A common-mode (CM) filter based on the LCL filter topology is proposed in this paper, which provides a parallel path for ground currents and which also restricts the magnitude of the EMI noise injected into the grid. The CM filter makes use of the components of a line to line LCL filter, which is modified to address the CM voltage with minimal additional components. This leads to a compact filtering solution. The CM voltage of an adjustable speed drive using a PWM rectifier is analyzed for this purpose. The filter design is based on the CM equivalent circuit of the drive system. The filter addresses the adverse effects of the PWM rectifier in an adjustable speed drive. Guidelines are provided on the selection of the filter components. Different variants of the filter topology are evaluated to establish the effectiveness of the proposed circuit. Experimental results based on EMI measurement on the grid side and the CM current measurement on the motor side are presented. These results validate the effectiveness of the filter.

Lithium-ion (Li-ion) batteries have been competitive in Electric Vehicles (EVs) due to their high energy density and long lifetime. However, there are still issues, which have to be solved, related to the fast-charging capability of EVs. The pulsed current charging technique is expected to improve the lifetime, charging speed, charging/discharging capacity, and the temperature rising of Li-ion batteries. However, the impact of the pulsed current parameters (i.e., frequency, duty cycle, and magnitude) on characteristics of Li-ion batteries has not been fully understood yet. This paper summarizes the existing pulsed current modes, which are positive Pulsed Current Mode (PPC) and its five extended modes, and Negative Pulsed Current (NPC) mode and its three extended modes. An overview of the impact of pulsed current techniques on the performance of Li-ion batteries is presented. Then the main impact factors of the PPC strategy and the NPC strategy are analyzed and discussed. The weight of these impact factors on lifetime, charging speed, charging/discharging capacity, and the temperature rising of batteries is presented, which provides guidance to design advanced charging/discharging strategies as well as to determine future research gaps.

The modular structure and the many other advantages of the Modular Multilevel Converter makes it an attractive converter for Battery Energy Storage Systems, allowing the battery units to be distributed throughout the convert, connected in each submodule. However, such an arrangement results in large oscillating components in the battery current, which is harmful to battery performance and lifetime. In most literature this is solved using DC-DC converters as active interfaces between battery and submodule. This paper investigates a passive filter arrangement as an alternative solution to the DC-DC converters. Where the batteries are interfaced with the submodules using a passive filter that suppresses the fundamental component and control technique that injects circulating current to suppress second harmonic component. It is concluded that this passive technique could be an attractive solution especially where high reliability is of concern.

In this paper, a control method is proposed that allows the extraction of maximum power from each individual photovoltaic string connected to the Modular Multilevel Converter (MMC) and inject balanced power to the AC grid. The MMC solution used does not need additional DC–DC converters for the maximum power point tracking. In the MMC, the photovoltaic strings are connected directly to the sub-modules. It is shown that the proposed inverter solution can provide balanced three-phase output power despite an unbalanced power generation. The maximum power of the photovoltaic string is effectively harnessed due to the increased granularity of the maximum power point tracking. An algorithm that tracks the sub-module capacitor voltages to their respective voltage references is proposed. A detailed modeling and control method for balanced operation of the proposed topology is discussed. The operation of the MMC under unbalanced power generation is discussed. Simulation results are provided that show the effectiveness of the proposed control under unequal irradiance.

Modern PWM inverter output voltage has high dv/dt, which causes problems such as voltage doubling that can lead to insulation failure, ground currents that results in electromagnetic interference concerns. The IGBT switching device used in such inverter are becoming faster, exacerbating these problems. This paper proposes a new procedure for designing the LC clamp filter. The filter increases the rise time of the output voltage of inverter, resulting in smaller dv/dt. In addition suitable selection of resonance frequency gives LCL filter configuration with improved attenuation. By adding this filter at output terminal of inverter which uses long cable, voltage doubling effect is reduced at the motor terminal. The design procedure is carried out in terms of the power converter based per unit scheme. This generalizes the design procedure to a wide range of power level and to study optimum designs. The effectiveness of the design is verified by computer simulation and experimental measurements.