Solar power generation--battery and charging circuit

Photocoupler

For the use of such variable power, it is effective to store the energy generated during the day with a battery, and to supply power at the battery at night. The following figure shows the structure of the system. The charging control circuit that takes out the maximum power from the solar cell is described below.

(1) Circuit with only one diode The simplest charging circuit is shown in the figure below. Only one anti-backflow diode is used in series with the battery. Although this method is simple, it is necessary to match the voltage of the solar panel with the battery voltage. The minimum cell voltage of the solar cell is about 0.5V. The actual solar power floor is a plurality of cells connected in series and packaged together. The solar panel voltage of the circuit of Figure 3 should be the same as the maximum charging voltage of the battery.

(2) Charging circuit for improving efficiency As shown in the figure below, a DC-DC converter is inserted between the solar panel and the battery, and the voltage difference between the solar panel and the battery is coordinated by a DC-DC converter. The circuit can control 80% of the open circuit output voltage of the solar panel to achieve high efficiency charging.

A more efficient charging circuit, as shown in the better picture, is a highly efficient charging circuit with maximum power point tracking (MPPT). The circuit detects the solar panel output voltage and current to track the maximum power output (voltage × current = generated power). In order to calculate power, this circuit uses a microprocessor.