Multi-energy complementary electrochemical energy storage system adaptive to load power abrupt change

Abstract

The invention relates to the field of electrochemical energy storage systems, in particular to a multi-energy complementary electrochemical energy storage system adaptive to load power abrupt change, which comprises a multi-source energy supply component, a power conversion module, an instantaneous power compensation unit (supercapacitor), a direct current bus, an energy storage converter and a central controller. The multi-source energy supply assembly is connected to the direct-current bus through the corresponding power conversion module, the super capacitor is directly connected with the direct-current bus, the energy storage converter is connected with the direct-current bus and the load, and the central controller is connected with all the assemblies. And when the load instantaneous power abrupt change exceeds a threshold value and the bus voltage deviates from an allowable range, the supercapacitor automatically triggers charging and discharging response, releases or absorbs peak current, and fills a power gap. According to the system, instantaneous load compensation is undertaken through the supercapacitor, a low-rate lithium battery and multi-energy priority power supply and dynamic power distribution are matched, an impact load is quickly responded, meanwhile, the system cost is reduced, the power supply stability and safety are improved, and the energy utilization efficiency is optimized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemical energy storage systems, in particular to a multi-energy complementary electrochemical energy storage system suitable for adapting to sudden changes in load power. BACKGROUND

[0002] In the field of multi-energy complementary energy storage, in the traditional system architecture shown in Figure 1 , the electrical energy output by the diesel generator and the photovoltaic system is converted into alternating current through power conversion units such as AC / DC modules and maximum power point tracking (MPTT) modules, then integrated into the DC bus and coupled with the lithium battery on the DC side, and the coupled electrical energy is converted into alternating current through the energy storage converter (PCS), and finally the required alternating current is output to provide power support for various loads. This architecture can realize basic collaborative scheduling of multiple energies and meet the power demand of conventional smooth loads. It is a widely used multi-energy complementary energy storage topology in the industry.

[0003] However, in actual application scenarios, the existing multi-energy complementary energy storage system still has the following technical bottlenecks: First, the response performance to impact loads is insufficient: for the instantaneous power surge demand of impact loads, the energy side needs to have millisecond-level fast response capability, but the dynamic response speed of core energy units such as diesel generators and photovoltaic systems cannot meet this requirement, and only lithium batteries can be relied on to undertake instantaneous power compensation tasks.

[0004] Second, there is a contradiction in the adaptability of lithium batteries: although power-type lithium batteries support high-rate instantaneous discharge, their cycle life is short and they need to be replaced frequently during long-term operation, resulting in increased system maintenance costs; energy storage-type lithium batteries have more advantages in cycle life, but they cannot achieve high-rate discharge. If a multi-cell parallel topology is used to obtain large current output, it will not only significantly increase the system hardware cost, but also may cause circulating current phenomenon, which not only increases the design complexity of the system, but also brings additional safety hazards.

[0005] Third, system stability and safety are limited: when facing impact loads, the system is difficult to quickly achieve power supply and demand balance, which easily leads to fluctuations in DC bus voltage, affecting power supply stability; at the same time, the design scheme of multi-cell parallel connection further increases the probability of safety accidents such as thermal runaway, restricting the improvement of system safety performance. SUMMARY

[0006] To this end, the present application aims to solve the technical problems that the traditional multi-energy complementary energy storage system cannot achieve millisecond-level response on the energy side when facing impact / step load, has contradictory adaptability of lithium batteries, and is limited in system stability and safety, thereby providing a multi-energy complementary electrochemical energy storage system adapting to load power mutation, comprising a multi-source energy supply component, a plurality of power conversion modules, an instantaneous power compensation unit, a DC bus, an energy storage converter, and a central controller, wherein, According to the power supply priority, the multi-source energy supply component is divided into a first energy module, a second energy module, and a third energy module; The multi-source energy supply component is connected to each of the plurality of power conversion modules one by one, and is connected to the DC input end of the DC bus through the plurality of power conversion modules; at the same time, the instantaneous power compensation unit is connected to the DC input end of the DC bus; The DC input end of the energy storage converter is connected to the DC output end of the DC bus, and the AC output end of the energy storage converter is connected to the load; The central controller is connected to the multi-source energy supply component, the plurality of power conversion modules, the instantaneous power compensation unit, the energy storage converter, and the load, respectively; When the instantaneous power mutation amplitude of the load exceeds the preset power threshold range, and the voltage of the DC bus deviates from the allowed range, the instantaneous power compensation unit automatically triggers the charging and discharging response based on the voltage-power mutation perception signal, releases or absorbs the peak current within a preset time length, fills the instantaneous power gap, and stabilizes the voltage of the DC bus within the allowed range; When the load power tends to be stable, the DC bus voltage returns to the rated allowed range, and the central controller confirms that other power modules are not needed to intervene to make up the charging and discharging power gap of the instantaneous power compensation unit through real-time detection of the operating state parameters of the instantaneous power compensation unit and determination of the load power fluctuation time length, the instantaneous power compensation unit automatically switches to the standby state to prepare for responding to subsequent load power mutation requirements.

