Sliding Mode Control with Direct Power Control for Three-Phase AC-DC Converter

Abstract

Three-phase AC-DC converters are common in the contemporary power electronic systems like power interfaces of renewable energy sources and sources, motor drive, electric vehicle charge stations, and high-voltage DC transmission. These applications need converters that have the ability to hold a steady DC-link voltage and at the same time achieve high power quality at the grid interface. The traditional diode rectifiers cannot fulfill these necessities because of low power factor and high levels of harmonic distortions. Thus, the pulse-width modulation (PWM) rectifiers along with the sophisticated strategies of control have been utilized as one of the vital solutions in power conversion systems of the modern era. This paper gives a Direct Power Control (DPC) approach to a three-phase AC to DC converter combined with Sliding Mode Control (SMC) to control DC-link voltage. The suggested solution applies a classical switching-table-based DPC scheme to directly control the active and reactive power exchanged between the converter and the grid at the moment. Sliding mode control would be introduced in outer control loop to make the voltage regulation more robust and dynamic performance of the system during disturbances and variations in parameters. A mathematical model of converter system is prepared and run in MATLAB/Simulink. It is tested on the proposed control system under various operating conditions such as steady-state operation, changes in loads, grid voltage disturbances and changes in the DC-link capacitance. The simulation findings reveal that the proposed DPC-SMC approach has faster transient response, better disturbance rejection capacity, less DC-link voltage ripple and less harmonic distortion than the traditional PI-based DPC control. The converter operates with almost unity factor power operation with sinusoidal input currents. The findings show that sliding mode control combined with direct power control serves as a viable and effective control device to power electronic devices when connected to the grid using AC-DC converters in contemporary power electronics.