CN102638038B - 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 charge-discharge power conversion system

Technical field

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

Background technology

The peak-valley difference of urban distribution network expanding day and the distributed intermittent regenerative resource of being on the increase affect and become clear day by day power grid security.Meanwhile, increasing enterprise needs the higher quality of power supply to improve the qualification rate of its product; The department such as hospital, government 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 is high owing to having for battery energy storage, change working fast, less demanding, the geographical adaptable feature of power plant construction land used receives much concern.The battery energy storage station construction period is short, be easy to expansion, do 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, the research of the extensive battery energy storage technology of the positive Efforts To Develop of China, the safe and stable operation pattern at exploration battery charging and discharging station, to 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 corresponding control technology supporting with energy-storage system have also obtained significant progress.Existing parallel charge-discharge power conversion system adopts centralized control, principal and subordinate's control, distributed logic control and no control interconnections conventionally, that yet this type of control program cannot provide is highly reliable, the communication approach of two-forty, is generally only applicable to the parallel system that module spatial distribution is less.And existing parallel charge-discharge power conversion system generally consists of a plurality of subsystems, the battery of each subsystem is the battery pack by parallel connection forms again after a plurality of battery cell series connection, the group difference of this type of battery pack is larger, more strict to discharging and recharging control and the requirement of energy scheduling strategy.

The companies such as external ABB, DynaPower, Exergonix are devoted for years in the powerful energy conversion system of research and development, as the PCS100 ESS series energy storage converter device of ABB AB's research and development, system power can reach 5MW, but it adopts single step arrangement, can not adapt on a large scale battery terminal voltage, this battery types that just determines 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 charge-discharge power conversion system, solves the problem that existing parallel charge-discharge power conversion system capacity is little, communication reliability is low, coordination control is difficult, to realize the reliable and stable operation of high-power parallel system.

A kind of parallel charge-discharge power conversion system of the present invention, comprises host computer, a central control unit and N subsystem, 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 is connected with ac bus, and ac bus is connected to electrical network or is connected to local load by local switch by grid-connected switch; Described host computer is connected with central control unit by communication cable, central control unit by communication network and optical fiber respectively with the controller communication of each subsystem, N=1～10, is characterized in that:

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

(2) described central control unit, carries out following operation:

(1) mode decision step:

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

(1.2) if m=1 goes to step (3); Otherwise go to step (2);

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

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

(2.1) line voltage is detected and phase-locked acquisition electrical network amplitude V _g, synchronizing signal θ and mains frequency f _g;

(2.2) electric network state judgement:

Judge whether 264.4V≤V _g≤ 342.1V and 49.5Hz≤f _g≤ 50.5Hz, is that electrical network is normal condition, and closed grid-connected switch sends control model variable m=2, rotor step (2.3) by optical fiber to each subsystem; Otherwise electrical network is malfunction, to host computer, sends electric network fault signal, goes to step (1);

(2.3) wait for the active power value P of 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 _ifor SOC _iweights coefficient, k _i, k _xspan is 0～1,

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

(3) islet operation step, comprises following sub-step:

(3.1) disconnect grid-connected switch, by optical fiber, to each subsystem, send control model variable m=1; Utilize counter to obtain initial synchronisation signal

x is current time count value, and X=mod (10 ⁶/ 2 ^t), mod represents the value in bracket to round, the integer that T is 0～7, counter every 20 * 2 ^tns adds 1;

(3.2) according to the active-power P of each subsystem output _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) to each subsystem controller, send initial synchronisation signal, corresponding active power reference value P _refi, reactive power reference qref Q _refiwith initial output voltage amplitude V _mrefo=311V, rotor step (3.1);

(4) isolated island, to grid-connected switch step, comprises following sub-step:

(4.1) line voltage is detected and phase-locked acquisition electrical network amplitude V _g, synchronizing signal θ and mains frequency f _g;

(4.2) electric network state judgement:

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

(4.3) put initial synchronisation signal

put initial output voltage amplitude V _mrefo=V _g;

(4.4) closed grid-connected switch, and to each subsystem, send control model variable m=2 by optical fiber;

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

(5) grid-connected to isolated island switch step, comprise following sub-step:

(5.1) detect the active-power P of parallel charge-discharge power conversion system output _gand reactive power Q _g;

(5.2) disconnect grid-connected switch, and to each subsystem, send control model variable m=1, initial output voltage amplitude V by optical fiber _mrefo=311V, initial synchronisation signal

active power reference value

and reactive power reference qref

(3) described each subsystem all has bidirectional, dc current transformer, in each subsystem, isolating transformer connects two-way alternating current-direct current current transformer by switch, two-way alternating current-direct current current transformer connects bidirectional, dc current transformer by DC bus, bidirectional, dc current transformer is connected with battery pack, controller generates the first～six roads and drives signal to deliver to two-way alternating current-direct current current transformer, and controller generates the 7th, eight roads and drives signal to deliver to bidirectional, dc current transformer;

