Showing papers on "Maximum power point tracking published in 2003"
TL;DR: It is found that the P&O method, when properly optimized, can have MPPT efficiencies well in excess of 97%, and is highly competitive against other MPPT algorithms.
Abstract: Maximum power point trackers (MPPTs) play an important role in photovoltaic (PV) power systems because they maximize the power output from a PV system for a given set of conditions, and therefore maximize the array efficiency. Thus, an MPPT can minimize the overall system cost. MPPTs find and maintain operation at the maximum power point, using an MPPT algorithm. Many such algorithms have been proposed. However, one particular algorithm, the perturb-and-observe (P&O) method, claimed by many in the literature to be inferior to others, continues to be by far the most widely used method in commercial PV MPPTs. Part of the reason for this is that the published comparisons between methods do not include an experimental comparison between multiple algorithms with all algorithms optimized and a standardized MPPT hardware. This paper provides such a comparison. MPPT algorithm performance is quantified through the MPPT efficiency. In this work, results are obtained for three optimized algorithms, using a microprocessor-controlled MPPT operating from a PV array and also a PV array simulator. It is found that the P&O method, when properly optimized, can have MPPT efficiencies well in excess of 97%, and is highly competitive against other MPPT algorithms. Copyright © 2002 John Wiley & Sons, Ltd.
866 citations
TL;DR: In this paper, a feedforward MP-point tracking scheme is developed for the coupled-inductor interleaved-boost-converter-fed PV system using a fuzzy controller that results in better tracking performance.
Abstract: The photovoltaic (PV) generator exhibits a nonlinear V-I characteristic and its maximum power (MP) point varies with solar insolation. In this paper, a feedforward MP-point tracking scheme is developed for the coupled-inductor interleaved-boost-converter-fed PV system using a fuzzy controller. The proposed converter has lower switch current stress and improved efficiency over the noncoupled converter system. For a given solar insolation, the tracking algorithm changes the duty ratio of the converter such that the solar cell array voltage equals the voltage corresponding to the MP point. This is done by the feedforward loop, which generates an error signal by comparing the instantaneous array voltage and reference voltage corresponding to the MP point. Depending on the error and change of error signals, the fuzzy controller generates a control signal for the pulsewidth-modulation generator which in turn adjusts the duty ratio of the converter. The reference voltage corresponding to the MP point for the feedforward loop is obtained by an offline trained neural network. Experimental data are used for offline training of the neural network, which employs a backpropagation algorithm. The proposed peak power tracking effectiveness is demonstrated through simulation and experimental results. Tracking performance of the proposed controller is also compared with the conventional proportional-plus-integral-controller-based system. These studies reveal that the fuzzy controller results in better tracking performance.
477 citations
23 Jun 2003
TL;DR: In this paper, the authors present an overview on recent developments and a summary of the state-of-the-art in inverter technology for single-phase grid connected photovoltaic (PV) systems.
Abstract: This work presents an overview on recent developments and a summary of the state-of-the-art in inverter technology for single-phase grid connected photovoltaic (PV) systems. The information provided includes details on commercially available European string and module integrated PV inverters, their efficiency, price trends and market share. This review is given for inverters for a power level up to 6 kW. Furthermore, the paper deals with the recent developments of new inverter topologies and PV system concepts and discusses possible future trends.
447 citations
TL;DR: In this paper, the effect of wind power on power system oscillations is investigated by gradually replacing the power generated by the synchronous generators in the system by power from either constant or variable speed wind turbines, while observing the movement of the eigenvalues through the complex plane.
392 citations
TL;DR: In this article, the authors proposed a photovoltaic inverter system composed of a half-bridge inverter at the utility interface and a novel generation control circuit which compensates for reductions in the output power of the system that are attributable to variations in the generation conditions of respective PV modules.
Abstract: This paper presents a novel photovoltaic inverter that cannot only synchronize a sinusoidal AC output current with a utility line voltage, but also control the power generation of each photovoltaic module in an array. The proposed inverter system is composed of a half-bridge inverter at the utility interface and a novel generation control circuit which compensates for reductions in the output power of the system that are attributable to variations in the generation conditions of respective photovoltaic modules. The generation control circuit allows each photovoltaic module to operate independently at peak capacity, simply by detecting the output power of the system. Furthermore, the generation control circuit attenuates low-frequency ripple voltage, which is caused by the half-bridge inverter, across the photovoltaic modules. Consequently, the output power of the system is increased due to the increase in average power generated by the photovoltaic modules. The effectiveness of the proposed inverter system is confirmed experimentally and by means of simulation.
