CN104868762B - A kind of electric power electric transformer and its control method of scattered energy storage - Google Patents

A kind of electric power electric transformer and its control method of scattered energy storage Download PDF

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Publication number
CN104868762B
CN104868762B CN201510303821.7A CN201510303821A CN104868762B CN 104868762 B CN104868762 B CN 104868762B CN 201510303821 A CN201510303821 A CN 201510303821A CN 104868762 B CN104868762 B CN 104868762B
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voltage
power
current
electric
energy
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CN104868762A (en
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周柯
盘宏斌
王凯
熊诵辉
孙志媛
刘程辉
杨理才
周卫
刘默斯
刘光时
王晓明
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Hunan University
Electric Power Research Institute of Guangxi Power Grid Co Ltd
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Hunan University
Electric Power Research Institute of Guangxi Power Grid Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The present invention relates to a kind of electric power electric transformer and its control method of scattered energy storage, the electric power electric transformer includes power cell and output module, and the power cell includes H bridge modules, energy-storage module, isolation module；The energy-storage module includes a Buck Boost, filter inductance and battery, battery is connected by filter inductance with Buck Boosts, the present invention proposes and employs scattered energy storage technology, ensure that the energy that electric power electric transformer is enough under special operation condition is supported, and the use of high capacity cell is avoided, improve electric power electric transformer operation stability；Energy-storage battery uses IAI interfaces, realizes and is decoupled with the active power of DC side energy.

Description

A kind of electric power electric transformer and its control method of scattered energy storage
Background technology
As network system develops, traditional power transformer gradually manifests some shortcomings, such as：During load excessive, it can lead Cause output voltage to decline, produce harmonic wave；When either original side or pair side break down, opposite side can all be affected；Function It is single, without functions such as voltage-regulation, PFC and power flow controls.
Electric power electric transformer (Power Electronic Transformer, PET) is recently as semiconductor skill The development of art and the novel electric power transformer progressively to grow up, the advantages of it takes full advantage of current transformer and high frequency transformer, The shortcomings that overcoming traditional transformer, the work(such as Fault Isolation, utility power quality control, distributed DC power access can also be realized Can, meet the demand of the modern intelligent grid construction such as active power network and microgrid, quickly grow.But it is unable in offset voltage It is disconnected, it is also helpless to depth Voltage Drop.Electric power electric transformer is as the subordinate such as major network and active distribution network or microgrid electricity The interface of net, when bad working environments occurs in major network, for example voltage fluctuates widely or fallen, it is necessary to ensure that subordinate's power network can be steady Spend unusual service condition；When major network breaks down suddenly, it is necessary to ensure that subordinate's power network can smooth off-grid operation.It is improper in major network Subordinate's power network normal work is ensured during work, electric power electric transformer is gone back necessary not only for the control function of high dynamic response Enough energy are needed to support.For the energy storage demand of electric power electric transformer, the country has gradually spread out research, and proposes Some energy storage methods.
Prior art is the low-voltage direct bus using electric power electric transformer, and super capacitor storage is accessed on bus Can system, DC/DC power conversion circuits use between energy-storage system and bus, are controlled accordingly, realize super capacitor and Discharge and recharge between dc bus.The shortcomings that prior art：(1) super capacitor centralized energy storage, energy density is than general storage Energy battery is small；(2) extra DC/DC power conversion circuits are added between energy-storage system and electric power electric transformer, need two sets Control system, and cost is high.(3) isolation level uses full bridge structure, and switch tube voltage stress is difficult to balance, electric current and voltage control It is indifferent.
The content of the invention
For overcome the deficiencies in the prior art, realized it is an object of the invention to provide a kind of by scattered energy-storage units The electric power electric transformer of energy storage.The present invention can ensure that the energy that electric power electric transformer is enough under special operation condition is supported, and Avoid the use of high capacity cell.
In order to realize the purpose of the present invention, technical scheme is as follows：
A kind of electric power electric transformer of scattered energy storage, it is characterised in that：It is whole that the electric power electric transformer includes cascade Flow level, scattered energy storage stage, isolation level, output stage；
Wherein, each phase of the input of the electric power electric transformer all accesses the input of H bridge modules, H bridge modules Output end connected with the input of corresponding energy-storage module, the output end of energy-storage module and corresponding isolation level Input connects；The H bridge modules, energy-storage module corresponding with H bridge modules and isolation module corresponding with energy-storage module composition Power cell；Electric power electric transformer each it is single-phase on access n power cell and an output module, H bridge moulds Input of the input of block as power cell, the input of power cell are connected with power network, cascade Connection in phase, alternate star Shape connects；The output end of isolation module is the output end of power cell, and the output end of power cell is in parallel, defeated with output module Enter end connection；
All H bridge modules on each is single-phase form this it is single-phase on cascade rectifier level, it is all on each is single-phase Energy-storage module form this it is single-phase on scattered energy storage stage, all isolation modules on each is single-phase form this it is single-phase on isolation Level, output stage are made up of an output module.
The H bridge modules are the controllable full bridge rectifier being made up of four IGBT with inverse parallel diode.
