Sliding Mode Control on Photovoltaic System

Chong, Yew Wei (2020) Sliding Mode Control on Photovoltaic System. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Maximum power point tracking (MPPT) algorithm is used in the photovoltaic (PV) system to optimize the performance of the system and maintain the operating point of the system atlthe maximumlpowerlpoint (MPP), which is dependent on the atmospheric conditions and the ambient temperature. Recently, there are many types of MPPT techniques have been introduced and widely used for commercial and residential. One of the popular techniques that are widely used by the public is the perturblandlobserve (P&O) MPPT technique. Thislmethodlis very common and popular due to its ease oflimplementation andlsimplicity. However, there are two limitations to this technique, which is the tradeofflbetween the convergence speed andlsteady-state error and the deviation from the MPP under rapidly-changinglatmospheric conditions. These issues contribute to the powerlloss of the PVlsystem. Therefore, this project proposes a dual-loop control approach to address the issues above and increase the performance of the system in terms of convergence speed. This proposed technique is combined the sliding modelcontroller with the P&OlMPPT controller, and the MATLAB/Simulink is used for the simulation studies and validation of the proposed technique. Basically, the Simulink is used to design the conventional P&O MPPT and the sliding mode control based P&O MPPT. Both methods are using the photovoltaic model of PV-EE125MF5F, Mitsubishi, incorporate with the boost converter. The design of the sliding mode control P&O MPPT complies with the stability criteria to assure that the stability of the system. The conventional P&O MPPT and the proposed method is compared in term of tracking ability, convergence speed and also the steady-state error. Basically, both methods will test under three different irradiance levels such as 1000, 800 and 500 and under a rapid changing irradiance level., to analyze the convergence speed, steady-state error and also the tracking ability of both methods. The proposed method exhibited faster convergence speed compared to P&O MPPT, it attains to MPP within 1 millisecond, while the conventional P&O MPPT required around 5 seconds to attain the MPP, which is 5000 times faster than the conventional P&O MPPT. Aside from this, the proposed method has a better tracking ability compared to P&O MPPT. Even though under a rapid changing irradiance level, the proposed method still able to attain the MPP in no time, while the conventional P&O MPPT took a longer period of time to attain the MPP and when there is a significant change of irradiance level, the operating point will deviate away from the MPP. Consequently, this contributes to the power loss.