【作者】 刘健俊；

【导师】 周理兵；

【作者基本信息】 华中科技大学 ， 电机与电器， 2009， 硕士

【摘要】 永磁直驱变速恒频发电系统由于减少了变速装置,成本降低,可靠性得到提高。在风力发电及轴带发电等方面具有广阔的应用前景。系统一般由原动机、永磁发电机、电力电子变换装置组成。当原动机在较宽转速范围运行时直接驱动的永磁发电机将发出变频变幅值的交流电,经电力电子装置中的AC/DC和DC/AC变换输出恒频恒压交流电。本文针对永磁直驱变速恒频发电系统需求,研究开发一种大功率宽范围输入直流稳压变换器,与前级不控整流电路以及后级输入电压稳定逆变器构成交流恒频恒压输出变换装置。根据理论分析该变换器采用非隔离的升降压电路拓扑,通过对不同模式的切换控制,可以在减小功率器件的最大电流应力、最大电压应力条件下实现变速恒压输出的功能。当发电机工作于低转速区时,输入电压小,在额定负载功率下输入电流大。因此,该变换器在工作于升压模式时采用交错并联控制,通过减小每路电感电流达到减小装置体积,提高功率密度的要求。同时提高了纹波电流频率,降低幅值,抑制其对输出电压的影响。每个并联单元电流单独控制,避免了各并联单元不均流的状况的出现。基于TMS320LF2407芯片数字控制,研制了一台24kW直流稳压变换器样机,并进行了实验研究,实验结果表明本课题设计的该变换器达到了技术指标要求。更多还原

【Abstract】 The permanent magnet direct drive variable speed constant frequency(VSCF) systems is characterized by high reliability and low cost due to lack of variable-speed device. So it has comprehensive application in wind power generation and vehicle shaft generator field.The system makes up of prime mover, permanent generator and power electronic device. As the speed of permanent generator which is dragged by the prime mover alters in wide range, the alternating current with variable frequency and amplitude of voltage need to be converted to constant by AC/DC and DC/AC converter.Aiming at the requirement of permanent magnet direct drive VSCF systems, a design project of high power and wide input DC/DC converter is presented in this paper. The converter and the three-phase diode rectifier and the inverter by steady-going dc-link voltage constitute the power electronic device which exports constant alternating current. By changing the mode of the non-isolated buck-boost circuit, the voltage stress and current stress of power devices can reduce greatly.When the permanent magnet generator works at low-speed zone, the amplitude of input voltage is low. So the circuit uses interleaving-control when it works at Boost mode. The current of every inductance can reduce, and the whole equipment will take less space. Power density will heighten accordingly. On the other hand, this strategy raise the frequency and reduce the amplitude of current ripple in order to restrain the fluctuation of output. The current of every parallel unit is controlled alone which insures current -averaging.a prototype which has 24kW is developed on the platform of DSP TMS320LF2407 chip. The result of experiments validate that the converter which is designed in this paper achieves the goal of specifications.更多还原