Robust Deadbeat Current Control Method for Three-Phase Voltage-Source Active Power Filter

Nishida, Katsumi,Ahmed, Tarek,Nakaoka, Mutsuo The Korean Institute of Power Electronics 2004 JOURNAL OF POWER ELECTRONICS Vol.4 No.2

This paper is concerned with a deadbeat current control implementation of shunt-type three-phase active power filter (APF). Although the one-dimensional deadbeat control method can attain time-optimal response of APF compensating current, one sampling period is actually required fur its settling time. This delay is a serious drawback for this control technique. To cancel such a delay and one more delay caused by DSP execution time, the desired APF compensating current has to be predicted two sampling periods ahead. Therefore an adaptive predictor is adopted for the purpose of both predicting the control error of two sampling periods ahead and bringing the robustness to the deadbeat current control system. By adding the adaptive predictor output as an adjustment term to the reference value of half a source voltage period before, settling time is made short in a transient state. On the other hand, in a steady state, THD (total harmonic distortion) of the utility grid side AC source current can be reduced as much as possible, compared to the case that ideal identification of controlled system could be made.

Robust Deadbeat Current Control Method for Three-Phase Voltage-source Active Power Filter

Katsumi Nishida,Tarck Ahmed,Mutsuo Nakaoka 전력전자학회 2004 JOURNAL OF POWER ELECTRONICS Vol.4 No.2

This paper is concerned with a deadbeat current control implementation of shunt-type three-phase active power filter (APF) Although the one-dimensional deadbeat control method can attain time-optimal response of APF compensating current, one sampling period is actually required for its settling time This delay is a serious drawback for this control technique To cancel such a delay and one more delay caused by DSP execution time, the desired APF compensating current has to be predicted two sampling periods ahead Therefore an adaptive predictor is adopted for the purpose of both predicting the contiol error of two sampling periods ahead and bringing the robustness to the deadbeat current control system. By adding the adaptive predictor output as an adjustment term to the reference value of half a source voltage period before, settling time is made short in a transient state. On the other hand, in a steady state, THD (total harmonic distortion) of the utility grid side AC source current can be reduced as much as possible, compared to the case that Ideal identification of controlled system could be made

Advanced Control of a PWM Converter with a Variable-Speed Induction Generator

Ahmedt, Tarek,Nishida, Katsumi,Nakaoka, Mutsuo,Tanaka, Toshihiko The Korean Institute of Power Electronics 2007 JOURNAL OF POWER ELECTRONICS Vol.7 No.2

This paper describes simple control structures for a vector controlled stand-alone induction generator (IG) for use under variable speeds. Different control principles, indirect vector control and deadbeat current control, are developed for a voltage source PWM converter and the three-phase variable speed squirrel-cage IG to regulate DC-link and generator voltages with a newly designed phase locked loop circuit. The required reactive power for the variable speed IG is supplied by means of a PWM converter and a capacitor bank to buildup the voltage of the IG without the need for a battery, to reduce the rating of the PWM converter while using only three sensors and to eliminate the harmonics generated by the PWM converter. These proposed schemes can be used efficiently for variable speed wind energy conversion systems. The measurements of the IG systems at various speeds and loads are given and show that these systems are capable of good AC and DC voltage regulation.

A Novel Variable-Speed Renewable-Energy Generation System of Induction Generator and PWM Converter for Small-Scale Hybrid Power Applications

Tarek Ahmed,Katsumi Nishida,Hyun-Woo Lee,Mutsuo Nakaoka 대한전기학회 2005 대한전기학회 학술대회 논문집 Vol.2005 No.7

Induction Generator Using PWM Converter and Its Small - Scale Power Applications to Variable - Speed Renewable - Energy Generation

Tarek Ahmed,Katsumi Nishida,Mutsuo Nakaoka 전력전자학회 2005 JOURNAL OF POWER ELECTRONICS Vol.5 No.4

This paper describes a simple control structure and power conditioning system for an indirect vector controlled stand-alone induction generator (IG) used to operate under variable speed. The required reactive power for the IG system is supplied by means of a capacitor bank and a voltage-source PWM converter. Using a capacitor bank to transfer the reactive power to the IG under the rated speed and no-load conditions starts the IG operation and reduces the PWM converter size. The vector control structure for the variable speed IG power conditioning system compensates for changes in the electrical three-phase and DC loads while considering the magnetizing curve of the IG. The vector control structure is developed to regulate the DC link voltage of the PWM converter and the IG output voltage. The experimental and simulated performance results of the IG power conditioning system at various speeds and loads are given and show that this proposed scheme can be used efficiently for a variable speed, wind energy conversion system.

Advanced Control of a PWM Converter with a Variable-Speed Induction Generator

Tarek Ahmed,Katsumi Nishida,Mutsuo Nakaoka,Toshihiko Tanaka 전력전자학회 2007 JOURNAL OF POWER ELECTRONICS Vol.7 No.2

This paper describes simple control structures for a vector controlled stand-alone induction generator (IG) for use under variable speeds. Different control principles, indirect vector control and deadbeat current control, are developed for a voltage source PWM converter and the three-phase variable speed squirrel-cage IG to regulate DC-link and generator voltages with a newly designed phase locked loop circuit. The required reactive power for the variable speed IG is supplied by means of a PWM converter and a capacitor bank to buildup the voltage of the IG without the need for a battery, to reduce the rating of the PWM converter while using only three sensors and to eliminate the harmonics generated by the PWM converter. These proposed schemes can be used efficiently for variable speed wind energy conversion systems. The measurements of the IG systems at various speeds and loads are given and show that these systems are capable of good AC and DC voltage regulation.

