Analog Maximum Power Point Tracking Research Articles

Photovoltaic system optimization by new maximum power point tracking (MPPT) models based on analog components under harsh condition

Abstract Photovoltaic (PV) energy has become a promising energy source because the demand for electrical energy from renewable energy sources is increasing worldwide in recent decades. Due to efficiency issues, the Maximum Power Point Tracking (MPPT) has been developed to optimize the solar panel’s performance. This paper presents an MPPT model, made up of the analog component, which overcomes traditional MPPT methods’ weakness via the Perturb and observes (P&O) technique. In this case, the PV system includes a PV array, a DC/DC boost converter, a battery, and a load. The proposed method was precisely built and simulated using the Powersim, MATLAB Simulink, and SimCoupler Module. The components of the analog MPPT system were designed practically in detail. The experiment was carried out by using European Efficiency Test 50530, and the results showed the proposed model has higher efficiency over the digital MPPT technique, about 99.99% as maximum. Moreover, MPPT methods were tested under steady-state, irradiation variation, and space conditions to verify the system’s potential capability with PV module Solbian 52L.

Experimental Measurements of a Low Power CMOS Analog MPPT Power Conditioning Circuit for Energy Harvesting Applications

This paper presents the complete measured performance and characterization of a fabricated power conditioning integrated circuit for energy harvesters with on-chip maximum power point tracking (MPPT) and external energy storage. This ultra-low power circuit employs an AC/DC-to-DC converter compatible with both AC and DC voltage energy harvesters. The MPPT design follows the perturbation and observation algorithm. This MPPT is capable of tracking the maximum power point of types of energy harvesters. The circuit is implemented using the AMS CMOS 0:35 μm high voltage technology and all the circuit blocks use analog electronic techniques, with the transistors operating in the sub-threshold region, in order to obtain a minimum power consumption. This power conditioning circuit consumes less than 2 μW while featuring an input voltage range of -0:5V to -50V and a power range from 10 μW to 200mW.

A New Robust Analog Maximum Power Point Tracker for a PV Battery Charger

Maximum power point tracking (MPPT) is an inevitable part of new controller design for PV connected voltage converters used to extract energy. To simplify the implementation of the algorithm, in this paper, an analog circuit for MPPT of a PV battery charger is proposed which works in a full range condition with constant switching frequency. Besides this, a new robust controller parameter is introduced. As discussed in the paper, conventional MPPT algorithms provide PV current or voltage reference value as output controller parameter, which fast climate changes may cause system instability. Here, a new variable is defined to eliminate the problem and improve the stability of the system. To compare the presented circuit with a conventional system, perturb and observe MPPT algorithm which is well-known in PV systems is implemented on the same system. The proposed system is also compared with a recently developed current-mode system. Simulation results for both simulations are presented and compared which demonstrate performance and effectiveness of the proposed analog MPPT circuit.

A Miniaturized 0.78-mW/cm2 Autonomous Thermoelectric Energy-Harvesting Platform for Biomedical Sensors.

In order to use thermoelectric energy harvesters (TEHs) as a truly autonomous energy source for size-limited sensing applications, it is essential to improve the power conversion efficiency and energy density. This study presents a thin-film, array-based TEH with a surface area of 0.83cm2. The TEH autonomously supplies a power management IC fabricated in a 65-nm CMOS technology. The IC utilizes a single-inductor topology with integrated analog maximum power point tracking (MPPT), resulting in a 68% peak end-to-end efficiency (92% converter efficiency) and less than 20-ms MPPT. In an in-vivo test, a 645-μW regulated output power (effective 3.5 K of temperature gradient) was harvested from a rat implanted with our TEH, demonstrating true energy independence in a real environment while showing a 7.9 × improvement in regulated power density compared to the state-of-the-art. The system showed autonomous operation down to 65-mV TEH input.

Analog maximum power point tracking for spacecraft within a low earth orbit

This paper describes the implementation of a reliable maximum power point tracking design as an analog circuit for use on a satellite relying on solar power generation within low Earth orbit. The environment in which such a spacecraft system would function is evaluated. A specific maximum power point tracking algorithm is selected with regards to environmental constraints. A further increase in reliability was achieved by only using carefully selected analog components that are suitable for use within a space environment. The system was prototyped, and its power conversion performance was characterized using a custom-built measurement setup. The system successfully tracked the maximum power point through all the performed measurements. The results from the measurements suggest that the prototyped system has a nominal regulator efficiency of 88% and a nominal tracking accuracy of 96%.

A current-based simple analog MPPT circuit for PV systems

A new single pilot-sensor maximum power point tracking (MPPT) system, consisting of a buck type DC/DC converter, was developed. It is controlled by an analog-based unit. The main difference between the proposed MPPT system and other systems is that the short circuit current of the pilot-PV module in our system is used to control the DC/DC converter. The circuit of the proposed system does not utilize an expensive digital signal processor nor a microcontroller; hence, the cost and the complexity of the system are reduced.

CMOS integrated MPP tracker with analog power measurement at the PV converter input

An integrated converter controller with maximum power point (MPP) regulation in 0.35 μm CMOS for photovoltaic (PV) applications is reported. The implemented MPP tracker bases on a perturb and observe algorithm and acquires the information concerning the power flow via an analog processing circuit which is connected at the switched mode converter input respectively the output of the attached PV string of nine cells. There the solar cell current is measured via a very low-ohmic shunt resistor of 1 mΩ and analogously multiplied with the cell voltage. As output the fabricated test chip directly generates a 530 kHz PWM signal for the external switched mode converter. Measurements show that under similar conditions analog MPP tracking of the converter input power improves the robustness with respect to settling times of the power path compared to those topologies at which the power is measured at the converter output. Between 0.4 and 7.5 A photocurrent the chip achieves tracking efficiencies better than 99.5 % while the power consumption is only 750 μW and a very low chip area demand of 0.043 mm2 for the MPP tracking core is achieved.

