Development of Robust-High Efficiency Low DC Capacitance Converters and Motor Drives

Power converters are essential in increasing the efficiency of electrical energy conversion. Various topologies have been developed to enhance the power characteristics and energy conversion efficiency. These include modifying power semiconductor and passive component configurations in different arrangements. A common and effective design in both industrial and academic settings is the three-phase three-level converter, which comprises three diode rectifier legs, coils, a DC-link section, and three legs of controllable power semiconductors. These modified designs necessitate a control algorithm capable of addressing system constraints and nonlinearities.

Recent research focuses primarily on power converters with reduced component counts. In a three-phase three-level converter, component reduction can be achieved by decreasing either the capacitance or inductance. However, reducing DC-link capacitance can cause significant ripples in the DC-link section, and lowering inductance may lead to fluctuations in rectifier output current. Such reductions can introduce harmonics and adverse effects on both the grid and load sides. As a result, a robust and efficient control technique is essential to mitigate these fluctuations and enhance the converter’s reliability and efficiency.

Finite Control Set Model Predictive Control (FCS-MPC) algorithm is well-known for its simplicity, fast transient response, and ability to achieve multiple control objectives within a single loop. This nonlinear algorithm integrates various cost functions to address specific issues related to power converter behavior, assigning a weighting factor to each function. Despite FCS-MPC’s advantages in power electronics, it faces challenges such as variable switching frequency, design of weighting factors, model-based nature, stability analysis, and performance under different uncertainties.

This Ph.D. program aims to explore replacing film capacitors with more cost-effective, smaller, lighter, and reliable electrolytic aluminum capacitors in power converters/motor drives. Achieving this goal involves utilizing advanced control techniques and artificial intelligence. Additionally, testing and validation of theoretical and simulation results are crucial aspects of this research, ensuring applicability and relevance to industrial applications.