Development of Multi-Level Inverter using PAM and PWM for High Voltage and Capacity Motor Drives

在这项研究中，我们的工作目的是提出并开发一种新的适用于大功率应用的五电平双变流器，与三电平变流器相比，五电平变流器具有更好的性能。但是五电平变流器存在一定的问题，如分压点电位不平衡等，需要对每个电容电压进行维护。为此，我们提出了一种基于多带滞环比较器的控制方法，用于5电平整流器作为5电平逆变器的直流电源。该方法能够保持输出直流侧电容电压，使输入功率因数保持在接近1的水平，并能向电力系统再生电能。提出了一种由五电平整流到五电平逆变器构成的五电平双变流器系统的控制策略。所提出的方法具有输出功率反馈到整流侧的系统。该系统可以直接计算整流器输出的功率。该方法实现了更多的正弦波形，且m…此外，我们还提出并开发了一种新型的1.5kVdc通勤列车的辅助电源(APS)系统，该系统采用1.2千伏的通用IGBT串联作为开关器件，取代了3千伏以上的高压IGBT。由于IGBT的低开关损耗，APS实现了5 kHz的载频。串联IGBT之间的电压平衡是通过使用简单的双绕组变压器磁耦合所有栅极线来实现的，而不需要缓冲电路。为了确保这种高载波频率对APS性能的影响，利用单相逆变器对负载突变时的滤波器噪声水平和输出电压稳定性进行了评估，并与传统载波频率的结果进行了比较。在1.2KVIGBT串联技术的基础上，设计并制造了一台实际使用的APS系统样机，并在额定技术指标下对其性能进行了评估。结果表明，与传统的高压IGBT相比，APS系统具有体积更小、声级更低的特点。与通用IGBT串联的技术有望在未来各种采用高压IGBT的中压逆变器以及APS系统中发挥重要作用。我们在IEEE IAS年会、IEEE电力电子专家会议上介绍了这项研究的一些成果，并发表了IEEJ工业应用学报和IEEJ电气电子工程学报。较少

In this research, the purpose of our work is to propose and develop a new 5-level double converter for high power applications.A 5-level converter has better performance compared to a 3-level one. But 5-level converters have certain problem such as unbalance of potentials of dividing voltage point, so we need to maintain each capacitor voltage. Hence, we proposed a control method using multi-band hysteresis comparators(MHCs) for a 5-level rectifier used as a DC power source for 5-level inverter. The method is able to maintain the output DC-link capacitor voltage, keep the input power factor a near unity, and regenerate electric power beck to the power system. This paper proposed a control strategy for a 5-level double converter system constructed by 5-level rectifier to 5-level inverter. Proposed method has a system that feedback output power to rectifier side. This system can calculate power that a rectifier output directly. The proposed method realizes more sinusoidal waveform, and m … More ore balanced each capacitor voltage.We also presented and developed a novel auxiliary power supply(APS) system for the commuter trains with 1.5kVdc employing series-connected 1.2-kV general purpose IGBTs as a switching device substituted for high-voltage IGBTs over 3kV. The carrier frequency of 5kHz in the APS is realized due to considerable low switching loss of the IGBTs. Voltage balance across the series connected IGBTs are achieved by magnetically coupling all the gate lines using a simple two-winding transformer without snubber circuits. To ensure that such the high carrier frequency is effective on APS performance, sound level from filter and output voltage stability with a sudden changed load are evaluated using a single-phase inverter, and then compared with that of a conventional carrier frequency. On the basis of the series connection technique with the 1.2kV IGBTs, a prototype of the APS system is designed and built for the actual uses, and then its performance is evaluated at its rating specifications. From the results, it is confirmed that the APS system features smaller volume and lower sound level rather than conventional ones with the high-voltage IGBTs.The series connection technique with the general-purpose IGBTs is expected to play a useful role in all sorts of the medium voltage inverters originally employing the high-voltage IGBTs, as well as the APS system, in the future.We presented some results of this research at the IEEE IAS Annual Conference, the IEEE Power Electronics Specialist Conference, and also published the IEEJ Transactions on Industry Applications and the IEEJ Transactions on Electrical and Electronics Engineering. Less