基于虚拟负电阻的航空静止变流器并联控制策略

Parallel Control Strategy for Aviation Static Converters Based on Virtual Negative Resistance

在航空微电网系统中,通常需要航空静止变流器提供稳定的电压和频率。为了提高微电网的容量,通常采用多台变流器并联运行,但并联变流器的输出阻抗以及线路阻抗的差异会导致系统功率分配不均问题。在负载不对称的情形下,微网系统的线路阻抗会增加公共点电压的不对称度,影响微网的供电质量。为解决上述问题,采用有互联线的分散逻辑控制策略对系统功率进行均分,并加入了虚拟负电阻策略,降低了当不对称负载出现时并联系统三相电压的不对称度。最后通过实验平台验证了策略的正确性。

In an aviation microgrid system, aviation static converters are required to provide stable voltage and frequency. To improve the capacity of microgrid, multiple converters are usually operated in parallel. However, due to the differences in the output impedance from parallel converters and the line impedance, the problem of disproportionate power sharing will arise in the system. In the case of unbalanced loads, the unbalance degree at the point of common coupling（PCC） will increase because of the line impedance of microgrid system, thus affecting the power supply quality of microgrid. To solve the above problems, a distributed logic control strategy is used to share the system power. In addition, virtual negative resistance strategy is introduced, which reduces the unbalance degree of three-phase voltage in the parallel system when unbalanced loads exist. Finally, experiments conducted on an experimental platform validated the proposed control strategy.