現(xiàn)代儲能系統(tǒng)中使用的鋰離子電池確實可以提供卓越的性能,但對每個電池單元進行密切監(jiān)控至關(guān)重要,以確保其正確充電并避免不平衡、過度充電、深度放電或過熱。為此,需要為每個電池單元或電池陣列提供獨立、隔離的電源電壓控制電路。
對于標稱電壓高達48V的電池陣列,可以使用標準工業(yè)DC/DC電源轉(zhuǎn)換器模塊,這些模塊提供500V或1600V的隔離屏障。然而,對于更高功率的系統(tǒng),尤其是那些連接到交流電源并提供數(shù)百千瓦時甚至數(shù)兆瓦時儲能容量的系統(tǒng),電池陣列的電壓可以達到600-800V。這種情況下,需要具有更高隔離屏障的解決方案。
為了增強抗噪能力,P-DUKE提供了一系列擁有5kV隔離屏障的醫(yī)療級電源轉(zhuǎn)換器,超過了4kV的項目需求。在該項目中,選擇了MPD30-24S12模塊,該模塊能夠從公共24V直流總線產(chǎn)生必要的12V/30W電源電壓。
通常的工業(yè)級30W DC/DC電源轉(zhuǎn)換器的輸入輸出電容高達1500pF。如果并聯(lián)多達200個轉(zhuǎn)換器,電池單元(通過充電器連接到交流電網(wǎng))和24V總線之間的總電容可能達到300nF,這會導致超過20mA的交流漏電流。而漏電流超過10mA可能會引發(fā)嚴重的觸電風險和事故。
然而,MPD30-24S12的輸入輸出電容僅為20pF,即使并聯(lián)200個轉(zhuǎn)換器,總電容也只有4nF,漏電流低于1mA。這種極低的電容還避免了瞬態(tài)或任何噪聲通過轉(zhuǎn)換器耦合到中央電池管理系統(tǒng)的敏感通訊信號中。因此,這種解決方案有效解決了4kV隔離和低漏電流的要求。
在整個安裝過程中,通信系統(tǒng)的中央BMS控制器使用WiFi路由器,并通過以太網(wǎng)由25W的53V電源供電。根據(jù)安裝,電源電壓可以由230Vac主電源或內(nèi)部24Vdc總線提供。對于230Vac電源,可以使用TSD30系列轉(zhuǎn)換器。此外,該系列還提供DIN導軌式版本,便于安裝在控制器機架中。
The lithium-ion batteries used in modern energy storage systems can indeed provide excellent performance, but close monitoring of each battery unit is crucial to ensure proper charging and avoid imbalance, overcharging, deep discharge, or overheating. For this, it is necessary to provide independent and isolated power supply voltage control circuits for each battery unit or battery array.
For battery arrays with a nominal voltage of up to 48V, standard industrial DC/DC power converter modules can be used, which provide isolation barriers of 500V or 1600V. However, for higher power systems, especially those connected to AC power and providing energy storage capacity of hundreds or even megawatt hours, the voltage of the battery array can reach 600-800V. In this case, a solution with higher isolation barriers is needed.
In order to enhance noise resistance, P-DUKE offers a range of medical grade power converters with 5kV isolation barriers, exceeding the project requirements of 4kV. In this project, the MPD30-24S12 module was selected, which can generate the necessary 12V/30W power voltage from the common 24V DC bus.
The input and output capacitance of a typical industrial grade 30W DC/DC power converter can reach up to 1500pF. If up to 200 converters are connected in parallel, the total capacitance between the battery unit (connected to the AC grid through a charger) and the 24V bus may reach 300nF, which can result in AC leakage currents exceeding 20mA. Leakage current exceeding 10mA may cause serious electric shock risks and accidents.
However, The input and output capacitance of MPD30-24S12 is only 20pF, even if 200 converters are connected in parallel, the total capacitance is only 4nF, and the leakage current is less than 1mA. This extremely low capacitance also avoids transient or any noise coupling into the sensitive communication signal of the central battery management system through the converter. Therefore, this solution effectively addresses the requirements of 4kV isolation and low leakage current.
Throughout the installation process, the central BMS controller of the communication system uses a WiFi router and is powered by a 25W 53V power supply via Ethernet. According to the final installation, the power supply voltage can be provided by a 230Vac main power supply or an internal 24Vdc bus. For a 230Vac power supply, the TSD30 series converter can be used. In addition, the series also offers a DIN rail version for easy installation in the controller rack.