Showing papers on "Maximum power point tracking published in 1994"
20 Jun 1994
TL;DR: In this article, a new maximum power point tracker (MPPT) using fuzzy set theory is proposed to improve the energy conversion efficiency of photovoltaic systems, where a fuzzy algorithm based on linguistic rules describing the operator's control strategy is applied to control the step-up converter for the MPPT.
Abstract: Studies on photovoltaic systems are increasing because of a large, secure, essentially exhaustible and broadly available resource as a future energy supply. However, the output power induced in the photovoltaic modules is influenced by an intensity of solar cell radiation, temperature of the solar cells and so on. Therefore, to maximize the efficiency of the renewable energy system, it is necessary to track the maximum power point of the input source. In this paper, a new maximum power point tracker (MPPT) using fuzzy set theory is proposed to improve energy conversion efficiency. A fuzzy algorithm based on linguistic rules describing the operator's control strategy is applied to control the step-up converter for the MPPT. Fuzzy logic control based on coarse and fine mode has been incorporated in order to reduce not only the time required to track the maximum power point but also the fluctuation of power. The MPPT algorithm is implemented by a 16 bit single chip 80C196KB microcontroller. Simulation and experimental results show that performance of the fuzzy controller in a maximum power tracking of a photovoltaic array is better than that of controller based upon the hill climbing method. >
229 citations
Patent•
11 Oct 1994TL;DR: In this paper, a solar array maximum power point tracking system for regulating the power output of a solar arrays associated with a spacecraft is presented, where an on-board computer measures the bus voltage and current from the solar array and generates a power calculation of the solar arrays power output.
Abstract: A solar array maximum power point tracking system for regulating the power output of a solar array associated with a spacecraft. An on-board computer measures the bus voltage and current from the solar array and generates a power calculation of the solar array power output. The on-board computer applies a first reference signal to a remote error amplifier representative of an incremental change in the solar array power. Additionally, the solar array bus voltage is applied to the remote error amplifier such that the remote error amplifier senses the solar array bus voltage and generates an output voltage indicative of the change of the solar array power. The output voltage of the error amplifier is applied to a power processor unit. The output voltage from the remote error amplifier and the bus voltage are applied to a power stage within the power processor unit. The power stage generates an output current that is applied to an arcjet thruster. The output current is also applied to a transconductive circuit that converts the output current to a voltage so as to condition the input voltage to the power stage.
144 citations
12 Apr 1994
TL;DR: A maximum power point tracker unit is developed for the optimum coupling of photovoltaic panels (PVP) to the batteries and load through a controlled DC-DC power converter (chopper) and regulates the panel output voltage at its optimum value in the control mode.
Abstract: A maximum power point tracker unit is developed for the optimum coupling of photovoltaic panels (PVP) to the batteries and load through a controlled DC-DC power converter (chopper). The system consists of three main units: (i) the photovoltaic panels that convert solar power to electricity; (ii) a chopper which couples the power of PVP to the load or batteries at a constant voltage; and (iii) maximum power point (MPP) computing unit that determines the set point of the chopper to keep the panel voltage at a maximum power transfer (MPT) condition. The tracking of the MPP for low power PVP (50 W-1 kW) is feasible only when the power consumption of the tracking unit is lower than the increase of the output power that they provide. The developed and tested circuit consumes only 40 mW, and therefore is suitable even for low power applications down to 50 W. The tracking unit performs MPP computation periodically through analog computing stages. The computation mode requires 20 mA from the /spl plusmn/5 V source for a 50 ms period. In the control and sleep mode, the consumption falls down to 4 mA. The developed unit regulates the panel output voltage at its optimum value in the control mode. The modes are switched by a timing circuit. The sleep mode is initiated when maximum PVP output power of the existent illumination level drops to a preset value, which cannot balance the losses of the chopper and the consumption of the MPP tracker unit. >
129 citations
Patent•
23 Sep 1994
TL;DR: In this paper, a controller monitors the solar array's output power and adjusts the battery charging by generating a current control signal that tracks a peak of the available output power, and sets a current limit such that the combined current draw of the plurality of dc-to-dc converters is substantially equal to the solar arrays's optimum current at which it provides its maximum available power.
