The principle of energy storage converter PCS concept and how fast selection

　　Author ：Iflowpower – Portable Power Station Supplier

1 Meaning battery energy storage of energy storage converters As one of the important forms of large-scale energy storage systems, with multiple uses such as peak, fill valley, frequency modulation, correction, accident alternative. Compared with the conventional power supply, the large-scale energy storage power station can adapt to the rapid change in the load, and play an important use of the safety and stable operation of the power system, the power supply and reliability of the power grid can also optimize the power structure, and achieve green environmental protection. The overall energy saving reduction of the power system, improve overall economic benefits.

In the powerconversionsystem, referred to as a PCS, an electrochemical energy storage system, a device connected between the battery system and the grid (and / or load), can control the charging and discharge process of the battery, The conversion of the DC, can be powered directly to the AC load in the case of no power grid. PCS consists of DC / AC two-way converter, control unit, and the like. The PCS controller receives the background control instruction by communication, charging or discharging the battery according to the symbol of the power command and the size of the power instruction, and the adjustment of the power grid has effort and reactive power.

At the same time, PCS can obtain battery pack status information through the CAN interface to BMS, dry contact transmission, etc., which can realize protection of the battery to ensure safety of the battery. 2 Executive Standard "Energy Storage Translucent Detection Technical Regulations" "Battery Energy Storage Energy Converter Technical Specification" GB / T14549 Electrical Power Quality Power Grid Harmonic GB / T15543 Power Quality Three-Phase Voltage Unbalance GB / T15945 Power Quality Power System Frequency Deviation GB / T12325 Power Quality Power Supply Voltage Deviation 3 Product Description 3.

1 Working Principle Energy Bifunctional Translucent (PCS) is the converter device for the operation of the / DC side controlled four-quadrants, and achieves communication between electric energy. Conversion. PCS can realize the two-way energy transfer between the DC battery and the AC grid of the battery energy storage system, and the charging and discharging management of the battery system is implemented by the control strategy, the tracking of the network side load power, and the control of the battery energy storage system.

Control of the network side voltage in the network operation mode. 3.2 Important features of the functional feature storage converter are grid network conditions, and the energy storage system performs constant power or constant current control according to the microcontrol instruction, charging or discharging the battery, while smoothing the output of volatility power such as wind power, solar energy Under micro-network conditions, the energy storage system is supplied as the main power supply of micro-network voltage and frequency support (V / F control), and the load is based on this voltage and frequency.

PCS adopts double closed loop control and SPWM pulse modulation method, which can accurately adjust the output voltage, frequency, active and reactive power. 3.3 Basic control function and network constant power charge, discharge control and network constant voltage limit flow charging network V / F control reactive power adjustment control pane-network smooth switch control anti-canal protection function and island detection mode switching function fault crossing Control function 3.

4 Basic protection function: battery polarity reverse protection DC overvoltage protection DC overcurrent protection network side / undervoltage protection network side overflow protection network side / undervert protection IGBT module overcurrent protection IGBT module over temperature protection Transformer / reactor over temperature protection lightning protection non-planned island protection 3.5 Product advantage unique mode switch smoothing control technology, guaranteeing grid-connected networks to switch without impact, ensuring reliable running. To ensure that the converter is connected to the network, it will increase or decrease the powerful power, reactive power; stabilize the load voltage at independent runtime.

Charging, discharging integrated design, realizing energy bidirectional flow of AC systems and DC systems; efficient vector control algorithms, achieving active, reactive decoupling control; power factor can be adjusted, can be free in full capacity, Realizing reactive power compensation; under the scheduling of MEMS (micrometer energy management system), actively participate in the peak of the grid, effectively alleviate the pressure of the large grid; support the grid operation, run away from the network; Smooth seamless switching; support micrometer operation, can supply stable voltage and frequency support for microfrides; the initiative is combined with passive island detection methods to meet UL1741 standards; perfect relay protection functions, effectively prevent the abnormal inverter Damage; support a variety of energy storage batteries, different models only the software of the controller is different; supply CAN, 485, can communicate with the battery management system (BMS), upper monitoring system; multiple PCS can implement multi-machine parallel operation; support Short-term short-circuit operation mode on the AC side; supports self-playback function; high reliability cabinet design, meets different operational areas; main power circuit uses high reliability power modules; 5 application storage energy converters is widely used in power systems, tracks Traffic, special, oil machinery, new energy vehicles, wind power, solar photovoltaic and other fields, in the grid peak, smooth new energy fluctuations, energy recovery and other applications, energy recovery, etc., the power supply frequency is active, improve power supply Power Quality. It can be used in distributed power generation systems such as wind energy, solar energy to ensure equalization and persistence of distributed power supply, effectively improve their electrical energy output quality, and improve access grid.

Can be used in power system stability, can respond to the fluctuation of the load by fast power storage, absorb excess energy or supplementate energy, achieve high-power dynamic adjustment, well adaptation of frequency adjustment and voltage power factor correction, thus Improve the stability of system operation. Can be used as an emergency power supply, supply electrical energy to users during large grid or other power supply, improve power supply reliability. Can be used in grid peaks, can alleviate the contradiction between supply and demand side, reduce investment of power generation equipment, improve the use of power equipment, reduce line loss.

Can be used in microphrome, as the main power supply, supply microconfront voltage and frequency support, make wind power and photovoltaic in micro-network to supply regional load. Can be used in various types of energy storage components, realizing the flexible interface of the energy storage and grid, can meet independent or grid operation requirements. 6 Quick Selection Calculation Methods The storage energy converter configuration generally determines the actual load and distributed power generation energy capacity in the micrometer.

Load is divided into importance (computer room, office, monitoring and other load), non-importance load (air conditioning, lighting, boiler, door, load data), load data is generally measured, generally measured working day, holiday data, And the data comprehensive analysis of the typical time of the four seasons. 6.1 The energy storage converter capacity matches the energy storage capacity configuration is 1.

2 times the load capacity, such as the importance load of 200KW, it is recommended to configure 250 kW energy storage converter. Other loads are required to run network, then the corresponding new reservoir power ratio. 6.

2 Energy storage converter transformer variable ratio storage converter transformer is determined by the DC voltage input range (ie battery voltage range), the calculation method is as follows: Transformer ratio = UL (battery lowest voltage) / 1.414. If the voltage range of the ferric lithium ion battery is 360 ~ 480VDC, 360 / 1.

414 = 254, the transformer ratio can be determined as 200. If the selected transformer is selected, the lowest voltage of the battery needs to reach 540V to access 400V grid. 6.

3 Energy storage converter additional function Configure the self-playing function (S): The energy storage converter does not require other devices to achieve seamless and off-network switching, and the energy storage converter is made by the grid switch. And the network is transferred to the network running instructions to turn the closing gate, and the instruction is issued by the grid. The connection is issued to enable the gateway (the closing condition is judged by the converter, the uncomfortable closing); Super Capacitor Charger function (C): When the energy storage converter is connected to the supercapacitor product, the 0 voltage can be started to charge the supercapacitor, and charge and discharge when the supercapacitor voltage reaches the operating voltage, replacing the traditional charging machine.

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