A. the controller of i subsystem comprises mode decision module, islet operation module, module is incorporated into the power networks; I=1～N;

(1) mode decision module is carried out following operation:

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

(1.2) periodically judging whether control model variable m equals work at present pattern variable n, is to go to step (1.4); Otherwise go to step (1.3);

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

(1.4) mode of operation variable n is judged:

N=1, turns (2) islet operation module;

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

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

(2.1) the initial three-phase alternating voltage u to 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 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 carried out phase-locked, obtains initial phase angle

(2.3) calculate phase angle

(2.4) utilize phase angle

carry out coordinate system conversion, by three-phase alternating voltage u under three phase static coordinate system _{a, b, ci}, three-phase alternating current i _{a, b, ci}be transformed to and under synchronous rotating frame, exchange active voltage u _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，

By u _{a, b, ci}, i _{a, b, ci}, u _dci, u _bati, i _batiby communication network, deliver to described central control unit, by P _iand Q _iby optical fiber, deliver to described central control unit;

(2.5) calculate active power error e _pi: e _pi=P _refi-P _i; Wherein, P _refithe active power reference value of i the subsystem providing 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 Proportional coefficient K _fp≤ 4.32 * 10 ^-3, 1.12 * 10 ^-3≤ frequency adjustment integral coefficient K _fi≤ 1.56 * 10 ^-3;

(2.7) calculate reactive power error e _qi: e _qi=Q _refi-Q _i; Wherein, Q _refithe reactive power reference qref of i the subsystem providing 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 providing for central control unit, 3.73 * 10 ^-3≤ amplitude regulates Proportional coefficient K _mp≤ 4.32 * 10 ^-3, 1.12 * 10 ^-3≤ amplitude regulates integral coefficient K _mi≤ 1.56 * 10 ^-3;

(2.9) calculate 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 Proportional coefficient K _vpd≤ 0.87,1789≤active voltage integral coefficient K _vid≤ 1973;

(2.11) calculate 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 Proportional coefficient K _ipd≤ 19.06,1.92 * 10 ⁵≤ active current integral coefficient K _iid≤ 2.13 * 10 ⁵;

(2.13) calculate 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 Proportional coefficient K _vpq=K _vpd; Reactive voltage integral coefficient K _viq=K _vid;

(2.15) calculate 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 Proportional coefficient K _ipq=K _ipd; Reactive current integral coefficient K _iiq=K _iid;

(2.17) by the u under synchronous rotating frame _rdiand u _rqibe transformed to a phase modulation voltage u under 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:

$\left[\begin{array}{c}{u}_{\mathrm{rai}}^{\&prime;}\\ u_{\mathrm{rbi}}^{\&prime;}\\ u_{\mathrm{rci}}^{\&prime;}\end{array}\right]=\left[\begin{array}{c}{u}_{\mathrm{rai}}\\ u_{\mathrm{rbi}}\\ u_{\mathrm{rci}}\end{array}\right]+{\mathrm{<figure-callout\; id="1"\; label="u\; zi"\; filenames="HDA0000145189700000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{zi}}\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right];$

Wherein, zero-sequence component u _zi=-[max (u _rai, u _rbi, u _rci)+min (u _rai, u _rbi, u _rci)]/2; The operation function that max and min are respectively maximizing and minimize;

(2.19) generate and drive signal:

By u ' _rai, u ' _rbi, u ' _rcibe 3kHz with frequency respectively, the triangular carrier signal that amplitude is 1 is compared, as u ' _raiwhile being greater than triangular carrier sample, the output first via drives signal, as u ' _raiduring lower than triangular carrier sample, export the second road and drive signal; As u ' _rbiwhile being greater than triangular carrier sample, output Third Road drives signal, as u ' _rbiduring lower than triangular carrier sample, output Si road drives signal; As u ' _rciwhile being greater than triangular carrier sample, output Wu road drives signal, as u ' _rciduring lower than triangular carrier sample, output Liu road drives signal;

Drive signal to deliver to two-way alternating current-direct current current transformer on the first～six tunnels that generate;

(2.20) calculate DC bus-bar voltage error e _vdci: e _vdci=u _dc ^*-u _dci; Wherein, u _dc ^*=700V;

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

I _bati ^*=K _vpdce _vdci+ K _vidc∫ e _vdcidt; Wherein, 0.067≤busbar voltage Proportional coefficient K _vpdc≤ 0.081; 18.23≤busbar voltage integral coefficient K _vidc≤ 22.06;

(2.22) calculate the battery current error e of 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 Proportional coefficient K _ipbat≤ 0.051,5.28≤battery current integral coefficient K _iibat≤ 6.39;

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

By u _rdciwith frequency be 10kHz, the sawtooth signal that amplitude is 1 is compared, and works as u _rdciwhile being greater than sawtooth signal instantaneous value, output Qi road drives signal, works as u _rdciduring lower than sawtooth signal instantaneous value, output Ba road drives signal;

