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For a particular five-phase synchronous machine, this paper investigates the sensitivity of a vectorial control strategy on the required peak phase voltage whose value is fundamental for the choice of the DC bus voltage. The specificity of the machine is that the first and third harmonic components of the back electromotive force (back-emf) have the same amplitude. As a consequence, the torque can...
The modular multi-level converter is an upcoming topology for drive application in the megawatt power range. This paper presents a comprehensive reliability survey for this kind of converter which can be used for its optimal designing. In this survey, converter total failure rate, is calculated for different number of output levels to find the optimal condition in which converter can provide the best...
In single-phase inverters, the proportional control is paralleled with the repetitive control to improve the dynamic performances. Meanwhile, in order to guarantee the stability of system, the static error cannot be eliminated in this control. This paper proposed an advanced scheme for the repetitive control to achieve zero error tracking. Taking the advantage of comb filtering by using Fourier transform...
This paper presents the DC analysis of the Negative Output Elementary Luo Converter (NOELC), which includes the continuous-conduction mode (CCM) voltage gain and the boundary condition between the CCM and the discontinuous-conduction mode (DCM). The main features of the NOELC are the high gain with small ripple and the reverse output. Additionally, we address the parameters design of the NOELC and...
In order to correct the power factor and limit the flow of harmonics in the source, the effectiveness of active power filters associated to control law is no longer to be demonstrated. Almost all of these methods are designed for a perfect sinusoidal source and do not produce sinusoidal current when the voltages are disturbed. The work developed here concerns active filtering on a perturbed network,...
This paper considers the stabilization problem for a harmonic oscillator system under positive delayed velocity feedback control. By using the τ-decomposition technique and imposing a simple constraint on the feedback gain, some necessary and sufficient conditions are established such that the harmonic oscillator can be globally asymptotically stabilized if and only if the time-delay for the control...
A second-order integral flux observer (SOIFO-FLL) with dc component and harmonics attenuation capability is proposed for PMSM sensorless control in this paper. Due to the nonzero integral initial value, parameter mismatch, converter nonlinearities and detection errors, the estimated rotor flux by the conventional methods, pure integrator and low-pass filter (LPF) suffer the dc component and harmonics...
In this paper, a novel hybrid DTC scheme is proposed for asymmetric six-phase PMSM drives, which can achieve faster dynamic response of classical ST-DTC scheme and good steady-state performance of classical SVM-DTC scheme. The key is that a completely novel control strategy for torque and stator flux is designed. Different torque control methods are adopted under dynamic mode and steady-state mode...
In three-phase grid-tied inverter, grid voltage feedforward is helpful to improve grid-tied power quality for strong grid condition. This paper found that the voltage feedforward had different effect on power quality under weak grid condition compared with that in ideal grid condition. And recent reported studies show that grid voltage feedforward has negative effect for grid-inverter system stability...
The fast and accurate control of renewable energy grid side converter (GSC) under normal and abnormal grid conditions is necessary to ensure the injection of high quality power and to enhance the power system stability. Accurate control of GSC is achieved by the stable and fast response of current and PQ controllers. In the event that the grid voltage becomes unbalanced due to the presence of grid...
This paper proposes a frequency observer based control of a solar energy conversion system (SECS). The proposed control eliminates the DC offset and harmonics current and provides fundamental component of load current. The mathematical analysis of the control is corroborated and discussed in terms of filtering capabilities. Besides, capability of maximum power extraction, it integrates maximum extracted...
Power quality is an important aspect in data centers and power system operators prefer data centers with high standard power quality. Modern data centers consume large amount of electrical power. As the cooling systems are accounted for 40% of the total power consumption in data centers, energy efficiency in this sector is of high importance. This research investigates if the existing energy efficient...
This paper proposes a transient modeling and analysis method for the fractional-order DC-DC converters in continuous conduction mode (CCM), in which a fractional-order Buck converter is taken as an example. By extending the usage of equivalent small parameter method (ESP), the converter is modeled by a general state vector differential equation. Then by adopting the principle of harmonic balance,...
The basic spatial modulation effects of induction machines caused by slotting and saturation, have been analyzed for exploitation in speed sensorless control. With increasing load level, additional spatial harmonics arise, acting as disturbance and deteriorating sensorless control performance. In view of the fact, that induction machines for application in traction systems (e.g. public or cargo transportation)...
A novel discrete sinusoidal signal integrator (DSSI) structure is proposed in this paper for single grid-tied inverters. The DSSI provides an adjustable gain and bandwidth at the expected frequency and a highly attenuated gain at other frequencies which make the DSSI based controllers obtain the zero steady-state error tracking performance of arbitrary frequencies. The performance of the conventional...
With the increasing penetration of renewable energy generations such as solar and wind power, negative impacts of the large-scale integration of renewable energy on the bulk grid cannot be ignored. Thus, grid integration testing of inverter-coupled renewable energy is essential. For this reason, a high power gird simulator capable of emulating various types of realistic grid conditions is needed for...
In an islanded microgrid, harmonic current is controlled (or shared) by modifying the effective impedance in the path of harmonic current. This effective impedance includes line impedance and the internal impedance of the generation unit. Reported works consider the aforementioned impedances as separate entities and their combined effect in harmonic current flow has not been discussed so far. This...
In this paper, in order to replace a conventional electric linear actuator which is consist of rotary PM machine and ball screw, a novel double-sided five-phase modular linear permanent magnet synchronous machine (MLPMSM) is proposed and designed with the same volume. The basic structure of the machine is firstly described and the major dimensions of one module are then optimized to acquire the largest...
H-bridge cascaded inverter can be used for harmonic compensation in medium and high voltage systems. As the equivalent switching frequency is high, L-type filter is commonly used for H-bridge cascaded inverter. Meanwhile, considering device safety and filtering effect, inductance value of L filter is large. When the command current contains harmonics, especially high harmonics, large connecting inductance...
The high-frequency characteristics of power cables are very important in many application situations, especially the current distributions of power cables in the high frequency band. This paper mainly presents two important integral equation methods, volume integral equation (VIE) and surface integral equation (SIE), which can be applied to arbitrary shape of cross section of cables. This paper also...
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