Case study of voltage control for MVDC microgrids with constant power loads - Comparison between centralized and decentralized control strategies

Abstract

This paper investigates two control approaches to stabilize MVDC microgrids under large perturbations. The control approaches compared here are a 2 Degree of Freedom (2DoF) linear control and a synergetic control for voltage stability of DC microgrids, where loads and generators are interfaced through power electronic converters. The stabilizing control of the bus voltage resides in the converters on the generation side. The stability is challenged by Constant Power Loads (CPLs) that are tightly regulated within their control bandwidth exhibiting incremental negative impedance characteristic. In the scenario of a microgrid the two control approaches are compared in their centralized and decentralized formulation

DC Microgrid Planning, Operation, and Control: A Comprehensive Review

“…The most well-known and established centralized controller is master-slave controller [118]- [120]. This control strategy has several drawbacks such as single point failure, shorter battery life, and poor scalability [121]. In order to avoid single point failure, and increase battery life, the decentralized controller is presented for DC microgrids [122].…”

“…In [164], smart grid communication links are employed for multi-layer control of DC microgrids which focuses on photovoltaic (PV) constrained production, power balancing, and load shedding. In [121], two centralized control strategies, such as Linear Quadratic Gaussian (LQG) and synergetic controllers, are applied for medium voltage DC microgrids. It shows that both centralized control strategies are capable to stabilize the system in case of large load disturbances.…”

Optimal operation of hybrid AC/DC microgrids under uncertainty of renewable energy resources: A comprehensive review

“…In [13][14][15][16][17][18][19][20], the modeling, control, implementation, utilization and sensitivity analysis of a microgrid has been investigated, subject to a constant power load constraint. The constant current [21][22][23], constant impedance and a combination of constant impedance, current and power, known as a ZIP model [24,25], have also been analyzed in a few studies as well.…”

Dynamic Assessment of Source–Load Interactions in Marine MVDC Distribution

“…Another major challenge is the stability of the MVDC distribution system that arises due to the presence of the high-power motor drives and their constant power load (CPL) behavior [15]. These stability-related problems and their possible solutions can also be found in [16]- [24]. DC-side modeling of power electronic systems as impedance is reported in [16]- [18] for dc applications.…”

“…This is further extended to multiterminal dc systems in [19]. On the other hand, different control techniques for MVDC bus voltage (e.g., linearization via state feedback, backstepping, linear quadratic Gaussian, and synergetic control), in systems with buck converters connected to CPLs, are proposed and compared in [20]- [24]. Most of the literature focuses on the CPL behavior of the load side, whereas a comparison of active and passive rectifiers, when supplying pulsed loads, is given in [25].…”