Jonas Roberto Tibola

Closed loop selective harmonic elimination applied to a grid connected PWM converter with LCL filter

This paper presents the development and design of a control strategy applied to a three-phase grid connected PWM converter with Selective Harmonic Elimination (SHE). First, the transcendental equations of SHE are solved offline and then stored in a look-up table inside of the SHE-Modulator, which is implemented using a FPGA. Synchronism with the grid is obtained using a modified Digital PLL which includes the Modulator with SHE. A discrete model is obtained in dq synchronous frame for the converter with LCL-filter with passive damping and dq PI controllers are used to provide zero steady-state error of grid current. Finally, simulation results are presented to validate the proposed approach.

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.

Modified current pulse charging method for lead-acid batteries based on phase-shift Full-Bridge converter in UPS's family applications

This paper proposes a modified current pulse charging method for lead-acid batteries applied in a family of Uninterruptible Power Supplies with a bank of sealed lead-acid batteries (VRLA). The method is presented based on a phase-shift Full-Bridge converter with galvanic isolation. To confirm the results expected from the theoretical analysis a prototype is developed and experimental results are presented to validate the proposed method.

High efficiency AC photovoltaic module: Efficiency or reduced number of components?

This paper presents the analysis of two AC photovoltaic modules: i) a flyback based, and ii) a full-bridge based. The comparative analysis takes into account the number of semiconductor components, such as switches and diodes, and the delivered power to the grid by each topology. The full-bridge based AC module has one of the highest component count among all the AC modules. In spite of it, it achieves high efficiency and performance. On the other hand the flyback based AC module has one of the fewest component count. So, the goal of the analysis carried out in this paper is to investigate whether it is possible to deliver more power to the grid, even with a higher component count.

Variable speed and stop-start techniques for engine-generators

This paper presents two strategies to decrease overall specific fuel consumption (OSFC) of power generator sets (gensets), which are: variable speed and stop-start operation. In variable speed operation the internal combustion engine (ICE) is able to run in a wide range of rotational speed, therefore providing a degree of freedom to minimize the OSFC of the genset. And in stop-start operation the ICE is turned off when it is operating at low power levels where the ICE exhibit very low efficiency. When the ICE is off the energy is taken from a battery bank. After the battery state of charge decrease to predefined level, the engine is turned on charging the battery and supplying the load. The Genset consist of a Permanent Magnet Synchronous Generator (PMSG), a three phase PWM rectifier connected to the PMSG, a bidirectional boost converter allowing charge and discharge of the battery to the DC-link and a three phase 4-wires 4-legs inverter able to supply unbalanced three phase loads. Simulation results are presented to demonstrate the performance of the proposed genset.

Modified current pulse charging method for lead-acid batteries based on phase-shift full-bridge converter in UPSs family applications

This paper describes a modified current pulse charging method for lead-acid batteries applied to a family of Uninterruptible Power Supplies with a bank of sealed lead-acid batteries (VRLA). The proposed method is presented based on a phase-shift Full-Bridge converter with galvanic isolation. Experimental results are presented to validate the proposed method.

Speed control for ethanol engine of variable speed gensets

This paper presents in details a dynamic model suitable for the design of speed controllers of ethanol fueled internal combustion engine (ICE), applied for variable speed gensets. First, two dynamic models are developed for the ICE: the Time Based model and the Event Based model which is referred to the crankshaft angle. The speed controller design is held through the Event Based model linearization and discretization. This model has advantages for implementation of a speed controller especially regarding the transport delay which becomes fixed. For the ICE speed control it is proposed the use of a proportional integral controller because of its simplicity and ease implementation. The PI design is developed in frequency domain and its stability is ensured by the phase and gain margin. In addition, it is also proposed an integral anti-windup action and a feed forward action aiming at faster transient responses. Experimental results on a 50 kW generator set are provided to validade the model and to demonstrate the system good performance.

Modeling and control of an ethanol Variable Speed Genset

This paper presents in details a dynamic model suitable for the design of speed controllers of ethanol fueled internal combustion engine (ICE), applied to a Variable Speed Genset. First, two dynamic models are developed for the ICE: the Time Based model and the Event Based model which is referred to the crankshaft angle. The speed controller design is held through linearization and discretization of the Event Based model. This model has advantages for implementation of a speed controller especially with regard to the transport delay which becomes fixed. For the ICE speed control it is proposed the use of a proportional integral controller because of its simplicity and ease of implementation. The PI design is developed in frequency domain and its stability is ensured by the phase and gain margin. The Genset also consist of a Permanent Magnet Synchronous Generator (PMSG) and a three phase PWM back-to-back converter that allows grid connection. Modeling and control of the PMSG and the back-to-back converter are also provided. Experimental results are presented to demonstrate the good performance of the system.

System and control method for a variable speed Genset

This paper presents a control method for a Genset that operate at variable speed and preferably using internal combustion engines (ICE) with gaseous or liquid biofuels, but not limited to these. In this method, the control of the DC link is done by the rectifier connected to the Permanent Magnet Synchronous Generator (PMSG). In addition, a maximum efficiency point tracking (MEPT) algorithm presents the best operating point performance criteria considering fuel consumption and/or emissions. Experimental results are presented validating the proposed method.