Three-phase

About: Three-phase is a research topic. Over the lifetime, 16801 publications have been published within this topic receiving 159477 citations.

Improved Rotor Position Estimation Accuracy by Rotating Carrier Signal Injection Utilizing Zero-Sequence Carrier Voltage for Dual Three-Phase PMSM

Abstract: In this paper, the rotor position estimation accuracy of rotating carrier signal injection utilizing zero-sequence carrier voltage method for dual three-phase (DTP) permanent-magnet synchronous machines (PMSMs) is investigated. When utilizing the zero-sequence carrier voltage, the system bandwidth and rotor position estimation accuracy can be significantly enhanced. However, undesirable sixth harmonic estimation error occurs for single three-phase PMSM with rotating signal injection due to multiple saliency components in the zero-sequence carrier voltage. To solve such a problem, the existing methods require time-consuming offline measurements and complex structures. Fortunately, for the case of DTP-PMSM drives, thanks to the existence of additional degrees of freedom, two high-frequency signals can be injected independently for two winding sets. Therefore, by applying the optimum phase shift angle between the injected signals, a modified rotating carrier signal injection using zero-sequence voltage-based sensorless control strategy is proposed to suppress the sixth harmonic position errors. In addition, a new simple measurement method of zero-sequence carrier voltage is proposed where one voltage sensor is placed between the two isolated neutral points. The proposed method can achieve improved rotor position estimation accuracy with low computational burden. The experimental results verify the effectiveness of the proposed strategy.

Transient performance of three-phase self-excited induction generator during balanced and unbalanced faults

Abstract: A generalised dynamic model of a delta-connected three-phase self-excited induction generator (SEIG) has been developed using d-q variables in a stationary reference frame This model can handle symmetrical and unsymmetrical load and capacitor configurations, however, the SEIG performance during balanced and unbalanced faults has been studied, which include cases of extreme unbalance operation SEIG behaviour has been investigated considering the effects of main and cross flux saturation for load perturbation, three-phase and line-to-line short circuit, opening of one capacitor, two capacitors and a single line at the capacitor bank, opening of single-phase load, two-phase load, and a single line at load Simulated results are compared with experimental results and a close match between them validates the developed model

Evaluation of current ripple amplitude in three-phase PWM voltage source inverters

Abstract: Determination of current ripple in three-phase PWM voltage source inverters (VSI) is important for both design and control purposes, since this is the most popular conversion topology for energy conversion systems. In this paper the complete analysis of the peak-to-peak current ripple distribution over a fundamental period is given for three-phase VSIs. In particular, peak-to-peak current ripple amplitude is analytically determined as a function of the modulation index. Minimum, maximum, and average values are also emphasized. Although the reference is made to continuous symmetric PWM, being the most simple and effective solution to minimize the current ripple, the analysis could be easily extended to either discontinuous or unsymmetrical modulation, both carrier-based and space vector PWM. The analytical developments for all the different subcases are verified by numerical simulations.

Hybrid Space Vector Modulation Strategy for Torque Ripple Minimization in Three-Phase Four-Switch Inverter-Fed PMSM Drives

Abstract: Three-phase four-switch (TPFS) inverters are generally applied as cost-reduction topologies for permanent-magnet synchronous motor (PMSM) drives because of their reduced number of switching devices. However, undesirable torque ripples are produced by the inverter-fed PMSMs due to the application of nonsinusoidal voltages. Because the torque ripples are strongly influenced by the employed pulse width modulation (PWM) strategy, two commonly used switching sequences in TPFS inverter-fed PMSM drives are fully investigated based on the root mean square value of the torque ripples, in which the effects of the different equivalent zero vectors on the torque ripples are presented. Then, a hybrid space vector modulation (SVM) strategy is proposed to minimize the torque ripples by alternatively using the two equivalent zero vector synthesis approaches during a fundamental period. The sector division of the proposed hybrid SVM strategy is determined by the location of the stator current vector, which is quite different from the methods used in other SVM methods. Then, a simplified sector identification method is proposed to reduce the computational burden. The experimental results demonstrate that the proposed hybrid PWM strategy can effectively reduce torque ripples in TPFS inverter-fed PMSM drives.

A Versatile Unified Power Quality Conditioner Applied to Three-Phase Four-Wire Distribution Systems Using a Dual Control Strategy

Abstract: This paper presents the study, analysis, and practical implementation of a versatile unified power quality conditioner (UPQC), which can be connected in both three-phase three-wire (3P3W) or three-phase four-wire distribution systems for performing the series–parallel power-line conditioning. Thus, even when only a 3P3W power system is available at a plant site, the UPQC is able to carry out power-line compensation for installed loads that require a neutral conductor to operate. Different from the control strategies used in the most of UPQC applications in which the controlled quantities are nonsinusoidal, this UPQC employs a dual compensation strategy such that the controlled quantities are always sinusoidal. Thereby, the series converter is controlled to act as a sinusoidal current source, whereas the parallel converter operates as a sinusoidal voltage source. Thus, because the controlled quantities are sinusoidal, it is possible to reduce the complexity of the algorithms used to calculate the compensation references. Therefore, since the voltage and current controllers are implemented into the synchronous reference frame, their control references are continuous, decreasing the steady-state errors when traditional proportional–integral controllers are employed. Static and dynamic performances, as well as the effectiveness, of the dual UPQC are evaluated by means of experimental results.