherein, P _RefiThe active power reference value of the i sub-systems that provides for central control unit;

(2.6) calculate output voltage frequency f _i: f _i=50+K _Fpe _Pi+ K _Fi∫ e _PiDt; Wherein, 3.73 * 10 ^-3≤frequency adjustment proportionality coefficient K _Fp≤4.32 * 10 ^-3, 1.12 * 10 ^-3≤frequency adjustment integral coefficient K _Fi≤1.56 * 10 ^-3

(2.7) calculate the reactive power error e _Qi: e _Qi=Q _Refi-Q _iWherein, Q _RefiThe reactive power reference qref of the i sub-systems that provides for central control unit;

(2.8) calculate output voltage amplitude reference value V _Refmi: V _Refmi=V _Mrefoi+ K _Mpeqi+ K _Mi∫ e _QiDt; Wherein, V _MrefoiThe initial output voltage amplitude that provides for central control unit, 3.73 * 10 ^-3≤amplitude is regulated proportionality coefficient K _Mp≤4.32 * 10 ^-3, 1.12 * 10 ^-3≤amplitude is regulated integral coefficient K _Mi≤1.56 * 10 ^-3

(2.9) calculate the active voltage error e _Vdi: e _Vdi=V _Refmi-u _Di

(2.10) calculate active current reference value i _Di ^*: i _Di ^*=K _Vpde _Vdi+ K _Vid∫ e _VdiDt; Wherein, 0.72≤active voltage proportionality coefficient K _Vpd≤0.87,1789≤active voltage integral coefficient K _Vid≤1973;

(2.11) calculate the active current error e _Idi: e _Idi=i _Di ^*-i _Di

(2.12) calculate meritorious modulation voltage u _Rdi: u _Rdi=K _Ipde _Idi+ K _Iid∫ e _IdiDt; Wherein, 15.75≤active current proportionality coefficient K _Ipd≤19.06,1.92 * 10 ⁵≤active current integral coefficient K _Iid≤2.13 * 10 ⁵

(2.13) calculate the reactive voltage error e _Vqi: e _Vqi=0-u _Qi

(2.14) calculate reactive current reference value i _Qi ^*: i _Qi ^*=K _Vpqe _Vqi+ K _Viq∫ e _VqiDt; Wherein, reactive voltage proportionality coefficient K _Vpq=K _VpdReactive voltage integral coefficient K _Viq=K _Vid

(2.15) calculate the reactive current error e _Iqi: e _Iqi=i _Qi ^*-i _Qi

(2.16) calculate idle modulation voltage u _Rqi: u _Rqi=K _Ipqe _Iqi+ K _Iiq∫ e _IqiDt; Wherein, reactive current proportionality coefficient K _Ipq=K _IpdReactive current integral coefficient K _Iiq=K _Iid

(2.17) with the u under the synchronous rotating frame _RdiAnd u _RqiBe transformed to a phase modulation voltage u under the three phase static coordinate system _Rai, b phase modulation voltage u _Rbi, c phase modulation voltage u _Rci

(2.18) generate equivalent a phase space vector modulation signal u ' _Rai, b phase space vector modulation signal u ' _Rdi, c phase space vector modulation signal u ' _Rci:

$\left[\begin{array}{c}{u}_{\mathrm{rai}}^{\′}\\ u_{\mathrm{rbi}}^{\′}\\ u_{\mathrm{rci}}^{\′}\end{array}\right]=\left[\begin{array}{c}{u}_{\mathrm{rai}}\\ u_{\mathrm{rbi}}\\ u_{\mathrm{rci}}\end{array}\right]+u_{\mathrm{zi}}\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right];$

Wherein, zero-sequence component u _Zi=-[max (u _Rai, u _Rbi, u _Rci)+min (u _Rai, u _Rbi, u _Rci)]/2; Max and min are respectively maximizing and the operation function of minimizing;

(2.19) generate drive signal:

With u ' _Rai, u ' _Rbi, u ' _RciBe 3kHz with frequency respectively, amplitude is that 1 triangular carrier signal is compared, as u ' _RaiDuring greater than the triangular carrier sample, output first via drive signal is as u ' _RaiWhen being lower than the triangular carrier sample, export the second tunnel drive signal; As u ' _RbiDuring greater than the triangular carrier sample, output Third Road drive signal is as u ' _RbiWhen being lower than the triangular carrier sample, export the four tunnel drive signal; As u ' _RciDuring greater than the triangular carrier sample, export the five tunnel drive signal, as u ' _RciWhen being lower than the triangular carrier sample, export the six tunnel drive signal;

The first～the six tunnel drive signal that generates is delivered to two-way alternating current-direct current current transformer;

(2.20) calculate the DC bus-bar voltage error e _Vdci: e _Vdci=u _Dc ^*-u _DciWherein, u _Dc ^*=700V;

(2.21) the output battery current reference value i of calculating bidirectional, dc current transformer _Bati ^*:

i _Bati ^*=K _Vpdce _Vdci+ K _Vidc∫ e _VdciDt; Wherein, 0.067≤busbar voltage proportionality coefficient K _Vpdc≤0.081; 18.23≤busbar voltage integral coefficient K _Vidc≤22.06;

(2.22) the battery current error e of calculating bidirectional, dc current transformer _Ibati: e _Ibati=i _Bati ^*-i _Bati

(2.23) calculate bidirectional, dc current transformer modulation voltage u _Rdci:

u _Rdci=K _Ipbate _Ibati+ K _Iibat∫ e _IbatiDt; Wherein, 0.042≤battery current proportionality coefficient K _Ipbat≤0.051,5.28≤battery current integral coefficient K _Iibat≤6.39;

(2.24) generate bidirectional, dc current transformer drive signal:

With u _RdciWith frequency be 10kHz, amplitude is that 1 sawtooth signal is compared, and works as u _RdciDuring greater than the sawtooth signal instantaneous value, export the seven tunnel drive signal, work as u _RdciWhen being lower than the sawtooth signal instantaneous value, export the octuple drive signal;

With generate the 7th, the octuple drive signal delivers to the bidirectional, dc current transformer;

(2.25) change step (2.1);

(3) module that is incorporated into the power networks is carried out following operation:

(3.1) to the initial three-phase alternating voltage u of ac bus _{Sa, b, ci}, initial three-phase alternating current i _{Sa, b, ci}And initial DC bus-bar voltage u _Sdci, initial cell voltage u _SbatiWith the initial cells current i _SbatiCarry out filtering, obtain three-phase alternating voltage u _{A, b, ci}, three-phase alternating current i _{A, b, ci}, DC bus-bar voltage u _Dci, battery voltage u _Bati, output battery pack current i _Bati

(3.2) synchronizing signal of central control unit being sent is advanced horizontal lock, obtains phase angle theta _i