[0007] In an embodiment of the present application, when the power of the load is stepwise mutated and the mutation amplitude exceeds the preset power threshold range, the load is compensated in two stages, specifically including: In the first stage, the output voltage of each power module is adjusted to dynamically adjust the DC bus voltage, and the instantaneous power compensation unit is triggered to respond autonomously based on the difference between the DC bus voltage and the voltage of the instantaneous power compensation unit, to release or absorb the peak current within a preset time length, fill the instantaneous power gap, and stabilize the DC bus voltage within the rated allowed range; In the second stage, that is, while the instantaneous power compensation unit is responding, the central controller issues adjustment instructions to the corresponding power conversion modules based on the real-time collected state data of each energy module, so as to control the energy module and the instantaneous power compensation unit to jointly fill the power gap after the load occurs step mutation; When the load power tends to be stable, and the DC bus voltage and the instantaneous power compensation unit voltage reach balanced matching and return to the rated allowable range, the instantaneous power compensation unit automatically stops the charging and discharging action, enters a stable state without energy interaction, and then switches to a standby mode to prepare for responding to subsequent load power mutation requirements.

[0008] In an embodiment of the present application, when the central controller monitors that the remaining power parameter of the instantaneous power compensation unit is lower than the preset standby threshold, the central controller controls to send a power supply instruction to any power conversion module, and based on the power supply instruction, the corresponding energy module charges the instantaneous power compensation unit until the remaining power parameter of the instantaneous power compensation unit returns to the preset response threshold.

[0009] In an embodiment of the present application, the control of the energy module and the instantaneous power compensation unit to jointly fill the power gap after the load occurs step mutation specifically includes: determining whether the first energy module meets a preset power compensation threshold: If yes, the central controller sends a first adjustment instruction to the power conversion module on the side of the first energy module, and based on the first adjustment instruction, the first energy module increases its output power, jointly fills the power gap after the load occurs step mutation with the instantaneous power compensation unit, and simultaneously preferentially charges the second energy module; If no, the central controller sends a second adjustment instruction to the power conversion module on the side of the second energy module, and based on the second adjustment instruction, the second energy module increases its output power, jointly fills the power gap after the load occurs step mutation with the instantaneous power compensation unit, and simultaneously continuously monitors the remaining power parameter of the second energy module, and if the remaining power parameter is lower than a lower limit value, the central controller sends a third adjustment instruction to the power conversion module on the side of the third energy module, and based on the third adjustment instruction, the third energy module increases its output power, jointly fills the power gap after the load occurs step mutation with the instantaneous power compensation unit, and simultaneously preferentially charges the second energy module.

[0010] In an embodiment of the present application, the central controller acquires the electrical energy parameter of the instantaneous power compensation unit, and adjusts the droop curve parameter of the energy storage converter based on the electrical energy parameter.

[0011] In an embodiment of the present application, the central controller acquires state parameters of all the energy modules, and dynamically adjusts power distribution ratios of all the energy modules based on the state parameters to generate power adjustment instructions and send the power adjustment instructions to corresponding power conversion modules on the energy module side.

[0012] In an embodiment of the present application, the state parameters include a remaining power parameter and temperature data.

[0013] In an embodiment of the present application, when the central controller monitors that the power of the load is in a stable state and the stable duration exceeds a preset duration threshold, the central controller controls power supply start of the first energy module, the second energy module and the third energy module in a priority order, including:

[0014] The first energy module is first started to supply power to the load, when the output power of the first energy module is greater than the power supply demand of the load, the excess power flows to the second energy module through the DC bus for storage until the remaining power parameter of the second energy module reaches a preset upper limit value.