383 citations
12 Oct 2003
TL;DR: The proposed output maximization control is achieved without mechanical sensors such as wind speed sensor and position sensor, and several experimental results show the effectiveness of the proposed wind generation system.
Abstract: This paper proposes a variable-speed wind generation system using an interior permanent-magnet synchronous generator (IPMSG). The armature current vector of the IPMSG is optimally controlled according to the generator speed in order to maximize the generated power from the wind turbine. The IPMSG is controlled by the loss-minimization control with maximum power point tracking below the base speed, which corresponds to low and medium wind speed, and the maximum energy can be captured from the wind. Above the base speed corresponding to the high wind speed region, the current- and voltage-limited maximum output control is applied, where the current vector is optimally controlled so that the output may become the maximum in consideration of the constraints of current and voltage. The proposed output maximization control is achieved without mechanical sensors such as wind speed sensor and position sensor. The control system has been developed and several experimental results show the effectiveness of the proposed wind generation system.
362 citations
13 Jul 2003
TL;DR: In this paper, a two-stage MPPT control method is proposed to realize a relatively simple control system which can track the real maximum power point even under nonuniform insolation conditions.
Abstract: A photovoltaic (PV) array shows relatively low output power density, and has a greatly drooping current-voltage (I-V) characteristic. Therefore, maximum power point tracking (MPPT) control is used to maximize the output power of the PV array. Many papers have been reported in relation to MPPT. However, the current-power (I-P) curve sometimes shows multilocal maximum points mode under nonuniform insolation conditions. The operating point of the PV system tends to converge to a local maximum output point which is not the real maximal output point on the I-P curve. Some papers have been also reported, trying to avoid this difficulty. However most of those control systems become rather complicated. Then, the two stage MPPT control method is proposed in this paper to realize a relatively simple control system which can track the real maximum power point even under nonuniform insolation conditions. The feasibility of this control concept is confirmed for steady insolation as well as for rapidly changing insolation by simulation study using software PSIM and Lab VIEW.
296 citations
15 Jun 2003
TL;DR: In this paper, a new control method and proportional PWM modulation of the cascaded H-bridge multilevel converter for grid-connected photovoltaic systems is introduced.
Abstract: This paper introduces a new control method and proportional PWM modulation of the cascaded H-bridge multilevel converter for grid-connected photovoltaic systems. This control makes each H-bridge module supply different power levels, allowing therefore for each module an independent maximum power point tracking of the corresponding photovoltaic array.
270 citations
01 Jun 2003
TL;DR: In this paper, a multilevel inverter is introduced which is created by cascading two three-phase three-level inverters using the load connection, but requires only one dc voltage source.
Abstract: A new type of multilevel inverter is introduced which is created by cascading two three-phase three-level inverters using the load connection, but requires only one dc voltage source. This new inverter can operate as a seven-level inverter and naturally splits the power conversion into a higher-voltage lower-frequency inverter and a lower-voltage higher-frequency inverter. This type of system presents particular advantages to Naval ship propulsion systems which rely on high power quality, survivable drives. New control methods are described involving both joint and separate control of the individual three-level inverters. Simulation results demonstrate the effectiveness of both controls. A laboratory set-up at the Naval Surface Warfare Center power electronics laboratory was used to validate the proposed joint-inverter control. Due to the effect of compounding levels in the cascaded inverter, a high number of levels are available resulting in a voltage THD of 9% (without filtering).
253 citations
15 Jun 2003
TL;DR: In this paper, a modified version of the inverter proposed by Shimizu et al. solves a major problem within the original topology; regeneration of transformer leakage energy, and a decomposition of the currents and voltages inside the inverters is used to derive the stress and power losses.
Abstract: The objective for this paper is to present a novel inverter topology for photovoltaic (PV) applications, in particular for the AC-module. A modified version of the inverter proposed by Shimizu et al. solves a major problem within the original topology; regeneration of transformer leakage energy. Also presented is a decomposition of the currents and voltages inside the inverter. The decomposition is used to derive the stress and power losses, and hereby developing a tool for optimizing the inverter in terms of efficiency and ratings. Finally, the developed tool is used to design an inverter. The annual European efficiency is calculated to 81.8% for a 160 W inverter, which is regarded as high for an inverter for AC-module applications, as long the cost can be kept low.
