Method and system for detecting and suppressing DC component of transformer current

Abstract

The invention discloses a method and system for detecting and suppressing the DC component of transformer current, belonging to the technical field of power supplies, including a sampling unit, a sampling conditioning circuit, a main control unit and a driving circuit, and solving the problem of suppressing DC based on the detected DC component of transformer current. The technical problem of the component can prevent the device from being damaged due to the saturation of the transformer. The present invention can omit the DC blocking capacitor connected in series in the transformer circuit in the prior art solution. Since the greater the power, the higher the volume and cost of the DC blocking capacitor, the current detection CT and detection The resistor has small volume and low cost, so the present invention has more advantages in product volume and cost.

Description

technical field [0001] The invention belongs to the technical field of power supplies, and relates to a method and a system for detecting and suppressing a DC component of a transformer current. Background technique [0002] In recent years, with the rapid development of switching power supply technology, power transformers have been widely used in various industries such as household appliances, photovoltaics, charging piles, and server power supplies. circuit), and then converted to the voltage required by the user through a DC-DC converter (DC / DC circuit). Usually, in order to realize the electrical isolation between the user side and the AC grid side considering the safety factor, the DC / DC circuit usually adopts the DC / DC circuit with high-frequency transformer isolation. Forward converter, hard-switching half-bridge converter, hard-switching full-bridge converter, phase-shifting full-bridge converter, LLC converter, dual active bridge converter, etc. [0003] Some of...

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Problems solved by technology

However, this solution will lead to an increase in the excitation current, and the excitation current can not be transmitted to the secondary side, which will cause additional losses in power devices and transformers and reduce product efficiency.

[0006] Another way is to connect the DC blocking capacitor in series in the transformer circuit. Since the capacitor needs to flow through the power stage current, the larger the transformer current, the larger the volume of the DC blocking capacitor and the higher the cost.

At the same time, there will be a certain voltage drop on the DC blocking capacitor. In order to minimize the influence of the voltage drop of the DC blocking capacitor on the characteristics of the power converter, the DC blocking capacitor needs to choose a capacitor with a larger capacitance as much as possible. The larger the capacitance, the larger the volume of the capacitor. and costs will further increase

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