A power converter or inverter is a piece of power electronics that converts direct current (DC) to alternating current (AC) (AC). The resulting alternating current frequency is determined by the equipment used. Inverters provide the reverse function of rectifiers, which were initially massive electromechanical devices that converted alternating current to direct current.
The design of the specific device or circuitry determines the input voltage, output voltage and frequency, and overall power handling. The inverter does not generate any electricity; it is supplied by the DC source.
A power inverter can be wholly electronic or a combination of mechanical and electronic circuitry (such as rotating equipment). Moving parts are not used in the conversion process of static inverters.
Power inverters are typically utilized in electrical power applications with large currents and voltages; oscillators are circuits that provide a similar job for electronic signals with very low currents and voltages. Rectifiers are circuits that perform the reverse purpose, converting AC to DC.
A typical power inverter device or circuit necessitates a steady DC power source capable of generating enough current to meet the system's desired power demands. The input voltage is determined by the inverter's design and purpose. Here are several examples:
- 12 V DC, for smaller consumer and commercial inverters that typically run from a rechargeable 12 V lead acid battery or automotive electrical outlet.
- 24, 36, and 48 V DC, which are common standards for home energy systems.
- 200 to 400 V DC, when power is from photovoltaic solar panels.
- 300 to 450 V DC, when power is from electric vehicle battery packs in vehicle-to-grid systems.
- Hundreds of thousands of volts, where the inverter is part of a high-voltage direct current power transmission system.
Even when the load that the inverter is driving changes, the AC output voltage of the inverter is frequently controlled to be the same as the grid line voltage, typically 120 or 240 VAC at the distribution level. As a result, the inverter may power a variety of devices built for ordinary line power.
Selectable or continuously changeable output voltages are also available on some inverters.
A power inverter's overall power rating is usually represented in watts or kilowatts. This defines the power available to the device that the inverter is operating and, indirectly, the power required from the DC source. Smaller popular consumer and commercial devices that replicate line power typically range in output from 150 to 3000 watts.
Not all inverter applications are concerned exclusively or primarily with power distribution; in other cases, the frequency and/or waveform features are utilised by the next circuit or device.