The energy-storage module includes a Buck/Boost converter, filter inductance and battery, and battery passes through filtering Inductance is connected with buck/boost converters.
The isolation module is bi-directional half bridge converter, and the both sides of bi-directional half bridge converter are symmetrical structure, left and right two Half-bridge is connected by the high frequency transformer of centre.
The output module is full-bridge DC/AC inverters.
The discharge and recharge of described scattered energy storage stage control energy-storage battery, under main power network nominal situation, energy-storage battery is carried out Charging, until quantity of electric charge percentage SoC reaches rated value, into poised state；Under poised state, a charging-discharging cycle is controlled The balance of the interior energy-storage battery quantity of electric charge；Main power network is when short time voltage is interrupted or depth is fallen, control energy-storage battery electric discharge.
The rate-determining steps of cascade rectifier level include as follows：
Step S1：The virtual voltage of sampling cascade every grade of H bridge module of rectification stageK represents phase (k ∈ a, b, c), and i is represented Series (1~n of i ∈), asks for virtual voltage average value vdc；
Step S2：Rectification stage is per step voltage nominal reference componentThe virtual voltage obtained by step (1) is subtracted through subtracter Average value vdc, obtain voltage error component Δ vdc；
Step S3：Voltage error component Δ vdcCurrent on line side direct current active component reference value is drawn after PI controllers
Step S4：Calculate power network current active component actual value isdWith reactive component actual value isq；
Step S5：The current on line side direct current active component reference value that step S3 is obtainedSubtracted through subtracter obtained by step S4 Power network current active component actual value isdObtain current on line side direct current active component margin of error Δ isd；
Step S6：Current on line side direct current active component margin of error Δ isdBy obtaining active point of line voltage after PI controllers Measure reference value
Step S7：Given power network current reactive component reference valueSubtract idle point of the power network current of step S4 acquisitions Measure actual value isqObtain current on line side direct current reactive power error amount Δ isq；
Step S8：Current on line side direct current reactive power error amount Δ isqJoined by obtaining line voltage reactive component after PI controllers Examine value
Step S9：The line voltage active component reference value that step (8) obtainsWith the power network electricity obtained with step (10) Press reactive component reference valueThree-phase modulations voltage is obtained after dq/abc is converted
Step S10：Calculate voltage amendment operand V0；
Step S11：The three-phase modulations voltage that step (11) is obtainedStep (15) acquisition is individually subtracted Voltage amendment operand V0Try to achieve the modulated signal of every phase
Step S12：Calculate each every grade H bridge submodules voltage correction factor rki；
Step S13：By the modulated signal of the step S11 every phases obtainedH bridges submodule electricity is multiplied by respectively Pressure correction factor rkiTry to achieve the drive signal of each IGBT pipes
The step S4 includes：
Step S41：Sample line voltage and obtain three-phase voltage value vsa, vsb, vsc, sampling power network current acquisition three-phase current Value isa, isb, isc；
Step S42：Step (4) is sampled into gained line voltage vsa, vsb, vscLock phase angle is obtained after synchronized lock phase module θ；
Step S43：The electric current i that step (4) obtainssa, isb, iscBecome with the lock phase angle theta that step (5) obtains by abc/dq Power network current active component actual value i is tried to achieve after changingsdWith reactive component actual value isq；
The step S10 includes：
Step S101：Detect rectification stage items power Pa, Pb, Pc；
Step S102：According to formulaTry to achieve mean power Pav；
Step S103：The every power P obtained with step (12)a, Pb, PcDifference divided by step (13) averaging of income power Pav, try to achieve each Power Correction Factor ra, rb, rc；
Step S104：The three-phase modulations voltage that step (11) is tried to achieveEach tried to achieve with step (14) Power Correction Factor ra, rb, rcBring formula into In try to achieve voltage amendment operand V0；
The circuit of described energy-storage battery discharge and recharge includes a switching and switched, two adders, two subtracters, and two Individual proportional controller, two integrators.
The process of the discharge and recharge of energy-storage battery comprises the following steps：
Step (1)：Network operation situation is detected, network operation situation is divided into nominal situation and damage.It is improper Situation refers to electric line voltage short interruptions or voltage depth is fallen；
Step (2)：As step (1) detects, network operation is normal, then switching switch is switched to charge mode.Power network is to electric power storage Pond is charged, and is charged to required rated value；
Step (3)：Fall as step (1) detects line voltage short interruptions or voltage depth, then switch switch and be switched to Charge mode.Energy storage battery discharges, and maintains the transformer rated output power；
Step (2) described charge control, detailed process are：
①：Energy-storage battery charging charge reference valueEnergy-storage battery electric charge actual charge value SoC is subtracted through subtracterki Draw energy-storage battery charge error component Δ SoCki；
②：Energy-storage battery charge error component Δ SoCkiThe power back-off margin of error is drawn through proportional controller
③：The power back-off margin of errorWith charge powerIt is superimposed after integrated device and just obtains energy-storage battery actual charge value SoCki；
By above-mentioned quantity of electric charge outer shroud and a power inner ring double-closed-loop control, energy-storage battery is charged to required specified Value；
Step (3) described control of discharge, detailed process are：
1. power needed for calculating electric power electric transformer, obtains power command value
②Electric power electric transformer actual power value is subtracted through subtracterDraw the discharge power margin of error
3. the discharge power margin of errorPassing ratio controller draws energy-storage battery charge compensation margin of error Δ SoCki；
④ΔSoCkiWith energy-storage battery electric charge SoCkiAfter superposition electric power electric transformer actual power is obtained through integrator Value
By above-mentioned power outer shroud and quantity of electric charge inner ring double-closed-loop control, battery discharging, electric power electric transformer obtains Required rated output power；
Above-mentioned SoC is electric charge percentage, and it characterizes the state of charge of energy-storage battery,For the specified electricity of energy-storage battery Lotus amount.
