Heverton Pereira - Academia.edu (original) (raw)

Papers by Heverton Pereira

2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015

2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015

2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015

2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015

Revista Da Estatistica Da Universidade Federal De Ouro Preto, 2012

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe), 2015

Dynamic saturation, harmonic compensation, multifunctional photovoltaic inverter and reactive pow... more Dynamic saturation, harmonic compensation, multifunctional photovoltaic inverter and reactive power compensation.

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe), 2015

This paper presents an inverter control scheme, based on proportional-resonant controllers, where... more This paper presents an inverter control scheme, based on proportional-resonant controllers, where the inverter works in multifunctional operation. In this case, the reactive power and harmonic compensation of the load are ancillary services. A resonant control is implemented in stationary reference frame (αβ), where is not necessary the use of a phase-locked loop (PLL). The instantaneous power theory (IPT) is used to detect the harmonic current and reactive power of the load. These components are used as references in the inverter control strategy. Most important fact and less related in literature is the inverter current limitation strategy. Thus, this work introduces a dynamic saturation scheme for a multifunctional three-phase inverter. This strategy possibilities partial or total reactive power and harmonic current compensation without injection of low order harmonics, ensuring that the inverter current does not exceeds the rated current.

2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015

2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015

Single and three-phase photovoltaic inverters are responsible to extract the photovoltaic array p... more Single and three-phase photovoltaic inverters are responsible to extract the photovoltaic array power and inject it into the grid. Due to variations in solar irradiance, inverters have a current margin, which is not explored during the day. Thereby, many works have proposed multifunctional operation. This concept consists in aggregate to the inverter control strategy other functions, such as harmonics and reactive power compensation. However, most important fact and less related in literature is the necessity of techniques to compensate partially reactive power and harmonics of the load, ensuring the inverter work below the rated current. Hence, the present work proposes a current dynamic saturation scheme in order to compensate partially reactive power and harmonics of the load during the multifunctional operation. Simulations show that the dynamic saturation prevents the inverter of inject low-order harmonics while ensuring the operation below the system rated current. By applying the multifunctional operation, the grid current THD is reduced from 104.64% to 1.54% and reactive power is fully compensated, resulting in a considerable grid improvement.

2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015

Photovoltaic (PV) systems have gained prominence in the current context of distributed generation... more Photovoltaic (PV) systems have gained prominence in the current context of distributed generation systems. The fundamental element of a PV grid-connected systems is the power converter. Power converters must be tested and certified according to the international standards, before being commercialized. Therefore, a flexible equipment to test the converters is necessary. This paper presents the modeling and control structure of a solar array simulator (SAS) of 10 kW for testing power converters. The limitations of conventional structures are pointed out and an improved structure based on two converter stages is proposed. The feasibility of the proposed SAS is shown through simulations using the Matlab/Simulink. The simulator is tested for the system connected to resistive loads and to a photovoltaic converter model. The dynamical behavior is evaluated through solar irradiance variations and partial shadowing tests. The results of the proposed structure show flexibility and good levels of power quality.

2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015

In photovoltaic standalone systems it is crucial to absorb most of the available energy. Thus, in... more In photovoltaic standalone systems it is crucial to absorb most of the available energy. Thus, in order to extract the maximum power of a solar panel for a given set of climatic conditions, it is used maximum power point tracker (MPPT). The MPPT consists in a power converter which controls the solar panel voltage. In this context, this work compares the instantaneous and dynamic efficiency of three MPPT algorithms proposed in literature: perturb and observe, dP -perturb and observe and modified perturb and observe used in a photovoltaic standalone systems. The system analyzed is composted by a 48 W solar panel, a battery of 60 Ah and a charger based on a buck converter. During solar irradiance variations the algorithms presented different instantaneous efficiencies, what can produce reduction in energy absorbed during cloudy days.

2015 IEEE Eindhoven PowerTech, 2015

2013 IEEE PES Conference on Innovative Smart Grid Technologies (ISGT Latin America), 2013

A solar panel is influenced by its temperature, usually the lower temperature means that the pane... more A solar panel is influenced by its temperature, usually the lower temperature means that the panel will be more efficient. This paper contains a way to show the temperature along the photovoltaic panel as well as using an algorithm to analyze how this temperature has influenced in the generated power.

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe), 2015

Modular Multilevel Converters (MMC) are the solution of preference in HVDC applications due to mo... more Modular Multilevel Converters (MMC) are the solution of preference in HVDC applications due to modularity, scalability, low losses and low filtering requirement. Carrier-based (PWM) and carrier-less (nearest level control) modulation can be applied. By using advanced sorting methods focusing on keeping the capacitor voltage ripple under some limit, unnecessary switching events are eliminated leading to reduced switching losses. This paper presents a comparison between the steady-state performances in terms of output voltage THD and equivalent switching frequency of the Phase Shifted Carrier PWM and NLC plus sorting methods.

