Voltage controllable power factor corrector based inductive coupling power transfer system

Abstract

This paper proposed a novel inductive coupling power transfer (ICPT) topology to improve the power factor, output voltage regulation and efficiency. The proposed ICPT is mainly constructed by a voltage controllable power factor corrector (VC-PFC) and a LLC resonant circuit. Additionally, the series compensation and series-parallel compensation are used in the primary and the secondary sides of the coupling transformer to increase the coupling efficiency and the load range. Finally, the circuit simulation of the proposed ICPT is presented to verify the performance. Simulation results show that under the 10 mm coupling distance, the power factor correction and output voltage regulation can be achieved at the same time.

Single-phase five-level inverter with less number of power elements for grid connection

Abstract

Recently, the emergence of single phase multilevel inverter has been increased due to its advantages over traditional one. This paper proposes a single-phase five level pulse width modulation (PWM) inverter for grid connection employing PI controller to perform unity power factor. Two triangular carrier signals identical to each other with an offset equivalent to the amplitude of the reference signal were used to generate PWM signals for the switches. The proposed inverter has the advantage of less number of components. Operational principles with switching functions are analyzed. A digital proportional integral current control algorithm is implemented in FPGA XC3S400 to control the injected current into the grid to be almost sinusoidal. The inverter offers much less total harmonic distortion and can operate at near-unity power factor. Some switches operate at fundamental frequency and others operate at switching frequency. The proposed inverter has been compared with the conventional single-phase five-level PWM inverter. The effectiveness of the proposed inverter and its control technique has been verified theoretically, using PSIM simulation program, and experimentally, using laboratory prototype system.

Practical Design and Implementation Procedure of an Interleaved Boost Converter Using SiC Diodes for PV Applications

Abstract

The implementation of an interleaved boost converter (IBC) using SiC diodes for photovoltaic (PV) applications is presented in this paper. The converter consists of two switching cells sharing the PV panel output current. Their switching patterns are synchronized with 180° phase shift. Each switching cell has a SiC Schottky diode and a CoolMOS switching device. The SiC diodes provide zero reverse-recovery current ideally, which reduces the commutation losses of the switches. Such an advantage from the SiC diodes enables higher efficiency and higher power density of the converter system by reducing the requirement of the cooling system. This paper presents also an optimization study of the size and efficiency of the IBC. Based on 1) the steady-state characteristic of the topology; 2) the static and dynamic characteristics of the switching cells; 3) the loss model of the magnetic components; and 4) the cooling system design, the paper provides a set of design criteria, procedures, and experimental results for a 2.5 kW IBC prototype using SiC diodes.

New approaches for Harmonics reduction in solar inverters

Abstract

This paper analyzes and compares two approaches for dc to ac power conversion. First approach uses cascaded H-Bridge Inverter and second uses new Multi-level Scheme having Level Modules and H-Bridge. The simulation is done in SIMULINK/ MATLAB Software. The Total Harmonic Distortion in output load voltage, active Power and reactive Power produced by both the approaches are compared. It is shown that THD produced in second scheme is better up to a certain stages of the first scheme. And the available active and reactive powers are larger for the second scheme.

Interleaved Buck Converter Having Low Switching Losses and Improved Step-Down Conversion Ratio

Abstract

This paper proposes a new interleaved buck converter (IBC) having low switching losses and improved step-down conversion ratio, which is suitable for the applications where the input voltage is high and the operating duty is below 50%. It is similar to the conventional IBC, but two active switches are connected in series and a coupling capacitor is employed in the power path, such as Cuk, Sepic, and Zeta converters. The proposed IBC shows that since the voltage stress across all the active switches is half of the input voltage before turn-on or after turn-off when the operating duty is below 50%, the capacitive discharging and switching losses can be reduced considerably. This allows the proposed IBC to have higher efficiency and operate with higher switching frequency. In addition, the proposed IBC has a higher step-down conversion ratio and a smaller output current ripple compared with a conventional IBC. The features, operation principles, and relevant analysis results of the proposed IBC are presented in this paper. The validity of this study is confirmed by the experimental results of prototype converters with 150-200 V input, 24 V/10 A output.