Abstract: A power storage apparatus includes a storage battery chargeable and dischargeable, a voltage stepping-up/down circuit that performs a voltage stepping-up operation of stepping up by PWM control a voltage supplied from the storage battery and outputting a stepped-up voltage to a high-voltage DC bus line, and a voltage stepping-down operation of stepping down by PWM control a voltage supplied from the high-voltage DC bus line and supplying a stepped-down voltage to the storage battery. Moreover, a detection device is provided that outputs a detection signal indicating a full-charged state of the storage battery, and a controller keeps a high-side switch in the voltage stepping-up/down circuit in an off state in response to input of the detection signal.

Abstract: A battery module that includes a battery and a bidirectional DC-DC converter including a switching element that is arranged at a position where heat generated by the switching element is transmitted to the battery. The bidirectional DC-DC converter operates in a discharge mode in which DC power supplied from the battery is converted and supplied to an input/output unit, and in a charge mode in which DC power supplied from the input/output unit is converted and supplied to the battery. Moreover, a control unit forces the bidirectional DC-DC converter to operate in the discharge mode and to increase a switching frequency of the switching element in comparison with a switching frequency in normal driving, when a temperature in a periphery of the battery needs to be increased.

Abstract: A storage device that includes a first switching circuit connected to a direct-current voltage bus and a second switching circuit connected between the first switching circuit and a DC-DC converter. A smoothing capacitor is connected between the DC-DC converter and the switching circuit. Moreover, the second switching circuit includes a pair of relays connected in series between the first switching circuit and the DC-DC converter and an inrush current prevention circuit connected in parallel with the series circuit of the relays. A first voltage sensor is connected to a node between the pair of relays and a second voltage sensor is connected between both terminals of the smoothing capacitor. A control unit determines the presence of welding at the relays on the basis of voltage values detected by the voltage sensors.

Abstract: A power storage apparatus includes a charge and discharge controller. To start a voltage increasing operation in a state where a smoothing capacitor is not charged, the charge and discharge controller supplies a nonrestrictive current to a voltage increasing and decreasing circuit after charging the smoothing capacitor with a restrictive current. When a second direct-current voltage is supplied to a second terminal, the charge and discharge controller charges the smoothing capacitor with an increased voltage by the voltage increasing operation after charging the smoothing capacitor with the restrictive current, reduces a potential difference between the charge voltage in the smoothing capacitor and the second direct-current voltage, and then closes a switch circuit.

Abstract: A battery module that includes a battery and a bidirectional DC-DC converter including a switching element that is arranged at a position where heat generated by the switching element is transmitted to the battery. The bidirectional DC-DC converter operates in a discharge mode in which DC power supplied from the battery is converted and supplied to an input/output unit, and in a charge mode in which DC power supplied from the input/output unit is converted and supplied to the battery. Moreover, a control unit forces the bidirectional DC-DC converter to operate in the discharge mode and to increase a switching frequency of the switching element in comparison with a switching frequency in normal driving, when a temperature in a periphery of the battery needs to be increased.

Abstract: A storage device that includes a first switching circuit connected to a direct-current voltage bus and a second switching circuit connected between the first switching circuit and a DC-DC converter. A smoothing capacitor is connected between the DC-DC converter and the switching circuit. Moreover, the second switching circuit includes a pair of relays connected in series between the first switching circuit and the DC-DC converter and an inrush current prevention circuit connected in parallel with the series circuit of the relays. A first voltage sensor is connected to a node between the pair of relays and a second voltage sensor is connected between both terminals of the smoothing capacitor. A control unit determines the presence of welding at the relays on the basis of voltage values detected by the voltage sensors.

Abstract: A power storage apparatus includes a storage battery chargeable and dischargeable, a voltage stepping-up/down circuit that performs a voltage stepping-up operation of stepping up by PWM control a voltage supplied from the storage battery and outputting a stepped-up voltage to a high-voltage DC bus line, and a voltage stepping-down operation of stepping down by PWM control a voltage supplied from the high-voltage DC bus line and supplying a stepped-down voltage to the storage battery. Moreover, a detection device is provided that outputs a detection signal indicating a full-charged state of the storage battery, and a controller keeps a high-side switch in the voltage stepping-up/down circuit in an off state in response to input of the detection signal.

Abstract: A DC power supply system that limits the number of times of charging/discharging of the storage battery when a DC load is connected to a DC bus line. The system includes a DC bus line connectable to a DC load; a power generation device for supplying electric power to the DC bus line; a secondary battery for supplying electric power to the DC bus line; a DC-AC converter connected between the DC bus line and an AC power system; and a controller that controls power supply from the power generation device, the secondary battery, and the DC-AC converter to the DC bus line, and when the power supply of the power generation device cannot satisfy a power supply request of the DC load, the controller controls the DC-AC converter to supply electric power in preference to the secondary battery from the power system.

Abstract: A power storage apparatus includes a charge and discharge controller. To start a voltage increasing operation in a state where a smoothing capacitor is not charged, the charge and discharge controller supplies a nonrestrictive current to a voltage increasing and decreasing circuit after charging the smoothing capacitor with a restrictive current. When a second direct-current voltage is supplied to a second terminal, the charge and discharge controller charges the smoothing capacitor with an increased voltage by the voltage increasing operation after charging the smoothing capacitor with the restrictive current, reduces a potential difference between the charge voltage in the smoothing capacitor and the second direct-current voltage, and then closes a switch circuit.

Abstract: A DC power supply system that limits the number of times of charging/discharging of the storage battery when a DC load is connected to a DC bus line. The system includes a DC bus line connectable to a DC load; a power generation device for supplying electric power to the DC bus line; a secondary battery for supplying electric power to the DC bus line; a DC-AC converter connected between the DC bus line and an AC power system; and a controller that controls power supply from the power generation device, the secondary battery, and the DC-AC converter to the DC bus line, and when the power supply of the power generation device cannot satisfy a power supply request of the DC load, the controller controls the DC-AC converter to supply electric power in preference to the secondary battery from the power system.

Abstract: In a power converter that converts a direct-current voltage into three-phase alternating-current voltages and outputs the three-phase alternating-current voltages to a power system. The power converter includes a microprocessor that sets a dead time during which high-side switching elements and low-side switching elements are simultaneously off, and carries out switching. Moreover, the microprocessor performs dq transformation using complex numbers of phase currents, and detects an amplitude value of d-axis current or q-axis current. The microprocessor changes a phase difference to reduce the amplitude value of d-axis current or q-axis current. The microprocessor then performs dead-time compensation on the basis of the resulting phase difference.

Abstract: In a power converter that converts a direct-current voltage into three-phase alternating-current voltages and outputs the three-phase alternating-current voltages to a power system. The power converter includes a microprocessor that sets a dead time during which high-side switching elements and low-side switching elements are simultaneously off, and carries out switching. Moreover, the microprocessor performs dq transformation using complex numbers of phase currents, and detects an amplitude value of d-axis current or q-axis current. The microprocessor changes a phase difference to reduce the amplitude value of d-axis current or q-axis current. The microprocessor then performs dead-time compensation on the basis of the resulting phase difference.