CN102983563A - Coordination control method for common direct current bus mixing energy storage systems - Google Patents

Abstract

The invention provides a coordination control method for common direct current bus mixing energy storage systems. The method includes the steps of building topological structures of the mixing energy storage systems, coordinately controlling different types of the energy storage systems by means of a direct current (DC) / DC converter control mode normalization model, and coordinately controlling the energy storage systems in the same type and with different capacity. According to the coordination control method for the common direct current bus mixing energy storage systems, by means of coordinate control for a lithium battery energy storage system and a super capacitor energy storage system, reasonable utilization of the different types of energy storage systems is realized, and therefore, the response speed of the systems is improved, service life of the energy-type energy storage systems is prolonged, and technical performance and economical performance of the whole system are improved.

Description

A kind of control method for coordinating of common DC bus mixed energy storage system

Technical field

The invention belongs to operation and the control technology field of little electrical network, be specifically related to a kind of control method for coordinating of common DC bus mixed energy storage system.

Background technology

In the Distributed Renewable Energy Power System with energy-storage system, usually select storage battery as energy-storage travelling wave tube, but storage battery as the energy-storage travelling wave tube of energy type, have that power density is low, charge and discharge cycles times influence its useful life etc. shortcoming.Super capacitor is as the power-type energy-storage travelling wave tube, because the advantages such as its power density is high, have extended cycle life, efficiency for charge-discharge height, Maintenance free, just receive increasing concern, but because its energy density is lower, also be difficult to realize at present jumbo electric power energy storage.Storage battery and ultracapacitor mixed use, be applied to renewable energy system, make the large and super capacitor power density of storage battery energy density greatly, the characteristics that have extended cycle life combine, and can greatly promote technical performance and the economic performance of whole system.

At present, existing researcher is applied to electric automobile, compact power and renewable energy source domain for hybrid energy-storing and did some researchs, has mainly proposed the structure of following several common DC bus hybrid energy-storings:

(1) storage battery and ultracapacitor are directly in parallel.Storage battery, the direct parallel connection of ultracapacitor is the simplest a kind of hybrid energy-storing structure, adopt this structure, can be when fluctuation occurs in load, significantly reduce the maximum output current of storage battery during the fluctuation of load, improve the maximum power output ability of mixed energy storage system, but in this structure, because the terminal voltage of batteries is forced to equate with the terminal voltage of bank of super capacitors, cause the capacity of super capacitor utilance low, connection in series-parallel compound mode to bank of super capacitors in design requires also comparatively strict, and the course of work of storage battery can not be set flexibly, can not realize the efficient utilization of dissimilar energy storage devices.

(2) storage battery is in parallel with super capacitor by the DC/DC power inverter.Storage battery is in parallel with super capacitor by the DC/C converter, by the appropriate design to the power inverter control strategy, can realize the charge and discharge process of batteries is carried out flexible management, the advantage of better performance ultracapacitor, improve the performance of hybrid accumulator, prolong the useful life of storage battery.But, super capacitor is directly hung on the dc bus, ultracapacitor is in charge and discharge process, and terminal voltage can change along with the variation of energy storage capacity, and the change in voltage amplitude is larger, and DC bus-bar voltage is unstable.

(3) ultracapacitor is in parallel with storage battery by the DC/C converter.In order to obtain stable DC bus-bar voltage, there is document to propose ultracapacitor by the DC/DC converter hybrid energy-storing structure in parallel with batteries, although during power fluctuation, DC bus-bar voltage is comparatively stable, but adopt this structure, the flexible management of batteries input and output energy can not be realized equally, the effect of all kinds energy storage device can not be given full play to.

Control for the coordination between same type, the different capabilities energy storage device, mainly utilize at present communication system between each energy-storage module, to carry out sharing control, but between the voltage-controlled a plurality of DC/DC control modules of employing, adopt communication to carry out sharing control, exist communication context to be subjected to the restriction in geographical position, and the reliability of system and the lower shortcoming of redundancy; At present, to less without the control of the coordination between the DC/DC converter of the multivoltage control model of order wire research.

Summary of the invention

In order to overcome above-mentioned the deficiencies in the prior art, the invention provides a kind of control method for coordinating of common DC bus mixed energy storage system, by lithium battery energy storage battery system and super capacitor energy-storage system coordination are controlled, realize the reasonable utilization of dissimilar energy-storage systems, thereby improve the response speed of system, prolong the useful life of energy type energy storage, improve technology and the economic performance of whole system.

