Control algorithms based on the active and non-active currents for a UPQC without series transformers

• Autor(a) principal: Correa Monteiro, Luis Fernando
• Data de Publicação: 2016
• Outros Autores: Aredes, Mauricio, Pinto, J. G., Exposto, Bruno, Afonso, João L.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/53003
• topic: electric current control; power supply quality; power convertors; phase locked loops; power system harmonics; power factor correction; load regulation; voltage control; power system control; digital control; digital signal processing chips; nonactive current; active current; UPQC; series transformer; unified power quality conditioner; series converter; power supply; voltage imbalance; nonsinusoidal voltage-and current condition; phase-locked-loop circuit; harmonic component compensation; power factor correction; load voltage regulation; electrical power system; DSP digital control architecture; Science & Technology

This study presents control algorithms for a new unified power quality conditioner (UPQC) without the series transformers that are frequently used to make the insertion of the series converter of the UPQC between the power supply and the load. The behaviour of the proposed UPQC is evaluated in presence of voltage imbalances, as well as under non-sinusoidal voltage-and current conditions. The presented algorithms derive from the concepts involving the active and non-active currents, together with a phase-locked-loop circuit. Based on these real-time algorithms, and considering the proposed hardware topology, the UPQC is able to compensate the harmonic components of the voltages and currents, correct the power factor, and keep the load voltages regulated, all of this in a dynamic way, responding instantaneously to changes in the loads or in the electrical power system. The control algorithms were distributed in a two-DSP digital control architecture, without any communication between them. Consequently, can be increased the sampling frequency of the acquired voltages and currents and improve the UPQC performance. Furthermore, some constraints of the proposed UPQC are evidenced, particularly when the main voltages are imbalanced. Simulation and experimental results are presented to verify the UPQC performance under transient and steady state conditions.