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

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 distributed power system wherein a plurality of power converters are connected in parallel and share the power conversion load according to a prescribed function, but each power converter autonomously determines its share of power conversion Each power converter operates according to its own power conversion formula/function, such that overall the parallel-connected converters share the power conversion load in a predetermined manner

Parallel connected inverters

PROBLEM TO BE SOLVED: To make it possible to detect when snow has been melted at a preset value or above, by stopping a power conditioner for a short time at constant time interval, or stopping the power conditioner when the power conditioner is brought into constant current control state, and checking the output voltage from solar cell power generation. SOLUTION: A power conditioner 61 pauses at constant time intervals, or at constant timer intervals after the power conditioner is brought out of constant voltage control state. That is, if a voltage equal to or above a preset value, it is judged that snow has been melted. Then, the power conditioner 61 is stopped, and switched to the power generation side. If the generation voltage is lower than the set value, the power conditioner 61 is restarted and directcurrent power is supplied. Thus, it is possible to let reverse power flow perform through solar cell generation when the sun is shining, and bring the power conditioner in forward conversion operation to melt snow through temperature rise in the solar cell when it is snowing or the snow lies. COPYRIGHT: (C)1998,JPO

Control method for snow-melting device using solar cell

PURPOSE:To prevent the operating voltage from being largely apart from a maximum power point by dispensing with control of the maximum power pint and keeping the operating voltage in an unchanged state if generated power is changed by the change of the solar radiation quantity while judging the change cause of the generated power. CONSTITUTION:A measuring device 4 measures the power generated by a solar battery 1 and stores the measured values in a memory device 5. A control circuit 3 decides whether the generated power is changed by the change of the operating voltage or the change of the solar radiation quantity. When the change of the solar radiation quantity is performed, a power converter 2 is instructed to dispense with tracking control of the maximum power point, and the maximum power point tracking control is performed only when the solar radiation is stable. That is, all the measured values of the measurement value W1 set before the change of the operating voltage, the measurement value W2 set after the change of the operating voltage, and the measurement value W3 set when the changed operating voltage before the change is restored are stored and then compared with each other. Then the operating voltage before the change is kept when W1 W2 and W2>W3 are satisfied respectively.

Maximum power point tracking control method for solar battery

PROBLEM TO BE SOLVED: To provide an uninterruptible power supply device that enhances the reliability of power supply in the event of a power outage while implementing overdischarge protection of a storage battery.SOLUTION: A UPS 10 includes: a rectifier 14 for converting AC power to DC power; a battery unit 36 charged with the DC power from the rectifier 14; and an inverter unit 18 for converting the DC power from the battery unit 36 to AC power in the event of a power outage. The UPS 10 further includes an electromagnetic switch 40 arranged in a charging path from the rectifier 14 to the battery unit 36, and a circuit breaker 34 arranged in a discharging path from the battery unit 36 to the inverter unit 18. A battery state detection circuit 46 opens the electromagnetic switch 40 when a cell voltage of a single cell exceeds a charge end threshold, and outputs a trip signal to the circuit breaker 34 to cause the circuit breaker 34 to perform a breaking action when detecting an anomaly in the single cell.

Uninterruptible power supply device and power supply device

A storage unit connection information acquisition apparatus capable of suppressing an excessive cross current from flowing when connecting a plurality of storage units in parallel is provided. A storage unit connection information acquisition device for acquiring information for connecting in parallel a plurality of power storage units having one or more power storage elements connected in series, wherein A connectable range acquisition unit 110 that acquires the connectable range by determining a connectable range that is a range of the power storage units 200 that can be connected in parallel, and a connection in which the power storage units 200 within the connectable range are connected in parallel The power storage unit group includes a charge / discharge information acquisition unit 120 that acquires information for charging or discharging the connected power storage unit group so that the power storage units 200 outside the connectable range can be connected in parallel. [Selection] Figure 2

Ichio Kawarabayashi

Papers

Control method for snow-melting device using solar cell

Maximum power point tracking control method for solar battery

Uninterruptible power supply device and power supply device

Connection information acquisition device for power storage units