Abstract: An electrical power conversion system that supplies the maximum available output power from a power source such as a solar array to a plurality of loads such as rechargeable batteries. The output power of the solar array peaks at an optimum current that is less than is maximum available output current. The system includes a controller and a plurality of dc-to-dc converters that charge the batteries. The controller monitors the solar array's output power and adjusts the battery charging by generating a current control signal that tracks a peak of the solar array's available output power and sets a current limit such that the combined current draw of the plurality of dc-to-dc converters is substantially equal to the solar array's optimum current at which it provides its maximum available power. The electrical power and control signals are transmitted from the power source and controller to the power converters on three bus bars, including a power bus, a control bus, and a common bus. The current control signal and the voltage control signal are multiplexed onto the single control bus. The controller and the dc-to-dc converters are mounted on planar printed circuit boards having clips arranged in a triangular pattern that allow the dc-to-dc converters to be easily attached to and removed from the buses.
117 citations
Patent•
28 Nov 1994
TL;DR: In this paper, an electric power supply system consisting of an air conditioner serving as load, a solar photovoltaic cell for supplying power to the air conditioning system, and a system power control circuit was described.
Abstract: This electric power supply system includes an air conditioner serving as load, a solar photovoltaic cell for supplying power to the air conditioner, and a system power control circuit and further including a commercial power source for use in combination with the solar photovoltaic cell for supplying additional power when insufficient, power is supplied from the solar photovoltaic cell to the air conditioner In an operation state of the air conditioner, the system power control circuit operates to regulate an operating point of the solar photovoltaic cell and variably regulate the supplied power from the solar photovoltaic cell while comparing required power of the air conditioner with the supplied power from the solar photovoltaic cell
109 citations
Patent•
10 Jun 1994TL;DR: In this paper, a power control method for fetching the maximum electric power from a battery power source and a system using such apparatus and method are provided, which comprises the steps of fluctuating an output voltage of the battery power sources and obtaining power values from at least (m) voltage signals from voltage detecting means and at least(m) current signals from current detecting means which were sampled at desired intervals, calculating a formula of function with a polar to approximate the relations between the voltage values and power values, obtaining a voltage at which a power is set to an extreme value from
Abstract: Power control apparatus and method for fetching the maximum electric power from a battery power source and a system using such apparatus and method are provided. For this purpose, the power control method comprises the steps of fluctuating an output voltage of the battery power source and obtaining (m) power values from at least (m) voltage signals from voltage detecting means and at least (m) current signals from current detecting means which were sampled at desired intervals, calculating a formula of function with a polar to approximate the relations between the (m) voltage values and (m) power values, obtaining a voltage at which a power is set to an extreme value from the formula of function with a polar, and setting the power at such a voltage into an output power set value and controlling the output power of the battery power source.
101 citations
05 Dec 1994
TL;DR: In this article, a maximum power point tracking control of photovoltaic array using fuzzy control is proposed, where the controller only uses the output power of the solar cell to get the maximum power.
Abstract: The solar cell has an optimum operating point to be able to get the maximum power. To obtain the maximum power from a photovoltaic array, the photovoltaic power system usually requires a maximum power point tracking controller. This paper proposes a maximum power point tracking control of photovoltaic array using fuzzy control; the controller only uses the output power. Therefore, this control method is easy to implement to a real system. Moreover, this method can track maximum power point rapidly with fuzzy inference even if the optimum operating point changes. The usefulness of this control method is confirmed by experiments using step-down chopper with constant resistive rod. >
85 citations
Patent•
23 Dec 1994TL;DR: An interconnectable power supply module includes a battery, a battery charger for charging the battery, and a power generator capable of converting an electrical charge stored in the battery to generate output power for an external load as discussed by the authors.