The power generated by a solar panel is directly related to the level of solar irradiance on the ... more The power generated by a solar panel is directly related to the level of solar irradiance on the panel. Thus a system capable of tracking the solar movement improves the efficiency in the generated power. This work presents a study of solar radiation levels and the construction of a sun tracking prototype in order to follow the movement of the sun during the day and increase the power generated by the panel.

The advancement in the use of renewable sources of electricity has been promoting the manufacture... more The advancement in the use of renewable sources of electricity has been promoting the manufacture of wind turbines. This paper analyzes the influence of the insertion of resistance in the rotor of induction machines during voltage sags to improve its operation and presents a new approach. The control strategy uses the Newton's Method, which is a numerical method. A simulation in a wind generator was realized, proving the control efficiency.

Wind power plants are playing an important role in renewable energy generation in this decade. Wi... more Wind power plants are playing an important role in renewable energy generation in this decade. With the enhancements in its technology, mainly based on the aggregation of power electronics, many studies have been carried for evaluating their impact in power quality. Although the Brazilian Electrical System National Operator, who is responsible for transmission and generation system management, has suggested a procedure for such studies, there are many aspects related to the simulation algorithm and the electrical components modelling that are left aside from the problem, without an adequate reasoning of its impacts on power quality simulation results. This paper presents a detailed analysis of a wind farm impact on the Brazilian distribution system power quality. Both internal (wind park elements) and external (power grid) components modelling effects on harmonic propagation are considered, and these effects are evaluated

This paper evaluates the harmonic propagation due to wind farms integration. Time domain and freq... more This paper evaluates the harmonic propagation due to wind farms integration. Time domain and frequency domain analysis are compared and the advantages of each methodology are shown. The study considers the aggregated effect of several static power converters, including their control and filter, as well as the impact on the system of incoming generators. Each domain analysis contains its difficulties and advantages and results of both domains from the same system are presented and discussed.

This work proposes the use of passivity-based control in a photovoltaic system connected to the g... more This work proposes the use of passivity-based control in a photovoltaic system connected to the grid with energy storage unit. It is used two boost converters: the bidirectional acts as Maximum Power Point Tracker (MPPT), controlling power flow between the battery bank and the others components, and the unidirectional topology maintains the voltage at the inverter DC bus in the determined value. The single-phase inverter connects the system to the grid. Simulation results show that the passivity-based control allows the panel to work in the maximum power point and has a good rejection of disturbances related to the current injection of the inverter in the grid.

2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015

2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015

2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015

2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015

Revista Da Estatistica Da Universidade Federal De Ouro Preto, 2012

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe), 2015

Dynamic saturation, harmonic compensation, multifunctional photovoltaic inverter and reactive pow... more Dynamic saturation, harmonic compensation, multifunctional photovoltaic inverter and reactive power compensation.

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe), 2015

This paper presents an inverter control scheme, based on proportional-resonant controllers, where... more This paper presents an inverter control scheme, based on proportional-resonant controllers, where the inverter works in multifunctional operation. In this case, the reactive power and harmonic compensation of the load are ancillary services. A resonant control is implemented in stationary reference frame (αβ), where is not necessary the use of a phase-locked loop (PLL). The instantaneous power theory (IPT) is used to detect the harmonic current and reactive power of the load. These components are used as references in the inverter control strategy. Most important fact and less related in literature is the inverter current limitation strategy. Thus, this work introduces a dynamic saturation scheme for a multifunctional three-phase inverter. This strategy possibilities partial or total reactive power and harmonic current compensation without injection of low order harmonics, ensuring that the inverter current does not exceeds the rated current.

2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015

2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015

Single and three-phase photovoltaic inverters are responsible to extract the photovoltaic array p... more Single and three-phase photovoltaic inverters are responsible to extract the photovoltaic array power and inject it into the grid. Due to variations in solar irradiance, inverters have a current margin, which is not explored during the day. Thereby, many works have proposed multifunctional operation. This concept consists in aggregate to the inverter control strategy other functions, such as harmonics and reactive power compensation. However, most important fact and less related in literature is the necessity of techniques to compensate partially reactive power and harmonics of the load, ensuring the inverter work below the rated current. Hence, the present work proposes a current dynamic saturation scheme in order to compensate partially reactive power and harmonics of the load during the multifunctional operation. Simulations show that the dynamic saturation prevents the inverter of inject low-order harmonics while ensuring the operation below the system rated current. By applying the multifunctional operation, the grid current THD is reduced from 104.64% to 1.54% and reactive power is fully compensated, resulting in a considerable grid improvement.

