【目的】针对大功率双馈风电变流器三电平拓扑在低频工况下因半周期调制引发的功率器件结温波动与寿命衰减问题，本文提出了一种基于运行状态感知与性能优化的三电平有源中性点钳位(ANPC)/中性点钳位(NPC)切换运行控制方法。【方法】采用频率自适应的动态拓扑切换技术，高频段启用ANPC拓扑以降低开关损耗，低频段切换至NPC拓扑抑制二极管导通损耗，结合高精度仿真与实物平台验证。【结果】试验结果表明，所提控制方法在双馈三电平变流器运行过程中表现出显著优势，尤其在二极管结温波动抑制方面效果突出。根据转子频率动态匹配最优拓扑结构，变流器功率器件的损耗分布更趋合理，二极管结温在宽频率范围内的波动幅度得到有效降低。【结论】所提方法兼顾了系统控制性能与器件可靠性，为双馈三电平变流器低频控制策略设计提供了新的适用性方法。

[Objective] Aiming at the issue of power device junction temperature fluctuations and lifetime degradation caused by half-cycle modulation in high-power doubly-fed wind power converters with three-level topologies under low-frequency operating conditions, this paper proposes an operational state-aware and performance-optimized switching control method between three-level active neutral-point-clamped (ANPC) and neutral-point-clamped (NPC) modes. [Methods] A frequency-adaptive dynamic topology switching technique was employed, where the ANPC topology was activated in the high-frequency range to reduce switching losses, while a switch to the NPC topology was implemented in the low-frequency range to suppress diode conduction losses. This approach was validated through high-fidelity simulation and a physical prototype platform. [Results] Experimental results demonstrated that the proposed control method exhibited significant advantages during the operation of the doubly-fed three-level converter, with particularly outstanding effectiveness in suppressing diode junction temperature fluctuations. By dynamically matching the optimal topology to the rotor frequency, the loss distribution of the converter’s power devices was rendered more rational, and the fluctuation amplitude of the diode junction temperature was effectively reduced over a wide frequency range. [Conclusion] The proposed method effectively balances system control performance and device reliability, thus providing a viable and novel approach for the design of low-frequency control strategies in doubly-fed three-level converters.

中国科学技术部智能电网-国家科技重大专项(2024ZD0800400)