Design and Implementation of Novel Multi-Converter-Based Unified Power Quality Conditioner for Low-Voltage High-Current Distribution System

Abstract

This paper introduces a novel multi-converter-based unified power quality conditioner (MCB-UPQC). Three optimization methods are proposed based on the traditional UPQC: (1) The shunt converter is substituted with multi-modular parallel converters. Hence, the reactive power and harmonic currents can be increased greatly, which are suitable for low-voltage high-current distribution systems. (2) The series converters consist of three H-bridge inverters, and each of the H-bridge inverters is controlled separately. The control strategy is easier to achieve and can improve the control performance of voltage regulation under unbalanced voltage sag or swell. (3) A three-phase four-leg (3P4L) converter is connected to the common DC bus of the proposed UPQC to connect the renewable energy and energy storage system. The detailed mathematical models of shunt and series converters are analyzed, respectively. A multi-proportional resonant (PR) controller is presented in the voltage regulation and reactive power compensation control algorithms. The simulation results verify the feasibility of the control algorithms. Finally, the experimental platform is established, and the experimental results are presented to verify the validity and superiority of the proposed topology and algorithms.

An Overview on Power Quality Issues and Control Strategies for Distribution Networks With the Presence of Distributed Generation Resources

“…To maintain voltage levels, a boosting transformer is connected between the series converter and the transmission system. IUPQC can function as a smart circuit breaker and power flow controller between grid and microgrid to repay the series converter's active and reactive power references [83] and [84].…”

“…Fig. 7 shows an example of UPQC-MC structure [84]. The UPQC-MC system has the ability to compensate voltage and current fluctuations in a multi-feeder system by active power sharing.…”

A Lyapunov function theory‐based nonlinear control strategy for NPC ‐type three‐level unified power quality conditioner

“…Considering that the voltage response of the out-loop is faster than that of the inner-loop, assuming U DC1 = U DC2 , which is e 5 = e 6 , y 5 = y 6 , the following equation can be obtained by substituting Equation (17) into Equation (15):…”

“…Methods employing linear model based PI control, PR control, and repetitive control among others have been widely used. [16][17][18][19] In addition to problems with parameter adjustment, these classical closed-loop feedback controllers are susceptible to external perturbation and ignore the mathematical model of a controlled system, which causes poor dynamic performance of UPQC under multiple operating conditions. Numerous nonlinear control strategies have been proposed to enhance the UPQC performance.…”

One Cycle Control of A PWM Rectifier a New Approach

“…One-Cycle control provides low complexity and low-cost implementation, disturbance rejection, robustness, good stability, and fast dynamic response. OCC has been mostly utilized in the literature to control power factor correction, and it has been applied in modular multilevel converters [2], a grid-tied single-stage buck-boost DC-AC micro-inverter [3] and Vienna Rectifiers [4], a novel multi-converter-based unified power quality conditioner (MCB-UPQC) [5]. The study and analysis of harmonics, energy consumption, and power quality of light-emitting diode (LED) lamps equipped in building lighting systems [6].…”