Marek Pastor

Soft-Switching Full-Bridge PWM DC–DC Converter With Controlled Output Rectifier and Secondary Energy Recovery Turn-Off Snubber

A zero-voltage and zero-current switching full-bridge pulse-width modulated dc-dc converter with controlled secondary-side rectifier using a novel nondissipative energy recovery turn-off snubber is presented in this paper. Using a controlled rectifier, a turn-off snubber, and an innovative control algorithm, the circulating current of the converter is eliminated and soft switching for all power switches of the inverter is achieved for full-load range from no-load to short circuit. The principle of converter operation is explained and analyzed and the experimental results on a 4.5 kW, 100 kHz laboratory model of the converter are presented.

Zero-Voltage and Zero-Current Switching PWM DC–DC Converter Using Controlled Secondary Rectifier With One Active Switch and Nondissipative Turn-Off Snubber

Soft switching pulse-width modulation (PWM) dc–dc full-bridge converter with controlled rectifier on the secondary side of the high-frequency power transformer is presented in this paper. An active secondary switch, including new nondissipative passive energy recovery turn-off snubber on the secondary side and modified PWM control algorithm, provide conditions for zero-voltage and zero-current turn-on and zero-current turn-off of IGBT transistors on the primary side of the high-frequency dc–dc converter. The simple passive energy recovery snubber ensures also zero-voltage turn-off of the transistor on the secondary side of the power transformer. The principle of operation is explained and analyzed and consequently verified on a 2 kW, 50 kHz laboratory model of the converter.

Synchronous PWM control of triple transformer-connected inverters for photovoltaic system

This paper presents results of research of modulation processes in power conversion system with triple voltage source inverters, supplied by photovoltaic (PV) strings, and connected to a four-winding transformer. The transformer has in this case specific connections between the secondary windings and inverters, allowing providing of multilevel voltages at secondary windings of the transformer. Specialized space-vector-based strategy of pulsewidth modulation (PWM) has been used for control of inverters, insuring quarter-wave symmetry of winding voltages for any modulation indices and switching frequency of inverters. Analysis and comparison of harmonic composition of winding voltages and output voltages of inverters has been done. The validity of the analyzed processes has been verified by simulations: three basic variants of the scheme of modulation have been applied for control of inverters.

Multiphase quad-inverter system with feedforward synchronous PWM and nonlinear voltage regulation

This manuscript presents modified scheme of synchronous space-vector modulation allowing providing nonlinear dependences between the fundamental voltage and fundamental frequency of dual three-phase open-winding ac drive with four modulated inverters. Behavior of the system with six control modes (characterized by different dc-voltages and switching frequencies of inverters) and two nonlinear Voltage/Frequency ratios has been analyzed and simulated by the means of MATLAB-software.

REGULATION OF DYNAMIXEL ACTUATORS IN ROBOT MANIPULATOR MOVEMENT

The article deals with the possibilities of movement control of a five-joint robot manipulator, which is composed of Dynamixel actuators. It contains a description of sending user-defined data, which are stored in individual addresses of the actuators’ control unit. According to these data, the actuator is able to change the parameters of movement, such as velocity, dynamics of acceleration and deceleration, accuracy of reaching a specific position, etc. The article also compares the settings of individual parameters.

High-Frequency Soft-Switching PWM DC-DC Converter with Active Output Rectifier Operating as a Current Source for Arc Welding Applications

Abstract This paper introduces a high-frequency soft-switching pulse-width modulation DC-DC power converter with secondary active rectifier tested as a DC current source for arc welding applications. The soft-switching DC-DC converter consists of a high-frequency full-bridge inverter, high-frequency power transformer, and a controlled output rectifier with new secondary energy recovery turn-off snubber. Circulating currents in the converter are reduced by using active rectifier, and RMS values of the currents in primary and secondary switches are decreased by utilizing a novel control algorithm. The experimental results of a 4.5 kW DC-DC converter working at switching frequency of 100 kHz are presented.

Novel soft switching DC/DC converter with active rectifier and improved active snubber topology for full load range application

A paper is dedicated to a special isolated DC/DC converter with active rectifier which in cooperation with an improved active snubber ensures the soft switching of all transistor switches in full load range. Gradually in the paper, at first analysis of proposed isolated DC/DC converter with active rectifier topology is done, and then the proposed active snubber topology is analyzed. At the end, a comprehensive verification of proposed complete topology operation is done by presentation of results of converter model measurements.

High-Frequency soft-switching DC-DC converter with full-bridge output rectifier

The paper describes design, simulation and laboratory measurement results of the high-frequency softswitching DC-DC converter with half-controlled output fullbridge rectifier.

Comparative analysis of modulation techniques in frequency converter

A generalized frequency converter has been realized which makes use of a cyclo-converter in newer form AC-AC converter. An attempt has been made to operate this converter both in a conventional low frequency AC-AC converter and a new high frequency AC-AC converter. The ability to directly affect the frequency conversion of power without any intermediate stage involving DC power is a huge advantage of the system. The output of this converter has a frequency either fo = fi × Nr or fo = fi/Nr. where Nr is an integer and fi is the source frequency. A methodology is developed to generate the required trigger signal for any integer multiple/sub multiple of the output frequency. The undesirable harmonic components in the output of the frequency converter have been minimized using four modulation techniques namely; sinusoidal pulse width modulation (SPWM), delta modulation (DM), trapezoidal modulation (TM) and space vector modulation (SVM) technique. The converter is simulated using well known software package MATLAB. Comparative simulation analysis is presented for a single phase frequency converter (SPFC) topology with all these modulation techniques when the converter is operating both step up as well as for step down mode.

Stability of Grid-Connected Inverter with LCL Filter

The paper analyses oscillations in a singlephase grid connected inverter with the LCL output filter. Passive and active damping techniques are designed and compared by simulations. The inverter is controlled by a proportional resonant controller.