911 results about "Battery energy storage system" patented technology

The invention provides a novel battery energy-storage system and a function integration designing method thereof. The system comprises an energy storage unit and an EMS (energy storage monitoring system); the energy storage unit comprises an EB (energy storage battery unit), an BMS (battery management system) and a PCS (power storage current transformer); the EB is connected with the BMS, the BMS is respectively connected with the EB and the PCS, the input end of the EMS is connected with the output end of the BMS, and the PCS and the EMS are communicated with each other. The method comprises an energy storage battery monitoring and analyzing method achieved through the BMS and the PCS and an energy-storage system monitoring and analyzing method achieved through the PCS and the EMS. In the battery energy-storage system function integration design provided by the invention, all large application occasions of electric power systems are covered, the objective is clear, and various requirements and applications are met.

The invention discloses a microgrid system coordination control method which takes a storage battery energy storage system as a main power supply. The conventional inversion products and technology hardly form a microgrid and cannot meet the requirement on stable operation of the microgrid system. The storage battery energy storage system in the microgrid is taken as a main power supply when the microgrid independently works, the microgrid frequency and voltage are kept constant, and a distributed power supply controls the power along with the microgrid voltage and a phase angle; and a microgrid control system controls a bidirectional inverter for energy storage to effectively switch between a parallel control mode and an independent operation mode according to the state of an external power grid. The power supply in the microgrid has the advantages of high robustness, high speed, and capacities of realizing bidirectional flow of electric energy and flexible current control and meeting the requirement on stable operation of the microgrid system.

An electrical energy storage unit and control system, and applications thereof. In an embodiment, the electrical energy storage unit (which may also be referred to as a battery energy storage system (“BESS”)) includes a battery system controller and battery packs. Each battery pack has battery cells, a battery pack controller that monitors the cells, a battery pack cell balancer that adjusts the amount of energy stored in the cells, and a battery pack charger. The battery pack controller operates the battery pack cell balancer and the battery pack charger to control the state-of-charge of the cells. In an embodiment, the cells are lithium ion battery cells.

Disclosed is a comprehensive coordination control method of a wind-solar direct current micro-grid. The wind-solar direct current micro-grid comprises wind driven generator and alternating current (AC) / direct current (DC) / DC converters, photovoltaic array and DC / DC converters, a circuit interrupter, AC / DC load and DC / AC and DC / DC converters, a DC bus, a supercapacitor energy storage system and bi-directional DC / DC module, a storage battery energy storage system and bi-directional DC / DC module, a bi-directional AC / DC converter, a coordination controller, a control network for connecting the coordination controller and the converters and a communication network for connecting the coordination controller and a large power grid power scheduling center, and an operational mode of the wind-solar direct current micro-grid is divided into two categories of a grid-connected mode and an island mode. Stable operation of the wind-solar direct current micro-grid under the grid-connected mode and the island mode is achieved by comprehensively using power scheduling, load scheduling and energy storage device scheduling.

The invention discloses a dynamic power coordination control method for a battery energy storage system. The battery energy storage system comprises a plurality of power converters which supply power to a load and are connected in parallel for operation, and is characterized in that: the power converters connected in parallel for operation are divided into two types, and a master-slave control scheme is adopted, wherein one type comprises only one power converter which adopts a constant voltage constant frequency control mode and is called a master node, and the power converters of the other type adopt a constant power mode with a slight droop characteristic, and serve as slave nodes; generally, a power converter with a high capacity is selected to be the only one master node which is specified by an upper-layer monitoring system, and all the other power converters are the slave nodes; and under a stable state condition, active power and reactive power output by the power converters which serve as the slave nodes are set by a power instruction transmitted by the monitoring system, and the output power of the power converter which serves as the master node is dynamically regulated according to a load condition. The method adopting the master-slave control scheme has the advantages that: on the premise of sufficient power capacity, both the voltage stability and frequency stability of a micro-grid system are easily achieved, anti-load disturbance capability is high, and failure recovery time is short.

