Studies on Magnetic Induction Heating Equipments to Generate Super-Steam.

研制了三种产生超高压蒸汽的高频逆变器，其工作频率分别为100、200和300 kHz。采用的电路结构为零电流开关(ZCS)下的电压馈电全桥结构，开关器件分别为静止感应晶体管(SITS)用于100和200 kHz逆变器和功率MOS FET(用于300 kHz逆变器)。逆变器的最大输入功率为6.4kW(400V/16A)。所制备的面包板工作在200V的输入电压下。产生超蒸气的负载是含有加热物质的聚四氟乙烯树脂(外径120 mm，内径100 mm，长度400 mm)制成的管子。这是由于聚四氟乙烯树脂容易加工的原因。首先，采用碳素陶瓷和磁性不锈钢作为加热材料。然而，我们的初步实验表明，碳陶瓷被发现适合作为加热物质…由于其作为热负荷的稳定性较高。碳陶瓷是一个直径90 mm、高90 mm的圆柱体。在它上面钻了14个直径为10毫米的孔，以增加它的接触面，使流体流过它。将三个碳陶瓷垂直插入特氟龙管，间隙为15 mm。已知超蒸汽在170℃以上活动，但在我们的实验中，它的最高温度被限制在260℃以下。考虑到聚四氟乙烯树脂的耐热温度为300kHZ，使用SITS的100kHz和200kHz高频逆变器可以稳定运行，尽管其波形存在一定的失真。另一方面，使用功率MOSFET的300 kHz逆变器的波形显示出很大的失真。相应地，对其电路构成和驱动电路进行了改进。在我们的实验中，将800毫升的水插入到特氟龙管中，使整个底部的碳陶瓷浸入水中。然后，将水加热到98℃。最后，继续加热，直到另外两个碳陶瓷的温度达到260℃。结果，检测到了透明的超蒸气产生。此外，根据实验结果，给出了100、200、300 kHz高频逆变器在50kW输出功率下的具体设计方法，并给出了具有辅助开关的SEPP谐振高频逆变器的工作原理和实验结果，为感应加热应用提供了参考。然而，由于其输出功率不足，它无法产生超级蒸汽。较少

Three types of high frequency inverters were prepared to generate super-steam, which operate at 100, 200 and 300 kHz, respectively. The circuit constitution adopted was the voltage-fed full bridge type operated at zero current switching operation (ZCS).Switching devices utilized were Static Induction Transistors (SITs) for the 100 and 200 kHz inverters and power MOS FET for the 300 kHz inverter, respectively. The inverters were designed at maximum input power of 6.4 kW (400V/16A). The prepared breadboards were operated at input voltage of 200 V. The load for super-steam generation was the pipe made of Teflon resin (outer diameter of 120 mm, inner diameter of 100 mm and length of 400 mm), which contained a heating substance. It came from the reason that Teflon resin was easy to process. At first, carbon ceramics and magnetic stainless steel were adopted as the heating substance. However, our preliminary experiment revealed that carbon ceramics was found suitable for the heating substanc … More e due to its stability as the heating load. The carbon ceramics was a cylinder of 90 mm in diameter and 90 mm in height. The 14 holes of 10 mm in diameter were bored in it to increase its contact surfaces with a fluid flowing through it. Three carbon ceramics were inserted into the Teflon pipe in vertical direction with 15 mm gaps. Super-steam was known active above 170 ℃, however, its maximum temperature was restricted below 260 ℃ in our experiments. It took into account the fact that the heat-resistive temperature of Teflon resin was 300 ℃.The high frequency inverters of 100 and 200 kHz using SITs could be operated stably in spite of some distortion in their waveforms. On the other hand, the inverter of 300 kHz using power MOSFETs revealed substantial distortion in its waveforms. Accordingly, its circuit constitution and driving circuits should be refined. In our experiments, water of 800 cc was inserted into the Teflon pipe so that whole of the bottom carbon ceramics was submerged in water. Then, the water was heated till 98 ℃. Finally, heating process was continued till the temperature of the other two carbon ceramics reached 260 ℃. As a result, transparent super-steam was detected to generate. In addition, simulation analysis revealed the definite design procedure for high frequency inverters of 100, 200 and 300 kHz of super-steam generation feeding output power of 50 kW on the basis of our experimental results.Moreover, operational principle and experimental results of an SEPP resonant high frequency inverter with auxiliary switches operating at high efficiency were found useful for induction heating uses. However, super-steam could not be generated by it since its output power was insufficient. Less