This paper presents an optimal power management mechanism for grid connected photovoltaic (PV) systems with storage. The objective is to help intensive penetration of PV production into the grid by proposing peak shaving service at the lowest cost. The structure of a power supervisor based on an optimal predictive power scheduling algorithm is proposed. Optimization is performed using Dynamic Programming and is compared with a simple ruled-based management. The particularity of this study remains first in the consideration of batteries ageing into the optimization process and second in the “day-ahead” approach of power management. Simulations and real conditions application are carried out over one exemplary day. In simulation, it points out that peak shaving is realized with the minimal cost, but especially that power fluctuations on the grid are reduced which matches with the initial objective of helping PV penetration into the grid. In real conditions, efficiency of the predictive schedule depends on accuracy of the forecasts, which leads to future works about optimal reactive power management.

This paper investigates the issues of ensuring global power optimization for cascaded dc-dc converter architectures of photovoltaic (PV) generators irrespective of the irradiance conditions. The global optimum of such connections of PV modules is generally equivalent with performing the maximum power point tracking (MPPT) on all the modules. The most important disturbance occurs when the irradiance levels of modules happen to be sensibly different from a module to another - in this case, voltage-limitation requirements may be broken. The proposed supervisory algorithm then attempts to establish the best suboptimal power regime. Validation has been achieved by MATLAB/Simulink numerical simulation in the case of a single-phase grid-connected PV system, where individual MPPTs have been implemented by an extremum-seeking control, a robust and less-knowledge-demanding perturb-and-observe method.

HVDC grids are a promising alternative for the expansion of the existing AC grid. They are interesting for the integration of large-scale renewable energy sources, connecting high power offshore windfarms, interconnecting new market areas, including asynchronous AC grids and off-grid communities, and they can even provide ancillary services to the AC system. It is expected to create a more reliable and flexible transmission grid using HVDC grids. However, their development will require, among other technologies, DC-DC conversion systems. Although the DC-DC conversion techniques are well understood in low and medium voltage, a specific review on the approaches for high voltage is needed. This paper presents an overview of the DC-DC power converters dedicated to HVDC proposing a classification based on their structure. Two large families are established: those which provide galvanic isolation, and those which do not. Several sub-families are also proposed. An overview of the main HVDC applications that can be targeted with each family is also presented, highlighting the main converter requirements for each application case.