Drive signal to deliver to bidirectional, dc current transformer on the 7th, eight tunnels that generate;

(2.25) go to step (2.1);

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

(3.1) the initial three-phase alternating voltage u to 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 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 carried out phase-locked, obtains phase angle theta _i;

(3.3) utilize phase angle theta _icarry out coordinate system conversion, by three-phase alternating voltage u under three phase static coordinate system _{a, b, ci}, three-phase alternating current i _{a, b, ci}be transformed to and under synchronous rotating frame, exchange active voltage u _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，

By u _{a, b, ci}, i _{a, b, ci}, u _dci, u _bati, i _batiby communication network, deliver to described central control unit, by P _iand Q _iby optical fiber, deliver to described central control unit;

(3.4) calculate active current reference value i _di ^*: i _di ^*=P _refi/ u _di;

Wherein, P _refifor the active power reference value being provided by central control unit;

(3.5) calculate 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 _refifor the reactive power reference qref being provided by central control unit;

(3.8) calculate 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) go to step (3.1);

B. described 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 described two-way alternating current-direct current current transformer is three-phase half-bridge voltage type current transformer, the first～six roads that the first～six tunnels of described generation drive signal to deliver to respectively two-way alternating current-direct current current transformer drive signaling interface, when described two-way alternating current-direct current current transformer is three phase full bridge voltage-type current transformer, the described first via drives signal to deliver to respectively first of two-way alternating current-direct current current transformer, Si road drives signaling interface, the second road drives signal to deliver to respectively second of two-way alternating current-direct current current transformer, Third Road drives signaling interface, Third Road drives signal to deliver to respectively the 5th of two-way alternating current-direct current current transformer, Ba road drives signaling interface, Si road drives signal to deliver to respectively the 6th of two-way alternating current-direct current current transformer, Qi road drives signaling interface, Wu road drives signal to deliver to respectively the 9th of two-way alternating current-direct current current transformer, Shi bis-roads drive signaling interface, Liu road drives signal to deliver to respectively the tenth of two-way alternating current-direct current current transformer, Shi mono-road drives signaling interface,

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

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

Described parallel charge-discharge power conversion system, is characterized in that, in the controller islet operation module of described each subsystem:

(1). described active voltage Proportional coefficient K _vpdwith active voltage integral coefficient K _viddeterministic process is:

(1.1) by K _vpdinitial value is taken as 0.72, K _vidinitial value is taken as 0;

(1.2) first debug K _vpd, check now three-phase alternating voltage u _{a, b, c}whether waveform vibrates, and is to increase K _vpduntil oscillating waveform is eliminated, turn over journey (1.3); Otherwise directly turn over journey (1.3);

(1.3) fixing K _vpdvalue, by K _vidbe taken as 1789, debugging K _vid, check now three-phase alternating voltage u _{a, b, c}whether waveform fluctuates, and is to strengthen K _viduntil fluctuation is eliminated;

(2). described active current Proportional coefficient K _ipdwith active current integral coefficient K _iiddeterministic process is:

(2.1) by K _ipdinitial value is taken as 17.32, K _iidinitial value is taken as 0;

(2.2) first debug K _ipd, check now three-phase alternating current i _{a, b, c}whether waveform vibrates, and is to increase K _ipduntil oscillating waveform is eliminated, turn over journey (2.3); Otherwise directly turn over journey (2.3);

(2.3) fixing K _ipdvalue, by K _iidbe taken as 2.02 * 10 ⁵, debugging K _iid, check now three-phase alternating current i _{a, b, c}whether waveform fluctuates, and is to strengthen K _iiduntil fluctuation is eliminated;

(3). described busbar voltage Proportional coefficient K _vpdcwith busbar voltage integral coefficient K _vidcdeterministic process is:

(3.1) by K _vpdcinitial value is taken as 0.067, K _vidcinitial value is taken as 0;

(3.2) first debug K _vpdc, check now DC bus-bar voltage u _dcwhether waveform vibrates, and is to increase K _vpdcuntil oscillating waveform is eliminated, turn over journey (3.3); Otherwise directly turn over journey (3.3);

(3.3) fixing K _vpdcvalue, by K _vidcbe taken as 18.23, debugging K _vidc, check now DC bus-bar voltage u _dcwhether waveform fluctuates, and is to strengthen K _vidcuntil fluctuation is eliminated;

(4). described battery current Proportional coefficient K _ipbatwith battery current integral coefficient K _iibatdeterministic process is:

(4.1) by K _ipbatinitial value is taken as 0.042, K _iibatinitial value is taken as 0;

(4.2) first debug K _ipbat, check now i Battery pack current i _batiwhether waveform vibrates, and is to increase K _ipbatuntil oscillating waveform is eliminated, turn over journey (4.3); Otherwise directly turn over journey (4.3);

