整流器 | Rectifier

定义

整流器是一种用于将交流电转换成直流电的电子元件。

A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction.

-- Wikipedia

半波整流 | Half-Wave Rectifier

对于一个正弦波，如下图所示：

在一个半波整流电路中，随着输入电压变化，输出电压会发生如下所示的变化：

对于一个交流电源输入，经过一个半波整流器，对于其输出的直流电有：

Notes

• A real diode does not start conducting until forward signal exceeds V_D ≈ 0.7 V
• In reverse direction there is a very small leakage current
• The peak output voltage: V_p = V_m - 0.7
• The average output voltage is a small positive value: V_d = V_{out, avg} = 0.318 V_p

对于公式中的一些记号：

• V_m = V_max: maximum voltage from the transformer
• V_p = V_peek: peak voltage applied to the load

峰值逆电压 | Peak Inverse Voltage

最大的可施加在稳流器上而不使其损坏的反向电压。

The maximum reverse-bias voltage that can be applied before entering the breakdown region is called: the peak inverse voltage (referred to simply as the PIV rating), or the peak reverse voltage (denoted the PRV rating).

笔记

理论上 PIV 的值可以为任何大于 V_m 的值，但为了安全起见，一些时候会取 V_m 的倍数，如两倍。

RMS 等效电压 | RMS Voltage equivalent

正弦波形的 RMS 等效电压等同于 。

全波整流 | Full-Wave Rectification

全波整流示例电路

笔记

• In reverse direction there is a very small leakage current
• Because of centre-tap, RMS voltage for each half section = V_RMS / 2
• For peak output voltage, only one diode conducts at a time, so still have V_p = V_m - 0.7 (same as half-wave)
• However, now we have twice the average output voltage V_{out, avg} = 0.636 V
• Still have to specify PIV rating
• PIV > 2 V_m − 0.7 V, usually select double this value

桥式整流器 | Bridge Rectifier

笔记

• In reverse direction, there is still a very small leakage current
• For peak output voltage, two diodes conduct at a time so V_p = V_m − 1.4
• The same average output voltage as two-diode rectifier, V_dc = 0.636 V_p
• Have to specify PIV rating, but with no centre-tap, it is the same as for half-wave rectifier: PIV > V_m − 0.7, usually allow a factor of 2

整流器总结

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