[0015] When the output power of the first energy module is lower than the power supply demand of the load, a start instruction is sent to the power conversion module on the second energy module side to control the second energy module to release power to access the DC bus and supply power cooperatively with the first energy module.

[0016] When the remaining power of the second energy module is lower than a preset lower limit value and the first energy module cannot supply power to the load, a start instruction is sent to the power conversion module on the third energy module side to control the third energy module to supply power to the load and charge the second energy module at the same time.

[0017] In an embodiment of the present application, the first energy module is a photovoltaic cell, the second energy module is a lithium battery, and the third energy module is a diesel generator.

[0018] In an embodiment of the present application, the instantaneous power compensation unit is a super capacitor.

[0019] The above technical solution of the present application has the following beneficial effects compared with the prior art: Firstly, by introducing a super capacitor to undertake the power compensation task of instantaneous impact / step load, and by matching a low-rate long-time energy storage lithium battery as a basic energy supply, the problem of short cycle life and frequent replacement of power-type lithium batteries is avoided, and there is no need to use a multi-cell parallel design to obtain a large current, which greatly reduces the system cost and the risk of thermal runaway, and at the same time, the response speed of the impact load is improved from 100 ms of the traditional system to within 10 ms, which significantly improves the response efficiency. Secondly, relying on the dynamic adaptive power distribution algorithm based on the SOC, temperature and other parameters of the super capacitor and lithium battery, combined with the priority power supply logic of the multi-source energy supply component, efficient collaborative scheduling of various types of energy can be realized, clean energy is preferentially used to optimize energy utilization efficiency, and non-clean energy consumption is reduced. Thirdly, the system adopts a direct current bus platform, cooperates with the instantaneous stabilizing effect of the super capacitor on the bus voltage and the dynamic adjustment of the droop curve of the energy storage converter, effectively suppresses the bus voltage fluctuation when the load power suddenly changes, improves the power supply stability, and the overall architecture reduces the operation pressure of each device by clearly defining the function division of each component (the super capacitor only responds to instantaneous demand, and other energy sources bear long-time stable load), prolongs the overall service life of the system, and balances safety, economy and reliability. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings.

[0021] Figure 1 is a structural schematic diagram of a traditional multi-energy complementary electrochemical energy storage system; Figure 2 is a structural schematic diagram of a multi-energy complementary electrochemical energy storage system provided in an embodiment of the present application and adapted to sudden changes in load power; Figure 3 is a schematic diagram of a sudden impact mutation in load power; Figure 4 is a schematic diagram of a step mutation in load power.

[0022] Description of the Drawings: 1, multi-source energy supply component; 11, first energy module, 12, second energy module; 13, third energy module; 2, power conversion module; 3, instantaneous power compensation unit; 4, direct current bus; 5, energy storage converter; 6, central controller; 100, load. DETAILED DESCRIPTION

[0023] The present application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it, but the embodiments are not limiting to the present application.

[0024] As shown in Figure 2 The present application also provides a multi-energy complementary electrochemical energy storage system adapted to sudden changes in load power, comprising: a multi-source energy supply component 1, a plurality of power conversion modules 2, an instantaneous power compensation unit 3, a direct current bus 4, an energy storage converter 5 and a central controller 6; wherein, The multi-source energy supply assembly 1 is divided into a first energy module 11, a second energy module 12 and a third energy module 13 based on power supply priority; the first energy module 11 is a photovoltaic cell; the second energy module 12 is a lithium battery, preferably a lithium iron phosphate battery; and the third energy module 13 is a diesel generator, which jointly bear the power supply task of long-time stable load. Each energy module in the multi-source energy supply assembly 1 is connected to one of the plurality of power conversion modules 2 one by one, and is connected to the DC input end of the DC bus 4 through the plurality of power conversion modules 2; specifically, the power conversion module 2 corresponding to the first energy module 11 is a maximum power point tracking (MPTT) module, the power conversion module 2 corresponding to the second energy module 12 is a DC / DC converter, and the power conversion module 2 corresponding to the third energy module 13 is an AC / DC converter, which ensures that the output of each type of energy is adapted to the requirements of the DC bus 4. Meanwhile, the transient power compensation unit 3 selects a super capacitor, which has high power density and long cycle life, to specifically respond to the sudden demand of the transient impact power and step change power of the load 100, and is connected to the DC input end of the DC bus 4. The DC bus 4 adopts an 800V voltage platform (adaptation range 600Vdc-1500Vdc) as the energy transmission hub of each type of energy module, the transient power compensation unit 3 and the energy storage converter 5, realizing centralized coupling on the DC side. The DC input end of the energy storage converter 5 is connected to the DC output end of the DC bus 4, and the AC output end of the energy storage converter 5 is connected to the load 100, completing direct-to-alternate conversion and providing stable AC power to the load 100. The central controller 6 is connected to the multi-source energy supply assembly 1, the plurality of power conversion modules 2, the transient power compensation unit 3, the energy storage converter 5 and the load 100 as the system control core, and collects real-time component state data and issues control instructions.

