Generation Control Circuit Research Articles

Small-Signal Model of the NPC + GCC Multilevel Transformerless Inverter in Single-Phase Photovoltaic Power Systems

Photovoltaic transformerless inverters are very efficient and economical options for solar-power generation. The absence of the isolation transformer improves the converters’ efficiency, but high-frequency voltage to ground can appear in the photovoltaic string poles. The high capacitance to ground of the photovoltaic generator leads to undesirable high-leakage currents. Using half-bridge topologies dramatically reduces the leakage to ground, and using a multilevel half-bridge inverters improves the output quality compared with classical inverters. The neutral point clamped + generation control circuit (NPC + GCC) topology is a multilevel single-phase transformerless inverter capable of tracking the maximum power point of two photovoltaic sources at the same time. This paper presents the control structure and the dynamic modeling of the NPC + GCC inverter. The pulse-width modulated (PWM) switch model in continuous conduction mode (CCM) was used to obtain the small-signal model of the two switching converters that make up the inverter. The resulting dynamic model was used to quantify the stability margins of both converters’ current and voltage loops.

Design of Solar Energy Photoelectric Storage Comprehensive Application Experimental Device

This experimental device is composed of the battery characteristics test of the solar cell, rotating and leveling of the solar panel, photoelectric complementary power supply, battery capacity display and charging/capacity and internal resistance test unit. The battery characteristics test unit includes variable resistance circuit, modulation circuit, LED drive circuit and light intensity measurement and display circuit design. The rotating and leveling of the solar panel unit includes wind and rain sensor input, master control of MCU, vertical axis rotation, horizontal axis swing rotation, voice warning and so on. The photoelectric complementary power supply unit includes the charge and discharge controller, inverter, DC/AC load and control circuit. In addition, the battery capacity display unit includes signal input, analog-to-digital conversion and LED display/voice alarm circuit design. The battery charging /capacity and internal resistance test unit includes voltage regulator, constant current generation circuit, voltage detection, display circuit and control circuit. In this paper, the experimental contents and methods which can be carried out by the device are designed. The experiment of the device has the characteristics of rich knowledge integration, strong comprehensiveness and a flexible combination of contents.

Cell equalizer for recycling batteries from hybrid electric vehicles

The rise of electric vehicles (EVs) and hybrid electric vehicles (HEVs) has resulted in increases in battery toxic waste. Although the powering and capacity characteristics of batteries deteriorate after use in EVs and HEVs, they usually retain enough potential for reuse as power sources in home energy systems, whose power requirements are much lower than those of EVs and HEVs. This study proposes an active cell equalizer that balances the state of charge (SOC) of nickel–metal hybrid (NiMH) batteries recycled from HEVs. In the proposed cell equalizer, two different circuits, e.g., a generation control circuit (GCC) and a power-decoupling circuit are integrated. Excessive energy is automatically transferred from a high-SOC cell to a low-SOC cell through the GCC. The power-decoupling circuit lowers the power pulsation caused by the single-phase DC/AC inverter. This reduces the low-frequency ripple current flowing into the battery pack, ensures safe operation and prolongs the lifecycle of the batteries. A prototype circuit with a three-stage battery pack is implemented in the discharging state and the obtained experimental results are analyzed to verify the equalizer functionality.

AGC of multi area power system based PSO under deregulated conditions

In This research PIDF (Proportional Integral Derivative with Filter) is suggested to control the ACE (area control error) signal of automatic generation control circuit (AGC) for two-area multi units system under deregulated conditions, each area consist of two thermal reheat units with physical GRC (generating rate constrain). The parameters of the PIDF controller are tuned using PSO (particle swarm optimization) technique. To improve the system performance, Redox Flow Batteries (RFB) is presented in one area and one of FACTS components IPFC (Inter Line Power Flow Controller) is installed in tie line. The performance of the proposed controller is assessed under different working conditions of deregulated power market. Finally, a comparison will be made on the system response when testing with varying the load conditions and system parameter through MATLAB environment 2015Rb.

