Analysis of Electrostatic and Surge Protection Technology for Energy Storage Converters
一、Energy storage converter（PCS）
The Power Conversion System (PCS), also known as the power conversion system, is the core link for achieving bidirectional energy conversion in the energy storage system. A complete electrochemical energy storage system mainly consists of battery packs, battery management systems (BMS), energy management systems (EMS), power conversion systems (PCS), and other electrical equipment, responsible for the bidirectional conversion of alternating current and direct current between the energy storage unit and the power grid/load.
It includes the following core links：
|
变流器类型 |
核心环节特点 |
|
整流器（AC/DC） |
以整流桥（二极管 / SCR/IGBT）为核心，侧重输入滤波和功率因数校正（PFC）。 |
|
逆变器（DC/AC） |
以全桥 IGBT/PWM 调制为核心，侧重输出滤波和并网同步控制（如锁相环 PLL）。 |
|
斩波器（DC/DC） |
采用 Buck/Boost（降压 / 升压） 等拓扑，侧重高频开关和效率优化（如软开关技术）。 |
|
变频器（AC/AC） |
包含 “整流 + 直流环节 + 逆变” 三级结构，侧重电机调速控制（如矢量控制、V/F 控制）。 |
二、The electrostatic surge sensitive node of the energy storage converter
Based on the concept of modular design, the typical block diagram of the energy storage converter is as follows：
Analysis of Sensitive Nodes：
|
分类 |
敏感节点 |
典型电压范围 |
浪涌标准对应 |
|
电网接口 |
断路器 / 变压器端子 |
线电压 380V AC |
IEC 61000-4-5（线-地 ±4kV，线-线 ±2kV） |
|
滤波电路 |
电感 / 电容连接点 |
交流侧电压（如 PCC 点） |
IEC 61000-4-4（EFT电快速瞬变脉冲群±4kV） |
|
功率变换单元 |
IGBT 栅极、直流母线 |
直流母线800V DC |
IEC 61000-4-2（ESD±6kV，栅极静电防护） |
|
测量单元 |
电压 / 电流传感器信号端 |
模拟信号±10V |
IEC 61000-4-5（信号端口±1kV浪涌） |
|
DC链路 |
支撑电容两端（直流母线） |
直流母线浪涌> 1.5倍额定电压 |
UL 1741（直流侧绝缘耐压≥1.5 倍额定 + 1000V） |
|
DC/DC 转换器 |
输入 / 输出接口、开关器件 |
输入800V DC |
IEC 61000-4-5（双向浪涌测试） |
|
电池组（BMS） |
CAN 接口、电压检测端 |
电池单体3.7V |
IEC 61000-4-2（CAN 接口 ESD接触放电±8kV，空气放电±15kV） |
|
控制单元 |
电源接口（5V/3.3V） |
电源浪涌≥6V（5V系统） |
IEC 61000-4-4（EFT±2kV信号端口） |
|
辅助电源 |
输入 / 输出端 |
输入（220V AC，浪涌 4kV）、输出（24V DC，浪涌 > 36V） |
IEC 61000-4-5（电源端口 ±4kV 浪涌） |
|
通信接口 |
CAN 差分线、以太网 RJ45 |
CAN总线±5V、RJ45 |
IEC 61000-4-5（RJ45 接口 ±6kV浪涌） |
三、Full-chain surge protection solution and selection of Thunderbolt electronic components
Based on the principle of lightning strike risk assessment and in combination with the characteristics of each module of the converter, the following protection schemes are recommended：
1. Dc side protection（DC48V）
l First-level discharge：Leiditech Electronics recommends connecting a ceramic gas discharge tube in parallel between GND and PE to provide an efficient discharge path for inrush current；
l Secondary precise clamping：Leiditech Electronics uses TVS devices with a voltage accuracy of ±5% and a response time of less than 1ns (such as SM8S58CA) to clamp the 8/20μs surge peak to ≤93.6V (typical value), protecting the back-end MCU and sensors. Supports multi-power level selection ranging from 400W (indoor low power) to 15kW (outdoor high power)；
l Post-level fine protection：
By series connection of low internal resistance PMOS (such as LM5D50P10, RDS (ON)<28mΩ) for polarity reverse connection, the power loss is reduced by 60% compared with traditional diodes, making it suitable for high-power systems above 20A；
A low forward voltage drop (VF) Schottky diode is connected in parallel near the chip end to suppress negative voltage surges；
Special protection for the battery end: 4.5V TVS (SMAJ4.5A) is adopted, with leakage current < 1μA, to prevent self-discharge of lithium batteries。
The power interface is DC 3.3V/5V
According to the environment where the power supply is located, Leimao Electronics suggests choosing ESD/TVS devices with appropriate protection current, meeting IEC61000-4-2, level 4, contact discharge 8KV, air discharge 15KV. To meet the IEC61000-4-5 surge high-level test requirements, high-power SMC devices should be selected. Please refer to the recommended table at the end of the text。
2. Grid connection protection for AC side of power grid interface (220V/380V AC)
l Differential mode/common mode surge suppression：
Leiditech Electronics adopts the combined scheme of MOV (14D471K/20D471K/25D471K) and GDT (2R600-8L), meeting the test grades of 4kV (indoor) to 8kV (outdoor) of IEC 61000-4-5；
The MOV nominal voltage is 470V, matching the AC network cable voltage, and the GDT inrush current is 10kA, achieving large energy discharge。
3. Refined protection of the control system
CAN bus protection
Leimao Electronics selects semiconductor discharge tubes (TSS, model P0300SD), with a residual voltage of ≤25V and a response time of nanoseconds. They have both surge and static protection capabilities to ensure signal integrity：
Meet IEC 61000-4-2 electrostatic class 4 (contact discharge 8kV, air discharge 15kV)；
Meet the IEC 61000-4-5 surge 10/700μs (8kV)。
4. Communication interface enhancement scheme
Gigabit network interface (outdoor scenario)
l Secondary protection scheme：
The pre-stage GDT (3R090-5S) discharges amplification current, and the post-stage ESD device (GBLC03C, 0.6PF low capacitive reactance) suppresses high-frequency noise.
It meets IEC 61000-4-2 (contact/air discharge ±30kV) and IEC 61000-4-5 (6kV surge), and does not lose packets during transmission in high-temperature environments.
RS485 bus
Low residual voltage TSS (P0080SC) is adopted, with a capacitive reactance of 100PF to adapt to high-speed signals: