微型扬声器线圈温度测量系统设计

The Design of Coil Temperature Measurement System for Micro Loudspeaker

为实现对微型扬声器线圈温度的实时监控,设计了一套线圈温度测量系统。使用Audacity软件在测试音频中叠加50Hz低频信号,使用STM32H7的DUAL ADC模式实现扬声器电压电流值的同步采样,使用改进型Goertzel算法计算出50Hz频率对应的直流阻抗,利用直流阻抗与线圈温度的对应关系得到线圈温度;将扬声器置于温箱中作为温度传感器,对比温箱设定温度及扬声器计算所得温度。结果显示两者基本一致,相对偏差不超过2%,绝对偏差不超过2℃,说明所提出的测量系统能有效实现扬声器线圈温度的实时监控。

In order to realize the real-time monitoring of the coil temperature of micro loudspeaker,a coil temperature measurement system was designed.Audacity software was used to stack 50Hz low frequency signal in test audio,and dual ADC mode of stm32h7 was applied to realize synchronous sampling of loudspeaker voltage and current value.Improved Goertzel algorithm was utilized to calculate DC impedance corresponding to 50Hz frequency.By means of the corresponding relationship between DC impedance and coil temperature,coil temperature was tested.The loudspeaker was placed in the temperature box as temperature sensor to compare the set temperature of the temperature box and the calculated temperature of loudspeaker.The results show that the two are basically the same,the relative deviation is less than 2%,the absolute deviation is less than 2 degrees,which shows that the proposed measurement system can effectively realize the real-time monitoring of speaker coil temperature.