摘要
永磁同步电机在工业现场应用广泛。为分析基于变频器实现软启动的永磁同步电机在电压暂降场景下的动态运行特性,提出一种永磁同步电机低电压穿越能力评估方法。首先,基于dq坐标系建立电磁转矩与功角、端电压间的解析式,分析暂态过程中的转差率与电机稳定性之间的关系,建立基于转差率的电机暂态稳定分析判据,进而确定电机安全稳定临界电压;其次,基于面积法则推导临界切除功角解析式,得到故障临界切除时间;最后,选择安全稳定临界电压和故障临界切除时间为电机低电压穿越能力的特征值。研究表明,暂态过程中转差率是否存在负值可作为暂态能否稳定的判据,电机带载率越小其低电压穿越能力越强。
Permanent magnet synchronous motor is widely used in industrial sites.In some cases,it is started softly by variable frequency converter and then switched to operate normally with power frequency.In order to analyze such motor operating characteristic with voltage sag,a method for evaluating the low voltage ride through capability of permanent magnet synchronous motors is presented in this article.Based on the dq coordinate system,the analytical formula among electromagnetic torque,power angle and terminal voltage is established.With the relationship between slip and motor stability in the transient process,the slip based motor transient stability analysis criterion is established.It can be used to determine the safety and stability critical voltage of the permanent magnet synchronous motor.The analytical formula of critical cutting power angle is deduced by area law.Then,the critical cut-off time of fault can be got.Critical voltage and fault removal time is selected as the characteristic value to evaluate the motor's low voltage ride through capability.The transient stability can be judged by the negative slip value in the transient process.The smaller the motor load rate,the stronger the low voltage ride through capability.Simulation results verify the effectiveness of the evaluation method.
作者
仉志华
董浩东
张昊
李炜
孙泽岳
ZHANG Zhihua;DONG Haodong;ZHANG Hao;LI Wei;SUN Zeyue(College of New Energy,China University of Petroleum(East China),Qingdao 266580,China;SINOPEC Shengli Oilfield Company,Dongying 257002,China;School of Electrical and Communications,University of New South Wales,Sydney 2052,Australia)
出处
《电力工程技术》
北大核心
2022年第5期202-209,共8页
Electric Power Engineering Technology
基金
国家自然科学基金资助项目(51977220)
山东省自然科学基金资助项目(ZR2019MEE057)。
关键词
电压暂降
永磁同步电机
暂态稳定性
临界稳定电压
临界切除时间
低电压穿越
voltage sag
permanent magnet synchronous motor
transient stability
critical stable voltage
critical resection time
low voltage ride through