(3.3) utilize phase angle theta _iCarry out the coordinate system conversion, with three-phase alternating voltage u under the three phase static coordinate system _{A, b, ci}, three-phase alternating current i _{A, b, ci}Be transformed to and exchange active voltage u under the synchronous rotating frame _Di, exchange reactive voltage u _Qi, exchange active current i _Di, exchange reactive current i _Qi

Calculate the active power of output P of this subsystem _iAnd reactive power Q _i:

P _i＝u _dii _di+u _qii _qi，Q _i＝-u _dii _qi+u _qii _di，

With u _{A, b, ci}, i _{A, b, ci}, u _Dci, u _Bati, i _BatiDeliver to said central control unit through communication network, with P _iAnd Q _iDeliver to said central control unit through optical fiber;

(3.4) calculate active current reference value i _Di ^*: i _Di ^*=P _Refi/ u _Di

Wherein, P _RefiBe the active power reference value that provides by central control unit;

(3.5) calculate the active current error e _Idi: e _Idi=i _Di ^*-i _Di

(3.6) calculate meritorious modulation voltage u _Rdi: u _Rdi=K _Ipde _Idi+ K _Iid∫ e _IdiDt;

(3.7) calculate reactive current reference value i _Qi ^*: i _Qi ^*=-Q _Refi/ u _Di

Wherein, Q _RefiBe the reactive power reference qref that provides by central control unit;

(3.8) calculate the reactive current error e _Iqi: e _Iqi=i _Qi ^*-i _Qi

(3.9) calculate idle modulation voltage u _Rqi: u _Rqi=K _Ipqe _Iqi+ K _Iiq∫ e _IqiDt;

(3.10) identical with step (2.17)～step (2.24);

(3.11) change step (3.1);

B. said two-way alternating current-direct current current transformer adopts three-phase half-bridge voltage type current transformer or three phase full bridge voltage-type current transformer; When said two-way alternating current-direct current current transformer was three-phase half-bridge voltage type current transformer, the first～the six tunnel drive signal of said generation was delivered to the first～the six tunnel drive signal interface of two-way alternating current-direct current current transformer respectively; When said two-way alternating current-direct current current transformer is three phase full bridge voltage-type current transformer; Said first via drive signal is delivered to the first, the four tunnel drive signal interface of two-way alternating current-direct current current transformer respectively; The second tunnel drive signal is delivered to second, third road drive signal interface of two-way alternating current-direct current current transformer respectively; The Third Road drive signal deliver to respectively two-way alternating current-direct current current transformer the 5th, octuple drive signal interface; The four tunnel drive signal is delivered to the 6th, the seven tunnel drive signal interface of two-way alternating current-direct current current transformer respectively; The five tunnel drive signal is delivered to the 9th, the ten two tunnel drive signal interfaces of two-way alternating current-direct current current transformer respectively, and the six tunnel drive signal is delivered to the tenth, the ten one tunnel drive signal interfaces of two-way alternating current-direct current current transformer respectively;

C. said bidirectional, dc current transformer adopts two-way Buck/Boost current transformer;

D. said battery pack adopts flow battery or ferric phosphate lithium cell.

Described parallel connection discharges and recharges power conversion system, it is characterized in that, in the controller islet operation module of said each subsystem:

(1). said active voltage proportionality coefficient K _VpdWith active voltage integral coefficient K _VidDeterministic process is:

(1.1) with K _VpdInitial value is taken as 0.72, K _VidInitial value is taken as 0;

(1.2) debug K earlier _Vpd, check three-phase alternating voltage u this moment _{A, b, c}Whether waveform vibrates, and is then to increase K _VpdEliminate until oscillating waveform, turn over journey (1.3); Otherwise directly turn over journey (1.3);

(1.3) fixing K _VpdValue is with K _VidBe taken as 1789, debugging K _Vid, check three-phase alternating voltage u this moment _{A, b, c}Whether waveform fluctuates, and is then to strengthen K _VidEliminate until fluctuation;

(2). said active current proportionality coefficient K _IpdWith active current integral coefficient K _IidDeterministic process is:

(2.1) with K _IpdInitial value is taken as 17.32, K _IidInitial value is taken as 0;

(2.2) debug K earlier _Ipd, check three-phase alternating current i this moment _{A, b, c}Whether waveform vibrates, and is then to increase K _IpdEliminate until oscillating waveform, turn over journey (2.3); Otherwise directly turn over journey (2.3);

(2.3) fixing K _IpdValue is with K _IidBe taken as 2.02 * 10 ⁵, debugging K _Iid, check three-phase alternating current i this moment _{A, b, c}Whether waveform fluctuates, and is then to strengthen K _IidEliminate until fluctuation;

(3). said busbar voltage proportionality coefficient K _VpdcWith busbar voltage integral coefficient K _VidcDeterministic process is:

(3.1) with K _VpdcInitial value is taken as 0.067, K _VidcInitial value is taken as 0;

(3.2) debug K earlier _Vpdc, check DC bus-bar voltage u this moment _DcWhether waveform vibrates, and is then to increase K _VpdcEliminate until oscillating waveform, turn over journey (3.3); Otherwise directly turn over journey (3.3);

(3.3) fixing K _VpdcValue is with K _VidcBe taken as 18.23, debugging K _Vidc, check DC bus-bar voltage u this moment _DcWhether waveform fluctuates, and is then to strengthen K _VidcEliminate until fluctuation;

(4). said battery current proportionality coefficient K _IpbatWith battery current integral coefficient K _IibatDeterministic process is:

(4.1) with K _IpbatInitial value is taken as 0.042, K _IibatInitial value is taken as 0;

(4.2) debug K earlier _Ipbat, check i Battery pack current i this moment _BatiWhether waveform vibrates, and is then to increase K _IpbatEliminate until oscillating waveform, turn over journey (4.3); Otherwise directly turn over journey (4.3);

(4.3) fixing K _IpbatValue is with K _IibatBe taken as 5.28, debugging K _Iibat, check i Battery pack current i this moment _BatiWhether waveform fluctuates, and is then to strengthen K _IibatEliminate until fluctuation;

(5). said frequency adjustment proportionality coefficient K _FpWith frequency adjustment integral coefficient K _FiDeterministic process is:

(5.1) with K _FpInitial value is taken as 3.73 * 10 ^-3, K _FiInitial value is taken as 0;

(5.2) debug K earlier _Fp, check the time that each subsystem output this moment active current reaches unanimity, if the time is greater than 2s then increase K _Fp, turn over journey (5.3); Otherwise directly turn over journey (5.3);

(5.3) fixing K _FpValue is with K _FiBe taken as 1.12 * 10 ^-3, debugging K _Fi, check the equal stream error of each subsystem output active current this moment, increase K _FiCan reduce the equal stream error of active current;

(6). said amplitude is regulated proportionality coefficient K _MpRegulate integral coefficient K with amplitude _MiDeterministic process is:

(6.1) with K _MpInitial value is taken as 3.73 * 10 ^-3, K _MiInitial value is taken as 0;

(6.2) debug K earlier _Mp, check the time that each subsystem output this moment reactive current reaches unanimity, if the time is greater than 2s then increase K _Mp, turn over journey (6.3); Otherwise directly turn over journey (6.3);

(6.3) fixing K _MpValue is with K _MiBe taken as 1.12 * 10 ^-3, debugging K _Mi, check the equal stream error of each subsystem output reactive current this moment, increase K _MiCan reduce the equal stream error of reactive current.