In order to realize the foregoing invention purpose, the present invention takes following technical scheme:

A kind of control method for coordinating of common DC bus mixed energy storage system is provided, said method comprising the steps of:

Step 1: the topological structure of setting up described mixed energy storage system;

Step 2: coordinate the dissimilar energy-storage systems of control by DC/DC convertor controls pattern normalization model;

Step 3: the coordination control of same kind, different capabilities energy-storage system.

In the described step 1, lithium battery energy storage battery system and super capacitor energy-storage system are in parallel with dc bus by DC/C converter A and DC/DC converter B respectively, consist of the topological structure of mixed energy storage system.

In the described step 2, the DC/DC converter comprises DC/DC converter A and DC/DC converter B, the control model of DC/DC converter comprises voltage mode control, constant current control model and permanent power control mode, determine above-mentioned control model by outer Voltage loop control, the control of intermediate current ring and the control of internal layer power ring respectively, the constant current control model comprises constant current charge control model and constant current discharge control model.

In the described voltage mode control, the busbar voltage reference value is got V _DCN, then have

ΔV _DC＝V _DCN-V _DC （1）

$k=\frac{{\mathrm{\ΔV}}_{\mathrm{DC}\_\max }}{I_{\mathrm{dcN}}}---\left(2\right)$

I′ _ref＝k·ΔV _DC （3）

In the formula: V _DCNThe rated voltage runtime value of dc bus in the-voltage mode control;

Δ V _{DC_max}The maximum deflection difference value that DC bus-bar voltage allows;

I _DcNThe current rating of-energy-storage system;

I ' _RefThe reference value of-energy-storage system the output current that obtains through the overvoltage droop control;

The limits value of current limit link and power limiting link is all determined according to the ruuning situation of DC/DC converter.

In the described constant current control model, the busbar voltage reference value is got U _{Ref_ab}, current limit link current limit is got the charging and discharging currents value of predefined super capacitor; Power limiting link power limit is determined according to the ruuning situation of DC/DC converter.

In the described permanent power control mode, the busbar voltage reference value is got U _{Ref_ab}, current limit link current limit is determined according to the ruuning situation of DC/DC converter; Power limiting link power limit is got the reference power value of the lithium battery energy storage battery system of tuning controller calculating.

In the described DC/DC convertor controls pattern normalization model, the difference of the reference value of busbar voltage and its measured value is through droop control, pass through again the current limit link, obtain the reference value of energy-storage system output current, the difference of energy-storage system output current reference value and its output current measured value is regulated through PI, and then by the power limiting link, obtain the reference value of energy-storage system power output, as the switch triggering signal of DC/DC converter; Described energy-storage system comprises lithium battery energy storage battery system and super capacitor energy-storage system.

Described step 2 may further comprise the steps:

Step 2-1: tuning controller Real-Time Monitoring DC bus-bar voltage, the terminal voltage of super capacitor is determined the control model of DC/DC converter A and DC/DC converter B according to the survey data;

Step 2-2: the power shortage P that calculates described energy-storage system _s, P _s=P _l-P _r, and extract P _sIn low frequency component P _{B_ref}, described P _{B_ref}Be the value and power reference of permanent power control mode lithium battery energy storage battery system, P _lBe the load power of distributed power source, P _rPower output for intermittent renewable energy system;

Step 2-3: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _Min＜U _Uc＜U _MaxThe time, DC/DC converter A works in permanent power control mode, and DC/C converter B works in voltage mode control;

Step 2-4: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _Uc＜U _MinThe time, DC/DC converter A works in voltage mode control, and DC/DC converter B works in the constant current charge control model;

Step 2-5: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _UcU _MaxThe time, the DC/DC converter A of control lithium battery system works in voltage mode control, and DC/DC converter B works in the constant current discharge control model;

Wherein, U _MinAnd U _MaxBe respectively the smallest end voltage of super capacitor permission and the maximum terminal voltage that super capacitor allows.