The invention relates to a battery energy storage system based power conversion system and a control method thereof. The power conversion system comprises a battery energy storage system, a bidirectional DC / DC (direct-current) converter, a grid-side current transformer, a filter circuit and an isolated voltage transformer. The battery energy storage system is in parallel connection with a direct-current bus of the grid-side current transformer through the bidirectional DC / DC converter; the grid-side current transformer, the filter circuit and the isolated voltage transformer are connected in sequence; and the isolated voltage transformer accesses to a power grid. The control method includes sequentially monitoring the battery energy storage system, the bidirectional DC / DC converter, the grid-side current transformer, the filter circuit and the isolated voltage transformer by a control circuit. Since the battery energy storage system utilizes battery cells connected in series and is in parallel connection with the common direct-current bus through the bidirectional DC / DC converter, circulation among battery packs is avoided, and capacity expansion of the system is facilitated. Further, by the aid of the monitoring control strategy for SOC (super capacitor state of charge) of the battery energy storage system and battery end voltage, excessive charge or discharge state of the battery energy storage system is avoided, service lives of the battery packs are prolonged, and comprehensive service cost is lowered.

The invention relates to a wind power station energy storage capacity control method based on particle swarm optimization. The wind power station energy storage capacity control method includes the steps of taking the interval reference value of the wind power station output power which is adapted to the dispatching cycle of a power grid as a foundation, taking the influence of the wind-abandoning energy of a wind power station and the lost energy of an energy storage system into consideration, taking the lowest costs of the energy storage investment and a wind and power operation system as target functions, establishing a policy model for energy storage capacity optimizing based on a storage battery energy storage system, and then applying the improved particle swarm optimization to solve the functions. By the aid of the wind power station energy storage capacity control method based on the particle swarm optimization, the wind power which is output under effect of the energy storage system can be output smoothly at intervals, so that effective connection between the energy storage system and the existing dispatching operation manner can be realized, and the best economic benefit can be achieved simultaneously.

The invention relates to a battery energy storage system peak clipping and valley filling real-time control method based on load prediction and belongs to the field of power system automatic control. The control method provided by the invention comprises the following steps of: firstly searching similar history daily load data, carrying out expanding short-term load prediction by adopting a linear regression analysis method, building a battery energy storage system peak clipping and valley filling real-time optimization model, solving the battery energy storage system peak clipping and valley filling real-time optimization model by adopting a dynamic programming algorithm, and obtaining the output power of a battery energy storage system at each moment. The control method provided by the invention comprises battery charging and discharging frequency constraint and discharge depth constraint in the real-time optimization model, is used for researching relation between battery life and the charging and discharging frequency and the relation between the battery life and the discharge depth and is beneficial to prolonging the battery life. Minimum load variance is taken as a target function, the peak-to-valley of a load curve can be reduced, the load curve is smoother while constraint conditions are met, and the peak clipping and valley filling application requirement can be met. Local part of the load curve can be smoother by adopting load smoothness constraint.

The invention relates to a method and system for improving reliability of emergency power supplies of a nuclear power plant. At least one path of high-capacity battery energy storage system (fixed energy storage system and / or movable energy storage system) is used to supplement or replace final emergency power supplies of a nuclear power plant. When all existing emergency power supplies of the nuclear power plant fail, the system is started to supply power for equipment in an emergency plant of the nuclear power plant so as to keep discharging waste heat of reactor cores and cooling spent fuel pools of the nuclear power plant, thus ensuring the safety of the nuclear power station. The method and system provided by the invention can be used for resisting against extreme weathers and avoiding common mode failure of the emergency power supplies in the extreme weathers, can strength the reliability of the emergency power supplies of the nuclear power plant and can at least reduce the melting probability of reactor cores by 21.6%, thereby improving the integral nuclear safety level of the nuclear power plant.

The invention discloses a grid-connected non-networking micro-grid system and a control protection method thereof. On the premise of basically not changing the structure of the original power distribution system, multiple types of distributed power sources, such as wind power generation system, photovoltaic power generation system, cell accumulation system and the like, are connected into a common power grid along with user loads through AC buses, and reasonable load layout and active energy management are utilized to implement grid-connected non-networking of the micro-grid system. By using the structural design and the active energy management of the micro-grid central control unit, the new energy power generation system can be completely self-sufficient, and does not reversely transmit power to the common power grid, thereby avoiding impacting the normal power supply of the common power grid; and meanwhile, by the aid of the common power grid, the user loads have higher power supply reliability and electric power quality.

