Background technology
Along with country constantly promotes intelligent grid, microgrid, renewable new energy source and Development of Electric Vehicles etc., the energy storage technology supporting as its key technology has also been obtained fast development.Current common energy storage form can be divided into four classes: electrochemical energy storage, physics energy storage, Power Flow and phase-change accumulation energy.The energy storage modes such as wherein, physics energy storage, Power Flow and phase-change accumulation energy are applied because being subject to the restriction of the aspects such as technical merit, geographical environment, service conditions, up-front investment expense cannot realize temporarily large-scale development.Yet, along with electrochemical techniques constantly break through, have high efficiency energy storage capacity, good resistance to environment serviceability, excellent operation maintenance convenience and the relatively low electrochemical energy storage of up-front investment cost, obtaining the development of advancing by leaps and bounds and Demonstration Application widely.
In existing electrochemical energy storage Demonstration Application, conventionally extensive with lead-acid battery energy-storage system, lithium ion battery energy storage system and super capacitance cell energy-storage system etc.Wherein, using the energy-storage system of lead-acid battery as energy storage carrier, the maturation, high, the resistance to environment of stored energy capacitance of possessing skills is good, low-cost, recycling rate advantages of higher, but its weight energy ratio, volume energy are lower, cycle-index is less, and easily causes certain pollution in a large amount of manufactures or recycling process.Using the energy-storage system of lithium ion battery as energy storage carrier, have that high efficiency, high-energy-density, discharge voltage are stable, self discharge efficiency is low, memory-less effect and the advantage such as pollution-free, but because the lithium ion battery cost of raw material is higher, complex manufacturing technology, cause it expensive, in addition, lithium ion battery requires strictly, still can not realize large-scale application to discharging and recharging the aspects such as control and running environment.Using the energy-storage system of super capacitance cell as energy storage carrier, there is the features such as can reach up to ten thousand overlength cycle life, large current density power is strong, energy conversion efficiency is high, ultralow temperature operation characteristic is good, in electric power system, be used for level and smooth and quality of power supply branch power occasion of short time, powerful load, but its discharge time is shorter, specific energy is lower, cannot meet the requirement of electrical network being carried out to continued power.
Along with the exhaustion of the energy and the proposition of low-carbon (LC) life, renewable new forms of energy are developed rapidly and large-scale application, because the electricity generation systems such as photovoltaic, wind-force have stronger randomness, fluctuation, thereby largely, have affected the electrical network quality of power supply, in addition, in order to meet the fast and stable development of national economy, high power, jumbo load has also arrived extensive application, to a certain extent the electrical network quality of power supply has also been caused to certain influence, this just need to configure energy-storage system provides high arteries and veins to fill power with level and smooth photovoltaic generation, the power network fluctuation spike that output power of wind power generation and high power load application cause, the line voltage that effectively regulates generation of electricity by new energy and high-power equipment electricity consumption to cause, frequency meter phase place changes, equally also need energy-storage system to there is high power capacity power storage and releasability, thereby can be continuously mains supply to guarantee the normal operation of critical load.Yet from current existing energy storage technology practical application, lead-acid battery, lithium ion battery or super capacitor are as single energy-storage system application, as shown in Figure 1.Lead-acid battery energy-storage system mass-energy ratio, volume energy is lower and cycle-index is less, and a large amount of manufacture or recycling process in easily causing certain pollution; Lithium ion battery energy storage system is because adopting the cost of raw material higher, and complex manufacturing technology, causes it expensive, in addition, lithium ion battery to discharge and recharge control and the aspect such as running environment require strict, and overcharging, cross put or excess temperature situation under blasted, there is potential safety hazard; Super capacitance cell energy-storage system its discharge time is shorter, specific energy is lower, cannot meet the requirement of electrical network being carried out to continued power.Therefore, if to better meet electrical network to energy-storage system high power capacity, long-life, high energy storage in discharging, the arteries and veins requirement of filling the level and smooth and lower up-front investment cost of peak value etc., need energy-storage system both to possess the features such as high-specific-power, high cycle life, simultaneously can effectively reduce energy-storage system cost of investment, floor space, own wt etc. again, and the energy-storage system of applying single energy storage carrier all can not meet above-mentioned requirements.
