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Unless over modulation is adopted, utilization of DC bus of the Modified Space Vector Modulation (MSVM) is a drawback that has severely limited the applicability of this modulation technique. This paper presents some solutions that, looking for a good compromise between increasing the use of DC bus and reducing common mode currents, allow to apply MSVM to most electrical drives on the market. Furthermore,...
The device switching frequency of current source converters (CSC) in high power medium voltage applications is usually several hundred hertz. Selective harmonic elimination (SHE) has been the dominant modulation scheme because of its ability to eliminate unwanted low order harmonics at low switching frequency. Conventional space vector modulation (SVM), as another CSC modulation method, provides variable...
Hybrid vehicles are a characteristic feature of the daily traffic yet, with growing fuel costs and other factors increasing their importance in the nearest future even more. Nevertheless, hybrid vehicles are not a mass product up to now. Although the life cycle costs of the hybrid cars are usually smaller than the costs for comparable fuel vehicles, the main purchase criteria for vehicles are still...
Sensorless control of ac machines which is able to work even at zero speed can be realized using high frequency excitation. Different schemes have been presented recently, which use transient excitation caused by the switching of the voltage source inverter. Transient excitations of only one pair of test vectors are applied for each measurement in this paper. The signals resulting from transient excitation...
This paper describes a novel digital control solution for isolated DC-DC converter. Compared with non-isolated DC-DC converters, isolated ones need to realize isolation of control between primary and secondary side. In this paper, the whole digital control system is implemented using two FPGAs. The one on the secondary side includes a compensator (PI regulator), a high resolution digital PWM (DPWM),...
Recently, the V2 type of constant on-time control has been widely used to improve light-load efficiency. In V2 implementation, the nonlinear PWM modulator is much more complicated than usual, since not only is the inductor current information fed back to the modulator, but the capacitor voltage ripple information is also fed back to the modulator. Generally speaking, there is no sub-harmonic oscillation...
This paper focuses on the non-inverting buck-boost converter supplying an adjustable DC voltage to a WCDMA RF power amplifier (RFPA) in order to improve the system efficiency under different transmitted RF power levels. It is shown that precise output voltage positioning and low output voltage ripple over a wide output voltage range, including buck, boost and buck/boost transition modes, can be accomplished...
This paper proposes a generalized method for the generation of space vector pulse width modulation (SVPWM) signals for multilevel inverters. The objective of the proposed method is to eliminate the need of lookup table and sector identification required in the implementation of SVPWM for multilevel inverters. In the proposed method, the actual sector containing the tip of the reference space vector...
In traditional three-level neutral-point-clamped (NPC) inverters, a major issue is capacitor voltage imbalance, which results in low order harmonics. The compensation of the capacitor voltages often require additional control complexity, which cannot be conveniently implemented. The "alternative phase opposition disposition" (APOD) modulation method used in traditional NPC topologies also...
This paper proposes a novel fixed-frequency sliding mode (SM) controller of buck converters in CCM (continuous conduction mode), which almost holds the advantage of robustness and fastness of SM control. The design method of a new SM controller for buck converter is given. Simulation and experimental results verify the validity and feasibility of the fixed-frequency modulation method in Buck converter...
The pulse width modulation strategies of Z-source inverter can be classified into two categories according to the two different shoot through state insertion ways. This paper focuses on a loss analysis of Z-source inverter using the both PWM strategies. Based on the semiconductor device loss model, the losses evaluation formula are derived firstly for both cases, then a loss-oriented comparison of...
Multilevel inverters have been widely used in medium and high voltage applications. Selective harmonics elimination for the staircase voltage waveform generated by multilevel inverters has been studied extensively in the last decade. Most published methods on this topic aimed at solving high-order multi-variable polynomial equation groups derived from Fourier series expansion. A totally different...
Achieving faster dynamic response is one of the big challenges for the future microprocessor voltage regulators (VR). It is well known that the system bandwidth needs to be higher to get a faster dynamic response but the system bandwidth is usually limited by the phase shift near the switching frequency. In this paper, the existing theories for this phase shift and efforts to achieve a faster transient...
This paper presents the control of three-phase inverters connected to the grid by using the concepts of the instantaneous abc theory and the effective apparent power Se. These concepts allow the control of the three-phase inverter from a phasorial point of view both in magnitude and phase. The regulation of the instantaneous reactive power Q allows the instantaneous control of the phase delay phi...
For the purpose of reducing power loss of power converters, switching power converters are generally used. High frequency operating power conversion realizes small size and lightweight converters. And high frequency switching power converters enlarge new application spheres like mobile equipments. As for the switching power converters, pulse width modulation (PWM) method is generally used. But in...
In the course of the more electric aircraft program active three-phase rectifiers in the power range of 5 kW are required. A comparison with other rectifier topologies shows that the three-phase Delta-switch rectifier (comprising three Delta-connected bidirectional switches) is well suited for this application. The system is analyzed using space vector calculus and a novel PWM current controller concept...
In this paper, a general solution for the theoretical PWM harmonic components is presented. Analytical solutions of harmonic components for all PWM schemes can be easily achieved by using it. The method is applicable irrespective of the pulse ratio between the carrier and the fundamental, and the computational requirements are essentially constant irrespective of the absolute value of the carrier...
This paper presents an extension of direct duty ratio pulse width modulation (DDPWM) to various topologies of matrix converters. In DDPWM, by using the concept of average over one switching period, the duty ratio which is compared with the triangular carrier waveform can be obtained so as to synthesize the desired output voltages. Owing to the per-phase modular structure of the DDPWM method, it can...
The staircase inverters are suitable for high power rating applications due to their low switching frequency and perfect harmonic performance. Because the switching signals are generated with delaying method traditionally, the dynamic regulation is poor. A novel waveform modulation technique for the staircase inverters is proposed in this paper, which adopts sequential sampling space vector modulation...
Multilevel inverters are traditionally seen as a step forward in DC/AC conversion, providing more output voltage levels, better quality of the generated waveform and lower switching losses than the two-level and can process higher voltages with a given forced commutated switch technology. There are also drawbacks associated with this technology: more switching devices and associated gate driver circuitry,...
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