m-Mode SVPWM Technique for Power Converters

In traditional SVPWM, all operating modes or voltage space vectors of the inverter need participate in modulation, which results in a large amount of calculation in the digital processor and the corresponding computational complexity. It is well known that reducing the number of voltage space vectors is a potential methodology to simplify the calculation of SVPWM. Since 2001, the authors have studied the modulation characteristics of power electronic converters to solve the computational complexity problem of SVPWM. In terms of the system state controllability, it is found that not all voltage space vectors are required for the SVPWM process, when the inverter is regarded as a switched linear system. Further, some redundant voltage space vectors can be ignored to reduce the computational complexity of SVPWM and achieve the desired control output. Based on the above results, the rotating voltage space vector can be synthesized by fewer voltage space vectors, and a novel and simpler SVPWM can be obtained. In fact, any rotating voltage space vector has a variety of synthesis methods on the basis of the space vector graph of SVPWM, when the angle between two voltage space vectors forming the rotating voltage space vector is less than 180°, so it is possible to choose the modulation method having fewer voltage space vectors to realize SVPWM. The drawn conclusion of the system state controllability analysis in geometry can be confirmed. Therefore, in view of the system state controllability, the authors do propose the mechanism and criterion of m-mode SVPWM, and develop the corresponding strategies applied for two-level inverters, dual-output inverters, multiphase inverters, three-level inverters, modular multilevel inverters, and PWM rectifiers. Theoretical and experimental results validate that m-mode SVPWM has simpler calculation, lower switching frequency, and higher efficiency than the existing SVPWM. The m-mode SVPWM, we concluded, is an innovative one. This book consists of four parts. According to the switched linear system theory, the first part reveals the state controllability of power electronic converters and puts forward the corresponding m-mode state controllability criteria and the m-mode SVPWM mechanism. Based on the above theory, the m-mode SVPWM strategies of the three-phase four-wire inverter, nine-switch dual-output inverter, five-leg v dual-output inverter, and three-phase three-level inverter are proposed in the second part in detail, and the proposed SVPWMs are compared with the traditional ones to verify their superiorities. By reducing the number of inverter operating modes, the following part exhibits the application of m-mode state controllability to the complex modular multilevel inverter to simplify the PWM strategy. The m-mode SVPWM mechanism, in the last part, is popularized and applied to the PWM rectifier. And, withal, an inspiration is given from this book: multi-interdisciplinary research can achieve novel outcomes. For example, considering power electronic converter only from the circuit theory, the factors that promote the development of power electronic technology show less vitality. Switched linear system theory, however, draws new elicitation for the study of power electronic converters. It is even possible to achieve further discoveries, tap the potentials, and take full advantage of the new characteristics of power electronic converters. Therefore, it is interdisciplinary that enlightens the future direction in research of power electronics technology.