CN204030617U - Mobile energy-accumulating power station energy storage power conversion system - Google Patents

Abstract

The utility model relates to a kind of mobile energy-accumulating power station energy storage power conversion system, comprises main circuit and controller circuitry, and described main circuit comprises and is connected in parallel on voltage source converter on DC bus and electric capacity, and pre-charge module is connected to the two ends of electric capacity; Described controller circuitry comprises analog-digital converter module, signal processing circuit, driving and power protecting circuit and controller; signal processing circuit gathers bus charging and discharging currents signal, battery voltage signal, inverter output current signal, system output current signal, mains voltage signal and DC voltage signal; analog to digital converter module is connected with electric capacity by insulation monitoring module; the AC of voltage source converter and DC side are respectively equipped with grid-connected switch and charge and discharge switch, and controller is by driving and power protecting circuit connection voltage source converter.

Description

Mobile energy-accumulating power station energy storage power conversion system

Technical field

The utility model relates to technical field of electrical automation control, relates to mobile energy-accumulating power station energy storage power conversion system in particular.

Background technology

Energy storage power conversion system PCS is the mutual critical component of battery energy storage carrier and electrical network, pass through PCS, energy-storage battery obtains energy or exports energy to AC network from AC network, in the discharged condition, direct current energy in battery pack carries out energy conversion by PCS, direct current energy is transformed to AC energy feedback grid, in charged state, PCS passes through energy conversion, AC energy is transformed to direct current energy, charge the battery, thus realize managing the charge/discharge of battery pack, net side and to gain merit the function such as frequency modulation and idle pressure regulation, islet operation, black starting-up.At present, high-power mobile energy storage technology is also in emerging developing stage, and the advantages such as its fast charging and discharging, efficient active reactive adjustment have a wide range of applications.The islet operation of powerful mobile energy storage technology from net seamless switching, system cloud gray model safety and suppress the technology such as high order harmonic component and its application to need the system further improving mobile energy storage.

Summary of the invention

For correlative technology field document and above the deficiencies in the prior art, in a large amount of existing literature research with for a long time on the basis of association area Development Practice, the utility model proposes " mobile energy-accumulating power station energy storage power conversion system ", overcome " the islet operation of powerful mobile energy storage technology in prior art, and from net seamless switching, system cloud gray model safety and suppress the technology such as high order harmonic component and its application to need the system further improving mobile energy storage " etc. technical barrier, " powerful fast charging and discharging is realized by " adopting the controller of DSP and FPGA " realization, good suppression high order harmonic component " beneficial effect.

For achieving the above object, the utility model is achieved through the following technical solutions: a kind of mobile energy-accumulating power station energy storage power conversion system, this system comprises main circuit and controller circuitry, described main circuit comprises and is connected in parallel on voltage source converter on DC bus and electric capacity, and pre-charge module is connected to the two ends of electric capacity; Described controller circuitry comprises analog-digital converter module, signal processing circuit, driving and power protecting circuit and controller; signal processing circuit gathers bus charging and discharging currents signal, battery voltage signal, inverter output current signal, system output current signal, mains voltage signal and DC voltage signal; analog to digital converter module is connected with electric capacity by insulation monitoring module, and the AC of voltage source converter and DC side are respectively equipped with grid-connected switch and charge and discharge switch.The DC bus termination of described main circuit enters storage battery, makes voltage source converter four quadrant running by changing the modulation ratio m of voltage source converter and merit angular difference δ, provides two-way controlled meritorious, idle, stable with the voltage of control system access point and frequency.The DC bus-bar voltage scope of described main circuit is from 590V to 800V.The maximum 170A of the DC side electric current of the DC bus of described main circuit.Described controller comprise DSP, FPGA and be connected to the analog signal sampling modulate circuit of FPGA, switching value optocoupler input interface circuit, switching value optocoupler output interface circuit, PWM optical fiber drives interface circuit and IPM fault optical fiber input interface circuit, FPGA by the data upload that gathers in DSP.Described DSP comprises real-time operation processing unit and communication control unit, real-time operation cell processing digital filtering, static coordinate conversion, rotating coordinate transformation, digital PLL algorithm, PI regulate and SVPWM generation Duty ratio control algorithm, and described communication control unit communicates with BMS with supervisory control system.Described controller sends beginning and the end that precharge switch control signal controls pre-charge process; Whether controller sends grid-connected switch controlling signal, control energy-storage system and be incorporated into the power networks; Controller sends charge and discharge switch control signal, controls beginning and the end of charge and discharge process.Described pre-charge module charges to DC bus capacitor, makes it to reach scheduled voltage, and to batteries charging.

