This paper provides two options for the design of the Proportional + Integral (PI) controller for the DC-link voltage loop, which is found in several topologies, such as AC/DC voltage source converters and Back-to-Back converters among others. The proposed methods are based in the bandwidth approach. For the design of the DC-link voltage loop, the Back-to-Back topology is used and two cases the studies are analyzed. In the first case the converter controls the power transfer between the mains and the load; in the second it controls the active and reactive power as a PWM Rectifier with active filter function (PWM-VSR-C). In both cases the dq reference frame is used for the design of the controllers. The proposed methods are practical and clearly explained. The designs are validated with simulations and experimental results.

This paper studies the performance of the Back-to-Back (BTB) power converter based on Voltage Source Converters (VSC) for the management of the bidirectional transference of active power between two interconnected AC systems (the power supply and the load); as well as the bidirectional reactive power (for either generate and/or absorb) in both terminals of the AC interconnected systems. For power flow management two control laws are explored based on the theory of linear and nonlinear control. The nonlinear control is developed based on the feedback linearization approach. Through the two control laws is possible to obtain a decoupled model of the current components (active and reactive) in the dq synchronous reference frame. The power flow control is achieved by independently controlling the active and reactive components of the current. The control scheme includes two cascade loops (nested), for regulating DC-link voltage, as well as active and reactive power; this control scheme is typically used for VSC control, since it allows increasing the control objectives. The performance of the BTB converter for power flow control is demonstrated through simulation and experimental results using a 3kVA BTB power converter.

Nowadays, the use of power converters to control active and reactive power in AC–AC grid-connected systems has increased. With respect to indirect AC–AC converters, the tendency is to enable the back-to-back (BTB) voltage source converter (VSC) as an active power filter (APF) to compensate current harmonics. Most of the reported works use the BTB-VSC as an auxiliary topology that, combined with other topologies, is capable of active power regulation, reactive power compensation and current harmonic filtering. With the analysis presented in this work, the framework of the dynamics associated with the control loops is established and it is demonstrated that BTB-VSC can perform the three tasks for which, in the reviewed literature, at least two different topologies are reported. The proposed analysis works to support the performance criteria of the BTB-VSC when it executes the three control actions simultaneously and the total current harmonic distortion is reduced from 27.21% to 6.16% with the selected control strategy.

This paper describes the design of an AC–AC converter capable of generating a high-quality output. It is based on the Cuk configuration, with the transistors replaced by bidirectional switches. Since there are no transformers in the configuration, the converter lends itself to a compact and lightweight implementation. The design process is aimed at using, as much as possible, the tools and devices already developed for DC–DC applications. This approach greatly simplifies the design and implementation of the converter. An integrated circuit, developed for DC–DC applications, is used to control the converter. Both the set-point and the feedback signal are rectified in order to fit the input range of the controller. Tests performed show that the output exhibits a maximum total harmonic distortion of 3% (resistive load). The efficiency is slightly higher than 89%, and the average output regulation is 0.3%. The converter is capable of correcting voltage sags down to 60% and voltage swells up to 30%, with the output returning to its nominal value within one mains cycle. The results show that the converter is suitable for energizing information-processing equipment.

This paper presents two control strategies for a Single-Phase Back-to-Back (SPBTB) converter for control bidirectional power transfer based on the linear operating region of the topology. The control strategies presented allow an independent control of active/reactive power. The first scheme proposes to cancel the non-linear expressions associated to the linearized model. Therefore, it is obtained a suitable steady state and dynamic response of the system. The second control strategy uses a non-linear method that ensures a better response, since it does not linearize around a specific point, obtaining a global control law for the all operating region. The performance is verified with simulation and experimental results.