Three-phase

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

Novel three-phase asymmetrical cascaded multilevel voltage source inverter

Abstract: Series connection of power cells in asymmetrical cascaded configurations helps to cancel redundant output levels and maximise the number of different levels generated by the inverter. A new configuration of three-phase multilevel asymmetrical cascaded voltage source inverter is presented. This structure consists of series-connected sub-multilevel inverters blocks. The number of utilised switches, insulated gate driver circuits, voltage standing on switches, installation area and cost are considerably reduced. Cascaded-cell DC voltages in each inverter leg form an arithmetic sequence with common difference of E. With the selected inverter DC sources, high-frequency pulse-width modulation (PWM) control methods can be effectively applied without loss of modularity. Low-frequency and sinusoidal PWM techniques were successfully applied. Hence, high flexibility in the modulation of the proposed inverter is demonstrated. The prototype of the suggested inverter was manufactured and the obtained simulation and hardware results ensured the feasibility of the configuration, and the compatibility of both modulation techniques was accurately noted. Lastly, the semiconductor losses in the converter were calculated using simulation models. Based on the analysis of the total power losses, the proposed inverter provided high efficiency at different operating conditions.

System and method of electrically interconnecting multiple lighting fixtures

Abstract: A system and method of electrically interconnecting a multiplicity of electrical lighting fixtures is disclosed in which up to three phase AC power and up to five conductors (i.e., one conductor for each phase, a ground conductor, and a neutral conductor) is used in such manner that selected groups or branches of the lighting fixtures may be independently, selectively controlled, and such that wiring to the fixtures and control switches may be readily plugged into place.

A novel nine-switch PWM rectifier-inverter topology for three-phase UPS applications

Abstract: A novel three-phase PWM rectifier-inverter topology for UPS applications is proposed in this paper. The topology uses only nine IGBT devices for AC/AC conversion through a quasi DC link circuit. This converter topology features sinusoidal inputs and outputs, unity input power factor, and more importantly, low manufacturing cost. The operating principle of the converter is elaborated and a novel modulation scheme is presented. The performance of the proposed converter is verified by experiments on a 5 kVA prototyping UPS system.

Bandwidth Expansion Method for Circulating Current Control in Parallel Three-phase PWM Converter Connection System

Abstract: The use of common dc-link parallel three-phase PWM converters without isolating transformers will cause zero-sequence circulating current problem. Previous works have proven that the circulating current is mainly affected by zero vectors employed in each PWM cycle. This paper proposes a novel method to suppress the circulating current. Detailed analysis is presented on the causes of zero-sequence circulating current based on a derived average model. A zero vectors feed-forward control strategy in combination with traditional PI control method is proposed to reject disturbances in zero-axis current system. In addition, a dual current sampling and dual PWM duty ratio update (DSDU) scheme is used to expand the bandwidth of zero-axis current loop. As a result, better circulating current suppression performance can be achieved in different filter inductance and converter output currents condition. Compared with the PI control method, the converters operated in parallel can be switched on and switched off separately with small current impact. Experimental results confirm the performance and effectiveness of the proposed method.