Multilevel hysteresis modulation (MHM) for sliding mode controlled dual inverter PV systems

Area of Science:

• Electrical Engineering
• Renewable Energy Systems
• Control Theory

Background:

• Photovoltaic (PV) systems require robust control strategies for stable power output.
• External disturbances and nonlinearities challenge inverter performance.
• Existing modulation techniques may not adequately address fast-tracking and disturbance rejection.

Purpose of the Study:

• To propose and characterize an adaptive multiband hysteresis modulation strategy.
• To enhance the robustness and disturbance rejection capabilities of dual two-level inverter topologies for PV systems.
• To ensure stable active power delivery in both standalone and grid-connected PV operations.

Main Methods:

• Implementation of a robust nonlinear sliding-mode control (RNSMC) strategy.
• Design and application of novel vector control schemes for improved robustness.
• Analysis of reachability and stability for controller validation.
• Utilization of Tsypkin's method for switching frequency characterization.

Main Results:

• The RNSMC strategy demonstrated robust and fast-tracking characteristics.
• Effective rejection of external disturbances was achieved.
• Stable active power was maintained across various PV operating conditions.
• Enhanced efficiency and multilevel voltage waveforms with reduced total harmonic distortion (THD) were observed.

Conclusions:

• The proposed adaptive multiband hysteresis modulation with RNSMC offers superior performance for PV systems.
• The control scheme effectively handles disturbances and maintains power quality within standards.
• Validated through simulations and real-time tests, the strategy is suitable for diverse operating conditions.