Among the present invention, 120 ° of A in the three phase static coordinate system, B, C three-phase mutual deviation, the present invention mainly handles three-phase alternating voltage and three-phase alternating current with it; Synchronous rotating frame is made up of the D axle and the Q axle of 90 ° of mutual deviations, and the two rotates with angular speed with respect to the three phase static coordinate system together, and the present invention mainly handles each controlled quentity controlled variable with it.

The present invention adopts heterarchical architecture, adopts the high speed communication network to carry out exchanges data between host computer, central control unit and each subsystem controller, and wherein, the host computer of top layer is responsible for man-machine interaction; The middle level central control unit obtains instruction from host computer, receives meritorious, the reactive power information of each subsystem simultaneously and carries out comprehensive computing, and send synchronizing signal and control command to each subsystem; The controller of each subsystem is accomplished the two-way scheduling of current transformer energy stream and is discharged and recharged control strategy.The present invention has that power system capacity is big, the message transmission reliability high, fireballing advantage; Through adopting two-way alternating current-direct current current transformer, bidirectional, dc current transformer to adapt to the charge-discharge characteristic of large-capacity battery pack; Hierarchical control then realized easily between each subsystem synchronously, thereby realize that multiple subsystem is incorporated into the power networks, the seamless switching between multiple subsystem parallel connection islet operation and this two kinds of operating modes.Be applicable to the energy-storage system that adopts large-capacity battery pack.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the invention;

Fig. 2 is a central control unit pattern determining step sketch map;

Fig. 3 is that the central control unit isolated island is to being incorporated into the power networks the switch step sketch map;

Fig. 4 is incorporated into the power networks to isolated island switch step sketch map for central control unit;

Fig. 5 is the islet operation module diagram of subsystem controller;

Fig. 6 is the module diagram that is incorporated into the power networks of subsystem controller;

Embodiment

As shown in Figure 1, the embodiment of the invention comprises host computer, central control unit and 10 sub-systems, and each subsystem structure is identical, includes isolating transformer, two-way alternating current-direct current current transformer, bidirectional, dc current transformer, battery pack and controller; The isolating transformer of each subsystem links to each other with ac bus, and ac bus is connected to electrical network or is connected to local load through local K switch L through the K switch g that is incorporated into the power networks; Said host computer is connected with central control unit through communication cable; Central control unit through communication network and optical fiber respectively with the controller communication of each subsystem, each subsystem controller is controlled the work of corresponding subsystem pair DC convertors and AC/DC convertor.

In each subsystem, two-way alternating current-direct current current transformer can connect isolating transformer through K switch i, i=1～n, and in the present embodiment, n=4.

Host computer passes through the RS485 communications protocol to central control unit transmit operation instruction, pattern input variable j, active power value P _Ref=1MW and reactive power value Q _Ref=120kVar, said operational order comprises startup and shutdown; The value of said pattern input variable j is 1 or 2; When receiving the electric network fault signal of central control unit transmission through optical fiber, make pattern input variable j=1;

Central control unit carries out following operation:

(1) as shown in Figure 2, the pattern determining step comprises sub-steps:

(1.1) put control model variable m=0, whether the decision operation instruction is shutdown, is then to close central control unit; Otherwise periodically whether judgment model input variable j equals control model variable m, is rotor step (1.2) then, otherwise rotor step (1.3);

(1.2) if m=1 changes step (3); Otherwise change step (2);

(1.3) putting m=j, judge whether m=1, is then to change step (5); Otherwise change step (4);

(2) step that is incorporated into the power networks comprises sub-steps:

(2.1) line voltage is detected with locking obtain electrical network amplitude V mutually _g, synchronizing signal θ and mains frequency f _g

(2.2) electric network state is judged:

Judge whether 264.4V≤V _g≤342.1V and 49.5Hz≤f _g≤50.5Hz is that then electrical network is a normal condition, and the closure switch that is incorporated into the power networks sends control model variable m=2, rotor step (2.3) through optical fiber to each subsystem; Otherwise electrical network is a malfunction, sends the electric network fault signal to host computer, changes step (1);

(2.3) the active power value P of wait host computer _RefWith reactive power value Q _Ref, calculate the active power reference value P of each subsystem _RefiWith reactive power reference qref Q _Refi:

$P_{\mathrm{refi}}=\frac{P_{\mathrm{ref}}\·k_i\·{\mathrm{SOC}}_i}{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{k}_x\·{\mathrm{SOC}}_x},$ $Q_{\mathrm{refi}}=\frac{Q_{\mathrm{ref}}}{N};$

Wherein, SOC _iBe i subsystem battery pack state-of-charge, k _iBe SOC _iThe weights coefficient, k _i, k _xSpan is 0～1,

(2.4) send synchronizing signal and corresponding active power reference value P to each subsystem controller _RefiWith reactive power reference qref Q _Refi, rotor step (2.1);

(3) islet operation step comprises sub-steps:

(3.1) break off the switch that is incorporated into the power networks, send control model variable m=1 to each subsystem through optical fiber; Utilize counter to obtain the initial synchronisation signal

X is the current time count value, and X=mod (10 ⁶/ 2 ^T), mod representes the value in the bracket is rounded, and T is 0～7 integer, counter per 20 * 2 ^TNs adds 1;

(3.2) the active power P that exports according to each subsystem _i, reactive power Q _iWith battery pack state-of-charge SOC _iCalculate the active power reference value P of each subsystem _RefiWith reactive power reference qref Q _Refi:

$P_{\mathrm{refi}}=\frac{k_i\·{\mathrm{SOC}}_i\·\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{P}_x}{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{k}_x\·{\mathrm{SOC}}_x},$ $Q_{\mathrm{refi}}=\frac{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{Q}_x}{N};$

(3.3) send initial synchronisation signal, corresponding active power reference value P to each subsystem controller _Refi, reactive power reference qref Q _RefiWith initial output voltage amplitude V _Mrefo=311V, rotor step (3.1);

