Active power decoupling methods are developed to deal with the inherent ripple power at twice the grid frequency in single-phase systems generally by adding active switches and energy storage units. They have obtained a wide range of applications, such as photovoltaic (PV) systems, light-emitting diodes (LEDs) drivers, fuel cell (FC) power systems, and electric vehicle (EV) battery chargers, etc. This paper provides a comprehensive review of active power decoupling circuit topologies. They are categorized into two groups in terms of the structure characteristics: independent and dependent decoupling circuit topologies. The former operates independently with the original converter, and the latter, however, shares the power semiconductor devices with the original converter partially and even completely. The development laws for the active power decoupling topologies are revealed from the view of “duality principle,” “switches sharing,” and “differential connection.” In addition, the exceptions and special cases are also briefly introduced. This paper is targeted to help researchers, engineers, and designers to construct some new decoupling circuit topologies and properly select existing ones according to the specific application.

Review of Active Power Decoupling Topologies in Single-Phase Systems

Parameter extraction of solar photovoltaic models using an improved whale optimization algorithm

Comprehensive overview of meta-heuristic algorithm applications on PV cell parameter identification

This paper proposes a new converter for photovoltaic (PV) water pumping or treatment systems without the use of chemical storage elements, such as batteries. The converter is designed to drive a three-phase induction motor directly from PV energy. The use of a three-phase induction motor presents a better solution to the commercial dc motor water pumping system. The development is oriented to achieve a more efficient, reliable, maintenance-free, and cheaper solution than the standard ones that use dc motors or low-voltage synchronous motors. The developed system is based on a current-fed multiresonant converter also known as resonant two-inductor boost converter (TIBC) and a full-bridge three-phase voltage source inverter (VSI). The classic topology of the TIBC has features like high voltage gain and low input current ripple. In this paper, it is further improved with the use of a nonisolated recovery snubber along with a hysteresis controller and the use of a constant duty cycle control to improve its efficiency. Experimental results show a peak efficiency of 91% at a rated power of 210 W for the dc/dc converter plus the three-phase VSI and a peak efficiency of 93.64% just for the dc/dc converter. The system is expected to have a high lifetime due to the inexistence of electrolytic capacitors, and the total cost of the converter is below 0.43 U$/Wp. As a result, the system is a promising solution to be used in isolated locations and to deliver water to poor communities.

Implementation of a High-Efficiency, High-Lifetime, and Low-Cost Converter for an Autonomous Photovoltaic Water Pumping System

Power electronic converter (PEC)-interfaced renewable energy generators (REGs) are increasingly being integrated to the power grid. With the high renewable power penetration levels, one of the key power system parameters, namely reactive power, is affected, provoking steady-state voltage and dynamic/transient stability issues. Therefore, it is imperative to maintain and manage adequate reactive power reserve to ensure a stable and reliable power grid. This paper presents a comprehensive literature review on the reactive power management in renewable rich power grids. Reactive power requirements stipulated in different grid codes for REGs are summarized to assess their adequacy for future network requirements. The PEC-interfaced REGs are discussed with a special emphasis on their reactive power compensation capability and control schemes. Along with REGs, conventional reactive power support devices (e.g., capacitor banks) and PEC-interfaced reactive power support devices (e.g., static synchronous compensators) play an indispensable role in the reactive power management of renewable rich power grids, and thus their reactive power control capabilities and limitations are thoroughly reviewed in this paper. Then, various reactive power control strategies are reviewed with a special emphasis on their advantages/disadvantages. Reactive power coordination between support devices and their optimal capacity are vital for an efficient and stable management of the power grid. Accordingly, the prominent reactive power coordination and optimization algorithms are critically examined and discussed in this paper. Finally, the key issues pertinent to the reactive power management in renewable rich power grids are enlisted with some important technical recommendations for the power industry, policymakers, and academic researchers.

