Fig. 1. Diagram of circuit

Fig. 2. Diagram of control circuit

Fig. 3. ADP5091 PCB circuit diagram

Fig. 4. Flow chart of the improved algorithm that combines the PID algorithm and state machine control with three states

Fig. 5. H bridge control circuit

Fig. 6. Transient U/Ivariation in the PWM and TEC devices

Fig. 7. Circuit of temperature control and energy feedback system.

Fig. 8. Experimental diagram of photovoltaic power generation unit

Fig. 9. Relationship between the light intensity of a single photovoltaic panel and the generated current and voltage

Fig. 10. Computer display interface

Fig. 11. Experimental platform

Fig. 12. Current data of charging and discharging battery pack

Fig. 13. The data comparison diagram of the traditional PID and the control algorithm of this system