Omron Corporation

Tokyo Institute of Technology

Yasuhiro Tsubota

Masao Mabuchi

Takao Mizokami

Kenji Kobayashi

Nobuyuki Toyoura

Katsuya Marumo

Hideaki Fujita

Kazumi Tsuchimichi

Katsutaka Tanabe

Kazuyoshi Imamura

Hideki Kobori

Kotaro Nakamura

Masashi Isozumi

Takashi Horie

Tsunetoshi Ooba

Haruyasu Murabayashi

Takatoshi Ootomo

Akihiro Funamoto

Junichiro Yamada

Tetsuya Yamamoto

Shinichi Hosomi

Takuya Nakai

Teruyuki Maeda

Mio Yamada

Katsumi Ohashi

Hajimu Iwai

Seiji Oka

Kunio Aono

Takuji Kumagai

Naoki Maki

Atsuo Minato

Tomoya Irie

Mike Irvin

Theo Brusse

Hiroto Takashiro

Hiroshi Kusakabe

Shinobu Wada

Katsuhiko Ohno

Hirokazu Ehara

Masaya Kato

Arata Yoneda

A converter is configured for connecting between a solar cell and an inverter configured to convert direct-current power output from the solar cell into alternating current power, and the converter is configured to increase the potential-to-ground at the negative terminal of the solar cell to greater than the potential-to-ground at the negative terminal of the inverter when outputting the direct-current power generated by the solar cell to the inverter side.

Solar power system and converter

A technology for suppressing a performance degradation of a solar battery caused by PID is provided. A conversion device includes a DC/DC converter and a control part. A solar battery is connected to an input end of the DC/DC converter. When direct-current power generated by the solar battery is converted and output, the DC/DC converter makes a potential of a negative electrode of the solar battery to be higher than a potential in a negative electrode of the output when the power input from the solar battery exceeds a prescribed value. The control part changes a voltage of the power output from the solar battery to detect a peak value of the power, and stops the operation of the DC/DC converter when the peak value is smaller than the prescribed value.

Conversion device and hybrid power supply system

A power supply system for recovering degraded performance of a solar cell due to PID is provided. The power supply system includes a solar cell, a non-isolated type DC/DC converter that boosts a DC voltage from the solar cell input from an input end with a predetermined boosting ratio and outputs a DC voltage from an output end, and an inverter that converts a DC voltage output from the output end of the DC/DC converter into an AC voltage, the power supply system being connected to an external power system for system interconnection, wherein the power supply system includes a potential adjustment device for applying a voltage of an external power system to the solar cell via the inverter to set a ground potential of a negative electrode of the solar cell to positive when an output of the solar cell is smaller than a predetermined value.

Power supply system, DC/DC converter, and power conditioner for suppressing performance degradation in solar cells

A voltage transform part transforms the direct-current power input to an input part. A first input and output part outputs the transformed direct-current power to a battery unit and to which direct-current power is input from the battery unit. A conversion part converts the direct-current power input to the input part into alternating-current power. A second input and output part outputs the alternating-current power to a power system or a load and to which an alternating-current power is input from the power system. The conversion part converts the alternating-current power input to the second input and output part into direct-current power. The second voltage transform part transforms the direct-current power converted by the conversion part and transforms the direct-current power input to the first input and output part. The conversion part converts the direct-current power transformed by the second voltage transform part into alternating-current power.

Power storage system, voltage transformer and power storage power conditioner

A distributed power system that is connected to a utility grid during both daytime and nighttime includes a plurality of power supplies including a solar array, a non-isolated DC-DC converter that has an input terminal and an output terminal and raises, at a predetermined step-up ratio, a DC voltage input from the power supplies via the input terminal and outputs the DC voltage via the output terminal, an inverter that converts the DC voltage output from the DC-DC converter via the output terminal into an alternating current, and a potential adjustment section that adjusts a potential at a negative electrode of the solar array to a potential higher than a potential at a negative electrode of the inverter at least during nighttime.

Distributed power system, DC-DC converter, and power conditioner

Battery

An inverter apparatus comprising a first switch group that is connected to a DC power source and includes a first switch and a second switch connected in series; a capacitor that has one end thereof connected to a first connection point between the first switch and the second switch; a second switch group that is connected in parallel with the capacitor and includes a third switch and a fourth switch that are connected in series; a switch control section that controls an ON/OFF state of the first switch, the second switch, the third switch, and the fourth switch to convert DC voltage from the DC power source into AC voltage and output the AC voltage from a second connection point between the third switch and the fourth switch; and a smoothing circuit that is connected to the second connection point and normalizes a pulse waveform of the AC voltage.

Inverter apparatus and solar power generation system

A power conditioner that suppresses distortion in a waveform of a sinusoidal generated voltage includes a first and second group including two switches each connected in inverse parallel and in series. The power conditioner alternately turns on and off both switches in the first group at a prescribed chopping frequency and alternately turns on and off both switches in the second group at a PWM frequency higher than the chopping frequency. If control is performed with a dead-time provided in the on/off timing for both switches in each group, the power conditioner adjusts and controls the on/off duty for the second group switches to correspond to the effective on drive in one switch by each diode during the dead-time for each switch in the first group.