[0025] Based on the above system structure, the system uses a control logic combining transient compensation and collaborative energy supply, realizes differentiated control for the two scenarios of transient impact mutation and step mutation of the load 100, and guarantees efficient and stable operation of the system through priority power supply and dynamic power distribution.

[0026] Further, under normal load power supply conditions, when the central controller 6 monitors that the power of the load 100 is in a stable state and the stable duration exceeds the preset duration threshold, the first energy module 11 (i.e. photovoltaic cell), the second energy module 12 (i.e. lithium battery) and the third energy module 13 (i.e. diesel generator) are controlled by the corresponding power conversion module 2 to supply power to the load 100 according to the priority of "photovoltaic priority → lithium battery supplement → diesel generator backup". The specific process is as follows: Following the power supply priority of the first energy module 11, the first energy module 11 (photovoltaic cell) is triggered to start, and through the matched maximum power point tracking (MPTT) converter, it is connected to the DC bus 4 to preferentially provide power for the load 100; if the output power (P_PV) of the photovoltaic cell is greater than the demand power (P_Load) of the load 100, the excess power is guided to the second energy module 12 (lithium battery pack) through the DC bus 4, and the power conversion module 2 (DC / DC converter) on the lithium battery side is used to realize charging and consumption until the remaining capacity parameter (SOC_batt) of the lithium battery reaches the preset upper limit value; When the output power (P_PV) of the photovoltaic cell is lower than the demand power (P_Load) of the load 100, a start instruction is sent to the DC / DC converter on the lithium battery side to control the lithium battery to release power and connect to the DC bus 4 to supply power cooperatively with the photovoltaic cell, so as to ensure the balance between supply and demand of load power; When the remaining capacity parameter (SOC_batt) of the lithium battery is lower than the preset discharge lower limit value, and the photovoltaic cell cannot meet the power supply demand of the load 100 due to insufficient light and other reasons, a start instruction is sent to the power conversion module 2 (AC / DC converter) on the third energy module 13 (diesel generator) side to trigger the diesel generator to operate; the output power of the diesel generator is rectified by the AC / DC converter and connected to the DC bus 4, which on the one hand provides basic power supply for the load 100, and on the other hand charges the lithium battery pack through the DC / DC converter to ensure the basic energy reserve of the system.

[0027] Further, as shown in Figure 3 Under the impact load power supply condition, when the instantaneous power of the load 100 suddenly changes by more than the preset power threshold range, and the voltage of the DC bus 4 deviates from the allowed range, the following instantaneous compensation response mechanism is started: The instantaneous power compensation unit 3 (supercapacitor) automatically triggers the charging and discharging response based on the voltage-power mutation perception signal, releases or absorbs the peak current within the preset millisecond duration (10ms), quickly fills the instantaneous power gap, and stabilizes the voltage of the DC bus 4 within the allowed range; When the power of the load 100 tends to be stable, and the DC bus 4 voltage returns to the rated value, the central controller 6 confirms that there is no need for other power modules to intervene to make up for the charge and discharge power gap of the transient power compensation unit 3 after real-time detection of the operating state parameters of the transient power compensation unit 3 and determination of the load power fluctuation time length, and the transient power compensation unit 3 automatically switches to the standby state to prepare for responding to the subsequent load 100 power mutation demand.

