等效三电平并联逆变器优化电流谐波控制

Optimal Current Harmonic Control of Equivalent Three-level Parallel Inverter

在工业电机驱动中,直接转矩控制算法有着广泛的应用。为了增大输出功率,会将多台逆变器进行并联连接。然而,传统控制算法总是将两台逆变器同步控制,没有充分利用并联变换器的优势。为了提升并联逆变器的控制效果,首先,这里将两台两电平逆变器视作一个整体,将其等效成一台三电平逆变器。接着,根据等效逆变器的电压矢量分布设计了多阶非对称转矩滞环比较器,从而提高转矩的控制精度。然后,在优化的开关表中同时包括了对转矩、磁链和零序环流的调节,实现了优秀的动态性能和稳态性能。最后,实验结果验证了所提算法的有效性。

Direct torque control is widely used in industrial motor drive applications.To increase the power output ability,multiple inverters can be connected in parallel.However,these parallel inverters are controlled synchronized in the conventional method,and the potentials of parallel inverters are not fully utilized.In order to improve the control performance,these two two-level inverters are regarded as a single three-level inverter.Then,the multi-level asymmetric hysteresis comparator is designed to enhance the accuracy of torque regulation.After that,an improved switching table is constructed,where the regulation of torque,stator flux and zero sequence circulating current are included.In the end,the experimental results verify the effectiveness of the proposed method.