Summary of the invention
Object of the present invention is exactly for addressing the above problem, a kind of mixed energy storage system of controlling in order based on energy is provided, it is good by comprehensive utilization lead-acid battery resistance to environment, cost is low and recoverable etc., lithium ion battery high efficiency, high-energy-density, discharge voltage are stable, service life cycle is more high and the advantage such as super capacitor high-specific-power, high cycle life realizes and having complementary advantages, and maximize favourable factors and minimize unfavourable ones.By background monitoring system, adopt Selective Control method, realize when peak power deviate or other abnormal conditions appear in electrical network, characteristic in conjunction with different energy storage carrier super capacitance cell in useful life group > lithium ion battery group > lead-acid battery groups, by super capacitance cell group → lithium ion battery group → lead-acid battery group energy, control in order utilization, thereby effectively reducing regenerative resource hits filling of electric power system, realization regulates electrical network peak load shifting, reduce electrical network peak value, improve power grid quality, fully guarantee the fail safe of whole network system operation, stability and reliability.
For achieving the above object, the present invention adopts following technical scheme:
A mixed energy storage system of controlling in order based on energy, it comprises three energy storage subsystems:
The first energy storage subsystem comprises that lead-acid battery group, first is from control module BMU, the first main control module BMS and the first Bidirectional variable-flow controller ACDC, lead-acid battery group is connected from control module BMU with first with the first Bidirectional variable-flow controller ACDC respectively, first is connected with the first main control module BMS from control module BMU, and the first main control module BMS is connected with background monitoring system;
The second energy storage subsystem comprises that lithium battery group, second is from control module BMU, the second main control module BMS and the second Bidirectional variable-flow controller ACDC, lithium battery group is connected from control module BMU with second with the second Bidirectional variable-flow controller ACDC respectively, second is connected with the second main control module BMS from control module BMU, and the second main control module BMS is connected with background monitoring system;
The 3rd energy storage subsystem comprises that super capacitance cell group, the 3rd is from control module CM U, the 3rd main control module CMS and the 3rd Bidirectional variable-flow controller ACDC, super capacitance cell group is connected from control module CM U with the 3rd with the 3rd Bidirectional variable-flow controller ACDC respectively, the 3rd is connected with the 3rd main control module CMS from control module CM U, and the 3rd main control module CMS is connected with background monitoring system;
Each is responsible for respectively lead-acid battery group, lithium ion battery group, voltage, electric current, monitoring temperature and the alarm and protection of super capacitance cell group, electric quantity balancing from control module, simultaneously by detection information by CAN bus, report main control module separately respectively; Each main control module is accepted the voltage, temperature, the current information that report, and record discharges and recharges number of times, estimates lead-acid battery group, lithium battery group and super capacitance cell group remaining capacity SOC simultaneously, assesses its health status SOH separately; Communicate by letter with background monitoring system in addition, complete upload lead-acid battery group, lithium battery group and super capacitance cell group abnormality alarming, constant data in time between daily record data, and the operational order that background monitoring system is issued passes to down respectively each main control module; Each main control module is communicated by letter with Bidirectional variable-flow controller ACDC separately respectively, complete and upload lead-acid battery group, lithium battery group and super capacitance cell group abnormality alarming, when lead-acid battery group or lithium ion battery group or super capacitance cell group generation overvoltage, under-voltage, overcurrent and excess temperature situation, ask corresponding Bidirectional variable-flow controller ACDC to realize and discharge and recharge power control, and pass to corresponding main control module under the operational order respectively each Bidirectional variable-flow controller ACDC being issued.
