A photovoltaic inverter using hybrid power devices

Abstract

The invention relates to the technical field of photovoltaic grid-connected inverters. A photovoltaic inverter employing a hybrid type power device comprises two parts, namely, a power inversion unit and an inversion control unit, wherein the power inversion unit mainly comprises an input EMI (Electro-Magnetic Interference) filter circuit, an interleaving Boost boosted circuit, a full bridge inversion circuit employing a mixer and an output grid-connected filter circuit; the inversion control unit mainly comprises a power grid phase detection circuit, a sampling circuit and a controller. The photovoltaic inverter adopts a double-stage structure, and the first stage adopts interleaving Boost boosted voltage, so that the fluctuation of current is reduced, and output voltage ripple is reduced; the later stage inversion unit adopts a hybrid power device, so that the inversion consumption is effectively reduced, and the system efficiency is improved. The photovoltaic inverter has the characteristics of simple structure, easiness in circuit control and convenience in capacity expansion.

Description

technical field [0001] The invention relates to the technical field of photovoltaic grid-connected inverters, in particular to a photovoltaic grid-connected inverter using hybrid power devices. Background technique [0002] With the advancement of photovoltaic silicon material refining technology and the continuous decline in cost, solar grid-connected power generation technology has developed rapidly. As a key link in electric energy conversion, power electronic converters play a pivotal role in the overall performance and reliability of photovoltaic systems. System efficiency is one of the key considerations in the design of solar photovoltaic inverters. The smallest possible power loss not only saves energy, but also reduces temperature rise, improves system reliability, and makes the system more compact, thereby reducing costs. . The conventional two-stage grid-connected inverter usually adopts a Boost boost circuit in the front stage, and a full-bridge inverter with th...

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Problems solved by technology

When the four power tubes usually use IGBTs, because the IGBT switching frequency is lower than that of MOSFETs, the switching speed is slow, the harmonics are large, and the grid-connected current waveform is poor.

However, when the four power tubes usually use MOSFETs, the conduction loss of the MOSFETs is large, which reduces the system efficiency, and the system generates serious heat when the power is high.

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