Abstract: An interconnectable power supply module includes a battery; a battery charger for charging the battery; a power generator capable of converting an electrical charge stored in the battery to generate output power for an external load; a control unit for controlling operation of the power supply module; a power supply plug for receiving external power from an external power source; a power supply socket capable of coupling the external power received from the external power source to an adjacent power supply module; an external load output socket, selectively coupled to one of the external power source and the power generator, for providing output power to the external load; and a connecting terminal capable of coupling the external load output power to the adjacent power supply module.
73 citations
20 Jun 1994
TL;DR: A novel multi-step PWM inverter for a solar power generation system that has many features such as good output waveform, small size of filter, low switching losses, and low acoustic noise is presented.
Abstract: In this paper, the authors propose a novel multi-step PWM inverter for a solar power generation system. The circuit configuration is constructed by adding a bi-directional switch to the conventional bridge type inverter circuit using the isolated DC power supply for which the solar cell is very suitable. The new type of PWM inverter presented has many features such as good output waveform, small size of filter, low switching losses, and low acoustic noise. In this paper the authors describe the circuit configuration, control method and the characteristics of the system, and they also investigate the relation between the inverter and the solar cell characteristics. Finally, some simulation results and experimental results are shown. >
67 citations
Patent•
27 Dec 1994
TL;DR: In this article, the authors proposed a linkage type solar light power generating device with the abnormality checking function for the solar battery module which detects solar battery output voltages by strings and can automatically check a solar battery outputs and perform safe and secure maintenance management.
Abstract: PURPOSE: To provide a linkage type solar light power generating device with the abnormality checking function for the solar battery module which detects solar battery output voltages by strings and can automatically check a solar battery output and perform safe and secure maintenance management. CONSTITUTION: The linkage type solar light power generating device 1 consists of a solar battery array 2 and a linkage inverter 3, and the DC power generated by the solar battery array 2 is converted by the linkage inverter 3 into AC power of the same quality as a system power source 4 to perform linkage operation. The AC power is supplied to a load 5 and its excessive power returns to the system power source 4 as a tidal current. The solar battery array 2 is constituted by connecting plural series-connected solar battery modules in parallel and serial components of the solar battery modules are regarded as strings S 1 -Sn n . The output voltage Vs s1 and Vs n of the respective strings S 1 -S n are compared with an input voltage V in to detect and specify abnormality of strings. COPYRIGHT: (C)1996,JPO
50 citations
Patent•
04 Aug 1994TL;DR: In this article, a peak power tracker is used for controlling the negative impedance of converter for transferring maximum power from a solar array source to a battery and load typically used in space vehicles.
Abstract: A peak power tracker apparatus is used for controlling the negative impedance of converter for transferring maximum power from a solar array source to a battery and load typically used in space vehicles, by capacitive differentiation sensing the solar array source voltage for sensing the peak power point at which the source voltage first begins to become unstable and collapses, and then providing a step down control signal which controls a current mode pulse width modulator to control the converter to vary the negative impedance into the solar array then reserving back to a stable point at which the tracker then provide a linear ramp signal to the modulator to control the converter to drive the source voltage again to the peak power point, so as to alternate the feedback loop and source voltage between a stable point and the peak power point so as to transfer maximum power while preventing the source voltage to pass through an unstable point for discontinuous but stable operation at peak power transfer which is independent of array performance and is adaptable to a wide range of power sources.
02 Oct 1994
TL;DR: In this paper, an adaptive control strategy for the brushless doubly-fed machine (BDFM) applied to variable speed wind power generation systems is presented. But the authors do not consider the measurement of mechanical quantities.
Abstract: The paper presents an adaptive control strategy for the brushless doubly-fed machine (BDFM) applied to variable speed wind power generation systems. A 7 kW proof-of-concept laboratory prototype is used to investigate the proposed control algorithm. The paper discusses the use of an adaptive maximum power point tracking (MPPT) strategy to implement an efficiency maximization loop in parallel with the regular maximum tip-speed-ratio tracker, without the measurement of mechanical quantities. The overall power output of the generation system is increased with a minimal increase in controller cost. A 100 kW case study is included to describe the prospects of the proposed control strategy for a typical wind power/generation site on the Oregon coast. >
05 Sep 1994
TL;DR: In this paper, a general applicable model has been developed for the coupling of two single-phase systems by a voltage link with small storage capacitance, which allows the decoupling of the pulsating mains power from the panel.
