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 novel life-cycle monitoring and voltage-managing device for dc-link electrolytic capacitors in pulsewidth modulation converters is presented. The system performs online identification of the capacitor's equivalent series resistance (ESR) in order to detect the life-cycle status and permit preventive maintenance. The ESR detection is based on the capacitor's ac losses calculated from voltage/current measurements using a simple low-cost microcontroller. The unit is designed as small printed circuit board located directly at the capacitor's screw terminals in order to simplify the required temperature sensing and to minimize wiring effort. The minimized energy consumption allows a power supply taken out of the capacitor to be tested. Besides life-cycle monitoring, the unit further facilitates energy-efficient voltage balancing for capacitors in series arrangements avoiding any power resistors typically used in balancing circuits. Instead, the unit controls the capacitor voltage by influencing its power consumption. Each individual monitoring unit (one per each power capacitor of the converter) transfers the ESR results to the converter's main controller and receives control commands via a common optoisolated fieldbus. Alternatively, this data transfer is performed using wireless near-field communication leading to a completely autonomous monitoring unit without any wiring for power supply and data transmission.

Life-Cycle Monitoring and Voltage-Managing Unit for DC-Link Electrolytic Capacitors in PWM Converters

The continuing trend toward greater electrification and control of functions in consumer, commercial, industrial, transportation, and even medical applications promises a dynamic and increasingly important role for power electronics. The growing penetration of power electronics in energy systems is driven by new materials such as SiC and GaN, as well as new packaging technologies which allow the physical integration of electronics with powered and controlled devices such as motors. Advances in very high-frequency conversion led by the application of SiC and GaN devices promises to make converter-on-a-chip technology possible, but concurrent advances in passive component technology are necessary. The principal challenge to application penetration remains cost reduction.

Evolving and Emerging Applications of Power Electronics in Systems

This paper presents a low-cost method to realize a real-time condition monitoring and a predictive-maintenance system of an electrolytic capacitor used in uninterruptible power supplies (UPSs). This method consists in detecting the changes in real time of the equivalent series resistance and the capacitance C values of the electrolytic capacitors. Simulation and experimental results are presented to illustrate the proposed monitoring technique. The proposed method can be used in UPS where waveforms are continuously varying in amplitude, frequency, and temperature. The proposed online failure prediction method has the merits of using only the existent resources in UPS and with the use of known algorithms.

https://hal.archives-ouvertes.fr/hal-00536644/document

A Real-Time Predictive-Maintenance System of Aluminum Electrolytic Capacitors Used in Uninterrupted Power Supplies

A method and device for predicting defects of a capacitor, the method including determining the ripple voltage (Udc), the temperature (TP), and the current (Ic) of the capacitor, determining the value of an equivalent series resistance (ESR) of the capacitor, and the capacitance value (C) of the capacitor using a digital filter, determining information representative of the state of aging of the capacitor according to the temperature of the capacitor, and displaying that information and information representative of the value of the capacitance (C) and/or information representative of a cause associated with the state of aging according to the capacitance value. The device may include a converter and an uninterruptible power supply.

Method and device for predicting electrolytic capacitor defects, converter and uninterruptible power supply equipped with such a device

This paper presents a low cost method to realize a real time condition monitoring and a predictive maintenance system of an electrolytic capacitor used in uninterrupted power supplies (UPS). This method consists in detecting the changes on real time in equivalent series resistance (ESR) and the capacitance C values of the electrolytic capacitors. Simulation and experimental results are presented to illustrate the proposed monitoring technique. The proposed method can be used in UPS where waveforms are continuously varying in amplitude, frequency and versus temperature. The proposed on line failure prediction method has the merits of using only the existent resources in UPS and with the use of knower algorithms.

https://hal.archives-ouvertes.fr/hal-00369572/document

A Real Time Predictive Maintenance System of Aluminium Electrolytic Capacitors Used in Uninterrupted Power Supplies

This paper presents a work used for a low cost method to create a real time condition monitoring and a predictive maintenance system of an electrolytic capacitor in Uninterrupted Power Supplies (UPS). It consists of evaluating the evolution laws for equivalent series resistance (ESR) and the capacitance C values of the electrolytic capacitors versus operating time. Experimental results of parameter evolutions and the law estimations are presented. The laws funded are used in UPS where waveforms are contin­uously varying in amplitude, frequency and versus temperature. The estimated laws are used for the on line failure prediction method which has the merits of using only the existent resources in UPS.

https://hal.archives-ouvertes.fr/hal-00475767/document

Online monitoring method and electrical parameter ageing laws of aluminium electrolytic capacitors used in UPS

The electrolytic capacitor usually has the shortest span of life in the power converter. This paper presents a new low cost implementation of a real time condition monitoring and a predictive maintenance system of an electrolytic capacitor used in Uninterruptible Power Supplies (UPS). It consists of detecting the changes in real time in equivalent series resistance (ESR) and the capacitance C values of the electrolytic capacitors. The proposed method can be used in UPS where waveforms are continuously varying in amplitude, frequency and versus ambient temperature. This method has the merits of using known algorithms and only the existent resources in UPS.

Christophe Rosset

Papers

A Real-Time Predictive-Maintenance System of Aluminum Electrolytic Capacitors Used in Uninterrupted Power Supplies

Method and device for predicting electrolytic capacitor defects, converter and uninterruptible power supply equipped with such a device

A Real Time Predictive Maintenance System of Aluminium Electrolytic Capacitors Used in Uninterrupted Power Supplies

Online monitoring method and electrical parameter ageing laws of aluminium electrolytic capacitors used in UPS

Kalman filter used for on line monitoring and predictive maintenance system of aluminium electrolytic capacitors in UPS