(4.3) fixing K _ipbatvalue, by K _iibatbe taken as 5.28, debugging K _iibat, check now i Battery pack current i _batiwhether waveform fluctuates, and is to strengthen K _iibatuntil fluctuation is eliminated;

(5). described frequency adjustment Proportional coefficient K _fpwith frequency adjustment integral coefficient K _fideterministic process is:

(5.1) by K _fpinitial value is taken as 3.73 * 10 ^-3, K _fiinitial value is taken as 0;

(5.2) first debug K _fp, check the time that now each subsystem output active current reaches unanimity, if the time is greater than 2s, increase K _fp, turn over journey (5.3); Otherwise directly turn over journey (5.3);

(5.3) fixing K _fpvalue, by K _fibe taken as 1.12 * 10 ^-3, debugging K _fi, check the now equal stream error of each subsystem output active current, increase K _fican reduce the equal stream error of active current;

(6). described amplitude regulates Proportional coefficient K _mpregulate integral coefficient K with amplitude _mideterministic process is:

(6.1) by K _mpinitial value is taken as 3.73 * 10 ^-3, K _miinitial value is taken as 0;

(6.2) first debug K _mp, check the time that now each subsystem output reactive current reaches unanimity, if the time is greater than 2s, increase K _mp, turn over journey (6.3); Otherwise directly turn over journey (6.3);

(6.3) fixing K _mpvalue, by K _mibe taken as 1.12 * 10 ^-3, debugging K _mi, check the now equal stream error of each subsystem output reactive current, increase K _mican reduce the equal stream error of reactive current.

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

The present invention adopts heterarchical architecture, between host computer, central control unit and each subsystem controller, adopts high speed communication network to carry out exchanges data, and wherein, the host computer of top layer is responsible for man-machine interaction; 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 sending synchronizing signal and control command to each subsystem; The controller of each subsystem completes the bi-directional scheduling of current transformer energy flow and discharges and recharges control strategy.The present invention has that power system capacity is large, high, the fireballing advantage of communication reliability, by 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 has realized synchronous between each subsystem easily, thereby realizes that multiple subsystem is incorporated into the power networks, the seamless switching between multiple subsystem islet operation in parallel and this two kinds of operating modes.Be applicable to adopt the energy-storage system of large-capacity battery pack.

Accompanying drawing explanation

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

Fig. 2 is central control unit mode decision step schematic diagram;

Fig. 3 is that central control unit isolated island is to grid-connected switch step schematic diagram;

Fig. 4 is that central control unit is grid-connected to isolated island switch step schematic diagram;

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 present invention comprises host computer, central control unit and 10 subsystems, 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 is connected with ac bus, and ac bus is connected to electrical network or is connected to local load by local K switch L by grid-connected K switch g; Described host computer is connected with central control unit by communication cable, central control unit by communication network and optical fiber respectively with the controller communication of each subsystem, each subsystem controller is controlled the work of the two DC convertor of corresponding subsystem and AC/DC convertor.

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

Host computer passes through 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, described operational order comprises startup and shutdown; The value of described pattern input variable j is 1 or 2; When receiving the electric network fault signal of central control unit transmission by optical fiber, make pattern input variable j=1;

Central control unit carries out following operation:

(1) as shown in Figure 2, mode decision step, comprises following sub-step:

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

(1.2) if m=1 goes to step (3); Otherwise go to step (2);

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

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

(2.1) line voltage is detected and phase-locked acquisition electrical network amplitude V _g, synchronizing signal θ and mains frequency f _g;

(2.2) electric network state judgement:

Judge whether 264.4V≤V _g≤ 342.1V and 49.5Hz≤f _g≤ 50.5Hz, is that electrical network is normal condition, and closed grid-connected switch sends control model variable m=2, rotor step (2.3) by optical fiber to each subsystem; Otherwise electrical network is malfunction, to host computer, sends electric network fault signal, goes to step (1);

(2.3) wait for the active power value P of 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:

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

Wherein, SOC _ibe i subsystem battery pack state-of-charge, k _ifor SOC _iweights coefficient, k _i, k _xspan is 0～1,

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

(3) islet operation step, comprises following sub-step:

(3.1) disconnect grid-connected switch, by optical fiber, to each subsystem, send control model variable m=1; Utilize counter to obtain initial synchronisation signal

x is current time count value, and X=mod (10 ⁶/ 2 ^t), mod represents the value in bracket to round, the integer that T is 0～7, counter every 20 * 2 ^tns adds 1;

(3.2) according to the active-power P of each subsystem output _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:

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

(3.3) to each subsystem controller, send initial synchronisation signal, corresponding active power reference value P _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, to grid-connected switch step, comprises following sub-step:

(4.1) line voltage is detected and phase-locked acquisition electrical network amplitude V _g, synchronizing signal θ and mains frequency f _g;

(4.2) electric network state judgement:

