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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]

This paper presents a simplified control technique for a dual three-phase topology of a unified power quality conditioner—iUPQC. The iUPQC is composed of two active filters, a series active filter and a shunt active filter (parallel active filter), used to eliminate harmonics and unbalances. Different from a conventional UPQC, the iUPQC has the series filter controlled as a sinusoidal current source and the shunt filter controlled as a sinusoidal voltage source. Therefore, the pulse width modulation (PWM) controls of the iUPQC deal with a well-known frequency spectrum, since it is controlled using voltage and current sinusoidal references, different from the conventional UPQC that is controlled using nonsinusoidal references. In this paper, the proposed design control, power flow analysis, and experimental results of the developed prototype are presented. [ABSTRACT FROM PUBLISHER]

This paper presents a regenerative step-up/step- down dc-dc zero-voltage-switching pulsewidth-modulation converter with active clamping. The switch losses are reduced due to the implementation of a simple active snubber circuit that provides soft commutation in all the switches of the converter. The theoretical analysis, basic equations, design methodology, and experimental results are shown in this paper. A control methodology to assure the output voltage regulation is also proposed. The main advantages of the proposed power converter are the small number of components, simplicity of the controller, robustness, small weight and size, and high efficiency. [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]