Continuous dynamic sliding mode control strategy of PWM based voltage source inverter under load variations.

Area of Science:

• Electrical Engineering
• Control Systems

Background:

• DC-AC inverter performance is degraded by load variations and current sensor inaccuracies.
• Faulty current measurements render traditional feedback control ineffective.

Purpose of the Study:

• To propose a sensorless continuous sliding mode control (SMC) scheme for DC-AC inverters.
• To address performance issues caused by load variations and current sensor faults.

Main Methods:

• Developed a sensorless continuous sliding mode control (SMC) scheme.
• Implemented a novel boundary-based saturation function to mitigate SMC chattering.
• Utilized particle swarm optimization (PSO) to design a modified observer for sensorless inductor current estimation.

Main Results:

• The proposed dynamic smooth SMC algorithm demonstrated rapid dynamic response in simulations.
• Achieved a low steady-state error of 0.4V peak-to-peak voltage under linear and nonlinear load perturbations.
• Reduced total harmonic distortion (THD) to 0.20% for linear loads and 1.14% for non-linear loads.

Conclusions:

• The sensorless SMC scheme effectively handles load variations and eliminates reliance on current sensors.
• The PSO-optimized observer ensures accurate current estimation, enhancing control performance.
• The approach offers a robust and efficient solution for DC-AC inverter control.