Konrad Mauch

Control of parallel inverters in distributed AC power systems with consideration of line impedance effect

The authors have developed a new control technique which allows paralleled inverters to share linear or nonlinear load in a distributed AC power supply system. This technique does not require control interconnections and automatically compensates for inverter parameter variations and line impedance imbalances. Experimental results are provided in the paper to prove the concept.

Analysis of a ripple-free input-current boost converter with discontinuous conduction characteristics

Coupled inductor techniques supply a method to reduce the power converter size and weight and achieve ripple-free current. The boost power converter is a very popular topology in industry. However, the input-current ripple hinders efforts to meet electromagnetic interference (EMI) requirements. In particular, the input current becomes discontinuous and pulsating when the conventional boost power converter operates in the discontinuous inductor-current mode. This paper describes a boost power converter which has the same discontinuous properties as the conventional boost power converter. However, the proposed boost topology has continuous or ripple-free input current when it operates with discontinuous inductor-current. The proposed topology is compared with traditional converter topologies, such as the Sepic and Cuk power converters. Simulation results are presented. The prototype is built to demonstrate the theoretical prediction. The proposed boost topology is simple, with straightforward control ~the same as pulse-width modulation (PWM)\.

Modified boost converter with continuous inductor current mode and ripple free input current

The boost topology is very popular in industry. However, the input inductor current ripple affects its ability to meet EMI requirements. A ripple-free input inductor current boost topology operating in continuous inductor current mode is introduced in this paper. It is of simple topology and simple control strategy (the same as PWM). The proposed boost topology retains the advantages of the conventional boost topology, but with ripple-free input current. Simulation and experimental results are presented to verify the predicted theory.

Design of zero-current-switching fixed frequency boost and buck converters with coupled inductors

A boost power converter and a buck power converter are introduced in this paper. The input/output current can be made continuous with extra low ripple using a coupled inductor. Configurations and control strategy for this type of power converter are quite simple. This type of converter has been analyzed by using the MICROTRAN (EMTP) simulation package.<<ETX>>

A comparison of modified boost converters with continuous inductor current mode and ripple free input current with conventional converters

A low ripple or ripple free input current boost converter operating in continuous inductor current mode is very desirable in industry. In this paper, a new modified boost converter is proposed and analyzed. Compared to the conventional boost converter, the new boost converter can achieve ripple free input current by using coupled inductor techniques. Compared to the Cuk and Sepic converters, the new boost converter has several advantages which may result in a high efficiency. The small signal model of the new boost converter is analyzed. A comparison between this circuit and several alternatives is presented. The predicted theory is verified experimentally.

Some novel four-quadrant DC-DC converters

Several four-quadrant converter topologies are introduced in this paper. From the voltage gain point of view, it is found that the proposed four-quadrant converter topologies are combination of the buck, boost and buck-boost type converters. One of the four proposed topologies is analyzed and discussed as an example in this paper. Some proposed topologies with only one active switch and one diode can be operated in two quadrants. They can also have four quadrant operation if two active switches and their anti-parallel diodes are used. The proposed topologies are compared with the basic DC-DC converter topologies and several interesting conclusions are made. Some simulation results are presented.

Synthesis of two-inductor DC-DC converters

A synthesis principle for two-inductor DC-DC converters with ripple free input/output current is summarized by the study of existing ripple free converter topologies. The LCL structure is found to be very important for ripple free converters. Several variations of LCL cells are derived. It is found that all existing ripple free converters are derivations of the LCL converter cells. In addition, several modified topologies with ripple free input/output current are developed and two modified converter topologies with only two active switches can operate in four-quadrant. Two-quadrant operation may also be achieved by using one active switch and one passive switch.

A comparison between some proposed boost topologies and conventional topologies in discontinuous inductor current mode

A new modified boost power converter topology with an LC branch in parallel with the diode is introduced. The new boost topology has continuous and ripple-free input current. Its properties are discussed and found to be the same as the conventional boost topology operating in the discontinuous inductor current mode. It is also compared to another modified boost power converter which can achieve continuous and ripple free input current. Compared to the traditional power converters, several advantages are identified. The predicted theory is verified experimentally.

Analysis of a modified buck converter

A modified buck converter is studied in this paper. Its steady state characteristics, small signal models when it operates in either continuous conduction mode or discontinuous conduction mode are discussed. Coupled inductor techniques can be applied to this topology. It is also found that the modified converter has faster dynamic response than the conventional buck converter. In particular, this topology can overcome the high inrush current.

A simple spreadsheet-based converter performance model reduces analysis and design time

A fast, simple predictive modeling method to evaluate a switching power converter performance is introduced, based on the converters RMS current and components parameters. This method can be used in any personal computer spreadsheet such as EXCEL/sup (C)/. By using this modeling method, converter efficiency can be predicted. The converters efficiency can also be improved under the instruction of the proposed modeling method.