Described step 3 may further comprise the steps:

Step 3-1: the coordination control between the DC/DC converter of voltage mode control;

When the DC/DC converter all worked in voltage mode control, the DC/DC converter all adopted voltage droop control mode, according to the fluctuation of dc bus power difference, automatically regulated self discharging and recharging power, realized DC bus-bar voltage stable operation;

This moment, the sagging coefficient of every DC/DC converter was decided according to himself capacity:

Because

Then have

Wherein, k _nAnd k _mBe respectively the sagging coefficient of n platform and m platform DC/DC converter, S _mAnd S _nBe respectively the capacity of n and m energy-storage system;

Step 3-2: the coordination control between the DC/DC converter of permanent power control mode;

When the DC/DC converter of a plurality of permanent power control modes moved simultaneously, the power instruction that tuning controller is assigned was P _{B_ref}/ N, thus realize power-sharing control between the DC/DC converter of a plurality of permanent power control modes, and wherein, N is the number of units that works in the DC/DC converter of permanent power control mode.

Compared with prior art, beneficial effect of the present invention is:

1. the present invention can be applicable to the operation control of mixed energy storage system, can the optimum management lithium battery and the charge and discharge process of super capacitor, improve the course of work of lithium battery, reduce its charge and discharge cycles number of times and maximum depth of discharge, prolong the useful life of whole energy-storage system;

2. can be applicable to comprise operation and the control of the DC power-supply system of renewable energy power generation and energy-storage system, can the stable DC busbar voltage, keep the Systems balanth operation;

3. can be applicable to operation and the control of DC micro-electric net, realize the load power according to the equal subsystem of its capacity of the energy-storage system of different capabilities.

Description of drawings

Fig. 1 is common DC bus mixed energy storage system topology diagram;

Fig. 2 is DC/DC convertor controls pattern normalization model schematic diagram;

Fig. 3 is three kinds of operational mode schematic diagrames of DC/DC converter;

Fig. 4 is DC/C converter voltage control principle drawing.

Embodiment

Below in conjunction with accompanying drawing the present invention is described in further detail.

A kind of control method for coordinating of common DC bus mixed energy storage system is provided, said method comprising the steps of:

Step 1: the topological structure of setting up described mixed energy storage system;

Step 2: coordinate the dissimilar energy-storage systems of control by DC/DC convertor controls pattern normalization model;

Step 3: the coordination control of same kind, different capabilities energy-storage system.

Such as Fig. 1, in the described step 1, lithium battery energy storage battery system and super capacitor energy-storage system are in parallel with dc bus by DC/DC converter A and DC/DC converter B respectively, consist of the topological structure of mixed energy storage system.

Such as Fig. 2-Fig. 4, the DC/DC converter comprises DC/DC converter A and DC/DC converter B, the control model of DC/DC converter comprises voltage mode control (CV pattern), constant current control model (CC pattern) and permanent power control mode (CP pattern), determine above-mentioned control model by outer Voltage loop control, the control of intermediate current ring and the control of internal layer power ring respectively, the constant current control model comprises constant current charge control model and constant current discharge control model.

In the described voltage mode control, the busbar voltage reference value is got V _DCN, then have

ΔV _DC＝V _DCN-V _DC （1）

$k=\frac{{\mathrm{\ΔV}}_{\mathrm{DC}\_\max }}{I_{\mathrm{dcN}}}---\left(2\right)$

I′ _ref＝k·ΔV _DC （3）

In the formula: V _DCNThe rated voltage runtime value of dc bus in the-voltage mode control;

Δ V _{DC_max}The maximum deflection difference value that-DC bus-bar voltage allows;

I _DcNThe current rating of energy-storage system;

I ' _RefThe reference value of-energy-storage system the output current that obtains through the overvoltage droop control;

The limits value of current limit link and power limiting link is all determined according to the ruuning situation of DC/DC converter.

In the described constant current control model, the busbar voltage reference value is got U _{Ref_ab}, the specified runtime value that its choosing value should depart from dc bus is larger, in order to the mask voltage control ring; Current limit link current limit is got the charging and discharging currents value of predefined super capacitor; Power limiting link power limit is determined according to the ruuning situation of DC/DC converter.

In the described permanent power control mode, the busbar voltage reference value is got U _{Ref_ab}, the specified runtime value that its choosing value should depart from dc bus is larger, in order to the mask voltage control ring; Current limit link current limit is determined according to the ruuning situation of DC/DC converter; Power limiting link power limit is got the reference power value of the lithium battery energy storage battery system of tuning controller calculating.

In the described DC/DC convertor controls pattern normalization model, the reference value V of busbar voltage _DCNWith its measured value V _DCDifference Δ V _DCObtain I ' through droop control _Ref, I ' _RefPass through again the current limit link, obtain the reference value I of energy-storage system output current _Ref, energy-storage system output current reference value I _RefWith its output current measured value I _DcDifference regulate through PI and obtain P ' _Ref, P ' _RefBy the power limiting link, obtain the reference value P of energy-storage system power output _Ref, as the switch triggering signal of DC/DC converter; Described energy-storage system comprises lithium battery energy storage battery system and super capacitor energy-storage system.

