How does an Inverter work | Inverter Circuit Principle


Special electronic power devices called inverters are used to convert direct current and alternating current. (How does an Inverter work)   Often, an inverter converts a DC voltage of one magnitude into an AC voltage of another magnitude. 

Thus, an inverter is a generator of periodically varying voltage, while the voltage waveform can be sinusoidal, close to sinusoidal, or pulsed. Inverters are used as independent devices and as part of uninterruptible power supply systems (UPS). )


How does an inverter work 

Inverter works on charging and discharging. In the absence of electricity, it uses the energy of the battery to convert it into an alternating current supply and when the power comes, it starts charging the battery. 

In order to charge the battery, the inverter bypasses the output supply, that is, during charging, all the load in your house goes to the main supply, which ends the load on the battery and it starts charging. 


Inverter frequency and rotation speed 

Inverter devices are often used to convert alternating current from an outlet to any frequency or voltage.

The voltage and frequency to be supplied from the outlet is set to 100V, 50Hz in eastern Japan and 100v, 60Hz in western Japan, (Inverter Device Configuration) and the rotation speed of the motor is determined by the frequency, (Inverter Circuit Principle)  so the bus will continue to connect the outlet and the motor directly to rotational speed. It cannot be changed. 

Therefore, the rotation speed of the motor is changed by changing the frequency using an inverter device. 

How does an Inverter work, Inverter Circuit Principle

Inverter Device Configuration 

How does the inverter device change the frequency? The inverter device consists of three elements: a “converter circuit” that converts alternating current into direct current, a “capacitor”, and an “inverter circuit”.

First, the converter circuit converts the alternating current into direct current, and the capacitor is repeatedly charged and discharged to produce a steady direct current. Next, the inverter circuit converts the direct current into alternating current at an arbitrary frequency or voltage and outputs it. 


Inverter Circuit Principle 

Explain the principle of operation of inverter circuit on the basis of circuit diagram: which connects four switches as shown in the figure below. Inverter circuit converts direct current into alternating current.

Connect a DC power supply to the circuit, and when switches are ON for the load, AND OFF, AND IF AND OFF, and ON at regular intervals. When repeated, the direction current flowing through the load is switched and outputs with positive and negative voltages, creating an alternating current. This technique is the “switching technique”.

Circuits using switching technology can also convert alternating current into DC. When the switches are closed when the voltage is in the positive direction, and the switches are closed when the voltage is in the negative direction, current always flows in the same direction for the load. 

How does an Inverter work, Inverter Circuit Principle

Principle of switching power supply 

The principle of an inverter that can produce electrical power independently by operating and controlling a switch at high speed is also used for energy saving and miniaturization of converters. A converter that uses switches to convert power is called a “switching power supply”. 

Electronic components require a steady direct current with low voltage fluctuations. Previously, a type of “AC adapter” called a linear power supply was used to convert home AC power to low voltage and direct current. Adapters for game consoles and laptops will be easy to understand. 

The converter using a switching circuit has changed this significantly. In a converter using a switching circuit, the voltage is not reduced at the start, but is passed through the switching circuit.

The direction of the alternating current is adjusted by the switching circuit, and then the voltage is converted. However, in general, rectified electricity cannot be converted into voltage by a transformer. 

How does an Inverter work, Inverter Circuit Principle

Therefore, it is converted into a pulse wave in which a constant voltage flows through a semiconductor element intermittently. It looks like a pseudo alternating current, and the transformer can do voltage conversion. In addition, since the frequency ranges from several tens of kHz to several hundreds of kHz at this time, one advantage is that the transformer size can be smaller. This has resulted in a smaller and lighter converter.

Linear power supplies first reduce the voltage of incoming electricity through a transformer. After that, the rectification was done to replace the electricity flowing only on one side, through the circuit of the silicon diode, and was smoothed by capacitors and led to the circuit of the electronic device. 

Since a large iron core is used for this transformer, the traditional AC adapter was larger and heavier. 


(How does an Inverter work | Inverter Circuit Principle)



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