Power conversion system

A power conversion system comprising:

• one first power conversion device connected between a first power supply and a load;
• and one or more second power conversion devices connected between a second power supply and the load in parallel with the first power conversion device, wherein
• the first power conversion device includes:
• a first power converting circuitry to control output voltage to be a preset voltage to apply the preset voltage to the load on the basis of an output from the first power supply;
• and
• a first voltage detecting circuitry to detect a first voltage, the first voltage being voltage at a connection point of the first power converting circuitry and the load,
• the first power conversion device controls operation of the first power converting circuitry so that a detected value of the first voltage detected by the first voltage detecting circuitry becomes a preset voltage value,
• the one or more second power conversion devices include:
• a second power converting circuitry to control output current to be a preset current to supply the preset current to the load on the basis of an output from the second power supply,
• the one or more second power conversion devices control operation of the second power converting circuitry on the basis of the detected value of the first voltage,
• the first power conversion device stops operation of the second power converting circuitry by changing the first voltage,
• the first power conversion device is a power conversion device being interconnectable with a commercial power supply,
• the first power conversion device has a determination value for determining abnormality of the commercial power supply at the first voltage when interconnecting with the commercial power,
• the first power conversion device determines a change amount of one or more of an effective value, a frequency, a phase, and a harmonic wave of the first voltage on the basis of the determination value, and
• wherein when changing the first voltage periodically, the first power conversion device determines at least one of a time during which the first voltage is changed and a time during which the first voltage is not changed on the basis of a settling time used for determination of abnormality of the first voltage.

A power conversion system comprising:

• one first power conversion device connected between a first power supply and a load;
• and one or more second power conversion devices connected between a second power supply and the load in parallel with the first power conversion device, wherein
• the first power conversion device includes:
• a first power converting circuitry to control output voltage to be a preset voltage to apply the preset voltage to the load on the basis of an output from the first power supply;
• and
• a first voltage detecting circuitry to detect a first voltage, the first voltage being voltage at a connection point of the first power converting circuitry and the load,
• the first power conversion device controls operation of the first power converting circuitry so that a detected value of the first voltage detected by the first voltage detecting circuitry becomes a preset voltage value,
• the one or more second power conversion devices include:
• a second power converting circuitry to control output current to be a preset current to supply the preset current to the load on the basis of an output from the second power supply,
• the one or more second power conversion devices control operation of the second power converting circuitry on the basis of the detected value of the first voltage,
• the first power conversion device stops operation of the second power converting circuitry by changing the first voltage,
• when changing the first voltage, the first power conversion device periodically changes the first voltage, and
• wherein when changing the first voltage periodically, the first power conversion device determines at least one of a time during which the first voltage is changed and a time during which the first voltage is not changed on the basis of a settling time used for determination of abnormality of the first voltage.

A power conversion system comprising:

• one first power conversion device connected between a first power supply and a load;
• and one or more second power conversion devices connected between a second power supply and the load in parallel with the first power conversion device, wherein
• the first power conversion device includes:
• a first power converting circuitry to control output voltage to be a preset voltage to apply the preset voltage to the load on the basis of an output from the first power supply;
• and
• a first voltage detecting circuitry to detect a first voltage, the first voltage being voltage at a connection point of the first power converting circuitry and the load,
• the first power conversion device controls operation of the first power converting circuitry so that a detected value of the first voltage detected by the first voltage detecting circuitry becomes a preset voltage value,
• the one or more second power conversion devices include:
• a second power converting circuitry to control output current to be a preset current to supply the preset current to the load on the basis of an output from the second power supply,
• the one or more second power conversion devices control operation of the second power converting circuitry on the basis of the detected value of the first voltage,
• the first power conversion device stops operation of the second power converting circuitry by changing the first voltage,
• the first power converting circuitry converts direct-current power into alternating-current power on the basis of the output from the first power supply and supplies the alternating-current power to the load,
• the first power conversion device changes one or more of an effective value, a frequency, a phase and a harmonic wave of the first voltage,
• the first power conversion device is a power conversion device interconnectable with a commercial power supply, and
• when changing the frequency of the first voltage, the first power conversion device determines a change amount by which the frequency of the first voltage is to be changed on the basis of the frequency of the commercial power supply;
• and
• wherein when changing the first voltage periodically, the first power conversion device determines at least one of a time during which the first voltage is changed and a time during which the first voltage is not changed on the basis of a settling time used for determination of abnormality of the first voltage.