Fault Diagnosis and Tolerant Control of Three-Level Neutral-Point Clamped Inverters in Motor Drives

Abstract

This paper presents an extension theory-based assessment method to perform fault diagnosis for inverters in motor driving systems. First, a three-level neutral-point clamped (NPC) inverter is created using the PSIM software package to simulate faults for any power transistor in the NPC-type inverter. Fast Fourier transformation is used to transform the line current signals in the time domain into a spectrum in the frequency domain for analysis of the corresponding spectrum of features of the inverter for faults with different power transistors. Then, the relationships between fault types and specific spectra are established as characteristics for the extension assessment method, which is then used to create a smart fault diagnosis system for inverters. Fault-tolerant control (FTC) is used here when the rated output of a faulty inverter is decreased in order to maintain balanced output in three phases by changing the framework of the transistor connection. This is performed to reinforce the reliability of the inverter. Finally, by the simulation and experimental results, the feasibility of the proposed smart fault diagnosis system is confirmed. The proposed fault diagnosis method is advantageous due to its minimal use of data and lack of a learning process, which thereby reduces the fault diagnosis time and makes the method easily used in practice. The proposed fault-tolerant control strategy allows both online and smooth switching in the wiring structure of the inverter.

Design and Control of Electrical Motor Drives

“…By using a statistical method, the experimental results that used two forms of ∆ connection were studied. Chao et al [5] proposed an intelligent fault diagnosis drive system to improve the reliability of inverters. A real-time, smooth switching method was used for fault-tolerant control.…”

“…This Special Issue contains the successful invited submissions [1][2][3][4][5][6][7][8][9][10][11] to a Special Issue of Energies on the subject of the "Design and Control of Electrical Motor Drives". Electrical motor drives are widely used in industry, automation, transportation, and home appliances.…”

A Real-Time Fault-Tolerant Control Approach to Ensure the Resiliency of a Self-Healing Multilevel Converter

“…The proposed structure is not able to restore nominal voltage and nominal total harmonic distortion in all fault cases. The authors of [23] present a fault-tolerant NPC inverter employed as a motor drive. The proposed approach cannot ensure nominal operation following a breakdown.…”

Fault Analysis and Non-Redundant Fault Tolerance in 3-Level Double Conversion UPS Systems Using Finite-Control-Set Model Predictive Control

“…A similar approach has been proposed for 2-level converters in [61,62], connecting the faulty phase to an auxiliary capacitor instead of the DC bus midpoint. In [67], 2 additional switches are used to bypass the inner IGBTs when faulty. With these approaches, the controller can only operate normally with modulation indexes below 0.5, which implies a derating of the system.…”

“…With these approaches, the controller can only operate normally with modulation indexes below 0.5, which implies a derating of the system. Even though a derating may be acceptable in some applications [30], such as motor drives [37,40,51,54,67] or generation [38,46,47,53,63,64], it is not viable in UPS applications since the system cannot compromise or restrict the operation of the protected critical load.…”