Isolation class control process comprises the following steps：
Step (1) isolation level output currentsInstructed with output-current ratingCurrent error letter is obtained through subtracter Number Δ I0；
Step (2) current error signals obtain duty cycle signals D through current controllerki；
Step (3) duty cycle signals DkiIt is modulated to draw the on high-tension side switching tube drive signal S of isolation levelP；
The on high-tension side switching tube drive signal S of step (4) isolation levelsPBy phase shift θkiDraw the driving letter of low pressure side pipe Number SS；
The switching signal S that step (5) is drawnPAnd SSDrive the switching tube work of isolation level.
Output class control process comprises the following steps：
Step (1)：Output voltage DC component reference instruction valueWith output voltage DC component actual valueThrough subtraction Device draws voltage error signal
Step (2)：Voltage error signalCurrent signal is drawn by PI controllers
Step (3)：Output voltage actual valueIt is multiplied by ωbCfDraw couple current
Step (4)：By load current DC componentSubtract the current signal obtained by step (2)Obtained by step (3) Couple currentDraw electric current loop reference instruction value
Step (5)：By electric current loop reference instruction value obtained by step (4)With output current DC component actual valueThrough subtracting Musical instruments used in a Buddhist or Taoist mass draws current error signal
Step (6)：Current error signalVoltage signal is drawn by PI controllers
Step (7)：Output current actual valueIt is multiplied by ωbLmDraw coupled voltages
Step (8)：By output voltage DC component actual valueSubtract the voltage signal obtained by step (6)And step (7) coupled voltages obtained byDraw modulation voltage ud；
Step (9)：Output voltage DC component reference instruction valueWith output voltage DC component actual valueThrough subtraction Device draws voltage error signal
Step (10)：Voltage error signalCurrent signal is drawn by PI controllers
Step (11)：Output voltage actual valueIt is multiplied by ωbCfDraw couple current
Step (12)：By load current DC componentSubtract the current signal obtained by step (10)With step (11) institute The coupled voltages obtainedDraw electric current loop reference instruction value
Step (13)：By electric current loop reference instruction value obtained by step (12)With output current DC component actual valueThrough Subtracter draws current error signal
Step (14)：Current error signalVoltage signal is drawn by PI controllers
Step (15)：Output current actual valueIt is multiplied by ωbLmDraw coupled voltages
Step (16)：By output voltage DC component actual valueSubtract the voltage signal obtained by step (14)And step Suddenly the coupled voltages obtained by (15)Draw modulation voltage uq；
Step (17)：By modulation voltage u obtained by step (8)dWith step (16) gained modulation voltage uqBy dq/abc contravariant Drive signal, the pipe work of driving inverter switching device are produced after changing；
Described LmFor inverter filtering inductance, CfFor inverter filtering electric capacity, ωbFor inverter output voltage angular frequency.
The present invention operation principle be：Main power network alternating current is by (power after cascade rectifier level progress voltage and Power Control Control includes cascaded H-bridges intermodule power-balance control in alternate power-balance control and phase), the levitating type DC electricity stablized PressureWherein, k represents phase (k ∈ a, b, c), and i represents series (1~n of i ∈), and the direct current total quantity of suspension is 3n.
Scattered energy storage stage is controlled the discharge and recharge of energy-storage battery by IAI circuits, protected using IAI circuits access energy-storage battery The energy support needed for electric power electric transformer under major network damage is demonstrate,proved, power buffer can also be used as to reduce due to work( Electric power electric transformer voltage pulsation caused by rate fluctuation, charges to energy-storage battery under nominal situation.Meanwhile pass through IAI Current control, energy-storage battery is set to be decoupled with DC side energy active power.3n energy-storage battery component dissipates access and it also avoid collecting The use of middle high capacity cell, reduce control difficulty.
The DHB structures of isolation level realize power in transformer high-voltage DC side (HV) and low-voltage direct side by phase shifting control (LV) two-way flow, i.e. H2L patterns.Meanwhile two pulse waves are filtered out by resonant controller, and ensure the output of low current ripple, it is real The thermal stress balance of existing switching device, strengthens current output capability.