[0028] When the power of the load 100 presents a step mutation (such as Figure 4 1~3 segments, accompanied by impact 4 segments, impact 5 segments, etc. transient mutation), and the mutation amplitude exceeds the preset power threshold range, the system adopts a two-stage response mechanism of "transient compensation + coordinated power supply" to compensate the power of the load 100, which specifically includes: In the first stage of transient impact compensation (corresponding to impact 4 segment and impact 5 segment in step mutation), the output voltage of each power module is adjusted to dynamically adjust the DC bus 4 voltage, and the super capacitor is triggered to respond autonomously based on the difference between the DC bus 4 voltage and the super capacitor voltage, to release or absorb peak current within 10ms, to stabilize the voltage of the DC bus 4 within the allowable range, and to avoid voltage fluctuation affecting the operation of the load 100; In the second stage of multi-energy coordinated power supply (corresponding to Figure 4 1 / 2 / 3 segments), while the super capacitor is responding to the transient impact compensation, the central controller 6 collects the state data of each energy module (output power P_PV of photovoltaic cell, SOC data SOC_Batt and temperature data T_Batt of lithium battery, operating state data of diesel generator) in real time, and sends adjustment instructions to the corresponding power conversion module 2 to control each energy module and the super capacitor to cooperatively fill the power gap of the load 100 after the step mutation, and the specific logic is as follows: Firstly, it is determined whether the output power P_PV of the photovoltaic cell meets the preset power compensation threshold ΔP_Load_step, and ΔP_Load_step is the step mutation power difference: If yes, the central controller 6 sends a first adjustment instruction to the MPPT module on the photovoltaic cell side, and based on the first adjustment instruction, the photovoltaic cell increases its output power to cooperatively fill the power gap of the load 100 after the step mutation with the super capacitor; at the same time, if the photovoltaic cell has excess energy, it is preferentially charged to the lithium battery through the DC / DC converter; If not, the central controller 6 sends a second adjustment instruction to the DC / DC converter on the lithium battery side, based on which the lithium battery increases its output power to fill the power gap after the load 100 experiences a step change, in cooperation with the super capacitor; in this process, the central controller 6 continuously monitors the remaining capacity parameter SOC_Batt of the lithium battery: If the SOC_Batt is higher than the lower limit value, the current cooperative mode is maintained; If the SOC_Batt is lower than the lower limit value, the central controller 6 sends a third adjustment instruction to the AC / DC converter on the diesel generator side, based on which the diesel generator increases its output power to fill the power gap after the load 100 experiences a step change, in cooperation with the super capacitor and the lithium battery (if the remaining capacity allows); at the same time, the excess power of the diesel generator is preferentially used to charge the lithium battery until the SOC_Batt rises to the safe range; After the load 100 enters the stable stage (corresponding to Figure 4 When the DC bus 4 and the super capacitor voltage reach a balanced match and return to the rated allowable range, the super capacitor automatically stops charging and discharging and enters a stable state without energy interaction, and then switches to a standby mode, in which the photovoltaic cell, the lithium battery, and the diesel generator dynamically allocate the power supply proportion based on the state parameters to maintain long-term stable operation of the system.

[0029] Further, in the above embodiment, to ensure the operation safety of the instantaneous power compensation unit 3 and the energy storage unit, the central controller 6 dynamically and adaptively adjusts the droop curve of the energy storage converter 5 based on multi-dimensional state parameters, avoids over-discharging of the super capacitor, and ensures that the super capacitor is always in the best response state. The specific process is as follows: The output power and voltage amplitude of the energy storage converter 5 (PCS) are collected in real time to capture the basic data of the equipment operation state; and the remaining capacity (SOC_UC) of the instantaneous power compensation unit 3 (super capacitor), the remaining capacity parameter (SOC_batt) of the second energy module 12 (lithium battery), and the temperature data of the lithium battery and other core state parameters are collected synchronously to build a multi-dimensional parameter monitoring system and provide decision input for adaptive adjustment; Based on the dynamic adaptive power distribution algorithm based on the state parameters of the super capacitor and the lithium battery, the multi-dimensional data collected above are fused to accurately calculate the dynamic droop control coefficient Dp of the energy storage converter 5; When the lithium battery SOC_batt is in a preset normal range and meets the basic power supply reserve requirements of the system, the super capacitor SOC_UC is used as the core adjustment basis: If SOC_UC is lower than the preset response threshold, increase the dynamic droop control coefficient Dp to make the working mode of the energy storage converter 5 deviate to preferentially charge the super capacitor, so as to ensure the rapid recovery of the transient response capability; If SOC_UC is higher than the preset response threshold, decrease the dynamic droop control coefficient Dp to make the super capacitor enter the discharging standby state, so as to respond to the sudden load power change demand. No matter the SOC_UC of the super capacitor is in any state, the lithium battery power supply reserve is preferentially guaranteed: if SOC_batt is lower than the preset lower limit value, increase the dynamic droop control coefficient Dp, the system preferentially charges the lithium battery, and builds a solid system foundation power supply guarantee; if SOC_batt is higher than the preset upper limit value, decrease the dynamic droop control coefficient Dp, guide the lithium battery to preferentially discharge, avoid overcharging risk, and optimize energy utilization efficiency.