The beneficial effect that the utility model possesses is: the utility model devises the energy-storage system of 100KW, powerful fast charging and discharging can be realized, well suppress high order harmonic component, it adopts the controller of DSP and FPGA can realize complex calculations and signal isolation, ensures system safety operation.

Accompanying drawing explanation

Fig. 1 is the pcs system structure of the utility model specific embodiment;

Fig. 2 is the controller hardware system of the utility model specific embodiment.

Embodiment

Contrast accompanying drawing below, by the description to embodiment, to embodiment of the present utility model as involved control system, mutual annexation, and implementation method, be described in further detail, have more complete, accurate and deep understanding to help those skilled in the art to inventive concept of the present utility model, technical scheme.

As shown in Figure 1, a kind of mobile energy-accumulating power station energy storage power conversion system, this system comprises main circuit and controller circuitry, and described main circuit comprises and is connected in parallel on voltage source converter on DC bus and electric capacity, and pre-charge module is connected to the two ends of electric capacity; Described controller circuitry comprises analog-digital converter module, signal processing circuit, driving and power protecting circuit and controller; signal processing circuit gathers bus charging and discharging currents signal, battery voltage signal, inverter output current signal, system output current signal, mains voltage signal and DC voltage signal; analog to digital converter module is connected with pre-charge module by insulation monitoring module, and the AC of voltage source converter and DC side are respectively equipped with grid-connected switch and charge and discharge switch.The DC bus termination of described main circuit enters storage battery, makes voltage source converter four quadrant running by changing the modulation ratio m of voltage source converter and merit angular difference δ, provides two-way controlled meritorious, idle, stable with the voltage of control system access point and frequency.The DC bus-bar voltage scope of described main circuit is from 590V to 800V.The maximum 170A of the DC side electric current of the DC bus of described main circuit.Described controller comprise DSP, FPGA and be connected to the analog signal sampling modulate circuit of FPGA, switching value optocoupler input interface circuit, switching value optocoupler output interface circuit, PWM optical fiber drives interface circuit and IPM fault optical fiber input interface circuit, FPGA by the data upload that gathers in DSP.Described DSP comprises real-time operation processing unit and communication control unit, real-time operation cell processing digital filtering, static coordinate conversion, rotating coordinate transformation, digital PLL algorithm, PI regulate and SVPWM generation Duty ratio control algorithm, and described communication control unit communicates with BMS with supervisory control system.Described controller sends beginning and the end that precharge switch control signal controls pre-charge process; Whether controller sends grid-connected switch controlling signal, control energy-storage system and be incorporated into the power networks; Controller sends charge and discharge switch control signal, controls beginning and the end of charge and discharge process.Described pre-charge module charges to DC bus capacitor, makes it to reach scheduled voltage, and to batteries charging.Controller should have PWM output function, thus controls turning on and off of power device, realizes the basic function of PCS energy hole.

PCS is by detecting amplitude and the phase place of AC voltage, regulate current amplitude and the phase place of injected system access point (PCC point), thus realize the two-way flow of energy between DC side and AC, namely can four quadrant running, realize two-way meritorious, the reactive power exchange between energy-storage units and electric power system, thus there is the performance of net side power factor controlling, energy two-way transmission.When PCS draws electric energy from electrical network, it runs on rectification operating state; When PCS is to electrical grid transmission electric energy, it runs on inversion operating state.

PCS controller carries out computing by CPU and realizes various controlling functions:

(1) precharge: need to carry out precharge during first use after Mobile energy storage system arrives destination, charged to DC bus capacitor by the pre-charge circuit of major loop on the one hand, make it to reach scheduled voltage, on the other hand to batteries charging, make it to meet application requirement.