Abstract: Important drawbacks of solar power generation are the DC-wiring and fusing needed for the serial and parallel connection of solar panels. These problems can be reduced to AC wiring and fusing by using a modular set up of panels together with integrated single phase DC-AC power converters on a power level of approximately 200 W. A general applicable model has been developed for the coupling of two single-phase systems by a voltage link with small storage capacitance. It allows the decoupling of the pulsating mains power from the panel. Based on this model, which avoids the need of large filters, a sophisticated control principle has been developed. The result is a power converter which allows the operation in the maximum power point without any power pulsation In the solar panel. The required reactive elements, and therefore the size of the power converter, are very small. >
TL;DR: In this paper, the authors present results obtained for sizing the photovoltaic array and the battery in PV systems with short-term energy storage, based on maximizing the utilization of the array output energy, and minimizing losses associated with charging and discharging the battery.
30 Oct 1994
TL;DR: In this article, a utility-connected photovoltaic inverter called LINE BACK, which is suited to small-scale PV generation systems for use in private households, has been developed.
Abstract: A new utility-connected photovoltaic inverter called "LINE BACK", which is suited to small-scale photovoltaic generation systems for use in private households, has been developed. The inverter converts DC power generated by rooftop photovoltaic cells into AC power, and provides it to house loads connected to the utility line. When photovoltaic power is greater than the loads, the excess power is fed to the utility line through a reverse power flow. The inverter has several special functions such as a utility protection relay, maximum power point tracking (MPPT) control, automatic operation with photovoltaic power, detection of islanding operation, and utility voltage compensation for reverse power flow. These functions and characteristics conform to the "Utility-Connected System Technical Guidelines" revised by Japan's Ministry of International Trade and Industry in March 1993. >
05 Dec 1994
TL;DR: In this article, the ideas behind this portable and expandable AC PV power system are highlighted, and the measurements show a power factor exceeding 0.99 at full load, whilst at 12 W partial load the power factor is better than 0.89.
Abstract: An AC module is a PV module with an integrated DC/AC power converter which generates grid conforming AC power. In this paper, the ideas behind this portable and expandable AC PV power system are highlighted. The block diagram, the principle of operation and test results of a 130 W inverter are shown. The measurements show a power factor exceeding 0.99 at full load, whilst at 12 W partial load the power factor is better than 0.89. The harmonic distortion decreases from 8% at 30 W to 5% at 50 W and slightly decreases further at higher power levels. Previous measurements showed that an efficiency over 90% over a wide operation range is obtained. It is estimated that the cost price of the "touch safe" inverter (dimensions 100*100*20 mm), when produced in large quantities is between 0.5 and 1 $/Wp. The price performance ratio is obtained by application of resonant switching techniques enabling low component size and costs.
Patent•
25 Nov 1994
TL;DR: In this paper, the output voltage of an inverter is adjusted as to be a voltage which is within the allowable voltage range of a load machine and with which the power consumption is minimized.
Abstract: PURPOSE: To reduce a power consumption and extend the service life of an appliance by a method wherein the output voltage of an inverter is so adjusted as to be a voltage which is within the allowable voltage range of a load machine and with which the power consumption is minimized. CONSTITUTION: An AC power from a commercial AC power supply 1 is converted into a DC power by a rectifier 10 and used for charging a battery 20 and, at the same time, inputted to an inverter 30 which outputs an AC output 2 of a rated voltage as an initial voltage through a switch 41. Then, by changing a reference value 31 within the allowable input voltage range of a load machine, the inverter voltage is gradually changed and the respective products of the detected values of an output voltage detector 34 and the detected values of an output current detector 35 are obtained by a multiplier 33 along the lapse of time to measure the power consumption of the load machine. A CPU 32 stores an inverter voltage when the power value is minimum and fixes the reference value of the output voltage to that value and controls so as to have a power with that voltage supplied to the load thereafter. As a result, the power consumption can be reduced and the service life of an appliance can be extended. COPYRIGHT: (C)1996,JPO
Patent•
22 Feb 1994
TL;DR: In this article, a hill climbing method is used to hold the operation point of a solar battery to a place around a really optimum operation point at that time by calculating the average value of output voltage at every prescribed period and periodically substituting virtual optimum operation voltage for the average values at the time of increasing/decreasing the change width of a control target value in accordance with a difference between the output voltage measured value and virtual optimum operator voltage.