[0030] To ensure that the super capacitor group always has transient response capability, the central controller 6 sets up an electric quantity maintenance mechanism: When the central controller 6 monitors that the SOC_UC of the super capacitor is lower than the preset standby threshold, by controlling to send a power supply instruction to any power conversion module 2, based on the power supply instruction, the corresponding energy module charges the super capacitor through the DC bus 4, until the remaining electric quantity parameter SOC_UC of the super capacitor rises to the preset response threshold, and after completing the electric quantity supplement, switches to the standby state, so as to ensure that the super capacitor can respond to load mutation at any time.

[0031] Further, in the above embodiment, the central controller 6 also acquires the state parameters of all the energy modules in real time, such as the output power P_PV of the photovoltaic cell, the efficiency η_MPPT of the MPPT module, the remaining electric quantity parameter SOC_Batt and temperature data T_Batt of the lithium battery, and the running state data (output power P_Gen and fuel efficiency η_Gen) of the diesel generator. Based on the principle of clean energy priority and efficiency optimization, the output power proportion of each energy module is adjusted through a dynamic power distribution algorithm, power adjustment instructions are generated and issued to the corresponding power conversion module 2, energy efficient utilization is realized, clean energy consumption rate is maximized, and non-clean energy (diesel generator) consumption is reduced.

[0032] When the output power P_PV of the first energy module 11 (photovoltaic cell) meets the preset sufficient condition (i.e. photovoltaic output power P_PV≥load rated power P_Load_rated, and it is in stable power generation state through the MPPT module), the system realizes power scheduling according to the following logic: Under normal load power supply conditions, the central controller 6 controls the photovoltaic cell to access the DC bus 4 through the corresponding maximum power point tracking (MPPT) module, in accordance with the first energy module 11 priority power supply priority, to preferentially provide power for the load; when the photovoltaic output power exceeds the load demand, the excess power is guided to the second energy module 12 (lithium battery) through the DC bus 4, and the charging is realized through the lithium battery side DC / DC power conversion module, until the lithium battery remaining power (SOC_batt) reaches the preset upper limit value, to avoid waste of photovoltaic energy.

[0033] Under impact load power supply conditions, when the central controller 6 monitors that the load instantaneous power mutation amplitude exceeds the preset threshold, and the DC bus 4 voltage deviates from the allowed range, the cooperative power supply mechanism is triggered: Firstly, the instantaneous power compensation unit 3 (supercapacitor) releases the peak current within 10ms to quickly fill the instantaneous power gap to stabilize the bus voltage; at the same time, the central controller 6 adjusts the output power of the photovoltaic cell to the maximum available value based on the real-time output state of the photovoltaic cell through the MPPT module, and controls the lithium battery to release power through the lithium battery side DC / DC module, to form a "photovoltaic cell + supercapacitor + lithium battery" cooperative power supply mode, to continuously match the power demand of the impact load until the load power recovers smoothly.

[0034] When the output power of the first energy module (photovoltaic cell) is lower than the rated power of the load (i.e. the photovoltaic energy is insufficient), or the photovoltaic cell cannot stably supply power due to fluctuation of light conditions, the system realizes power scheduling according to the following logic: Under normal load power supply conditions, the central controller 6 preferentially starts the second energy module 12 (lithium battery), and the power is accessed to the DC bus through the DC / DC power conversion module on the side of the lithium battery to provide basic power supply for the load; if the output power of the lithium battery cannot meet the load demand, the central controller 6 triggers the third energy module 13 (diesel generator) to start, and the diesel generator accesses the DC bus through the AC / DC power conversion module and outputs power according to its preset optimal working power point (the optimal power interval matching the fuel efficiency and running stability of the diesel generator); at this time, the difference between the total power required by the load and the optimal output power of the diesel generator is supplemented by the lithium battery through the DC / DC module to dynamically adjust the output power, to ensure that the diesel generator always operates in high-efficiency and stable working condition, while avoiding over-discharge of the lithium battery.

