DC-Voltage, Active and Reactive Power Compensation Based on Six-Sensors and Two PID Loops Control Applied to Back-to-Back Converter

In order to meet global energy efficiency and environmental objectives, production costs of these key devices, and other similar, must be reduced. Back-to-back VSC systems are essential for wind power generation and industrial machine drivers. Sensor elimination is a viable path to achieve such goal, as long as the control is adequate and does not impair the main converter functions. This paper presents the results of an academic-industrial research work aiming at a new control technique capable of reducing the number of sensors from 13 to only 6, using a single PID feedback loop for each VSC based on the monitoring the DC-link power. This leads to an easy-to-implement control scheme which preserves all functions required by AC/DC/AC conversion systems, such as DC voltage control, active power flow, and reactive power generation in each AC port. The results obtained demonstrate the suitable performance and advantages of this timely proposed technique for medium-power Back-to-Back VSC systems. Finally, four cases of study are fully discussed and supported by simulation and experimentation through a laboratory prototype.