C. Hernandez

A comparison between the buck, boost and buck-boost inverters

In this paper, an analysis and experimental study of three kinds of inverters are presented. Beginning with the traditional full-bridge buck inverter; followed by two different inverter approaches, the boost and buck boost ones. These last two converters have the property of producing an output voltage higher or lower than the input voltage additionally to its inversion capability, which is a desired characteristic in some applications. The paper include a comparison between the different inverter approaches, additional to the analysis and experimental results of the converters. The control strategy used for all the converters is the sliding mode control in order to introduce a good dynamic response for the closed loop system.

A fast ac voltage regulator

The study and implementation of an AC voltage regulator is presented in this paper. Traditionally an AC voltage regulator is made with a transformer tap changer or with an AC-AC converter based on buck topologies, recently the developments in ac-ac converter makes feasible the implementation of voltage regulator with other topologies. In this paper is analyzed an ac voltage regulator based on the ac-ac buck-boost converter. Simulation and experimental results are presented.

A different AC voltage regulator based on tapped transformer

An AC voltage regulator based on a tapped transformer is presented in this paper, but do not considers SCRs as switching devices, the system offers a fast response under input voltage variations. An AC voltage regulator can be made with a transformer tap changer or with an AC-AC converter based on buck or buck-boost topologies. The first one is simple but with slow response traditionally and the others are the opposite. In this paper is analyzed an AC voltage regulator based on a tapped transformer; however a fast response is obtained. Experimental results are presented.

A current limiter based on an active current power filter

Different loads demand a high current at the start-up; an example are equipments that are composed by motors, also there are some type of loads that demands large currents in short periods of time like the arc welding systems. These types of loads introduce disturbances at the input voltages, causing voltage sags or flickers. In this paper is presented a current active power filter operated as a start-up current limiter, which permits to avoid the disturbances introduced by these types of loads. The operation, simulation and experimental results are presented.

Electronic ballast based on a series active input current shaper

Great part of the energy generated in the industrialized world is consumed by lighting, and to reduce the energy consumption fluorescent lamp are used; to operate a fluorescent lamp properly an electronic ballast is required. Different techniques to improve the characteristics of the topologies of electronic ballast are reported in literature; to fill the standard specifications at low cost, one option is to use the active input current technique. In this paper an electronic ballast based on a series active input current shaper is discussed. Design and experimental results are presented.

Capacitor balancing method for neutral point clamped three-level inverter

DC/AC converters are widely used in several applications; recently the multilevel configuration for the DC/AC conversion is being studied. In this type of converters a traditional concern is the capacitor voltage unbalance problem. In this paper a method to maintain regulated the capacitor voltage of a neutral point clamped three-level inverter is presented. The operation, implementation and simulation results are shown.

A six-switch three-level current source inverter

In several applications DC/AC converters are widely used; traditionally they can be classified in voltage source inverters (VSI) and current source inverters (CSI). Their use depends on the application. Other possibility for the DC/AC conversion is the multilevel configuration, and the most analyzed is the VSI. In this paper a multilevel current source inverter (MCSI) is proposed. The operation, analysis and implementation are presented; also simulation and experimental results are shown.

A new active input current shaper with reduced power processing

In this paper a new active input current shaper (AICS) with reduced power processing is presented. The traditional active input current shaper recycles an amount of power to demand an input current with low harmonic content; this recycled energy reduces the efficiency. In this paper is analyzed a new CA/CD converter, in which some of the energy delivered to the load is not processed and also an amount of energy is recycled to shape the input current: that is a AICS with reduced power processing, so a good efficiency is obtained.

Input current shaper operating in DCM

Several AC/DC converters have been presented in order to meet the power quality regulations maintaining the lowest number of components with the purpose of minimize the cost and complexity. In this paper the parallel active input current shaper (PAICS) operated in discontinuous conduction mode (DCM) is presented. In difference with the traditional series AICS, the proposed scheme connects the auxiliary output of the main converter in parallel of the rectified ac mains, and also the design is made to correct the power factor not only to fulfill the standard specifications. Operation, design and experimental results are presented.

Two inputs DC/DC Converter applicable in clean-energy resources

A two inputs DC/DC Converter is proposed in this paper, the converter is applicable to clean-energy resources such as solar arrays, wind generators, fuel cells, and so forth. The power can be demanded to both input voltage sources simultaneously or to each one independently. The operation of the converter is presented in detail. Simulation and experimental results are presented.