In this paper, we originally investigate how formulation of abrupt magnetic flux density change influences the electric outputs, e.g. open-circuit voltage, power density and charging rates, of electromagnetic energy harvesters. Electromagnetic energy harvesters are comprised of one magnet array and two sets of coil arrays. In a certain volume, the dimension and number of magnets evidently determines the number of abrupt magnetic flux density change (denoted as β, β=0,1,2,3,5,7) and further the output voltage. To study how this correlation affects the performance of the harvester, a configuration is first proposed and by conducting simulation, we infer that the highest voltage is induced by the case where β=3, namely when the length, height and width of the magnet are the same. This hypothesis is further validated by three series of experimental results: the open-circuit voltage first increases, reaches its peak where β=3, and falls off sharply as β increases from 0 to 7; the cubic-magnet array configuration yields the highest power and power density, more than 20 times higher than that of the case without abrupt magnetic flux density change. The instantaneous power reaches as high as 284 mW under resonance at 1 g excitation acceleration with an overall dimension of 4.8cm × 3.9cm × 2.5cm; The charging-capacitor experimental results confirms this as the cubic magnet case yields the largest charging rate and highest saturation voltage. We mainly attribute this phenomenon to the collective relation of the flux change and magnet volume as β grows from 0 to 7. This finding reveals the best configuration of magnet arrays that leads to the most desirable performance from electromagnetic energy harvesters.

在本文中，我们最初研究突然的磁通密度变化的公式如何影响电磁能量采集器的电输出，例如开路电压，功率密度和充电率。电磁能量收集器由一个磁体阵列和两组线圈阵列组成。在一定的体积内，磁体的尺寸和数量显然决定了突然的磁通密度变化的数量（表示为β，β= 0、1、2、3、5、7），进而决定了输出电压。为了研究这种相关性如何影响收割机的性能，首先提出了一种配置，并通过进行仿真，我们推断出最高电压是由β=如图3所示，即当磁体的长度，高度和宽度相同时。通过三个系列的实验结果进一步验证了这一假设：开路电压首先增加，在β= 3时达到峰值，然后随着β急剧下降。从0增加到7；立方磁体阵列结构可产生最高的功率和功率密度，比不发生突然的磁通密度变化的情况高出20倍以上。共振功率为1 g激发加速度时，瞬时功率高达284 mW，外形尺寸为4.8cm×3.9cm×2.5cm。充电电容器的实验结果证实了这一点，因为立方磁体外壳可产生最大的充电速率和最高的饱和电压。我们主要将此现象归因于随着β从0增长到7 ，磁通量变化和磁体体积的集体关系。这一发现揭示了磁体阵列的最佳配置，从而导致了电磁能量采集器的最理想性能。