Differential boost-buck single-phase inverter and power decoupling method thereof

Abstract

The invention discloses a differential boost-buck single-phase inverter and a power decoupling method thereof. The differential boost-buck single-phase inverter is characterized by comprising a left-side bidirectional boost-buck direct-current converter, a right-side bidirectional boost-buck direct-current converter and an alternating-current low-pass output filter circuit; the left-side bidirectional boost-buck direct-current converter is in parallel connection with the input side of the right-side bidirectional boost-buck direct-current converter, and a direct-current input source is shared; the left-side bidirectional boost-buck direct-current converter is in differential connection with the output side of the right-side bidirectional boost-buck direct-current converter to obtain altering-current output; the altering-current output is connected with the altering-current side through the alternating-current low-pass output filter circuit. The differential boost-buck single-phase inverter and the power decoupling method thereof disclosed by the invention have the benefit that under the condition that no power electronic device is additionally arranged, the inverter is modulated based on energy balance, so that a power pulse with two times of power frequencies is absorbed by output filter capacitors on the left side and the right side; a non-electrolytic capacitor can be used as an input filter capacitor, so that the use of an electrolytic capacitor is avoided, and the power density and the life of the inverter are improved.

Description

technical field [0001] The invention relates to the technical field of miniature single-phase inverters, in particular to a differential buck-boost single-phase inverter with active power decoupling function and its power decoupling control method. The inverter is mainly used in AC micro Power grids, small distributed power generation systems and small power storage systems. Background technique [0002] Small-scale power generation systems mostly use single-phase power, so single-phase inverters are widely used in small-scale distributed power generation systems. For example, in a small photovoltaic power generation system, the DC side of the inverter is connected to the photovoltaic module, and the AC side is connected to the grid. Such a connection mode determines that the single-phase inverter must meet the requirements of both sides at the same time: under certain light conditions on the photovoltaic side, the photovoltaic module works at the maximum power point, the i...

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Problems solved by technology

However, these methods require additional power electronic devices, which increases the cost of the inverter and the probability of system failure; and because these additional power electronic devices have conduction losses and switching losses, this also reduces the inverter's efficiency

In view of the problems caused by adding power decoupling circuits, "Mitigation of Low-Frequency Current Ripple in Fuel -CellInverter Systems Through Waveform Control" (author Guorong Zhu, etc.) proposed a differential boost inverter with active power decoupling function, using waveform control algorithm to import twice the power frequency pulsating power into two output filters Capacitors; "Power Decoupling Method for Single-PhaseH-Bridge Inverters with No Additional Power Electronics" published in the journal "IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS" 2015, Vol. 62, No. 8, Pages 4805-4813 ( The author Ioan Serban) proposed a differential step-down inverter with active power decoupling function, which can control twice the power frequency pulsating power to two output filter capacitors without adding any power components; in the international The article "Power Decoupling with Autonomous Reference Generation for Single-Phase Differential Inverters" (author Wenli Yao et al.) mentioned the above two differential inverters and Another differential buck-boost inverter, in which the DC voltage utilization rate of the above-mentioned differential buck inverter is low, and the switch tube voltage stress of the differential boost inverter is relatively large, so the differential boost inverter The step-down inverter has its advantages; but the mentioned differential buck-boost inverter controls the negative terminal voltage of the capacitor and cannot be connected to the grid; and the switch tube has no common source connection, which requires more complicated driving circuit

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