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Pole phase modulated (PPM) multiphase induction motor (IM) drives for applications like ship propulsion starts with high pole mode of operation to provide high starting torque required and then switch over to low pole mode of operation for steady run with high speeds. The performance of the nine phase PPM IM drive in case of nine phase four pole operation is inherently good due to high phase number...
The increase in non-linear loads in the electrical network deteriorates the voltage waveform quality. One of the most used methods to correct the quality lack is to use shunt, series or mixed topologies of active power filters. Mixed filters can compensate loads that generate voltage harmonics and current harmonics, but the economic investment is high. Commercial shunt filters are more widespread...
A phenomenon that occurs when using the DQ Transformation to obtain the compensation references in active filter applications is presented in this paper, in which new harmonics that had not existed originally in the system, are injected to it. Although these new injected harmonics have very low magnitude, they do exist and correct processing must be assured in order not to increase their magnitudes...
This paper presents a control scheme for Static Compensators applied in distribution systems (DSTATCOM), that are used for regulation of voltage magnitude at point of common coupling (PCC) and it also has the function of eliminating harmonics of voltage through PCC-voltage-detection method. Voltage-magnitude regulation is accomplished through quadrature-current injection at PCC and harmonic mitigation...
Accurate computational simulations are highly required to properly assess the performance of power grids under high penetration levels of non-conventional generation which connects to the grid via static power converters. However, software packages that are typically used to perform power system analysis may not necessarily have the capacity to efficiently perform detailed simulations of power grids...
In this paper a novel hybrid harmonic compensation approach for non-linear loads is developed and analysed. This technique provides compensation for current harmonics coming from a nonlinear load and reactive power regulation even during grid's voltage disturbances. The method could be implemented on any Series Active Filter. Meanwhile the Transformerless configuration (TSeAF) is selected in this...
When modeling resonant inverters considering the harmonic balance method, the order of the obtained transfer functions is twice the state variables number. This is explained because two components are considered for each state variable. In order to obtain a simpler transfer function model of a halfbridge series resonant inverter, different techniques of model order reduction have been considered in...
In this paper a new single-phase five-level buck-boost active rectifier is introduced called capacitor tied switches (CTS). The proposed rectifier has two independent DC outputs that can be connected to two different loads. Different switching states and the average mode of the proposed topology are analyzed to design the associated controller aims at regulating the two output DC voltages, generating...
A new three-phase three level inverter topology is proposed in this work. The presented structure is characterized by the use of a Bidirectional Neutral Point Clamped (BNPC) in order to compensate harmonics and to eliminate the reactive power and load varying under sever source voltages conditions. The control technique is based on Lyapunov candidate. An energy-based Lyapunov control strategy is developed...
The output voltage references in grid connected Voltage Source Converters must be limited according to the available dc voltage to avoid over-modulation and windup of the current controllers. This may be especially critical for Active Power Filters (APFs), since uncontrolled over-modulation can cause unintended harmonics in the output voltage and interfere with the harmonic compensation. This paper...
A fault-tolerant tandem converter, based on a current-source converter and cascaded multilevel voltage-source active filter, is proposed as the grid interface for a 10MW superconducting direct-drive wind turbine generator. The converter reduces the possibility of a short-circuit fault, an issue with the extremely low generator reactance, while having a significantly lower DC capacitance requirement...
Non-linear optimal control using collocation and multiple shooting is investigated in this paper to generate the current reference signal for the lower level control of an active filter in a marine vessel with diesel-electric propulsion. The optimization objective is aimed at using the active filter for system-level minimization of Total Harmonics Distortion with the minimum rating of the active filter...
This paper describes a rare-earth-free synchronous motor where space harmonic power is utilized for field magnetization instead of permanent magnets for automotive applications. The stator has a concentrated winding structure, and the rotor has separate two types of windings, i.e., an induction coil that retrieves mainly the second space harmonic and an excitation coil for the field magnetization...
Linear induction motors (LIMs) have become a competitive alternative in electric traction. Three-phase LIM commonly uses double layer overlapping distributed windings. Although this winding configuration results in more sinusoidal magneto-motive force (MMF), hence good machine performance, it has relatively bulky end windings and uses either half-filled slots or overhanging coil sides at the machine...
The curved PM linear motor is a particular type of linear motor that can satisfy some special utilities. This paper presents an analytical model of the motor based on harmonics analysis. The harmonics of magnetic field induced from PMs and armature windings are obtained using the equivalent MMF source and the slot star, respectively. The effect of the armature slots on the flux distribution is analyzed...
Nowadays in high-power industrial processes, multipulse cycloconverters are the most commonly used converter for high power mill drives. This paper propose an analysis of the interharmonics currents behavior under an unbalanced load, injected by a Cycloconverters (CCVs) with 12- pulse configuration and multi-winding transformers. Three-phase transformers with two secondary windings with star and delta...
Carrier based PWMs are easy to implement for the multilevel inverters compared to space vector based implementation. This paper proposes two carrier based PWMs called Carrier Overlapped Sinusoidal PWM (CO-SPWM) and Carrier Overlapped Switching Frequency Optimal PWM (CO-SFO-PWM) methods for the three-level cascaded inverter. The basic idea uses adding a simple offset to the carriers that create an...
Modular multilevel converters provide high power quality, high reliability and flexible voltage and power scalability. However, large capacitor voltage ripple is one of the main drawbacks of this topology. This ripple reduces the capacitor lifetime and, due to the large capacitance required to limit it, increases the size and cost of the converter. In this work, the capacitor voltage ripple is expressed...
DC-link electrolytic capacitors are used in single phase solar PV inverters to suppress second harmonic and switching voltage ripples. Electrolytic capacitors are less reliable than other components of PV system. Degradation of these capacitors affects the performance of the system. Reduction in capacitance and increase in equivalent series resistance (ESR) due to ageing increases ripples in dc voltage...
The utilization of multi-cell converters, through the use of low voltage semiconductors, has permitted to implement medium and high voltage applications as PV farms and AC drives. In conventional AC drives, this converter requires an input multipulse transformer, which allows the low frequency harmonic cancellation that are generated by the three-phase diode rectifiers included in each cell. This...
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