Power module anti-surge interference rectification plan

GW MB10F 0.8A 1000V rectifier bridge

MOS power IC full range

L0504-Murata muRata common mode inductor 90Ω 150mA

Overview:
Through the rectification case of the surge protection of the switching power supply module, it is concluded that the main cause of the failure of the power supply board during the surge test is the existence of overvoltage protection circuit and PFC circuit design defects, and the improvement of the anti-interference of the control circuit is proposed. Design. After the rectification, the surge injection test was performed again and the device was not restarted.

Introduction Switching operation, switching of capacitor banks, switching of thyristors, short circuit to ground or arc faults can generate overvoltage or overcurrent on the grid.
The surge impact test is an interference test that simulates such overvoltage and overcurrent. The electronic equipment connected to the power grid has the requirement of surge impact immunity, and is generally tested according to the test method specified in GB/T 17626.5.
In the standard, it is emphasized that the device under test is in working state, and it is required that the working mode cannot be changed and data loss cannot be performed. At present, the frequency of switching power supply design is gradually increasing, and the number of digital control parts is increasing, which is more and more sensitive to interference. Many of the faults in the anti-interference test are caused by unreasonable control circuit design. The following is a practical case to illustrate the typical problems encountered in the anti-interference test of the switching power supply and the details that should be paid attention to in the design.

1 The product under test is an electronic product that uses 220 V AC power supply, mainly consisting of a power module and a digital processing module, as shown in Figure 1. This test is mainly for the anti-interference problem of the power supply, and introduces the composition and principle of the power module.
This power supply consists of an input unit, an active power factor correction unit, a switching power conversion and an output unit. Active PFC, active PFC, uses active components, control lines, and power-type switching components. The basic operating principle is to adjust the input current waveform to be as similar as possible to the input voltage waveform. The power factor correction value can reach nearly 100%. In addition, the active PFC can amplify the power supply input voltage range from 90V DC to 264 V (DC). The power conversion unit includes electronic switches, pulse width modulation control, and feedback functions; the output unit includes functions such as secondary rectification and smoothing filtering.
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