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In this paper, a simplified active islanding detection method based on a power control disturbance signal for a three-phase grid-connected inverter application is presented. The disturbance and observation method is used to simplify the significant indicator, which determines the islanding condition. The control algorithm, which is used to command the observation and disturbance method, is derived from a three-phase grid-connected inverter. The power is easily transferred to the grid by converting it to direct current (DC) and commanding it on the rotating reference frame. The d-axis current command represents the active power, and the q-axis current command represents the reactive power. The power disturbance signal is performed by d-axis harmonic current injection. At the transforming point of common coupling (PCC), the DC component of the harmonic voltage signal can be easily observed by applying a Park transform. The IEEE Std. 1547 is applied to qualify the power-quality guarantee and anti-islanding test requirements. The validity of this approach was confirmed by simulation and experimental results. [ABSTRACT FROM AUTHOR]

A design of a Class-E inverter with only one inductor and one capacitor is presented. It is operated at the optimal operation mode for domestic cooker. The design principle is based on the zero-voltage derivative switching (ZVDS) of the Class-E inverter with a parallel load network, which is a parallel resonant equivalent circuit. An induction load characterization is obtained from a large-signal excitation test bench, which is the key to an accurate design of the induction cooker system. Consequently, the proposed scheme provides a more systematic, simple, accurate, and feasible solution than the conventional quasi-resonant inverter analysis based on series load network methodology. The derivative of the switch voltage is zero at the turn-on transition, and its absolute value is relatively small at the turn-off transition. Switching losses and noise are reduced. The parameters of the ZVDS Class-E inverter for the domestic induction cooker must be selected properly, and details of the design of the components of this Class-E inverter need to be addressed. A 1,200 W prototype is designed and evaluated to verify the validation of the proposed topology. [ABSTRACT FROM AUTHOR]

An analysis of the junction capacitance in resonant rectifiers which has a significant impact on the operating point of resonance circuits is studied in this paper, where the junction capacitance of the rectifier diode is to decrease the resonant current and output voltage in the circuit when compared with that in an ideal rectifier diode. This can be represented by a simplified series resonant equivalent circuit and a voltage transfer function versus the normalized operating frequency at varied values of the resonant capacitor. A low voltage to high voltage push-pull DC/DC resonant converter was used as a design example. The design procedure is based on the principle of the half bridge class-DE resonant rectifier, which ensures more accurate results. The proposed scheme provides a more systematic and feasible solution than the conventional resonant push-pull DC/DC converter analysis methodology. To increase circuit efficiency, the main switches and the rectifier diodes can be operated under the zero-voltage and zero-current switching conditions, respectively. In order to achieve this objective, the parameters of the DC/DC converter need to be designed properly. The details of the analysis and design of this DC/DC converter's components are described. A prototype was constructed with a 62-88 kHz variable switching frequency, a 12 VDC input voltage, a 380 VDC output voltage, and a rated output power of 150 W. The validity of this approach was confirmed by simulation and experimental results. [ABSTRACT FROM AUTHOR]

This paper presents the use of a novel, single-stage high-power-factor electronic ballast with a symmetrical class-DE low-dv/dt resonant rectifier as a power-factor corrector for fluorescent lamps. The power-factor correction is achieved by using a bridge rectifier to utilize the function of a symmetrical class-DE resonant rectifier. By employing this topology, the peak and ripple values of the input current are reduced, allowing for a reduced filter inductor volume of the EMI filter. Since the conduction angle of the bridge rectifier diode current was increased, a low-line current harmonic and a power factor near unity can be obtained. A prototype ballast, operating at an 84-kHz fixed frequency and a 220-Vrms, 50-Hz line input voltage, was utilized to drive a T8-36W fluorescent lamp. Experimental results are presented which verify the theoretical analysis. [ABSTRACT FROM AUTHOR]