A Hybrid Estimator for Active/Reactive Power Control of Single-Phase Distributed Generation Systems With Energy Storage

Abstract

This paper presents a new active/reactive power closed-loop control system for a hybrid renewable energy generation system used for single-phase residential/commercial applications. The proposed active/reactive control method includes a hybrid estimator, which is able to quickly and accurately estimate the active/reactive power values. The proposed control system enables the hybrid renewable energy generation system to be able to perform real-time grid interconnection services such as active voltage regulation, active power control, and fault ride-through. Simulation and experimental results demonstrate the superior performance of the proposed closed-loop control system.

A Digital Control System for UPS Systems With Smart-Grid Capability

“…LI batteries are very sensitive to low-frequency current ripples and they can only safely handle very small amounts of ripples [28][29][30][31]. Apart from disastrous effects on the batteries, the existence of these current ripples may have a deleterious functional impact on the transient performance of the UPS system and cause reduced conversion efficiency [32][33][34][35]. Thus, in the future UPS systems, the current ripple should be suppressed in order to protect the batteries and ensure the reliability and performance of the system.…”

A novel single-phase five-level transformer-less photovoltaic (PV) inverter

“…N the past decades, new energy power generations, such as photovoltaic (PV), have rapidly developed due to their unique advantages in little pollution and emission [1], [2]. The multilevel transformer-less inverters play an important role in the single-phase low-power PV system due to their small size and weight, low cost, and high efficiency [3], [4].…”

Model-Based Predictive Current Control Method with Constant Switching Frequency for Single-Phase Voltage Source Inverters

“…One of the main objectives of single-phase converters and inverters is to synthesize a high-quality ac-side sinusoidal current tracking a reference current, to transfer the power required by a variety of systems. For generating a sinusoidal line or load current with low harmonic distortion, control methods for the single-phase converters or inverters usually handle the ac-side sinusoidal current [4][5][6][7][8][9]. The current control methods, based on proportional-integral (PI) controllers, in [4], have been generally utilized; however, steady-state current errors exist in the ac-side current because of exposure of the PI controller to low-frequency fundamental components.…”

“…The current control methods, based on proportional-integral (PI) controllers, in [4], have been generally utilized; however, steady-state current errors exist in the ac-side current because of exposure of the PI controller to low-frequency fundamental components. In addition to the PI-controller-based current control methods to eliminate the steady-state error, numerous approaches have been proposed to reduce current errors, such as hysteresis control [5], deadbeat control [6], proportional-resonant (PR) control [7], voltage-oriented control [8], and predictive control [9]. In particular, the predictive control method has been widely used to control the ac-side current of single-phase converters [10], inverters [11], and other topologies [12,13] as a simple and effective technique due to the development of digital signal processors with low cost and high performance [14][15][16].…”