Photovoltaic system generates renewable energy from sunlight which has low efficiency due to the variance nature of temperature and irradiance in a fast changing environment condition. Different researchers have proposed different MPPT techniques to improve the efficiency. However, still there are many open issues. Thus, to address this, a non-linear back-stepping based higher order sliding mode controller (BHOSMC) is proposed to harvest maximum power from photovoltaic system. The PV module and load is interfaced by a non-inverted buck-boost converter (NIBBC). A linear interpolation method is used for voltage generation and a lyapunov stability is used to verify the control system equation. MATLAB/Simmulink software is used for testing the proposed controller performance. The experimental result verified that the proposed BHOSMC is robust, accurate and fast tracking, faultless and less chattering as compared to perturb and observe, back-stepping control and back-stepping based sliding mode control under fast varying meteorological condition.