What is an Inverter and How does it work

An inverter is a device to change DC current to AC. It can be used for example to run devices during electric outages or remote areas without electrical service. For example at a remote area if you have solar panel to supply electricity, it would be a DC voltage. You need an inverter to modify this current to an AC current, to power your tools, devices, appliances or equipment, most of which are made to run on AC current, due to its inherent efficiency over DC current when transmitting electricity to power or homes, offices and factories.

An inverter changes the DC current direction, to match the sinusoidal waveform and frequency (as in 50 Hz) of an AC current.

In one sentence, how does an inverter work?

An inverter, has especially arranged paths of current to flow, and does this conversion by rapidly turning on and off the switches on these paths to generate current in wave form, (AC), from steady current (DC).

The components used in an inverter typically are:
Capacitors: They are a passive component of a circuit, which store and release energy when needed in order to smooth out fluctuations.
Transistors: Acts as an on or off switch to control the output
Inductors: Also a passive component like capacitor, an inductor helps stabilizing current and voltage fluctuations, working together with capacitors, by complementing each other.
Controller: It controls the on and off status if switches in a desired pattern, to generate the frequency of AC current we want.

Note that, above we said capacitors and Inductors both help stabilize voltage and current. So how do they exactly differ here, in other words why do we need both ?

Capacitors and Inductors basically complement each other here, for overall efficiency and stability of the circuit.

Capacitors store energy in their electric field. This makes them inherently good for dealing with abrupt voltage changes or fluctuations in other words, voltage regulation, to maintain steady voltage. This change can happen quickly because capacitors have low impedance at high frequencies, and this makes capacitors good at filtering high-frequency noise.

On the other hand inductors are very good at dealing with current changes because they store energy in their magnetic field during current flow. When the current changes, it is countered by the already existing current because of the magnetic field of the inductor, which tends to resist this change at first, and then gradually, smoothly allows it. In other words, inductors are used in current regulation to maintain a steady output of current. This ensures that unstable loads and current spikes are prevented. Because of the inherent slow synchronization nature of inductors with changes in current, in other words because inductors have low impedance at low frequencies, they are good at filtering low frequency noises.

Therefore, together, capacitors and inductors filter noise in voltage and current and smooth those out. This improves the efficiency of the inverter, significantly reduce power losses and ensures that the inverter can deliver stable voltage and current, which is safe to use.

Pipe mapping and repairing robot of CMU

Carnegie Mellon University Robotics Institute Researchers have developed a robot that can crawl inside natural gas pipelines to map them, while also detecting and repairing their leaks when necessary.

The research project, which is near completion, was sponsored by the U.S. Department of Energy (DOE) through the Advanced Research Projects Agency-Energy (ARPA-E) and its Rapid Encapsulation of Pipelines Avoiding Intensive Replacement (REPAIR) program. Upon its application, use of this system will drastically reduce the costs of pipeline leak detection and leak repair processes. 

Image Credit: Carnegie Mellon University

The repair is made by the robot applying resin coating from inside, to seal the crack and can be applied for pipes of any material. The robot has a modular configuration which can be modified, which means flexibility for each application. 

Image Credit: Carnegie Mellon University

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