251 citations
Patent•
21 Apr 2003
TL;DR: In this article, a multi-mode renewable power converter system is presented, which includes a control unit, a boost converter, an inverter, and an optional bi-directional charger, where the boost converter converts DC output of a solar cell or a renewable source to high DC bus voltage, and the inverter converts this voltage to an AC output.
Abstract: A multi-mode renewable power converter system is disclosed. The system includes a control unit, a boost converter, an inverter and optional bi-directional charger, wherein the boost converter converts DC output of a solar cell or a renewable source to high DC bus voltage, and the inverter converts this DC bus voltage to an AC output. This power converter can be used to support standalone load or grid-connected system with a dynamic maximum power point tracking (MPPT) circuit. The MPPT circuit detects the current and voltage from the solar cell and indicates to the inverter to provide power to the load connected. When the optional bi-directional charger is installed, the MPPT signal is also fed to this charger to make the power efficiency maximized for the system.
TL;DR: In this paper, a novel technique for efficiently extracting the maximum output power from a solar panel under varying meteorological conditions is presented, which is based on connecting a pulsewidth-modulated (PWM) DC/DC SEPIC or Cuk converter between the solar panel and a load or battery bus.
Abstract: A novel technique for efficiently extracting the maximum output power from a solar panel under varying meteorological conditions is presented. The methodology is based on connecting a pulse-width-modulated (PWM) DC/DC SEPIC or Cuk converter between a solar panel and a load or battery bus. The converter operates in discontinuous capacitor voltage mode whilst its input current is continuous. By modulating a small-signal sinusoidal perturbation into the duty cycle of the main switch and comparing the maximum variation in the input voltage and the voltage stress of the main switch, the maximum power point (MPP) of the panel can be located. The nominal duty cycle of the main switch in the converter is adjusted to a value, so that the input resistance of the converter is equal to the equivalent output resistance of the solar panel at the MPP. This approach ensures maximum power transfer under all conditions without using microprocessors for calculation. Detailed mathematical derivations of the MPP tracking technique are included. The tracking capability of the proposed technique has been verified experimentally with a 10-W solar panel at different insolation (incident solar radiation) levels and under large-signal insolation level changes.
19 Feb 2003
TL;DR: In this article, a DSP-based improved maximum power point tracking (MPPT) approach for multiple solar array application is presented, which incorporates a "shared bus" current sharing method that can regulate many paralleled current mode DC/DC converters.
Abstract: A DSP-based improved maximum power point tracking (MPPT) approach for multiple solar array application is presented. It incorporates a "shared bus" current sharing method that can regulate many paralleled current mode DC/DC converters. The modular architecture eases the expansion of system power. The current sharing and MPPT performance of the proposed system is validated and evaluated by a 500 W prototype with two solar arrays.
TL;DR: In this article, an efficient cost-effective batteryless photovoltaic-powered seawater reverse-osmosis desalination system is described, which employs standard industrial inverters, motors and pumps, which offer excellent energy and cost efficiency.
Patent•
22 Sep 2003
TL;DR: In this paper, a grid-connected power system includes a primary power source, a back-up power source and a DC/AC inverter, where the output of the inverter is supplied to a selected portion of the load when power from the utility grid is unavailable to the load.
Abstract: A grid-connected power system includes a primary power source, a back-up power source, a DC/AC inverter and a DC/DC converter. Direct current from the primary power source is supplied to the DC/AC inverter to obtain an alternating current output supplied to a utility grid when power from the utility grid is available to power a load. The output of the inverter is supplied to a selected portion of the load when power from the utility grid is unavailable to the load. Direct current from the back-up power source is supplied to the inverter through a DC/DC converter when power from the utility grid is unavailable to the load. The DC/DC converter converts the voltage of direct current from the back-up power source to direct current having a voltage compatible with the voltage of the primary power source and the inverter. The back-up power source may be charged by the primary power source or by the utility grid. Methods of providing back-up power include converting the voltage of direct current from a back-up power source to direct current of converted voltage and supplying the direct current of converted voltage to a DC/AC inverter.