[0035] In the case of impact load power supply, in view of the fact that the dynamic response speed of the third energy module 13 (diesel generator) cannot meet the millisecond-level transient power compensation demand, when the load impact is monitored, the central controller 6 preferentially controls the transient power compensation unit 3 (supercapacitor) to release the peak current within 10 ms to quickly stabilize the DC bus 4 voltage; at the same time, the lithium battery side DC / DC module adjusts the lithium battery output power to collaboratively fill the power gap of the impact load with the supercapacitor, forming a "lithium battery + supercapacitor" transient collaborative power supply mode; in this process, the diesel generator maintains the optimal working power output and only undertakes the basic power supply task of the normal load and does not participate in the transient impact power compensation.

[0036] In order to guarantee the system operation safety, the central controller 6 implements the charge and discharge permission control of the lithium battery group and the supercapacitor group based on the state parameters: the core state parameters of the second energy module 12 (lithium battery) and the transient power compensation unit 3 (supercapacitor) are collected in real time, the charge and discharge permission control is realized based on the preset threshold, and the specific logic is as follows: The lithium battery remaining capacity (SOC batt) and temperature data (T batt) are monitored in real time: when the SOC batt is lower than the preset discharge lower limit value (the minimum reserve capacity for guaranteeing the lithium battery cycle life) or higher than the preset charge upper limit value (to avoid overcharge risk), the corresponding charge and discharge operation of the lithium battery is prohibited; when the T batt exceeds the preset safe temperature range (temperature interval for avoiding thermal runaway risk), no matter what state the SOC batt is in, the lithium battery charge and discharge circuit is immediately cut off and it is prohibited from participating in power dispatching.

[0037] The supercapacitor remaining capacity (SOC UC) is monitored in real time: when the SOC UC is lower than the preset discharge threshold (to ensure the minimum capacity of transient response capability), the supercapacitor is prohibited from discharging and is only allowed to be charged through the energy module; when the SOC UC is higher than the preset charge threshold (to avoid the maximum capacity of overcharge damage), the supercapacitor is prohibited from charging and is only maintained in the discharging standby state; if it is monitored that the supercapacitor temperature exceeds the safe range, the charge and discharge operation of the supercapacitor is also prohibited to guarantee the system safety.

[0038] Obviously, the above embodiments are merely examples for clear illustration and are not a limitation on the implementation. For those of ordinary skill in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the implementation is not required or can not be exhausted. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A multi-energy complementary electrochemical energy storage system adapted to accommodate load power surges, characterized by, include: The system includes multi-source power supply components, multiple power conversion modules, instantaneous power compensation units, DC buses, energy storage converters, and a central controller; among which, According to the power supply priority, the multi-source power supply components are divided into a first energy module, a second energy module and a third energy module; The multi-source power supply component is connected to each of the multiple power conversion modules in a corresponding manner, and is connected to the DC input terminal of the DC bus through the multiple power conversion modules; at the same time, the instantaneous power compensation unit is connected to the DC input terminal of the DC bus. The DC input terminal of the energy storage converter is connected to the DC output terminal of the DC bus, and the AC output terminal of the energy storage converter is connected to the load. The central controller is connected to the multi-source power supply component, the multiple power conversion modules, the instantaneous power compensation unit, the energy storage converter, and the load, respectively. When the instantaneous power fluctuation of the load exceeds the preset power threshold range and the voltage of the DC bus deviates from the allowable range, the instantaneous power compensation unit automatically triggers a charging and discharging response based on the voltage-power fluctuation sensing signal, releases or absorbs peak current within a preset time to fill the instantaneous power gap and stabilize the voltage of the DC bus within the allowable range. When the load power stabilizes, the DC bus voltage returns to the rated allowable range, and the central controller confirms that no other power module needs to be involved to make up for the charging and discharging power gap of the instantaneous power compensation unit by real-time detection of the operating status parameters of the instantaneous power compensation unit and determination of the duration of load power fluctuations, the instantaneous power compensation unit automatically switches to standby mode in preparation to respond to subsequent load power surges.

