114 results about "Mppt algorithm" patented technology

A photovoltaic energy conversion system includes a distributed control structure for groups of cells of each multi-cellular panel, the components of which are entirely physically integrated in the photovoltaic panel. Each multi-cellular photovoltaic panel has a DC bus, supplied in parallel by a plurality of DC-DC converters, each provided with a controller that controls the working point of the photovoltaic cells coupled to the input of the DC-DC converter for a maximum yield of electric power by implementing a relatively simple MPPT algorithm. The controller includes a logic circuit and A/D converters of analog signals representing the input voltage and the input current generated by the group of cells that is coupled to the input of the DC-DC converter and optionally also of the output voltage of the converter, and a relatively simple D/A converter of the drive control signal of the power switch of the DC-DC converter.

The invention discloses a VSG(Virtual Synchronous Generator)-based control structure for active supporting of the grid frequency and voltage of a PMSG (Direct Drive Permanent Magnet Synchronous Generator). The control structure is composed of a wind turbine generator and a back-to-back four-quadrant converter. The back-to-back four-quadrant converter consists of a machine-side converter and a grid-side converter; the machine-side converter is used for maintaining the voltage of a direct-current side capacitor; and the grid-side converter is used for controlling normal operation of the rotatingspeed of a draught fan and power balancing based on an MPPT algorithm and carrying out active supporting on the grid frequency and voltage based on a control strategy of the VSG, wherein dynamic support is realized by releasing the energy of the direct-current side capacitor and the kinetic energy of the rotor during supporting. According to the control structure, a defect that grid connection can not be realized until the PPL phase locking is used by the wind turbine generator is overcome. The wind turbine generator is equivalent to a voltage source type VSG to support fluctuation of the grid voltage and frequency.

The invention discloses a global MPPT (Maximum Power Point Tracking) method and device under uneven illumination. When a photovoltaic array is judged to have different illumination condition regions, i.e., when the photovoltaic array is judged to be locally shielded by shadows, different from the prior art in which an entire feature curve is scanned in a global scanning mode to acquire a global maximum power point, according to the global MPPT method and device, a short-circuit current near maximum power points in each illumination condition region is scanned in a jumping mode, a maximum value in the maximum power points in each illumination condition region is searched, and then after a global maximum power point is found, a general MPPT algorithm is executed. According to the global MPPT method and device disclosed by the invention, when an effect of improving power generation efficiency of a photovoltaic system is achieved, operation and maintenance staffs can be helped to rapidly position a shadow fault, so that operation and maintenance efficiency and entire power generation benefits of a power station are further promoted.

The invention provides an improved particle swarm MPPT algorithm based on dynamic inertia weights and multi-threshold restart conditions and relates to the technical field of photovoltaic power generation. The algorithm dynamically resolves inertia weight values with the distance between particles and the optimal solution and the number of times of iteration as variables, and, compared with the methods with fixed inertia weights or segmented values of weights, the algorithm has the advantages of high convergence speed and small oscillation amplitude and achieves the objective of dynamically adjusting an iteration process according to search conditions. Multi-threshold restart conditions are set for complicated and ever-changing external environment, so that the algorithm, compared with theconventional fixed-cycle scanning method, prevents unnecessary voltage full-range scanning and solves the problems of frequent oscillation of systems, increase of power loss and tracking lag resulting from fixed cycles of the fixed-cycle scanning method; compared with the method with a single condition of using power change for judgment, the algorithm enables the change of the external environment to be identified more accurately and solves the problem that a system cannot be restarted normally because of monitoring failure caused by the single judgment condition.

The invention discloses a photovoltaic module MPPT algorithm based on a global scanning and quasi-gradient disturbance observation method. The photovoltaic module MPPT algorithm comprises the following steps: positioning the global maximum power point of a photovoltaic module by using a programmable DC (direct current) electronic load; realizing maximum power output of the photovoltaic module through the quasi-gradient disturbance observation method; and finally, switching the scanning control policy by using constant power difference in the case of environmental sudden change. According to the embodiment of the photovoltaic module MPPT algorithm of the invention, the simulation result indicates that the method has relatively good dynamic performance and steady-state performance in any working condition.