In one embodiment, a current-fed modular multilevel dual active-bridge DC-DC converter suitable for medium voltage direct current (MVDC) grid or high voltage direct current (HVDC) grid integration is described. The DAB modular converter and the current-fed DAB converter are soft-switched modular multilevel dual-active-bridge (DAB) converters having DC fault ride-through capability. In an additional embodiment a voltage-fed isolated modular dual active-bridge DC-DC converter for medium voltage direct current (MVDC) or high voltage direct current (HVDC) grids or systems is described. In specific embodiments, the converters may be coupled to a battery energy storage system (BESS), wherein the BESS comprises split-battery units and the interface of the isolated DC-DC converter connects the split-battery units to the MVDC or HVDC system. The converters can be implemented in single-phase or poly-phase configurations and can be controlled to maintain a desired DC output current under both normal and DC grid fault condition.

The invention relates to a method for improving wind power tracking capability on planned output by an energy storage system. The method is characterized in that: charging and discharging of a cell energy storage system are effectively controlled, so that it is realized that wind storage combination output P out tracks wind power planned output in a designated and allowed error bandwidth. Comparison is carried out on a real-time wind power PWG and a currently planned target output power, namely a wind power prediction power PFC; if a difference value exceeds the allowed error bandwidth, the cell energy storage system is controlled to absorb or release a portion of power Pbess, so that an error between the wind power PWG and the prediction power PFC is reduced and tracking of wind storage combination output on the wind power planned output can be realized. Meanwhile, the method provided in the invention enables optimization control on a state of charge (SOC) of the cell energy storage system to be considered; and continuity and reliability of stable operation of a wind storage combination application system can be ensured by dividing SOC areas and reasonably dispatching charging and discharging electric quantities of the stored energy of the cell.

An electrical energy storage unit and control system, and applications thereof. In an embodiment, the electrical energy storage unit (which may also be referred to as a battery energy storage system (“BESS”) includes a battery system controller and battery packs. Each battery pack has battery cells, a battery pack controller that monitors the cells, a battery pack cell balancer that adjusts the amount of energy stored in the cells, and a battery pack charger. The battery pack controller operates the battery pack cell balancer and the battery pack charger to control the state-of-charge of the cells. In an embodiment, the cells are lithium ion battery cells.

The invention relates to a micro-grid system, and in particular relates to a micro-grid system for ships. The micro-grid system for the ships comprises a solar photovoltaic power generation system, a wind power generation system, a storage battery energy storage system, an emergency diesel generator, a load, a direct current bus and an alternative current bus, wherein the direct current bus and the alternative current bus are connected together through a bidirectional converter; the direct current bus is connected with the solar photovoltaic power generation system and the storage battery energy storage system; the alternative current bus is respectively connected with the wind power generation system, the emergency diesel generator and the load; and the system is connected with a medium voltage main power grid in the ship through an interconnection switch and a transformer at side where the alternative current bus is positioned. The defect that the new energy distributed type power generation cannot be directly used in a ship power system is overcome, a new offshore energy resource is sufficiently utilized, and the energy conservation and the emission reduction in the field of ocean transportation are realized.

The invention discloses a control method for stabilizing the fluctuation of wind power by an energy storage system. Data acquisition equipment acquires wind power data, wind storage synthesized output force data and state of charge (SOC) data, and inputs the data into a stabilizing control module; in the stabilizing control module, a maximum wind farm active power change limit value Plimit' per minute is used as a control target, a control principle that the control target is met and the energy storage system of a battery has relatively high charging / discharging capacity is adopted, and the input data are calculated according to a stabilizing control strategy; the wind power data PWG(k) is subtracted from the wind storage synthesized output force Pout(k-1) to obtain a different value deltaP(k); the obtained different value deltaP(k) is compared with the wind minute-level active power change limit value Plimit' and the maximum output force limit value maxPbess of the energy storage system of the battery so as to judge whether the energy storage system of the battery participates in regulation and control over the wind power output force; when deltaP(k) is greater than the Plimit' and less than the maxPbess, a control instruction for controlling the energy storage system of the battery is output; a battery management system (BMS) controls the output force of the energy storage system of the battery; therefore, the fluctuation of the wind power is stabilized, and the negative effects of the wind power on a power grid is reduced.

The invention discloses an energy-storage type alternating current and direct current mixed micro-grid and a control method thereof. The energy-storage type alternating current and direct current mixed micro-grid comprises an alternating current micro-grid, a direct current micro-grid, a battery energy-storage system and an energy management system EMS, which are connected with an external grid control center. The control method of the energy-storage type alternating current and direct current mixed micro-grid comprises the following steps of initializing the EMS to acquire information data of the alternating current micro-grid, the direct current micro-grid and the battery energy-storage system; acquiring information data of an external public grid in real time; regulating and controlling the alternating current micro-grid, the direct current micro-grid and the battery energy-storage system according to the acquired data. The energy-storage type alternating current and direct current mixed micro-grid and the control method thereof have the advantages that the energy utilization efficiency can be improved, the size of a transformer can be reduced, networking and controlling are more flexible, the cost is reduced, and the power supply reliability of the whole system is improved.