When being incorporated into the power networks and operation of power networks is normal, each main control module and from control module by the detection to each battery voltage, temperature, electric current, assess three energy storage subsystem remaining capacity SOC, and upload the data to Bidirectional variable-flow controller part, Bidirectional variable-flow controller is by judgement, as need charging, each battery pack is charged; If do not needed charging, press float charge voltage charging;
When electrical network is because of renewable generation of electricity by new energy or the initial t of load electricity consumption
0while constantly occurring that instantaneous power exceeds target power scope, by different energy storage subsystem SOC being detected to assessment and controlling, judgement is also controlled and is utilized principle in order by super capacitance cell group → lithium ion battery group → lead-acid battery group energy, whether decision discharges to electrical network, with effectively level and smooth electrical network, there is exceeding target power value range, realize " peak load shifting ".
When from network operation, first by each main control module with from control module, detect different battery pack remaining capacity SOC and report each Bidirectional variable-flow controller and background monitoring system, by background monitoring system, control each Bidirectional variable-flow controller, according to different battery pack state-of-charge SOC, whether judgement is also controlled in order and is utilized principle realization to power to network load by super capacitance cell group → lithium ion battery group → lead-acid battery group energy; Simultaneously; when super capacitance cell group is in electric discharge and after by the 3rd main control module CMS, the 3rd Bidirectional variable-flow controller ACDC protection; by the second energy storage subsystem, the first energy storage subsystem, charge to the 3rd energy storage subsystem successively; now; the 3rd Bidirectional variable-flow controller ACDC controls the 3rd energy storage subsystem power output, mainly by the second energy storage subsystem, the first energy storage subsystem, to network load, is powered successively thereafter.
While occurring that instantaneous power exceeds target power scope, concrete charge and discharge process is: first judge whether each battery pack SOC reaches set point, as do not reach, each Bidirectional variable-flow is controlled it each battery pack is protected, and forbids electric discharge; If reached, at t
0constantly, the second Bidirectional variable-flow controller ACDC, the first Bidirectional variable-flow controller ACDC to lithium battery group, lead-acid battery group limit power, control super capacitance cell group by the 3rd Bidirectional variable-flow controller ACDC and discharge respectively; Judge subsequently whether abnormal power recovers, as recovered, the 3rd energy storage subsystem stops electric discharge; As do not recovered, super capacitance cell group continues electric discharge, at t
isuper capacitance cell group is discharged to its alarm voltage U constantly
c alarmtime, the second Bidirectional variable-flow controller discharges lithium battery group output power limit, by lithium battery group, is discharged; Judge whether abnormal power recovers, as recovered, lithium battery group stops electric discharge again; As do not recovered, continue to discharge into t
i+1constantly, now super capacitance cell group discharges into its protection magnitude of voltage U
c protectionstop electric discharge, lithium ion battery continues electric discharge; To t
i+2 constantlylithium battery group discharges into alarm voltage U
l alarm, the first Bidirectional variable-flow controller ACDC discharges lead-acid battery group output power limit, by lead-acid battery group, starts electric discharge; Again judge whether abnormal power recovers, as recovered, the first energy storage subsystem stops electric discharge; As do not recovered, at t
i+3constantly, lithium battery group is discharged to protection magnitude of voltage U
l protectionstop electric discharge, lead-acid battery group continues electric discharge; To t
i+4lead-acid battery group is discharged to protection magnitude of voltage U constantly
l protectionstop electric discharge, whole mixed energy storage system electric discharge finishes.