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

(4.3) put initial synchronisation signal

put initial output voltage amplitude V _mrefo=V _g;

(4.4) closed grid-connected switch, and to each subsystem, send control model variable m=2 by optical fiber;

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

(5) as shown in Figure 4, grid-connected to isolated island switch step, comprise following sub-step:

(5.1) detect the active-power P of parallel charge-discharge power conversion system output _gand reactive power Q _g;

(5.2) disconnect grid-connected switch, and to each subsystem, send control model variable m=1, initial output voltage amplitude V by optical fiber _mrefo=311V, initial synchronisation signal

active power reference value

and reactive power reference qref

Each subsystem all has bidirectional, dc current transformer, in each subsystem, isolating transformer connects two-way alternating current-direct current current transformer by switch, two-way alternating current-direct current current transformer connects bidirectional, dc current transformer by DC bus, bidirectional, dc current transformer is connected with battery pack, controller generates the first～six roads and drives signal to deliver to two-way alternating current-direct current current transformer, and controller generates the 7th, eight roads and drives signal to deliver to bidirectional, dc current transformer;

The controller of i subsystem comprises mode decision module, islet operation module, module is incorporated into the power networks; I=1～N;

(1) mode decision module is carried out following operation:

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

(1.2) periodically judging whether control model variable m equals work at present pattern variable n, is to go to step (1.4); Otherwise go to step (1.3);

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

(1.4) mode of operation variable n is judged:

N=1, turns (2) islet operation module;

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

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

(2.1) the initial three-phase alternating voltage u to 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 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 carried out phase-locked, obtains initial phase angle

(2.3) calculate phase angle

(2.4) utilize phase angle

carry out coordinate system conversion, by three-phase alternating voltage u under three phase static coordinate system _{a, b, ci}, three-phase alternating current i _{a, b, ci}be transformed to and under synchronous rotating frame, exchange active voltage u _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，

By u _{a, b, ci}, i _{a, b, ci}, u _dci, u _bati, i _batiby communication network, deliver to described central control unit, by P _iand Q _iby optical fiber, deliver to described central control unit;

(2.5) calculate active power error e _pi: e _pi=P _refi-P _i; Wherein, P _refithe active power reference value of i the subsystem providing 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 reactive power error e _qi: e _qi=Q _refi-Q _i; Wherein, Q _refithe reactive power reference qref of i the subsystem providing 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 _mrefoifor 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 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 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 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 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) by the u under synchronous rotating frame _rdiand u _rqibe transformed to a phase modulation voltage u under 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:

$\left[\begin{array}{c}{u}_{\mathrm{rai}}^{\&prime;}\\ u_{\mathrm{rbi}}^{\&prime;}\\ u_{\mathrm{rci}}^{\&prime;}\end{array}\right]=\left[\begin{array}{c}{u}_{\mathrm{rai}}\\ u_{\mathrm{rbi}}\\ u_{\mathrm{rci}}\end{array}\right]+{\mathrm{<figure-callout\; id="1"\; label="u\; zi"\; filenames="HDA0000145189700000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{zi}}\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right];$

Wherein, zero-sequence component u _zi=-[max (u _rai, u _rbi, u _rci)+min (u _rai, u _rbi, u _rci)]/2; The operation function that max and min are respectively maximizing and minimize;

(2.19) generate and drive signal:

By u ' _rai, u ' _rbi, u ' _rcibe 3kHz with frequency respectively, the triangular carrier signal that amplitude is 1 is compared, as u ' _raiwhile being greater than triangular carrier sample, the output first via drives signal, as u ' _raiduring lower than triangular carrier sample, export the second road and drive signal; As u ' _rbiwhile being greater than triangular carrier sample, output Third Road drives signal, as u ' _rbiduring lower than triangular carrier sample, output Si road drives signal; As u ' _rciwhile being greater than triangular carrier sample, output Wu road drives signal, as u ' _rciduring lower than triangular carrier sample, output Liu road drives signal;

Drive signal to deliver to two-way alternating current-direct current current transformer on the first～six tunnels that generate;

(2.20) calculate DC bus-bar voltage error e _vdci: e _vdci=u _dc ^*-u _dci; Wherein, u _dc ^*=700V;

(2.21) calculate the output battery current reference value i of 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) calculate the battery current error e of 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 and drive signal:

By u _rdciwith frequency be 10kHz, the sawtooth signal that amplitude is 1 is compared, and works as u _rdciwhile being greater than sawtooth signal instantaneous value, output Qi road drives signal, works as u _rdciduring lower than sawtooth signal instantaneous value, output Ba road drives signal;

Drive signal to deliver to bidirectional, dc current transformer on the 7th, eight tunnels that generate;

(2.25) go to 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) the initial three-phase alternating voltage u to 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 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 carried out phase-locked, obtains phase angle theta _i;

(3.3) utilize phase angle theta _icarry out coordinate system conversion, by three-phase alternating voltage u under three phase static coordinate system _{a, b, ci}, three-phase alternating current i _{a, b, ci}be transformed to and under synchronous rotating frame, exchange active voltage u _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，

By u _{a, b, ci}, i _{a, b, ci}, u _dci, u _bati, i _batiby communication network, deliver to described central control unit, by P _iand Q _iby optical fiber, deliver to described central control unit;

(3.4) calculate active current reference value i _di ^*: i _di ^*=P _refi/ u _di;

Wherein, P _refifor the active power reference value being provided by central control unit;

(3.5) calculate 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 _refifor the reactive power reference qref being provided by central control unit;

(3.8) calculate 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) go to step (3.1).