The invention relates to a battery power control method for types of high-capacity megawatt battery energy storage power stations, which comprises the following steps of: A, reading data; B, determining a total command value of each battery energy storage system by using a wavelet transform controller module; C, calculating battery power command values of each energy storage subunit by using a power allocation controller module; D, aggregating the battery power command values of each energy storage subunit by using a power aggregation module; and E, outputting the data. In the method, cooperative control over battery power in the types of high-capacity megawatt battery energy storage power stations based on lithium ions, flows, sodium-sulphur and the like is finished by an industrial personal computer and a communication platform, real-time effective control over the types of high-capacity megawatt battery energy storage power stations can be realized, and the aims of improving the utilization efficiency of energy storage batteries of different types and prolonging the service life of each energy storage battery are fulfilled according to the characteristics of the batteries of different types that lithium ion batteries, sodium-sulphur batteries and flow batteries serve as low frequency, intermediate frequency and high frequency components in current required total power respectively and the like.

The invention relates to a real-time on-line estimation method for the internal resistance of a secondary battery, belonging to the technical field of secondary battery energy storage system control. The real-time on-line estimation method for the internal resistance of a secondary battery only needs to provide the terminal voltage and the load current of the battery without adding other auxiliary hardware circuits. The real-time on-line estimation method comprises the following steps of: constructing a state equation and an observation equation required for an algorithm by using the working principle of an extended Kalman filter based on an equivalent circuit model of a standard battery, taking the open-circuit voltage (VOC), the ohmic resistance (RO), the polarization resistance (RP) and the polarization current (IP) of the battery as estimated quantities, and taking the real-time measurements of the terminal voltage (VL) and the load current (IL) and a time interval delta t between two times of sampling as known quantities; and selecting a process excitation noise covariance and a measurement noise covariance according to the accuracy of a transducer, performing updating through iteration, and further estimating the ohmic resistance and the polarization resistance of the measured secondary battery in real time. Compared with the traditional resistance testing method, the real-time on-line estimation method has the advantages of real-time on-line estimation and good stability, and no hard testing circuit is additionally required.

The invention discloses a layered equalizing circuit system based on a series battery stack and a hybrid control method, and belongs to the technical field of battery energy storage systems. A bottom layer of the architecture adopts an adjacent cell-cell (C2C) structure, and is divided into different battery packs. A top layer adopts a transformer coupled multi-directional multi-port converter, and bidirectional energy flow among arbitrary battery packs of the bottom layer is realized. The layered architecture can reduce the amount of equalizing circuits working simultaneously, so that the repeated charging and discharging problem of the batteries in the equalizing process is avoided, and the health status of the batteries is improved. According to the hybrid control method, during the standing of the batteries, the equalizing current required for each battery cell is obtained by calculating SOC, so that an equalizing system is controlled; when the batteries work, each equalizing circuit is controlled by calculating SOC change rate, so that a potential unequalizing tendency is forecasted in advance and is corrected, and real-time equalizing for each battery is guaranteed. Moreover, according to the layered architecture and the control method, the rated current required for the equalizing circuit can be reduced, so that the system cost is reduced, and the energy loss is reduced.

The invention provides a ship multi-type energy source management system and an energy source management method. The ship multi-type energy source management system comprises a monitoring and energy source management master module, a diesel power generation system, a wind power generation system, a photovoltaic power generation system, a wave energy power generation system, a storage battery energy storage system, a shore power system, a direct current bus bar and a plurality of paths of power transmission systems. The ship multi-type energy source management system and the energy source management method have the advantages that the ship multi-type energy source management system provided by the invention fills the technological blank of integrating various types of green energy source power generation into ship heat energy power generation systems; the energy conservation and emission reduction are met; the global warming is responded; the greenhouse gas emission is controlled; the atmospheric environment is protected and the sustainable development of low-carbon economy is promoted.

