旋变幅值误差和正交误差在角速度频谱上表现为旋变转频的二次谐波，是旋变测角误差的主要来源，影响伺服系统角速度控制精度和稳定度。本文提出了一种基于特征频率参考的二次谐波误差自校正方法。首先，分析旋变测角误差产生的机理，获知其幅值误差和正交误差的互不相关性，并证明对旋变输出信号进行幅值调整和相位差调整可实现二次谐波误差校正。然后，在旋变和旋变数字信号转换器（Resolver-to-Digital Converter，RDC）之间设计基于比例放大的幅值校正器和基于交叉调节的相角校正器。最后，根据误差信号在线性控制系统中特征频率不变的特性，对伺服系统进行匀速控制，以角速度频谱中二次谐波频率的幅值为参考基准，分别调整幅值校正器和相角校正器，校正二次谐波误差。实验结果表明：本方法可将旋变二次谐波测角误差幅值降低78.5%，伺服系统速率波动量降低40.5%。本方法实现了旋变二次谐波测角误差的自校正，大幅提升了旋变的测角精度和伺服系统的转速控制稳定度。

The resolver amplitude error and quadrature error are expressed in the angular velocity spectrum as the second harmonic of the rotational frequency， which is the main source of the resolver angle measurement error and affects the angular velocity control accuracy and stability of the servo system. In this paper， a self-correction method for the second harmonic error of resolver based on characteristic frequency reference was proposed. Firstly， the mechanism of the resolver error was analyzed， and the mutual irrelevance of the amplitude error and quadrature error was obtained， and it was proved that the second harmonic error correction could be realized by adjusting the amplitude and phase difference of the resolver output signal. Then， the amplitude corrector based on proportional amplification and the phase angle corrector based on cross-adjustment were designed between the resolver and the Resolver-to-Digital Converter （RDC）. Finally， according to the constant characteristic frequency of the error signal in the linear control system， the servo system was controlled at a constant speed， and the amplitude of the second harmonic frequency in the angular velocity spectrum was used as the reference to adjust the amplitude corrector and phase corrector respectively， to correct second harmonic errors. The experimental results show that the method can reduce the second harmonic angle measurement error of the resolver by 78.5%， and the speed fluctuation of the servo system can be reduced by 40.5%.The method realizes the self-correction of the second harmonic error of the resolver， and can greatly improve the measurement accuracy of the resolver and the rotation stability of the servo system.