When from net, initial T
0constantly calculate each battery pack SOC value, if do not reach set point, each Bidirectional variable-flow controller is protected corresponding battery pack and is forbidden discharging; If reach set point, second, third energy storage subsystem carries out output power limit to lithium battery group, lead-acid battery group, controls super capacitance cell group discharge by the 3rd Bidirectional variable-flow controller ACDC; Judge whether abnormal power recovers, as recovered, stop electric discharge; As do not recovered, continue electric discharge, at T
iconstantly, super capacitance cell group discharges into alarm voltage U
c alarm, the second Bidirectional variable-flow controller ACDC discharges lithium battery group output power limit, by lithium battery group, is discharged; Again judge whether abnormal power recovers, as recovered, stop electric discharge; As do not recovered, at T
i+1super capacitance cell discharges into protection magnitude of voltage U constantly
c protectionstop electric discharge, lithium battery group continues electric discharge; At T
i+2lithium battery group discharges into alarm voltage U constantly
l alarm, the first Bidirectional variable-flow controller discharges lead-acid battery group output power limit, by lead-acid battery group, is discharged; Again judge whether abnormal power recovers, as recovered, stop electric discharge; As do not replied, at T
i+3lithium battery group is discharged to protection magnitude of voltage U constantly
l protectionstop electric discharge, lead-acid battery continues electric discharge; At T
i+4lead-acid battery is discharged to downscale protection voltage U constantly
q protection, stopping electric discharge, whole mixed energy storage system electric discharge finishes.
The mixed energy storage system itself of controlling in order based on energy, comprises its whole topology and electrical structure, function, control strategy etc.Simultaneously, also based on this mixed energy storage system, adopt Selective Control method, by background monitoring system scheduling controlling, realize three kinds of different energy storage carriers and by super capacitor 1 → lithium ion battery 2 → lead-acid battery 3 energy, control in order the principle of utilization, and fully in conjunction with different energy storage carrier pluses and minuses, have complementary advantages, maximize favourable factors and minimize unfavourable ones, a kind of aspect problem methods such as low life-span of energy-storage system of single energy storage carrier of better solution, expensive, low specific energy, low specific power and poor stability are provided.
The invention has the beneficial effects as follows: by abundant utilization and bring into play lead-acid battery, lithium ion battery and super capacitance cell advantage separately, maximize favourable factors and minimize unfavourable ones, adopt Selective Control method by control in order the principle of utilization by super capacitor 1 → lithium ion battery 2 → lead-acid battery 3 energy, met preferably electrical network to energy-storage system in requirements such as aspect of performance high power capacity, long-life, high-energy-density, high-specific-powers, and, the requirement such as floor space little, own wt light low in application aspect cost of investment.
The different energy storage subsystems of this mixed energy storage system, aspect internal control, different energy storage carriers are in charge of by different battery management systems separately respectively, fully guarantee total system data acquisition, upload or pass down and real-time, the accuracy of alarm protection etc., avoid system data transmission phase mutual interference and cause data upload or mistake or the time delay such as biography, fault warning protection down; System grid-connected aspect, different energy storage carriers connect respectively a set of Bidirectional variable-flow controller, adopt Bidirectional variable-flow controller AC parallel method simultaneously, by supervisory control system United Dispatching, control, can independent operating thereby both realized different energy storage subsystems, realize again a whole set of mixed energy storage system overall operation under energy is controlled in order, finally improved this mixed energy storage system operational flexibility and controllability, guaranteed total system safety, stable, reliability service.
When the operation of electrical network, conventionally can produce power fluctuation because of accesses such as wind, light power generating system or high power loads.But while there is short-time pulse power fluctuation in electrical network, can be by preferential the 3rd energy storage subsystem that starts of monitoring and dispatching system, the second Bidirectional variable-flow controller, the first Bidirectional variable-flow controller utilize pulse modulation respectively the second energy storage subsystem, the first energy storage subsystem to be carried out to output power limit simultaneously, fully in conjunction with the 3rd energy storage subsystem super capacitance cell group, compared with high impulse power, handle up and capability of fast response, and discharge and recharge the performance advantages such as number of times height, realized better the 3rd compensation of energy storage subsystem to electrical network short-time pulse power fluctuation.By this control method, both reached the object of level and smooth electrical network short-time pulse peak power, reduce again system to the second energy storage subsystem, the first energy storage subsystem frequent starting, thereby guaranteed on the basis of power grid operation, better improved mixed energy storage system useful life.
