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This paper proposes a common-mode electromagnetic interference (CM-EMI) spectrum calculation method based on double Fourier series for photovoltaic (PV) inverters with chaotic sinusoidal pulsewidth modulation (CSPWM). In this paper, the CM-EMI of a single-phase PV inverter is first analyzed, and the equivalent circuit of the CM-EMI in the single-phase PV inverter is established, then the CSPWM is employed to suppress the CM-EMI in PV inverters. Moreover, the proposed EMI spectrum calculation method based on double Fourier series is applied in evaluating the CM-EMI spectrum of the single-phase PV inverter. Finally, the simulation and experimental results validate the EMI suppression effectiveness of the CSPWM and the correctness of the proposed EMI spectrum calculation method. Therefore, the proposed EMI spectrum calculation method provides a theoretical support for CSPWM to reduce EMI. [ABSTRACT FROM AUTHOR]

This paper introduces the periodic carrier frequency modulation (PCFM) for permanent magnet synchronous motor (PMSM) drive systems so as to reduce the low-frequency electromagnetic interference (EMI). PMSMs are widely used in many applications and they are usually fed by pulsewidth modulation (PWM) inverters. The EMI of PMSM, which results from the switch of power device, generates undesirable effects on the control system. Therefore, it is of importance to reduce the EMI of PMSM. The common mode (CM) conducted EMI model of the PMSM drive system is constructed to investigate the CM voltage. The simulations and experiments of PMSM fed by the fixed frequency PWM (FFPWM) and PCFM are implemented to analyze the CM conducted EMI. The CM EMI spectra of PMSM fed by the FFPWM and PCFM with different spreading frequency widths are compared to explore the influence of PCFM on the CM conducted EMI. The regular patterns on PCFM in reducing the CM conducted EMI of PMSM drive systems are revealed. [ABSTRACT FROM AUTHOR]

This paper proposes a novel cableless magnetic actuator with a new propulsion module that exhibits a very high thrusting force and is capable of locomotion in a thin pipe by means of a new motion principle. The magnetic actuator is moved according to the vibration amplitude and elastic energy of a mass-spring system due to mechanical resonance energy. The proposed actuator contains an electrical inverter that directly transforms dc from button batteries into ac. The electrical dc–ac inverter incorporates a mass-spring system, a reed switch, and a curved permanent magnet that switches under electromagnetic force. Experimental results reveal that the actuator is able to move upward at a speed of 52 mm/s when powered by 10-button batteries and pulling a load mass of 10 g. [ABSTRACT FROM AUTHOR]