(4) as shown in Figure 3, isolated island comprises sub-steps to the switch step that is incorporated into the power networks:

(4.1) line voltage is detected with locking obtain electrical network amplitude V mutually _g, synchronizing signal θ and mains frequency f _g

(4.2) electric network state is judged:

Judge whether 264.4V≤V _g≤342.1V and 49.5Hz≤f _g≤50.5Hz is that then electrical network is a normal condition, rotor step (4.3); Otherwise electrical network is a malfunction, sends the electric network fault signal to host computer, changes step (1);

(4.3) put the initial synchronisation signal

Put initial output voltage amplitude V _Mrefo=V _g

(4.4) the closure switch that is incorporated into the power networks, and send control model variable m=2 to each subsystem through optical fiber;

(4.5) send synchronizing signal θ and corresponding active power reference value P to each subsystem controller _Refi=0 with reactive power reference qref Q _Refi=0;

(5) as shown in Figure 4, be incorporated into the power networks to the isolated island switch step, comprise sub-steps:

(5.1) detect the active power P that parallel connection discharges and recharges power conversion system output _gAnd reactive power Q _g

(5.2) break off the switch that is incorporated into the power networks, and send control model variable m=1, initial output voltage amplitude V to each subsystem through optical fiber _Mrefo=311V, initial synchronisation signal

The active power reference value

And reactive power reference qref

Each subsystem all has the bidirectional, dc current transformer; In each subsystem; Isolating transformer connects two-way alternating current-direct current current transformer through switch, and two-way alternating current-direct current current transformer connects the bidirectional, dc current transformer through dc bus, and the bidirectional, dc current transformer links to each other with battery pack; Controller generates the first～the six tunnel drive signal and delivers to two-way alternating current-direct current current transformer, and controller generates the 7th, the octuple drive signal is delivered to the bidirectional, dc current transformer;

The controller of i sub-systems comprises pattern judge module, islet operation module, module is incorporated into the power networks; I=1～N;

(1) the pattern judge module carries out following operation:

(1.1) put mode of operation variable n=0, put output voltage frequency f _i=50Hz;

(1.2) periodically judge whether control model variable m equals work at present pattern variable n, and being then changes step (1.4); Otherwise change step (1.3);

(1.3) value of control model variable m is composed to mode of operation variable n;

(1.4) mode of operation variable n is judged:

N=1 changes (2) islet operation module;

N=2 changes (3) module that is incorporated into the power networks;

(2) as shown in Figure 5, the islet operation module is carried out following operation:

(2.1) to the initial three-phase alternating voltage u of ac bus _{Sa, b, ci}, initial three-phase alternating current i _{Sa, b, ci}And initial DC bus-bar voltage u _Sdci, initial cell voltage u _SbatiWith the initial cells current i _SbatiCarry out filtering, obtain three-phase alternating voltage u _{A, b, ci}, three-phase alternating current i _{A, b, ci}, DC bus-bar voltage u _Dci, battery voltage u _Bati, output battery pack current i _Bati

(2.2) synchronizing signal of central control unit being sent is advanced horizontal lock, obtains initial phase angle

(2.3) calculate phase angle

(2.4) utilize phase angle

Carry out the coordinate system conversion, with three-phase alternating voltage u under the three phase static coordinate system _{A, b, ci}, three-phase alternating current i _{A, b, ci}Be transformed to and exchange active voltage u under the synchronous rotating frame _Di, exchange reactive voltage u _Qi, exchange active current i _Di, exchange reactive current i _Qi

Calculate the active power of output P of this subsystem _iAnd reactive power Q _i:

P _i＝u _dii _di+u _qii _qi，Q _i＝-u _dii _qi+u _qii _di，

With u _{A, b, ci}, i _{A, b, ci}, u _Dci, u _Bati, i _BatiDeliver to said central control unit through communication network, with P _iAnd Q _iDeliver to said central control unit through optical fiber;

(2.5) calculate the active power error e _Pi: e _Pi=P _Refi-P _iWherein, P _RefiThe active power reference value of the i sub-systems that provides for central control unit;

(2.6) calculate output voltage frequency f _i: f _i=50+K _Fpe _Pi+ K _fI ∫ e _PiDt; Wherein, K _Fp=3.8 * 10 ^-3, K _Fi=1.5 * 10 ^-3

(2.7) calculate the reactive power error e _Qi: e _Qi=Q _Refi-Q _iWherein, Q _RefiThe reactive power reference qref of the i sub-systems that provides for central control unit;

(2.8) calculate output voltage amplitude reference value V _Refmi: V _Refmi=V _Mrefoi+ K _Mpeqi+ K _Mi∫ e _QiDt; Wherein, V _MrefoiBe the initial output voltage amplitude that central control unit provides, K _Mp=3.8 * 10 ^-3, K _Mi=1.5 * 10 ^-3

(2.9) calculate the active voltage error e _Vdi: e _Vdi=V _Refmi-u _Di

(2.10) calculate active current reference value i _Di ^*: i _Di ^*=K _Vpde _Vdi+ K _Vid∫ e _VdiDt; Wherein, K _Vpd=0.8, K _Vid=1865;

(2.11) calculate the active current error e _Idi: e _Idi=i _Di ^*-i _Di

(2.12) calculate meritorious modulation voltage u _Rdi: u _Rdi=K _Ipde _Idi+ K _Iid∫ e _IdiDt; Wherein, K _Ipd=16.72, K _Iid=2.03 * 10 ⁵

(2.13) calculate the reactive voltage error e _Vqi: e _Vqi=0-u _Qi

(2.14) calculate reactive current reference value i _Qi ^*: i _Qi ^*=K _Vpqe _Vqi+ K _Viq∫ e _VqiDt; Wherein, K _Vpq=K _Vpd, K _Viq=K _Vid

(2.15) calculate the reactive current error e _Iqi: e _Iqi=i _Qi ^*-i _Qi

(2.16) calculate idle modulation voltage u _Rqi: u _Rqi=K _Ipqe _Iqi+ K _Iiq∫ e _IqiDt; Wherein, K _Ipq=K _Ipd, K _Iiq=K _Iid

(2.17) with the u under the synchronous rotating frame _RdiAnd u _RqiBe transformed to a phase modulation voltage u under the three phase static coordinate system _Rai, b phase modulation voltage u _Rbi, c phase modulation voltage u _Rci

(2.18) generate equivalent a phase space vector modulation signal u ' _Rai, b phase space vector modulation signal u ' _Rbi, c phase space vector modulation signal u ' _Rci:

$\left[\begin{array}{c}{u}_{\mathrm{rai}}^{\′}\\ u_{\mathrm{rbi}}^{\′}\\ u_{\mathrm{rci}}^{\′}\end{array}\right]=\left[\begin{array}{c}{u}_{\mathrm{rai}}\\ u_{\mathrm{rbi}}\\ u_{\mathrm{rci}}\end{array}\right]+u_{\mathrm{zi}}\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right];$