Wind Power Grid Integration of an IPMSG using a Diode Rectifier and a Simple MPPT Control for Grid-Side Inverters

Tarek Ahmed,Katsumi Nishida,Mutsuo Nakaoka 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.5

In this paper, a 1.5 kW Interior Permanent Magnet Synchronous Generator (IPMSG) with a power conditioner for the grid integration of a variable-speed wind turbine is developed. The power-conditioning system consists of a series-type 12-pulse diode rectifier powered by a phase shifting transformer and then cascaded to a PWM voltage source inverter. The PWM inverter is utilized to supply sinusoidal currents to the utility line by controlling the active and reactive current components in the q-d rotating reference frame. While the q-axis active current of the PWM inverter is regulated to follow an optimized active current reference so as to track the maximum power of the wind turbine. The d-axis reactive current can be adjusted to control the reactive power and voltage. In order to track the maximum power of the wind turbine, the optimal active current reference is determined by using a simple MPPT algorithm which requires only three sensors. Moreover, the phase angle of the utility voltage is detected using a simple electronic circuit consisting of both a zero-crossing voltage detecting circuit and a counter circuit employed with a crystal oscillator. At the generator terminals, a passive filter is designed not only to decrease the harmonic voltages and currents observed at the terminals of the IPMSG but also to improve the generator efficiency. The laboratory results indicate that the losses in the IPMSG can be effectively reduced by setting a passive filter at the generator terminals.

Static VAR Compensator-based Feedback Control Implementation for Self-Excited Induction Generator Terminal Voltage Regulation Driven by Variable-Speed Prime Mover

Tarek Ahmed,Katsumi Nishida,Mutsuo Nakaoka 전력전자학회 2004 JOURNAL OF POWER ELECTRONICS Vol.4 No.2

In this paper, the steady-state analysis of the three-phase self-excited induction generator (SEIG) driven by a variable-speed prime mover (VSPM) such as a wind turbine is presented. The steady-state torque-speed characteristics of the VSPM are considered With the three-phase SEIG equivalent circuit for evaluating the operating performances due to the inductive load variations Furthermore, a PI closed-loop feedback voltage regulation scheme based on the static VAR compensator (SVC) for the three-phase SEIG driven by the VSPM is designed and considered for the wind power generation conditioner The simulation and experimental results prove the practical effectiveness of the additional SVC with the PI controller-based feedback loop in terms of fast response and high performances

A Self-Excited Induction Generator with Simple Voltage Regulation Suitable for Wind Energy

Tarek Ahmed,Katsumi Nishida,Mutsuo Nakaoka 전력전자학회 2004 JOURNAL OF POWER ELECTRONICS Vol.4 No.4

In this paper, a three-phase induction machine-based wind power generation scheme is proposed. This scheme uses a low-cost diode bridge rectifier circuit connected to an induction machine via an ac load voltage regulator (AC-LVR) to regulate dc power transfer. The AC-LVR is used to regulate the DC load voltage of the diode bridge rectifier circuit which is connected to the three-phase self-excited induction generator (SEIG). The excitation of the three-phase SElG is supplied by the static VAR compensator (SVC). This simple method for obtaining a full variable-speed wind turbine system by applying a back-to-back power converter to a wound rotor induction generator is useful for wind power generation at widely varying speeds. The dynamic performance responses and the experimental results of connecting a 5kW 220V three-phase SEIG directly to a diode bridge rectifier are presented for various loads. Moreover, the steady-state simulated and experimental results of the PI closed-loop feedback voltage regulation scheme prove the practical effectiveness of these simple methods for use with a wind turbine system.<br/>

Wind Power Grid Integration of an IPMSG using a Diode Rectifier and a Simple MPPT Control for Grid-Side Inverters

Ahmed, Tarek,Nishida, Katsumi,Nakaoka, Mutsuo The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.5

In this paper, a 1.5 kW Interior Permanent Magnet Synchronous Generator (IPMSG) with a power conditioner for the grid integration of a variable-speed wind turbine is developed. The power-conditioning system consists of a series-type 12-pulse diode rectifier powered by a phase shifting transformer and then cascaded to a PWM voltage source inverter. The PWM inverter is utilized to supply sinusoidal currents to the utility line by controlling the active and reactive current components in the q-d rotating reference frame. While the q-axis active current of the PWM inverter is regulated to follow an optimized active current reference so as to track the maximum power of the wind turbine. The d-axis reactive current can be adjusted to control the reactive power and voltage. In order to track the maximum power of the wind turbine, the optimal active current reference is determined by using a simple MPPT algorithm which requires only three sensors. Moreover, the phase angle of the utility voltage is detected using a simple electronic circuit consisting of both a zero-crossing voltage detecting circuit and a counter circuit employed with a crystal oscillator. At the generator terminals, a passive filter is designed not only to decrease the harmonic voltages and currents observed at the terminals of the IPMSG but also to improve the generator efficiency. The laboratory results indicate that the losses in the IPMSG can be effectively reduced by setting a passive filter at the generator terminals.