A system and method for combining power from DC power sources. Each power source is coupled to a converter. Each converter converts input power to output power by monitoring and maintaining the input power at a maximum power point. Substantially all input power is converted to the output power, and the controlling is performed by allowing output voltage of the converter to vary. The converters are coupled in series. An inverter is connected in parallel with the series connection of the converters and inverts a DC input to the inverter from the converters into an AC output. The inverter maintains the voltage at the inverter input at a desirable voltage by varying the amount of the series current drawn from the converters. The series current and the output power of the converters, determine the output voltage at each converter.

Distributed Power Harvesting Systems Using DC Power Sources

A monitoring system and method for monitoring performance of individual powers sources in a distributed power source system A monitoring module is coupled to each of the power sources, or to each string of serially connected power sources, to monitor and collect data regarding current, voltage, temperature and other environmental factors at the power source The collected data is transmitted over a power line to a central analysis station for analysis Data collected from each source indicates malfunction or degradation at the source Comparison of data collected from adjacent sources filters for environmental factors impacting neighboring sources such as cloudy days for a solar panel Comparison of data collected from the same source at different times indicates soiling or degradation of the source with time or periodic events such as a moving shade from an adjacent building

Monitoring of Distributed Power Harvesting Systems Using DC Power Sources

Method for distributed power harvesting using DC power sources

A distributed power system including multiple DC power sources and multiple power modules. The power modules include inputs coupled respectively to the DC power sources and outputs coupled in series to form a serial string. An inverter is coupled to the serial string. The inverter converts power input from the serial string to output power. A signaling mechanism between the inverter and the power module is adapted for controlling operation of the power modules.

Safety mechanisms, wake up and shutdown methods in distributed power installations

A digital average-input current-mode control loop for a DC/DC power converter. The power converter may be, for example, a buck converter, boost converter, or cascaded buck-boost converter. The purpose of the proposed control loop is to set the average converter input current to the requested current. Controlling the average input current can be relevant for various applications such as power factor correction (PFC), photovoltaic converters, and more. The method is based on predicting the inductor current based on measuring the input voltage, the output voltage, and the inductor current. A fast cycle-by-cycle control loop may be implemented. The conversion method is described for three different modes. For each mode a different control loop is used to control the average input current, and the control loop for each of the different modes is described. Finally, the algorithm for switching between the modes is disclosed.

Digital Average Input Current Control in Power Converter

A photovoltaic system includes a plurality of photovoltaic modules and a DC motor connected to a three-phase generator driven by a shaft. The three-phase generator is connected to a power mains. The electric power supplied to the DC motor by the plurality of photovoltaic modules is repeatedly measured and adjusted, by changing an external excitation current of the DC motor, to the peak power attainable at the current ambient temperature and the current incident solar radiation intensity. The peak power is preferably determined by incrementally changing the excitation current in predetermined time intervals, until the supplied electric power produces a power level which can be regarded as the peak power.

Photovoltaic system and method for operating a photovoltaic system

The method involves providing a photovoltaic-system with a number of photovoltaic-modules. A direct current-motor is attached to one of the modules. The motor is connected with a three-phase generator by a shaft, where the generator is connected with a supply network system. Power supplied from the photovoltaic-modules to the motor is repeatedly measured. The power is adjusted to a power-peak value with controlled temperature and solar radiation by changing excitation of the motor.

Solar panel facility with electromechanical energy conversion

Die Photovoltaik-Anlage (1) besitzt eine Vielzahl von Photovoltaik-Modulen (5) und einen an die Photovoltaik-Module (5) angeschlossenen Gleichstrom-Motor (9), der uber eine Welle (13) mit einem Drehstrom-Generator (15) verbunden ist. Der Drehstrom-Generator (15) ist an ein Stromversorgungsnetz (17) angeschlossen. Die von den Photovoltaik-Modulen (5) an den Gleichstrom Motor (9) abgegebene Leistung (P) wird wiederholt gemessen, und die Leistung (P) wird uber eine Veranderung der Erregung (E) des Gleichstrom-Motors (9) auf denjenigen Leistungs-Hochstwert (MPP) eingestellt, derjeweils bei der herrschenden Temperatur und der herrschenden Sonneineinstrahlung moglich ist. Bevorzugt wird der Leistungs-Hochstwert (MPP) dadurch ermittelt, dass in zeitlich festgelegten Schritten (Δt) der Erregerstrom (E) incremental verandert wird, bis die jeweilige Messung der Leistung (P) einen Hochstwert ergibt, der als der zutreffende Leistungs-Hochstwert (MPP) angesehen wird.

Thomas Dipl.-Ing. Neussner

Papers

Photovoltaic system and method for operating a photovoltaic system

Solar panel facility with electromechanical energy conversion

Sonnenkollektoranlage mit elektromechanischer Energieumsetzung