Patent•
14 Nov 2003TL;DR: In this paper, a power converter system advantageously employs a modular, bi-directionally symmetrical power converter assembly in a readily customizable configuration to interconnect a direct current power source to a three-phase alternating power grid.
Abstract: A power converter system advantageously employs a modular, bi-directionally symmetrical power converter assembly in a readily customizable configuration to interconnect a direct current power source to a three-phase alternating power grid. Connections external to the power converter assembly are selected to optimize the power converter system for a specific application, such as interconnecting a photovoltaic array to the three-phase electrical power grid. The electrical interconnections of various elements including isolation transformers, voltage sensors, and control switches are optimized to improve efficiency and reliability.
Patent•
21 Feb 2003
TL;DR: In this article, the authors proposed an inverter circuit topology where the DC source is connected directly to the positive bus of the DC to AC converter and where a negative bus is generated from the negative bus with a flyback converter.
Abstract: This invention improves the performance and lowers the cost of DC to AC inverters and the systems where these inverters are used. The performance enhancements are most valuable in renewable and distributed energy applications where high power conversion efficiencies are critical. The invention allows a variety of DC sources to provide power thru the inverter to the utility grid without a transformer and at very high power conversion efficiencies. The enabling technology is a novel inverter circuit topology where the DC source is connected directly to the positive bus of the DC to AC converter and where a negative bus is generated from the positive bus with a flyback converter. The inverter power topology does include or require a transformer. The AC inverter output configuration can be either single-phase or three-phase. The AC inverter output can be either utility interactive or directly supply loads.
Patent•
22 Sep 2003TL;DR: In this article, a conditioning circuit that measures operating points of a power supply to deduce therefrom the current-voltage characteristic of the power supply and determine directly the voltage corresponding to its maximum power point, without using any kind of tracking algorithm, is presented.
Abstract: The invention relates to a conditioning circuit that measures operating points of a power supply to deduce therefrom the current-voltage characteristic thereof and to determine directly the voltage corresponding to its maximum power point, without using any kind of tracking algorithm that causes the operating point of the power unit to oscillate about the maximum power point The maximum power point voltage VMPP is supplied to a controller which regulates a power cell by slaving it to the input voltage until the output voltage of the supply is equal to the maximum power point voltage V MPP The invention also relates to a solar generator and an associated conditioning method One particular application is to high-power satellites
21 May 2003
TL;DR: In this paper, a power circuit configuration to realize three-level inversion is proposed by connecting two two-level inverters in cascade, in the proposed configuration, an isolated DC power supply is used to supply each inverter in this power circuit.
Abstract: A power circuit configuration to realise three-level inversion is proposed. Three-level inversion is realised by connecting two two-level inverters in cascade, in the proposed configuration. An isolated DC power supply is used to supply each inverter in this power circuit. Each DC-link voltage is equal to half of the DC-link voltage in a conventional NPC (neutral point clamped) three-level inverter topology. Neutral point fluctuations are absent, and fast recovery neutral clamping diodes are not needed. The proposed inverter scheme produces 64 space-vector combinations distributed over 19 space-vector locations as compared to 27 combinations in a conventional three-level topology. The present power circuit can be operated as a two-level inverter in the range of lower modulation, by clamping one inverter to a zero state and by switching the other inverter. When compared to the H-bridge topology, this circuit needs one power supply less. A space vector based PWM scheme is used for the experimental verification of the proposed topology.
TL;DR: In this paper, two approaches to the mitigation of power quality problems are discussed: load conditioning and line-conditioning, which ensure that the equipment is made less sensitive to power disturbances, allowing the operation even under significant voltage distortion.
Abstract: There are two approaches to the mitigation of power quality problems. The first approach is called load conditioning, which ensures that the equipment is made less sensitive to power disturbances, allowing the operation even under significant voltage distortion. The other solution is to install line-conditioning systems that suppress or counteract the power system disturbances. Among the different new technical options available to improve power quality, active power filters have proved to be an important and flexible alternative to compensate for current and voltage disturbances in power distribution systems. Power filter topologies are discussed including shunt active filter, series active filters, series-shunt active filters, and hybrid active filters. New topologies using multilevel inverters are also discussed.
Patent•
29 Jan 2003TL;DR: In this article, a photovoltaic inverter control method includes steps of monitoring a variation in output voltage of a solar battery by a power and voltage monitoring circuit and, when the variation occurs, accelerating or decelerating an electric motor to maximize the output voltage.
