Distributed Control Strategy Based on a Consensus Algorithm and on the Conservative Power Theory for Imbalance and Harmonic Sharing in 4-Wire Microgrids

The Conservative Power Theory (CPT) emerged in recent decades as a theoretical framework for coping with harmonically distorted and unbalanced electric networks of ac power systems with a high participation of converter interfaced loads and generation. The CPT measurements are intrinsically linked to moving averages (MA) over one period of the grid. If the CPT is to be used in a low-inertia isolated-grid scenario, which is subjected to frequency variations, adaptive moving averages (AMA) are necessary. This paper reviews an efficient way of computing MAs and turns it into an adaptive one. It shows that an easily available variable time delay block, from MATLAB, causes steady-state errors in the measurements when the grid frequency varies. A new variable time delay block is, thus, proposed. Nonetheless, natural pulsations in the instantaneous power slip through MAs when the discrete moving average window does not fit perfectly the continuously varying period of the grid. A method consisting of weighing two MAs is reviewed and a new and effective hybrid AMA is proposed. The CPT transducers with the different choices of AMAs are compared via computer simulations of a single-phase voltage source feeding either a linear or a nonlinear load.

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Conservative Power Theory, sequence components and accountability in smart grids

2010 International School on Nonsinusoidal Currents and Compensation ◽

10.1109/isncc.2010.5524473 ◽

2010 ◽

Cited By ~ 29

Author(s):

Paolo Tenti ◽

Paolo Mattavelli ◽

Helmo K. Morales Paredes

Keyword(s):

Smart Grids ◽

Power Theory ◽

Sequence Components ◽

Conservative Power Theory ◽

Conservative Power

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Hierarchical Distributed Control Strategy for Electric Vehicle Mobile Energy Storage Clusters

Energies ◽

10.3390/en12071195 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1195 ◽

Cited By ~ 1

Author(s):

Mei Wu ◽

Yu-Qing Bao ◽

Gang Chen ◽

Jinlong Zhang ◽

Beibei Wang ◽

...

Keyword(s):

Energy Storage ◽

Power System ◽

Distributed Control ◽

Control Strategy ◽

Optimal Allocation ◽

Lower Layer ◽

Power Grid ◽

Consensus Algorithm ◽

Renewable Energy Resources ◽

Storage Unit

The stability problem of the power system becomes increasingly important for the penetration of renewable energy resources (RESs). The inclusion of electric vehicles (EVs) in a power system can not only promote the consumption of RESs, but also provide energy for the power grid if necessary. As a mobile energy storage unit (MESU), EVs should pay more attention to the service life of their batteries during operation. A hierarchical distributed control strategy was proposed in this paper for mobile energy storage clusters (MESCs) considering the life loss of each EV’s battery. This strategy was divided into a two-layer control structure. Firstly, numerous EVs were divided into different clusters according to their regional relationships. The lower layer adopted a distributed collaborative control approach for allocating energy among EVs in the cluster. Under this condition, an aggregate EVs response model was established and the characteristic of the MESC was analyzed. Secondly, the upper layer applied the multi-agent consensus algorithm to achieve the optimal allocation among different clusters. Therefore, the control strategy realized the two-way communication of energy between EVs and the power grid, and ensured the optimal economical dispatch for the mobile energy storage system (MESS). Finally, the simulation of testing examples verified the effectiveness of the proposed strategy.

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