University of South Wales Master of Sciences Thesis
Standalone hybrid generation system for the remote area of Thar, Pakistan
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- Điều hướng trang này:
- 2.6.4.1. Charging/Discharging Controlling model
- Fig. 2.35
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Standalone hybrid generation system for the remote area of Thar, Pakistan Fig. 2.34 Battery Charging/Discharging control algorithm The above algorithm shows the comparison of energies from the supply side and the demand side in the presence of rechargeable battery bank for testing its charging/discharging conditions. When the supply is greater than the demand, the battery bank enters into the charging state and the next condition is tested. With the first requirement at hand, the battery charges if the energy in the battery at any time is less than the maximum energy capacity of the battery. Otherwise, the battery will neither charge nor discharge though the supply still exceeds the demand. When the energy demand exceeds the supply, the battery may enter into the discharging mode to help supplying the load provided that the energy in the battery is greater than the minimum limit; otherwise it neither charges nor discharges. When the demand is also equal to the supply, the battery will neither charge nor discharge and the battery energy remains constant. 2.6.4.1. Charging/Discharging Controlling model Based on the charging/discharging algorithm (Figure 4-5), “Charging/discharging control” model could be designed so that each PMS can make use of it to take care of the battery bank. Let’s consider the following simple equivalent circuit model for a rechargeable battery bank connected with other elements at the DC-bus. Fig. 2.35: Simple equivalent circuit model of rechargeable lead acid battery Standalone hybrid generation system for the remote area of Thar, Pakistan Applying a simple KVL, the voltage at the battery terminal can be expressed as: 45 The power that is drawn from the battery is also given as: 46 The energy, which is left in the battery after the load has drawn power from the battery, can also be expressed as: 47 Where: - The charging/discharging of the battery can be indicated by the presence of current flow. If the battery is neither charging nor discharging, there will be no current flow and thus no power is available in the battery. In this thesis, the sign of battery current or power identifies the charging or discharging modes. According to the convention used in this thesis, a positive current or power shows the discharging mode and a negative current or power indicates the charging of the battery. When modeling for the simple electrical circuit that represents the rechargeable battery bank, three important points have to be considered. These are: - tải về 6.62 Mb. Chia sẻ với bạn bè của bạn:
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