Unipolarity switch power supply freewheeling denoising and parameter calculating method

Abstract

The invention discloses a unipolarity switch power supply freewheeling denoising and parameter calculating method. The method takes reduction of electromagnetic noise of a unipolarity switch power source as its goal, aims to reduce electromagnetic noise excitation energy of the switch power source, employs a forward-reverse excitation common mode, through synchronization freewheeling of a filtering inductor and a transformer, inhibits a current and voltage jump amount applied to a switch device the instant when excitation pulses are closed, reduces a change speed, enables stable on-off conversion of the switch device, and effectively prevents a ringing phenomenon caused by rapid on-off conversion. If the method is combined with a unipolarity switch power supply quasi-resonance work mode, switch noise voltages can be comprehensively inhibited, and the differential mode noise voltage of the outlet of a designed switch power supply sample can reach 2 mV below.

Description

1. Technical field [0001] The content of the present invention belongs to the field of electromagnetic compatibility technology (EMC) and low-voltage power supply technology. It is a measure for the continuous current of the transformer through the output filter inductor of the unipolar positive and negative excitation switching power supply to reduce the switching noise of the power switching device. It is the embodiment of electromagnetic interference (EMI) suppression technology in switching power supply, and is closely related to switching power supply manufacturing technology. 2. Background technology [0002] At present, switching power supply has become the main power supply device of electronic equipment, and has been popularized in various electronic equipment manufacturing fields. The prominent disadvantage of the power supply at the beginning is the large electromagnetic interference. It can be said that the switching power supply is still in a relatively prominen...

AI Technical Summary

Problems solved by technology

Some only use the anti-excitation method, the output power is small, the circuit structure is simple, and the switching noise is often relatively large, which is actually difficult to overcome.

Some adopt positive and negative excitation sharing method, and its output power is larger than that of a single anti-excitation power supply. It has a wider range of applications, and the problem of switching noise is also suppressed in one step.

At present, the best technical method for unipolar switching power supply to suppress switching noise is to adopt quasi-resonant working mode, which can well eliminate the turn-on noise of the excitation tube and the positive excitation rectifier, and the turn-off noise of the reverse excitation rectifier, but it cannot solve the problem. Turn-off noise of the excitation tube and forward-excitation rectifier, suppression of turn-on noise of the reverse-excitation rectifier, etc.

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