ABSTRACT:
Photovoltaic
(PV)/battery hybrid power units have attracted vast research interests in
recent years. For the conventional distributed power generation systems with
PV/battery hybrid power units, two independent power converters, including a
unidirectional dc_dc converter and a bidirectional converter, are normally
required. This paper proposes an energy management and control strategy for the
PV/battery hybrid distributed power generation systems with only one integrated
three-port power converter. As the integrated bidirectional converter shares
power switches with the full-bridge dc_dc converter, the power density and the
reliability of the system is enhanced. The corresponding energy management and
control strategy are proposed to realize the power balance among three ports in
different operating scenarios, which comprehensively takes both the maximum power
point tracking (MPPT) benefit and the battery charging/discharging management
into consideration. The simulations are conducted using the Matlab/Simulink
software to verify the operation performance of the proposed PV/battery hybrid
distributed power generation system with the corresponding control algorithms,
where the MPPT control loop, the battery charging/discharging management loop
are enabled accordingly in different operating scenarios.
KEYWORDS:
1. Energy
management
2. Maximum power point tracking
3. Bidirectional
power converter
4. Photovoltaic/battery
hybrid power unit
SOFTWARE:
MATLAB/SIMULINK
CONCLUSION:
An
integrated three-port power converter as the interface for the PV/battery
hybrid distributed power generation system is proposed. Compared with the
conventional system topology containing an independent DC-DC unidirectional
conversion stage and a bidirectional conversion stage, the proposed system has
advantages in terms of higher power density and reliability. The phase shift
angle of the full bridge and the switch duty cycle are adopted as two control
variables to obtain the required DC bus voltage and realize the power balance
among three ports. Different operating scenarios of the system under various
power conditions are discussed in detail and a comprehensive energy management
and control strategy is proposed accordingly. The priority controller can
enable one of the control loops in different scenarios to optimize the whole
system performance, taking both the MPPT benefit and the battery
charging/discharging management requirements into consideration. The simulation
results verify the performance of the proposed PV/battery hybrid distributed
power generation system and the feasibility of the control algorithm.
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