초록 ▼

A solar cell power source device is disclosed which optimizes the power output of the solar cell by detecting a maximum power point of the solar cell and controlling the duty cycle of a switching transistor in a switching power converter such that the output current of the solar cell follows the max

A solar cell power source device is disclosed which optimizes the power output of the solar cell by detecting a maximum power point of the solar cell and controlling the duty cycle of a switching transistor in a switching power converter such that the output current of the solar cell follows the maximum power point. Also shown is a pulse width modulation controller which multiplies the output voltage of the solar cell by the output current of the solar cell to obtain a power detecting signal, samples the power detecting signal during two different sample periods to determine if the power output is decreasing, and modulating the pulses output to the switching transistor of the switching power converter in order to maintain the power output of the solar cell at the maximum power point.

대표청구항 ▼

[ What is claimed is:] [1.] A solar cell power source device comprising:a solar cell for converting solar energy into a direct current (DC) output voltage;a chopper circuit for receiving the DC output voltage of said solar cell and converting the DC output voltage of said solar cell into a regulated

[ What is claimed is:] [1.] A solar cell power source device comprising:a solar cell for converting solar energy into a direct current (DC) output voltage;a chopper circuit for receiving the DC output voltage of said solar cell and converting the DC output voltage of said solar cell into a regulated DC voltage, wherein said chopper circuit comprises:an inductor coupled in series between an input terminal of the chopper circuit and an output terminal of the chopper circuit, wherein the input terminal of the chopper circuit is coupled to an output terminal of said solar cell and wherein the output terminal of the chopper circuit is configured to output the regulated DC voltage;a diode coupled between the inductor and the output terminal of the chopper circuit such that the diode permits current flow in the direction of the output terminal of the chopper;a switching transistor having first and second power terminals and a control terminal, wherein the first terminal is coupled between the inductor and the diode, and further wherein the control terminal is controlled by the pulse width modulation controller;a current sensing resistor coupled between the second power terminal of the switching transistor and the ground terminal; anda first capacitor coupled between the output terminal of the chopper circuit and the ground terminal;a battery configured to receive the regulated DC voltage from said chopper circuit; anda pulse width modulation controller for receiving the DC output voltage and an output current of said solar cell, detecting a maximum power point of said solar cell responsive to the DC output voltage and the output current, and controlling said chopper circuit so as to maintain the regulated DC voltage of said chopper circuit at a constant level by causing the output current of said solar cell to follow the detected maximum power point, wherein said pulse width modulation controller comprises:maximum power point detecting means for receiving the output voltage of said solar cell and a current detecting signal of said current sensing resistor, and detecting said maximum power point to generate a maximum power point detecting signal;reference signal generating means for integrating said maximum power point detecting signal in order to generate a current command signal;comparing means for comparing said current command signal with said current detecting signal in order to generate an off control signal; andswitch driving means for turning on said switching transistor in response to a clock signal having a predetermined frequency, and turning off said switching transistor in response to said off control signal.