摘要：为了能够有效地解决电动车窗存在的安全隐患问题，现在有许多汽车都采用了电动车窗防夹系统。实现电动车窗的防夹功能就需要考虑两个核心的问题：车窗位置的确定和车窗状态的检测。所以要求在设计电动车窗防夹的时候，必须要连续的监测电机的电流，车窗的精确位置，判断车窗是否进入防夹区域，是否遇到障碍物，以决定是否需要对车窗实施防夹功能。
本文设计的是一种基于电流纹波检测的车窗防夹控系统。电动机在运行的时候，就会有交流电流叠加在直流电流上，从而产生纹波。电机每旋转一周，就会产生固定数量N的电流纹波，车窗运动的行程与电机的电流纹波数量成线性关系。这样，采用检测电流纹波数量来计算出车窗的运动行程，从而确定车窗位置，如果车窗位置处于防夹区域内，便利用功率驱动器BTS7960的电流检测功能对电机电流采样，得到电机电流的实时值，再与标准电机电流值进行比较。若差值大于允许的差值，则认为是遇到障碍物，进入防夹状态，控制车窗回落；反之，如果车窗位置不在防夹区域内，则不进入防夹状态。
这种方法不需要霍尔传感器，成本较霍尔传感器方案低，对配置的电机要求低，简化了硬件电路设计，电机安装简单、方便，且可靠性高，具有良好的防夹功能。
关键词：电动车窗 防夹 电流纹波
ABSTRACT：In order to effectively solve the power window safety problems exist, there are many cars have adopted anti-pinch electric windows system.To achieve power windows pinch function you need to consider two core issues: determine the location of windows and window state is detected.Therefore, anti-pinch electric windows in the design requirements, it must be continuous monitoring of the motor current, the precise location of the window, to determine whether to enter the anti-pinch window area is an obstacle to determine whether the need for the implementation of the window pinch function.
This design is based on current ripple detection window anti-pinch control systems.When the motor is running, there will be alternating current superimposed on the DC current, the resulting ripple.Per motor revolution, it will generate a fixed number N of current ripple, window motor sport trip with a linear relationship between the number of current ripple.Thus, with the number of detected current ripple to calculate the movement of the window itinerary to determine the window position if the window position is pinch region, took advantage of the power drive BTS7960 the motor current detection current sample, get the motor current the real value, and then with the standard motor current value, if the difference is greater than the allowed difference is considered to be an obstacle to enter the pinch status, control windows down.Conversely, if the position is not anti-trap windows within the region, not to enter the pinch state.
This method does not require Hall sensor, low-cost solution compared to Hall sensors, the configuration of the motor requirements low, simplifying the hardware circuit design, electrical installation is simple, convenient, and highly reliable, with good anti-pinch function.
Keywords: power window；pinch protection；current ripple
本设计主要是系统通过检测车窗位置和车窗电机电流，在电动车窗上升过程并进入防夹区域中夹住物体并达到一定力度后，让电动车窗自动停止或回落，用以防止物体(尤其是人体)被夹伤。完成防夹力、防夹区域的设定，防夹力的检测，车窗位置的检测，实现车窗的防夹动作。其主要内容包括：
① 电动车窗防夹系统的工作原理分析；
② 防夹系统硬件设计；
③ 驱动电流检测和车窗位置检测；
④ 防夹系统软件设计；
⑤ 系统调试。
