基于虚拟同步电动机技术的变频器控制策略研究

A Novel Frequency-converter Control Strategy Based on Virtual Synchronous Motors

电力系统的一次调频是维护电网稳定运行的有效手段,变频器在日常生产和生活中占有大量比重,为了使其能够对电力系统一次调频过程产生有益的影响,该文提出一种基于虚拟同步电动机(virtual synchronous motor,VSM)技术的变频器控制策略。变频器由整流和逆变两部分主要功能组成:针对整流部分,采用Udc-Q控制策略,控制变频器向电网输出的无功及抑制向电网输出的谐波;针对逆变部分,采用虚拟同步电动机控制策略,分别设计功频控制器和无功/电压控制器,能够随所带负荷的有功和无功变化,使变频器改变输出频率和内部励磁电压,同时能够随系统频率变化调整自身功率输出。在Matlab/Simulink下对该控制策略进行仿真,仿真结果表明,所提控制策略能够使变频器模拟虚拟同步电动机的特性,可有效提高系统电能质量和系统运行稳定性。

Primary frequency regulation is effective means to protect the stability of power system. Frequency converter occupies a large proportion in production and daily life, in order to produce beneficial effects to the primary frequency regulation of the power system, a control strategy based on the technology of virtual synchronous motor （VSM） was proposed. The rectifier and the inverter are two main parts of the frequency converter. For the rectifier part, Udc-Q control strategy was utilized, it can control the converter＇s reactive power output to power grid, and effectively decrease the converter＇s harmonics output to power grid. For the inverter part, VSM control strategy was used, it concluded power-frequency controller and excitation controller, and it could change the inverter＇s output voltage and frequency with the change of motor load, and could adjust the inverter＇s output active power with the change of system frequency. The frequency converter control strategy based on VSM was simulated by using Simulink/Matlab. The simulation results show that the proposed control strategy can follow the mechanical inertia and electrical characteristics of the synchronous motor, and can effectively improve system power quality and system stability.