Research On Output Characteristic And Interface Circuit Of Multiple Piezoelectric Generators In Parallel-connection Mode

Energy scarcity is a serious problem perplexing everyone around the world. In order to alleviate the negative impact of energy crisis on society, scholars from various countries are carrying out research on renewable energy. Environmental vibration energy is one kind of renewable energy which is extensive existing in natural environment. Without the limitation of time and seasons, environmental vibration energy is an abundant kind of clean energy. A piezoelectric vibration system can be designed based on the piezoelectric effect of piezoelectric materials on the purpose of utilizing the environmental vibration energy. To improve the output performance of piezoelectric vibration system, this paper has finished the following works:First, the output power of single piezoelectric generator can hardly offset the power consumption of the interface circuit when connect generator with the piezoelectric interface circuit, so this paper adopts the idea of multiple piezoelectric generators working together. To improve the output performance of multiple piezoelectric generators, four kinds of parallel-connection interface circuits for multiple piezoelectric generators were proposed. The output power in these four kinds of interface circuits was theoretically derived and the influence on it by the phase difference among the exciting forces was studied. Compare the difference of output power characteristics between piezoelectric generator working alone and working in parallel-connection mode.Secondly, the power consumption of the interface circuit can largely affect the working efficiency of the interface circuit. Among all the electronic components in interface circuit, the rectifier diodes play a decisive role in the whole power consumption. The rectifier diodes are often seen as ideal devices in traditional theoretical model. To improve the model accuracy of piezoelectric generator, this paper built a more accurate theoretical model for piezoelectric generator system under the consideration of rectifier diodes’ voltage drop based on the standard circuit. An analytical expression of output power was derived and the simulation analysis about the system’s optimal matching load, the output power of the system and the influence of the rectifier diode on high-power piezoelectric system and low-power piezoelectric system have been done. Again, this paper have designed different kinds of piezoelectric interface circuits from the practical point of view, the proposed interface circuits include:3.3V DC voltage output circuit which can support a low-power sensor, super capacitor discharge circuit suitable for single piezoelectric generator, low-capacity lithium battery discharge circuit suitable for single piezoelectric generator, lithium battery discharge circuit suitable for multiple piezoelectric generators. Through experimental test, we can get a conclusion that the performance of the proposed interface circuits meets the designing requirements.Finally, this paper designed a wind driven rotary piezoelectric generator in which wind energy is converted to environmental vibration energy with the help of mechanical devices and the interaction between the magnets, the environmental vibration energy can be converted to electric energy by using piezoelectric materials. The rotary piezoelectric generator can be divided into nine parts and the parameters of the generator have been optimized through experimental tests. Using the piezoelectric interface circuits proposed in this paper on the rotary piezoelectric generator, the generator can either be a power supply unit or be a piezoelectric storage device.