Wherein, zero-sequence component u _Zi=-[max (u _Rai, u _Rbi, u _Rci)+min (u _Rai, u _Rbi, u _Rci)]/2; Max and min are respectively maximizing and the operation function of minimizing;

(2.19) generate drive signal:

With u ' _Rai, u ' _Rbi, u ' _RciBe 3kHz with frequency respectively, amplitude is that 1 triangular carrier signal is compared, as u ' _RaiDuring greater than the triangular carrier sample, output first via drive signal is as u ' _RaiWhen being lower than the triangular carrier sample, export the second tunnel drive signal; As u ' _RbiDuring greater than the triangular carrier sample, output Third Road drive signal is as u ' _RbiWhen being lower than the triangular carrier sample, export the four tunnel drive signal; As u ' _RciDuring greater than the triangular carrier sample, export the five tunnel drive signal, as u ' _RciWhen being lower than the triangular carrier sample, export the six tunnel drive signal;

The first～the six tunnel drive signal that generates is delivered to two-way alternating current-direct current current transformer;

(2.20) calculate the DC bus-bar voltage error e _Vdci: e _Vdci=u _Dc ^*-u _DciWherein, u _Dc ^*=700V;

(2.21) the output battery current reference value i of calculating bidirectional, dc current transformer _Bati ^*:

i _Bati ^*=K _Vpdce _Vdci+ K _Vidc∫ e _VdciDt; Wherein, K _Vpdc=0.071; K _Vidc=19.23;

(2.22) the battery current error e of calculating bidirectional, dc current transformer _Ibati: e _Ibati=i _Bati ^*-i _Bati

(2.23) calculate bidirectional, dc current transformer modulation voltage u _Rdci:

u _Rdci=K _Ipbate _Ibati+ K _Iibat∫ e _IbatiDt; Wherein, K _Ipbat=0.048, K _Iibat=5.61;

(2.24) generate bidirectional, dc current transformer drive signal:

With u _RdciWith frequency be 10kHz, amplitude is that 1 sawtooth signal is compared, and works as u _RdciDuring greater than the sawtooth signal instantaneous value, export the seven tunnel drive signal, work as u _RdciWhen being lower than the sawtooth signal instantaneous value, export the octuple drive signal;

With generate the 7th, the octuple drive signal delivers to the bidirectional, dc current transformer;

(2.25) change step (2.1);

(3) as shown in Figure 6, the module that is incorporated into the power networks is carried out following operation:

(3.1) to the initial three-phase alternating voltage u of ac bus _{Sa, b, ci}, initial three-phase alternating current i _{Sa, b, ci}And initial DC bus-bar voltage u _Sdci, initial cell voltage u _SbatiWith the initial cells current i _SbatiCarry out filtering, obtain three-phase alternating voltage u _{A, b, ci}, three-phase alternating current i _{A, b, ci}, DC bus-bar voltage u _Dci, battery voltage u _Bati, output battery pack current i _Bati

(3.2) synchronizing signal of central control unit being sent is advanced horizontal lock, obtains phase angle theta _i

(3.3) utilize phase angle theta _iCarry out the coordinate system conversion, with three-phase alternating voltage u under the three phase static coordinate system _{A, b, ci}, three-phase alternating current i _{A, b, ci}Be transformed to and exchange active voltage u under the synchronous rotating frame _Di, exchange reactive voltage u _Qi, exchange active current i _Di, exchange reactive current i _Qi

Calculate the active power of output P of this subsystem _iAnd reactive power Q _i:

P _i＝u _dii _di+u _qii _qi，Q _i＝-u _dii _qi?+u _qii _di，

With u _{A, b, ci}, i _{A, b, ci}, u _Dci, u _Bati, i _BatiDeliver to said central control unit through communication network, with P _iAnd Q _iDeliver to said central control unit through optical fiber;

(3.4) calculate active current reference value i _Di ^*: i _Di ^*=P _Refi/ u _Di

Wherein, P _RefiBe the active power reference value that provides by central control unit;

(3.5) calculate the active current error e _Idi: e _Idi=i _Di ^*-i _Di

(3.6) calculate meritorious modulation voltage u _Rdi: u _Rdi=K _Ipde _Idi+ K _Iid∫ e _IdiDt;

(3.7) calculate reactive current reference value i _Di ^*: i _Qi ^*=-Q _Refi/ u _Di

Wherein, Q _RefiBe the reactive power reference qref that provides by central control unit;

(3.8) calculate the reactive current error e _Iqi: e _Iqi=i _Qi ^*-i _Qi

(3.9) calculate idle modulation voltage u _Rqi: u _Rqi=K _Ipqe _Iqi+ K _Iiq∫ e _IqiDt;

(3.10) identical with step (2.17)～step (2.24);

(3.11) change step (3.1).

Claims (2)

1. a parallel connection discharges and recharges power conversion system, comprises host computer, central control unit and N sub-systems, and each subsystem structure is identical, includes isolating transformer, two-way alternating current-direct current current transformer, bidirectional, dc current transformer, battery pack and controller; The isolating transformer of each subsystem links to each other with ac bus, and ac bus is connected to electrical network or is connected to local load through local switch through the switch that is incorporated into the power networks; Said host computer is connected with central control unit through communication cable, central control unit pass through communication network and optical fiber respectively with the controller communication of each subsystem, N=1～10 is characterized in that:

(1) said host computer, through the RS485 communications protocol to central control unit transmit operation instruction, pattern input variable j, active power value P _RefWith reactive power value Q _Ref, said operational order comprises startup and shutdown; The value of said pattern input variable j is 1 or 2; When receiving the electric network fault signal of central control unit transmission through optical fiber, make pattern input variable j=1;

(2) said central control unit, carry out following operation:

(1) pattern is judged:

(1.1) put control model variable m=0, whether the decision operation instruction is shutdown, is then to close central control unit; Otherwise periodically whether judgment model input variable j equals control model variable m, is rotor step (1.2) then, otherwise rotor step (1.3);

(1.2) if m=1 changes step (3); Otherwise change step (2);

(1.3) putting m=j, judge whether m=1, is then to change step (5); Otherwise change step (4);

(2) step that is incorporated into the power networks comprises sub-steps:

(2.1) line voltage is detected with locking obtain electrical network amplitude V mutually _g, synchronizing signal θ and mains frequency f _g

(2.2) electric network state is judged:

Judge whether 264.4V≤V _g≤342.1V and 49.5Hz≤f _g≤50.5Hz is that then electrical network is a normal condition, and the closure switch that is incorporated into the power networks sends control model variable m=2, rotor step (2.3) through optical fiber to each subsystem; Otherwise electrical network is a malfunction, sends the electric network fault signal to host computer, changes step (1);

