Control of High-Performance Drive Feeding by Four-Level Hybrid Clamped Converter for Transportation Electrification

The internal capacitor voltages of a four-level hybrid clamped converter (4L-HCC) can have serious instability issues without proper control, limiting its application in variable speed drives for transportation electrification. This article presents a new integrated control scheme for an electrical machine drive fed by the 4L-HCC. Compared with the traditional PWM control, the proposed method effectively minimizes the ac voltage fluctuations and dc voltage deviations for all dc-link and flying capacitors. The advantages of the proposed control method include easy implementation, accurate current and speed control, and strong capacitor-voltage-balancing capability. Four-quadrant operation with a high dynamic response is achieved over the full-speed range of the system. Simulation and experimental results are presented to validate the effectiveness of the proposed integrated method.