The reason for the unstable voltage output from the rectifier bridge

The voltage instability generated by the rectifier bridge may be caused by the following reasons:

1. Ripple current: During the process of converting AC power to DC power, there will still be some ripple components in the output DC current of the rectifier bridge. This is due to the working principle of the rectifier bridge itself and the inability of the capacitor filter to completely smooth the ripple.

This ripple current can cause fluctuations in the output voltage, resulting in instability.

2. Insufficient capacitor filtering: Capacitor filters are generally used at the output of rectifier bridges to reduce ripple current and smooth the output DC voltage waveform. If the capacitor is too small or selected improperly, the filtering effect may not be ideal, resulting in significant fluctuations in the output voltage.

3. Load variation: The output voltage of the rectifier bridge is affected by load variation. When the load changes, the stability of the voltage may deteriorate. For example, when the load current suddenly increases, the output voltage of the rectifier bridge may decrease, and vice versa.

4. Mismatch of rectifier bridge component parameters: The rectifier bridge is composed of multiple diodes. If some of the diode parameters have significant differences, such as different conduction voltages and reverse recovery times, it may lead to uneven operation of the rectifier bridge,

Thereby causing instability in the output voltage.

5. Input power supply fluctuation: The stability of the rectifier bridge is also affected by the fluctuation of the input AC power supply. If there is significant fluctuation or noise in the input power supply itself, it may be transmitted to the output voltage through the rectifier bridge, resulting in voltage instability.

In order to improve the stability of the output voltage of the rectifier bridge, appropriate measures can be taken, such as increasing the capacitance of the filtering capacitor, optimizing the load design, selecting matching rectifier bridge components, stabilizing circuits, etc., to reduce ripple and voltage fluctuations. Meanwhile,

Providing stable input power and reducing external interference are also important factors in maintaining stable output voltage.