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This paper presents discontinuous pulse width modulation (DPWM) scheme for a modular multilevel converter (MMC) to achieve an advanced switching losses reduction. The MMC is considered to be one of the most attractive multilevel topology for high-power applications because of the features of its high power quality, modularity, and availability. However, the MMC has large switching losses because of...
This paper proposes optimal switching period phase-shifted method for slave inverter to reduce grid current ripples in synchronized two parallel three-phase grid-connected voltage-source inverters (VSI). In parallel operation, a 180 degree phase shifted method generally takes of advantage of reducing grid current ripples in same DC-link voltage for each grid-connected VSI. However, in case of unequal...
This paper proposes an improved phase-shifted pulse-width modulation (PS-PWM) method for a three-phase cascaded H-bridge (CBH) multi-level inverter. In the proposed PS-PWM method, the switches at one leg of H-bridge cell (HBC) only operate and the switches at other leg are clamped. Therefore, the number of the multi-carrier signals depending on the voltage level can be reduced in half compared to...
In two-level PWM rectifiers, two common control strategies are respectively VOC (Voltage Oriented Control) and DPC (Direct Power Control). In high power applications, the converter performance may suffer seriously from the non-ideal characteristics of the sampling and control system. The effects of the non-ideal characteristics will be analyzed in this paper for classic VOC, DPC and PDPC (Predictive...
In this paper, a new single-phase multilevel inverter topology suited for distributed DC sources is proposed. The proposed inverter is comprised of a voltage-level generator connected in series to the input of the classical H-bridge. The voltage-level generator is only able to generate positive DC voltage levels at its output. The H-bridge is used to generate the negative and zero voltage levels....
In order to make the buck converter obtain smaller voltage ripple and higher efficiency at the same time, the pulse skipping width modulation (PSWM) mode in buck converter application is proposed in this paper. This novel controlling mode combines the advantage of pulse skipping modulation (PSM) with improving voltage ripple especially in lighter load and pulse width modulation (PWM) having higher...
DC current is an important parameter for the three-phase voltage source converter (VSC). It determines the thermal and reliability status of DC-link capacitor or battery. Analysis and prediction of DC current is associated with three-phase AC current and its ripple, together with the pulse-width-modulation (PWM) method. Based on the AC current ripple prediction method, this paper gives a general DC...
Zero-Voltage and Zero-Current-Switching (ZVZCS) phase-shifted full-bridge (PS FB) pulse-width-modulated (PWM) converter, which can achieve Zero-Voltage-Switching (ZVS) of the leading leg and the Zero-Current-Switching (ZCS) of the lagging leg in a wide load range. It has the advantages of simple structure, less duty cycle loss and easy to implement soft switch and so on. In this paper, the working...
For most of the Multilevel Converter (MC) applications a commonly discussed issue is the maintenance of balance between the energy storage elements from the SubModules (SM). In applications where a battery pack is also part of the SM storage, such as STATCOMs or motor drives, the SM voltage is not in linear relation with the State Of Charge (SOC) of the entire battery; thus, the balancing becomes...
To take out a variable frequency variable amplitude output voltage a new single-phase H-bridge multilevel inverter (MLI) topology is constructed through VFISCPWM modulated semi-cross switched voltage sources along with a hybrid pulse width modulation (PWM) strategy. The principle avoids a shrewd attitude to employ PWM approach only for a meticulous H bridge that serves to produce the desired level...
Z-Source inverters can overcome some of the limitations, inherent in traditional Voltage Source and Current Source Inverters and can provide boosted outputs. Most of the literature on Z-source inverters deals with 3-phase or 1-phase bridge inverters. This paper proposes a Single-Phase Z-Source Push-Pull Inverter topology. This scheme has several advantages compared to basic Z-source full-bridge inverter...
This paper presents a novel stand-alone power system using a three to four phase matrix converter (MC) for use with renewable energy sources such as a micro hydro turbine or a tiny wind turbine with a permanent magnet synchronous generator (PMSG). MCs are able to convert AC power to AC power directly without using DC link capacitors, and AC to DC conversion is also possible because DC is considered...
As the power demand increases rapidly in the electricity market the use of renewable energy sources also increasing. Renewable sources are significantly different from the traditional power sources due to their stochastic nature. Therefore it is a tough task to integrate renewable energy sources with the existing utility grid. In order to ensure the grid reliability, current controlled Pulse Width...
Four-level hybrid-clamped (4L-HC) inverter is a newly proposed topology which is suitable for high-performance medium-voltage drives. This paper proposes a multi-objective optimization strategy for this 4L-HC inverter. The central DC-link capacitor and flying capacitor voltages are regulated by a modified phase-shifted PWM. The upper and lower capacitor voltages are balanced by zero-sequence voltage...
This paper focuses on the determination of suitable carrier based pulse width modulation (PWM) switching and control methods for grid connected modular multilevel converters (MMCs). Characterization of various level-shifted and phase-shifted carrier based PWM methods are provided in terms of output voltage waveforms both for N+1 and 2N+1 level output phase voltages. Carrier based PWM method based...
This paper proposes a cell-balancing circuit for a series-connected battery string. The proposed cell equalizer is an active cell-balancing circuit with a multi-winding transformer based on a forward DC-DC converter. The advantage of the proposed cell balancing circuit is that it can use less number of active power switches than other forward converter circuits. The proposed circuit operates for all...
This paper presents a simple method for detection of commutation instants of the extensively used low power brushless DC motors. In the proposed method the commutation signals are obtained without any phase shift circuit which is required in the conventional sensorless control methods. So the overall cost is decreased and the sensorless control is easy to be implemented. In the proposed method, instead...
Compared with the conventional buck-boost three-level inverters, the Z-source neutral-point-clamped (NPC) inverters have more simple structure with improved output waveform quality. But the neutral-point potential unbalance problem is still a drawback for their applications. Based on the research of SPWM modulation method and the analysis of the effect of the shoot-through states on the neutral-point...
As the increase of large-scale distributed generation system, the interest in the efficiency of the inverter has been higher. In this paper, the power losses are classified and calculated according to the switching states of the three level NPC inverter and three level T-type inverter. And they are compared with the results from the PSiM thermal module simulation. These power loss comparisons are...
This paper presents a comprehensive modeling, simulation and computational implementation of buck converter. Four modeling approaches of buck converter including mathematical, circuitry, transfer function and state space modeling are presented. Each modeling approach is demonstrated with various computational implementation methods including graphical, functional block and text based programming in...
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