(2.3) the active power value P of wait host computer _RefWith reactive power value Q _Ref, calculate the active power reference value P of each subsystem _RefiWith reactive power reference qref Q _Refi:

$P_{\mathrm{refi}}=\frac{P_{\mathrm{ref}}\·k_i\·{\mathrm{SOC}}_i}{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{k}_x\·{\mathrm{SOC}}_x},$ $Q_{\mathrm{refi}}=\frac{Q_{\mathrm{ref}}}{N};$

Wherein, SOC _iBe i subsystem battery pack state-of-charge, k _iBe SOC _iThe weights coefficient, k _i, k _xSpan is 0～1,

(2.4) send synchronizing signal and corresponding active power reference value P to each subsystem controller _RefiWith reactive power reference qref Q _Refi, rotor step (2.1);

(3) islet operation step comprises sub-steps:

(3.1) break off the switch that is incorporated into the power networks, send control model variable m=1 to each subsystem through optical fiber; Utilize counter to obtain the initial synchronisation signal

X is the current time count value, and X=mod (10 ⁶/ 2 ^T), mod representes the value in the bracket is rounded, and T is 0～7 integer, counter per 20 * 2 ^TNs adds 1;

(3.2) the active power P that exports according to each subsystem _i, reactive power Q _iWith battery pack state-of-charge SOC _iCalculate the active power reference value P of each subsystem _RefiWith reactive power reference qref Q _Refi:

$P_{\mathrm{refi}}=\frac{k_i\·{\mathrm{SOC}}_i\·\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{P}_x}{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{k}_x\·{\mathrm{SOC}}_x},$ $Q_{\mathrm{refi}}=\frac{\underset{x=1}{\overset{N}{\mathrm{\Σ}}}{Q}_x}{N};$

(3.3) send initial synchronisation signal, corresponding active power reference value P to each subsystem controller _Refi, reactive power reference qref Q _RefiWith initial output voltage amplitude V _Mrefo=311V, rotor step (3.1);

(4) isolated island comprises sub-steps to the switch step that is incorporated into the power networks:

(4.1) line voltage is detected with locking obtain electrical network amplitude V mutually _g, synchronizing signal θ and mains frequency f _g

(4.2) electric network state is judged:

Judge whether 264.4V≤V _g≤342.1V and 49.5Hz≤f _g≤50.5Hz is that then electrical network is a normal condition, rotor step (4.3); Otherwise electrical network is a malfunction, sends the electric network fault signal to host computer, changes step (1);

(4.3) put the initial synchronisation signal

Put initial output voltage amplitude V _Mrefo=V _g

(4.4) the closure switch that is incorporated into the power networks, and send control model variable m=2 to each subsystem through optical fiber;

(4.5) send synchronizing signal θ and corresponding active power reference value P to each subsystem controller _Refi=0 with reactive power reference qref Q _Refi=0;

(5) be incorporated into the power networks to the isolated island switch step, comprise sub-steps:

(5.1) detect the active power P that parallel connection discharges and recharges power conversion system output _gAnd reactive power Q _g

(5.2) break off the switch that is incorporated into the power networks, and send control model variable m=1, initial output voltage amplitude V to each subsystem through optical fiber _Mrefo=311V, initial synchronisation signal

The active power reference value

And reactive power reference qref

(3) said each subsystem all has the bidirectional, dc current transformer; In each subsystem; Isolating transformer connects two-way alternating current-direct current current transformer through switch, and two-way alternating current-direct current current transformer connects the bidirectional, dc current transformer through dc bus, and the bidirectional, dc current transformer links to each other with battery pack; Controller generates the first～the six tunnel drive signal and delivers to two-way alternating current-direct current current transformer, and controller generates the 7th, the octuple drive signal is delivered to the bidirectional, dc current transformer;

A. the controller of i sub-systems comprises pattern judge module, islet operation module, module is incorporated into the power networks; I=1～N;

(1) the pattern judge module carries out following operation:

(1.1) put mode of operation variable n=0, put output voltage frequency f _i=50Hz;

(1.2) periodically judge whether control model variable m equals work at present pattern variable n, and being then changes step (1.4); Otherwise change step (1.3);

(1.3) value of control model variable m is composed to mode of operation variable n;

(1.4) mode of operation variable n is judged:

N=1 changes (2) islet operation module;

N=2 changes (3) module that is incorporated into the power networks;

(2) the islet operation module is carried out following operation:

(2.1) to the initial three-phase alternating voltage u of ac bus _{Sa, b, ci}, initial three-phase alternating current i _{Sa, b, ci}And initial DC bus-bar voltage u _Sdci, initial cell voltage u _SbatiWith the initial cells current i _SbatiCarry out filtering, obtain three-phase alternating voltage u _{A, b, ci}, three-phase alternating current i _{A, b, ci}, DC bus-bar voltage u _Dci, battery voltage u _Bati, output battery pack current i _Bati

(2.2) synchronizing signal of central control unit being sent is advanced horizontal lock, obtains initial phase angle

(2.3) calculate phase angle

(2.4) utilize phase angle

Carry out the coordinate system conversion, with three-phase alternating voltage u under the three phase static coordinate system _{A, b, ci}, three-phase alternating current i _{A, b, ci}Be transformed to and exchange active voltage u under the synchronous rotating frame _Di, exchange reactive voltage u _Qi, exchange active current i _Di, exchange reactive current i _Qi

Calculate the active power of output P of this subsystem _iAnd reactive power Q _i:

P _i＝u _dii _di+u _qii _qi，Q _i＝-u _dii _qi+u _qii _di，

With u _{A, b, ci}, i _{A, b, ci}, u _Dci, u _Bati, i _BatiDeliver to said central control unit through communication network, with P _iAnd Q _iDeliver to said central control unit through optical fiber;

(2.5) calculate the active power error e _Pi: e _Pi=P _Refi-P _iWherein, P _RefiThe active power reference value of the i sub-systems that provides for central control unit;

(2.6) calculate output voltage frequency f _i: f _i=50+K _Fpe _Pi+ K _Fi∫ e _PiDt; Wherein, 3.73 * 10 ^-3≤frequency adjustment proportionality coefficient K _Fp≤4.32 * 10 ^-3, 1.12 * 10 ^-3≤frequency adjustment integral coefficient K _Fi≤1.56 * 10 ^-3

(2.7) calculate the reactive power error e _Qi: e _Qi=Q _Refi-Q _iWherein, Q _RefiThe reactive power reference qref of the i sub-systems that provides for central control unit;

