Sliding Mode Control of Three-Phase Voltage Inverter Based on Improved Generalized Proportional Integral Observer

This paper mainly introduces the voltage control of the improved generalized proportional integral observer (IGPIO) in the three-phase voltage inverter. To resolve chattering problem caused by symbolic function in sliding mode control (SMC), we use nonlinear smoothing function instead of symbolic function in power reaching law. The novel approximation law effectively reduces the output voltage buffeting. First, we set up a dynamic a three-phase voltage inverter model of the system is established, and its dynamic model is transformed into a new model including lumping interference (load interference, external parameter uncertainty, unmeasured inductance current). According to the established new inverter model, an IGPIO was constructed to estimate the external interference. Compared with the generalized proportional integral observer (GPIO), the IGPIO took the DC bus voltage differential and the observed value into account, the observation accuracy is improved and the anti-interference ability is stronger. Finally, individual sliding mode controllers are tailored for both the d-axis and q-axis to ensure swift and precise voltage tracking. Experimental testing demonstrates that this approach leads to diminished output voltage oscillations and exhibits enhanced resilience against interference caused by load variations.