可寄生式双极电感绝对角度传感器研究

Research on Parasitic Bipolar Inductance Absolute Angle Sensor

角度传感器作为电机的核心定位部件,对电机的定位精度有重要影响。该文设计了一种双极电感式绝对角度传感器,该传感器通过周期性改变线圈中感应电压的大小来测量角度,敏感结构主要包括转子和定子,可实现与电机主轴的一体化。其中转子由内外单周期、多周期扇形铜箔组成,形成双极布局,定子由激励线圈、接收线圈以及后续处理电路组成。定子中的两组接收线圈,一组线圈由8个回路组成,对应为外沿多周期扇形铜箔,另一组由2个回路组成,对应中心180°扇形(半圆形)铜箔,两组线圈相互独立,互不影响。当转子在接收线圈上方转动时,转子中产生的涡流会使相邻两个接收线圈感应电压呈周期性正余弦形式变化。8回路线圈测量精度高,但360°内会出现多个周期信号,无法实现绝对位置测量。而2回路线圈在360°范围感应出1个周期信号,通过2回路线圈为8回路线圈提供周期数鉴别,进而解决了绝对位置测量的问题。通过算法对正余弦信号进行识别解算,以高精度转台为基准对样机进行测试,结果表明,传感器测量误差可以达到0.04°,满足电机位置控制精度要求,验证了该方案的可行性。

As the core positioning component of the motor,the angle sensor has an important impact on the positioning accuracy of the motor.In this paper,a bipolar inductive absolute angle sensor is designed.The sensor measures the angle by periodically changing the induced voltage in the coil.The sensitive structure mainly includes the rotor and stator,the integration with the motor spindle can be realized.The rotor is composed of inner and outer single cycle and multi cycle fan-shaped copper foil in a bipolar layout,and the stator is composed of excitation coil,receiving coil and subsequent processing circuit.There are two groups of receiving coils in the stator.One group of coils is composed of 8 loops,corresponding to multi cycle sector copper foil on the outer edge,and the other group is composed of 2 loops,corresponding to 180°sector(semicircular)copper foil on the center.The two groups of coils are independent of each other and do not affect each other.When the rotor rotates above the receiving coil,the eddy current generated in the rotor will make the induced voltage of two adjacent receiving coils change in the form of periodic sine and cosine.The measurement accuracy of 8-loop coil is high,but multiple periodic signals will appear within 360°,so the absolute position measurement cannot be realized.By measuring the number of cycles of the coil,the problem is solved by identifying the number of cycles of the coil 1 and the number of cycles of the coil 2.The sine and cosine signals are identified and solved by the algorithm,and the prototype is tested based on the highprecision turntable.The results show that the measurement error of the sensor can reach 0.04°,which meets the requirements of motor position control accuracy,and verifies the feasibility of the scheme.