Described step 2 may further comprise the steps:

Step 2-1: tuning controller Real-Time Monitoring DC bus-bar voltage, the terminal voltage of super capacitor is determined the control model of DC/DC converter A and DC/DC converter B according to the survey data;

Step 2-2: the power shortage P that calculates described energy-storage system _s, P _s=P _l-P _r, and extract P _sIn low frequency component P _{B_ref}, described P _{B_ref}Be the value and power reference of permanent power control mode lithium battery energy storage battery system, P _lBe the load power of distributed power source, P _rPower output for intermittent renewable energy system;

Step 2-3: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _Min＜U _Uc＜U _MaxThe time, DC/DC converter A works in permanent power control mode, and DC/DC converter B works in voltage mode control;

Step 2-4: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _Uc＜U _MinThe time, DC/DC converter A works in voltage mode control, and DC/DC converter B works in the constant current charge control model;

Step 2-5: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _UcU _MaxThe time, the DC/DC converter A of control lithium battery system works in voltage mode control, and DC/DC converter B works in the constant current discharge control model;

Wherein, U _MinAnd U _MaxBe respectively the smallest end voltage of super capacitor permission and the maximum terminal voltage that super capacitor allows.

Described step 3 may further comprise the steps:

Step 3-1: the coordination control between the DC/C converter of voltage mode control;

When the DC/DC converter all worked in voltage mode control, the DC/DC converter all adopted voltage droop control mode, according to the fluctuation of dc bus power difference, automatically regulated self discharging and recharging power, realized DC bus-bar voltage stable operation;

This moment, the sagging coefficient of every DC/DC converter was decided according to himself capacity:

Because $k=\frac{{\mathrm{\ΔV}}_{\mathrm{DC}\_\max }}{I_{\mathrm{dcN}}},$ Then have

$\frac{k_n}{k_m}=\frac{S_m}{S_n}---\left(4\right)$

Wherein, k _nAnd k _mBe respectively the sagging coefficient of n platform and m platform DC/DC converter, S _mAnd S _nBe respectively the capacity of n and m energy-storage system;

Step 3-2: the coordination control between the DC/DC converter of permanent power control mode;

When the DC/DC converter of a plurality of permanent power control modes moved simultaneously, the power instruction that tuning controller is assigned was P _{B_ref}/ N, thus realize power-sharing control between the DC/DC converter of a plurality of permanent power control modes, and wherein, N is the number of units that works in the DC/DC converter of permanent power control mode.

Should be noted that at last: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment the present invention is had been described in detail, those of ordinary skill in the field are to be understood that: still can make amendment or be equal to replacement the specific embodiment of the present invention, and do not break away from any modification of spirit and scope of the invention or be equal to replacement, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (9)

1. the control method for coordinating of a common DC bus mixed energy storage system is characterized in that: said method comprising the steps of:

Step 1: the topological structure of setting up described mixed energy storage system;

Step 2: coordinate the dissimilar energy-storage systems of control by DC/DC convertor controls pattern normalization model;

Step 3: the coordination control of same kind, different capabilities energy-storage system.

2. the control method for coordinating of common DC bus mixed energy storage system according to claim 1, it is characterized in that: in the described step 1, lithium battery energy storage battery system and super capacitor energy-storage system are in parallel with dc bus by DC/DC converter A and DC/DC converter B respectively, consist of the topological structure of mixed energy storage system.

3. the control method for coordinating of common DC bus mixed energy storage system according to claim 1, it is characterized in that: in the described step 2, the DC/DC converter comprises DC/DC converter A and DC/DC converter B, the control model of DC/DC converter comprises voltage mode control, constant current control model and permanent power control mode, determine above-mentioned control model by outer Voltage loop control, the control of intermediate current ring and the control of internal layer power ring respectively, the constant current control model comprises constant current charge control model and constant current discharge control model.