Output stage DC/AC full-bridge inverters use the double-closed-loop control of inductive current inner ring and capacitance voltage outer shroud, here Inductance and electric capacity be derived from LC filter circuits.Inductive current inner ring can quickly suppress load disturbance influence, obtain preferably system System dynamic response performance；Outer voltage can improve output voltage waveforms, improve output accuracy.
The beneficial effect that technical solution of the present invention is brought
(1) electric power electric transformer realizes energy storage, ensures that the energy that electric power electric transformer is enough under special operation condition is supported. When falling such as major network voltage depth, electric power electric transformer and its subordinate's power network remain to stable operation.
(2) the scattered access of energy-storage battery, avoids the use of high capacity cell.
(3) fluctuation of electric power electric transformer internal power, stable DC side voltage can be buffered by disperseing the battery of access.
(4) IAI interfaces are used between rectification stage and energy-storage battery, realize active power decoupling and more simple control System.
(5) isolation level uses half-bridge structure, while realizing the two-way flow of power, balance cock tube voltage stress, carries The high fan-out capability of electric power electric transformer.
Brief description of the drawings
Fig. 1 is the overall topology figure of the electric power electric transformer preferred embodiment of the scattered energy storage of the present invention；
Fig. 2 is the power cell topology diagram in the electric power electric transformer of the scattered energy storage of the present invention；
Fig. 3 is the cascade rectifier level control figure in the electric power electric transformer of the scattered energy storage of the present invention；
Fig. 4 is the alternate power-balance control figure in the electric power electric transformer of the scattered energy storage of the present invention；
Fig. 5 is the power-balance control that the present invention disperses intermodules at different levels in the phase in the electric power electric transformer of energy storage Figure；
Fig. 6 is the energy-storage battery charge and discharge control block diagram in the electric power electric transformer of the scattered energy storage of the present invention；
Fig. 7 is the isolation level control block diagram in the electric power electric transformer of the scattered energy storage of the present invention；
Fig. 8 is that the kth phase i-stage transformer both sides switch function in the electric power electric transformer of the scattered energy storage of the present invention moves Phase schematic diagram；
Fig. 9 is the three-phase inverter uneoupled control figure in the electric power electric transformer of the scattered energy storage of the present invention.
Embodiment
With reference to the accompanying drawings and examples, the embodiment of the present invention is described further.Following examples are only For clearer explanation technical scheme, and can not be limited the scope of the invention with this.
As shown in figure 1, a kind of electric power electric transformer of scattered energy storage is made up of quaternary structure：Cascade rectifier level, disperse Energy storage stage, isolation level and output stage.Every grade of specific embodiment is as follows：
(1) cascade rectifier level
Cascade rectifier level controller is by outer shroud voltage regulator, inner ring current tracking device, power governor, Phase-Locked Synchronous machine The modules such as structure form, as shown in Figure 3.The DC voltage to suspend is gathered, average value v is obtained after calculatingdc, with reference voltage vrefThan Relatively and after PI is adjusted, meritorious reference current is obtainedIt is idle with reference to electricity to ensure the unity power factor of input current StreamTake zero.Inner ring current tracking device controls quick tracking of the actual current to instruction current, so as to realize that cascade rectifier level is defeated Enter the control of current waveform and phase.Command signal is obtained after the control of inner ring current tracking devicePhase-Locked Synchronous The phase signal of mechanism output is used to provide voltage vector oriented control and trigger pulse generates required reference phase.
Due to DC voltage average value vdcThe active power that comparison with reference voltage does not account for each intermodule is uneven, To ensure the alternate power-balance with intermodules at different levels in phase of cascade rectifier level, the modulated signal that current inner loop is drawn can't be straight Driving switch pipe is connect, to carry out Power Control.Specific control block diagram such as Fig. 4, Fig. 5.
In alternate power-balance control, each phase power P is detected firsta, Pb, Pc, obtain mean power Pav, then pass through voltage Amendment computing cascades rectification stage three-phase alternating current side voltage to balance, so as to control the inflow power of three-phase synchronous.Wherein be averaged work( Rate PavWith voltage amendment operand V0Respectively as shown in formula 1 and formula 2.
In the balance control of phase internal power, by suspended voltage actual values at different levels and reference value relatively after, PI adjusts to obtain straight Flow side voltage static difference compensation rate vki, then by introducing modular powers at different levels in the balance phase of unit feed-forward voltage coefficient 1.
