Boosting power converting circuit and control method

Abstract

The invention provides a boosting power converting circuit and a control method. The circuit comprises N first switch modules, N second switch modules, N-1 third switch modules, N-1 flying capacitors and N-1 pre-charging units, wherein the N second switch modules are serially connected with an inductor and an input power supply so as to form a loop; N first switch modules are serially connected with a load, the inductor and the input power supply so as to form the loop; the flying capacitors and the third switch modules are connected between the first public points which are between the first switch module and the first switch module and the second public points which are between the second switch module and the second switch module; each of the flying capacitors is in parallel connection with each of the pre-charging units; each of the pre-charging units is used for pre-charging each of the flying capacitors and guaranteeing the voltage of each flying capacitor not below 0V when the third switch modules connected with the flying capacitors in parallel connection with the pre-charging units are switched off and the voltages of the flying capacitors are less than a preset threshold value, so that the problem of possibly breaking down the semiconductor device through overvoltage when the boosting power converting circuit is used in a boosting system is avoided.

Description

technical field [0001] Embodiments of the present invention relate to electronic circuit technology, in particular to a boost power conversion circuit and a control method. Background technique [0002] Boost circuit does not specifically refer to a specific circuit, but generally refers to a boost circuit, that is, through this circuit, a voltage can be input, a higher voltage can be output, and power conversion can be realized. It can input more than or equal to three levels. It is a multi-level Boost circuit. [0003] Figure 1a It is a flying capacitor multilevel Boost circuit, Figure 1b It is a control signal schematic diagram of a flying capacitor multi-level Boost circuit, such as Figure 1a , Figure 1b As shown, L is an inductor, D1, D2, D5, and D6 are diodes, T1, T2 are semiconductor switches (which can be insulated gate bipolar transistors (English: Insulated Gate Bipolar Transistor, referred to as: IGBT), metal-oxide layer Semiconductor field effect transisto...

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Problems solved by technology

[0004] However, according to the above analysis, it can be seen that Vout>Vin, all switching tubes can choose a withstand voltage of 0.5Vout; if there is no voltage on the flying capacitor, that is, Vc=0, and the capacitor voltage is 0, then the capacitor can be regarded as a short circuit, that is, the T1 tube Short-circuited by D1 and D5 in both directions, at this time T2 and D2 bear the input voltage Vin, and D6 bears the withstand voltage Vout-Vin; if Vin0.5Vout, if the withstand voltage exceeds D6, D6 will break down overvoltage; if Vin>0.5Vout, then T2 and D2 withstand the input voltage Vin, Vin>0.5Vout, if the withstand voltage of D2 and T2 exceeds 0.5Vout, D2 and T2 will break down due to overvoltage; D6 withstands the withstand voltage Vout-Vin, Vout-Vin<0.5Vout, not exceeding D6 Withstand voltage, D6 will not be overvoltage breakdown; from the above analysis, if the flying capacitor voltage Vc is zero, the semiconductors in the above scheme are at risk of overvoltage breakdown

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