DC/DC transformation topology circuit of high-voltage switch power supply

Abstract

The DC / DC topological circuit for high-voltage switch power comprises two semi-bridge converters every with primary side in series with four tubes (Q1-Q4) and capacitors (C1-C4) connected with input voltage Ui and the paralleled secondary side, wherein C1-C2 / C3-C4 and Q1-Q2 / Q3-Q4 form a semi-bridge structure connected with secondary side through transformer T1 / T2; Q1 / Q2 and Q3 / Q4 are controlled by same signal. This invention can be applied for higher voltage condition just by added semi-bridge converter.

Description

technical field [0001] The invention relates to a high-frequency switching power supply, and mainly refers to a DC / DC conversion topology circuit of a high-voltage switching power supply used in some DC high-voltage occasions. Background technique [0002] At present, as far as the basic pulse width adjustment (PWM) converter main circuit topology is concerned, there are Buck, Boost, Buck-Boost, Cuk and other converters. On this basis, the circuit structures of switching regulated power supplies (DC / DC converters) evolved are various. Among them, the switching tubes of the dual-tube forward and half-bridge circuits are only under the input power supply voltage, and will not There is a problem of unidirectional bias magnetic saturation, so it is widely used in high-voltage input circuits. [0003] In a half-bridge circuit (see figure 1 ), Q1 and Q2 (which can be triodes or MOS tubes, this article takes triodes as an example, the same below) are turned on in turn under the c...

AI Technical Summary

Problems solved by technology

In addition, the impact of power grid fluctuation +10% should also be considered, so the voltage that the switch tube bears is 1.2×1.1Ui=1.32Ui. When the input is 800V DC, even if the derating is not considered, the withstand voltage of the switch tube must also be Reaching Uceo=1.32×800=1056V, such a high-speed switching tube is difficult to choose

If the input is higher than 800V, reaching 1000V, 1200V, the device selection will be more difficult, or even no suitable device can be selected

When high voltage is input, the withstand voltage requirements of other devices in the circuit are also increased accordingly, and it is difficult to find devices that meet the requirements

Even if a suitable device is found, it will greatly reduce the reliability of the entire power supply if it works at a high voltage

In addition, the half-bridge circuit uses a transformer. If the current is too large, it will saturate it, and the output power cannot be made very large.

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