When electrical network occurs that lasting power fluctuation or peak of power consumption etc. are abnormal, the 3rd energy storage subsystem provides high-power output in short-term to can not meet far away to improve the abnormal requirement of operation of power networks, and also needing to possess high energy storage system provides more multipotency for the fluctuation of electrical network continuous power or peak of power consumption period.In order to meet electrical network, mixed energy storage system is continued to the needs of Power supply, when the 3rd energy storage subsystem is discharged to protection value, by supervisory control system, start the second energy storage subsystem, by the second energy storage subsystem lithium ion battery group, it is mains supply, in conjunction with lithium ion battery group high-energy-density, compared with advantages such as lead-acid battery group high life, both made up the deficiency of the low stored energy of super capacitance cell group, also the access times of the lead-acid battery group in lower useful life have been reduced simultaneously, improved to a certain extent conventional lead-acid battery energy-storage system volume energy ratio, the shortcoming that weight energy is lower, better met fabricating yard to the high volume energy ratio of energy-storage system, the requirement of high weight energy ratio.The final demand of electrical network to the output of energy-storage system higher-energy that both guaranteed, also improved to a certain extent the whole service life of mixed energy storage system, and better met the strict demand of erecting bed to energy-storage system installation volume, weight etc., fully save and reduce energy-storage system installing space and required load capacity is installed, having improved energy-storage system engineering construction quality.
When electrical network needs how lasting energy to give level and smooth and the second energy storage subsystem institute stored energy of power cannot to meet the demands, start the first energy storage subsystem, in conjunction with the high stored energy of lead-acid battery group, low cost, recoverable rate advantages of higher, can either better meet mixed energy storage system high energy demand, can better make up super capacitance cell group again, lithium ion battery group is expensive, the shortcomings such as recovery utilization rate is low, have improved that conventional energy-storage system is expensive, the deficiency such as low capacity, recoverable rate are low better.
By different energy storage subsystems in mixed energy storage system are controlled in order, the shortcomings such as the single control of energy-storage system, flexibility and the reasonable structure of conventional mixed energy storage system and conventional single energy storage carrier be poor have better been improved, met preferably electrical network to energy-storage system in requirements such as aspect of performance high power capacity, long-life, high-energy-density, high-specific-powers, and, the requirement such as floor space little, own wt light low in application aspect cost of investment.Effectively solve renewable new forms of energy and high power capacity load filling of electric power system hit, realized better electrical network peak load shifting is regulated, finally guaranteed fail safe, stability and the reliability of whole network system operation.
Embodiment
Below in conjunction with accompanying drawing and embodiment, the present invention will be further described.
In Fig. 1, energy storage carrier part: lead-acid battery group 1, lithium battery group 2 and super capacitance cell group 3; Wherein, lead-acid battery group 1 and lithium battery group 2 are as energy type storage battery, fully in conjunction with lead-acid battery and lithium ion battery pluses and minuses, maximize favourable factors and minimize unfavourable ones, make its two kinds of storage batterys reach mutual supplement with each other's advantages at aspects such as up-front investment cost, capacity storage, floor space, useful life and recyclings.As power type super capacitor batteries group 3, possess the above high arteries and veins of sustainable 10s and fill multiplying power discharging advantage, forming and having complementary advantages aspect energy and multiplying power with energy type lead-acid battery group 1 and lithium battery group 2.
