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There are two major factors restricting current loop bandwidth, switching frequency and digital delay. Digital delay includes A/D sampling time and PWM duty cycle update. The calculating delay is the major source of delay in the loop. The bandwidth expansion strategy was proposed. Double stator current sampling and double PWM duty cycle update were achieved in a carrier period. This paper chooses...
A new asymmetrical hybrid multilevel inverter topology is presented. The new topology improve the number of the output voltage level greatly through cascading two five-level H-bridge cells. A hybrid PWM strategy is proposed for the new topology that the switches of different cells works in different switching frequency to low switching losses. Lastly, an experimental 17-level asymmetrical inverter...
This paper proposes a two stage boost converter circuit for the grid connected photovoltaic system. Each stage is controlled separately by opposite pulse width modulated signal. Due to nonlinear I-V characteristic of the photovoltaic cells, the converter circuit is designed for the range of input voltage 35 to 60 V, 350 V output voltage and maximum output power of 525 watt. Dynamic modeling of the...
Present Traffic Light Controllers (TLC) are based on microcontroller and microprocessor. These TLC have limitations because it uses the pre-defined hardware, which is functioning according to the program that does not have the flexibility of modification on real time basis. Due to the fixed time intervals of green, orange and red signals the waiting time is more and car uses more fuel. To make traffic...
This paper deals with the implementation of FM-ZCS-QRC fed Dc servo drive using micro controller. The salient feature of QRC is that the switching devices can be either switched on at zero voltage or switched off at zero current, so that switching losses are zero ideally. Switching stresses are low, volumes are low and power density is high. This property imparts high efficiency and high power density...
In power electronics efficiency improvement is constantly being sought out through venues such as improved topologies or improved devices. Series loaded resonant (SLR) DC-DC converter is a type of soft-switching topology widely known for providing improved efficiency. This paper investigates the efficiency and transient performance of SLR when a new type of diode called Super Barrier RectifierTM is...
The multilevel inverter utilization have been increased since the last decade. These new type of inverters are suitable in various high voltage & high power application due to their ability to synthesize waveforms with better harmonic spectrum and faithful output. This paper presents, two proposed scheme adopting the multicarrier pulse width modulation concept. The multicarrier pulse width modulation...
In this paper, a new control strategy of stator-flux orientation for flux-switching permanent magnet (FSPM) motor based on voltage space-vector is proposed. The fundamental relationship and equalization between the two magnetic fields where the magnets are in the stator and rotor, respectively, are analyzed. The space-vector pulse-width modulation technique is applied to the FSPM motor drive in which...
With the increasing of the wind turbine capacity, inverter paralleling is one of the best approaches for MW-level wind power converter system design. This paper presents a new control algorithm for paralleling inverters based on SVPWM, which can reduce the output harmonic currents and inhibit the circulating current between the inverters. The detailed algorithm principles and mathematic derivations...
Pulse width modulation (PWM) inverters are widely applied to control motors. It will often increase the eddy current losses in the motors. In this paper, the authors deal with the effects of eddy current losses with amplitude modulation and switching frequency in an induction motor fed by PWM Inverter. The method is employed by a time-stepping finite element analysis (FEA). The FEA model of motor...
This paper proposes the predictive delta-modulation current regulator (PDCR) algorithm for use with the switched reluctance motor. The proposed PDCR combines features of the convention delta-modulation current regulator, which has simple structure and does not require any motor parameters, and the predictive current control, which estimates the current error signal of the next sampling period using...
This paper presents a high performance direct torque control (DTC) theme for the induction motor (IM). To solve those problems associated with conventional DTC, such as high current, flux and torque ripple, variable switching frequency, the space vector modulation (SVM) is implemented in the DTC to guarantee the constant switching frequency of the inverter. Meanwhile, the design of a robust speed...
This paper presents a three-level rectifier with reduced number of power switches based on one-cycle control. Only six power switches with voltage rating of half DC-link are adopted in this multilevel rectifier. A nonlinear control method, one-cycle control, is used to control the rectifier. The controller is composed of some integrators with reset, flip-flops, comparators and linear components, which...
A dual-buck full-bridge inverter (DBFBI) is proposed. The inverter solves the shoot-through problem of each bridge leg which exists in bridge-type inverter, so the dead time between the switches neednpsilat be set, and thus waveform quality of the output voltage and reliability of the inverter can be improved. The DBFBI also increases the input-voltage utilization rate and reduces the voltage stresses...
A modified direct torque control (DTC) scheme for surface permanent magnet synchronous machine (SPM) is investigated in this paper, which features in very low flux and torque ripple and almost fixed switching frequency. It is based on the deadbeat control of the flux and torque. Simulation results show that the flux and torque ripples are greatly reduced when compared with those of the basic DTC....
In this paper introduced a design of the active controllable energy feedback device (ACEFD) based on dsPIC30F DSP and d-q controller. Through establishing the synchronous rotating coordinate system (dq) model, we may achieve the decoupling feed-forward control method; the advantages are discussed in the following paragraphs. We also analysis the inner current control model and calculate accurately...
Based on feedback of the stator current phase, a new control strategy of doubly-fed induction generator (DFIG) is proposed. Under the condition that stator current amplitude maintains at rated value, the required rotor control voltage is directly calculated by the stator flux, rotor rotating speed, stator current phase and its corresponding error. Constant converter switching frequency and stator...
As an essential component in magnetic resonance imaging (MRI) systems, the gradient amplifier plays an important role for good image quality. A platform of stacked high and low level H-Bridge circuit is built to fit the high-dynamic and high-steady requirements of the gradient amplifier. Both high current slew rating and low steady ripple can be achieved by using the two H-Bridges, one with high voltage...
Direct torque control (DTC) used in AC-drive locomotive control system, which has been developed in the recent decade, is a control strategies with high dynamic and static performance, and it directly generate the inverter gate control signal by judging the output of the stator flux, torque hysteresis comparator and the position information of the stator flux that cause the switching frequency unfixed...
With the development of superconductive technology of high temperature, multilevel current source converter (CSC) will be widely used in power system. The selected harmonic elimination pulse width modulation (SHEPWM) technique for multilevel CSC is presented in this paper. Simulation results prove the advantages of the method such as low switching frequency, high output current quality, high output...
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