A power inverter, inverter or invertor is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC). The resulting AC frequency obtained depends on the particular device employed. Inverters do the opposite of rectifiers which were originally large electromechanical devices converting AC to DC.
Distributed generation, also distributed energy, on-site generation (OSG), or district/decentralized energy, is electrical generation and storage performed by a variety of small, grid-connected or distribution system-connected devices referred to as distributed energy resources (DER).
A solar inverter or photovoltaic (PV) inverter is a type of power inverter which converts the variable direct current (DC) output of a photovoltaic solar panel into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or used by a local, off-grid electrical network. It is a critical balance of system (BOS)–component in a photovoltaic system, allowing the use of ordinary AC-powered equipment. Solar power inverters have special functions adapted for use with photovoltaic arrays, including maximum power point tracking and anti-islanding protection.
Power electronics is the application of electronics to the control and conversion of electric power.
A variable-frequency drive (VFD) is a type of motor drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and, depending on topology, to control associated voltage or current variation. VFDs may also be known as 'AFDs', 'ASDs', 'VSDs', 'AC drives', 'micro drives', 'inverter drives' or, simply, 'drives'.
A microgrid is a local electrical grid with defined electrical boundaries, acting as a single and controllable entity. It is able to operate in grid-connected and in island mode. A 'Stand-alone microgrid' or 'isolated microgrid' only operates off-the-grid and cannot be connected to a wider electric power system.
Maximum power point tracking (MPPT) or sometimes just power point tracking (PPT), is a technique used with variable power sources to maximize energy extraction as conditions vary. The technique is most commonly used with photovoltaic (PV) solar systems, but can also be used with wind turbines, optical power transmission and thermophotovoltaics.
Direct torque control (DTC) is one method used in variable-frequency drives to control the torque of three-phase AC electric motors. This involves calculating an estimate of the motor's magnetic flux and torque based on the measured voltage and current of the motor.
Islanding is the condition in which a distributed generator (DG) continues to power a location even though external electrical grid power is no longer present. Islanding can be dangerous to utility workers, who may not realize that a circuit is still powered, and it may prevent automatic re-connection of devices. Additionally, without strict frequency control, the balance between load and generation in the islanded circuit can be violated, thereby leading to abnormal frequencies and voltages. For those reasons, distributed generators must detect islanding and immediately disconnect from the circuit; this is referred to as anti-islanding.
Doubly-fed electric machines also slip-ring generators are electric motors or electric generators, where both the field magnet windings and armature windings are separately connected to equipment outside the machine.
Space vector modulation (SVM) is an algorithm for the control of pulse-width modulation (PWM). It is used for the creation of alternating current (AC) waveforms; most commonly to drive 3 phase AC powered motors at varying speeds from DC using multiple class-D amplifiers. There are variations of SVM that result in different quality and computational requirements. One active area of development is in the reduction of total harmonic distortion (THD) created by the rapid switching inherent to these algorithms.
A solid-state AC-to-AC converter converts an AC waveform to another AC waveform, where the output voltage and frequency can be set arbitrarily.
Bimal Kumar Bose, also known as B. K. Bose, is an electrical engineer, artificial intelligence researcher, scientist, educator, and currently a professor emeritus of power electronics in the Department of Electrical Engineering and Computer Science at the University of Tennessee, Knoxville.
A Z-source inverter is a type of power inverter, a circuit that converts direct current to alternating current. It functions as a buck-boost inverter without making use of DC-DC converter bridge due to its unique circuit topology.
Synchronverters or virtual synchronous generators are inverters which mimic synchronous generators (SG) to provide "synthetic inertia" for ancillary services in electric power systems. Inertia is a property of standard synchronous generators associated with the rotating physical mass of the system spinning at a frequency proportional to the electricity being generated. Inertia has implications towards grid stability as work is required to alter the kinetic energy of the spinning physical mass and therefore opposes changes in grid frequency. Inverter-based generation inherently lacks this property as the waveform is being created artificially via power electronics.
Marcelo Godoy Simões is a Brazilian-American scientist engineer, professor in Electrical Engineering in Flexible and Smart Power Systems, at the University of Vaasa. He was with Colorado School of Mines, in Golden, Colorado, for almost 21 years, where he is a Professor Emeritus. He was elevated to Fellow of the Institute of Electrical and Electronics Engineers (IEEE) for applications of artificial intelligence in control of power electronics systems.
Dan Mircea Ionel is Professor of electrical engineer, the L. Stanley Pigman Chair in Power, and the Director of the SPARK Laboratory and of the PEIK Institute at the University of Kentucky, Lexington, KY. Professor Ionel's research includes the electric machines, wind turbines, power system, applications of power electronics, smart buildings. By the number of citations, he is among the world top 2% highly cited researchers.
Marco Liserre is a University Professor in electrical engineering currently Head of the Chair of Power Electronics at the University of Kiel in Kiel, Germany. He was named a Fellow of the Institute of Electrical and Electronics Engineers (IEEE) in 2013. He is Deputy Director of Fraunhofer ISIT and Founder of ISIT@CAU, 2022.
Remus Teodorescu (02.06.1965) is a professor of Energy Technology at Aalborg University. He holds a degree from 1989 in electrical engineering from the Politehnica University of Bucharest in Romania. In 1994 he received a Ph.D. degree in power electronics from the University of Galati in Romania.
Switching Control Techniques address electromagnetic interference (EMI) mitigation on power electronics (PE). The design of power electronics involves overcoming three key challenges:
- power losses
- EMI
- harmonics
