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

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.