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Control system of APF device
Kokeš, Petr
Control method of Active Parallel Filter (APF), which is based on the previously developed AFE control method utilizing the LQR controller, is described. The APF device is able to compensate fully reactive load current and reduce considerably higher harmonics up to 11th order. APF functionality was tested on a physical model of the LV 4-level converter with flying capacitors in steady and transient states for both symmetrical and asymmetrical loads. The control system was implemented into Emadyn-F controller.
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High Power PWM rectifiers
Valouch, Viktor ; Šimek, Petr ; Škramlík, Jiří
High power, high voltage PWM rectifiers with low swirching frequency are analyzed in terms of attainable powers exchangedwith the grid and of their current frequency spectra. Four-level PWM rectifiers with rated powers S = 2, 4, 8 MVA and the switching frequency 800 Hz per one switching element are considered, thus the controlller sampling frequency 1600 Hz is used. Selected results of simulation as wellas experimental tests are presented.
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Software Phase Lock Loops of PWM Rectifiers
Šimek, Petr ; Škramlík, Jiří ; Valouch, Viktor
In the paper the properties of three PLL techniques (known under names DSC-, DDSRF- a FVAVG-PLL) for different states of the feeding three-phase voltage system are assessed. As a crucial quality criterion of synchronization to the positive component of the fundamental harmonic voltage the errorbetween an estimated and real angle of the positive component of the fundamental harmonic voltage vector was selected. Two sampling periods Ts=0.05 ms and 0.5 ms as well as two gain values of a PL-type compensator were treated.
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Porovnání usměrňovače s šířkově pulzní modulací s usměrňovačem fázově řízeným
Lettl, Jiří
The presented paper deals with measured waveforms of realized PWM rectifier with practically sinusoidal input current and controllable phase shift between input current first harmonic and supply voltage first harmonic. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.
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