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Vectorial PWM for Basic Three-Phase Inverters
Published in Dorin O. Neacsu, Switching Power Converters, 2017
Previous chapters have explained the need for pulse width modulation (PWM), control of three-phase converters and presented some conventional methods that generate PWM on each phase independently. Some limitations in their practical implementation have stimulated efforts to find other principles to generate PWM controls. The most remarkable is the analysis of the three-phase inverter in the complex plane by the Vector Space theory. Understanding the mathematical representation of the inverter operation in the complex plane provided a tool for the generation of a new PWM algorithm called space vector modulation (SVM). (Note the difference between a vector space, which means a space of vectors, and a space vector, which means a vector with a spatial displacement.)
Three-Phase Photovoltaic Systems: Structures, Topologies, and Control
Published in Frede Blaabjerg, Dan M. Ionel, Renewable Energy Devices and Systems with Simulations in MATLAB® and ANSYS®, 2017
Tamás Kerekes, Dezső Séra, László Máthé
The most often used modulation method for three-phase inverters is the space vector modulation (SVM). This modulation method uses the advantage of signal injection in the CMV as the THI-PWM method; however, in the beginning, it was treated as a totally different modulation technique. By analyzing all the possible switching states in a VSI, six active and two zero-sequence voltage vectors (when either the three upper or the three lower switches are simultaneously on) can be generated. In a d–q plane, the six active vectors form a hexagon as shown in the red hexagon in Figure 4.4.
An Efficient Carrier-Based Modulation Strategy for Five-Leg Indirect Matrix Converters to Drive Open-End Loads with Zero Common-Mode Voltage
Published in Electric Power Components and Systems, 2019
Van Van Huynh, Tuyen D. Nguyen, Van-Thanh Dao, Quoc-Hoan Tran
Besides the development of the MC-based topology for the OEL applications, modulation strategy has also been investigated in recent literature to drive the MC effectively. The space vector modulation (SVM) strategy has been widely used in the early works because it can provide excellent performance regarding low output harmonic distortion and high VTR. However, the SVM strategy requires many calculations and lookup tables to identify the dwell time and synthesize the switching pattern, respectively [11, 12, 16]. Moreover, the effort to eliminate common-mode voltage (CMV) across the load phase makes the SVM strategy becomes more complicated due to the additional compensating calculation [13]. To achieve the zero CMV, the appropriate switching sequences are developed in this paper by using both active and zero vectors to generate the desired output voltage. The new switching sequences ensure zero-current commutation in the rectifier stage; hence the power switching loss and complicated multi-step commutation are avoided. Furthermore, a simple carrier-based modulation (CBM) strategy is proposed to control the five-leg IMC fed OEL scheme instead of the complex SVM strategy. Thanks to the CBM strategy with fewer computations, the five-leg IMC can drive a three-phase OEL efficiently as well as maintain approximate zero CMV across the load phase. The effectiveness of the proposed CBM strategy is verified by simulation and experimental results.