Abstract: A photovoltaic inverter control method includes steps of monitoring a variation in output voltage of a solar battery by a power and voltage monitoring circuit (51) and, when the variation occurs, accelerating or decelerating an electric motor (3) to maximize the output voltage of the solar battery (1), whereby the electric motor for driving, for example, a pump and a fan by the solar battery as a power source can be driven by a photovoltaic inverter always at the maximum power point of the solar battery.
08 Apr 2003
TL;DR: In this article, a two-cell interleaved boost converter with coupled inductors is used to match the photovoltaic system to the load and to operate the solar cell array at maximum power point.
Abstract: A photovoltaic generator exhibits nonlinear voltage-current characteristics and its maximum power point varies with solar radiation. A two-cell interleaved boost converter with coupled inductors is used to match the photovoltaic system to the load and to operate the solar cell array at maximum power point. A maximum power point tracking algorithm is developed using only load voltage information, eliminating the array current detection. The present converter system has the advantages of low ripple content, both on the load and source side, improved efficiency and reduced switch stress, as compared to noncoupled two-cell interleaved converters. As a result, a lower value of array capacitance is sufficient for smoothing the array voltage and current. Analytical expressions for the photovoltaic source and interleaved boost converter, corresponding to maximum power point operation of the SCA, are derived. Experimental results are presented to demonstrate the suitability of this converter system. Few experimental observations are also presented for partial shading conditions. Further, a comparative study of coupled and noncoupled interleaved boost converters for photovoltaic applications is made. These studies reveal that, by introducing coupling among the parallel branch inductors, it is possible to improve steady-state performance while maintaining the dynamic performance of the photovoltaic system.
19 Feb 2003
TL;DR: In this paper, an improved MPPT converter with current compensation method for small-scaled PV-applications is presented, which implements maximum power point tracking (MPPT) by variable reference current which is continuously changed during one sampling period.
Abstract: An improved MPPT converter with current compensation method for small-scaled PV-applications is presented in this paper. The proposed method implements maximum power point tracking (MPPT) by variable reference current which is continuously changed during one sampling period. Therefore, the proposed MPPT converter with current compensation method increases the power transferred to the load above 9%. As a result, the utilization efficiency of photovoltaic (PV)-module can be increased. In addition, as it doesn't use a digital signal processor (DSP), this MPPT method has the merits of both a cost efficiency and a simple control circuit design. Therefore, it is considered that the proposed MPPT method is proper to low power, low cost PV-applications. The concept and control principles of this improved MPPT method are explained in detail and the validity of the proposed method is verified through several simulated results.
19 Feb 2003
TL;DR: In this paper, a control algorithm for the inverter operating under faulty conditions is proposed to increase the fault tolerance for cascaded H-bridge multilevel inverters. But, the proposed control algorithm is suitable for use in the cascaded h-bridge inverters of any voltage levels.
Abstract: To increase the fault tolerance for cascaded H-bridge multilevel inverters, a novel control algorithm is proposed for the inverter operating under faulty conditions. The influence of various faults on space vectors is investigated and the maximum achievable output voltage of the inverter with faulty power cells is derived. Making use of the redundant switching states, the proposed algorithm is able to produce a three-phase balanced line-to-line voltage with minimum harmonic distortion for the inverter with disabled power cells. In addition, the control algorithm is suitable for use in the cascaded H-bridge inverters of any voltage levels. Simulation and experimental results are provided for verification.
Patent•
18 Dec 2003
TL;DR: In this paper, a power control interface between an unstable power source such as a wind farm and a power transmission line employs an Electrical Energy Storage, Control System, and Electronic Compensation Module which act together like an "electronic shock absorber" for storing excess power during periods of increased power generation and releasing stored energy during decreased power generation due to wind fluctuations.
Abstract: A power control interface between an unstable power source such as a wind farm and a power transmission line employs an Electrical Energy Storage, Control System, and Electronic Compensation Module which act together like an 'electronic shock absorber' for storing excess power during periods of increased power generation and releasing stored energy during periods of decreased power generation due to wind fluctuations. The Control System is provided with a 'look ahead' capability for predicting power output (wind speed conditions) and maintaining energy storage or release over a 'narrow-band' range despite short duration fluctuations. The Control System uses data derived from monitoring the wind farm power output and the power transmission line, and employs system-modeling algorithms to predict narrow-band wind speed conditions. The power control interface can also use its energy storage capacity to provide voltage support at the point of injection into the power transmission system, as well as fault clearance capability for 'riding out' transient fault conditions occurring on the power transmission line.
