Decentralized Method for Load Sharing and Power Management in a PV/Battery Hybrid Source Islanded Microgrid

Abstract

This paper proposes a new decentralized power management and load sharing method for a photovoltaic based islanded microgrid consisting of various PV units, battery units and hybrid PV/battery units. Unlike the previous methods in the literature, there is no need to communication among the units and the proposed method is not limited to the systems with separate PV and battery units or systems with only one hybrid unit. The proposed method takes into account the available PV power and battery conditions of the units to share the load among them. To cover all possible conditions of the microgrid, the operation of each unit is divided into five states and modified active powerfrequency droop functions are used according to operating states. The frequency level is used as trigger for switching between the states. Efficacy of the proposed method in different load, PV generation and battery conditions is validated experimentally in a microgrid lab prototype consisted of three units. Index Terms-decentralized power management; hybrid source microgrid; hybrid PV/battery unit; SoC; PV power curtailment;

Decentralized Coordination Power Control for Islanding Microgrid Based on PV/BES-VSG

“…For the system consisting of multiple inverters, the balanced power flow should satisfy (17) when the load demands change, ΔP Load is load power variation (17) Then transfer function model can be obtained based on (14) ~ (17) (18) where, (19) G pli represents the influence of load on the output power of i th inverter. The output power of paralleled VSG-based inverter is not only related to the load demand and its own parameters, but also affected by the parameters of other inverters.…”

“…This feature of the micrgrids brings great challenges to the design of individual local controllers. In current proposed methods, each local controller in the microgrid identifies the current operation mode with accessing to local information, through a state machine method [17], or via microgrid AC bus frequency [18], [19]. In the reference [17] the control strategy mainly focuses on the power flow management between hybrid PV/BES unit and microgrid, the coordinated control of the DC-DC converters at DC side are not discussed in details.…”

“…In current proposed methods, each local controller in the microgrid identifies the current operation mode with accessing to local information, through a state machine method [17], or via microgrid AC bus frequency [18], [19]. In the reference [17] the control strategy mainly focuses on the power flow management between hybrid PV/BES unit and microgrid, the coordinated control of the DC-DC converters at DC side are not discussed in details. In [18], AC frequency is used to reflect Battery SOC condition, while the PV generation regulates its output power based on measured frequency to keep the frequency stable.…”

Decentralized method for load sharing and power management in a hybrid single/three-phase islanded microgrid consisting of hybrid source PV/battery units

“…In this case, the imbalance among charging powers of the units is increased because units in State 2 are controlled in constant power and only charging powers of units in State 1 are decreased. To ensure balanced distribution of charging power (with considering SoC of the batteries), each unit that is in State 2 should exit constant power control mode and return to State 1 when the following criterion is met [30] in which Kpm<1 is a margin used for preventing unwanted changing of state because of error in power measurement: 0 and preState 1. …”

Research on Reduction of Magnetic Flux Bias in High Frequency Isolated Interconnection Converter for AC/DC Hybrid Microgrid

“…Microgrid has been proposed to solve the problem. It can improve the stability of the power systems because it can achieve active power balance by combining distribution generator, local load, and energy storage system [2]. The hybrid microgrid, i.e.…”