Behavioral characterization of electric vehicle charging loads in a distribution power grid through modeling of battery chargers

Abstract

Plug-in Electric Vehicle (PEV) is a new atypical load in power systems. In future, PEV load will play a significant role in the distribution grids. This integrated load into the power grid may overload the system components, increase power losses and may violate system constraints. Currently, the most common method of Electric Vehicle (EV) modeling is to consider the EV loads as constant power elements without considering the voltage dependency of EV charging system during state of charges (SOC). EV load demand cannot be considered as a constant power, as modeling as a constant power load will not provide accurate information about the behavior of charging system during charging process. As several research projects on smart grids are now looking into realistic models representing the realistic behavior of an EV loads, this paper proposes a methodology for modeling of EV charger integrated to an electricity grid in order to understand the impacts of EV charging load. A charging system was designed to capture the EV load behavior and extract the coefficients of the EV ZIP load model. A comparative study was carried out with different types of load models. The results indicate that the assumptions of load demand as a constant power to analysis the effect of PEVs on power grid would not be effective in real time application of PEVs. Abstract --Plug-in Electric Vehicle (PEV) is a new atypical load in power systems. In future, PEV load will play a significant role in the distribution grids. This integrated load into the power grid may overload the system components, increase power losses and may violate system constraints. Currently, the most common method of Electric Vehicle (EV) modeling is to consider the EV loads as constant power elements without considering the voltage dependency of EV charging system during state of charges (SOC). EV load demand cannot be considered as a constant power, as modeling as a constant power load will not provide accurate information about the behavior of charging system during charging process. As several research projects on smart grids are now looking into realistic models representing the realistic behavior of an EV loads, this paper proposes a methodology for modeling of EV charger integrated to an electricity grid in order to understand the impacts of EV charging load. A charging system was designed to capture the EV load behavior and extract the coefficients of the EV ZIP load model. A comparative study was carried out with different types of load models. The results indicate that the assumptions of load demand as a constant power to analysis the effect of PEVs on power grid would not be effective in real time application of PEVs.Index Terms--Plug-in electric vehicle; EV load modeling, Battery charger, Battery state of charge

A modified current injection load flow method under different load model of EV for distribution system

“…The bus which has maximum loss saving value is chosen as the best location to allocate a DG. The optimal locations of scheduled power of DG for all the load models are bus number 2,5,28,8,15,27,3,14,29 and 30. Figure 14 shows the scheduled power of DGs placed at theses buses.…”

Parameter-Independent Control for Battery Chargers Based on Virtual Impedance Emulation

“…The most common method to control the battery voltage is by directly using an integral or PI controller [26]- [28], [33]. This method is very simple and its scheme is shown in Fig.…”

“…During CC mode, I * bat,CC is selected and the outer loop is thus deactivated. Then, during CV mode, I * bat,CV is selected and reduced below I * bat,CC in order to control the battery voltage [26]- [30]. Excluding low power applications, the cascaded solution is preferred since the battery current is always controlled.…”

“…Despite this fact, many authors design the voltage controller for a certain impedance value, without considering how impedance variation can affect the control [24], [26]- [28], [33], [34]. As will be shown in this paper, this leads to an extremely variable performance of the voltage control, which becomes either too slow or too fast at some operating points, and could even become unstable.…”

On the equivalent ZIP parameter extraction of desktop computer cases and LCD monitors connected in parallel

“…[1], [3], [16], [17], [8]- [15]. ZIP parameter models are commonly used to estimate static loads power consumption or loads operating in steady-state applications [1], [5]- [9]. There are parabolic and exponential load models [11], [12].…”