Abstract: PURPOSE: To hold the operation point of a solar battery to a place around a really optimum operation point at that time by calculating the average value of output voltage at every prescribed period and periodically substituting virtual optimum operation voltage for the average value at the time of increasing/decreasing the change width of a control target value in accordance with a difference between the output voltage measured value and virtual optimum operation voltage. CONSTITUTION: Maximum power point tracking (MPPT) control by a hill climbing method, which a microcomputer 24 executes, is constituted by a reference setting processing for periodically updating virtual optimum operation voltage VSop and a control target setting processing for setting a current amplitude command lamp based on virtual optimum operation voltage SVop, and it is executed at every 50ms, for example. In the routine of the reference setting processing, the output voltage Vi of the solar battery 10 is measured at the period of 500ms, for example, and virtual optimum operation voltage SVop is updated whenever about thirty pieces of measured values are obtained. Thus, virtual optimum operation voltage becomes a value approximated to real optimum operation voltage, and the change width of the control target can be optimized. COPYRIGHT: (C)1995,JPO
Patent•
28 Jun 1994
TL;DR: In this article, a simplified photovoltaic power-generation system is presented, which is composed of a solar-cell module 5 which is laid on a roof part 3 for a carport 1 and in which many solar cells are arranged side by side so as to be connected to each other.
Abstract: PURPOSE:To effectively utilize a photovoltaic power-generation system by a method wherein the photovoltaic power-generation system is popularized and promoted widely to a general household so as to be installed simply and at low costs. CONSTITUTION:A household simplified photovoltaic power-generation system is composed of a solar-cell module 5 which is laid on a roof part 3 for a carport 1 and in which many solar cells are arranged side by side so as to be connected to each other, of a household power conditioner 8 which is connected to the solar-cell module 5 and which converts DC generated electric power into AC electric power so as to be supplied to a load inside a household and of a battery charger 9 which converts the AC electric power from the power conditioner 8 again into the DC electric power so as to be stored in a battery 15 for gasoline car of an electric car 15 or which converts the stored electric power into AC electric power so as to be supplied to the load inside the household. The photovoltaic power generation system can be linked to a distribution system by a connecting plug 12 at the tip of a vord 11 extended from the power conditioner 8 and the battery charger 9.
TL;DR: In this paper, a buck-boost PWM power inverter and its application for residential photovoltaic system is presented, and the ripple component of the array current and the power flow between the interface and the utility line are derived.
Abstract: This paper presents a buck-boost PWM power inverter and its application for residential photovoltaic system. The PWM power inverter is realized by driving a inverter constructed with a high frequency buck-boost chopper in the discontinuous conduction mode (DCM). Photovoltaic system with the power inverter has the following advantages: (1) The power generated by the photovoltaic array can be transfered to the load and the utility line under any array voltage, (2) Isolation between the photovoltaic array and the utility line is performed by a small high frequency reactor operating as energy storage element, (3) There is no need of a reactor to link the utility line, (4) Unity power factor operation is provided, (5) So the system configuration is very simple. The input-output characteristics of the system is analyzed. As the result, the ripple component of the array current and the power flow between the interface and the utility line are derived, and verified experimentally.
05 Sep 1994
TL;DR: In this paper, a DC-to-RF power inverter consisting of four branches, each branch consisting of three MOSFETs connected in parallel to enhance the power handling capability, was built for driving a high frequency, high power ultrasonic transducer with an output power of 600 W operating at 1 MHz.
