High boost ratio converter with bidirectional voltage output for photovoltaic modules

Abstract

The invention discloses a high step-up-ratio converter in bidirectional voltage outputting for a photovoltaic module. The high step-up-ratio converter comprises two switch tubes, two clamping diodes, two fly-wheel diodes, two output diodes, two clamping capacitors, one voltage-multiplying capacitor, two output capacitors and two coupling inductors, wherein the two coupling inductors are provided with two windings. According to the high step-up ratio converter disclosed by the invention, the coupling inductors are utilized for expanding the voltage gain of the high step-up-ratio converter and reducing the voltage stress of power switch tubes and the diodes, the leakage inductance of the coupling inductors is utilized for realizing zero-current switching of the switch tubes and restraining inverse restoring current of the diodes, a clamping circuit formed by the clamping diodes and the clamping capacitors is capable of effectively absorbing the voltage spike when a main switch tube is switched off and realizing the lossless transfer of energy, a voltage-multiply circuit is utilized for further increasing the gain of the high step-up-ratio converter and further reducing the voltage stress of the power switch tubes and the output diodes, the circuit control is convenient, the ripple of the input current is small, and the high step-up ratio converter is suitable for a photovoltaic grid-connected power generation conversion occasion in larger power, high gain and high efficiency.

Description

technical field [0001] The invention relates to a DC-DC converter and its application, in particular to a converter with a high boosting ratio for bidirectional voltage output for a photovoltaic module. Background technique [0002] In the solar power generation system, since the output voltage of a single solar cell is low, and the voltage required for inverter grid-connected power generation is relatively high, a first-stage DC-DC converter is required to convert low-voltage DC power into a high voltage suitable for grid-connected power generation. Voltage DC. In the distributed solar power generation scheme, the power capacity of a single solar cell is small, but the requirement for efficiency is high. Therefore, how to realize a high-gain, high-efficiency single-stage converter is of great significance for promoting the development of the photovoltaic industry. [0003] The voltage gain of the conventional interleaved parallel boost DC-DC converter is only determined b...

AI Technical Summary

Problems solved by technology

[0003] The voltage gain of the conventional interleaved parallel boost DC-DC converter is only determined by the duty cycle, the voltage gain is limited, and it is difficult to meet the conversion requirements of high gain

The voltage stress of the power switch tube is relatively large, and it is difficult to use a low-voltage high-performance switch tube to reduce the conduction loss

Moreover, the converter works in a hard switching state, and the switching loss is relatively large

In order to realize the soft switching action of the Boost converter, in recent years, some soft switching schemes by adding active power switches or passive devices have been studied successively. Although these circuits realize the soft switching action, they cannot reduce the voltage stress of the switching tube. It is also impossible to realize the high-gain conversion of the system

In order to increase the voltage gain of the converter, one solution is to use switched capacitors, but this solution requires a large number of switch tubes, which increases the system cost; another solution is to use a complex three-winding coupled inductor solution. The disadvantage of the scheme is that the structure of the coupled inductor is complex, which is not conducive to industrial processing, and it is difficult to ensure the consistency of the circuit

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