Reactive Power Management in Renewable Rich Power Grids: A Review of Grid-Codes, Renewable Generators, Support Devices, Control Strategies and Optimization Algorithms

In this work it is presented a Current Source Converter (CSC) topology that helps to mitigate double line frequency power ripple (low frequency) effect. Low frequency power ripple presented in single-phase systems propagates through DC-bus converter. This low frequency ripple reduction allows to increase the power converter density by reducing the volume of the DC inductor, without lack of stiffness at the DC-bus. The low frequency mitigation is achieved by using a different single-phase CSC topology that uses three series-connected switches per leg. Thus, it allows independent control for two merged CSCs which share the same DC-bus and the middle switches of the leg. This solution is adequate to connect photovoltaic panels to the electrical grid, among others applications. Evaluation of such a solution by assuming grid modeling is useful and may require powerful simulation tools such as real-time simulator. In order to comply with power processing restrictions, a low frequency model is derived. Performance of both models (high and low frequency) are compared to ensure usability of the low frequency model. Control strategies and modulation are presented. Simulation results are provided to validate the theoretical approach, and real-time simulation results, as well.

Single-phase current source converter with new modulation approach and power decoupling

In this article, a multiphase resonant inverter with vertical aligned coupled coils is proposed for an induction heating application, in which the proposed phase-shift control strategy improves the system power capability. The model for an $n$ coil arrangement is developed using the impedance matrix approach, which allows a circuit representation by means of dependent sources. Each coil is part of a series resonant tank fed by a half-bridge inverter. In particular, the developed converter is evaluated for an $n=2$ case, which is composed by two coils, whose commutation states and the typical waveforms for zero voltage switching operation are addressed in detail. Extensive SPICE simulations are accomplished for validating the analytical model under switching frequency, and duty cycle and phase-shift modulations are contrasted. The model parameters of the coils are obtained applying a nonlinear regression from the experimental data provided by an impedance analyzer. Afterwards, the system feasibility is corroborated using a 2-kW prototype with 97% maximum efficiency under wide load conditions for the aforementioned modulations.

Multiphase Resonant Inverter With Coupled Coils for AC–AC Induction Heating Application

This paper presents two universal active power filters (UAPFs) configurations using single-phase four-leg ac–dc–ac converters. The proposed topologies are used for disturbance compensation in the power supply, such as voltages sags/swells, and to compensate harmonic distortions in the current. The operation of the proposed configurations is compared with the conventional single-phase four-leg UAPF. The harmonic distortions, semiconductor losses, and average switching frequency are used as comparison parameters. Compared to the conventional configuration, the proposed topologies use a transformer with lower power, provide lower average switching, and reduced current total harmonic distortion (THD) and voltage weighted THD. The pulsewidth modulation (PWM) strategy was designed based on a space vector modulation technique, and a control system for the grid current and dc-link bus voltage regulation was also developed. Simulation and experimental results are presented showing the efficiency of the PWM and control strategies and validating the proposed topologies.

Single-Phase Universal Active Power Filter Based on Four-Leg AC–DC–AC Converters

This work presents a single-phase current source converter topology that allows to mitigate typical DC-bus power ripple. Reduction of power ripple at twice of line frequency is one of the key elements to increase power converter density without lack of DC-bus stiffness. In this paper, low frequency ripple mitigation is achieved by adding a third leg connected to the output filter central point. Details of control strategy and modulation are presented. Simulation results are provided to validate the theoretical analysis.

http://ieeexplore.ieee.org/iel7/6624149/6646663/06647417.pdf

Single-phase power compensation in a current source converter

This paper presents a sensorless control scheme for a surface-mounted permanent-magnet synchronous machine (SM-PMSM) using the high frequency voltage signal injection method. The reactances of the high frequency model vary as a function of rotor position and a simple method based on measured high frequency currents and voltages is used to identify these reactances. Using such motor reactances, rotor position and velocity can be estimated. The proposed method is algebraic and does not require accurate knowledge of the initial value of the rotor position. The strategy was verified experimentally using a commercial SM-PMSM machine.

Mauricio B. R. Correa

Papers

Single-phase current source converter with new modulation approach and power decoupling

Multiphase Resonant Inverter With Coupled Coils for AC–AC Induction Heating Application

Single-Phase Universal Active Power Filter Based on Four-Leg AC–DC–AC Converters

Single-phase power compensation in a current source converter

Parameter and Speed Estimation for Implementing Low Speed Sensorless PMSM Drive System Based on an Algebraic Method