Multiphase motor drives offer better advantages in high-power motion control applications as they can handle more power with reduced power per phase, lower-order harmonics, reduced input filter size, etc., compared to the classical 3-phase (Φ) systems. The symmetrical 6-Φ voltage source inverter (VSI)-fed interior permanent magnet synchronous motor (IPMSM) drive controlled by the conventional space vector pulse width modulation (SVPWM) results in different common mode voltage (CMV) levels. This rate of change of CMV is responsible for the flow of the common mode (CM) current, which can lead to premature bearing damage in motor loads. To circumvent this problem, this paper proposes two new SVPWM-based PWM variants for the symmetrical 6-Φ VSI drive that are aimed at attaining a constant CMV level, thereby completely avoiding the changes in CMV. The proposed PWM variants are designed in such a way that they closely mimic the 3-Φ SVPWM principle, making the implementation of SVPWM for the 6-Φ VSI very simple and thus decreasing the complexity of dwell time calculations for the 6-Φ VSI system. Detailed simulation studies using MATLAB/Simulink are presented to support the proposed PWM variants with vector control implemented under speed and load disturbances, including speed reversal following V/f control.

For large-scale energy storage applications, variable-speed pumped hydro storage plants (VS-PHSP) are a proven solution due to their fast start-up and high ramping capabilities. Variable-speed operation is primarily dependent on power electronic converters. However, existing converter topologies often suffer from drawbacks, including a large number of semiconductor devices, the need for series-connected switches, and non-uniform voltage distribution, which result in increased losses, complex cooling requirements, and overall system cost. To overcome these challenges, this paper proposes a back-to-back configuration of a new four-level converter for VS-PHSP systems. The proposed topology eliminates the requirement for series device connections and ensures uniform voltage sharing among switches. Subsequently, it reduces the overall device count and their cost. In addition, a model predictive control for the proposed back-to-back configuration is implemented and validated through MATLAB simulations.

The main issues impeding wide adoption of electric vehicles (EVs) are limited driving range and longer battery charging time. Recently, there has been a shift from traditional 400 V battery charging systems (BCS) to next-generation 800 V BCS owing to advantages such as reduced battery charging time and weight savings in the EVs. The dual active bridge (DAB) converter and resonant converters are typically used in the isolated bidirectional dc-dc conversion stage (IBDCS) in EVs. Among which DAB converter is a popular choice because of simplicity in control, inherent bidirectional power flow and soft-switching capability. The performance of the conventional DAB topology however gets compromised when operating over such a wide battery voltage range. This paper proposes a reconfigurable DAB (r-DAB) converter for the IBDCS of EV charging infrastructure to cater to the wide voltage range requirements of traditional/next-generation of EVs. Besides, the proposed r-DAB converter facilitates bidirectional power flow capability that can support the grid during peak load demands. In this paper, the operational aspects and the control structure of the proposed r-DAB converter are analyzed in detail and the same are validated through PLECS simulations.

Three level voltage space vector can be generated using the cascaded three-level inverter comprising of two, two-level inverters. Traditionally, this circuit demands two isolated DC power sources to power the individual two-level inverters. This paper proposes a new carrier-modified pulsewidth modulation (PWM) method for the cascaded three-level inverter that involves modifying the carrier signals using suitable offset-voltage in place of the commonly used approach that involves modifying the reference signals. The neutral-point current, the capacitor voltages and the deviation in the capacitor voltages are carefully studied and based on the studies, suitable offset-voltage to be injected to the carriers is determined that is dependent on the DC-link capacitor voltage deviations. It also presents equivalence of the proposed modified-carrier PWM with the traditional CBPWM that involves voltage-injection to the modulating signals. The envisaged carrier-modified PWM method obviates the need of two isolated power sources and thus enables the cascaded three-level inverter to be operate from a single DC power source. The efficacy of the proposed carrier-modified PWM method for the single DC source driven cascaded three-level inverter drive is demonstrated through simulations and experiments by running the induction motor load over a wide speed range. Besides, superior load current performance is also achieved with the proposed PWM method that is supported from vWTHDprofiles.

Permanent Magnet Assisted Synchronous Reluctance Motors (PMaSynRMs) are emerging as viable alternative to PMSMs, particularly in applications where cost and material availability are critical. Rotor geometry and magnet placement pose challenges and can be effectively handled through design optimization for improved motor performance. The process of improving motor performance through FEA simulations using multi-objective optimization is complex and time-consuming. This paper proposes a new motor design approach to improve the performance of a PMaSynRM with minimal computational cost by using Kriging surrogate modeling integrated with the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II). Initially, the critical rotor parameters influencing the performance characteristics of PMaSynRM, such as torque, torque ripple, and saliency, are identified. These parameters are sampled within their bounds using a five-level Taguchi orthogonal array, ensuring a balanced exploration of factor levels. A design of experiments (DOE) is carried out using these samples and the resulting responses are regarded as true responses. A Kriging surrogate model is also created with these samples to predict the responses and its accuracy is validated against the true responses. To demonstrate the effectiveness of the proposed optimization approach, this paper presents the design of a 1.5 kW, 36-slot 6-pole PMaSynRM with a fluid flux barrier rotor. The proposed design approach achieves an improvement in rotor saliency by 2.5 times and torque ripple reduction by 6.3 % compared to one of the recent works.