4. the control method for coordinating of common DC bus mixed energy storage system according to claim 3, it is characterized in that: in the described voltage mode control, the busbar voltage reference value is got V _DCN, then have

ΔV _DC＝V _DCN-V _DC （1）

$k=\frac{{\mathrm{\ΔV}}_{\mathrm{DC}\_\max }}{I_{\mathrm{dcN}}}---\left(2\right)$

I′ _ref＝k·ΔV _DC （3）

In the formula: V _DCNThe rated voltage runtime value of dc bus in the-voltage mode control;

Δ V _{DC_max}The maximum deflection difference value that-DC bus-bar voltage allows;

I _DcNThe current rating of-energy-storage system;

I ' _RefThe reference value of-energy-storage system the output current that obtains through the overvoltage droop control;

The limits value of current limit link and power limiting link is all determined according to the ruuning situation of DC/C converter.

5. the control method for coordinating of common DC bus mixed energy storage system according to claim 3, it is characterized in that: in the described constant current control model, the busbar voltage reference value is got U _{Ref_ab}, current limit link current limit is got the charging and discharging currents value of predefined super capacitor; Power limiting link power limit is determined according to the ruuning situation of DC/DC converter.

6. the control method for coordinating of common DC bus mixed energy storage system according to claim 3, it is characterized in that: in the described permanent power control mode, the busbar voltage reference value is got U _{Ref_ab}, current limit link current limit is determined according to the ruuning situation of DC/DC converter; Power limiting link power limit is got the reference power value of the lithium battery energy storage battery system of tuning controller calculating.

7. the control method for coordinating of common DC bus mixed energy storage system according to claim 1, it is characterized in that: in the described DC/DC convertor controls pattern normalization model, the difference of the reference value of busbar voltage and its measured value is through droop control, pass through again the current limit link, obtain the reference value of energy-storage system output current, the difference of energy-storage system output current reference value and its output current measured value is regulated through PI, and then by the power limiting link, obtain the reference value of energy-storage system power output, as the switch triggering signal of DC/DC converter; Described energy-storage system comprises lithium battery energy storage battery system and super capacitor energy-storage system.

8. the control method for coordinating of common DC bus mixed energy storage system according to claim 1, it is characterized in that: described step 2 may further comprise the steps:

Step 2-1: tuning controller Real-Time Monitoring DC bus-bar voltage, the terminal voltage of super capacitor is determined the control model of DC/DC converter A and DC/DC converter B according to the survey data;

Step 2-2: the power shortage P that calculates described energy-storage system _s, P _s=P _l-P _r, and extract P _sIn low frequency component P _{B_ref}, described P _{B_ref}Be the value and power reference of permanent power control mode lithium battery energy storage battery system, P _lBe the load power of distributed power source, P _rPower output for intermittent renewable energy system;

Step 2-3: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _Min＜U _Uc＜U _MaxThe time, DC/DC converter A works in permanent power control mode, and DC/DC converter B works in voltage mode control;

Step 2-4: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _Uc＜U _MinThe time, DC/DC converter A works in voltage mode control, and DC/DC converter B works in the constant current charge control model;

Step 2-5: the terminal voltage U of super capacitor energy-storage system _UcSatisfy U _UcU _MaxThe time, the DC/DC converter A of control lithium battery system works in voltage mode control, and DC/DC converter B works in the constant current discharge control model;

Wherein, U _MinAnd U _MaxBe respectively the smallest end voltage of super capacitor permission and the maximum terminal voltage that super capacitor allows.

9. the control method for coordinating of common DC bus mixed energy storage system according to claim 1, it is characterized in that: described step 3 may further comprise the steps:

Step 3-1: the coordination control between the DC/C converter of voltage mode control;

When the DC/DC converter all worked in voltage mode control, the DC/DC converter all adopted voltage droop control mode, according to the fluctuation of dc bus power difference, automatically regulated self discharging and recharging power, realized DC bus-bar voltage stable operation;

This moment, the sagging coefficient of every DC/DC converter was decided according to himself capacity:

Because $k=\frac{{\mathrm{\ΔV}}_{\mathrm{DC}\_\max }}{I_{\mathrm{dcN}}},$ Then have

$\frac{k_n}{k_m}=\frac{S_m}{S_n}---\left(4\right)$

Wherein, k _nAnd k _mBe respectively the sagging coefficient of n platform and m platform DC/DC converter, S _mAnd S _nBe respectively the capacity of n and m energy-storage system;

Step 3-2: the coordination control between the DC/DC converter of permanent power control mode;

When the DC/DC converter of a plurality of permanent power control modes moved simultaneously, the power instruction that tuning controller is assigned was P _{B_ref}/ N, thus realize power-sharing control between the DC/DC converter of a plurality of permanent power control modes, and wherein, N is the number of units that works in the DC/DC converter of permanent power control mode.

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