Specific rate-determining steps are as follows：
Step (1)：The virtual voltage of sampling cascade every grade of H bridge module of rectification stageK represents phase (k ∈ a, b, c), and i is represented Series (1~n of i ∈), asks for virtual voltage average value vdc。
Step (2)：Rectification stage is per step voltage nominal reference componentThe virtual voltage obtained by step (1) is subtracted through subtracter Average value vdc, obtain voltage error component Δ vdc。
Step (3)：Voltage error component Δ vdcCurrent on line side direct current active component reference value is drawn after PI controllers
Step (4)：Sample line voltage and obtain three-phase voltage value vsa, vsb, vsc, sampling power network current acquisition three-phase current Value isa, isb, isc。
Step (5)：Step (4) is sampled into gained line voltage vsa, vsb, vscLock phase angle is obtained after synchronized lock phase module θ。
Step (6)：The electric current i that step (4) obtainssa, isb, iscBecome with the lock phase angle theta that step (5) obtains by abc/dq Power network current active component actual value i is tried to achieve after changingsdWith reactive component actual value isq。
Step (7)：The current on line side direct current active component reference value that step (3) obtainsStep (6) is subtracted through subtracter The power network current active component actual value i of acquisitionsdObtain current on line side direct current active component margin of error Δ isd。
Step (8)：Current on line side direct current active component margin of error Δ isdIt is active by obtaining line voltage after PI controllers Component reference value
Step (9)：Given power network current reactive component reference valueSubtract step (6) acquisition power network current without Work(component actual value isqObtain current on line side direct current reactive power error amount Δ isq。
Step (10)：Current on line side direct current reactive power error amount Δ isqBy obtaining line voltage reactive component after PI controllers Reference value
Step (11)：The line voltage active component reference value that step (8) obtainsWith the power network obtained with step (10) Voltage power-less component reference valueThree-phase modulations voltage is obtained after dq/abc is converted
Step (12)：Detect rectification stage items power Pa, Pb, Pc。
Step (13)：According to formulaTry to achieve mean power Pav。
Step (14)：The every power P obtained with step (12)a, Pb, PcDifference divided by step (13) averaging of income power Pav, try to achieve each Power Correction Factor ra, rb, rc。
Step (15)：The three-phase modulations voltage that step (11) is tried to achieveEach tried to achieve with step (14) Power Correction Factor ra, rb, rcBring formula into In try to achieve voltage amendment operand V0。
Step (16)：The three-phase modulations voltage that step (11) is obtainedStep (15) acquisition is individually subtracted Voltage amendment operand V0Try to achieve the modulated signal of every phase
Step (17):As shown in figure (5), by rectification stage rated voltageEach H bridges submodule virtual voltage is individually subtractedThe obtained margin of error obtains DC voltage static difference compensation rate v after PI controllerski。
Step (18)：The DC voltage static difference that step (17) acquisition is individually subtracted with unit feed-forward voltage coefficient 1 compensates Measure vki, try to achieve each every grade H bridge submodules voltage correction factor rki。
Step (19)：The modulated signal for every phase that step (16) is obtainedStep (18) institute is multiplied by respectively Each the every grade H bridge submodules voltage correction factor r obtainedkiTry to achieve the drive signal of each switching tube
By 19 above-mentioned steps, drive signal of the rectifier bridge in gainedEffect is lower to work, and balance modules are defeated Go out voltage, complete the transformer rectification stage voltage output function.
(2) energy storage stage is separated
The discharge and recharge of scattered energy storage stage control energy-storage battery.The main network operation situation detected according to detection means, energy storage Battery, which is divided into, to be filled a little and discharge process.Under main power network nominal situation, energy-storage battery is charged, until quantity of electric charge percentage SoC reaches rated value, into poised state；Under poised state, the energy-storage battery quantity of electric charge is flat in one charging-discharging cycle of control Weighing apparatus；When main power network is when under short time voltage is interrupted or depth is fallen, control energy-storage battery electric discharge, maintenance electric power electric transformer has Energy needed for work(power output.It is independently accessed because energy-storage battery is scattered in electric power electric transformer, each energy-storage battery fills Discharge process can be with independent control.Whole charge control is realized by a quantity of electric charge outer shroud and a power inner ring；Entirely Control of discharge is realized by a power outer shroud and a quantity of electric charge inner ring；
Scheme energy-storage battery discharge and recharge example shown in (6) to be switched by a switching, two adders, two subtracters, two Proportional controller, two integrator compositions.Specific control process is as follows：
Step (1)：Network operation situation is detected, network operation situation is divided into nominal situation and damage.It is improper Situation refers to electric line voltage short interruptions or voltage depth is fallen.
Step (2)：As step (1) detects, network operation is normal, then switching switch is switched to charge mode.Power network is to electric power storage Pond is charged, and is charged to required rated value.
Step (3)：Fall as step (1) detects line voltage short interruptions or voltage depth, then switch switch and be switched to Charge mode.Energy storage battery discharges, and maintains the transformer rated output power.
Step (2) described charge control, detailed process are：
①：Energy-storage battery charging charge reference valueEnergy-storage battery electric charge actual charge value SoC is subtracted through subtracterki Draw energy-storage battery charge error component Δ SoCki。
②：Energy-storage battery charge error component Δ SoCkiThe power back-off margin of error is drawn through proportional controller
③：The power back-off margin of errorWith charge powerIt is superimposed after integrated device and just obtains the actual electric charge of energy-storage battery Value SoCki。
By above-mentioned quantity of electric charge outer shroud and a power inner ring double-closed-loop control, energy-storage battery is charged to required specified Value.
