Krzysztof Sozański

Sliding DFT control algorithm for three-phase active power filter

This paper describes the sliding discrete Fourier transform (DFT) algorithm as an alternative for typical DFT used for spectrum analysis and synthesis. As an example a control circuit for a three-phase 75 kVA parallel active power filter (APF) is used. Such filters have been built and tested. Some illustrative, experimental results are also presented in the paper. The control algorithms of the proposed APF are implemented in the fixed-point digital signal processor TMS320F2812 from Texas Instruments using eZDSP system kit. The presented control APF algorithm is a good alternative to classical APF control algorithms, because it allows easy selection of control parameters in mains currents: imbalance, reactive power or harmonics contents. In the proposed circuit transient performance of APF is improved using noncausal predictive current compensation.

Digital control circuit for class-D audio power amplifier

This paper describes a digital speaker system with a hybrid PWM digital modulator for a class-D power audio amplifier using the oversampling and noise-shaping techniques. Results of measurements of the output signal spectrum for the audio frequency band with a sinusoidal input signal are shown. The presented speaker system achieves a signal-to-noise ratio (SNR) near to 75 dB in the audio band (20 Hz to 20 kHz).

Digital control circuit for active power filter with modified instantaneous reactive power control algorithm

This paper describes the proposed active power filter with the control circuit based on the modified instantaneous reactive power control algorithm. The control circuit was realized using digital signal processor ADSP-21065. In the proposed circuit an advanced current controller algorithm realized using the digital signal processor ADSP-21065 is employed. The active power filter circuit was build and tested. Some illustrative, experimental results are also presented in the paper.

Digital Signal Processing in Power Electronics Control Circuits

Introduction.- Analog Signals Conditioning and Discretization.- Selected Methods of Signal Filtration and Separation and their Implementation.- Selected Active Power Filter Control Algorithms.- Digital Signal Processing Circuits for Digital Class D Power Amplifiers.- Conclusion.

Shunt active power filter with improved dynamic performance

This paper describes a shunt active power filter (APF) with improved dynamic performance. When the value of load current changes rapidly, the typical APF transient response is too slow, and the line current suffers from dynamic distortion. This distortion causes an increase in harmonic content in the line current, which is dependent on a time constant. The APF control current dynamics is dependent on the inverter output time constant consisting of APF output inductance and resultant impedance of load and mains. In the proposed circuit transient performance of APF is improved using a modified output inverter. According to this modification the APF dynamics are improved. The Matlab simulation results of a modified APF are also presented in the paper.

The Shunt Active Power Filter with Better Dynamic Performance

This paper describes the proposed active power filter (APF) with a modified output inverter. When the value of load current changes rapidly, the APF transient response is too slow the line current suffers from dynamic distortion. This distortion causes an increase of harmonic content in the line current, which is dependent on a time constant. The APF control current dynamics is dependent on the inverter output time constant consisting of APF output inductance and resultant impedance of load and mains. According to this modification the APF dynamics are improved. The Matlab simulation results of the modified APF are also presented in the paper.

Noncausal current predictor for active power filter

This paper describes the proposed active power filter (APF) with a new control circuit based on an control algorithm using a non-causal current predictor. The control circuit design incorporates the digital signal processor ADSP-21065L and FPGA circuit. In the proposed circuit transient performance of APF is improved. The active power filter circuit has been built and tested, and some illustrative, experimental, results are also presented in the paper.

A filter bank solution for active power filter control algorithms

This paper describes the proposed active power filter (APF) with a new control circuit based on an algorithm using a filter bank and a harmonic predictor. The control circuit was realized using the digital signal processor ADSP-21065L and FPGA circuit. In the proposed circuit transient performance of APF is improved. The active power filter circuit has been built and tested, and some illustrative, experimental results are also presented in the paper.

Realization of a Digital Control Algorithm

Chapter four covers problems concerning the realization of digital control algorithms. The following realizations of digital control circuit are considered: digital signal processors, microprocessors, microcontrollers, and programmable digital circuits. All these solutions are compared. The general problems of analog signal acquisition for digital control circuit, such as sampling rate, number of bits, signal to noise ratio (SNR), anti-aliasing filter, bandwidth of signal, signal range are discussed too. Digital filter and filter bank are also considered, with special emphasis filters which are useful for active power filter (APF) control circuit, sliding discrete Fourier transform (DFT). Special attention is paid to improve APF dynamic range and using a non-causal solution it is possible to dump output stage dynamic distortion. For unpredictable loads a three-phase multirate APF with modified output inverter was designed. Finally, experimental test result of considered APF is presented and discussed.

Improved shunt active power filters

This paper describes a shunt active power filters (APF) with improved dynamic performance. When the value of load current changes rapidly, the APF transient response is too slow, the line current suffers from dynamic distortion. This distortion causes an increase of harmonic content in the line current, which is dependent on a time constant. The APF control current dynamics is dependent on the inverter output time constant consisting of APF output inductance and resultant impedance of load and mains. In the proposed circuit transient performance of APF is improved using non-causal predictive current compensation. In the second solution modified output inverter is used. According to this modification the APF dynamics are improved. The Matlab simulation results of the modified APF are also presented in the paper. As an example a control circuit for a three-phase 75 kVA parallel active power filter (APF) is used.