Proceedings Article•
01 Jan 2003
Abstract: Many grid connected PV installations consist of a single series string of PV modules and a single DC-AC inverter. This efficiency of this topology can be enhanced with additional low power, low cost per panel converter modules. Most current flows directly in the series string which ensures high efficiency. However parallel Cuk or buck-boost DC-DC converters connected across each adjacent pair of modules now support any desired current difference between series connected PV modules. Each converter “shuffles” the desired difference in PV module currents between two modules and so on up the string. Spice simulations show that even with poor efficiency, these modules can make a significant improvement to the overall power which can be recovered from partially shaded PV strings.
TL;DR: A single-phase three-wire photovoltaic energy conversion system with single-stage structure using a novel maximum power-point tracking (MPPT) algorithm is presented and an equivalent model is derived to analyze the characteristics of the system and to design the controller.
Abstract: A single-phase three-wire photovoltaic energy conversion system with single-stage structure using a novel maximum power-point tracking (MPPT) algorithm is presented. An equivalent model of the proposed system is derived to analyze the characteristics of the system and to design the controller. Owing to the linear relation of the PV array parameters versus insolation, the model is easy to analyze. The proposed system employs a three-leg inverter to control the MPPT process, the line current, and neutral line current. A current-controlled MPPT algorithm controls the MPPT. A neutral line-mode controller maintains a utility neutral line current of zero. A line-mode controller controls the line current so as to provide power to the utility with a unity power factor. The proposed system acts as a solar generator on sunny days and functions as an active power filter on rainy days. Computer simulation and experimental results demonstrate the accuracy and the superior performance of the proposed technique.
01 Jan 2003
TL;DR: The ratio between the load current and the short-circuit current of a PV panel at maximum power point is nearly constant for different insolation (light) levels and this property is utilized in designing a simplemaximum power point tracking (MPPT) controller.
Abstract: A simple power conditioner to convert the power available from solar panels for feeding into 60 Hz AC mains is described. The output from the solar panels will be converted into a regulated DC voltage using a boost converter and a large capacitor. The DC output will then be converted to 60 Hz AC using a bridge inverter. The ratio between the load current and the short-circuit current of a PV panel at maximum power point is nearly constant for different insolation (light) levels and this property is utilized in designing a simple maximum power point tracking (MPPT) controller. The results obtained on an experimental converter are presented.
TL;DR: In this paper, a single-phase three-wire (1/spl phi/ 3W) grid-connection photovoltaic (PV) power inverter with a partial active power filter (PAPF) feature is presented, which not only deal with PV power but filter current harmonics and improve power factor.
Abstract: This paper presents a single-phase three-wire (1/spl phi/ 3W) grid-connection photovoltaic (PV) power inverter with a of partial active power filter (PAPF) feature, which can not only deal with PV power but filter current harmonics and improve power factor. Once the processed power exceeds the switch ratings, the inverter can reduce its output reactive power and harmonic power, while still supplying the maximum real power generated by the PV arrays. In the derivation of control laws, a limit circle is defined to confine the output power of the inverter. To determine the power that the inverter can process, the instantaneous reactive power of a 1/spl phi/ 3W system is defined and used to calculate reactive power, which can avoid complex detections of phase angle and magnitude of the fundamental component of a nonlinear load current. Simulation results and experimental measurements have verified the proposed algorithm and the feasibility of the inverter.
25 May 2003
TL;DR: In this paper, a simple power conditioner to convert the power available from solar panels for feeding into 60 Hz AC mains is described, where the output from the solar panels will be converted into a regulated DC voltage using a boost converter and a large capacitor.
Abstract: A simple power conditioner to convert the power available from solar panels for feeding into 60 Hz AC mains is described. The output from the solar panels will be converted into a regulated DC voltage using a boost converter and a large capacitor. The DC output will then be converted to 60 Hz AC using a bridge inverter. The ratio between the load current and the short-circuit current of a PV panel at maximum power point is nearly constant for different insolation (light) levels and this property is utilized in designing a simple maximum power point tracking (MPPT) controller. The results obtained on an experimental converter are presented.