【作者】 任毅；

【导师】 孙力；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2011， 硕士

【摘要】 能源危机的日益加深,环境问题的积重难返,人类正背着这两座大山踽踽前行。对于新能源的开发利用已经在各国间达成共识。作为新能源技术中的主力军,风力发电技术近些年来得到了飞速发展。本文着眼于针对解决远离电网地区电力短缺问题的非并网型永磁直驱式风力发电系统,主要从低速永磁同步发电机本体及功率变换策略方面进行研究。首先,深入分析永磁直驱式风力发电机技术特点。将低速多级结构设计、反电动势波形质量提高、固有电压调整率降低、短路电流倍数控制等方面作为电机本体设计及参数校验的重要因素。基于有限元分析的方法,合理选择定转子外形尺寸参数、槽数极数配合;设计不等厚型磁钢,进一步提高反电动势波形质量;进而,通过传统方式降低固有电压调整率,优化电机性能;对绕组短路时最大去磁工作点进行校核,验证优化后方案在短路电流倍数方面满足要求。其次,在分析风机空气动力学模型的基础上,本文对传统的最大功率跟踪(MPPT)方式进行了改进。提出了改进功率信号反馈与查表法相结合的方法,将直流侧功率近似风机输出功率,对相应风速进行区间划分,在构建的最优工作点曲线及一定风速下转速功率曲线表格的基础上,系统按不定长步长的方式快速搜索到当前风速下最佳工作点。再次,对于发电机侧功率变换器进行设计。本文将PWM整流技术应用到风力发电系统中,实现AC-DC变换、最大功率跟踪、蓄电池充电等。提出一种转速电流双闭环结构,将最大功率跟踪算法搜索到的最优转速值作为转速给定,构成系统外环,实现最大功率跟踪;采用id = 0控制方式的电流内环实现系统高功率因数运行。软件仿真及风场实验均验证该方式切实可行,且性能良好。最后,本文应用单周期控制方式对用户侧逆变器进行设计。单周期控制策略单相逆变电源能够抑制直流电压波动及负载变化对输出的影响。在对原理进行详尽分析的基础上,搭建仿真与实验平台,结果证明单周期控制输出谐波含量低、正弦度好,能够很好的满足风力发电的需要。更多还原

【Abstract】 With the burden of serious energy crisis and deteriorated environmental problem, the society of human beings is facing a horrible dilemma. To develop and utilize the new energy has been recognized among different countries. Therefore, the wind power technology has been developing rapidly in recent years. This paper focus on the non-grid-connected direct drive PMSG wind power system that aiming at changing the situation of the remote area lack of power, the low-speed generator and control strategy of converters are researched in this paper.Firstly, on the basis of comprehensive elaboration of the features about the PMSG used in wind power system. The design of low-speed multipole PMSG, inprovement of the waveform quality of back-EMF, reduction of the voltage regulation rate and control of short-circuit current are regarded as the key factors in the design and check of generator. Based on the finite element analysis, reasonable parameters and slot-pole match are chosen due to those factors. Then, a type of nonuniform thickness tile shape is designed to optimize the quality of back-EMF. The voltage regulation rate is reduced by conventional means and demagnetising working point is checked to confirm the short-circuit current proper. Through these measures, the performance of PMSG is promoted.Secondly, based on the analysis of Aerodynamics model of wind turbine, conventional MPPT strategy is discussed and improved in this paper. An improved method based on the combination of table lookup and power signal feedback is proposed. Through this new way, the power of DC link is regarded as the output power of wind turbine, the wind velocity is devided into several regions and the tables about optimal power curve and RPM-Power curve are formed in this method, the optimal working point is found out by the pattern of undifined length.Thirdly, the rectifier of the generator side is designed and researched.To realize the convert of power from AC to DC, MPPT, charging for the battery, the rectifier based on the PWM strategy is introduced to the wind power system. Two closed loop is constituted by RPM(obtained through MPPT strategy) and current. The proposed strategy is proved correct and effective through simulation and wind field experiment.Finally, the inverter for the users is analysised and designed. The OCC(one cycle control) is imported into single phase inverter in this paper. Based on the detailed analysis about the principle, simulation and experiment platforms are built, the output voltage has a good performance and lower THD. The inverter controlled by OCC strategy is fit for wind power technology, revealed by the simulation and experiment results.更多还原