Step (3) described control of discharge, detailed process are：
①：Power needed for calculating electric power electric transformer, obtains power command value
②：Electric power electric transformer actual power value is subtracted through subtracterDraw the discharge power margin of error
③：The discharge power margin of errorPassing ratio controller draws energy-storage battery charge compensation margin of error Δ SoCki
④：ΔSoCkiWith energy-storage battery electric charge SoCkiAfter superposition electric power electric transformer actual power is obtained through integrator Value
Pass through above-mentioned power outer shroud and quantity of electric charge inner ring double-closed-loop control, battery discharging.Electric power electric transformer obtains Required rated output power.
Above-mentioned SoC is electric charge percentage, and it characterizes the state of charge of energy-storage battery,For the specified electricity of energy-storage battery Lotus amount.
(3) isolation level
DHB samples the output current shown in obtained Fig. 7Instructed with output-current ratingCompare and draw electricity Stream error signal.Current error signal is sent into current controller, and current controller can dynamically adjust current error signal, until Error signal is 0 during stable state.The dutycycle D of current controller outputkiJust the on high-tension side switching tube driving letters of DHB are obtained after modulated Number SP, the drive signal S of low pressure side pipeSObtained by phase shift.Control block diagram is as shown in Figure 7.By changing phase shifting angle φkiIt is adjustable Output voltage is saved, transformer both sides switching tube phase shift schematic diagram is as shown in Figure 8.
The control circuit example shown in (7) is schemed by a subtracter, a current controller, a modulator composition.Tool Body implementation steps are：
Step (1) .DHB output currentsInstructed with output-current ratingCurrent error signal Δ I is obtained through subtracter0
Step (2) current error signals obtain duty cycle signals D through current controllerki
Step (3) duty cycle signals DkiIt is modulated to draw the on high-tension side switching tube drive signal S of DHBP
The on high-tension side switching tube drive signal S of step (4) .DHBPBy phase shift θkiDraw the drive signal S of low pressure side pipeS
The switching signal S that step (5) is drawnPAnd SSDrive DHB switching tube work
(4)：Output stage
The specific control method of output stage double-closed-loop control is：Convert to obtain dq DC components by abc/dq, sat in dq DC component is controlled with PI in mark, it is possible to achieve floating.But coupling amount (such as electric current is introduced in dq coordinatesExcept by voltage control quantity ud、uqOutside influenceing, also by the coupled voltages of inductanceAnd output voltageInfluence) need decouple eliminate their influence.Current inner loop after decoupling, outer voltage governing equation such as formula (3) Shown, control block diagram is as schemed shown in (9).
The control example shown in (9) is schemed by 6 subtracters, 2 addition and subtraction blenders, 4 multipliers, 4 PI controllers Composition.Specific implementation step is：
Step (1)：Output voltage DC component reference instruction valueWith output voltage DC component actual valueThrough subtraction Device draws voltage error signal
Step (2)：Voltage error signalCurrent signal is drawn by PI controllers
Step (3)：Output voltage actual valueIt is multiplied by ωbCfDraw couple current
Step (4)：By load current DC componentSubtract the current signal obtained by step (2)Obtained by step (3) Couple currentDraw electric current loop reference instruction value
Step (5)：By electric current loop reference instruction value obtained by step (4)With output current DC component actual valueThrough subtracting Musical instruments used in a Buddhist or Taoist mass draws current error signal
Step (6)：Current error signalVoltage signal is drawn by PI controllers
Step (7)：Output current actual valueIt is multiplied by ωbLmDraw coupled voltages
Step (8)：By output voltage DC component actual valueSubtract the voltage signal obtained by step (6)And step (7) coupled voltages obtained byDraw modulation voltage ud
Step (9)：Output voltage DC component reference instruction valueWith output voltage DC component actual valueThrough subtraction Device draws voltage error signal
Step (10)：Voltage error signalCurrent signal is drawn by PI controllers
Step (11)：Output voltage actual valueIt is multiplied by ωbCfDraw couple current
Step (12)：By load current DC componentSubtract the current signal obtained by step (10)With step (11) The coupled voltages of gainedDraw electric current loop reference instruction value
Step (13)：By electric current loop reference instruction value obtained by step (12)With output current DC component actual value Current error signal is drawn through subtracter
Step (14)：Current error signalVoltage signal is drawn by PI controllers
Step (15)：Output current actual valueIt is multiplied by ωbLmDraw coupled voltages
Step (16)：By output voltage DC component actual valueSubtract the voltage signal obtained by step (14)And step Suddenly the coupled voltages obtained by (15)Draw modulation voltage uq
Step (17)：By modulation voltage u obtained by step (8)dWith step (16) gained modulation voltage uqBy dq/abc contravariant Drive signal, the pipe work of driving inverter switching device are produced after changing
Described LmFor inverter filtering inductance, CfFor inverter filtering electric capacity, ωbFor inverter output voltage angular frequency.