Abstract: A full-bridge MOSFET DC-to-RF power inverter consisting of four branches, each branch consisting of three MOSFETs connected in parallel to enhance the power handling capability, was built for driving a high frequency, high power ultrasonic transducer with an output power of 600 W operating at 1 MHz. When the power inverter was connected to the ultrasonic transducer through an output transformer with a primary-to-secondary winding ratio of 2 to 1, the load impedance looking into the load from the inverter was 3.5 ohms at 1 MHz, and was high enough to drive the load with high power conversion efficiency, i.e., over 80%. >
05 Dec 1994
TL;DR: From the results it can be concluded that inverters can at least be undersized to 65% of the PV peak power without any significant loss of energy production.
Abstract: Preliminary results on the design and performance of three multi-array grid connected PV systems on flat roofs are presented. From the results it can be concluded that inverters can at least be undersized to 65% of the PV peak power without any significant loss of energy production. These results confirm the findings from model calculations carried out as a part of the design process.
24 Aug 1994
TL;DR: The paper presents laboratory implementation of a photovoltaic artificial neural network (ANN) based maximum power tracking controller that is compared with a well tuned conventional proportional plus integral controller to validate its effectiveness.
Abstract: The paper presents laboratory implementation of a photovoltaic artificial neural network (ANN) based maximum power tracking controller. The control objective is to track the maximum available solar power in a photovoltaic array interfaced to an electric utility grid via a line-commutated inverter. The inverse dynamic characteristics of this interface scheme is identified via off-line training using a multi-layer perceptron type neural network. The ANN output is used as the control signal to vary the line-commutated inverter firing control angle, hence track the available maximum solar power. The weights of the ANN are also updated by a novel on-line training algorithm which utilizes the on-line power mismatch error. This ensures on-line maximum solar power tracking. The proposed controller is compared with a well tuned conventional proportional plus integral controller to validate its effectiveness. >
TL;DR: In this article, a single-phase PWM current source inverter for the utility interactive photovoltaic generation system is proposed, in which a double frequency parallel resonance circut (LC tank circuit) is inserted in the dc side of the inverter.
Abstract: A suitable single-phase inverter for the utility interactive photovoltaic generation system is proposed. The single-phase PWM current source inverter has a novel circuit configuration which is added a auxiliary branch to the normal single-phase bridge circuit. In order to reduce the size and weight of the dc reactor, a double frequency parallel resonance circut (LC tank circuit) is inserted in the dc side of the inverter. In result, the double frequency voltage appeared in the dc side of the inverter due to the pulsation of the single-phase instantaneous power is perfectly suppressed by the tank circuit. The constant dc current without pulsation is supplied from PV array to the inverter. The inverter provide a sinusoidal ac current for domestic loads and the utility line with unity power factor.The virtual maximum power of the PV array can be obtained without any feedback control. In the system, the PV array can play an important role as a current-limitter by its V-I characteristics. Computed waveformes by simulation are shown. The excellent inverter equipment will be realized with smaller size and lighter weight than a conventional inverter.
Patent•
29 Jul 1994
TL;DR: In this paper, a microcomputer 24 calculates the output power Po of a solar battery based upon A/D converted voltage Vi and current Ii, executes arithmetic processing for MPPT control for maximizing the output Po and outputs a current amplitude command value lamp.
Abstract: PURPOSE:To reduce an output power loss in the vicinity of a maximum power point of a solar battery and to improve the application efficiency of the battery by comparing old output power with output power measured lately and controlling operation voltage in accordance with the compared result. CONSTITUTION:A microcomputer 24 calculates the output power Po of a solar battery based upon A/D converted voltage Vi and current Ii, executes arithmetic processing for MPPT control for maximizing the output power Po and outputs a current amplitude command value lamp. At the time of executing the arithmetic processing for MPPT control, the output power Po (new power Poc) calculated lately is compared with reference output power Po (old power Pof) calculated preceding time, a voltage command value Vref to be a target value for the operation voltage Vop (= input voltage Vi) is set up to various values in accordance with the compared result and a current amplitude command value lamp for equalizing the operation voltage Vop to the voltage command value Vref is found out by operation and outputted to a digital signal processor.
