Parvin Moamaei

A New Fault-Tolerant Strategy Based on a Modified Selective Harmonic Technique for Three-Phase Multilevel Converters With a Single Faulty Cell

This paper proposes a new fault-tolerant strategy to revamp performance of three-phase multilevel converters with a single faulty switch. The proposed fault-tolerant strategy is based on the application of a modified selective harmonic elimination (SHE) technique in conjunction with the fundamental phase-shift compensation method. The proposed fault-tolerant strategy makes the most use of the converter capacity in the faulty condition, generates balanced line voltages, and eliminates a wide range of lower order harmonics to limit the total harmonic distribution of the converter voltages in the faulty condition. In this paper, first, a brief background about cascaded H-bridge multilevel converters and SHE technique is provided. Then, the proposed fault-tolerant strategy and the modified SHE technique are presented. Finally, several experimental results are provided to validate the operation of the proposed strategy.

Unbalanced Selective Harmonic Elimination for fault-tolerant operation of three phase multilevel Cascaded H-bridge inverters

This paper proposes a new modulation method for balanced operation of a multilevel inverter with a faulty switch. This modulation method is based on Selective Harmonic Elimination (SHE) and can be implemented in different multilevel topologies, primarily in Cascaded H-bridge (CHB) inverters. In this paper, first the general concept of SHE is explained briefly. Then, the proposed switching strategy for fault-tolerant operation of a CHB with one faulty switch is presented. Finally, experimental results are provided to validate the proposed switching.

A modified selective harmonic elimination method for fault-tolerant operation of multilevel cascaded H-bridge inverters

This paper presents a novel switching strategy based on Selective Harmonic Elimination (SHE) for the fault-tolerant operation of multilevel cascaded H-bridge (CHB) inverters. In this paper, first the structure and operation of a 7-level CHB is reviewed and the general SHE concept for this type of inverter is studied briefly. Then, the proposed fault-tolerant switching strategy for a CHB with one faulty switch is presented. Finally, simulation results are provided to validate the proposed modulation technique.

Selective harmonic elimination for cascaded multicell multilevel power converters with higher number of H-Bridge modules

This paper presents a curve fitting based method for generating suitable switching angles for selective line-to-line voltage harmonic elimination in cascaded multicell (CM) multilevel power converters. The selective harmonic elimination techniques derive feasible switching angles to eliminate the dominant low-order line-to-line voltage harmonics in a cascaded multicell multilevel power converter. In this paper, first the structure and operation of an eleven-level cascaded H-Bridge converter is reviewed and the general concept of selective harmonic elimination for this type of converter is studied briefly. Then, the proposed curve fitting based implementation method is presented. Finally, simulation results are provided to validate the proposed method.

Fuzzy adjustment of weighting factor in model predictive control of permanent magnet synchronous machines using current membership functions

One of the problems pertaining to model predictive control (MPC) of a motor drive system is choosing the weighting factors in the cost function. The prevalent approach to obtain the weighting factors is an empirical method. The weighting factors chosen by this method are always fixed and designed based on a single operating point. Therefore, the designed weighting factors are not suitable for the whole range of operation of the system. In this paper, a fuzzy based adaptive scheme for updating the weighting factors in a permanent magnet synchronous drive system is proposed to overcome this problem. Simulation and experimental results are provided to prove the effectiveness of the proposed method.

Three-dimensional finite-element-model investigation of axial-flux PM BLDC machines with similar pole and slot combination for electric vehicles

Axial-flux permanent-magnet brushless-dc (AFPM BLDC) machines with concentrated windings are very attractive choices for direct-drive applications due to their high torque-density, high efficiency, and extreme compact construction. Particularly they are suitable to be used in in-wheel electric vehicles. For this purpose two different AFPM BLDC machine topologies with similar pole and slot combination are designed, and cogging torque, winding inductance, output torque, and unbalanced torque exerted on bearing are obtained for the two 3.4 kW motors. High precision three-dimensional (3-D) finite-element analysis is used to achieve the performance of two motor topologies accurately.

Developing a hierarchical modular PV array model using PLECS block-set in MATLAB

This work elaborates on design of a Photovoltaic (PV) array model using Piecewise Linear Electrical Circuit Simulation (PLECS) block-set in Simulink. First it describes the model development procedure. Next it compares the I-V curves generated using the developed model with the experimental I-V curves of a HiS-M215SG reported in the product datasheet. Then it illustrates the use of the developed model for study of partial shading effect in a PV system.

Fault-tolerant operation of cascaded H-Bridge inverters using one redundant cell

This paper presents a fault-tolerant technique for multilevel Cascaded H-Bridge (CHB) inverters. A faulty power switch in high power converters can lead to expensive downtime, loss of productivity, and increased costs. In the event of a fault, the defective cell is bypassed and a backup H-Bridge cell is replaced to generate balanced line-to-line voltages. Using the remaining cells, CHB inverter will operate with maximum achievable output voltage. Simulation results are offered for a seven-level CHB inverter to validate the proposed fault-tolerant technique.

A new maximum power point tracking method for photovoltaic applications based on finite control set model predictive control

This paper proposes a new Maximum Power Point Tracking (MPPT) method based on the concept of Finite Control Set Model Predictive Control (FCS-MPC) for Photovoltaic (PV) applications. The proposed method uses the measured PV current and power data from previous steps to predict the power in the next step correspondent to various possible switching configurations of the power converter. Then it applies the switching configuration which results in increase in the produced power by the PV array. Simulation results are provided to verify operation of the proposed method and compare it with the traditional Perturb and Observe (P&O) method.

A fault-tolerant strategy based on Fundamental Phase Shift Compensation for three phase multilevel converters with quasi-Z-source networks

This paper proposes a new fault-tolerant strategy for a multilevel converter (MLC) with an integrated impedance-source network. The proposed fault-tolerant strategy leverages the flexibility provided by the impedance-source network to implement the Fundamental Phase Shift Compensation (FPSC) method in order to restore operation of a multilevel converter with one or more faulty switches to the pre-fault conditions. In this paper, first a brief review of CHB converters and the modulation method is provided. Then the proposed fault-tolerant scheme is introduced. Finally, the experimental results from a prototype converter are provided to validate the operation of the proposed strategy.