The invention discloses a capacity optimization and configuration method of an individual micro-grid storage battery energy storage system. The capacity optimization and configuration method comprises the following steps: firstly, determining the installed capacity of wind power generation and photovoltaic power generation in the micro-grid and the size of load connected to the micro-grid system, and inputting each reference data required for calculation; making sure whether a diesel engine serving as a backup power supply is available or not and how large the capacity of the diesel engine power generation is according to the actual situation of the micro-grid; determining the relevant constraint conditions and each datum of the selected energy storage battery as well as setting indexes of the power shortage rate of the load power supply for the micro-grid; calculating the total power of wind and light generation according to the detailed resource data and the load power requirement in the same period of time so as to obtain the power balance; calculating the required energy storage capacity according to power balance of each period of time to obtain the power shortage which is possibly generated in each period of time and cannot be compensated by the storage battery; and calculating the total power shortage rate in the period of time required by the system so as to obtain the total capacity of the storage battery to meet the requirement. According to the invention, the reasonable energy storage capacity meeting the system running requirement can be obtained.

The invention discloses a battery state-of-health (SOH) optimization control method for a modular multilevel battery energy storage system, comprising the following steps: determining the relative SOH of all battery packs by measuring the rate of change in state of charge of the battery packs; presetting a state-of-charge change curve of each sub module battery pack; and balancing the SOH of all the battery packs in the charge / discharge state of the energy storage system according to the proportion of real-time input / output power assigned to different battery packs in the total power, and finally narrowing the difference between the battery packs in SOH. When the performance of an individual battery pack decreases, the discharge ratio and the discharge depth of the battery pack can be reduced by controlling corresponding modules of an MMC, and therefore, the battery pack is protected. Moreover, the thermal management requirement of the modular multilevel battery energy storage system is lowered.

A battery energy storage system is disclosed, the battery energy storage system comprising a rechargeable battery assembly for storing and providing energy and a protection system including an arc flash protection device to protect against risks due to arc flashes. The arc flash protection device comprises an overcurrent protection unit which detects overcurrent conditions indicating arc flash conditions in case of a low impedance of the battery assembly and an undervoltage protection unit which detects undervoltage conditions indicating arc flash conditions in case of a low impedance of the battery assembly, wherein upon detecting the overcurrent conditions and / or the undervoltage conditions for a predetermined minimum time period, the arc flash protection device initiates protective measures to prevent further operation of the battery assembly. An energy conversion system comprising such a battery energy storage system, which can be used for stationary and mobile energy supply or distribution applications, is also disclosed.

The invention provides a method and a system for controlling a battery energy storage power station of supporting black start of a light-preserved power generation system. The method comprises steps of obtaining power station data including power grid operation states, load types, photovoltaic output values, load power values and energy storage current transformer charged states; determining whether or not a power grid has a fault according to the power grid operation state; when the power grid has a fault, calculating the number of energy storage current transformers for charge-discharge power distribution according to the photovoltaic output values and load power values and using the current transformer power optimization principle; and establishing a light-preserved combined power generation output optimal objective function, and determining the power of each energy storage current transformer for charge-discharge power distribution according to the load power values, the photovoltaic output values and the charged states of the energy storage current transformers for charge-discharge power distribution. The invention achieves black start of a power grid through a battery energy storage system combined with a photovoltaic electric field when the power grid has a fault, and achieves control of stable operation of the power grid.

The invention provides a light-storage type EV (electric vehicle) charging and converting station, belonging to the field of power supply systems. The station is used for solving the problems caused by taking an alternating current power grid as a power supply source in the existing EV charging and converting station. The light-storage type EV charging and converting station comprises a photovoltaic generating system, a storage battery energy accumulation system, an EV charging station and a station-used load, wherein the photovoltaic generating system comprises a solar battery assembly, a grid connected inverter and a photovoltaic power supply management system, and is suspended on a power supply bus of the photovoltaic system; the storage battery energy accumulation system comprises a storage battery pack, a battery management system and a dual-direction inverter, and is suspended on a power supply bus of the load; the EV charging and converting station and the station-used load are suspended on the power supply load of the load; and the power supply bus of the photovoltaic system and the power supply bus of the load are respectively connected with a 380V bus in the alternating current power grid, and are connected by a photovoltaic access breaker.

