Frequency-locked loops are essential elements for the power converters' synchronization as they are used for parameter estimation. However, the fundamental Frequency-Locked Loop structure shows sensitivity to the presence of DC offset and harmonics in the input signal. Those disturbances are causing oscillations in the estimated grid parameters making this technique unusable in those scenarios. The enhanced Frequency-Locked Loop called DC-FLL, solved DC offset sensitivity by introducing a new loop for its estimation and rejection. This paper presents a further modification of the DC-FLL, which is resistant to the presence of harmonics, by applying a Cascade Delay Signal Cancellation. This modification is able to maintain immunity to DC offset, the heritage of the DC-FLL, and also gain immunity to harmonics due to the Cascade Delay Signal Cancellation. To evaluate performance, the experimental setup was prepared and conducted. In the experiment, a few tests were verified by using an acquisition card and the MATLAB/Simulink environment.

A generation of orthogonal signals in single-phase systems, crucial for various applications such as power converters synchronization, faces challenges in handling disturbances like DC offset and low order harmonics present in power grids. This paper presents an orthogonal signal generator based on the principles of adaptive noise canceller, offering immunity to low order harmonics and DC offset. By leveraging adaptive techniques, this novel generator surpasses traditional approaches, which lack disturbance rejection capabilities. Simulation results in MATLAB validate the performance and robustness of the proposed generator, marking a significant advancement in generating orthogonal signals for single-phase systems.

As the future electric power grid will be driven by distributed renewable energy sources, the deployment of grid-connected power converters will also grow to enable seamless grid and energy source interaction. To provide the reliable operation of these converters, the estimation of fundamental grid parameters is important. The most common estimation techniques are a phase-locked loops (PLL) and a frequency-locked loops (FLL). However, those techniques encounter challenges in conducting parameter estimation when the input signal is unbalanced due to DC-offset, harmonics, signal sags, and frequency and phase variations. This paper presents an enhanced FLL loop enriched with an additional loop for estimation and rejection of the DC-offset. Active and reactive power calculations in grid-connected microgrids by using the modified FLL loops with DC-offset rejection is a novel application introduced in this paper. Experimental verification has demonstrated that the enhanced FLL loop provides fast and reliable parameter estimation as well as stable and robust power calculations, even in the presence of a DC-offset.

Embedded systems find extensive applications in various aspects of daily life and their presence in the highly connected world of today is growing. With a large number of remote devices and sensors, there is a growing need for remote data processing. Microcontrollers, often integral components of such devices, can enable remote data manipulation through the implementation of a web server called embedded web servers. The implementation of a server on such a system poses challenges, such as limited resources, so it is crucial for the web server implementation to be compatible with the available resources. This paper focuses on the requirements for the implementation of a web server. Also, an embedded web server has been designed for specific application of monitoring air parameters. The implementation utilizes the LwIP stack and allows for remote access to measurement results within a local network. The paper will delve into the operational principles of both the web server and the entire system.

The idea of this paper is the proposal of a low-cost control device based on the concept of IoT, which will have many functionalities integrated. A large number of integrated functionalities make it possible to satisfy a large number of different users. The proposed control device solution could be used both for controlling the operation of devices and machines in industrial plants and for training engineers.

Embedded systems are widely used in different spheres of everyday life. Implementation of web server into these systems enable remote access to processed data. Web server implementation should be suitable for limited resources of these systems. In this paper, web server implementation in system for air parameter monitoring will be presented. This implementation is done using LwIP stack and enables remote access to measurement results within local network. Operation principle of web server and whole system will be discussed.

The subject of this paper is design, testing and implementation of voltage control of buck power electronics converter using programmable logic controller (PLC) which is based on Beckhoff technology. The proposed control structure is first modelled in the Matlab/Simulink software environment. The built Simulink model is then integrated and transferred to the TwinCAT 3 software which converts personal computer (PC)/laptop into the real-time PLC. This paper proposes an experimental platform consisting of the following components: laptop computer used as the PLC, Beckhoff input/output (I/O) interface, power electronics converter with gate driver module, and electronic modules for measuring and adjusting the signals between the converter and the Beckhoff PLC. In this paper, the control is implemented on the example of the buck converter. However, the proposed modular experimental platform can be used for any type of the converter. Thanks to the integration of the Matlab/Simulink and TwinCAT 3 software environments and the modularity of the platform, the proposed experimental platform is suitable for rapid prototyping of different control structures of power electronics converters, which is especially useful for educational and research purposes. The given experimental results validate excellent performances of the proposed platform.