2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015

Photovoltaic (PV) systems have gained prominence in the current context of distributed generation... more Photovoltaic (PV) systems have gained prominence in the current context of distributed generation systems. The fundamental element of a PV grid-connected systems is the power converter. Power converters must be tested and certified according to the international standards, before being commercialized. Therefore, a flexible equipment to test the converters is necessary. This paper presents the modeling and control structure of a solar array simulator (SAS) of 10 kW for testing power converters. The limitations of conventional structures are pointed out and an improved structure based on two converter stages is proposed. The feasibility of the proposed SAS is shown through simulations using the Matlab/Simulink. The simulator is tested for the system connected to resistive loads and to a photovoltaic converter model. The dynamical behavior is evaluated through solar irradiance variations and partial shadowing tests. The results of the proposed structure show flexibility and good levels of power quality.

2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015

In photovoltaic standalone systems it is crucial to absorb most of the available energy. Thus, in... more In photovoltaic standalone systems it is crucial to absorb most of the available energy. Thus, in order to extract the maximum power of a solar panel for a given set of climatic conditions, it is used maximum power point tracker (MPPT). The MPPT consists in a power converter which controls the solar panel voltage. In this context, this work compares the instantaneous and dynamic efficiency of three MPPT algorithms proposed in literature: perturb and observe, dP -perturb and observe and modified perturb and observe used in a photovoltaic standalone systems. The system analyzed is composted by a 48 W solar panel, a battery of 60 Ah and a charger based on a buck converter. During solar irradiance variations the algorithms presented different instantaneous efficiencies, what can produce reduction in energy absorbed during cloudy days.

2015 IEEE Eindhoven PowerTech, 2015

2013 IEEE PES Conference on Innovative Smart Grid Technologies (ISGT Latin America), 2013

A solar panel is influenced by its temperature, usually the lower temperature means that the pane... more A solar panel is influenced by its temperature, usually the lower temperature means that the panel will be more efficient. This paper contains a way to show the temperature along the photovoltaic panel as well as using an algorithm to analyze how this temperature has influenced in the generated power.

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe), 2015

Modular Multilevel Converters (MMC) are the solution of preference in HVDC applications due to mo... more Modular Multilevel Converters (MMC) are the solution of preference in HVDC applications due to modularity, scalability, low losses and low filtering requirement. Carrier-based (PWM) and carrier-less (nearest level control) modulation can be applied. By using advanced sorting methods focusing on keeping the capacitor voltage ripple under some limit, unnecessary switching events are eliminated leading to reduced switching losses. This paper presents a comparison between the steady-state performances in terms of output voltage THD and equivalent switching frequency of the Phase Shifted Carrier PWM and NLC plus sorting methods.

The power generated by a solar panel is directly related to the level of solar irradiance on the ... more The power generated by a solar panel is directly related to the level of solar irradiance on the panel. Thus a system capable of tracking the solar movement improves the efficiency in the generated power. This work presents a study of solar radiation levels and the construction of a sun tracking prototype in order to follow the movement of the sun during the day and increase the power generated by the panel.

The advancement in the use of renewable sources of electricity has been promoting the manufacture... more The advancement in the use of renewable sources of electricity has been promoting the manufacture of wind turbines. This paper analyzes the influence of the insertion of resistance in the rotor of induction machines during voltage sags to improve its operation and presents a new approach. The control strategy uses the Newton's Method, which is a numerical method. A simulation in a wind generator was realized, proving the control efficiency.

Wind power plants are playing an important role in renewable energy generation in this decade. Wi... more Wind power plants are playing an important role in renewable energy generation in this decade. With the enhancements in its technology, mainly based on the aggregation of power electronics, many studies have been carried for evaluating their impact in power quality. Although the Brazilian Electrical System National Operator, who is responsible for transmission and generation system management, has suggested a procedure for such studies, there are many aspects related to the simulation algorithm and the electrical components modelling that are left aside from the problem, without an adequate reasoning of its impacts on power quality simulation results. This paper presents a detailed analysis of a wind farm impact on the Brazilian distribution system power quality. Both internal (wind park elements) and external (power grid) components modelling effects on harmonic propagation are considered, and these effects are evaluated

This paper evaluates the harmonic propagation due to wind farms integration. Time domain and freq... more This paper evaluates the harmonic propagation due to wind farms integration. Time domain and frequency domain analysis are compared and the advantages of each methodology are shown. The study considers the aggregated effect of several static power converters, including their control and filter, as well as the impact on the system of incoming generators. Each domain analysis contains its difficulties and advantages and results of both domains from the same system are presented and discussed.

This work proposes the use of passivity-based control in a photovoltaic system connected to the g... more This work proposes the use of passivity-based control in a photovoltaic system connected to the grid with energy storage unit. It is used two boost converters: the bidirectional acts as Maximum Power Point Tracker (MPPT), controlling power flow between the battery bank and the others components, and the unidirectional topology maintains the voltage at the inverter DC bus in the determined value. The single-phase inverter connects the system to the grid. Simulation results show that the passivity-based control allows the panel to work in the maximum power point and has a good rejection of disturbances related to the current injection of the inverter in the grid.