Three-Level Inverter Control Techniques: Design, Analysis, and Comparisons

Abstract

This work addresses the analysis and design of various Proportional-Integral-Derivative (PID) control techniques for a three-level inverter. Multilevel power converters are modern and basic elements of high-voltage electric drive and power supply systems. By using simulations and specific computer-aided design tools, the overall functional characteristics of multilevel converters, as well as the electrical demands of the components, can be accurately assessed to obtain an appropriate control solution. An innovative and detailed software model of a three-level inverter is developed and then used for the implementation of control techniques. Several tuning methods are used to tune PID controllers for two specific cases: the multilevel inverter with a linear load and with an asynchronous motor load, respectively. A detailed analysis and comparisons of the quality criteria and control performance are achieved. This analysis shows that the choice of controller type depends on the inverter load. For the linear load, proper results are obtained with a PI Nichols-tuned controller, and for the asynchronous load, with a PI controller tuned via a modified Hokushin method. The computer-aided design tools can be further used for the simulation of the equipment in various operating conditions, normal and fault, following all functional parameters.

A Sensor-Based System for Fault Detection and Prediction for EV Multi-Level Converters

“…This method is based on the use of existing systems of voltage and current sensors in conventional three-phase multilevel inverters, without the use of additional ones. The measured electrical signals are used both in the direct current charging circuit and the control and regulation system of the multilevel inverters [44,45]. The proposed fault diagnosis method achieves the detection of all types of faults for all power components, IGBTs, diodes or capacitors, in multilevel inverters.…”