How power is generated in satellite:

• Today every satellite uses solar panels for its basic power source. Individual solar cells can generate only small amount of DC power (by converting incident sunlight into electrical energy). So these solar panels are large arrays of photocells connected in various series and parallel circuits to create a powerful source of direct current. The key requirement of the solar panels is to always point towards the sun.

• A key component of the satellite is its power subsystem for power distribution to all subsystem. The figure shows the block diagram of power subsystem with its power distribution.

• Everything on board operates electrically. Most satellites therefore depend entirely upon their power supplies for success. The function of the power subsystem is to provide DC power to all subsystems throughout the life of the spacecraft.

• The basic DC voltage from the solar panels is then conditioned in various ways:

  a) It is typically passed through voltage regulators before being used to power individual electronic circuits. Most electronic equipment works best with fixed stable voltages and therefore regulators are incorporated in most satellite systems.

  b) Some parts of the satellite require higher voltage than those produced by the solar panels. The TWT amplifiers in most communication transponders require thousands of volts for proper operation. Special DC to DC converters are used to translate the lower DC voltage of the solar panels to the higher DC voltage required by the TWTs.

  c) Some circuits of the satellite require Ac voltage so inverters (DC to AC) are used to generate AC voltage.