Electromagnetic Vibration Energy Harvesting Using an Improved Halbach Array

This paper reports an electromagnetic vibration energy harvester using an improved Halbach array. A Halbach array is a specific arrangement of permanent magnets that concentrates the magnetic field on one side of the array while cancelling the field on the other side to almost zero. Previous research showed that although the Halbach array has higher magnetic field density compared to normal magnet layouts, its magnetic flux gradient is not as high. Thus, output powers of energy harvesters with Halbach arrays were found to be less than those with normal magnet layouts. This paper proposes an improved Halbach array that achieves both high magnetic field strength and magnetic flux gradient. Test results showed that the improved Halbach array can increase the output power of energy harvesters by a factor of seven compared to the previous Halbach design and by a factor of 1.5 compared to the normal configuration.