Martin Novak

Usability of GeoWeb sites: case study of Czech regional authorities web sites

Today, many of the solved problems are spatially oriented. It means that more and more people need to use spatial information. They need to be able to use it quickly, without any special software tool and without any special training. So they need an easy-to-use solution. GeoWeb sites can perfectly fit the demands but they must be properly designed. The article describes usability testing of GeoWeb sites of all Czech regional authorities and proposes some recommendations how user interface should be designed. Recommendations can be generalized because there are no significant differences between private and public sector. The main differences are between target groups of the users: regular or casual users.

Digital controlled high speed synchronous motor

Contribution deals with predictive torque control of the high speed permanent magnet synchronous motor. Such motors are used for electrically driven compressors (E-booster) on turbocharged gasoline or diesel engines. Theory and experimental results from the laboratory are revealed.

Electrically-driven compressors on turbocharged engines with high-speed synchronous motors

Paper deals with torque control of high-speed permanent-magnet synchronous motor for driving compressor of supercharged combustion engines. Control structure, which includes regimes with both full magnetic flux and flux-weakening, is described. Paper presents the research working place and test results achieved at 40 krpm permanent-magnet synchronous motor.

Heuristic evaluation of usability of GeoWeb sites

Usability of software belongs today to the top priorities of both managers and users of information technologies because the dependency of the majority of mankind activities on information and communication technologies in general is increasing rapidly. This requirement concerns geographic information systems in general but it principally concerns GeoWeb sites because spatial data and tools for their utilization are nowadays in great demand by end-users. GeoWeb sites can provide them an easy-to-use solution but they must be properly designed. The article describes proposal of heuristic evaluation of usability of GeoWeb sites and a case study: the proposed heuristic evaluation is applied to GeoWeb sites of all Czech regional authorities. ISO/IEC 9126 quality model is used as a framework and heuristic evaluation in according to Nielsen is used as a method for usability inspection. In the end some recommendations how user interface should be designed are proposed.

High speed synchronous motor control for electrically driven compressors on overcharged gasoline or diesel engines

This paper deals with torque control of high speed permanent magnet synchronous motor for driving a compressor of supercharged combustion engine. Control structure which includes regimes with both full magnetic flux and flux weakening is described. Paper describes the research working place and presents test results achieved on 40 000 rev/min synchronous permanent magnet motor.

Application of Sinusoidal Phase Current Control for Synchronous Drives

This paper presents the experience gained in the field of synchronous motor phase current control. Properties of linear and nonlinear control are compared. The influence of induced voltage is mentioned and test results from two test stands are presented

Implementation of SiC inverter for high frequency, medium voltage applications

This paper describes the experiments with a custom build high frequency SiC inverter. The inverter uses the CCS050M12CM2 module with SiC MOSFET (1200V, 50A). A comparison of SiC MOSFET and Si IGBT modules both from datasheets and different scientific papers showed that SiC MOSFETs have higher efficiency, smaller losses and are capable to work with higher frequency than Si IGBTs. The characteristics of SiC MOSFET and Si IGBT inverter were measured in our laboratory and showed that SiC MOSFET had smaller power static losses and switching losses than Si IGBT, SiC MOSFET had higher efficiency and can operate under higher switching frequency than Si IGBT. The switching characteristics of SiC module have been measured up to a frequency of 30 kHz. The problem of gate-source voltage overshoot is considered here; it is caused by parasitic capacitances and inductances. The correct value of damping resistor is tuned to suppress overshoot.

Methods of deploying security standards in a business environment

Information is the essential building block of society and is found in each field of business. They can represent a business plan, personnel data, manufacturing know-how, financial transactions and many others. Information is part of company assets and thus has to be protected. This article describes methods of deploying security standards in a business environment. The practical part of the article describes implementation of Information Security Management System in a real automotive company located in the Czech Republic.

An SiC inverter for high speed permanent magnet synchronous machines

This paper present experimental results obtained during the construction of an SiC based inverter for high speed permanent magnet synchronous machines (PMSM). First a comparison between an IGBT and SiC modules used for the same application is presented. The modules static and switching losses are experimentally obtained and compared. The SiC module show significantly lower switching losses. Then the SiC inverter design is described and experimental results are shown. It is found that parasitic inductances in both the gate driver and DC intermediate circuit play a major role and need to be minimized. One procedure using vertically aligned PCB traces is described and measured results are presented. The presented SiC based inverter was successfully tested with the high speed PMSM up to the application full voltage 600V. It was also tested with a high switching frequency up to 500kHz although the target frequency is only 100kHz.

Experimental micro-turbine power generator

This paper presents a design of an experimental micro-turbine power generator for combined electrical energy and heat production. The generator is composed of an automotive turbocharger and a high speed permanent magnet synchronous motor. The generator parameters are 40 000 RPM, torque 7 Nm. The control system is presented as well as the control algorithm. Some test results obtained during initial workbench testing with unloaded motor are shown.