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|JEET, Vol. 13, No. 2, March 2018
| New Control Method for Power Decoupling of Electrolytic Capacitor-less Photovoltaic Micro-Inverter with Primary Side Regulation
|| B - Electric Machinery and Power Electronics
||This paper presents a novel power decoupling control scheme with the bidirectional buckboost
converter for primary-side regulation photovoltaic (PV) micro-inverter. With the proposed power
decoupling control scheme, small-capacitance film capacitors are used to overcome the life-span and
reliability limitations of the large-capacitance electrolytic capacitors. Then, an improved flyback PV
inverter is employed in continuous conduction mode with primary-side regulation for the PV power
conditioning. The proposed power-decoupling controller shares the reference for primary side current
regulation of the flyback PV inverter. The decoupling controller shapes the input current of the
bidirectional buck-boost converter. The shared reference eliminates the phase-delay between the input
current to the bidirectional buck-boost converter and the double frequency current at the PV primary
current. The elimination of the phase-delay in dynamic response enhances the ripple rejection
capability of the power decoupling buck-boost converter even with small film capacitor. With
proposed power decoupling control scheme, the additional advantage of the primary-side regulation of
flyback PV inverter is that there is no need to have an extra current sensor for obtaining the ripplecurrent
reference of the decoupling current-controller of the power-decoupling buck-boost converter.
Therefore, the proposed power decoupling control scheme is cost-effective as well as the size benefit.
A new transient analysis is carried out which includes the source voltage dynamics instead of
considering the source voltage as a pure voltage source. For verification of the proposed control
scheme, simulation and experimental results are presented.
||Active power decoupling,Bidirectional buck-boost converter,Primary side regulation,Film capacitor