This paper describes a design of several ship's emergency lighting power supply that power factor is improved and electric power is controlled extensively, and techniques to control and monitor this power supply in remote distance by PC serial communication method.
The remote motoring control system is composed of power factor correction(PFC) circuit, emergency power supply system(EPSS), half bridge(HB) inverter, fluorescent lamp(FL) circuit, microprocessor , multi communication network interface.
PFC circuit makes use of the Buck Type Converter which is a general type. 220[V] AC is rectified in the Full-wave Rectifier(FB) and inputted into PFC circuit, applying the theory of improving power factor by controlling the current in accordance with the peak input voltage using the gate signal from the microprocessor.
EPSS checks the voltage of the emergency backup battery in real time. In case that the voltage of 14[V] or less has been detected for 5[msec] or longer for 3 times successively, charger circuit is connected for battery charging. In voltage 14[V] or higher, charge and discharge circuits are kept disconnected for longer battery life cycle.
Inverter is used to change DC into high frequency AC in order to supply optimal voltage to the lighting and to control the power by controlling the switching frequency. The inverter is HB type which has relatively smaller voltage stress in the elements as well as economy of the element numbers. For the multi communication network interface, IBM PIC and RS485 elements are used, and Visual C++ language is used for monitor control.
Experimental works using proposed system confirm that speedy and stable power to be supplied when main power source cut-off, compared with conventional analog type, and control input up to the range of 30[%] by adjusting pulse frequency of the HB inverter, and achieve 85[%] power factor.
In addition, it has been verified that the control functions including ON-OFF of multiple emergency lighting, 3 step luminous intensity, and real time transmission of voltage, current, and power values were performed appropriately by the remote monitor control.