(2) grid-connected charging controls: and under net state, PCS can realize the energy needed for the conveying of net side direction energy-storage system, and charging current, charge power are controlled, and harmonic content controls in rated range.

(3) grid-connected control of discharge: and net state under, PCS can realize energy-storage system to net side conveying needed for energy, charging current, charge power are controlled, and harmonic content controls in rated range.

(4) net side power factor controlling: and under net state, PCS can regulate net side power factor, and energy-storage system is discharged or absorbing reactive power.

(5) grid-connectedly net is left: PCS can make energy-storage system depart from electrical network with security and stability, is from net state by grid-connected state-transition.

(6) turn grid-connected from net: PCS can make energy-storage system access electrical network with security and stability, by changing into from net state and net state.

Major loop parameter of the present utility model is selected to comprise following aspect

1, maximum grid-connected current

Grid line voltage is the topological structure of 380V, single stage type, and PCS capacity is 100kW, and consider that power factor is the situation of 1, then under nominal case, ac-side current is:

$I_{\mathrm{SN}}=1\×{10}^5/(\sqrt{3}\×380)=151.93A$

Consider the situation of 120% overload, then upper current limit is:

I _SNmax＝I _N×1.2＝182.32A

2, the function of net side filter and design

Mobile energy storage system should adopt LCL filter, needs the inductance value of design two inductance and the capacitance of an electric capacity.The major function that filter surveyed by net is filtering high order harmonic component, and filter inductance is larger, and filter effect is better, but along with inductance increase, the dynamic property of system can be deteriorated, and system cost and volume also can raise.When filter capacitor increases, filter effect can be strengthened, but system resonance frequencies can reduce, if resonance frequency is reduced to fundamental frequency, and the stability of meeting influential system.Further, increasing electric capacity can make LCL filter absorption more idle.The requirement of harmonic current value and total harmonic distortion coefficient (THD) will be met during design, especially good filtration result to be had to the harmonic wave that current transformer produces at switching frequency place, usually weigh the content of certain specific subharmonic in unsinusoidal periodic quantity than d with harmonic attenuation, the harmonic attenuation ratio of General Requirements current on line side is limited in less than 0.2.Under the prerequisite meeting above-mentioned designing requirement, used inductance, capacitance should be reduced as far as possible, thus cost-saving, reduction equipment volume, improve the dynamic property of system on the other hand.Above-mentioned design standard is followed in the design of LCL filter, usually adopts following distribution design method: (1) determines total inductance L _tspan: be improve the follow-up control of electric current and the response speed of system, inductance L _tvalue the smaller the better.But the value of inductance is larger, the filter effect of filter can be better.Therefore, need to consider the suitable value of selection:

$\frac{U_{\mathrm{dc}}}{4\sqrt{3}{i}_{\mathrm{ripm}}{f}_{\mathrm{sw}}}\≤L_T\≤\frac{\sqrt{\frac{{U_{\mathrm{de}}}^2}{3}-E_m^2}}{\mathrm{\ω}{I}_{\mathrm{sm}}}$

Wherein, i _ripmbe harmonic current peak value, be generally 15%, E of fundamental current peak value _mfor electrical network phase voltage peak value; I _smfor electrical network phase current peak value; f _swfor the switching frequency of rectifier; ω is the angular frequency of line voltage.

(2) electric capacity C is determined _fspan: too low in order to avoid rectifier power factor, the First Harmonic Reactive Power that general filter capacitor absorbs can not be greater than 5% of system nominal active power:

$C_f<5\%\frac{P_n}{3\&CenterDot;2\mathrm{\&pi;f}\&CenterDot;E^2}$

Wherein, P _nfor the active power of Systemic absorption under rated condition; F is the frequency of line voltage; E is the effective value of electrical network phase voltage.

