A smart voltage and current monitoring system for three phase inverters using an android smartphone application

In this paper, a new smart voltage and current monitoring system (SVCMS) technique is proposed. It monitors a three phase electrical system using an Arduino platform as a microcontroller to read the voltage and current from sensors and then wirelessly send the measured data to monitor the results using a new Android application. The integrated SVCMS design uses an Arduino Nano V3.0 as the microcontroller to measure the results from three voltage and three current sensors and then send this data, after calculation, to the Android smartphone device of an end user using Bluetooth HC-05. The Arduino Nano V3.0 controller and Bluetooth HC-05 are a cheap microcontroller and wireless device, respectively. The new Android smartphone application that monitors the voltage and current measurements uses the open source MIT App Inventor 2 software. It allows for monitoring some elementary fundamental voltage power quality properties. An effort has been made to investigate what is possible using available off-the-shelf components and open source software

A new synchronization technique of a three-phase grid tied inverter for photovoltaic applications

Three-phase grid synchronization is one of the main techniques of the three-phase grid connected power inverters used in photovoltaic systems. This technique was used to reach the fast and accurate three-phase grid tied inverter synchronization. In this paper a new synchronization method is presented on the basis of integrating the grid voltage two times (line-to-line or phase voltage). This method can be called “double integral synchronization method” (DISM) as it integrates the grid voltage signals two times to generate the reference signals of three-phase photovoltaic inverter currents. DISM is designed and simulated in this paper to operate in both analog and digital circuits of three-phase photovoltaic inverter system with the same topology. The digital circuit design and dsPIC33FJ256GP710A as a microcontroller (the dsPIC33FJ256GP710A with the Explorer 16 Development Board from microchip) was used practically in this paper to generate and control the sine pulse width modulation (SPWM) technique according to DISM for three-phase photovoltaic inverter system. The main advantage for this method (DISM) is learning how to eliminate the integration constant to generate the reference signals without needing any reference signals or truth table, just the line-to-line or phase voltage of grid

New pulse width modulation technique to reduce losses for three-phase photovoltaic inverters

Nowadays, most three-phase, “of the shelf” inverters use electrolytic capacitors at the DC bus to provide short term energy storage. However, this has a direct impact on inverter lifetime and the total cost of the photovoltaic system. Tis article proposes a novel control strategy called a 120∘ bus clamped PWM (120BCM). Te 120BCM modulates the DC bus and uses a smaller DC bus capacitor value, which is typical for flm capacitors. Hence, the inverter lifetime can be increased up to the operational lifetime of the photovoltaic panels. Tus, the total cost of ownership of the PV system will decrease signifcantly. Furthermore, the proposed 120BCM control strategy modulates only one phase current at a time by using only one leg to perform the modulation. As a result, switching losses are signifcantly reduced. Te full system setup is designed and presented in this paper with some practical result

An Android smart application for an Arduino based local meteorological data recording

The Meteorological conditions could be with high importance for many applications. Even this information is available in many media resources, but they are not measured for a certain position. In this paper, authors present design for a private weather station that can be established in any place. The design mainly based on a group of sensors used for supplying the information of temperature, humidity, and air speed. An Arduino Uno microcontroller is utilized to process the incoming sensing data and send them via wireless Bluetooth module to mobile phones. The mobile phones are equipped with an Android smart application to display this data. This low-cost design offers an online weather information for any local projects that need such data

A smart distance power electronic measurement using smartphone applications

The objectives of this article were to design a low-cost three-phase AC voltage measurement circuit and new Android smartphone application to monitor the measuring voltage from a safe distance. The smart distance power electronic measurement (SDPEM) system was designed based on an Arduino UNO R3 board used as a microcontroller to read and calculate the RMS values from a three-phase AC voltage measurement circuit (line-to-line or phase voltage of grid). Following this, the microcontroller sends the measuring data by Bluetooth to an Android smartphone application. The Bluetooth shield V2.0 was used as a wireless communication instrument between the SDPEM and the smartphone or tablet application. The smartphone monitoring application was a new application designed by the open-source developed program (MIT App Inventor 2) to monitor the three-phase AC voltage results from a safe distance. The safe distance depends on the type of Bluetooth device used. The main advantages of the SDPEM system are low cost and safety

Battery storage integration in voltage unbalance and overvoltage mitigation control strategies and its impact on the power quality

The increased utilisation of distributed renewable energy sources in low voltage grids leads to power quality problems such as overvoltages and voltage unbalance. This imposes challenges to the distribution system operators to maintain the power quality in their grids. To overcome these issues, energy storage systems could be integrated together with the distributed energy resources and the stored energy could be used when needed to better improve power quality and achieve better grid performance. However, integrating an energy storage system introduces additional cost, therefore, determining the right capacity is essential. In this article, an energy storage system is combined with the classical positive-sequence control strategy and the three-phase damping control strategy. The three-phase damping control strategy is able to mitigate the voltage unbalance by emulating a resistive behaviour towards the zero- and negative-sequence voltage components. This resistive behaviour can be set on different values such that the desired voltage unbalance mitigation is achieved. Hence, the three-phase damping control strategy, equipped with the energy storage system is investigated under different values of the resistive behaviour. Both control strategies are investigated under the same conditions and the impact of the different capacities of the energy storage systems is investigated

Frequency synchronization of a single-phase grid-connected DC/AC inverter using a double integration method

Many traditional grids have started to integrate the DC/AC inverters in their networks. This requires a good control to enhance the power quality. The grid frequency behaviour is one of the principal indicators that reveal the power quality. Therefore, it must be strongly controlled. Up to now, the most popular frequency synchronization method is based on phase-locked loop (PLL) control. It is known that setting a current proportional to voltage does not work well and it creates a negative resistor in a wide frequency range because the circuit is not passive. This paper presents an alternative idea of synchronization of a single-phase grid-connected DC/AC inverter by using a double integration method. It is simpler than PLL since it needs neither a phase comparator, nor a local oscillator. It provides a signal in phase with the current. The art of the method is how to remove the integrating constants without degrading the signal

PID control of a three phase photovoltaic inverter tied to a grid based on a 120-degree bus Clamp PWM

This paper presents a new operating type of a three phase photovoltaic PID current control system connected to the low voltage distribution grid. This operating type introduces a 120-degree bus clamp PWM control method (120° BC-PWM). A 120° BC-PWM is a special switching sequences technique employing bus clamp sequences that use only one phase under a PWM and PID control state every 60° while the other phases are being clamped. The BC-PWM method was used to generate six PWM signals to control a three phase inverter system every 60° with constant power input and a small dc link film capacitor. The main objective of this paper is to use new PWM techniques with a PID current control method to reduce the switching losses of three phase inverters. The losses were reduced to 1/3th for each transistor by reducing the time operation for each transistor. The simulation results of the BC-PWM method show an improvement in the performance of the three phase inverter system connected to the grid. Simulation setup of the system obtained is built by using a SiC MOSFET, 5 kVA, 400 V line-line and 25 kHz switching frequency. The PID control is not continuously active for each phase but is operational in 60° and saturated at 120° in a half period. Following a proper tuning of the windup, it recovers very easily