Power storage control apparatus, direct-current power system, and controlling method thereof

A direct-current power system, comprising:

• a direct-current power generation apparatus;
• a load apparatus that converts or consumes power generated by the direct-current power generation apparatus;
• a power line connecting the direct-current power generation apparatus and the load apparatus to each other;
• a diode electrically connected to the power line, and that prevents current supplied by the direct-current power generation apparatus from flowing in a reverse direction of a direction in which the current flows;
• a power line interface electrically connected to the power line;
• a bidirectional DC-DC converter electrically connected to the power line interface and a battery;
• a first current sensor that measures a first current value of direct current outputted from the bidirectional DC-DC converter;
• a second current sensor that measures a second current value of direct current of the power line;
• a voltage sensor that measures a first voltage value of the power line interface;
• the battery;
• and
• a controller that receives the first current value measured by the first current sensor and a current command value and performs constant current control processing that controls the bidirectional DC-DC converter so that the first current value equals the current command value, wherein
• the controller receives the first voltage value measured by the voltage sensor and a voltage command value and performs constant voltage control processing that controls the bidirectional DC-DC converter so that the first voltage value equals the voltage command value, wherein
• the controller switches operation from the constant current control processing to the constant voltage control processing.

A controlling method of a direct-current power system including a direct-current power generation apparatus, a load apparatus that converts or consumes power generated by the direct-current power generation apparatus, a power line connecting the direct-current power generation apparatus and the load apparatus to each other, and a diode provided to the power line, and that prevents current supplied by the direct-current power generation apparatus from flowing in a reverse direction of a direction in which the current flows, comprising:

• measuring a first current value of direct current outputted from a bidirectional DC-DC converter electrically connected to the power line interface and a battery;
• measuring a second current value of direct current of the power line;
• measuring a first voltage value of the power line;
• receiving a current command value;
• receiving a voltage command value;
• controlling the bidirectional DC-DC converter so that the first current value of the bidirectional DC-DC converter equals the current command value;
• and
• controlling the bidirectional DC-DC converter so that the first voltage value equals the voltage command value, if the first current value of the bidirectional DC-DC converter equals the current command value.