A Dynamic Control Strategy for Enhancing the Energy Extracting Capability of Magnetic Field Energy Harvesters in Sensor Nodes of Power Equipment

With the widespread application of sensors nodes in power equipment, providing a stable energy supply for these sensors has become a significant challenge. Traditional batterypowered solutions are costly and difficult to install. The development of energy harvesting technology offers a new technical approach to address this challenge. This paper mainly investigates how to enhance the energy harvesting power of Magnetic Field Energy Harvesters (MEH) under conditions where the magnetic field around power equipment is limited. A dynamic control method is proposed to improve the energy harvesting power of MEH. The fundamental idea of dynamic control is to precisely control the MOSFETs in the rectifier, dynamically adjusting the switching times of the energy harvesting interval to be symmetric around the peak current of the primary side, thereby significantly enhancing harvesting efficiency. This method is particularly applicable when the magnetic core enters the soft saturation region, causing the energy harvesting interval to be less than T/2. Experimental results show that under constant voltage load, dynamic control effectively adjusts the energy harvesting interval, maximizing the current extracted during this interval, thereby effectively increasing energy harvesting power. Compared to passive rectification, active rectification under dynamic control increases the energy harvesting power by 76%, and the power factor of active rectification is 1.7 times that of passive rectification. The research findings provide important theoretical support and practical significance for the application of magnetic field energy harvesting technology in sensor nodes.