Highly Efficient Analog Maximum Power Point Tracking (AMPPT) in a Photovoltaic System

A compact-size analog maximum power point tracking (AMPPT) technique is proposed in this paper for high power efficiency in the photovoltaic (PV) system. Combining existing MPPT approaches, we present a fast and accurate tracking performance. Here, a wide-range current multiplier, which tracks the maximum power point (MPP) in the solar power system, is implemented to detect the power slope condition of the solar panel. Experimental results show that the proposed technique can rapidly track the MPP with a high tracking accuracy of 97.3%. Furthermore, the proposed system can connect to the grid-connected inverter to supply ac power.

Analog Control Algorithm for Maximum Power Trackers Employed in Photovoltaic Applications

Tracking the Maximum Power Point (MPP) of a photovoltaic (PV) array is usually an essential part of a PV system. The problem addressed by Maximum Power Point Tracking (MPPT) techniques is to find the voltage <TEX>$V_{MPP}$</TEX> or current <TEX>$I_{MPP}$</TEX> at which a PV array should operate to generate the maximum power output <TEX>$P_{MPP}$</TEX> under a given temperature and irradiance. MPPT control methods such as the perturb and observe method and the incremental conductance method require a microprocessor or DSP to determine if the duty cycle should be increased or not. This paper proposes a simple and fast analog MPPT method. The proposed control scheme tracks the MPP very quickly and its hardware implementation is simple when compared with the conventional techniques. The new algorithm can successfully track the MPP even in the case of rapidly changing atmospheric conditions. In addition, it has higher efficiency than ordinary algorithms.

Maximum Power Point Tracking Controller for Thermoelectric Generators with Peak Gain Control of Boost DC–DC Converters

An analog maximum power point tracking (MPPT) circuit for a thermoelectric generator (TEG) is proposed. We show that the peak point of the voltage conversion gain of a boost DC–DC converter with an input voltage source having an internal resistor is the maximum power point of the TEG. The key characteristic of the proposed MPPT controller is that the duty ratio of the input clock pulse to the boost DC–DC converter shifts toward the maximum power point of the TEG by seeking the peak gain point of the boost DC–DC converters. The proposed MPPT technique provides a simple and useful analog MPPT solution, without employing digital microcontroller units.

Design, realization and optimization of a photovoltaic system equipped with analog maximum power point tracking (MPPT) command and detection circuit of the dysfunction and convergence the system (CDCS)

In this paper, we analyze the design, realization and optimization of a photovoltaic (PV) system equipped with a maximum power point tracking (MPPT) command and detection circuit of dysfunction and convergence the system (CDCS) to the new maximum power point (MPP) following a perturbation due to the meteorological variation (solar radiation, temperature, ..) and the load. We have analyzed in depth manner the structure and optimization the operation of the MPPT command realized during this work. The results obtained show very good agreement between simulation and experiment. The experimental system realized during cloudy days or by varying the load, shows that it operates under optimum conditions independently of the meteorological variations. At each perturbation, the CDCS circuit detects it and convergences the system without restart it. The good efficiency of the direct current to direct current (DC-DC) converter used and the low loss (less than 7%) shows that the system realized can be used in a PV system to minimize losses due to connecting the panels to the load and in particularly to minimize the cost of installations. Key words: Panels and photovoltaic system, photovoltaic conversion, maximum power point tracking (MPPT) command, the detection circuit of dysfunction and convergence (CDCS), direct current to direct current (DC-DC) converter, simulator Pspice, optimal functioning, energy losses.

A fast and low cost analog maximum power point tracking method for low power photovoltaic systems

Abstract Low power photovoltaic (PV) systems are commonly used in stand-alone applications. For these systems, a simple and cost-effective maximum power point tracking (MPPT) solution is essential. In this paper, a fast and low cost analog MPPT method for low power PV systems is proposed. By using two voltage approximation lines (VALs) to approximate the maximum power point (MPP) locus, a low-complexity analog MPPT circuit can be developed. Theoretical derivation and detailed design procedure will be provided in this paper. The proposed method boasts the advantages such as simple structure, low cost, fast tracking speed and high tracking efficiency. To validate the correctness of the proposed method, simulation and experimental results of an 87 W PV system will also be provided to demonstrate the effectiveness of the proposed technique.

A Digital Coreless Maximum Power Point Tracking Circuit for Thermoelectric Generators

This paper describes a maximum power point tracking (MPPT) circuit for thermoelectric generators (TEG) without a digital controller unit. The proposed method uses an analog tracking circuit that samples the half point of the open-circuit voltage without a digital signal processor (DSP) or microcontroller unit for calculating the peak power point using iterative methods. The simulation results revealed that the MPPT circuit, which employs a boost-cascaded-with-buck converter, handled rapid variation of temperature and abrupt changes of load current; this method enables stable operation with high power transfer efficiency. The proposed MPPT technique is a useful analog MPPT solution for thermoelectric generators.

A new analog MPPT technique: TEODI

AbstractA new analog maximum power point tracking (MPPT) technique is presented and discussed. Its main advantages are simplicity of implementation, absence of memory and multiplication operations, and the high MPPT efficiency obtainable under both stationary and time‐varying atmospheric conditions. A numerical analysis, carried out by using the Perturb and Observe MPPT technique as a benchmark reference, confirms the validity of the proposed approach. Copyright © 2009 John Wiley &amp; Sons, Ltd.