Michal Gwozdz

Control system of power electronics current modulator utilized in diode rectifier with sinusoidal source current

In the article a structure of control circuit of power electronics current modulator, connected to DC circuits of diode rectifiers, is presented. This solution is very attractive in case of large power rectifiers due to obtaining close to sinusoidal power grid current and relatively low modulator power. The criterions of parameters selection of control circuit are described. Selected results of simulation researches are presented also.

Utilization of wideband power electronics current sources in Generator of Spatial Magnetic Field

The paper considers Generator of Spatial Magnetic Field for medicine purposes - magneto therapy. One of essential blocks there is a precision three-channel power electronics current source, powering set of space oriented induction coils (electromagnets) - sources of a magnetic field. The control module utilizes DSP based microcomputer for power electronics applications. The microcomputer is implemented at PCI card, which is integrated with industrial PC. The execution block of current source utilizes IGBT/IPM based power electronics inverter working in PWM mode. The paper describes fundamentals of current source control algorithms and selected test results of laboratory prototype of generator.

Wide-band power electronics current source for reference purposes

In the paper one of control methods of electrical systems is presented. In this particular case the electrical system has been precision wide-band power electronics current source. This source has been fundamental part of flexible Reference Current Generator for testing of energy meters and other laboratory purposes. The control module of Generator utilizes floating point DSP microcomputer for power electronics applications. This module controls directly H-bridge, IPM based, power electronics inverter with passive low-pass filter at the output. This type of controlled current source is able to generate current, that shape strictly responds the reference signal waveform. Following parts of the paper describes: structure, control algorithms and investigations results of laboratory model of Generator.

DSP Controlled Generator of Spatial Magnetic Field for Magnetotherapy

The paper considers generator of spatial magnetic field for medicine purposes. One of essential blocks there is precision three-channel power electronics current source, powering set of space oriented induction coils (electromagnets) being sources of magnetic field. The control module utilizes DSP based microcomputer for power electronics applications. This microcomputer is integrated with industrial PC as PCI card. The execution module consists of three H-bridge power electronics inverters, utilizing PVVM strategy. Individual sections of this paper describe fundamentals of current source control algorithms, electrical structure as well as test results of laboratory model of generator.

Utilization of Low Distortion Power Electronics Current Sources in Generator of Spatial Magnetic Field

The paper considers Generator of the Spatial Magnetic Field for medicine purposes. One of essential blocks there is three-channel power electronics current source, powering set of space oriented induction coils (electromagnets) ¿ sources of magnetic field. The control module utilizes DSP based microcomputer for power electronics applications. The microcomputer is integrated with industrial PC in form of PCI card. The execution block utilizes three power electronics inverters, utilizing PWM strategy. The paper describes fundamentals of current source control algorithms and test results of laboratory model of generator.

Power electronics active filter with controlled dynamics

Present tendencies of evaluation current distortion compensation methods aim to work out such compensator (serial or parallel active filter), which would be able to realize real time compensation. The assumed aim of parallel active filter work is dynamic compensation of differential current which is the difference between load current and reference current. Unfortunately dynamics of every real power electronics current source, being essential part of parallel filter, is limited. Responsible for this is finite inductance of coil at the output of inverter, being part of current source. Proposed idea of increasing dynamics of active filter depends on temporarily changing inductance of this coil. It can be done with using two windings coil, similar to transformer, which second winding is temporarily short-circuited, resulting in decreasing inductance of equivalent circuit of coil so dynamics of current source is higher.

Power electronics controlled voltage source based on modified sigma-delta modulator

The paper presents a conception of power electronics inverter based on a modified sigma-delta modulator (SDM) in the inverters control block. The proposed modulator includes the comparator with dynamic hysteresis instead of a latched comparator, being typically used in 1-bit SDMs. Thank to this feature a resolution of SDM output bit stream is, theoretically, unlimited. As result, value of THD of an inverter output voltage is essentially lower, compared to a typical SDM solution. This benefit is not paid by increase in the system complexity. Moreover, the control system is simpler than in a case of a conventional inverter. Due to very high frequency of a SDM output bit stream, in a power stage of inverter the gallium nitride (GaN) based E-HEMTs (E-HEMT: Enhancement mode High Speed Mobility Transistor) are implemented. However, in case of lower value of an inverter output power also Si based devices are still the right choice. In the paper the inverter control circuit basics, results of simulation experiments, and the design of voltage controlled voltage source (VCVS) for laboratory tests are presented.

Simulation and experimental models of 3-phase diode rectifier with power electronics current modulator

In this paper the structure of control system of power electronics current modulator is presented. This converter is placed in output circuit of 3-phase diode rectifier. With aid of such solution, power grid current of decribed rectifier is almost sinusoidal. Different structures of current regulator - part of control circuit - are considered. Chosen results of simulation and experimental researches are presented also.

Software Controller for Balancing of Current Distribution in Interleaved Converters

A parallelism is a well known technique for increasing the power rating of power electronics converters. Interleaved converters use a kind of parallelism that, thanks to their own particular features, makes it possible more accurately map the converters output current (or voltage) in a reference signal. However, interleaved converters present several disadvantageous. The most important problem consists in the fact that, converters output current may not be distributed equally in individual converters channels, what requires additional hardware support mechanism. In contrast to these methods, the cost effective, software only based solution of the controller for balancing of current distribution, is proposed in this work. The controller constitutes part of a control system of broad-band power electronics current source (VCCS) for ATE (Automated Test Equipment). This work presents basics of operation of the proposed controller as well as the investigation results of the simulation model of the VCCS.

Active power filter with sigma-delta modulator in control section

The work presents concept of 1-phase shunt Active Power Filter (APF) based on the modified sigma-delta modulator (SDM) in the control section. The modification depends on including in SDM the dynamic hysteresis comparator. Thank to this feature the resolution of SDM output bit stream is, theoretically, unlimited. As a result it is possible to more precise mapping of an APF input (power grid) current in a reference signal, compared to a PWM based inverter. Due to high switching frequency of power devices in an output stage of APF the GaN E-HEMTs are included. In the work basics of APF operation and results of its simulation model studies are presented.