Battery charging is a complex electrochemical process, in which the discharged electric energy must be replenished from the electric network. The quality of the charging process is critical tothe health and longevity of batteries. As a result, battery chargers play a key role in the life and performance of today’s industrial batteries.

A battery charger is an electrical/electronic device that converts the incoming AC line voltage into a regulated DC voltage to meet the charging needs of the respective battery (see Fig. 1).

Although today’s industrial battery charging market is dominated by Ferro resonant and SCR type chargers, which have been in existence for many years, new high frequency battery charging technologies is making headways into the industrial battery charger markets. This isdue to the higher efficiencies and smaller sizes and weights that a high frequency charger offersover Ferro resonant and SCR types.

High Frequency Chargers:

A frequency battery charger is a class of power supplies that incorporates fully control lable switching power devices, e.g. MOSFETs and IGBTs, and can thus operate at frequencies much higher than line frequencies (few kHz to 100’s of kHz). Unlike SCRs, which are half controlled devices with uncontrollable turn-off, MOSFETs and IGBTs can be fully turned on and off at any instant in time allowing for precise control of the charger output.

A typical high frequency battery charger incorporates a front-end AC-DC rectifier to generate anunregulated DC input voltage, a high frequency (HF) power converter that converts input DC input a high frequency AC voltage, a high frequency isolation transformer to provide output isolation as well as voltage step-down function, and an output rectifier and filtering stage to generate a smooth, very low ripple output DC voltage (see Fig. 5). Pulse Width Modulation

(PWM) is generally employed to regulate the charger output, where the duty cycle of the switching power device (ratio of on-time to switching time) is controlled to control the outputcurrent and/or output voltage of the charger.

The main advantage of high frequency battery chargers over Ferro and SCR chargers is the significant size and weight reduction of the isolation transformer and the subsequent improvement in transformer efficiency. Note that the size of an isolation transformer is inversely proportional to the operating frequency, i.e. the higher the operating frequency, the lower the transformer size. For example, a high frequency transformer operating at 60kHz is ideally 10,000times smaller than a low frequency 60Hz transformer and is much more efficient.

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.