Control method for combined converter

Abstract

The invention discloses a control method for a combined converter. The combined converter comprises a booster circuit and an inverter. The on and the off of a switch element are controlled, so that voltage drop between a collector electrode and an emitter electrode of the switch element is greatly reduced in comparison with that in the prior art while the boosting function is realized, the switch apparatuses are reduced in comparison with those in the prior art, and the conduction loss and the on-off loss of an integral switch tube are reduced; moreover, the inverter utilizes capacitance of a passive element as an energy exchange element for reasonably dividing a circuit working area, so that the energy loss can be reduced, the service life can be prolonged, the integral loss of the converter is further reduced, the structure is simple, no energy loss element is needed in the circuit, and the working efficiency of the converter is improved.

Description

technical field [0001] The invention relates to a control method for a DC-AC converter, in particular to a control method for a combined converter with low voltage switch stress and low loss. Background technique [0002] In a solar power generation system or a fuel cell system, since a single solar cell or a single fuel cell provides direct current with a low voltage, it cannot meet the electricity demand of existing electrical equipment, nor can it meet the requirements of grid connection. It is necessary to convert the low-voltage direct current into the actually required high-voltage direct current. Therefore, the boost converter with high gain and stable performance has become a research hotspot, which is of great significance to promote the development of photovoltaic and fuel cell industries. [0003] In addition, in the field of grid connection, the traditional voltage source inverter inputs DC voltage and outputs AC voltage, which is widely used. The input DC volt...

AI Technical Summary

Problems solved by technology

At this time, the conversion process of electric energy is actually changed from the original DC-DC to DC-AC-AC-DC, and the energy conversion efficiency of the whole system is reduced.

[0009] The second is to use coupled inductors, but the structure of coupled inductors is complex, which is not conducive to industrial processing, it is difficult to ensure the consistency of the circuit, and it will cause excessive voltage stress of switching devices, which will bring electromagnetic interference and other effects, resulting in large operating losses of the converter.

[0010] The third is to add cascaded boost units, the more units, the greater the voltage gain, but the more circuit components, the more complex the structure

Although these two types of methods can realize the soft switching of the power switch tube, the external circuit is complicated, and the voltage stress of the power switch tube cannot be reduced.

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