(3) each parameter of filter is determined than d according to harmonic attenuation: make r=LS/L, the value of setting d, filter capacitor C _fand inductance L _t, judge that following quadratic equation is with or without normal solution:

${\mathrm{dr}}^2+(2d+1-{\mathrm{d\&omega;}}_{\mathrm{sw}}^2{L}_T{C}_f)r+d+1=0$

If equation does not have normal solution to change d, C _f, T _lvalue, until equation has normal solution.Wherein, L is current transformer side inductance value, L _sfor net side inductance value.

(4) judge whether resonance frequency meets the demands, if do not met, returning the 3rd step and redesigning.For avoiding resonance to occur near major harmonic frequency, resonance frequency need meet:

10f _n≤ f _res≤ 0.5f _swwherein

For the PCS of this project 100kW, design filtering total inductance is 0.1pu, and so, filtering total inductance is:

$L_T=0.1\mathrm{pu}/(\sqrt{3}\&times;\mathrm{\&omega;}\&times;I_{\mathrm{SN}})=0.1\&times;380/(\sqrt{3}\&times;2\mathrm{\&pi;}\&times;50\&times;151.93)=0.46\mathrm{mH}$

Design L=150 μ H, L _sit is 2kHz that=300 μ H. get resonance frequency, then capacitor design is:

$C_f=\frac{L+L_s}{{\mathrm{LL}}_s{\left(2\mathrm{\&pi;}{f}_{\mathrm{res}}\right)}^2}=63.3\mathrm{\&mu;F}$

3, DC side battery voltage range set

Battery modules for single stage type networking plan designs, and first needs to provide the DC voltage range that current transformer can adapt to.According to the regulation in GB GB/T12325-2003 " quality of power supply admissible deviation of supply volt-age ", for 10 kilovolts and following three-phase power supply system, its voltage permissible variation is positive and negative 7%, the voltage ripple of power network scope allowed during energy storage PCS designs should match therewith, considers that system voltage ripple of power network scope is positive and negative 10% here.Because energy-accumulating power station all needs to work in total power scope in which kind of system-level application, therefore its DC bus-bar voltage minimum should lower than 590V.During access 380V utility grid, generally choose the IGBT pipe of 1200V voltage withstand class, consider the due to voltage spikes that in IGBT switching process, DC bus stray inductance causes, the DC bus operating voltage of the highest general permission work is generally below 800V, therefore determines that the DC bus-bar voltage scope that single stage type non-isolation type PCS can allow is from 590V to 800V here.

4, DC side maximum current

When adopting single stage type isolated form scheme, the DC bus-bar voltage minimum value that PCS can allow is 590V, and consider the situation of operating at full capacity, the maximum that can obtain DC side electric current is: I _dcmax=1 × 10 ⁵/ 590=170A.

As shown in Figure 2, be the hardware general frame of controller system.The hardware circuit design of control system mainly comprises: the design of analog signal sampling modulate circuit, the design of switching value optocoupler input interface circuit, the design of switching value optocoupler output interface circuit, PWM optical fiber drive the design of interface circuit and the design etc. of IPM fault optical fiber input interface circuit.The real-time operation process of DSP primary responsibility and Communication Control, real-time operation process relates to digital filtering, static coordinate conversion, rotating coordinate transformation, digital PLL algorithm, PI regulate and SVPWM generates the realization of the control algolithms such as duty ratio, and Communication Control relates to and communicating with master control, BMS etc.FPGA by gather data upload in DSP, for the process of control algolithm; DSP performs control algolithm, and passes in FPGA under generating duty cycle information, compares export PWM control impuls with the triangular carrier in FPGA.Control system needs the signal detecting and export mainly can be divided into following a few class: the analog signal that (1) needs detect has: PCS AC three-phase current, PCC place three-phase phase voltage, DC bus-bar voltage, DC bus current; (2) digital signal detected is needed to have: various status switch amount signal (contactor closure signal, breaker closing signal), various error protection signal (the IPM fault-signal of fuse hot stall signal, reactor hot stall signal, current transformer temperature fault signal, current transformer) etc.; (3) control signal exported is generally on-off model, mainly contains: the relay control signal (AC contactless contactor, DC side killer switch, precharge switch) etc. of the pwm pulse drive singal of current transformer, various switch.The forceful electric power signal of high voltage, big current is generally all belonged to from current transformer signal out, the level of its digital output modul and status signal is generally also at least DC24V, and enter controller or be generally weak electric signal from the signal that controller exports, therefore need to design current transformer to the interface circuit of controller, current transformer high voltage out, big current signal are converted to low-voltage, the small area analysis signal of applicable controller.In field of power electronics, forceful electric power to the interface circuit of light current except high voltage signal will be completed to except the translation function of low voltage signal, also need to realize the isolation electrically, namely forceful electric power and light current realize the thorough isolation electrically, to improve the antijamming capability of system.The isolation of analog signal generally all adopts Hall element, instrument transformer or linear optical coupling to realize; The isolation of on-off model generally all adopts optocoupler to realize isolation; The isolation of pwm signal can adopt high speed photo coupling to isolate, and also can adopt Fiber isolation.

