基于误差电压精确计算的表贴式永磁同步电机逆变器非线性补偿方法

Inverter Nonlinearity Compensation Method for SPMSM Drives Based on Accurate Voltage Error Calculation

根据电流反馈确定误差电压的逆变器非线性补偿被广泛用于永磁同步电机驱动系统,其整定过程得到的误差电压包含两相逆变器非线性因素。为获得各相误差电压,传统方法假设不同电流下任意相误差电压数值相等,然而该假设在小电流时并不成立,导致补偿效果欠佳。为此,该文提出一种基于迭代线性插值的误差电压精确计算方法,综合考虑死区时间、功率器件开通/关断延时、寄生电容和开关管压降等多种非线性因素影响,得到相误差电压与相电流幅值的准确映射关系。针对由零电流钳位导致的电流过零附近误差电压判断不准问题,提出基于相电流指令的误差电压判断方法,进一步提升补偿效果。实验结果表明,与现有逆变器非线性补偿方法比较,所提方案具有更优的暂、稳态补偿效果和电流谐波抑制能力。

Voltage source inverter(VSI) nonlinearity compensation that uses current feedback information to determine voltage error(known as the look-up table method)has been widely used in permanent magnet synchronous motor drive system. The nonlinearity factors obtained during the commissioning process contain voltage errors(VEs) from two phases. In order to obtain the VE of each inverter phase, the traditional method assumes that the values of VE at different current amplitudes are equal. However, such an assumption cannot stand when the VSI is operating under small current,and the compensation performance deteriorates. Aimed at this issue, this paper proposed an accurate VE calculation method based on iterative linear interpolation. The nonlinear effects,such as dead-time, turn-on and turn-off delay, parasitic capacitance and voltage losses on the power devices were comprehensively considered by the proposed method. Accurate mapping between the VEs of each inverter phase and their corresponding phase current amplitudes was obtained.Moreover, in order to solve inaccurate judgement of the VE caused by the zero-current clamping effect, the phase current references were used for determining the VE.Experimental results show that compared with the existing VSI nonlinearity compensation methods, the proposed method in this paper can achieve better compensation performance and current harmonic suppression ability under both dynamic and steady states.