Claims (2)

1. a parallel charge-discharge power conversion system, comprises host computer, a central control unit and N subsystem, 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 is connected with ac bus, and ac bus is connected to electrical network or is connected to local load by local switch by grid-connected switch; Described host computer is connected with central control unit by communication cable, central control unit by communication network and optical fiber respectively with the controller communication of each subsystem, N=1～10, is characterized in that:

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

(2) described central control unit, carries out following operation:

(1) mode decision:

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

(1.2) if m=1 goes to step (3); Otherwise go to step (2);

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

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

(2.1) line voltage is detected and phase-locked acquisition electrical network amplitude V _g, synchronizing signal θ and mains frequency f _g;

(2.2) electric network state judgement:

Judge whether 264.4V≤V _g≤ 342.1V and 49.5Hz≤f _g≤ 50.5Hz, is that electrical network is normal condition, and closed grid-connected switch sends control model variable m=2, rotor step (2.3) by optical fiber to each subsystem; Otherwise electrical network is malfunction, to host computer, sends electric network fault signal, goes to step (1);

(2.3) wait for the active power value P of 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:

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

Wherein, SOC _ibe i subsystem battery pack state-of-charge, k _ifor SOC _iweights coefficient, k _i, k _xspan is 0～1,

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

(3) islet operation step, comprises following sub-step:

(3.1) disconnect grid-connected switch, by optical fiber, to each subsystem, send control model variable m=1; Utilize counter to obtain initial synchronisation signal

x is current time count value, and X=mod (10 ⁶/ 2 ^t), mod represents the value in bracket to round, the integer that T is 0～7, counter every 20 * 2 ^tns adds 1;

(3.2) according to the active-power P of each subsystem output _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:

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

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

(4) isolated island, to grid-connected switch step, comprises following sub-step:

(4.1) line voltage is detected and phase-locked acquisition electrical network amplitude V _g, synchronizing signal θ and mains frequency f _g;

(4.2) electric network state judgement:

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

(4.3) put initial synchronisation signal

put initial output voltage amplitude V _mrefo=V _g;

(4.4) closed grid-connected switch, and to each subsystem, send control model variable m=2 by optical fiber;

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

(5) grid-connected to isolated island switch step, comprise following sub-step:

(5.1) detect the active-power P of parallel charge-discharge power conversion system output _gand reactive power Q _g;

(5.2) disconnect grid-connected switch, and to each subsystem, send control model variable m=1, initial output voltage amplitude V by optical fiber _mrefo=311V, initial synchronisation signal

active power reference value

and reactive power reference qref

(3) described each subsystem all has bidirectional, dc current transformer, in each subsystem, isolating transformer connects two-way alternating current-direct current current transformer by switch, two-way alternating current-direct current current transformer connects bidirectional, dc current transformer by DC bus, bidirectional, dc current transformer is connected with battery pack, controller generates the first～six roads and drives signal to deliver to two-way alternating current-direct current current transformer, and controller generates the 7th, eight roads and drives signal to deliver to bidirectional, dc current transformer;

A. the controller of i subsystem comprises mode decision module, islet operation module, module is incorporated into the power networks; I=1～N;

(1) mode decision module is carried out following operation:

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

(1.2) periodically judging whether control model variable m equals work at present pattern variable n, is to go to step (1.4); Otherwise go to step (1.3);

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

(1.4) mode of operation variable n is judged:

N=1, turns (2) islet operation module;

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

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

(2.1) the initial three-phase alternating voltage u to 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 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 carried out phase-locked, obtains initial phase angle

(2.3) calculate phase angle

(2.4) utilize phase angle

carry out coordinate system conversion, by three-phase alternating voltage u under three phase static coordinate system _{a, b, ci}, three-phase alternating current i _{a, b, ci}be transformed to and under synchronous rotating frame, exchange active voltage u _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，

By u _{a, b, ci}, i _{a, b, ci}, u _dci, u _bati, i _batiby communication network, deliver to described central control unit, by P _iand Q _iby optical fiber, deliver to described central control unit;

(2.5) calculate active power error e _pi: e _pi=P _refi-P _i; Wherein, P _refithe active power reference value of i the subsystem providing 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 Proportional coefficient K _fp≤ 4.32 * 10 ^-3, 1.12 * 10 ^-3≤ frequency adjustment integral coefficient K _fi≤ 1.56 * 10 ^-3;