The invention, belonging to the field of dispatching and management of a distribution network, provides a method and system for switching a microgrid between an island mode and a grid connected mode. When an external electric network has a fault, distributed power in a microgrid system is cut off, a grid connected contact breaker of the microgrid system and the external electric network is opened, a voltage and a frequency of the microgrid system are regenerated by a main power switching control mode in the microgrid system, and the microgrid system works independently; and when the external electric network returns to normal, if the electric network side voltage of the grid connected contact breaker is monitored to be normal and is lasted for a certain time, operations of a fan, a photovoltaic power generation system and an energy storage system of a storage battery are stopped, the grid connected contact breaker of the microgrid system is closed, a load is powered with the external electric network, the devices such as the fan and the like are reconnected to the grid for operation, so that a stable operation of the microgrid system in a transient state process of switching between the island mode and the grid connected mode is satisfied, the transient time is shortened, and the requirements of the microgrid system in safety, reliability and quick response are satisfied. The method and system have the characteristics of quickness, stability and reliability.

The invention provides a control method of a cell energy storage system inhibiting renewable energy output power fluctuation. The control method is characterized in that: based on a low pass filtering principle, through a first order Butterworth filter, a renewable energy output power value is subjected to filtering, a renewable energy output power object value is obtained, by utilizing charge and discharge control of the cell energy storage system, a difference between the renewable energy output power object value and a renewable energy output power measured value is compensated, and a purpose of inhibiting the renewable energy output power fluctuation is achieved. According to the invention, based on a basic filtering principle, by utilizing a good renewable energy output power inhibition effect and adding of an SOC (state of charge) feedback link, over charge and over discharge of a cell are avoided, innovation is carried out, when adding the SOC feedback link, through adjusting a size of a filtering time constant, an output power of the energy storage system is changed indirectly, thus when inhibiting the inhibiting the renewable energy output power fluctuation, the over charge and over discharge of the cell are effectively avoided, stable operation of the cell energy storage system is maintained, and a service life of the cell is prolonged.

The invention discloses a photovoltaic-energy storage joint power station optimal operation method considering a typical scene, which belongs to the field of photovoltaic-energy storage joint power station optimal configuration. A typical scene partitioning method based on an SOM clustering algorithm analyzes different typical operation scenes of the photovoltaic-energy storage joint power station; then, in consideration of generating profits, rewarding and punishment assessment profits and energy storage peak shaving and valley filling profits, a photovoltaic-energy storage joint power station typical scene profit optimization model is built; and finally, the model is used to analyze and discuss a profit optimal operation mode under the typical operation scene of the photovoltaic-energy storage joint power station. Example analysis shows that by using the typical scene analysis method and the profit optimization model, a battery energy storage system of the photovoltaic-energy storage joint power station can be reasonably optimized and configured, a correction operation mode is built, and the photovoltaic-energy storage joint power station can acquire the optimal economic profits.

The invention discloses a method for controlling the frequency modulation of a micro-grid battery energy storage system based on fuzzy control, and belongs to the technical field of electric power system micro-grids. On the basis of the conventional proportion integration differentiation (PID) control, fuzzy control and an implementation mode thereof are introduced into the method, and the method comprises important components such as fuzzification, fuzzy rules, fuzzy reasoning, defuzzification, PID control and the like. According to the method, the micro-grid frequency deviation and the micro-grid frequency change rate are fuzzified into input of a fuzzy controller, PID control parameters of active power output control are output according to a fuzzy control rule, and an active power output reference value Pref of the battery energy storage system is finally output to control the active power output of the micro-grid battery energy storage system. Compared with the conventional PID control, the method has very strong adaptability to the switching of micro-grid parallel network / isolated network operational modes and to the nonlinearity and the time variability of electric network operational parameters, has a good dynamic response characteristic, and effectively improves the active power control accuracy of the battery energy storage system and the frequency stability of the micro-grid.

The invention provides an in-phase SOC (state of charge) balance control method applying to an H bridge cascaded battery energy storage system. The method includes collecting SOC information of energy storage batteries and charging and discharging states, namely collecting the SOC information of each H bridge power unit energy storage battery and the charging and discharging states of the system at the moment; adjusting amplitude of a carrier triangular plate, namely adjusting the amplitude of the carrier triangular plate respectively according to different states of a PCS (power conversion system). By taking a high-capacity battery energy storage H bridge cascaded power conversion system as an object, the objective of controlling a modulation ratio to realize in-phase energy storage battery SOC power balance is achieved by collecting states of charge of the batteries. By the in-phase SOC balance control method, influences on phase output voltage of changes of the stages of charge of in-phase batteries of the energy storage power conversion system can be eliminated, good adjusting characteristics especially for unstable voltage of a battery platform are realized.