高效磁电弹性复合振动能量收集的若干关键问题研究

The problem of long-term reliable power supply for wireless sensor network (WSN) nodes stems from the limited battery life and inconvenient replacement after battery exhaustion. To address the above problem, the technology of ambient vibration energy harvesting has begun to spring up and been a research hotspot recently. Around some key problems of efficient magneto-electro-elastic hybrid vibration energy harvesting (MEE-HVEH), three aspects are researched in this project. First, the efficient energy conversion problem is researched aiming to improve the energy conversion efficiency of MEE-HVEH system. Hence, the system-level modeling of the whole system including the MEE converter and power extraction interface is carried out, which enables the two parts to be globally optimized at the same level, thereby revealing the inherent working mechanism of MEE-HVEH system. Second, the problem of multi-source power extraction under multi-physics coupling constraints is researched aiming to improve the final output power of MEE-HVEH system. Hence, the multi-source power extraction method based on multiple load impedance matching and the multi-source power extraction method based on optimal control of back coupling effect are proposed. And, the corresponding interface circuits and control strategies are also developed. Finally, the proposed theoretical methods and key technologies are verified through system-level performance test on the MEE-HVEH prototype. In addition, the research achievements of this project not only provide a theoretical basis for efficient MEE-HVEH, but also provide a technical support for long-term reliable self-powered WSN nodes. Therefore, this project is full of important scientific research significance and practical application value.

无线传感网络（WSN）节点的长期可靠供电问题，来源于干电池续航时间受限及电池耗尽后更换不便等困境。近年来，针对这一问题而兴起的环境振动能量收集技术研究如火如荼。本项目围绕高效磁电弹性复合振动能量收集的若干关键问题，开展了三方面研究：首先，对包含磁电弹性复合换能器与电能提取接口电路在内的整体进行系统级建模，使两者能够在同一层次进行全局优化，揭示系统内在工作机理，解决环境振动能量的高效俘获问题，提高能量转换效率；然后，通过研究基于多路负载阻抗匹配与基于反向耦合效应最优的多源电能高效提取方法、接口电路及控制策略，解决多场耦合作用下的多源电能高效提取问题，从而提高系统输出功率；最后，通过原型样机的系统级性能测试，对所提的理论方法与关键技术进行验证。项目研究成果可为高效磁电弹性复合振动能量收集提供理论依据，并为实现WSN节点长期可靠自主供电提供技术支撑，因此具有重要的科学研究意义与实际应用价值。

环境振动能量收集技术有望解决低功耗微电子设备的长期自主供电问题，已经引起了学术界与工业界的广泛关注。针对以往单一机电换能存在的转换效率低、工作频带窄、最优负载范围小等问题，本项目围绕磁电弹性复合振动能量收集的前端机电换能与后端电能提取等关键问题开展了大量研究：（1）揭示了包含压电换能与磁电换能在内的复杂力-电-磁多物理场耦合系统的内在机理，建立了“结构-电路”系统级理论模型，为系统全局优化提供了理论依据；（2）提出了一种基于复合换能的多方向升频振动能量收集器，采用频率提升方法将低频环境振动转换为结构高频振动，实现了从人体低频运动过程中收集能量；（3）提出了一种基于可动质量块的结构共振频率自调谐技术，通过检测压电开路电压与短路电流间的相位差来识别结构共振状态，实现结构共振频率与环境激励频率的自适应匹配，提高了振动能量收集器的环境适应性；（4）提出了两种基于同步开关电感电路与同步电荷提取电路的自供电混合电能提取接口电路，实现了电路峰值输出功率与负载电压范围之间的平衡；同时，提出了更加合理的性能评价指标，可用于比较不同体积尺寸的能量收集系统；（5）提出了两种分别基于“1/2开路电压法”与“分数阶工作电压法”的振动能量收集最大功率点跟踪技术（MPPT），其中后者无需断开换能器测量开路电压，仅通过测量其正常工作电压即可调节整流电压至最优值，保证了连续的能量收集过程。本项目研究成果为高效环境振动能量收集提供了理论与技术支撑，也为本领域的其它后续研究提供了新思路。