Energy storage inverter, also known as bi-directional energy storage inverter, PCS (Power Conversion System), is used in grid-connected energy storage and micro-grid energy storage and other AC coupling energy storage systems, connecting the battery bank and the grid (or load), is a device to achieve bi-directional conversion of electrical energy. It can reverse the DC power from the battery into AC power and transmit it to the grid or the AC load; it can also rectify the AC power into DC power and charge the battery.
Energy storage inverter (PCS) consists of power, control, protection, monitoring and other software and hardware electric components. Single-phase PCS is usually composed of a two-way DC-DC boost device and DC/AC AC/DC inverter; the DC side is usually 48Vdc, the AC side 220Vac. Three-phase PCS is divided into two types; small power three-phase PCS is composed of a two-way DC-DC boost device and DC/AC AC/DC inverter, high-power three-phase PCS is composed of DC/AC/DC inverter. AC-DC inverter first stage device. Energy storage inverters are divided into three types: high-frequency isolation, industrial frequency isolation and no isolation. Single-phase and low-power three-phase PCS below 20kW generally adopt high-frequency isolation, 50kW to 250kW generally adopt industrial frequency isolation, and above 500kW generally adopt no isolation.
Important technical parameters of energy storage inverters: Due to different applications, energy storage inverters’ functions and technical parameters vary greatly. When choosing, attention should be paid to system voltage, power factor, peak power, conversion efficiency, switching time, etc. The choice of these parameters has a significant impact on the function of the energy storage system.
01-System voltage
It is the voltage of the battery bank, the input voltage of the energy storage inverter. Energy storage inverters of different technologies, the system voltage varies greatly, single-phase two-stage structure of the energy storage inverter in about 50V, the three-phase two-stage structure of the energy storage inverter between 150V-550V. The three-phase energy storage inverter with an IFT isolation transformer is between 500V-800V, and the three-phase energy storage inverter without an IFT isolation transformer is between 600V-900V.
02-Power Factor
When the energy storage inverter is operating normally, the power factor should be greater than 0.99. When the system is involved in power factor regulation, the power factor range should be as comprehensive as possible.
03-Switching time
Energy storage inverter has two kinds of switching time; one is charging and discharging switching, large energy storage countercurrent should be able to switch the operating state quickly, usually required between 90% rated power grid-connected charging state and 90% rated power grid-connected discharging state, the switching time is not more than 200ms, the second is applied to the switching of grid-connected mode and off-grid mode, the switching time is not more than 100ms.
The energy storage inverter mainly has two working modes: on-grid and off-grid. Grid-connected mode to achieve two-way energy conversion between the battery bank and the grid. It has the characteristics of the grid-connected inverter, such as anti-islanding, automatic tracking of grid voltage phase and frequency, low-voltage ride-through, etc. According to the requirements of grid dispatch or local control, PCS converts AC power from the grid into DC power to charge the battery bank during grid load low period, with battery charging and discharging management function; during grid load peak period, it reverses DC power from battery bank into AC power to feedback to the public grid; during grid load peak period, it converts DC power from battery bank into AC power to charge the battery bank. When the power quality is not good, it feeds or absorbs active power to the grid and provides reactive power compensation. Off-grid mode, also known as off-grid operation, means that the PCS can be disconnected from the primary grid according to the actual needs and under the condition of meeting the set requirements, providing AC power to the local load to meet the power quality requirements of the grid.
Different inverters use different protocols. The storage battery in a home energy storage system needs to support the protocol of the corresponding brand of the inverter to be used in combination. SPbatt battery Compatible witg below inverter brands:
Deye inverter, Megarevo inverter, Goodwe inverter, Voltron inverter, Growatt inverter, Eastups inverter, Sofar solar inverter, Star inverter, Sunglow inverters, Tbear inverter, Chint inverter, Samil power inverter, JFY inverter, Omnik solar inverter