The disc coreless permanent magnet synchronous machine (PMSM) has many advantages. The inductance is far lower than that of the machines with the core structure. However, the general converter is designed for general machines. The current fluctuations are large when the low-inductance PMSM (LIPMSM) is driven by the general converter. To solve the above problem, the integrated design concept is adopted to design the converter, including the modulation algorithm, control algorithm, and the corresponding topology. The joint modulation strategy is proposed to increase the modulation frequency, which adjusts the output voltage by using the bus circuit and inverter circuit. The model predictive current control (MPCC) algorithm based on the joint modulation strategy is proposed, which has a small computational burden and high control accuracy. The most important feature of the proposed MPCC is that it has a modulation algorithm. To further reduce the current fluctuations, the bus voltage is adjusted in real time according to the bus voltage optimization algorithm. A new topology of the converter is designed to implement the algorithm function. Finally, the correctness and feasibility of the proposed method are verified. Compared with the general converter, the new one has a great improvement on the LIPMSM.

The mechanical optimization is critical for the high-speed permanent magnet synchronous machine (HSPMSM) due to its high-speed operating condition. The sensitivity analysis is necessary to improve mechanical strength and stiffness since various influencing factors. This paper presents a mechanical multi-objective optimal design of HSPMSM based on parametric sensitivity analysis. The parameters with marked influence on the rotor stress and critical speed are selected as the design varia-bles: including the material properties, length-diameter ratio, in-terference size, and bearing stiffness. The parametric sensitivity analysis is performed to provide the influencing magnitude and trend of each parameter. And the best combination of variable levels could be determined. The result shows the performance of the optimized design is improved greatly, which verifies the validity of the proposed optimization method. The sensitivity analysis of each influencing parameter provides guidance for HSPMSM efficient optimization.

Existing control methods for wireless power transfer (WPT) systems struggle to achieve zero-voltage switching (ZVS), output stability, and efficiency optimization at the same time. To address this problem, this letter proposes a hierarchical-constraint model predictive control (HCMPC) method by structuring the control into prioritized layers. HCMPC can achieve ZVS, output regulation, and efficiency optimization simultaneously without using complex weighting factors. Experimental results illustrate that HCMPC delivers an output voltage error below 0.5% and efficiency above 90% over a wide load range from 30 to 80 Ω. Under load transients, the settling times are 12 and 15 ms, respectively. Meanwhile, the WPT system can ensure ZVS for all switches in the whole load range. The proposed approach provides a robust and scalable solution for WPT systems, broadening their practical deployment in electric vehicles and consumer electronics products.

Dynamic Wireless Power Transfer (DWPT) is a pivotal technology for future mobile electrical energy interaction. However, its widespread adoption is challenged by significant transfer fluctuations induced by spatial and temporal factors. This paper proposes a vectorization method of variables to reconstruct the controlled scalar variables into space vector variables for analyzing fluctuations in both spatial and temporal factors. A vector-based model is further established for the multi-transmitter (Tx)-single-receiver (Rx) DWPT system. To improve the performance, the model is constrained and ultimately simplified into a single-Tx-single-Rx model. Based on this model, a stable output of the Rx is achieved just by maintaining the amplitude of the input voltage vector, which can track the Rx position synchronously. This paper further investigates the impact of the coil design parameters on the electrical parameters, cross‑coupling, fundamental content and offset of coupling coefficient curves, which can impact the model and system performance through the analysis. Compared with two existing advanced methods, the proposed approach demonstrates superior performance in experiments: power fluctuations remain around ±1.2% across all tested positions, and average efficiency exceeds 90%, peaking at 92.3%.