(2.7) calculate reactive power error e _qi: e _qi=Q _refi-Q _i; Wherein, Q _refithe reactive power reference qref of i the subsystem providing for central control unit;

(2.8) calculate output voltage amplitude reference value V _refmi: V _refmi=V _mrefoi+ K _mpe _qi+ K _mi∫ e _qidt; Wherein, V _mrefoithe initial output voltage amplitude providing for central control unit, 3.73 * 10 ^-3≤ amplitude regulates Proportional coefficient K _mp≤ 4.32 * 10 ^-3, 1.12 * 10 ^-3≤ amplitude regulates integral coefficient K _mi≤ 1.56 * 10 ^-3;

(2.9) calculate 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 Proportional coefficient K _vpd≤ 0.87,1789≤active voltage integral coefficient K _vid≤ 1973;

(2.11) calculate 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 Proportional coefficient K _ipd≤ 19.06,1.92 * 10 ⁵≤ active current integral coefficient K _iid≤ 2.13 * 10 ⁵;

(2.13) calculate 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 Proportional coefficient K _vpq=K _vpd; Reactive voltage integral coefficient K _viq=K _vid;

(2.15) calculate 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 Proportional coefficient K _ipq=K _ipd; Reactive current integral coefficient K _iiq=K _iid;

(2.17) by the u under synchronous rotating frame _rdiand u _rqibe transformed to a phase modulation voltage u under 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:

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

Wherein, zero-sequence component u _zi=-[max (u _rai, u _rbi, u _rci)+min (u _rai, u _rbi, u _rci)]/2; The operation function that max and min are respectively maximizing and minimize;

(2.19) generate and drive signal:

By u ' _rai, u ' _rbi, u ' _rcibe 3kHz with frequency respectively, the triangular carrier signal that amplitude is 1 is compared, as u ' _raiwhile being greater than triangular carrier sample, the output first via drives signal, as u ' _raiduring lower than triangular carrier sample, export the second road and drive signal; As u ' _rbiwhile being greater than triangular carrier sample, output Third Road drives signal, as u ' _rbiduring lower than triangular carrier sample, output Si road drives signal; As u ' _rciwhile being greater than triangular carrier sample, output Wu road drives signal, as u ' _rciduring lower than triangular carrier sample, output Liu road drives signal;

Drive signal to deliver to two-way alternating current-direct current current transformer on the first～six tunnels that generate;

(2.20) calculate DC bus-bar voltage error e _vdci: e _vdci=u _dc ^*-u _dci; Wherein, u _dc ^*=700V;

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

I _bati ^*=K _vpdce _vdci+ K _vidc∫ e _vdcidt; Wherein, 0.067≤busbar voltage Proportional coefficient K _vpdc≤ 0.081; 18.23≤busbar voltage integral coefficient K _vidc≤ 22.06;

(2.22) calculate the battery current error e of 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 Proportional coefficient K _ipbat≤ 0.051,5.28≤battery current integral coefficient K _iibat≤ 6.39;

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

By u _rdciwith frequency be 10kHz, the sawtooth signal that amplitude is 1 is compared, and works as u _rdciwhile being greater than sawtooth signal instantaneous value, output Qi road drives signal, works as u _rdciduring lower than sawtooth signal instantaneous value, output Ba road drives signal;

Drive signal to deliver to bidirectional, dc current transformer on the 7th, eight tunnels that generate;

(2.25) go to step (2.1);

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

(3.1) the initial three-phase alternating voltage u to 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 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 carried out phase-locked, obtains phase angle theta _i;

(3.3) utilize phase angle theta _icarry out coordinate system conversion, by three-phase alternating voltage u under three phase static coordinate system _{a, b, ci}, three-phase alternating current i _{a, b, ci}be transformed to and under synchronous rotating frame, exchange active voltage u _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，

By u _{a, b, ci}, i _{a, b, ci}, u _dci, u _bati, i _batiby communication network, deliver to described central control unit, by P _iand Q _iby optical fiber, deliver to described central control unit;

(3.4) calculate active current reference value i _di ^*: i _di ^*=P _refi/ u _di;

Wherein, P _refifor the active power reference value being provided by central control unit;

(3.5) calculate 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 _refifor the reactive power reference qref being provided by central control unit;

(3.8) calculate 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) go to step (3.1);

