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This paper presents a zero-voltage (pulsewidth modulation) half-bridge inverter with active voltage clamping using only a single auxiliary switch. The structure is particularly simple and robust. It is very attractive for single-phase high-power applications. Switching losses are reduced due to implementation of the simple active snubber circuit that provides zero-voltage-switching conditions for all switches, which includes the auxiliary one. Its main features are simple modulation strategy, robustness, low weight and volume, low harmonic distortion of the output current, and high efficiency. The principle of operation for steady-state conditions, mathematical analysis, and experimental results from a laboratory prototype are presented. [ABSTRACT FROM AUTHOR]

• Voltage regulation using combined active and reactive power. • Control algorithm for active energy minimization in voltage regulation. • A comparative analysis performed on a battery energy storage system. The voltage drop affecting consumers at the end of distribution lines is one of the problems regarding power quality. The solutions applied to transmission lines are not fully effective in distribution lines, where line parameters are significantly high. In low-voltage distribution network, the reactive power compensation method is not as effective as active and reactive power compensation. This effect occurs on lines where the significant series resistance becomes remarkable in relation to the total line impedance. This paper presents the design and implementation of a four-wire, three-phase voltage source converter (VSC) with output current control for voltage regulation at the point of common coupling (PCC), using active and reactive power injection. A reactive power prioritization and minimization of active power strategy is proposed to overcome the problem of distribution line parameters. Digital design methodology is used to design the management controllers and loops, and a digital signal controller (DSC) is used for the entire implementation. The mathematical analysis results are validated using numerical simulation and proven with the construction of a 3.8 kVA prototype. The results showed that the converter accomplished an effective voltage regulation at the PCC with reduced active power. [ABSTRACT FROM AUTHOR]

This paper proposes an energy regeneration circuit for three-phase voltage-fed inverters using a modified Undeland snubber. The proposed system uses a quasi-square-wave zero voltage switching dc–dc auxiliary converter to regenerate the energy from snubber capacitor to the dc bus. The regenerative circuit uses a single active switch, and it operates independently of the three-phase inverter. Operation stages, theoretical waveforms, and a design methodology are presented. Experimental results based on a 4.5-kVA three-phase inverter prototype are included to validate the proposed topology. [ABSTRACT FROM PUBLISHER]

Voltage profile is one of many aspects that affect power quality in low-voltage distribution feeders. Weak grids have a typically high line impedance which results in remarkable voltage drops. Distribution grids generally have a high R/X ratio, which makes voltage regulation with reactive power compensation less effective than in high-voltage grids. Moreover, these networks are more susceptible to unbalance and harmonic voltage disturbances. This paper proposes an enhanced coordinated control of active and reactive power injected in a distribution grid for voltage regulation. Voltage drop mitigation was evaluated with power injection based on local features, such loads and disturbances of each connection. In order to ensure disturbances rejection like harmonic components in the grid voltages, a repetitive vector-control scheme was used. The injection of coordinated active and reactive power with the proposed control algorithm was verified through simulations and experiments, demonstrating that it is a promising alternative for voltage regulation in weak and low-voltage networks subject to inherent harmonic distortion. [ABSTRACT FROM AUTHOR]