Power conditioner

A power conditioner that suppresses generation of voltage spikes in a part of a generated sinusoidal voltage waveform. An offset between the timing of chopping, which depends on whether the voltage difference between the voltage of a third pulse voltage series and a sinusoidal voltage is positive or negative, and the timing of the switching between on/off duty cycles of a seventh and eighth switch is calculated, and the on/off duty cycles of the seventh and eighth switches are controlled on the basis of the timing offset.

A first circuit generates a first sequence of square wave voltages having a voltage level that changes to a positive side relative to a first reference potential, which is a potential on a negative-electrode side of a direct current power source, from a direct current voltage. A second circuit generates a second sequence of square wave voltages having a voltage level lower than the voltage level of the first sequence of square wave voltages on the positive side that changes to a negative side relative to a second reference potential. The second chopper circuit further generates a third sequence of square wave voltages having a voltage level that changes to the positive and negative side in turns in the manner of sinusoidal wave relative to the first reference potential by summing the first sequence of square wave voltages and the second sequence of square wave voltages. A third circuit outputs the third sequence of square wave voltages as a charge/discharge output. The third circuit further PWM-controls the charge/discharge output so that a difference of the third sequence of square wave voltages to a sinusoidal wave voltage is corrected and thereby generates a sinusoidal wave voltage that continuously changes to the positive and negative sides relative to the first reference potential from the third sequence of square wave voltages and the PWM-controlled output, and outputs the generated sinusoidal wave voltage to a load.

Power conditioner and solar photovoltaic power generation system

A first chopper circuit generates a first sequence of square wave voltages having a voltage level that changes to a positive side by chopping a direct current voltage at a system frequency. A second chopper circuit generates a second sequence of square wave voltages having a voltage level that changes to a negative side by chopping a direct current voltage at a frequency twice as high as the system frequency. The second chopper circuit further generates a third sequence of square wave voltages having a voltage level that changes to the positive and negative side in turns in the manner of sinusoidal wave by summing the first sequence of square wave voltages and the second sequence of square wave voltages. A third chopper circuit chops the third sequence of square wave voltages at a frequency determined by a timing that depends on if a voltage difference thereof to a sinusoidal wave voltage results in a positive value or a negative value and outputting the chopped third sequence of square wave voltages as a charge/discharge output. The third chopper circuit PWM-controls the charge/discharge output at a PWM frequency so that the difference is corrected to thereby generate a sinusoidal wave voltage that continuously changes to the positive and negative sides.

Power conversion apparatus, power conditioner, and power generation system

An isolated operation detecting method according to the present invention includes: a first step that injects a power fluctuation into the power system; a second step that measures a system cycle; a third step that adjusts the injection of the power fluctuation so that the system cycle increases when the system cycle is found increased than the previous system cycle as a result of the measuring, and decreases when the system cycle is found decreased than the previous system cycle; a fourth step that produces a change pattern of a latest system cycle on the basis of a deviation of the latest system cycle from a fixed number of cycle-passed previous system cycle; and a fifth step that determines an isolated operation on the basis of the change pattern.

Isolated operation detecting method, control apparatus for detecting isolated operation for distributed power supply

A direct current detection circuit has a zero-phase current transformer with source lines inserted therethrough for detecting current differences among them and generates a comparison voltage value based on a divided voltage value obtained between the zero-phase current transformer and a voltage divider resistor according to a change in the self-impedance of the zero-phase current transformer. An offset current is passed through the zero-phase current transformer to make it possible to detect on the basis of the comparison voltage value a direct current value in a range which is otherwise difficult to detect accurately on the basis of the comparison voltage value because of influence of hysteresis characteristic of the zero-phase current transformer. A control circuit detects a present direct current value based on the comparison voltage value and the value of the offset current.

Direct current detection circuit

A power source apparatus with a saving in wiring, large noise immunity and an additional function is achieved by connecting AC input bus lines (Vin+), (Vin&#x2212;), DC output bus lines (Vo+), (Vo&#x2212;) and a current balance signal bus line (CB) for connecting first, second, third power source unitsthrough connectors to form a module power source and connecting an additional function unitfor adding a predetermined additional function to the module power source using the bus lines to this module power source through a connector.

Power source apparatus

The invention has a first series circuit consisting of a capacitor and a diode and a second series circuit consisting of a coil and a diode, the first series circuit is connected in parallel to the commutating diode in a state that the capacitor is connected to a choke coil side in the commutating diode, and the second series circuit is connected between a connecting portion of the capacitor and the diode in the first series circuit and a commutating diode non-connecting side in the choke coil.

Snubber circuit and power transformer using the same

Growing community of inventors

Moriyama, Japan

Yasuhiro Tsubota