Three-phase

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

Two-Phase Modulated Digital Control for Three-Phase Bidirectional Inverter With Wide Inductance Variation

Abstract: This paper presents two-phase modulated digital control for a three-phase bidirectional inverter with wide inductance variation in dc distribution systems. The bidirectional inverter can fulfill both grid connection and rectification with power factor correction. With the proposed control, the inverter can track its sinusoidal reference currents, and it is allowed to have wide inductance variation, reducing core size significantly. The control laws based on space-vector pulsewidth modulation are first derived with either an accurate approach or an approximated one, and the gate signals were then derived based on two-phase modulation for lower switching loss and switching noise spectra. Determination of control parameters and stability analysis are also presented. In the design and implementation, the inductances corresponding to various inductor currents were measured and tabulated into a single-chip microcontroller for tuning loop gain cycle by cycle, ensuring system stability. Measured results from a 10 kVA 3φ bidirectional inverter have been presented to confirm the feasibility of the discussed control approaches.

Apparatus for controlling three-phase AC motor on two-phase modulation technique

Abstract: An apparatus is provided to control a three-phase AC motor and comprises an inverter and a controller. The inverter powers the motor in response to a three-phase PWM command. The control circuit controls the inverter based on two modulation techniques selectively switched from one the other depending on information indicative of an operation state of the motor. One modulation technique gives the PWM command a first two-phase modulation allowing each phase voltage to be fixed at a predetermined voltage level in turn at intervals of an electrical angle of 2π/3. The other modulation technique gives the PWM command a second two-phase modulation allowing each phase voltage to be fixed at a predetermined voltage in turn at intervals of an electrical angle of π/3. The switchover can be made between the two-phase and three-phase modulations or can be made with consideration of temperature at switching elements.

Leakage Current Reduction of Three-Phase Z -Source Three-Level Four-Leg Inverter for Transformerless PV System

Abstract: Leakage current reduction is one of the important issues for transformerless photovoltaic (PV) systems. Many interesting solutions have been reported to reduce the leakage current for three-phase PV inverters. However, most of them are limited to two-level inverters. Moreover, there is a potential risk of the overcurrent phenomenon. In order to solve the problem, a Z -source three-level four-leg inverter with a new modulation strategy is proposed in this paper. First, the mathematical modeling of the three-level four-leg Z -source inverter for leakage current reduction is established for the first time. Second, a new carrier-based modulation strategy is proposed by utilizing the effective large, medium, small, and zero vectors, instead of the invalid vectors, to achieve the constant common-mode voltage, as well as the leakage current suppression. Finally, the proposed solution is carried out on the Texas Instruments TMS320F28335 DSP + Xilinx XC3400 field-programmable gate array digital control hardware platform. The experimental results verify the effectiveness of the proposed solution.

Solar PV Energy Generation System Interfaced to Three Phase Grid With Improved Power Quality

Abstract: This paper deals with a multipurpose distributed sparse (DS) control approach for a single stage solar photovoltaic (PV) energy generation system (SPEGS). This SPEGS is interfaced here to the three phase grid at varying solar irradiance and compensating the nonlinear load tied at point of common interconnection. The SPEGS performs multitasks. It feeds the generated solar PV power to the local three phase grid. It reduces the harmonics of loads and furnished balanced currents of local three-phase grid. The SPEGS uses a solar PV array, a voltage source converter (VSC), a nonlinear load, a three phase grid, and a dc-link capacitance. In case, when the solar irradiance is not available, the proposed system works as distribution static compensator by utilizing same VSC. For extracting maximum power from the PV source, the traditional perturb and observe (P&O) scheme is utilized here. The tracking performance and efficiency of P&O technique are also examined here at rapid changing climatic conditions to show the behavior of the P&O scheme. The DS control approach is capable to estimate required fundamental component to find out reference grid currents. The proposed control approach is validated on a developed prototype in the laboratory.

An improved starting strategy for voltage-source inverter fed three phase induction motor drives under inverter fault conditions

Abstract: Three phase voltage-fed inverter induction motor drives are prone to shoot through and other inverter faults that cause the drive system to shut down. The paper describes a novel strategy for restarting the drive in variable voltage variable frequency single phase mode in the presence of open base drive and shoot through fault in the inverter. The proposed method requires only the motor terminal voltages and currents to be measured. Therefore, it can be applied to even low performance open loop drives with the addition of two motor terminal voltage sensors. The starting algorithm has been verified by computer simulation and experiments on a 1 hp laboratory prototype. Experimental results are in good agreement with simulation predictions. The starting strategy described in this paper is expected to provide an economic alternative to more expensive redundancy techniques which find justification only in a few specialized applications.