【目的】针对永磁同步电机无模型预测电流控制(MFPCC)中存在的稳态控制精度不足与电流增量更新停滞问题,提出一种基于离散空间矢量调制(DSVM)的改进型MFPCC方法。【方法】首先,引入DSVM技术扩展电压矢量集合,将一个控制周期均分为3段以合成37个虚拟电压矢量,有效提升系统的稳态控制性能。其次,通过定义单位电压矢量并对电压矢量进行坐标化表征,将电流增量更新转化为单位电流增量建立,有效解决传统方法中电流增量更新停滞的问题。进一步,利用参考电流增量解析最优电压矢量的理论坐标范围,实现电压矢量预筛选,将候选矢量从37个缩减至4个,显著降低因评估所有电压矢量导致的计算负担激增问题。最后,在一台2 kW试验平台上对所提方法的可行性及有效性进行系统性的试验验证。【结果】试验结果显示,与传统MFPCC相比,所提方法在900 r/min、5 N·m负载稳态工况下的dq轴电流纹波由5.4 A和5.0 A降低到3.1 A和3.0 A,相电流总谐波失真由17.36%降低至7.43%,转矩脉动得到有效抑制;在转速由500 r/min阶跃变化至1 000 r/min动态工况下,动态调节时间为60 ms,与传统MFPCC性能相当。所提方法执行时间为29.5 μs,仅比传统MFPCC增加了1.9 μs,能支持逆变器最高30 kHz的开关频率运行。【结论】所提改进型MFPCC在保持低运算负担的同时,显著提升了MFPCC的稳态性能。

[Objective] To address the issues of poor steady-state control performance and stagnation of current increment updates in the model-free predictive current control (MFPCC) for permanent magnet synchronous motor, an improved MFPCC method based on discrete space vector modulation (DSVM) is proposed. [Methods] Firstly, DSVM technology was introduced to expand the voltage vector set. By dividing one control cycle into three equal segments to synthesize 37 virtual voltage vectors, the steady-state control performance of the system was effectively enhanced. Secondly, by defining unit voltage vectors and representing the voltage vector in a coordinate form, the current increment update was transformed into unit current increment establishment, thereby resolving the issue of current increment update stagnation in traditional methods. Furthermore, the theoretical coordinate range of the optimal voltage vector was analytically derived using the reference current increment to achieve voltage vector pre-screening, reducing the candidate vectors from 37 to 4. This significantly mitigated the sharp increase in computational burden caused by evaluating all voltage vectors. Finally, systematic experimental validation was conducted on a 2 kW experimental platform to verify the feasibility and effectiveness of the proposed method. [Results] Experimental results demonstrated that, compared with conventional MFPCC, the proposed method reduced the dq-axis current ripple from 5.4 A and 5.0 A to 3.1 A and 3.0 A under steady-state conditions at 900 r/min and 5 N·m load. The phase current total harmonic distortion was reduced from 17.36% to 7.43%, and torque ripple was effectively suppressed. Under dynamic conditions with speed stepping from 500 r/min to 1 000 r/min, the dynamic adjustment time was approximately 60 ms, which was comparable to that of traditional MFPCC. The execution time of the proposed method was 29.5 μs, only 1.9 μs longer than that of traditional MFPCC, supporting inverter switching frequencies up to 30 kHz. [Conclusion] The proposed improved MFPCC effectively enhances the steady-state performance of the MFPCC while maintaining low computational load.

国家自然科学基金(52377013)