Power supply device charging power storage device based on voltage comparison
The power supply device performs one-side charge control for controlling the system main relay, the charging relay, the series connection relay, the parallel connection relay, and the first and second neutral point relays so that only the first power storage unit is charged using the external DC power until the voltage of the first power storage unit becomes equal to or higher than the voltage of the second power storage unit before the first and second neutral point relays are turned on and the power storage device is charged using the external DC power.
1 . A power supply device configured to supply electric power to an inverter that includes a plurality of switching elements and a plurality of diodes connected in parallel in an opposite direction to the respective switching elements and that drives a three-phase alternating current motor, the power supply device comprising:
a power storage device that includes a first power storage unit and a second power storage unit;
a system main relay that includes
a positive-side relay attached to a positive-side line of a power line that connects between the power storage device and the inverter,
a negative-side relay attached to a negative-side line of the power line, and
a precharge circuit in parallel with the negative-side relay, the precharge circuit including a precharge resistor connected in series with a precharge relay;
a first capacitor attached to the power line;
a direct current charging device that includes
a charging power line that connects between an external charging connector, to which external direct current power is supplied, and a portion of the power line between the system main relay and the inverter,
a charging relay attached to the charging power line,
a series connection line that connects the first power storage unit and the second power storage unit in series,
a series connection relay attached to the series connection line,
a parallel connection line that connects between a portion of the series connection line on the first power storage unit side with respect to the series connection relay and a portion of the negative-side line of the power line on the second power storage unit side with respect to the negative-side relay and the precharge circuit,
a parallel connection relay attached to the parallel connection line,
a neutral point line that connects between a neutral point of the three-phase alternating current motor and a portion of the series connection line on the second power storage unit side with respect to the series connection relay,
a first neutral point relay attached to the neutral point line,
a second neutral point relay attached to a portion of the neutral point line on the second power storage unit side with respect to the first neutral point relay, and
a second capacitor attached between a portion of the neutral point line between the first neutral point relay and the second neutral point relay and a portion of the negative-side line of the power line on the inverter side with respect to the negative-side relay and the precharge circuit;
a first voltage sensor configured to detect a first voltage value of the first capacitor;
a second voltage sensor configured to detect a second voltage value of the second capacitor; and
a processor configured to execute following processes in the order of (i) to (viii) to charge the power storage device using the external direct current power:
(i) turning off the system main relay, the charging relay, the series connection relay, the parallel connection relay, the first neutral point relay, and the second neutral point relay,
(ii) turning on the parallel connection relay, the positive-side relay, and the second neutral point relay,
(iii) turning on the precharge relay,
(iv) acquiring the detected first voltage value from the first voltage sensor and the detected second voltage value from the second voltage sensor,
(v) comparing the detected first voltage value and the detected second voltage value,
(vi) turning on the charging relay in a case where the detected first voltage value is less than the detected second voltage value,
(vii) repeating the processes (iv) and (v), and
(viii) turning on the negative-side relay and the first neutral point relay and turning off the precharge relay in a case where the detected first voltage value is equal to or higher than the detected second voltage value.
2 . The power supply device according to claim 1 , wherein the processor is further configured to
turn on the charging relay,
compare an external voltage value of the external direct current power and a rated voltage value of the first power storage unit in combination with the second power storage unit in series, and
execute the processes (i) to (viii) in a case where the external voltage value is 0.5 times the rated voltage value.