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

An active current sharing circuit that provides a plurality of paralleled DC-DC converters each having a lossless inductor-based current sensing circuit for sensing the average current of the associated DC-DC converter through its output inductor, and a means for adjusting the voltage reference coupled to each of the DC-DC converter's PWM controllers through a one pin interconnection between the converters. The circuit provides a high percentage current sharing level at lower cost, with reduced circuit wiring complexity, and fewer components. In an alternate embodiment, the inductor-based current sensing is replaced with a resistor-based current sensing, such that comparable current sharing levels are achieved albeit with higher loss.

Active current sharing circuit

The present invention is of a glow discharge switch operating in the low pressure regime where gas breakdown is limited by the distance between electron-gas particle collisions (pseudospark discharge). The invention utilizes linear discharge apertures (length greater than width) in the electrodes. The linear apertures provide significantly higher current conduction without discharge constriction than conventional round-hole pseudospark switches. A radial version of the linear pseudospark switch also is disclosed that provides for self-canceling of the magnetic fields induced by the discharge, and thus prevents discharge constriction and provides for very high current conduction.

Linear aperture pseudospark switch

A method for optimizing operation of a feedback system may include generating a control signal according to a control parameter, regulating an output of the feedback system via the control signal, and monitoring the control parameter. In response to the monitoring indicating that the present value of the control parameter is outside a specific range of values, a first parameter that impacts an operating characteristic of the feedback system may be adjusted until the present value of the control parameter is within the specific range of values. The specific range of values of the control parameter may correspond to a target level of the operating characteristic of the feedback system with respect to the first parameter. One or more additional independent parameters also impacting the operating characteristic of the system may be similarly adjusted to obtain a minimum present value of the control parameter at which the output of the feedback system would be regulated, with the minimum value of the control parameter corresponding to the target level of the operating characteristic of the feedback system with respect to, collectively, the first parameter and the one or more additional independent parameters.

Control system optimization via independent parameter adjustment

A circuit that efficiently prevents the turning on of the synchronous rectifier in a buck converter during a predetermined condition, so as to prevent current reversing through the synchronous rectifier during that time. In one embodiment, the circuit provides control of the synchronous rectifier during the soft-start time for a non-isolated DC-DC buck converter, thereby preventing current reversing (sinking), referred to as the back bias condition, during its soft start process. In another embodiment, a circuit uses a signal indicative of a soft-start condition for a converter to prevent the turning on of the synchronous rectifier during the soft-start time. A corresponding system solves the aforementioned synchronous rectifier back bias problem for converters used in a paralleled converter configuration.

Soft-start with back bias conditions for PWM buck converter with synchronous rectifier

A single-cycle charge regulator (SCCR) may be used in operating a power converter at a constant frequency without requiring compensation The SCCR may include a first control loop to generate an error value based on the output voltage of the power converter and a reference voltage, and to generate a first control value based on the error value to control steady-state behavior of the output of the power converter A second control loop may generate a second control value based on the error value, to regulate response of the power converter to a transient deviation on the output voltage A third control loop may operate to adjust a current (affected by the output voltage of the the power converter) subsequent to the transient deviation, according to a third control value derived from previous values of the first control value, the second control value, and the third control value, to keep the adjusted current commensurate with the current that was present prior to the transient deviation, while keeping the output voltage of the power converter at its desired steady-state value

Chris M. Young

Papers

Active current sharing circuit

Linear aperture pseudospark switch

Control system optimization via independent parameter adjustment

Soft-start with back bias conditions for PWM buck converter with synchronous rectifier

Single-cycle charge regulator for digital control