Xantrex Technology TC10 - Manual (Page 7)

7
Theory of Operation
High Frequency Power Converter
The Truecharge 10 uses modern high frequency switching power circuits
to convert the alternating current from the utility line to the low voltage
direct current required to charge the battery. The circuits are similar to
those used in power supplies for computers and other modern electronic
equipment.
The alternating current from the utility line is first rectified by diodes to
produce a high voltage direct current.
This direct current is switched at a very high frequency (approximately
75 kHz) to produce pulses of current which are stepped down to a lower
voltage by a small high frequency transformer. The low voltage pulses of
current from the secondary side of the transformer are rectified and
smoothed to create a continuous direct current which is sent to the
battery.
The power switching is performed by power MOSFET transistors. These
transistors also control the charging current and voltage through a
process called pulse width modulation (PWM). The average value of the
voltage or current is controlled by varying the lengths of the pulses of
current. Shorter duration pulses result in lower voltage and current while
longer duration pulses result in higher voltage or current.
The advanced power conversion technology in the Truecharge 10 gives
you several benefits:
• A charger that is smaller and lighter than most other chargers
with similar capabilities. The Truecharge 10 is easy to carry with
you and can be stored or installed in small compartments.
• A totally silent charger. There is none of the “hum” or “buzz”
commonly associated with chargers based on older technology.
• Non-pulsing charging current. While the Truecharge 10 uses
current pulses internally, the output current is filtered so that it is
very smooth. This is the ideal current for charging lead-acid
batteries. Many other chargers produce a pulsating charging
current that does not recharge the battery to its maximum
potential.