Claims (7)

  1. A kind of 1. electric power electric transformer of scattered energy storage, it is characterised in that：The electric power electric transformer includes power cell And output module, the power cell include H bridge modules, energy-storage module, isolation module；The input of the electric power electric transformer Each phase at end all accesses the input company of the input of H bridge modules, the output end of H bridge modules and corresponding energy-storage module Connect, the output end of energy-storage module connects with the input of corresponding isolation module；It is the H bridge modules, corresponding to H bridge modules Energy-storage module and isolation module corresponding with energy-storage module composition power cell；Each in electric power electric transformer is single-phase On all access n power cell and an output module, the input of the inputs of H bridge modules as power cell, power list The input of member is connected with power network, cascade Connection in phase, alternate Y-connection；The output end of isolation module is defeated for power cell Go out end, the output end of power cell is in parallel, is connected with the input of output module；All H bridge modules structures on each is single-phase Into this it is single-phase on cascade rectifier level, all energy-storage modules on each is single-phase form this it is single-phase on scattered energy storage stage, often One it is single-phase on all isolation modules form this it is single-phase on isolation level, output stage is made up of an output module；The storage Energy module includes an One Buck-Boost converter body, and filter inductance and battery, battery pass through filter inductance and Buck- Boost is connected；
    The rate-determining steps of the cascade rectifier level include as follows：
    Step S1：The virtual voltage of sampling cascade every grade of H bridge module of rectification stageK represents phase (k ∈ a, b, c), and i represents series (1~n of i ∈), asks for virtual voltage average value vdc；
    Step S2：Rectification stage is per step voltage nominal reference componentThe virtual voltage average value obtained by step S1 is subtracted through subtracter vdc, obtain voltage error component Δ vdc；
    Step S3：Voltage error component Δ vdcCurrent on line side direct current active component reference value is drawn after PI controllers
    Step S4：Calculate power network current active component actual value isdWith reactive component actual value isq；
    Step S5：The current on line side direct current active component reference value that step S3 is obtainedThe electricity obtained by step S4 is subtracted through subtracter Net active component of current actual value isdObtain current on line side direct current active component margin of error Δ isd；
    Step S6：Current on line side direct current active component margin of error Δ isdJoined by obtaining line voltage active component after PI controllers Examine value
    Step S7：Given power network current reactive component reference value The power network current reactive component for subtracting step S4 acquisitions is real Actual value isqObtain current on line side direct current reactive power error amount Δ isq；
    Step S8：Current on line side direct current reactive power error amount Δ isqBy obtaining line voltage reactive component reference value after PI controllers
    Step S9：The line voltage active component reference value that step S6 is obtainedThe line voltage reactive component obtained with step S8 Reference valueThree-phase modulations voltage is obtained after dq/abc is converted
    Step S10：Calculate voltage amendment operand V0；
    Step S11：The three-phase modulations voltage that step S9 is obtainedThe voltage amendment of step S10 acquisitions is individually subtracted Operand V0Try to achieve the modulated signal of every phase
    Step S12：Calculate and correct factor r per mutually every grade of H bridge submodules voltageki；
    Step S13：By the modulated signal of the step S11 every phases obtainedH bridge submodule voltages are multiplied by respectively to rectify Positive factor rkiTry to achieve the drive signal of each IGBT pipes
    The step S10 includes：
    Step S101：Detect each phase power P of rectification stagea, Pb, Pc；
    Step S102：According to formulaTry to achieve mean power Pav；
    Step S103：Each phase power P obtained with step S101a, Pb, PcDifference divided by step S102 averaging of income power Psav, ask Obtain per phase Power Correction Factor ra, rb, rc；
    Step S104：The three-phase modulations voltage that step S11 is tried to achieveThe every phase power school tried to achieve with step S103 Positive factor ra, rb, rcBring formula intoIn try to achieve Voltage amendment operand V0。
  2. A kind of 2. electric power electric transformer of scattered energy storage according to claim 1, it is characterised in that：Described scattered storage The discharge and recharge of control of Energy Level energy-storage battery, under main power network nominal situation, energy-storage battery is charged, until quantity of electric charge percentage SoC reaches rated value, into poised state；Under poised state, the energy-storage battery quantity of electric charge is flat in one charging-discharging cycle of control Weighing apparatus；Main power network is when short time voltage is interrupted or depth is fallen, control energy-storage battery electric discharge.