The invention discloses a photovoltaic power generation system environment self-adaptive type MPPT (maximum power point tracking) method. A voltage correcting parameter delta U and PI are introduced to control a link, a duty ratio D of a direct-current chopper is regulated in real time, maximum power point voltage Um optimal-searching speed is increased, the power loss is reduced, and the maximum power point voltage Um is changed in real time along with the environmental conditions, the incremental conductance method (I&S) optimal-searching step length is reduced, and the photovoltaic battery MPPT is quickly and accurately realized, the defects that a conventional MPPT algorithm is easy to affect by the environment, the robustness is poor and the power loss is relatively large are improved, and the defects that the intelligent type MPPT algorithm is complex and easy to be locally optimal are also avoided.

The invention relates to a photovoltaic module MPPT algorithm based on a ripple association method. The algorithm is technically characterized mainly in that a photovoltaic battery model and a Boost circuit model are created; a ripple signal with the frequency equal to a switch frequency is obtained through a second-order improper integral-orthogonal signal generator; a reference voltage value isupdated, an error signal between the reference voltage value and an actual voltage value is adopted as input of a PI controller, the output of the PI controller is adopted as a duty ratio modulating signal, and a control signal obtained by means of a PWM circuit acts on a switch tube of a Boost circuit; an AND triggering threshold value of a transient state detector is created, when the radiationintensity of the sun changes suddenly, the transient state detector works, and the output of a sampling retainer is adopted as a reference voltage value of the next moment. The algorithm is reasonablein design, easy to implement and capable of enabling a photovoltaic grid-connected system to quickly track a maximum power point under different illumination, temperature and load conditions, enabling the system to stably work around the maximum power point and improving the conversion efficiency of photovoltaic batteries.

The invention discloses a method for realizing a simulation circuit based on a double linear approximate value MPPT (Maximum Power Point Tracking) algorithm. The method is centrally characterized in that the double linear approximate value algorithm is applied; a double linear approximate computation circuit consists of a photosensitive diode and a thermistor, the reference voltage of a maximum power point is computed and outputted according to real-time illumination and temperature, a steady error signal with reference voltage and photovoltaic array real-time voltage is outputted by an adder and a PI (proportional integral) controller, and a duty ratio of a Buck step-down circuit is changed by a PWM (pulse width modulation) voltage comparator, so as to realize the MPPT; and the method comprises five specific steps. The method has the advantage that compared with the conventional MPPT control technique, the principle and the control algorithm are easier, the cost is lower, the vibration on the maximum power point is little, the control precision is high, the response speed is high, and the simulation circuit can be easily embedded into photovoltaic systems with different scales.

The invention discloses an MPPT (maximum power point tracking) control device and an MPPT control method of a photovoltaic inverter. The MPPT control method includes the steps: A, sampling direct-current voltage Ux and direct current Ix of a direct-current side of the photovoltaic inverter, and computing input power Px of the direct-current side of the photovoltaic inverter; B, judging whether the direct-current voltage Ux is not larger than a voltage minimal value U1 or not, if so, updating the voltage minimal value U1 and corresponding input power P1 and switching to D, and otherwise switching to C; C, judging whether the direct-current voltage Ux is not smaller than a voltage maximum value U2 or not, if so, updating he voltage maximum value U2 and corresponding input power P2 and switching to the D, and otherwise switching to E; D, computing a voltage result value U; and E, sending PWM (pulse-width modulation) signals of switches in the photovoltaic inverter according to the voltage result value U. The MPPT control method is simple in sampling MPPT algorithm, easy to implement, rapid in processing, stable in control and capable of improving use efficiency of solar cells.

A device for optimizing the electric power produced by direct current electric power generators, specifically photovoltaic panels, can be interposed between the generators of a string and its inverter and it includes a DC/DC conversion module suitable to implement an algorithm of MPPT, bypass means and a reactive energy compensation module. By measuring the voltage and current at input and output of the device a suitable algorithm activates and manages the above modules to extract from the panels the maximum amount of energy.

The present invention discloses a photovoltaic cell MPPT simulation method based on fuzzy logic control. The method comprises design of a fuzzy logic controller and fuzzy logic control simulation; wherein the design of the fuzzy logic controller comprises: determining input/output amount and the structure of the controller, determining the fuzzy subset and the domain of the input/output amount, determining the subordinating degree function of the input/output amount and determining the fuzzy control rule, etc. Through combination of the control idea of the perturbation and observation method and the fuzzy logic control theory, the photovoltaic cell MPPT simulation method based on fuzzy logic control is provided; the simulation model is built to compared with and simulate the perturbation and observation method and the conductance increment method; according to the simulation result, the fuzzy logic control is very suitable for the MPPT control of the photovoltaic system so as to rapidly and accurately lock the MPP range, and the fluctuation is little after the system is stable.

