Most of the power conversion applications consist of an AC to DC conversion stage and this DC output is then used for further stages. An AC to DC converter is an integral part of most of the electronic equipment as most of these equipment are DC powered [1]. Generally to convert AC to DC a diode bridge rectifier is used. To reduce the ripple in the output voltage a suitable filter capacitor is used at the rectifier output. The filter capacitor draws a peaky current from the supply, as it charges only for a short duration in a half cycle. Hence the current drawn by a diode rectifier is non-sinusoidal in nature. Due to the non-sinusoidal nature of the input current, THD will be very high and input power factor also will be low

PWM rectifier is an AC to DC power converter, that is implemented using forced commutated power electronics devices like insulated gate bipolar transistors (IGBT) or gate turn-off thyristors (GTO) that are characterized by switch mode operation. The capability of forming sinusoidal currentsis provided by the introduction of the sophisticated technique called pulse-width modulation (PWM). This technique provides the sequences of width-modulated pulses to control power switches. Many PWM techniques have been developed according to special requirements and optimization criteria.

The choice of the particular PWM technique arises from the desired performance of the synchronous rectifiers. Generallypulse-width modulation techniques for frequency converters may be classified as carrier-based sinusoidal PWM,Hysteresis-Band PWM, and space vector PWM, selected harmonic elimination PWM, minimum current ripple PWM,sinusoidal PWM with instantaneous current control andrandom PWM. The basic features of PWM rectifier as follows are bi-directional power flow, input current is nearly sinusoidal, regulation of input power factor to unity and stabilization of DC-link voltage (or current).Today, insulatedgate bipolar transistors are typical switching devices.

Different from diode bridge rectifiers, PWM rectifiers achieve bidirectional power flow. In frequency converters this property makes it possible to perform regenerative braking.PWM rectifiers are also used in distributed power generation applications, such as micro turbines, fuel cells and wind mills.

The major advantage of using pulse width modulation technique is the reduction of higher order harmonics and we can also control the magnitude of the output voltage. We can also improve the power factor by forcing the switches to follow the input voltage waveform using a phase locked loop.

If you have any requirements or any kind of query regarding the Battery charger solutions for your applications, feel free to communicate with our dedicated team at any time at marketing@everexceed.com.