  3. A kind of 3. electric power electric transformer of scattered energy storage according to claim 1, it is characterised in that the step S4 bags Include：
    Step S41：Sample line voltage and obtain three-phase voltage value vsa, vsb, vsc, sampling power network current acquisition three-phase electricity flow valuve isa, isb, isc；
    Step S42：Step S41 is sampled into gained line voltage vsa, vsb, vscLock phase angle theta is obtained after synchronized lock phase module；
    Step S43：The electric current i that step S41 is obtainedsa, isb, iscThe lock phase angle theta obtained with step S42 is after abc/dq is converted Try to achieve power network current active component actual value isdWith reactive component actual value isq。
  4. A kind of 4. electric power electric transformer of scattered energy storage according to claim 1, it is characterised in that the step S12 Including：
    Step S121:By rectification stage voltagerating reference componentEach H bridges submodule virtual voltage is individually subtractedObtain The margin of error obtains DC voltage static difference compensation rate v after PI controllerski；
    Step S122：The DC voltage static difference compensation rate v of step S121 acquisitions is individually subtracted with unit feed-forward voltage coefficientki, Try to achieve every mutually every grade of H bridge submodules voltage correction factor rki。
  5. A kind of 5. control method of the electric power electric transformer of scattered energy storage according to claim 1, it is characterised in that energy storage The process of the discharge and recharge of battery comprises the following steps：
    Step (1)：Network operation situation is detected, network operation situation is divided into nominal situation and damage, abnormal condition Refer to line voltage short interruptions or voltage depth is fallen；
    Step (2)：As step (1) detects, network operation is normal, then switching switch is switched to charge mode；Power network fills to battery Electricity, and it is charged to required rated value；
    Step (3)：Fall as step (1) detects line voltage short interruptions or voltage depth, then switch switch and be switched to electric discharge Pattern, energy storage battery electric discharge, maintains the transformer rated output power；
    The charge mode of the step (2), comprises the following steps：
    ①：Energy-storage battery charging charge reference valueEnergy-storage battery electric charge actual charge value SoC is subtracted through subtracterkiDraw storage Can battery charge error component Δ SoCki；
    ②：Energy-storage battery charge error component Δ SoCkiThe power back-off margin of error is drawn through proportional controller
    ③：The power back-off margin of errorWith charge powerIt is superimposed after integrated device and just obtains energy-storage battery actual charge value SoCki；
    The discharge mode of the step (3), comprises the following steps：
    1. power needed for calculating electric power electric transformer, obtains power command value
    ②Electric power electric transformer actual power value is subtracted through subtracterDraw the discharge power margin of error
    3. the discharge power margin of errorPassing ratio controller draws energy-storage battery charge compensation margin of error Δ SoCki；
    ④ΔSoCkiWith energy-storage battery electric charge SoCkiAfter superposition electric power electric transformer actual power value is obtained through integrator
    Above-mentioned SoC is electric charge percentage, and it characterizes the state of charge of energy-storage battery.
  6. A kind of 6. control method of the electric power electric transformer of scattered energy storage according to claim 1, it is characterised in that every Comprise the following steps from class control process：
    Step (1) isolation level output currentsInstructed with output-current ratingCurrent error signal Δ I is obtained through subtracter0；
    Step (2) current error signals obtain duty cycle signals D through current controllerki；
    Step (3) duty cycle signals DkiIt is modulated to draw the on high-tension side switching tube drive signal S of isolation levelP；
    The on high-tension side switching tube drive signal S of step (4) isolation levelsPBy phase shift θkiDraw the drive signal S of low pressure side pipeS；
    Switching signal S obtained by step (5) steps (3) and step (4)PAnd SSDrive the switching tube work of isolation level.
  7. 7. the control method of the electric power electric transformer of a kind of scattered energy storage according to claim 1, it is characterised in that defeated Go out class control process to comprise the following steps：
    Step (1)：Output voltage DC component reference instruction valueWith output voltage DC component actual valueObtained through subtracter Go out voltage error signal
    Step (2)：Voltage error signalCurrent signal is drawn by PI controllers
    Step (3)：Output voltage actual valueIt is multiplied by ωbCfDraw couple current
    Step (4)：By load current DC componentSubtract the current signal obtained by step (2)With the coupling obtained by step (3) Electric currentDraw electric current loop reference instruction value
    Step (5)：By electric current loop reference instruction value obtained by step (4)With output current DC component actual valueThrough subtracter Draw current error signal
    Step (6)：Current error signalVoltage signal is drawn by PI controllers
    Step (7)：Output current actual valueIt is multiplied by ωbLmDraw coupled voltages
    Step (8)：By output voltage DC component actual valueSubtract the voltage signal obtained by step (6)With step (7) institute The coupled voltages obtainedDraw modulation voltage ud；
    Step (9)：Output voltage DC component reference instruction valueWith output voltage DC component actual valueObtained through subtracter Go out voltage error signal
    Step (10)：Voltage error signalCurrent signal is drawn by PI controllers
    Step (11)：Output voltage actual valueIt is multiplied by ωbCfDraw couple current
    Step (12)：By load current DC componentSubtract the current signal obtained by step (10)Obtained by step (11) Coupled voltagesDraw electric current loop reference instruction value
    Step (13)：By electric current loop reference instruction value obtained by step (12)With output current DC component actual valueThrough subtraction Device draws current error signal
    Step (14)：Current error signalVoltage signal is drawn by PI controllers
    Step (15)：Output current actual valueIt is multiplied by ωbLmDraw coupled voltages
    Step (16)：By output voltage DC component actual valueSubtract the voltage signal obtained by step (14)With step (15) The coupled voltages of gainedDraw modulation voltage uq；
    Step (17)：By modulation voltage u obtained by step (8)dWith step (16) gained modulation voltage uqAfter dq/abc inverse transformations Produce drive signal, the pipe work of driving inverter switching device；
    Described LmFor inverter filtering inductance, CfFor inverter filtering electric capacity, ωbFor inverter output voltage angular frequency.
CN201510303821.7A 2015-06-04 2015-06-04 A kind of electric power electric transformer and its control method of scattered energy storage Active CN104868762B (en)

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