In the future, renewable energy will be large percentage in electric energy because of deepening of climate change and depletion of fossil fuel. Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, waves and geothermal heat, which are renewable.
There are 440V electric source and 220V in ship. A 440V source is used in driving power system such as crane and winch on deck, a 220V source is used in driving air compressor, pump and control devices in engine room.
Producing of electric energy using solar cell may be available in ship, but large size solar cell may be difficult to use.
In this paper, we make power converter system(PCS) that can meet the THD(Total harmonic distortion) condition(THD of voltage and current should be lower than 8% and 5%, respectively, and a single harmonic should be less than 3%) which is one of the grid-connected regulations for ship, and make power line modem(PLM) which PCS conditions can be monitored in realtime from remote distance.
PCS is made up of gate-level-shifter, single phase inverter(2 level or 3 level), LC-filter, zero crossing and phase detector, TMS320F2812 microprocessor(MCU).
Output AC square wave voltage of a inverter which is controlled by PWM pulse programmed by the MCU is converted with 220V and 60Hz sine wave voltage through L-C filter, and it is connected when inverter output and grid are in phase each other.
As a result, it shows that voltage and current THD of 2 level inverter is 2.7% and 1.9%, respectively, and voltage and current THD of 3 level inverter is 1.7% and 1.8%, respectively. it is confirmed that both of the inverter satisfy the condition, and also the states of system is monitored by using power line communication.