Research on maximum power point tracking control of acoustic energy harvest system

As a kind of renewable energy, acoustic energy can be converted into electrical energy to supply energy for micro-electronic devices, which is a meaningful research topic. In order to keep working at the maximum power point all the time, an acoustic energy harvest system based on the maximum power point tracking (MPPT) control method is proposed. The system is composed of a Helmholtz resonator, a piezoelectric transducer, and an interface circuit, and the interface circuit is composed of a rectifier circuit and a buck-boost circuit. When the acoustic wave enters the cavity, the acousto-electric conversion is carried out through the piezoelectric transducer, and then the DC power is output through the interface circuit. Finally, through the MPPT control program, the system always works at the maximum power point. The theoretical and simulation analysis of the interface circuit is carried out, and the performance of the system is studied and verified by experiments. When the load is constant and the SPL (Sound Pressure Level) increases, the optimal duty cycle fluctuates between 0.1 and 0.3, and the voltage and power of the load increase with the increase of the SPL. When the SPL is 110 dB and the duty cycle is 0.15, the maximum power of the load is 115.2 µW. When the SPL is 110 dB, the optimal duty cycle fluctuates between 0.1 and 0.2. When the load resistance is 30 kΩ, 50 kΩ, 70 kΩ, 90 kΩ, and 110 kΩ, the maximum power of the load is 110.45 µW, 115.2 µW, 104.14 µW, 106.78 µW, and 105.1 µW, respectively.