Professional can also recognize further, in conjunction with the execution step that embodiment disclosed herein describes, can realize with electronic hardware, computer software or the combination of the two, these functions perform with hardware or software mode actually, depend on application-specific and the design constraint of technical scheme.Professional and technical personnel can use distinct methods to realize described function to each specifically should being used for, but this realization should not thought and exceeds scope of the present utility model.The utility model is not limited to above-mentioned specific embodiment; do not departing under the utility model spirit and real situation thereof; those of ordinary skill in the art can make various corresponding change and distortion according to the utility model; these are tackled amendment that the utility model carries out mutually or equivalently to replace, and it all should be encompassed in the middle of the scope of claim of the present utility model protection.

Claims (8)

1. a mobile energy-accumulating power station energy storage power conversion system, is characterized in that: this system comprises main circuit and controller circuitry, and described main circuit comprises and is connected in parallel on voltage source converter on DC bus and electric capacity, and pre-charge module is connected to the two ends of electric capacity; Described controller circuitry comprises analog-digital converter module, signal processing circuit, driving and power protecting circuit and controller; signal processing circuit gathers bus charging and discharging currents signal, battery voltage signal, inverter output current signal, system output current signal, mains voltage signal and DC voltage signal; analog to digital converter module is connected with electric capacity by insulation monitoring module; the AC of voltage source converter and DC side are respectively equipped with grid-connected switch and charge and discharge switch, and controller is by driving and power protecting circuit connection voltage source converter.

2. energy power conversion system according to claim 1, it is characterized in that: the DC bus termination of described main circuit enters storage battery, voltage source converter four quadrant running is made by the modulation ratio m and merit angular difference δ that change voltage source converter, there is provided two-way controlled meritorious, idle, stable with the voltage of control system access point and frequency.

3. energy power conversion system according to claim 2, is characterized in that: the DC bus-bar voltage scope of described main circuit is from 590V to 800V.

4. energy power conversion system according to claim 2, is characterized in that: the maximum 170A of the DC side electric current of the DC bus of described main circuit.

5. energy power conversion system according to claim 1, it is characterized in that: described controller comprise DSP, FPGA and be connected to the analog signal sampling modulate circuit of FPGA, switching value optocoupler input interface circuit, switching value optocoupler output interface circuit, PWM optical fiber drives interface circuit and IPM fault optical fiber input interface circuit, FPGA by the data upload that gathers in DSP.

6. energy power conversion system according to claim 5, it is characterized in that: described DSP comprises real-time operation processing unit and communication control unit, real-time operation cell processing digital filtering, static coordinate conversion, rotating coordinate transformation, digital PLL algorithm, PI regulate and SVPWM generation Duty ratio control algorithm, and described communication control unit communicates with BMS with supervisory control system.

7. energy power conversion system according to claim 1 any one, is characterized in that: described controller sends beginning and the end that precharge switch control signal controls pre-charge process; Whether controller sends grid-connected switch controlling signal, control energy-storage system and be incorporated into the power networks; Controller sends charge and discharge switch control signal, controls beginning and the end of charge and discharge process.

8. energy power conversion system according to claim 1, is characterized in that: described pre-charge module is to DC bus capacitor and batteries charging.