The present invention discloses an improved MPPT algorithm with reduced influence of partial shading on a photovoltaic system. First step: a true maximum power point domain is determined, and the operating voltage of the system is shifted thereto with guaranteed celerity of tracking; given that the intersection point of the equivalent resistance line Rpm = Vpm/Ipm and the V-I characteristic curve for photovoltaic arrays under uniform light is the maximum power point, and the operating voltage at the end of the first step is determined by using the intersection point of this line and the V-I characteristic curve for photovoltaic arrays under partial shading; to prevent false tracking caused by the local minimum point and the pseudo maximum power point to the algorithm, the extreme points tracked during scanning are required to be recorded in the first step; and second step: maximum power point tracking is carried out from the operating voltage determined in the first step by using the incremental conductance algorithm. The improved MPPT algorithm with reduced influence of partial shading on a photovoltaic system may be less affected by the environment with high accuracy, less false tracking and good operating effect.

The present invention relates to a photovoltaic array state determination method. The method comprises: collecting feature parameters that affect each photovoltaic array state; introducing a time sequence node and a photovoltaic array monitoring point, and establishing a parametric value model from latitudinal and longitudinal dimensions; constructing a photovoltaic array running state assessment model based on a positive and negative ideal point assessment scheme; and establishing a time function relationship between a state assessment result set and each longitudinal and latitudinal parametric value by using a Gaussian curve fitting method, and in combination with an array I-V curve and an irradiance-temperature curve, accurately assessing a current photovoltaic array state from longitudinal and latitudinal angles, analyzing an abnormality cause, and proposing an operation and maintenance measure. By performing state assessment according to a plurality aspects of feature parameters, accuracy of state assessment can be improved, real-time operation and maintenance of a photovoltaic array is facilitated, and the method lays a good foundation for improving power generation efficiency of a photovoltaic array group and searching for a better MPPT algorithm and has high application value.

The invention discloses a novel MPPT algorithm and a method for obtaining hardware for the novel MPPT algorithm. The novel MPPT algorithm comprises the steps that the open-circuit voltage of a solar cell panel and the battery voltage at present are sampled and measured; when the open-circuit voltage of the solar cell panel is higher than the battery voltage, tracking is started, and a master control unit outputs PSMC1A, PSMC1B and PSMC2A; the PSMC1A outputs PWM1 through an AND logic circuit, and the PSMC1B and PSMC2A output PWM2 through the AND logic circuit; the PWM1 and the PWM2 output PWMH and PWML respectively through a driving circuit unit; a synchronous rectification unit is driven by the PWMH and the PWML to scan the P-V curve of the solar cell panel, and the maximum power point of the solar cell panel is obtained by sampling output current in real time through a comparison current sampling unit. According to the novel MPPT algorithm and the method for obtaining the hardware for the novel MPPT algorithm, the maximum power point of the solar cell panel can be found accurately and rapidly, limitation of the environmental factors such as illumination, temperature and shadow shading is avoided, the tracking speed is high, and the efficiency is high.

A photovoltaic power generation system MPPT algorithm based on a voltage pre-estimating method is a maximum power point tracking algorithm applied to a photovoltaic array under complicate illumination conditions. The photovoltaic array is in a DMPPT circuit structure and a simplified equivalent output feature curve of individual photovoltaic cell mode in the photovoltaic array can be achieved; and a computational formula of work voltage pre-estimating value of the photovoltaic array formed by a serial connection of two photovoltaic cell sets under different light strength is achieved. In the photovoltaic power generation system MPPT algorithm based on the voltage pre-estimating method, the photovoltaic system is designed to be in a DMPPT circuit structure; a photovoltaic generation system output feature of the structure is employed to reckon the optimal voltage range of the work points of the photovoltaic array according to the feature curve principle; the optimized voltage pre-estimating value enables the system to effectively skip a secondary merit; after the optimal voltage range is determined, a P&O method is combined; and maximum power point tracking algorithm under complicate illumination conditions can be realized.