(2.8) calculate output voltage amplitude reference value V _Refmi: V _Refmi=V _Mrefoi+ K _Mpeqi+ K _Mi∫ e _QiDt; Wherein, V _MrefoiThe initial output voltage amplitude that provides for central control unit, 3.73 * 10 ^-3≤amplitude is regulated proportionality coefficient K _Mp≤4.32 * 10 ^-3, 1.12 * 10 ^-3≤amplitude is regulated integral coefficient K _Mi≤1.56 * 10 ^-3

(2.9) calculate the active voltage error e _Vdi: e _Vdi=V _Refmi-u _Di

(2.10) calculate active current reference value i _Di ^*: i _Di ^*=K _Vpde _Vdi+ K _Vid∫ e _VdiDt; Wherein, 0.72≤active voltage proportionality coefficient K _Vpd≤0.87,1789≤active voltage integral coefficient K _Vid≤1973;

(2.11) calculate the active current error e _Idi: e _Idi=i _Di ^*-i _Di

(2.12) calculate meritorious modulation voltage u _Rdi: u _Rdi=K _Ipde _Idi+ K _Iid∫ e _IdiDt; Wherein, 15.75≤active current proportionality coefficient K _Ipd≤19.06,1.92 * 10 ⁵≤active current integral coefficient K _Iid≤2.13 * 10 ⁵

(2.13) calculate the reactive voltage error e _Vqi: e _Vqi=0-u _Qi

(2.14) calculate reactive current reference value i _Qi ^*: i _Qi ^*=K _Vpqe _Vqi+ K _Viq∫ e _VqiDt; Wherein, reactive voltage proportionality coefficient K _Vpq=K _VpdReactive voltage integral coefficient K _Viq=K _Vid

(2.15) calculate the reactive current error e _Iqi: e _Iqi=i _Qi ^*-i _Qi

(2.16) calculate idle modulation voltage u _Rqi: u _Rqi=K _Ipqe _Iqi+ K _Iiq∫ e _IqiDt; Wherein, reactive current proportionality coefficient K _Ipq=K _IpdReactive current integral coefficient K _Iiq=K _Iid

(2.17) with the u under the synchronous rotating frame _RdiAnd u _RqiBe transformed to a phase modulation voltage u under the three phase static coordinate system _Rai, b phase modulation voltage u _Rbi, c phase modulation voltage u _Rci

(2.18) generate equivalent a phase space vector modulation signal u ' _Rai, b phase space vector modulation signal u ' _Rbi, c phase space vector modulation signal u ' _Rci:

$\left[\begin{array}{c}{u}_{\mathrm{rai}}^{\′}\\ u_{\mathrm{rbi}}^{\′}\\ u_{\mathrm{rci}}^{\′}\end{array}\right]=\left[\begin{array}{c}{u}_{\mathrm{rai}}\\ u_{\mathrm{rbi}}\\ u_{\mathrm{rci}}\end{array}\right]+u_{\mathrm{zi}}\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right];$

Wherein, zero-sequence component u _Zi=-[max (u _Rai, u _Rbi, u _Rci)+min (u _Rai, u _Rbi, u _Rci)]/2; Max and min are respectively maximizing and the operation function of minimizing;

(2.19) generate drive signal:

With u ' _Rai, u ' _Rbi, u ' _RciBe 3kHz with frequency respectively, amplitude is that 1 triangular carrier signal is compared, as u ' _RaiDuring greater than the triangular carrier sample, output first via drive signal is as u ' _RaiWhen being lower than the triangular carrier sample, export the second tunnel drive signal; As u ' _RbiDuring greater than the triangular carrier sample, output Third Road drive signal is as u ' _RbiWhen being lower than the triangular carrier sample, export the four tunnel drive signal; As u ' _RciDuring greater than the triangular carrier sample, export the five tunnel drive signal, as u ' _RciWhen being lower than the triangular carrier sample, export the six tunnel drive signal;

The first～the six tunnel drive signal that generates is delivered to two-way alternating current-direct current current transformer;

(2.20) calculate the DC bus-bar voltage error e _Vdci: e _Vdci=u _Dc ^*-u _DciWherein, u _Dc ^*=700V;

(2.21) the output battery current reference value i of calculating bidirectional, dc current transformer _Bati ^*:

i _Bati ^*=K _Vpdce _Vdci+ K _Vidc∫ e _VdciDt; Wherein, 0.067≤busbar voltage proportionality coefficient K _Vpdc≤0.081; 18.23≤busbar voltage integral coefficient K _Vidc≤22.06;

(2.22) the battery current error e of calculating bidirectional, dc current transformer _Ibati: e _Ibati=i _Bati ^*-i _Bati

(2.23) calculate bidirectional, dc current transformer modulation voltage u _Rdci:

u _Rdci=K _Ipbate _Ibati+ K _Iibat∫ e _IbatiDt; Wherein, 0.042≤battery current proportionality coefficient K _Ipbat≤0.051,5.28≤battery current integral coefficient K _Iibat≤6.39;

(2.24) generate bidirectional, dc current transformer drive signal:

With u _RdciWith frequency be 10kHz, amplitude is that 1 sawtooth signal is compared, and works as u _RdciDuring greater than the sawtooth signal instantaneous value, export the seven tunnel drive signal, work as u _RdciWhen being lower than the sawtooth signal instantaneous value, export the octuple drive signal;

With generate the 7th, the octuple drive signal delivers to the bidirectional, dc current transformer;

(2.25) change step (2.1);

(3) module that is incorporated into the power networks is carried out following operation:

(3.1) to the initial three-phase alternating voltage u of ac bus _{Sa, b, ci}, initial three-phase alternating current i _{Sa, b, ci}And initial DC bus-bar voltage u _Sdci, initial cell voltage u _SbatiWith the initial cells current i _SbatiCarry out filtering, obtain three-phase alternating voltage u _{A, b, ci}, three-phase alternating current i _{A, b, ci}, DC bus-bar voltage u _Dci, battery voltage u _Bati, output battery pack current i _Bati

(3.2) synchronizing signal of central control unit being sent is advanced horizontal lock, obtains phase angle theta _i

(3.3) utilize phase angle theta _iCarry out the coordinate system conversion, with three-phase alternating voltage u under the three phase static coordinate system _{A, b, ci}, three-phase alternating current i _{A, b, ci}Be transformed to and exchange active voltage u under the synchronous rotating frame _Di, exchange reactive voltage u _Qi, exchange active current i _Di, exchange reactive current i _Qi

Calculate the active power of output P of this subsystem _iAnd reactive power Q _i:

P _i＝u _dii _di+u _qii _qi，Q _i＝-u _dii _qi+u _qii _di，

With u _{A, b, ci}, i _{A, b, ci}, u _Dci, u _Bati, i _BatiDeliver to said central control unit through communication network, with P _iAnd Q _iDeliver to said central control unit through optical fiber;

