A review of saliency-based sensorless control methods for alternating current machines

Operation of model-based sensorless control of Alternating Current machines at low and zero speeds is unreliable and can fail. To overcome the limitations of sensorless control at low speeds, several alternative techniques have been developed to estimate speed and position. These are mainly based on detecting machine saliencies by measuring the response of the current to some form of voltage injection. This paper discusses injection methods, machine saliencies, and techniques used to extract speed and position that are applicable to both induction machines and permanent magnet synchronous motors.peer-reviewe

Comparison between PI and PR current controllers in grid connected PV inverters

This paper presents a comparison between Proportional Integral (PI) and Proportional Resonant (PR) current controllers used in Grid Connected Photovoltaic (PV) Inverters. Both simulation and experimental results will be presented. A 3kW Grid- Connected PV Inverter was designed and constructed for this research.peer-reviewe

Design of PR current control with selective harmonic compensators using Matlab

This paper presents a procedure to design a Proportional Resonant (PR) current controller with additional PR selective harmonic compensators for Grid Connected Photovoltaic (PV) Inverters. The design of the PR current control and the harmonic compensators will be carried out using Matlab. Testing was carried out on a 3kW Grid- Connected PV Inverter which was designed and constructed for this research. Both simulation and experimental results will be presented.peer-reviewe

Single-phase microgrid with seamless transition capabilities between modes of operation

Microgrids are an effective way to increase the penetration of DG into the grid. They are capable of operating either in grid-connected or in islanded mode thereby increasing the supply reliability for the end user. This paper focuses on achieving seamless transitions from islanded to grid-connected and vice versa for a single phase microgrid made up from voltage controlled voltage source inverters (VC-VSIs) and current controlled voltage source inverters (CC-VSIs) working together in both modes of operation. The primary control structures for the VC-VSIs and CC-VSIs is considered together with the secondary control loops that are used to synchronize the microgrid as a single unit to the grid. Simulation results are given that show the seamless transitions between the two modes without any disconnection times for the CC-VSIs and VC-VSIs connected to the microgrid.peer-reviewe

Increasing the electric motors efficiency in industrial applications

Electric Motor Driven Systems (EMDS) account for around 65% of the electricity consumed by EU industry. Switching to energy efficient motor driven systems can save Europe 202TWh in annual electricity consumption. EMDSs are the single largest end-use of electrical energy, consuming more than twice as much as lighting, the next largest end-use. This excess energy consumption represents an unnecessary 79 million t/yr of CO2eq emissions. If CO2 emissions are reduced, it will help in today’s problems regarding climate change. By introducing several energy schemes, costs can be significantly reduced. The aim of this paper is that by conducting case studies on the Maltese manufacturing industry and carry out several experimental tests recommend certain measures to increase the electric motors’ efficiency in industrial applications.Bajada New Energy Ltd., CD Power Saving Co. Ltd., Energy Investment Co. Ltd., Solar Engineering Ltd. & Solar Solutions Ltd.peer-reviewe

Renewable energy communities in Islands : a Maltese case study

Renewable energy communities are considered as key elements for transforming the present fossil fuel-based energy systems of islands into renewable-based energy systems. This study shows how renewable energy communities can be deployed in the Maltese context to achieve higher penetration of residential-scale photovoltaic systems. Case studies for five renewable energy communities in the Maltese LV distribution network have been analyzed in detail. A novel community battery energy storage sizing strategy was proposed to determine the optimal storage capacity at each energy community. The main objective of the community battery storage in each REC is to minimize the reverse power injection in the grid (minimize the total reverse energy and reverse peak power values), as well as to reduce the peak evening electricity demand. The optimal sizes for communal BESSs were determined to be of 57 kWh (EC 1), 55 kWh (EC 2), 31 kWh (EC 3), 37 kWh (EC 4) and 10 kWh (EC 5), respectively. The community storage systems were observed to reduce the overall impact of all five energy communities on the grid infrastructure. Power system simulations were performed for a typical spring day to evaluate the impact of communal BESS placement on the node voltages for all five energy communities. The results showed that the community storage was more effective at reducing the node rms voltage magnitudes when deployed at the end of the respective energy communities, rather than at the beginning of the community. During peak generation hours, reductions of up to 0.48% in the node rms voltage magnitudes were observed. This contrasts with reductions of only 0.19% when the community storage was deployed at the beginning of the energy communities.peer-reviewe

Space modulation profile modelling for steer-by-wire SMPMSM

This paper presents a sensorless estimation algorithm for steer-by-wire applications based on the injection of a high-frequency rotating voltage. Enhancement to the basic sensorless algorithm through SMP look-up tables is proposed. The improved observer was simulated in MATLAB for a 12 V RMS 400 W permanent magnet synchronous machine (PMSM).peer-reviewe