A primary–secondary triboelectric nanogenerator with charge excitation shift in a wind-driven alternating operating mode

Abstract

Triboelectric nanogenerators (TENGs) that can harvest energy from the environment have seen rapid development in recent years. The charge excitation method can increase the TENG performance effectively, but it requires the pump TENG and main TENG to work together, which requires greater rotary torque. Herein, a primary–secondary TENG (PS-TENG) is proposed that can shift its operating mode automatically based on rotational speed to reduce rotary torque in slow mode or realize charge excitation in fast mode. It has a primary block that comprises the P-TENG and a voltage conditioning circuit, a secondary block that contains the S₁-TENG and S₂-TENG, and a two-channel charge excitation circuit. The secondary block is suspended in slow mode to reduce rotary torque. In fast mode, the voltage conditioning circuit can enhance the voltage of the P-TENG for charge excitation, and the two-channel charge excitation circuit enables the S₁-TENG and S₂-TENG to achieve charge excitation and output in turn. The P-TENG can produce an open-circuit voltage of 100 V and transferred charges of 225 nC, and the corresponding values for the S₁-TENG and S₂-TENG are 16 V, 15 nC and 14 V, 14 nC, respectively. With charge excitation by the P-TENG, the transferred charges of the S₁-TENG and S₂-TENG can reach 1.2 μC and 0.6 μC, and their peak powers are 8.7 mW and 3.8 mW, respectively. Furthermore, when driven by wind energy, the PS-TENG can power 320 LEDs or a hygrothermograph steadily. This work has practical application prospects and provides a new method to realize automatic charge excitation shift.