High-Efficiency Single-Phase Transformerless PV H6 Inverter With Hybrid Modulation Method

Abstract—

The main contribution of this paper is the derivation rules summarized from existing high-performance inverters with H6-type configuration, which makes novel topologies possible. In addition, a novel high-efficiency single-phase transformerless photovoltaic inverter with hybrid modulation method is also proposed and evaluated as an example. Without input split capacitors, common-mode voltage and leakage current issues in a nonisolated system with H6-type configuration are eliminated, and the feature of a three-level output voltage in the inverter bridge’s middle point helps inductors and power quality optimization. The detailed operation principles with hybrid modulation strategy combined with unipolar and bipolar pulsewidth modulation schemes are presented. Experimental results of a 2200VA prototype verify the proposed topology with hybrid modulation method.

An Adjustable-Speed PFC Bridgeless Buck–Boost Converter-Fed BLDC Motor Drive

Abstract—

This paper presents a power factor corrected (PFC) bridgeless (BL) buck–boost converter-fed brushless direct current (BLDC) motor drive as a cost-effective solution for low-power applications. An approach of speed control of the BLDC motor by controlling the dc link voltage of the voltage source inverter (VSI) is used with a single voltage sensor. This facilitates the operation of VSI at fundamental frequency switching by using the electronic commutation of the BLDC motor which offers reduced switching losses. A BL configuration of the buck–boost converter is proposed which offers the elimination of the diode bridge rectifier, thus reducing the conduction losses associated with it. A PFC BL buck–boost converter is designed to operate in discontinuous inductor current mode (DICM) to provide an inherent PFC at ac mains. The performance of the proposed drive is evaluated over a wide range of speed control and varying supply voltages (universal ac mains at 90–265 V) with improved power quality at ac mains. The obtained power quality indices are within the acceptable limits of international power quality standards such as the IEC 61000-3-2. The performance of the proposed drive is simulated in MATLAB/Simulink environment, and the obtained results are validated experimentally on a developed prototype of the drive.

A Novel Variable-Speed Wind Energy System Using Induction Generator and Six-Switch ACIAC Converter

Abstract-

Nowadays using of the wind energy has a growing trend in the world due to their numerous advantages. The wind energy is free, inexhaustible and it produces no waste or greenhouse gases. Furthermore, it is a good method of supplying energy to remote areas. In this paper, a new variable-speed wind energy conversion systems (WECSs) with a squirrel cage induction generator (SCIG) and a new six-switch AC/AC converter as power electronic interface between SCIG and network is proposed. Characteristics of six-switch AC/AC converter are used for maximum power tracking control under different wind speed and delivering power to the grid, simultaneously. This configuration uses only six active switches and six diodes and has the lowest number of active switches among three-phase to three-phase AC/AC converters proposed hitherto in the literature. This converter offers sinusoidal input and output, unity power factor and more importantly, low manufacturing cost. Two simulations are performed for proposed configurations and results are presented. The results verify effectiveness of the proposed interface configuration.