1. 极化 & 非极化

2. 电压 & 电流

基础

功能

1. reduce the electrical stresses placed on a device during switching by a power electronics converter to levels that are within the electrical ratings of the device.
1. 减少开关时的电应力

2. snubbers are not a fundamental part of a power electronic converter circuit. The snubber circuit is an addition to the basic converter, which is added to reduce the stresses on an electrical component, usually a power semiconductor device.
1. 并非必须，而是补充

分类

1. 依据
1. circuit topology perspective 电路拓扑角度

2. 分类
1. Unpolarized series R-C snubbers:
• Used to protect diodes and thyristors
• Used to Mitigate Ringing
Polarized R-C snubbers:
• Used as turn-off snubbers to shape the turn-off switching trajectory of controlled switches. Limit dv/dt during device turn-off
• Used as overvoltage snubbers to clamp voltages applied to controlled switches to safe values;
Polarized L-R snubbers
• Used as turn-on snubbers to shape the turn-on switching trajectory of controlled switches;
• Limit di/dt during device turn-on

设计

1. There is always a degree of experimentation needed to tune a snubber’s operation. It is impossible to precisely design the circuit (although the desired function can be predicted).
1. 需要实验

2. The final circuit will probably be a compromise. A capacitive snubber that controls a voltage spike at turn-off may cause a current spike at turn-on. Similarly, controlling a current spike on one edge may cause a voltage spike on the other.
1. 综合考虑，妥协得出

switch opens

When switch opens, capacitor charges up, limiting . (Desired)

 

switch closes

When switch closes, capacitor is shorted, causing current spike. (Undesired)

 

Ringing Effect 振铃响应

原因

1. Real electronic switches have a “parasitic” capacitance between their terminals, and circuit board tracks introduce stray inductance between components.

计算

1. 无阻尼振铃频率

2. R & C 最佳值

3. 耗散功率 & 电阻能量 &

电路

工作原理

1. 降低变化率

电路图

RC缓冲器

极化

Polarized R-C snubber – Turn-off Snubber

Polarized R-C snubber – Turn-on Snubber

 

计算

Polarized R-C snubber – Turn-off Snubber——关断损耗 & 电阻功率

Polarized R-C snubber – Turn-on Snubber——电感能量 & 耗散功率 & 电流上升速率限制