Celso B. Tischer

Hybrid method for control of voltage regulation applied in micro hydro power station

This paper deals with the development of a hybrid method of control for voltage regulation in micro hydro power station using self-excited induction generation. The proposed method performs the voltage regulation with the use of capacitor banks plus static VAR compensator. A considerable literature review was undertaken to identify the key control systems for voltage regulation applied to self-excited induction generator. A control algorithm and a project for the variable capacitors are proposed based on the resolution of normative procedures of Electricity Distribution in the National Electric System. Simulation and experimental results are presented to demonstrate the performance of the proposed hybrid method for the voltage regulation of the self-excited induction generator during variations of different types of load. Moreover, experimental results concerning the analysis of reactive power processed by the static VAR compensator during its operation in the hybrid method are obtained. These results are compared with the results obtained through the method that uses only the static VAR compensator, where the hybrid method has advantages in terms of reduction of the size of the static VAR compensator.

Supervisory and control system development applied to distributed generation using Web tools

This paper proposes a system of control and data acquisition (SCADA) to be applied in a distributed generation system. This system was developed with low-cost technology and it is based in wireless communication to perform the exchange of information between generation system and SCADA. The implementation of the proposed system contributes to operation, monitoring and maintenance of systems named smart grids, allowing the management of different generation sources, such as hydro, solar, wind, and others, through conventional monitoring systems like mobile devices, employing Web tools. Experimental results are presented in order to demonstrate the applicability of the system developed.

Hybrid topology and PRD controller applied in three-phase system based on induction generator

This paper deals with a control system for voltage regulation in stand-alone generation systems based on self-excited induction generators (SEIG). It is considered a three-wire hybrid topology composed by switchable capacitor banks and distribution static compensator (DSTATCOM). While the switchable capacitor banks supply the most part of the reactive power for voltage regulation, the DSTATCOM is controlled in order to supply the difference of reactive power, balance induction generation (IG) currents and compensate harmonics of load currents. To accomplish that, it is proposed the use of proportional-resonant-derivative (PRD) controllers in association to proportional-integral (PI) controllers to control the compensation currents processed by DSTATCOM. The proposed method of voltage regulation using DSTATCOM-switchable capacitors is implemented on an IG prototype system and the test results are presented to demonstrate its performance.

Voltage regulation of stand-alone micro-generation SEIG based system under nonlinear and unbalanced load

This study deals with a control system for voltage regulation of stand-alone generation systems based on self-excited induction generators (SEIG). It is considered a four-wire hybrid topology composed by switchable capacitor banks and distribution static compensator (DSTATCOM). While the switchable capacitor banks supply the most part of the reactive power for voltage regulation, the DSTATCOM is controlled in order to supply the difference of reactive power, to balance IG currents and compensate harmonics of load currents. To accomplish that, it is proposed the use of proportional-resonant-derivative (PRD) controllers in association to proportional-integral (PI) controllers to control the compensation currents processed by DSTATCOM. The proposed method of voltage regulation using DSTATCOM-switchable capacitors is simulated in software Simulink/Matlab® and the results are presented to demonstrate its performance.

Synchronization method and frequency tracking applied on voltage converters

This paper proposes a new closed-loop synchronization method for single-phase voltage converters. It presents a good performance under highly distorted grid voltages. Moreover, it has a good performance in terms of distortions in the synchronization signals and it has a good transient performance due amplitude, frequency and angle disturbances. In addition, a frequency adaptation algorithm is proposed for applications where large frequency variations are expected, such as in weak grids. This method can be extended for three-phase systems, applied in three-phase PWM converters. Experimental results using a DSP are given to demonstrate the good performance of the proposed synchronization method.

New hybrid topology of voltage regulation applied in three-phase four-wire system based on induction generator

This paper deals with the development of a new hybrid topology for voltage regulation in micro hydro power station using self-excited induction generator applied in three-phase four-wire systems. The proposed topology is a combination of a three-phase four legs static VAR compensator (SVC) and capacitor banks connected in parallel to the AC voltage bar. It is considered a three wires generator with no accessible neutral point being the neutral terminal for the load created through the neutral terminal of the excitation capacitor and the fourth leg of SVC, which provides the choice to connect the loads either star or delta configurations. A control algorithm and a project for the variable capacitors are proposed based on the specifications of the SVC. The proposed generating system is modeled and simulated in MATLAB. Simulation results and preliminary experimental results are presented to demonstrate the performance of the proposed new hybrid method for the voltage regulation of the self-excited induction generator. In the sequence, simulation results are presented in order to demonstrate the capability of the proposed system for feeding three-phase and single-phase balanced and unbalanced loads, with no distortion of the generated voltages.

Sliding mode current control of DSTATCOM applied to voltage regulation of induction generator based systems

This paper presents the application of the sliding mode (SM) control method applied in the voltage regulation of stand-alone self-excited induction generator (SEIG) based systems under nonlinear and unbalanced loads. For this study, it is considered a three-phase three-wire topology, in which the voltage regulation is done by a distribution static compensator (DSTATCOM). It is proposed a SM controller to be applied in the current control of the DSTATCOM. The control is implemented so that in addition to regulate the voltage, the DSTATCOM can also compensate for harmonics and unbalances in the load currents, improving in this way the overall power quality of the system. The proposed control system is simulated in the software Matlab and implemented on an experimental setup. The test results show the implemented SM current control is able to reduce the harmonic and unbalance content of the generator voltages and currents.

Voltage and frequency regulation of induction generator based system applying proportional-resonant controller

This paper deals with a system control for voltage and frequency regulation in stand-alone generation systems based on self-excited induction generators (SEIG). A three-wire hybrid topology composed by switchable capacitor banks and distribution static compensator (DSTATCOM) is considered. The DSTATCOM is controlled by proportional-resonant-derivative (PRD) controllers in association to proportional-integral (PI) controllers in order to compensate the system reactive power, balance induction generator (IG) currents and compensate harmonic currents. An electronic load controller connected to the three-phase bus guarantee the frequency regulation by the control of active power. Experimental results are presented to demonstrate its performance.