Wanchalerm Pora

Development of an automatic meter reading system based on ZigBee PRO Smart Energy Profile IEEE 802.15.4 standard

In this paper, we propose a development of an automatic meter reading system focusing on the design for an energy meter implemented with ZigBee wireless communication protocol conforming to IEEE 802.15.4 standard. We use a microcontroller STM32L152VBT6 to manage energy data and ZigBee to enable communication between the energy meter and data centers.

Development of smart meter for building energy management system based on the IEEE 1888 standard with Wi-Fi communication

This paper implements smart meter for building energy management system based on the IEEE 1888 standard with Wi-Fi communication to monitor the electricity consumption via a control center.

A SERIES DC POWER LINE COMMUNICATION AND ITS APPLICATION TO MONITORING PHOTO-VOLTAIC STRINGS

A communication circuit for transmitting and receiving signal through a series connection of photo-voltaic (PV) panels is proposed. It consists of a transformer connected in series with each panel to couple current signal in and out of the DC power line. This allows data transmission through the panels without using any additional wires or radio frequency link. A practical case of eight 40 W amorphous PV panels is used to demonstrate the design process. It is found that the optimum carrier frequency is 250 kHz at which the panel output impedance is around 5 Ohms, allowing the current signal to pass through with low energy lost. Coupling circuit consists of inductors and capacitors designed to give highest transmission at the carrier frequency. Simulation to verify the circuit performance using a non-ideal model of a toroidal transformer is carried out to prove the feasibility of the concept.

Development of a 6-axis robotic arm controller implemented on a low-cost microcontroller

This paper presents a case study of development of a 6-axis robotic arm controller. The robot is powered by a hydraulic pump. The position of each axis can be derived from its potentiometer voltage. At each and every axis, a servo-valve is employed to control a servo motor. Its relative velocity is related to the servo-valve input. With 2nd order PID controller, a micro-controller commands movements of all axes. The PID inputs are the six voltages from potentiometers and its outputs are the six DC voltages, which command the six servo-valves. A trajectory file is generated by solving the inverse kinematics problem with some (angular to digital value) conversions. A special case; closedform calculation is developed to solve kinematics problem. With some constraints it only yields one solution. Experiments show that robot follow the given trajectory with acceptable errors.

Development of Phasor Measurement Unit conformed to IEEE C37.118 standard for 50 Hz power system

Phasor is an electrical complex value containing of magnitude root mean square value and phase angle in polar form represents instantaneous electrical sinusoidal waveform. In this paper, we propose an idea to develop phasor measurement device without communication part, conformed to IEEE C37.118 standard for 50 Hz power system, powered by ARM Cortex™-M3 microcontroller.

Error analyses of a 3-phase electricity meter with class-0.5 accuracy

A design of a 3-phase TOU electricity meter with IEC687 class 0.5 accuracy is proposed. The emphasis is upon its error analyses. Current transformers and voltage dividers are chosen to be the current and voltage transducers respectively. Two T1 ADS8345 16-bit A/D converters are used to digitize 3-phase current and 3-phase voltage signals independently. The Dallas DS89C450 microcontroller processes data with 16-bit fix-pointed calculation. Experiment results show that the accuracy of the meter lies within ranges specified in the IEC687 standard. Error Analyses are compared with the measured results, and show that the main cause of error is variation of the phase shift of the CT.

A simulation of a communication between a smart meter and a data concentrator unit conformed to DLMS/COSEM upon an HDLC profile

This article describes communication between a simulated smart meter and a simulated data concentrator unit (DCU) conformed to DLMS/COSEM. The communication is based on the three-layer, HDLC-based profile. A DLMS/COSEM library was developed. The APDUs generated by the library were the same as those from examples in the standard book. Furthermore, employing this library, the data concentrator unit can read successfully commercial DLMS meters.

Inverting amplifier based ultra low power low offset current comparator

A new design of CMOS current comparator with emphasis on low input offset current and low power consumption is described. Its unique approach is the use of identical inverting amplifiers to operate as transimpedance amplifier and voltage comparator that guarantees zero input offset current independent of how the inverting amplifier is implemented. This allows the amplifier to be just a simple NMOS driving PMOS current load enable a power delay trade off by adjusting the load current. This amplifier topology can also operate at DC power supply as low as 0.75V and in subthreshold region to achieve highest gain. Simulation using 0.18μm process, 1V DC supply, and 25nA load shows that it can outperform other existed works with an input offset current of less than 1pA under all standard PVT variations.

Development of a modified perturb and observe algorithm based on the characteristic of the V-D curve and the P-V curve

This paper introduces a step size selector to enhance tracking performance of the conventional P&O algorithm. The characteristic of the V-D curve is analyzed extensively in order to develop the selector. The ideal buck-boost converter is applied in the MATLAB/Simulink simulation model. Simulation results suggest that the proposed algorithm responses to the abrupt change in solar irradiance much faster than three reference algorithms and they show that average efficiency of the PV system is increased by 6% approximately. Moreover, the oscillation of output power in steady state is reduced.