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The distributed power generation system (DPGS) with renewable energy sources is gaining popularity over conventional sources of energy. Although the renewable sources of energy are available in abundance and are eco‐friendly, yet, they have intermittent nature. As a result, renewable energy‐based DPGS face difficulty in power transfer during adverse atmospheric conditions. Also, if the interfacing unit is a single inverter, its switches have to withstand a large amount of heat and handle a high value of current. Henceforth, to ensure uninterrupted supply and reduce voltage stress on switches, the power inverters need to be connected in parallel. This study presents various current and power‐sharing control strategies of parallel‐interfaced voltage source inverters with a common AC bus. A detailed classification and analysis of wired and wireless (droop) controllers for parallel‐connected voltage source inverters have been done. Moreover, the recent trends and improvements in traditional droop controllers are presented. Finally, a comparative analysis among the various wired and wireless controllers is done, listing their advantages and limitations. [ABSTRACT FROM AUTHOR]

In the case of unbalanced load performance, the key issue in speed control of a single inverter-powered parallel motor coupling system is how to overcome the difference in motor parameters and the effect of slip between the induction motors to maintain the same speed. Based on the synergetic control theory and synergy manifold design techniques, the model which is field-oriented vector control with reduced order induction is proposed, as well as a synergetic control strategy. Moreover, the accuracy of the rotor flux observation is one of the most important steps in the motor control. In order to improve the convergence speed of rotor flux error, a new flux observer based on the sliding mode theory is proposed. Introducing the Sig function instead of the symbol function, the sliding mode control technology is improved to observe rotor to eliminate the control chattering. Then, two motor speed coupling weighted synergetic control models are given by using the new weight vector of the parallel induction motor. These models can directly obtain the stator excitation current and torque current of the two motors. The simulation and experimental results show that the newly proposed motor synergetic control method has better steady operation performance, overcomes the shortcomings of the existing average vector control method in load imbalance and motor parameter difference and proves the validity and advancement of the design strategy. [ABSTRACT FROM AUTHOR]

In wireless charging devices, a transmitter that applies a single inverter to output dual-frequency can effectively solve the charging incompatibility problem caused by different wireless charging standards and reduce the equipment volume. However, it is very difficult to solve the switching angle of the modulated dual-frequency waveform, which involves non-linear high-dimensional multi-objective optimization with multiple constraints. In this paper, an improved differential evolution (DE) algorithm is proposed to solve the transcendental equations of switching angle trains of dual-frequency programmed harmonic modulation (PHM) waveform. The proposed algorithm maintains diversity while preserving the elites and improves the convergence speed of the solution. The advantage of the proposed algorithm was verified by comparing with non-dominated sorting genetic algorithm II (NSGA II) and multi-objective particle swarm optimization (MOPSO). The simulation and experimental results validate that the proposed method can output dual-frequency with a single inverter for wireless power transfer (WPT).

This paper presents the control method for mono inverter dual parallel (MIDP) surface-mounted permanent-magnet synchronous motor (SPMSM) drive system. Unlike the MIDP induction machine drive system, MIDP SPMSM drive system suffers from the inherent instability due to the lack of slip. The proposed active damping control method refrains the system oscillation coming from the mechanical and electrical unbalances and enables the stable operation. This paper also presents the simple maximum torque per ampere control method for MIDP SPMSM drive system. Mathematically calculated optimal currents reduce the amplitude of the currents and improve the drive efficiency. To maximize the merits of the MIDP motor drive system, a sensorless algorithm is also applied. Experiments with the 600-W SPMSMs are executed to verify the feasibility of the proposed control method. [ABSTRACT FROM PUBLISHER]

Aiming at the decouple operating of double Y shift 30° permanent magnet synchronous motor ( PMSM) series-connected system driven by generalized zero-sequence harmonic,the Fourier transform expressions of double Y shift 30° PMSM concentrated winding function are setup,and the magneticmotive force( MMF) expressions of couple relation between the series-connected two motor are achieved. The influence laws of high order space harmonic of PMSM on decouple operating for the series-connected system were researched. The multi-dimension space mathematic models of PMSM1 containing 5th and 7th harmonics were setup. The simulating analysis of variable speed and variable loads was proposed,which shows the couple effects of the 5th and 7th space harmonics. The essential requirement of stator winding design for the series-connected system decouple control was revealed. [ABSTRACT FROM AUTHOR]

To improve the control performance of unbalanced load of parallel-connected dual induction motors fed by a single inverter, a novel control strategy based on the weighted vector control is proposed. In this paper, a weighted flux linkage vector model of dual induction motors is developed, and then the control expressions of weighted rotor flux linkage and summation torque of dual speed-irrelevant motors are derived. The weight value of vector control for dual induction motors in unbalanced load is distributed automatically according to the torques and motor speeds. The experimental results in multiple induction motor platforms prove that the proposed method can start in a wide load range, especially at heavy unbalanced load and improves the performance of dynamic response with a sudden change of unbalanced load. [ABSTRACT FROM AUTHOR]

In wireless charging devices, a transmitter that applies a single inverter to output dual-frequency can effectively solve the charging incompatibility problem caused by different wireless charging standards and reduce the equipment volume. However, it is very difficult to solve the switching angle of the modulated dual-frequency waveform, which involves non-linear high-dimensional multi-objective optimization with multiple constraints. In this paper, an improved differential evolution (DE) algorithm is proposed to solve the transcendental equations of switching angle trains of dual-frequency programmed harmonic modulation (PHM) waveform. The proposed algorithm maintains diversity while preserving the elites and improves the convergence speed of the solution. The advantage of the proposed algorithm was verified by comparing with non-dominated sorting genetic algorithm II (NSGA II) and multi-objective particle swarm optimization (MOPSO). The simulation and experimental results validate that the proposed method can output dual-frequency with a single inverter for wireless power transfer (WPT). [ABSTRACT FROM AUTHOR]