可寄生式双极电感绝对角度传感器研究

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 includes mainly 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 can not 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 high-precision 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.