Electrical power source, operational method of the same, inverter and operational method of the same

An inverter in which an equivalent output impedance is a resistance value expressed by (1−β*G)/(α*G) when α is an output voltage feedback gain, β is an output current feed forward gain, and G is an inverter current gain, wherein

• the inverter changes the equivalent output impedance by adjusting both or either one of the output voltage feedback gain α or the output current feed forward gain β,
• the equivalent output impedance of the inverter prior to start feeding of power is set to be a first set value that limits an output current to be a desired value or below by changing the equivalent output impedance by adjusting both or either one of the output voltage feedback gain α or the output current feed forward gain β;
• and
• the equivalent output impedance of the inverter is decreased after starting feeding of power to be a second set value that is smaller than the first set value.

An inverter in which an equivalent output impedance is a resistance value expressed by (1−β*G)/(α*G) when α is an output voltage feedback gain, β is an output current feed forward gain, and G is an inverter current gain, wherein

• the inverter changes the equivalent output impedance by adjusting both or either one of the output voltage feedback gain α or the output current feed forward gain β,
• the equivalent output impedance is set to be a first set value that limits an output current to be a desired value or below;
• the inverter is connected in parallel to another inverter without synchronism, or is connected to a commercial AC electrical power system;
• an output voltage of the inverter is synchronized with an output voltage of said another inverter or to an voltage of the commercial AC electrical power system without performing synchronism;
• and
• the equivalent output impedance of the inverter is changed to a second set value that is smaller than the first set value.