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Treatment of wastewater using ultrasound systems is gaining increasing interest due to its effectiveness for a wide range of pollutants and no secondary pollutant production. This paper proposes two ultrasound systems operating at different ranges of electrical power and frequency developed to remove toxic polycyclic aromatic hydrocarbon (PAH) compounds in wastewater. Both light molecular weight (LMW) and high molecular weight (HMW) compounds were degraded using the developed systems. However, HMW compounds were more affected. The experimental results revealed that treatment at a high power level is not always a proper approach for a large reduction of PAH compounds. Whereas treatment at higher frequencies and lower power can be a suitable alternative to enhance the PAHs removal rate and the system energy efficiency and reduce losses. Therefore, a dual‐mode ultrasound system with adjustable operating frequency and power is a promising approach for the treatment of industrial wastewater containing toxic PAH compounds. [ABSTRACT FROM AUTHOR]

Non-linear rectifier loads usually cause heavy distortion in the output voltage of single-phase inverters due to pulsating charging current of the rectifier direct current link capacitor. In this article, a predictive load current-based digital feedforward (PCFF) compensation method is proposed to decrease the inverter voltage distortion associated with the pulsating load current. PCFF control scheme works along with the basic inverter control structure that consists of a repetitive controller and a synchronous reference frame PI controller. The PCFF method further improves the single-phase inverter performance by enhancing its compensation dynamics. The simulation and experimental results show that the proposed control strategy can effectively reduce the total harmonics distortion of the inverter voltage and improve the output voltage quality. [ABSTRACT FROM AUTHOR]

Double switching frequency components of the input current in the isolated three-port converter (TPC) can be effectively mitigated using an LC circuit at the input side of the converter. Although the LC circuit prevents the high-frequency current flow into the system, there is a resonant peak in the port current control model that can degrade the control performance and even give rise to instability issues. In this article, an active damping method (ADM) is proposed to enhance the damping ratio of the current control system and decrease the resonance amplitude of the LC circuit. The proposed ADM is fully implemented within the converter control system without any additional circuits or components and as such is seen as a costeffective and efficient method. Simulation and experiment results show the effectiveness of the proposed method on the input current oscillation elimination in an isolated TPC. [ABSTRACT FROM AUTHOR]

Double-switch buck–boost converter is a distinctly suitable candidate for the front-end converter in two-stage power converter systems that can perform step-up/down power conversion. Several modulation schemes, such as synchronisation modulation (SM), interleaved modulation (IM) and combined control strategy have been proposed for this converter, and these methods yield notable advantages in different aspects, such as amplitude of inductor ripple current, conversion efficiency, power density and so on. However, the requirements of the converter are not only limited in the aforementioned metrics, but the related complexity of control system design, implementation and control performance sometimes also play important roles in industry applications. A novel modulation scheme is proposed in this study to obtain a balanced performance in terms of ripple/average current of the inductor, and to operate along with a model based control system and finally, the conversion efficiency is compared to the SM and IM modulation methods. Experimental results are presented to demonstrate the effectiveness of the proposed modulation method. [ABSTRACT FROM AUTHOR]

Power supplies with several paralleled DC/DC converters are usually used for high reliability purposes owing to their advantage in terms of redundancy and modularisation. However, current unbalance due to parameter deviations among the paralleled converters might deteriorate the whole system reliability and results in excessive thermal and device stress in some individual modules. In this study, an equivalent transfer function derived from the output impedance and the voltage control loop gain. Also, a loop-shaping based robust control method is employed to design a current sharing controller utilising the proposed transfer function. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed method for the parallel DC/DC converter performance improvement. [ABSTRACT FROM AUTHOR]