【目的】针对小型离网垂直轴风电系统在变风速和负载扰动下存在的机侧转矩脉动大、直流母线电压波动明显等问题,提出一种基于超螺旋滑模算法-直接转矩控制-空间矢量脉宽调制(STA-SVPWM-DTC)与DC/DC稳压的协同控制策略,同时实现时间转矩脉动的抑制与母线电压稳定调控。【方法】采用分层解耦控制思路,将系统划分为机侧整流与直流侧稳压两大模块。机侧控制以定子磁链误差与电磁转矩误差构建复合滑模面,利用超螺旋滑模控制(STSMC)输出连续平滑的控制信号,经SVPWM驱动机侧PWM整流器,从而消除传统DTC因滞环离散切换引起的高频转矩纹波。直流侧则构建电压外环串联电感电流内环的双闭环DC/DC稳压架构,通过独立稳压回路阻隔负载侧功率波动向机侧传递,削弱两侧控制通道间的反向耦合干扰。【结果】为验证所提策略的性能,设置多组仿真工况与实物负载试验进行对比测试。风速由12 m/s降至7 m/s的阶跃工况下,仿真结果表明,相较传统DTC,所提STA-SVPWM-DTC及DC/DC协同控制方法可将电磁转矩峰峰值由1.35 N·m降低至0.4~0.5 N·m,降幅达60~70%;在阶跃风速、组合风速及10 Ω带载试验条件下,直流母线电压均可稳定在12 V附近,且电压与电流纹波明显减小。【结论】所提STA-SVPWM-DTC及DC/DC协同控制策略能够改善小型离网垂直轴风电系统的转矩平滑性和直流输出稳定性,为离网风电供能系统的稳定运行提供了一种可行控制方案。

[Objective] To address the issues of large generator-side torque ripple and significant DC-bus voltage fluctuation in small off-grid vertical-axis wind turbine systems under variable wind speeds and load disturbances, a cooperative control strategy based on super-twisting algorithm direct torque control, space vector pulse width modulation (STA-SVPWM-DTC), and DC/DC voltage regulation is proposed, which simultaneously suppresses torque ripple and stabilizes the DC-bus voltage. [Methods] A hierarchical decoupling control approach was adopted, dividing the system into two main modules: generator-side rectification and DC-link voltage stabilization. For the generator-side control, a composite sliding manifold was constructed using stator flux error and electromagnetic torque error. A super-twisting sliding mode control (STSMC) was utilized to output a continuous and smooth control signal, which drove the generator-side PWM rectifier via SVPWM, thereby eliminating the high-frequency torque ripple caused by the hysteresis-based discrete switching in conventional DTC. On the DC-link side, a dual-loop DC/DC voltage regulation architecture was built with a voltage outer loop cascaded with an inductor current inner loop. An independent voltage regulation loop was used to block the transmission of load-side power fluctuations to the generator side, attenuating the reverse coupling interference between the two control channels. [Results] To verify the performance of the proposed strategy, multiple sets of simulation conditions and physical load experiments were set up for comparative testing. Under the step wind speed condition where the wind speed decreased from 12 m/s to 7 m/s, simulation results showed that, compared with the conventional DTC, the proposed STA-SVPWM-DTC and DC/DC coordinated control method reduced the peak-to-peak electromagnetic torque from 1.35 N·m to 0.4~0.5 N·m, a decrease of 60~70%. Under step wind speed, combined wind speed, and 10 Ω load experimetal conditions, the DC bus voltage was stabilized near 12 V, and the voltage and current ripples were significantly reduced. [Conclusion] The proposed STA-SVPWM-DTC and DC/DC coordinated control strategy improves the torque smoothness and DC output stability of small off-grid vertical-axis wind power systems, and provides a feasible control scheme for the stable operation of off-grid wind power supply systems.

江苏省研究生实践创新计划项目(26CXJH3167)