【目的】在双碳目标提出以来新能源迅速发展,逆变器在电力系统中的应用越来越广泛。滞环电流控制具有响应速度快、控制简单等优点,目前已被广泛用于逆变器控制当中,但传统滞环电流控制对参考电压矢量扇区准确度要求高,在扇区切换时容易出现扇区判断失误而导致误差电流失控的现象。为此提出一种基于固定开关状态切换的滞环电流控制策略。【方法】三电平滞环电流控制方法中扇区划分有多种方法,通过将三电平逆变器滞环控制中的多种扇区划分方式进行结合,有效避免了传统滞环控制在扇区边界既要更新扇区又要更新控制策略的缺点,允许参考电压矢量扇区判断存在误差的同时保证误差电流在整个周期内受控。定环宽控制下开关频率不定,开关损耗增大,因此对该策略下的定频控制策略进行研究,通过获取上一个周期的误差电流数据,更新当前周期的环宽以实现定频化,并给出了下一个周期滞环宽度的计算式。【结果】最后通过Matlab/Simulink进行仿真验证,仿真结果表明采用本文所提方法,在参考电压矢量处于扇区切换的边界时,依然能够保证误差电流在整个周期中的受控,开关频率也能够保持在20 kHz左右。【结论】本文所提的基于固定开关状态切换的定频滞环电流控制策略符合理论结果,具有准确性。

[Objective] Since the introduction of the dual carbon goals, the rapid development of renewable energy has led to an increasing application of inverters in power systems. Hysteresis current control offers advantages such as fast response and simple control, and it has been widely used in inverter control. However, traditional hysteresis current control requires high accuracy of the reference voltage vector sector, and sector switching can easily lead to uncontrollable error currents due to sector misjudgment. To address this, a hysteresis current control strategy based on fixed switch state switching is proposed. [Methods] In the three-level hysteresis current control method, there are various ways to divide the sectors. By combining different sector division methods in the hysteresis control of three-level inverters, the disadvantage of traditional hysteresis control, where both the sector and the control strategy should be updated at sector boundaries, was effectively avoided. This method allowed for errors in sector judgement of the reference voltage vector while ensuring the error current was controlled throughout the entire cycle. With a fixed loop width, the switching frequency was variable, leading to increased switching losses. Therefore, a frequency-fixed control strategy was studied under this approach. By obtaining the error current data from the previous cycle, the hysteresis width for the current cycle was updated to achieve fixed frequency control, and the calculation formula for the next cycle’s hysteresis width was provided. [Results] The method was validated through Matlab/Simulink simulations. The simulation results showed that the proposed method ensured the error current was controlled throughout the entire cycle, even when the reference voltage vector was at the boundaries of sector switching, and the switching frequency remained around 20 kHz. [Conclusion] The proposed frequency-fixed hysteresis current control strategy based on fixed switch state switching aligns well with the theoretical results and demonstrats accuracy.