Independent Control Scheme for Nonredundant Two-Leg Fault-Tolerant Back-to-Back Converter-Fed Induction Motor Drives

Abstract

This paper presents an investigation on a nonredundant topology for two-leg fault at a back-to-back converter-fed induction motor drives. In the case of faults occurring in any two inverter legs, the six-leg back-to-back converter can be changed to a four-leg back-to-back converter by employing one motor phase connected to the rectifier leg and another phase connected to the dc-link capacitor mid-point for fault tolerant operation. The fourleg back-to-back converter is very attractive for the merit of not requiring additional power switches for fault-tolerant. However, as the shared-leg connection between inverter and rectifier, the rectifier and the motor drive are deeply coupled. A novel scheme based model predictive control (MPC) is presented to achieve independent control of the grid and motor currents. The voltage limitation for independent control of the rectifier and motor drive is analyzed and the dc-link voltage utilization is improved by capacitor voltage suppression. With the proposed scheme, the output speed range of the converter is degraded but other performances, such as output torque capability, unity power factor and the dynamic response, are maintained after faults occur. Finally, the control concept is verified by a TMS320F28335 DSP-based prototype.

Open‐circuit fault‐tolerant operation of permanent magnet synchronous generator drives for wind turbine systems using a computationally efficient model predictive current control

“…T n stands for the torque rated value. It should be noted that the procedure for obtaining (17) and (19) is explained in [18].…”

“…However, voltage fluctuations and current stresses are imposed on capacitors due to the DC bus split, requiring an extra voltage sensor to limit fluctuations and the proper design of DC-link capacitors. In [19], a reconfigurable BTB topology was proposed to maintain operation under multiple faults. Apart from the split of the DC bus capacitors, six TRIACs are required to achieve fault tolerance, which leads to increased system cost and complexity.…”

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

“…This solution requires only one additional bidirectional switch per phase, making it a very cost-effective solution. This solution has been widely used in both 2-level [37,38,[40][41][42][43][44][45][46][63][64][65][66] and NPC [29][30][31][47][48][49][50][51][52][53][54][55] converters. 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.…”

“…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.…”

Direct Power Control Strategy of PWM Rectifier Based on Improved Virtual Flux-Linkage Observer

“…When the PWM rectifier technology is applied to back to back converter, photovoltaic grid connected inverter, power active filter, and so on, the power factor of system can be improved greatly, and the harmonic and reactive pollution to the grid can be effectively reduced [1,3,4]. And then, it has a broad application prospects in modern power system and equipment [5][6][7][8].…”