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Multi-Paralleled Current Source Converters with Simple Configuration

配置简单的多并联电流源转换器

基本信息

批准号：
08650335
负责人：
ISE Toshifumi
金额：
$ 1.41万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

In order to simplify the configuration of mutli-parallel connected current source converters used for superconducting magnetic energy storage (SMES), nuclear fusion and etc., two methods such as 1) Reduction of harmonics by multi-parallel configuration using only DELTA-DELTA and DELTA-Y connection ans without using zigzab connection of transformer windings, 2) Series connected primary windings of transformers to balance the current without DC reactors, were examined. As for the converter circuit, snubber energy recoverable current source converter was chosen, and characteristics of the circuit were also carefully examined. Obtained results are summarized as below.1. Current balancing method by series connected primary side windings was examined by digital simulation. Current balancing was performed in the operation without short-through mode in which series connected positive and negative side devices are simultaneously turned on. Operation with such short-through mode prevents current … More of bridges from balancing, in which current does not flow through transformer windings.2. N harmonics can be canceled by the N-th power of 2 sets of converters without using transformers. For example, either 11th or 13th harmonic current can be canceled by two sets of converters in which current phases are shifted each other to cancel the harmonics, both 11th and 13th harmonic current can be canceled by four sets of converters. By using transformers with DELTA-DELTA and DELTA-Y connection, 5th and 7th harmonics are also canceled.3. Snubber capacitors are charged, even if the switching devices beside the capacitor is keeping off-state. This phenomenon is due to the effect of switching of other devices and often occurs when the capacitance value is larger. If such phenomenon occurs frequently, applied voltage to switching devices can not be decreased corresponding to increase of the capacitance value of snubber capacitors, and harmonics of ac line are increased due to the charging current.4. As for application of sinusoidal Pulse Width Modulation (PWM) control to the snubber energy recoverable current source conveter, snubber capacitor should be designed as small as possible to suppress the rate of rise of voltage across switching devices within the allowed value. Additional capacitors to ac line are required to suppress the voltage across switching devices and absorb high frequency ripple current produced by PWM. Less

为了简化超导储能、核聚变等多并联电流型变流器的结构，研究了两种方法：1)只采用Delta-Delta和Delta-Y并联结构，而不使用变压器绕组的锯齿形连接；2)在不使用直流电抗器的情况下，串联变压器一次绕组以平衡电流。在变流电路方面，选用了缓冲能量可回收电流型变流器，并对电路的特性进行了详细的分析。所获得的结果总结如下1.对一次侧绕组串联均流方法进行了数字仿真研究。在没有短通模式的操作中执行电流平衡，在该模式下串联连接的正负侧器件同时打开。在这种短路模式下运行可防止电流…更多的桥从平衡，其中的电流不流经变压器绕组。在不使用变压器的情况下，可以用2套变流器的N次方来消除N次谐波。例如，两套电流相移的变流器可以消除第11次和第13次谐波电流，四台变流器可以同时消除第11次和第13次谐波电流。通过使用Delta-Delta和Delta-Y连接的变压器，还可以消除5次和7次谐波。缓冲电容器是充电的，即使电容器旁边的开关装置处于关断状态。这种现象是由于其他器件的开关效应造成的，并且经常在电容值较大时发生。如果频繁出现这种现象，施加到开关器件的电压不会随着吸收电容器电容值的增加而降低，而交流线路的谐波会因充电电流的增加而增加。对于正弦脉宽调制(PWM)控制在缓冲能量回收电流型变流器中的应用，缓冲电容的设计应尽可能小，以将开关器件两端的电压上升率抑制在允许的范围内。交流线路需要额外的电容器来抑制开关器件两端的电压并吸收由脉宽调制产生的高频纹波电流。较少