—This paper describes the application of the programmable logic controller (PLC), which is software-implemented on the personal computer (PC), for rapid prototyping and testing of maximum power point tracking (MPPT) algorithms used in photovoltaic (PV) systems. The practical results for Perturb and Observe (P&O) MPPT algorithm, which is used to extract and maintain the maximum power from the PV modules connected to the synchronous buck converter, are given.

The goal of this article is to describe a power measuring system using the frequency-locked-loop (FLL). The FLLs have a wide variety of applications such as power converters, grid synchronization, sensorless flux estimation and control of motor drives. This nature of the FLL system allows for it to be a potentially perfect tool for power calculation. In this article, a new power calculation method has been presented. This method is based on FLL as part of phase locked loop (PLL) and has enhanced feature over classical methods for power calculation widely used in industry. The obtained results showcase the effectiveness of the proposed FLL power calculation method.

Herein the idea of leveraging Raspberry Pi as a server for the integration of an incipient network management protocol, the Network Configuration Protocol (NETCONF), within IoT systems based on YANG is presented. The practical realization of this idea requires the implementation of the NETCONF protocol together with REpresentational State Transfer web services (RESTful). Such an interesting and innovative practical realization like this opens new additional possibilities in domotics systems and these possibilities will be discussed in this paper.

Filtering of unwanted frequencies represents the main aspect of digital signal processing (DSP) in any modern communication system. The main role of the filter is to perform attenuation of certain frequencies and pass only frequencies of interest. In a DSP system, sampled or discrete-time signals are processed by digital filters using different mathematical operations. Digital filters are commonly categorized as Finite Impulse Response (FIR) and Infinite Impulse Response (IIR). This research focuses on the full VHDL implementation of digital second-order lowpass IIR filter for reducing the noisy frequencies on the FPGA board. The initial step is to determine, from continuous time domain function, the transfer function in the complex {s} domain, then map transfer function in complex {z} domain and finally calculate the difference equation in discrete-time domain of the system with adequate coefficients. Prior to the FPGA implementation, the IIR filter is tested in MATLAB using a signal with mixed frequencies and signal with randomly generated noise. The digital implementation is completed by using fixed-point binary vectors and clocked processes.

We present a realization of a didactic robot environment for robot PUMA 560 for educational and research purposes. Robot PUMA 560 is probably the mathematically best-described robot, and therefore it is frequently used for research and educational purposes. A developed control environment consists of a robot controller and teach pendant. The advantage of using a personally developed solution is its open structure, which allows various tests and measurements to be performed, and that is highly convenient for educational and research purposes. The motivation behind the design of this personal didactic robot control environment arose from a survey for students after the first Summer School on Mechatronic Systems. The student questionnaire revealed severe discrepancies between theory and practice in education. Even though the primary purpose of the new control environment for robot PUMA 560 was research, it was established that it is a viable lab resource that allows for the connection between theoretical and industrial robotics. It was used for the duration of four Summer Schools and university courses. Since then, it has been fully integrated into International Burch University’s Electrical and Electronics Engineering curriculum through several courses on the bachelor and master levels for multidisciplinary problem-based learning (PBL) projects.

In this paper we present two different, software and reconfigurable hardware, open architecture approaches to the PUMA 560 robot controller implementation, fully document them and provide the full design specification, software code and hardware description. Such solutions are necessary in today’s robotics and industry: deprecated old control units render robotic installations useless and allow no upgrades, advancements, or innovation in an inherently innovative ecosystem. For the sake of simplicity, just the first robot axis is considered. The first approach described is a PC solution with data acquisition I/O board (Humusoft MF634). This board is supported with Matlab Real-Time Windows Toolbox for real-time applications and thus whole controller was designed in Matlab environment. The second approach is a robot controller developed on field programmable gate arrays (FPGA) board. The complexity of FPGA design can be overcome by using a third party software package, such as self-developed Matlab FPGA Real Time Toolbox. In both cases, parameters of motion controller are calculated by using simulation of the PUMA 560 robot first axis motion. Simulations were conducted in Matlab/Simulink using Robotics Toolbox.