Bidirectional variable-flow control section: adopt monopole designs scheme, mainly by the first Bidirectional variable-flow controller ACDC10, the second Bidirectional variable-flow controller ACDC11, the 3rd Bidirectional variable-flow controller ACDC12, be formed by combining, the equal cocoa of each Bidirectional variable-flow controller ACDC module is realized inversion (being DC → AC conversion) and rectification (being AC → DC conversion).Its feature possesses super wide MPPT voltage range, when the first Bidirectional variable-flow controller ACDC10, the second Bidirectional variable-flow controller ACDC11, the 3rd Bidirectional variable-flow controller ACDC12 coordinate with the first main control module BMS4, the second main control module BMS5, the 3rd main control module CMS6 respectively, can exert oneself according to demanded power output and different energy storage carrier battery pack SOC automatic equalization, guarantee that the total run time in all crosstalks pond in unified energy storage carrier reaches unanimity; Possess the functions such as " peak load shifting ", " meritorious, idle control ", " low voltage crossing ", " islet operation " and " failure logging ", wherein the first Bidirectional variable-flow controller ACDC10, the second Bidirectional variable-flow controller ACDC11 also possess respectively to lead-acid battery group 1, lithium battery group 2 current limlitings, limit power functions.Possess and show that analog data that respective battery management system uploads different energy storage carriers is to background monitoring system 13, and accept and assign background monitoring system 13 instructions.
Battery management system part: mainly form from controlling module CM U9 and the first main control module BMS4, the second main control module BMS5, the 3rd main control module BMS6 etc. from control module BMU8, the 3rd from control module BMU7, second by first.Wherein, each is responsible for respectively the functions such as the monitoring such as lead-acid battery group 1, lithium battery group 2, super capacitance cell group 3 voltages, electric current, temperature and alarm and protection, electric quantity balancing from control module, simultaneously by detection information by CAN bus, report each main control module respectively.Each main control module is accepted each and is reported the information such as voltage, temperature, electric current from control mould card, and record discharges and recharges number of times, estimate lead-acid battery group 1, lithium battery group 2, super capacitance cell group 3 dump energies (SOC) simultaneously, assess its health status (SOH) separately; Communicate by letter with background monitoring system 13 in addition, complete and upload lead-acid battery group 1, lithium battery group 2, super capacitance cell group 3 abnormality alarmings, constant data in time between daily record data etc., and the operational order that background monitoring system 13 is issued passes to down respectively each main control module; Secondly communicate by letter with each Bidirectional variable-flow controller, complete and upload lead-acid battery group 1, lithium battery group 2, super capacitance cell group 3 abnormality alarmings, while there is the situations such as overvoltages, under-voltage, overcurrent and excess temperature when lead-acid battery group 1 or lithium battery group 2 or super capacitance cell group 3, ask corresponding Bidirectional variable-flow controller to be realized and discharge and recharge power control, and pass to corresponding main control module under the operational order respectively the first Bidirectional variable-flow controller ACDC10, the second Bidirectional variable-flow controller ACDC11, the 3rd Bidirectional variable-flow controller ACDC12 being issued.
Background monitoring part: background monitoring system 13 communication modes adopt fiber optic Ethernet, there is remote measurement, remote control, remote signaling function, energy storage carrier, battery management system, Bidirectional variable-flow control section and other corollary equipments etc. are carried out to perfect monitoring comprehensively, detect in real time and can check relevant devices running status and running parameter etc.; And grade by long-range control command to the battery management system and Bidirectional variable-flow control part of assigning of background monitoring system 13.
Above-mentioned mixed energy storage system consists of three energy storage subsystems, and the first energy storage subsystem is comprised of from control module BMU7, the first main control module BMS4 and the first Bidirectional variable-flow controller ACDC10 etc. lead-acid battery group 1, first; The second energy storage subsystem is comprised of from control module BMU8, the second main control module BMS5 and the second Bidirectional variable-flow controller ACDC11 etc. lithium battery group 2, second; The 3rd energy storage subsystem is comprised of from control module BMS6 and the 3rd two-way exchange controller ACDC12 etc. super capacitance cell group 3, the 3rd main control module BMU9, the 3rd.Three energy storage subsystems pass through respectively the first two-way exchange controller ACDC10, the second two-way exchange controller ACDC11, the 3rd two-way exchange controller ACDC12 in its AC parallel connection, and by background monitoring system 13 dispatch realize three energy storage subsystems can independent operating, common operation can cooperatively interact again.