2. The multi-energy complementary electrochemical energy storage system adapting load power abrupt change according to claim 1, characterized in that, When the power of the load changes abruptly in a stepped manner, and the magnitude of the change exceeds a preset power threshold range, power compensation for the load is performed in two stages, specifically including: In the first stage, the DC bus voltage is dynamically adjusted by regulating the output voltage of each power module. Based on the difference between the DC bus voltage and the voltage of the instantaneous power compensation unit, the instantaneous power compensation unit is triggered to respond autonomously, releasing or absorbing peak current within a preset time to fill the instantaneous power gap and stabilize the DC bus voltage within the rated allowable range. In the second stage, that is, while the instantaneous power compensation unit is responding, the central controller, based on the real-time collected status data of each energy module, sends adjustment commands to the corresponding power conversion module, controlling the energy module and the instantaneous power compensation unit to work together to fill the power gap after the load undergoes a step change. When the load power stabilizes and the DC bus voltage and the instantaneous power compensation unit voltage reach a balanced match and return to the rated allowable range, the instantaneous power compensation unit automatically stops charging and discharging and enters a stable state without energy interaction. Then it switches to standby mode to prepare to respond to subsequent sudden changes in load power demand.

3. A multi-energy complementary electrochemical energy storage system adapted to load power surges according to claim 1 or 2, characterized in that, When the central controller monitors that the remaining power parameter of the transient power compensation unit is lower than a preset standby threshold, the central controller controls sending a power supply instruction to any power conversion module, and based on the power supply instruction, the corresponding energy module charges the transient power compensation unit until the remaining power parameter of the transient power compensation unit rises to a preset response threshold.

4. The multi-energy complementary electrochemical energy storage system adapting load power abrupt change according to claim 2, characterized in that, The central controller controls the energy module and the transient power compensation unit to jointly fill the power gap after the load occurs step mutation, specifically including: determining whether the first energy module meets a preset power compensation threshold: if yes, the central controller sends a first adjustment instruction to the power conversion module on the first energy module side, and based on the first adjustment instruction, the first energy module increases its output power, and jointly fills the power gap after the load occurs step mutation with the transient power compensation unit, while preferentially charging the second energy module; if no, the central controller sends a second adjustment instruction to the power conversion module on the second energy module side, and based on the second adjustment instruction, the second energy module increases its output power, and jointly fills the power gap after the load occurs step mutation with the transient power compensation unit, while continuously monitoring the remaining power parameter of the second energy module, and if the remaining power parameter is lower than a lower limit value, the central controller sends a third adjustment instruction to the power conversion module on the third energy module side, and based on the third adjustment instruction, the third energy module increases its output power, and jointly fills the power gap after the load occurs step mutation with the transient power compensation unit, while preferentially charging the second energy module.

5. The multi-energy complementary electrochemical energy storage system adapting to load power abrupt change according to claim 4, characterized in that, The central controller obtains the power parameter of the transient power compensation unit, and adjusts the droop curve parameter of the energy storage converter based on the power parameter.

6. The multi-energy complementary electrochemical energy storage system adapting load power abrupt change according to claim 1, characterized in that, The central controller obtains the state parameter of all the energy modules, and dynamically adjusts the power distribution ratio of all the energy modules based on the state parameter to generate a power adjustment instruction and send it to the power conversion module on the corresponding energy module side.

7. The multi-energy complementary electrochemical energy storage system adapting to load power abrupt change according to claim 6, characterized in that, The state parameter includes a remaining power parameter and temperature data.

8. The multi-energy complementary electrochemical energy storage system adapting load power abrupt change according to claim 1, characterized in that, When the central controller monitors that the power of the load is in a stable state and the stable duration exceeds a preset duration threshold, the central controller controls the power supply start of the first energy module, the second energy module and the third energy module in priority order, including: first starting the first energy module to supply power to the load, when the output power of the first energy module is greater than the power supply demand of the load, the excess power flows to the second energy module for storage through the DC bus until the remaining power parameter of the second energy module reaches a preset upper limit value; when the output power of the first energy module is lower than the power supply demand of the load, a start instruction is sent to the power conversion module on the second energy module side to control the second energy module to release power to access the DC bus and supply power with the first energy module; When the remaining power of the second energy module is lower than a preset lower limit value and the first energy module cannot supply power to the load, a start instruction is sent to the power conversion module on the third energy module side to control the third energy module to supply power to the load while charging the second energy module.

9. The multi-energy complementary electrochemical energy storage system adapted to accommodate load power surges of any one of claims 1-8, wherein, The first energy module is a photovoltaic cell, the second energy module is a lithium battery, and the third energy module is a diesel generator.

10. The multi-energy complementary electrochemical energy storage system adapted to accommodate load power surges according to any one of claims 1-8, wherein, The instantaneous power compensation unit is a super capacitor.

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