The manuscript presents a novel power electronics sliding mode control design for photovoltaic energy conversion systems. In order to maximize the power generation from solar panels, P&O maximum power point tracking algorithm is applied. The purposed first and high-order sliding mode control techniques are developed to overcome the irradiance and load fluctuation challenge, and to optimize the power conversion efficiency. Compared with the first-order method, the higher-order sliding mode approach can significantly reduce the chattering effect in the Buck-Boost converter. The output of the DC-DC converter is then fed into a voltage-oriented control based SVPWM inverter for three-phase AC power generation. Computer simulation studies have shown the effectiveness and robustness of the proposed power electronics control approach for solar energy systems.