The interest in predictive control approach and multiphase drives has been steadily growing during the last decade. Predictive control techniques have been recently introduced as a viable alternative to conventional PI controllers with carrier-based or space vector PWM techniques in the current regulation of multiphase power converters and drives. The developed schemes have demonstrated a good performance at the expense of a high computational cost, an unknown switching frequency, and the appearance of large undesirable stator current harmonic components. In this paper, an enhanced predictive current control technique with fixed switching frequency is introduced for an asymmetrical dual three-phase ac drive. Fast torque and current responses are achieved while favoring stator current harmonic suppression. The experimental results are provided to verify the benefits of the proposed control method when compared to the other existing predictive control methods.

Predictive control techniques have recently been applied with success to conventional and multiphase electrical drives. The additional degrees of freedom in multiphase drives make the real-time implementation of optimal solutions difficult due to the increased number of iterations. This paper proposes a predictive control technique that reduces the available voltage source inverter switching states according to predefined constraints. The introduced method, called as restrained search predictive control, favors on-line implementation and improves the current tracking performance. Simulation and experimental results are provided to test the viability of the presented technique.

The growing interest in multiphase electrical drives has required the extension of control schemes and modulation techniques already well known for three-phase drives. Specifically, different and more complex space-vector pulse width modulation (SVPWM) methods have been developed for multiphase machines taking into account the increased number of switching possibilities and the new components resulting from generalized Clarke's transformation. In spite of the intensive work undertaken in the last decade, no SVPWM techniques with common-mode voltage (CMV) reduction have been developed for five-phase drives. This work proposes two SVPWM methods that are capable of reducing the peak-to-peak CMV by 40% and 80% compared to standard five-phase modulation strategies. Reduction of the CMV is done at the expense of higher phase voltage and current distortion. Simulation and experimental results confirm the CMV reduction and quantify the performance penalties of the proposed methods.

This paper reports on flux harmonic distortion factor and current ripple analysis for various discontinuous pulse-width-modulation (PWM) techniques, which are applicable in conjunction with five-phase two-level inverter-fed induction motors. The analysis is based on the application of the complex space vector approach. The results are compared throughout with the corresponding continuous PWM techniques. Different space vector PWM and carrier-based PWM methods are encompassed by the analysis. This paper is supported by extensive simulation results. Verification of theoretical findings is provided through experimental measurements on a five-phase induction motor.

The common-mode voltage (CMV) is known to be a source of electromagnetic interference, and it is potentially dangerous for the machine windings' insulation and bearings. CMV has been analyzed for three-phase machines supplied by voltage-source inverters, showing that modified pulsewidth modulation and model predictive control (MPC) techniques can significantly reduce the CMV at the expense of increased current distortion. This paper analyzes the CMV for five-phase drives and proposes a modified MPC strategy that accounts for the CMV reduction. The MPC can adjust the weights of the cost function to find a good balance between CMV reduction and low current distortion. The MPC strategy is experimentally tested showing how the CMV can be effectively reduced, thus improving the multiphase drive performance.

This study presents a space vector pulsewidth modulation algorithm for five-phase converters operating in the overmodulation region that forbids the use of zero vectors, covering the whole overmodulation range and providing minimum x-y voltages. Avoiding zero vectors reduces the content of low-order current harmonics and, at the same time, reduces the common-mode voltage (CMV) by 40%. The method is first implemented using medium and large voltage space vectors, showing good performance in terms of current harmonic content. Then, the algorithm is applied to the case when four large vectors are used, further reducing the peak-to-peak CMV by 80% and still demonstrating a satisfactory performance. Both methods are experimentally compared to existing overmodulation algorithms obtaining better current quality and lower peak-to-peak CMV.