1. AC-to-DC Converters
The input AC voltage is converted to DC voltage at required levels. A diode bridge rectifier is traditionally used for these applications. But this configuration results in currents that have high peak values and high harmonic content. Boost converters are commonly used to draw currents that are in phase with the AC voltage.
2. DC-to-DC Converters
The DC power input, whether unregulated or regulated, is converted to regulated DC power at the output. Without power electronic converters, it is very difficult to generate variable DC power. With the availability of different configurations of DC-to-DC converters, DC power at desired levels has become indispensable. Buck, boost, and buck-boost converters are three basic converters that can step down, step up, and provide both levels, respectively.
3. DC-to-AC Converters (commonly known as inverters)
The input DC power from batteries is inverted to provide AC power. This AC power is used to control AC motors with precision and efficiency. A combination of AC-to-DC and DC-to-AC converters are used in high-power transmission where two different grids are connected without worrying about synchronization.
4. AC-to-AC Converters (commonly known as cycloconverters)
The AC input that has a variable magnitude and frequency is processed to provide an AC output that has both regulated magnitude and frequency. Wind power generation is a popular application of these types of converters. The output of the wind generator varies in both magnitude and frequency depending on the wind speed. To connect this power to the grid or a load, the voltage and frequency need regulation. This functionality is provided by the AC-to-AC converters.
Other classifications of power converters include the following:
1. Based on the isolation between input and output:
- Non-isolated Converters
- Isolated Converters
2. Based on the type of switching:
- Hard-switched Converters
- Soft-switched Converters
3. Based on the connection to the power grid:
- Grid-connected Converters
- Offline Converters