A Simple High-Performance Current Control Strategy for V2G Three-Phase Four-Leg Inverter With LCL Filter

Abstract

Electric vehicles (EVs) can behave as distributed energy storage devices for providing on-demand smart grid support service, that is an emerging Vehicle-to-Grid (V2G) technology. A high-performance and easy-implementation current control strategy for V2G Three-phase four-leg inverter with LCL filter is proposed. It consists of a deadbeat (DB) controller and a paralleled repetitive controller (RC). The DB controller is based on weighted average inductor current (WAIC) scheme, which simplifies the third-order LCL filter to be an equivalent 1st order L filter. The stability of the DB controlled inverter with the unmodelled system time delay is analyzed. DB controller is of very fast response and easy implementation, but is not immune to system time delay and various uncertainties. To overcome the disadvantages, a plug-in RC is added to reinforce the DB controller to remove harmonic distortion from the feed-in current in the presence of parameter uncertainties. A lab prototype of 10kW grid-connected threephase four-leg inverter has been built up to validate the proposed current control strategy. The simulations and experiments are provided to demonstrate the validity of the proposed control strategy. Index Terms-V2G, weighted average inductor current, three-phase four-leg inverter, deadbeat control, repetitive control, stability analysis. I. INTRODUCTION Vehicle-to-grid (V2G) technology allows electric vehicles (EVs) to act as distributed energy storage devices. It can provide smart grid support services by "valley filling" and "peak shaving" [1-4]. Fig. 1 shows a V2G application example, where the EVs can improve the efficiency, stability and economy of the grid[5, 6].

An Improved Deadbeat Control Strategy Based on Repetitive Prediction Against Grid Frequency Fluctuation for Active Power Filter

“…This is an equation about z, where one of the solutions is z=0, then the remaining solutions could be described by (27). 3 2 RC…”

“…In reference [25], in order to enhance the steadystate harmonic compensation performance, repetitive control is connected in series to deadbeat control channel, but the delay of repetitive control also reduces the dynamic response speed. In reference [26]- [27], repetitive control is paralleled to the deadbeat control channel, this way could raise the dynamic response speed of APF. However, the inherent delay of SPWM is not considered in the control system, resulting in a deviation between the theoretical model and the actual situation.…”

Overview and Future Challenges on the Connection of Electric Vehicles into Modern Distribution Power Systems

“…Through its use, it is possible, for example, to schedule low-demand or low-cost times to charge the vehicle's battery and, therefore, reduce costs for the charging operation [16]. Such solutions are well documented in the current international literature and use various analysis strategies, including single and multi-objective optimization, to demonstrate that they are feasible and advantageous from both economic and technical perspectives [17].…”

“…V2H technology allows the EV to supply power to specific loads in a home. Its application relates to the load curve and is associated with emergencies due to interruption of energy supply through the distribution network [16][17]. V2V technology, on the other hand, allows power exchange directly between electric vehicles, without the need for an intermediate charging station in the process.…”

“…In a complementary way, this concept allows the exchange of traffic information between vehicles through sensors, consequently granting greater safety for the vehicle's driver. It is important to note that V2G technologies are linked to the concept of smart cities and smart-grids, as both require an intelligent charging point to carry out EV charging or supply energy to the local distribution network [16][17].…”