DESIGN AN AUTOMATIC MAXIMUM POWER POINT TRACKER (MPPT) COUPLED WITH SOLAR CELLS ARRAY

The aim of this paper is the design of an automatic voltage regulator device for regulating the load voltage supplied by solar cells array (SCA). The device contains DC control circuit (DCCC) and automatic voltage regulating circuit. This circuit senses any deviation of load voltage from that at maximum power point (MPP) of SCA. As the voltage deviated away from the voltage at MPP, the circuit changes its state. Then, the operation of the circuit at this instant changes the performance of DCCC triggering circuit. Consequently, the (DCCC) will return back the load voltage deviated to that equal to the voltage at MPP. Through this paper the proposed construction of the automatic control voltage device is illustrated. Its design procedures as will as its performance are investigated. The proper operation of the proposed regulator shows that it’s very suitable for coupling with photovoltaic power systems and agricultural loads (DC Irrigation pump). In the present paper, a novel circuit, referred to as the generation control circuit (GCC), which enables maximum power to be obtained from all of the PV modules even if some of the modules are prevented from receiving light. The proposed circuit enables the individual PV modules to operate effectively at the maximum power point tracking, irrespective of the series connected PV module system. In addition, the total generated power is shown experimentally to increase for the experimental set-up used in the present study.

Grid‐tie inverter topology with maximum power extraction from two photovoltaic arrays

This study presents a transformerless topology for a grid-tied single-phase inverter capable of performing the simultaneous maximum power point tracking of two independent and series connected photovoltaic sources. This topology is derived from the neutral point clamped multilevel inverter in half-bridge configuration. The use of a half-bridge topology reduces the leakage current to very low values, whereas the multilevel topology presents an output voltage quality similar to that of a full-bridge inverter. To simultaneously track the maximum power of both photovoltaic sources, a generation control circuit is used. With this topology, it is possible to improve the performance of the converter under partial shadowing conditions, very common in photovoltaic facilities operating in residential areas. A 5 kW prototype of this topology has been implemented and tested in the laboratory.

단상 인버터를 이용한 새로운 태양광 에너지 변환 시스템 구현

본 논문은 새로운 태양광 에너지 변환 기술에 의한 연계형 단상 인버터 제어기술을 나타내었다. 최대전력 점 추적제어는 두 부스터 컨버터의 MOSFET 스위치 제어 발생회로에 기초하고 단상 인버터는 풀 브리지의 4개 IGBT 스위치에 의해 전류 추종제어 된다.<BR> PV 모듈의 발생전력 제어회로는 PV 모듈의 출력 전압, 전류 검출에 의해 최대전력 점 제어한다.<BR> 결국 PV 모듈 양단은 인버터 입력전압으로 낮은 리플 전압을 유지하고 출력은 증가한다.<BR> 제안한 태양광 인버터 시스템의 효과가 시뮬레이션과 실험을 통하여 입증되었다.

A novel high-performance utility-interactive photovoltaic inverter system

This paper presents a novel photovoltaic inverter that cannot only synchronize a sinusoidal AC output current with a utility line voltage, but also control the power generation of each photovoltaic module in an array. The proposed inverter system is composed of a half-bridge inverter at the utility interface and a novel generation control circuit which compensates for reductions in the output power of the system that are attributable to variations in the generation conditions of respective photovoltaic modules. The generation control circuit allows each photovoltaic module to operate independently at peak capacity, simply by detecting the output power of the system. Furthermore, the generation control circuit attenuates low-frequency ripple voltage, which is caused by the half-bridge inverter, across the photovoltaic modules. Consequently, the output power of the system is increased due to the increase in average power generated by the photovoltaic modules. The effectiveness of the proposed inverter system is confirmed experimentally and by means of simulation.

Generation control circuit for photovoltaic modules

Photovoltaic modules must generally be connected in series in order to produce the voltage required to efficiently drive an inverter. However, if even a very small part of photovoltaic module (PV module) is prevented from receiving light, the generation power of the PV module is decreased disproportionately. This greater than expected decrease occurs because PV modules which do not receive adequate light cannot operate on the normal operating point, but rather operate as loads. As a result, the total power from the PV modules is decreased if even only a small part of the PV modules are shaded. In the present paper, a novel circuit, referred to as the generation control circuit (GCC), which enables maximum power to be obtained from all of the PV modules even if some of the modules are prevented from receiving light. The proposed circuit enables the individual PV modules to operate effectively at the maximum power point tracking, irrespective of the series connected PV module system. In addition, the total generated power is shown experimentally to increase for the experimental set-up used in the present study.