The invention discloses a micro photovoltaic grid-connected inverter and a grid-connected control method of the micro photovoltaic grid-connected inverter. The inverter comprises an active-clamp interleaved flyback circuit, a full-bridge circuit, an EMI circuit, a detection circuit and a main control chip, wherein direct-current voltage output by an external solar panel is input to the interleaved flyback circuit, the interleaved flyback circuit comprises two flyback circuits and two active-clamp circuits, the two flyback circuits alternately work with a phase difference of 180 degrees, and the output end of the interleaved flyback circuit is connected with the input end of the full-bridge circuit; the full-bridge circuit comprises a gate drive transformer, an upper bridge arm and a lower bridge arm, the upper bridge arm and the lower bridge arm are driven by the gate drive transformer, and the full-bridge circuit is connected with a power network through the EMI circuit; the main control chip is in data communication with the interleaved flyback circuit and the full-bridge circuit through the detection circuit. The method comprises a deadbeat grid-connected algorithm based on current control, an MPPT algorithm based on current disturbance, and the like. The micro photovoltaic grid-connected inverter disclosed by the invention has the advantages of low grid-connected harmonic rate, high efficiency of maximum power tracking and strong anti-shadow ability.

The invention discloses a multi-peak-value MPPT algorithm. According to the algorithm, during starting, a large-step-length global scanning algorithm is utilized to quickly locate all peak value intervals, afterwards, a filtering algorithm is utilized to reduce the peak value intervals, dichotomy is utilized to find local peak values of all the filtered 1-5 peak value intervals, and finally the maximum value of the local peak values are regarded as the global maximum power point; through an acknowledgment mechanism, a solved GMPP is confirmed, the algorithm is prevented from being misjudged, and finally a three-point method algorithm is utilized to make the system dynamically track the GMPP under a changing environment. By means of the multi-peak-value MPPT algorithm, the photovoltaic system maximum power point tracing speed is increased, so that the system quickly adapts to the environment change, the algorithm is prevented from being involved into the local optimal point, the misjudgment rate of the algorithm is reduced, the algorithm complexity and implementation cost are lowered, and the system performance is improved.

The embodiment of the invention provides a control method and device for an anti-snaking shock absorber, and the method comprises the steps: obtaining a transverse acceleration signal of a framework,and carrying out the first preprocessing of the transverse acceleration signal; obtaining the pressure difference between two cavities of a anti-snaking shock absorber piston, and carrying out secondpretreatment on the pressure difference; according to the first preprocessing result and the second preprocessing result, obtaining an MPPT algorithm objective function value at the current moment andan MPPT algorithm objective function value at the previous moment, and comparing the MPPT algorithm objective function value at the current moment with the MPPT algorithm objective function value atthe previous moment; and according to the comparison result, controlling the adjusting direction of an electromagnetic proportional valve of the anti-snaking shock absorber. According to the method, the damping force of the anti-snaking shock absorber can be adjusted in real time, and the adaptability of the shock absorber in different wheel abrasion states and the dynamic stability of a motor train unit are improved.

The invention discloses an adaptive incremental conductance MPPT algorithm which is based on the incremental conductance algorithm and uses multiple step models combined with allowable errors to accurately control the converting circuit duty ratio D and to increase tracking efficiency and accurately respond to rapidly changing lighting conditions. The adaptive incremental conductance MPPT of the invention is characterized by quick tracking and accurate response under sudden changes in illumination with little fluctuation and without stable oscillation. Compared with the existing MPPT, the invention has better tracking performance, accurate response, no oscillation, high tracking efficiency, easy implementation, and reduced energy loss. The invention solves the problems that the existing algorithms often have oscillation, inaccurate response, low tracking efficiency and high difficulty in implementation. The improved step size model and precise directional control in the algorithm of the present invention are effective.

A solar cell array maximum power tracking hardware circuit comprises a differential module, a voltage division module, a switch energy storage module, a voltage comparison module, a setting and resetting module, a logic selection module and a filter module. The differential module is electrically connected with solar array output voltage VSA and solar array output current ISA, the voltage division module is electrically connected with the differential module, the switch energy storage module is electrically connected with the voltage division module, the voltage comparison module is electrically connected with the switch energy storage module, and the filter module is electrically connected with the setting and resetting module and the logic selection module. On the basis of inherent characteristics of a solar array output characteristic curve, voltage and current are disturbed alternately, maximum power tracking can be realized simply, quickly and efficiently; an algorithm has no direct relation with power, multiply-divide operation is not needed, and the hardware circuit is easy to realized; disturbance is continuous, and the hardware circuit has better reliability, so that anti-radiation characteristics of MPPT algorithm control signals are improved; the hardware circuit has autonomy and high accuracy, can quickly and accurately track maximum power point and adapts to space application needs.