Above-mentioned mixed energy storage system is by background monitoring system 13 scheduling controlling, and by power network monitoring and evaluates calculation, this mixed energy storage system controlling run strategy as shown in Figure 2.
While occurring that instantaneous power exceeds target power scope, concrete charge and discharge process is: first judge whether each battery pack SOC reaches set point, as do not reach, each Bidirectional variable-flow controller is protected each battery pack, and forbids electric discharge; If reached, at t
0constantly, the second Bidirectional variable-flow controller ACDC11, the first Bidirectional variable-flow controller ACDC10 to lithium battery group, lead-acid battery group limit power, control super capacitance cell group by the 3rd Bidirectional variable-flow controller ACDC12 and discharge respectively; Judge subsequently whether abnormal power recovers, as recovered, the 3rd energy storage subsystem stops electric discharge; As do not recovered, super capacitance cell group continues electric discharge, at t
isuper capacitance cell group is discharged to its alarm voltage U constantly
c alarmtime, the second Bidirectional variable-flow controller discharges lithium battery group output power limit, by lithium battery group, is discharged; Judge whether abnormal power recovers, as recovered, lithium battery group stops electric discharge again; As do not recovered, continue to discharge into t
i+1constantly, now super capacitance cell group discharges into its protection magnitude of voltage U
c protectionstop electric discharge, lithium ion battery continues electric discharge; To t
i+2 constantlylithium battery group discharges into alarm voltage U
l alarm, the first Bidirectional variable-flow controller ACDC10 discharges lead-acid battery group output power limit, by lead-acid battery group, starts electric discharge; Again judge whether abnormal power recovers, as recovered, the first energy storage subsystem stops electric discharge; As do not recovered, at t
i+3constantly, lithium battery group is discharged to protection magnitude of voltage U
l protectionstop electric discharge, lead-acid battery group continues electric discharge; To t
i+4lead-acid battery group is discharged to protection magnitude of voltage U constantly
l protectionstop electric discharge, whole mixed energy storage system electric discharge finishes.
When from net, initial T
0constantly calculate each battery pack SOC value, if do not reach set point, each Bidirectional variable-flow controller is protected corresponding battery pack and is forbidden discharging; If reach set point, second, third energy storage subsystem carries out output power limit to lithium battery group, lead-acid battery group, controls super capacitance cell group discharge by the 3rd Bidirectional variable-flow controller ACDC12; Judge whether abnormal power recovers, as recovered, stop electric discharge; As do not recovered, continue electric discharge, at T
iconstantly, super capacitance cell group discharges into alarm voltage U
c alarm, the second Bidirectional variable-flow controller ACDC11 discharges lithium battery group output power limit, by lithium battery group, is discharged; Again judge whether abnormal power recovers, as recovered, stop electric discharge; As do not recovered, at T
i+1super capacitance cell discharges into protection magnitude of voltage U constantly
c protectionstop electric discharge, lithium battery group continues electric discharge; At T
i+2lithium battery group discharges into alarm voltage U constantly
l alarm, the first Bidirectional variable-flow controller discharges lead-acid battery group output power limit, by lead-acid battery group, is discharged; Again judge whether abnormal power recovers, as recovered, stop electric discharge; As do not replied, at T
i+3lithium battery group is discharged to protection magnitude of voltage U constantly
l protectionstop electric discharge, lead-acid battery continues electric discharge; At T
i+4lead-acid battery is discharged to downscale protection voltage U constantly
q protection, stopping electric discharge, whole mixed energy storage system electric discharge finishes.