TL;DR: PVFORM as a whole was not found to have any major flaws, but was found to overpredict actual power output due mostly to assuming ideal array sun-tracking performance and ideal maximum power point tracking.
Patent•
30 May 1994
TL;DR: In this paper, a pyrheliometer and a thermometer are placed nearby a solar battery to detect the largest electric power that the battery can generate, and a microcomputer compares the maximum electric power of the solar battery with the rated output of the inverter main circuit and commands the control circuit to operate below or at the maximum electricity point when the maximum power is larger than the rated power point.
Abstract: PURPOSE: To protect an inverter main circuit which converts the DC electric power obtained from a solar battery into AC electric power and outputs it by controlling the output of the inverter, equipped with the inverter main circuit and a control circuit which controls the operation of the inverter main circuit, according to the power generating capability of the solar battery CONSTITUTION: A pyrheliometer and thermometer 6 which detects the largest electric power that the solar battery 1 can generate are arranged nearby the solar battery 1 A microcomputer 5 compares the maximum electric power of the solar battery 1, detected from the measurement data from the pyrheliometer thermometer 6, with the rated output of the inverter main circuit 2 and commands the control circuit 3 to operate below the rated output when the maximum electric power is larger than the rated output or to operate at the maximum electric power point when the maximum electric power is smaller than the rated output COPYRIGHT: (C)1995,JPO
TL;DR: The usefulness and validity of proposed control method are proved experimentally under constant natural solar insolation and can track maximum power point rapidly with fuzzy inference even if the optimum operating point changes.
Abstract: The solar cell has an optimum operating point to be able to get maximum power. To obtain maximum power from photovoltaic array, photovoltaic power system usually requires maximum power point tracking control ler. The output characteristics of solar cell are nonlinear, and these characteristics vary with load, solar insolation, cell temperature. Therefore, the tracking control of maximum power point is the complicated problem. This paper proposes the maximum power point tracking control of photovoltaic array using fuzzy control. To obtain maximum power from photovoltaic array, the fuzzy controller only uses the output power. Therefore this control method is easy to implement to real system. Moreover, this method can track maximum power point rapidly with fuzzy inference even if the optimum operating point changes. The usefulness and validity of proposed control method are proved experimentally under constant natural solar insolation.
05 Dec 1994
TL;DR: In conventional solar air conditioning systems, the diode rectifier is used to build up DC link voltage from an AC utility source, but the reversal of power flow cannot be made, so some advantages can be obtained by adopting PWM power converters in solar air conditioners.
Abstract: In conventional solar air conditioning systems, the diode rectifier is used to build up DC link voltage from an AC utility source. The diode rectifier is simple and cheap but the reversal of power flow cannot be made. It can derate the utilization of solar cells and there problems of low power factor and harmonics at the AC input side have also occurred. Hence, in addition to peak power cutting in summer, some advantages can be obtained by adopting PWM power converters in solar air conditioners. As a result, the characteristics of the PWM power converter, such as low distorted current waveform and unity power factor are obtained. The proposed system is also verified by examining the dynamics of the PV power system to step load change as well as power reversal testing.
Patent•
20 Oct 1994
TL;DR: In this article, a peak power curve 10 is prepared by connecting the maximum output points of the power generating characteristic curve of the solar battery with sunshine and temperature as parameters, and a maximum output point of the battery is retrieved by changing the DC voltage set value of the inverter along the peak-power curve 10.
Abstract: PURPOSE: To stably perform the following control of an inverter by reducing the delay of peak point detection concerning the maximum output following control method for photovoltaic power generation system for controlling the inverter so as to maximize the output power of a solar battery. CONSTITUTION: A peak power curve 10 is prepared by connecting the maximum output points of the power generating characteristic curve of the solar battery with sunshine and temperature as parameters, and the maximum output point of the solar battery is retrieved by changing the DC voltage set value of the inverter along the peak power curve 10. Since the change width of a DC voltage at a peak point is narrow, even when the DC voltage of the inverter is changed near this curve 10, a control system is not made instable. Further, since the retrieval width of the peak point is narrow, the delay of peak point detection is reduced. COPYRIGHT: (C)1996,JPO