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Multilevel converters (MLC) are now a standard solution for medium-voltage (MV) high-power applications and several modulation techniques have been reported in literature. However, high-power applications require low device switching frequencies to reduce the dominating switching losses and thus improve the overall efficiency of drive system. On the other hand, total harmonic distortion (THD) of current...
This paper presents about the control switching strategies of switching frequency by using the multilevel inverter. In previous topology inverter, 2-level inverter is commonly implemented by using direct torque control technique. However, this inverter has some major problem issues which occur due to the limitation of capability the semiconductor device. Basically, there exist two problems; Firstly,...
The paper presents closed-loop electric vehicle (EV) drive with 5-phase induction motor operating with switched-autotransformer (LCCAt) inverter. Electrical drives with five-phase induction motors are considered for application in electric vehicles. Space vector modulation (SVM) is the most common option for controlling a five-phase inverter. However, if the battery level cannot ensure the controllability...
Neutral-point (NP) voltage oscillation amplitude, THD of output voltage and the switching frequency of the inverter are the three key performance indices in three-level neutral-point-clamped (NPC) inverter. Every element connects with each other and restricts each other, which indicates that to keep the three key performance indices balanced is the research focus of the modulation strategy for three-level...
Asymmetrical cascaded multilevel converters can generate more number of voltage levels for the same number of switching devices. Binary, Trinary and other different forms are available in literature. This paper has critically investigated such converters from the point of view of optimizing the number of levels. A mathematical tool to analyze the possibility of any asymmetric ratio for various three-phase...
In this paper, a direct torque hysteresis controller (DTHC) driving a permanent magnet synchronous machine is discussed. A two-level, three-phase conventional inverter is used as means of power conversion. Advantages such as a low switching frequency as well as further opportunities of the DTHC are specified. The simulation results show a high degree of potential for the DTHC in future applications.
This paper presents a comparison between three switching techniques that can be used in three-phase four-wire Shunt Active Power Filters (SAPFs). The implemented switching techniques are: Periodic-Sampling (PS), Triangular Carrier Pulse-Width Modulation (TC-PWM) and Space Vector PWM (SVPWM). The comparison between them is made in terms of the compensated currents THD%, implementation complexity, necessary...
Optimal Pulse Patterns (OPPs) permit setting the switching frequency of power converters to a low value without compromising on Total Harmonic Distortion (THD). This paper presents the algorithm of calculating OPPs for Medium Voltage converters. The calculation procedure is explained in detail. Results are discussed and an efficient method is proposed to speed up and simplify calculations.
Common-mode voltage (Vcm) generated by voltage inverters is observed on motor windings. This voltage may induce bearing currents, which can eventually damage AC motors and cause larger common-mode currents. Many methods are proposed to eliminate or reduce the common-mode voltage. Most of these methods reduce the DC-bus voltage utilization and increase the output voltage harmonics. This paper introduces...
This paper presents a novel DC-link voltage balancing algorithm for a 3-level DC/AC traction inverter drive. In this topology, two DC-link capacitor voltages and three-phase line currents are measured, to generate the control pulses for the traction inverter, based on space-vector pulse width modulation (SV-PWM) scheme. Depending on the states of the two DC-link capacitors, redundant voltage vector...
There is an increasing interest in two-stage four-leg matrix converter (3×4TSMC) which provides a neutral connection for potential imbalanced loads. However, the fourth leg will worsen its operation performance unexpectedly, even if connected to the balanced loads. By means of analysis and calculation, it is found that the input filter capacitor voltage fluctuation will transfer to the output in the...
A new space vector modulation method for common-mode voltage reduction in four-level nested neutral point clamped (NNPC) inverter is proposed in this paper. The proposed method employs switching states with minimal absolute common-mode voltages to synthesize given reference vectors. A variety of virtual vectors are constructed to facilitate the synthesis. The effect of dead time on common-mode voltage...
DC to AC conversion technology has succeeded in obtaining high power quality (voltages and currents) using multilevel inverters. These inverters can generate several levels of voltage that reduce the harmonic distortion of the generated sine waves in the AC side. However, the output voltages always are discrete, so a non-negligible harmonic distortion remains. This distortion can be reduced by increasing...
In this paper, a nineteen level dodecagonal voltage space vector structure is proposed for the first time, by cascading two asymmetric three level inverters with isolated H-Bridges. The dodecagonal structure is made possible by proper selection of DC link voltages and switching states of the inverters. The proposed scheme retains all the advantages of multilevel topologies as well the advantages of...
This paper proposes an improved sensorless matrix-converter IPMSM drive system using a high frequency injection method. By suitably choosing different virtual dc-bus voltages and compensating the duty cycle of the switching states, the estimated position error can be obviously reduced. A 32-bit digital signal processor, TMS-320LF-2407A, is used to execute the rotor position estimation and the whole...
An original analytical expression is presented in this paper to obtain optimal currents minimizing the copper losses of a multi-phase Permanent Magnet Synchronous Motor (PMSM) under fault conditions. Based on the existing solutions [i]opt1 (without zero sequence of current constraint) and [i]opt2 (with zero sequence constraint), this new expression of currents [i]opt3 is obtained by means of a geometrical...
A drive train system (DTS) powered by an ideal voltage source and driving a permanent magnet synchronous motor (PMSM) is discussed in this paper. A two-level, three-phase conventional inverter with no harmonic filters on both AC and DC sides is used as means of power conditioning. This DTS is modelled as a double oscillator according to a simplified drive train in an electric vehicle. Commonly used...
In this paper, high bandwidth current control for an open-end winding induction motor is realized with deadbeat control. A deadbeat current controller achieves higher gain than a PI current controller by compensating for the error caused by the digital sampling delay. The response of a deadbeat controller is directly influenced by its sampling frequency, while that of PI controller depends on gain...
This paper presents the design and the prototype implementation of a three-phase power inverter developed to drive a motor-in-wheel. The control system is implemented in a FPGA (Field Programmable Gate Array) device. The paper describes the Field Oriented Control (FOC) algorithm and the Space Vector Modulation (SVM) technique that were implemented. The control platform uses a Spartan-3E FPGA board,...
This paper proposes a multilevel indirect matrix converter (IMC) topology with multilevel output voltages and its simplified carrier-based pulse-width modulation (PWM) method. This converter consists of two rectifier stages used in traditional three-phase IMC and three-level T-type voltage source inverter. Beside a proposed IMC topology, the carrier-based PWM method suitable for this converter is...
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