B. described 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 described two-way alternating current-direct current current transformer is three-phase half-bridge voltage type current transformer, the first～six roads that the first～six tunnels of described generation drive signal to deliver to respectively two-way alternating current-direct current current transformer drive signaling interface, when described two-way alternating current-direct current current transformer is three phase full bridge voltage-type current transformer, the described first via drives signal to deliver to respectively first of two-way alternating current-direct current current transformer, Si road drives signaling interface, the second road drives signal to deliver to respectively second of two-way alternating current-direct current current transformer, Third Road drives signaling interface, Third Road drives signal to deliver to respectively the 5th of two-way alternating current-direct current current transformer, Ba road drives signaling interface, Si road drives signal to deliver to respectively the 6th of two-way alternating current-direct current current transformer, Qi road drives signaling interface, Wu road drives signal to deliver to respectively the 9th of two-way alternating current-direct current current transformer, Shi bis-roads drive signaling interface, Liu road drives signal to deliver to respectively the tenth of two-way alternating current-direct current current transformer, Shi mono-road drives signaling interface,

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

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

2. parallel charge-discharge power conversion system as claimed in claim 1, is characterized in that, in the controller islet operation module of described each subsystem:

(1). described active voltage Proportional coefficient K _vpdwith active voltage integral coefficient K _viddeterministic process is:

(1.1) by K _vpdinitial value is taken as 0.72, K _vidinitial value is taken as 0;

(1.2) first debug K _vpd, check now three-phase alternating voltage u _{a, b, c}whether waveform vibrates, and is to increase K _vpduntil oscillating waveform is eliminated, turn over journey (1.3); Otherwise directly turn over journey (1.3);

(1.3) fixing K _vpdvalue, by K _vidbe taken as 1789, debugging K _vid, check now three-phase alternating voltage u _{a, b, c}whether waveform fluctuates, and is to strengthen K _viduntil fluctuation is eliminated;

(2). described active current Proportional coefficient K _ipdwith active current integral coefficient K _iiddeterministic process is:

(2.1) by K _ipdinitial value is taken as 17.32, K _iidinitial value is taken as 0;

(2.2) first debug K _ipd, check now three-phase alternating current i _{a, b, c}whether waveform vibrates, and is to increase K _ipduntil oscillating waveform is eliminated, turn over journey (2.3); Otherwise directly turn over journey (2.3);

(2.3) fixing K _ipdvalue, by K _iidbe taken as 2.02 * 10 ⁵, debugging K _iid, check now three-phase alternating current i _{a, b, c}whether waveform fluctuates, and is to strengthen K _iiduntil fluctuation is eliminated;

(3). described busbar voltage Proportional coefficient K _vpdcwith busbar voltage integral coefficient K _vidcdeterministic process is:

(3.1) by K _vpdcinitial value is taken as 0.067, K _vidcinitial value is taken as 0;

(3.2) first debug K _vpdc, check now DC bus-bar voltage u _dcwhether waveform vibrates, and is to increase K _vpdcuntil oscillating waveform is eliminated, turn over journey (3.3); Otherwise directly turn over journey (3.3);

(3.3) fixing K _vpdcvalue, by K _vidcbe taken as 18.23, debugging K _vidc, check now DC bus-bar voltage u _dcwhether waveform fluctuates, and is to strengthen K _vidcuntil fluctuation is eliminated;

(4). described battery current Proportional coefficient K _ipbatwith battery current integral coefficient K _iibatdeterministic process is:

(4.1) by K _ipbatinitial value is taken as 0.042, K _iibatinitial value is taken as 0;

(4.2) first debug K _ipbat, check now i Battery pack current i _batiwhether waveform vibrates, and is to increase K _ipbatuntil oscillating waveform is eliminated, turn over journey (4.3); Otherwise directly turn over journey (4.3);

(4.3) fixing K _ipbatvalue, by K _iibatbe taken as 5.28, debugging K _iibat, check now i Battery pack current i _batiwhether waveform fluctuates, and is to strengthen K _iibatuntil fluctuation is eliminated;

(5). described frequency adjustment Proportional coefficient K _fpwith frequency adjustment integral coefficient K _fideterministic process is:

(5.1) by K _fpinitial value is taken as 3.73 * 10 ^-3, K _fiinitial value is taken as 0;

(5.2) first debug K _fp, check the time that now each subsystem output active current reaches unanimity, if the time is greater than 2s, increase K _fp, turn over journey (5.3); Otherwise directly turn over journey (5.3);

(5.3) fixing K _fpvalue, by K _fibe taken as 1.12 * 10 ^-3, debugging K _fi, check the now equal stream error of each subsystem output active current, increase K _fican reduce the equal stream error of active current;

(6). described amplitude regulates Proportional coefficient K _mpregulate integral coefficient K with amplitude _mideterministic process is:

(6.1) by K _mpinitial value is taken as 3.73 * 10 ^-3, K _miinitial value is taken as 0;

(6.2) first debug K _mp, check the time that now each subsystem output reactive current reaches unanimity, if the time is greater than 2s, increase K _mp, turn over journey (6.3); Otherwise directly turn over journey (6.3);

(6.3) fixing K _mpvalue, by K _mibe taken as 1.12 * 10 ^-3, debugging K _mi, check the now equal stream error of each subsystem output reactive current, increase K _mican reduce the equal stream error of reactive current.

Images