(3.4) calculate active current reference value i _Di ^*: i _Di ^*=P _Refi/ u _Di

Wherein, P _RefiBe the active power reference value that provides by central control unit;

(3.5) calculate the active current error e _Idi: e _Idi=i _Di ^*-i _Di

(3.6) calculate meritorious modulation voltage u _Rdi: u _Rdi=K _Ipde _Idi+ K _Iid∫ e _IdiDt;

(3.7) calculate reactive current reference value i _Qi ^*: i _Qi ^*=-Q _Refi/ u _Di

Wherein, Q _RefiBe the reactive power reference qref that provides by central control unit;

(3.8) calculate the reactive current error e _Iqi: e _Iqi=i _Qi ^*-i _Qi

(3.9) calculate idle modulation voltage u _Rqi: u _Rqi=K _Ipqe _Iqi+ K _Iiq∫ e _IqiDt;

(3.10) identical with step (2.17)～step (2.24);

(3.11) change step (3.1);

B. said two-way alternating current-direct current current transformer adopts three-phase half-bridge voltage type current transformer or three phase full bridge voltage-type current transformer; When said two-way alternating current-direct current current transformer was three-phase half-bridge voltage type current transformer, the first～the six tunnel drive signal of said generation was delivered to the first～the six tunnel drive signal interface of two-way alternating current-direct current current transformer respectively; When said two-way alternating current-direct current current transformer is three phase full bridge voltage-type current transformer; Said first via drive signal is delivered to the first, the four tunnel drive signal interface of two-way alternating current-direct current current transformer respectively; The second tunnel drive signal is delivered to second, third road drive signal interface of two-way alternating current-direct current current transformer respectively; The Third Road drive signal deliver to respectively two-way alternating current-direct current current transformer the 5th, octuple drive signal interface; The four tunnel drive signal is delivered to the 6th, the seven tunnel drive signal interface of two-way alternating current-direct current current transformer respectively; The five tunnel drive signal is delivered to the 9th, the ten two tunnel drive signal interfaces of two-way alternating current-direct current current transformer respectively, and the six tunnel drive signal is delivered to the tenth, the ten one tunnel drive signal interfaces of two-way alternating current-direct current current transformer respectively;

C. said bidirectional, dc current transformer adopts two-way Buck/Boost current transformer;

D. said battery pack adopts flow battery or ferric phosphate lithium cell.

2. parallel connection as claimed in claim 1 discharges and recharges power conversion system, it is characterized in that, in the controller islet operation module of said each subsystem:

(1). said active voltage proportionality coefficient K _VpdWith active voltage integral coefficient K _VidDeterministic process is:

(1.1) with K _VpdInitial value is taken as 0.72, K _VidInitial value is taken as 0;

(1.2) debug K earlier _Vpd, check three-phase alternating voltage u this moment _{A, b, c}Whether waveform vibrates, and is then to increase K _VpdEliminate until oscillating waveform, turn over journey (1.3); Otherwise directly turn over journey (1.3);

(1.3) fixing K _VpdValue is with K _VidBe taken as 1789, debugging K _Vid, check three-phase alternating voltage u this moment _{A, b, c}Whether waveform fluctuates, and is then to strengthen K _VidEliminate until fluctuation;

(2). said active current proportionality coefficient K _IpdWith active current integral coefficient K _IidDeterministic process is:

(2.1) with K _IpdInitial value is taken as 17.32, K _IidInitial value is taken as 0;

(2.2) debug K earlier _Ipd, check three-phase alternating current i this moment _{A, b, c}Whether waveform vibrates, and is then to increase K _IpdEliminate until oscillating waveform, turn over journey (2.3); Otherwise directly turn over journey (2.3);

(2.3) fixing K _IpdValue is with K _IidBe taken as 2.02 * 10 ⁵, debugging K _Iid, check three-phase alternating current i this moment _{A, b, c}Whether waveform fluctuates, and is then to strengthen K _IidEliminate until fluctuation;

(3). said busbar voltage proportionality coefficient K _VpdcWith busbar voltage integral coefficient K _VidcDeterministic process is:

(3.1) with K _VpdcInitial value is taken as 0.067, K _VidcInitial value is taken as 0;

(3.2) debug K earlier _Vpdc, check DC bus-bar voltage u this moment _DcWhether waveform vibrates, and is then to increase K _VpdcEliminate until oscillating waveform, turn over journey (3.3); Otherwise directly turn over journey (3.3);

(3.3) fixing K _VpdcValue is with K _VidcBe taken as 18.23, debugging K _Vidc, check DC bus-bar voltage u this moment _DcWhether waveform fluctuates, and is then to strengthen K _VidcEliminate until fluctuation;

(4). said battery current proportionality coefficient K _IpbatWith battery current integral coefficient K _IibatDeterministic process is:

(4.1) with K _IpbatInitial value is taken as 0.042, K _IibatInitial value is taken as 0;

(4.2) debug K earlier _Ipbat, check i Battery pack current i this moment _BatiWhether waveform vibrates, and is then to increase K _IpbatEliminate until oscillating waveform, turn over journey (4.3); Otherwise directly turn over journey (4.3);

(4.3) fixing K _IpbatValue is with K _IibatBe taken as 5.28, debugging K _Iibat, check i Battery pack current i this moment _BatiWhether waveform fluctuates, and is then to strengthen K _IibatEliminate until fluctuation;

(5). said frequency adjustment proportionality coefficient K _FpWith frequency adjustment integral coefficient K _FiDeterministic process is:

(5.1) with K _FpInitial value is taken as 3.73 * 10 ^-3, K _FiInitial value is taken as 0;

(5.2) debug K earlier _Fp, check the time that each subsystem output this moment active current reaches unanimity, if the time is greater than 2s then increase K _Fp, turn over journey (5.3); Otherwise directly turn over journey (5.3);

(5.3) fixing K _FpValue is with K _FiBe taken as 1.12 * 10 ^-3, debugging K _Fi, check the equal stream error of each subsystem output active current this moment, increase K _FiCan reduce the equal stream error of active current;

(6). said amplitude is regulated proportionality coefficient K _MpRegulate integral coefficient K with amplitude _MiDeterministic process is:

(6.1) with K _MpInitial value is taken as 3.73 * 10 ^-3, K _MiInitial value is taken as 0;

(6.2) debug K earlier _Mp, check the time that each subsystem output this moment reactive current reaches unanimity, if the time is greater than 2s then increase K _Mp, turn over journey (6.3); Otherwise directly turn over journey (6.3);

(6.3) fixing K _MpValue is with K _MiBe taken as 1.12 * 10 ^-3, debugging K _Mi, check the equal stream error of each subsystem output reactive current this moment, increase K _MiCan reduce the equal stream error of reactive current.

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