Abstract: A main circuit power supply device includes: a plurality of voltage-division power storage elements connected in series; voltage adjustment circuits for adjusting each of voltages of the plurality of voltage-division power storage elements through mutual transfer of power between the plurality of voltage-division power storage elements; and at least one DC/DC converter which is connected to at least one of the voltage-division power storage elements and supplies a control power source to a main circuit control circuitry to control a main circuit.

Abstract: Each of a plurality of unit converters includes: a main circuit; a control circuit that controls the plurality of switching elements according to a control signal received from the controller; a power supply that lowers a voltage of a first capacitor to generate a power supply voltage and supplies the power supply voltage to the control circuit; and a current-limiting resistance circuit having a variable resistance value and disposed between the main circuit and the power supply. The power supply includes a second capacitor, an overcharge suppression circuit, a power supply circuit, and a controller. The controller includes: an overcharge suppression control circuit that controls the overcharge suppression circuit in accordance with a magnitude of a voltage of the second capacitor; and a resistance switching circuit that changes a resistance value of the current-limiting resistance circuit in accordance with a magnitude of a voltage of the first capacitor.

Abstract: A power supply includes a second capacitor, an overcharge suppression circuit, a power supply circuit, and a controller. The controller includes: an overcharge suppression control circuit that controls the overcharge suppression circuit in accordance with a magnitude of a voltage of the second capacitor; and a resistance switching circuit that changes a resistance value of the current-limiting resistance circuit depending on whether a gate block state occurs or not and in accordance with a magnitude of the voltage of the first capacitor. In the gate block state, each of the switching elements is fixed in a non-conductive state.

Abstract: A master converter and a plurality of slave converters each have an input connected to an associated one of a plurality of power storage elements, respectively, and an output connected to an output terminal in parallel. The master converter converts the voltage of the associated capacitor based on a duty ratio for matching an output voltage to a voltage command value, outputs the converted voltage to the output terminal, and transmits a control signal indicative of the duty ratio to the plurality of slave converters via a signal insulation unit. Each of the plurality of slave converters converts the voltage of the associated capacitor in response to the control signal transmitted via the signal insulation unit and outputs the converted voltage to the output terminal. A correction means is configured to correct at least the duty ratio in the master converter such that the duty ratio in the master converter matches the duty ratio in each of the plurality of slave converters.

Abstract: A main circuit power supply device includes: a plurality of voltage-division power storage elements connected in series; voltage adjustment circuits for adjusting each of voltages of the plurality of voltage-division power storage elements through mutual transfer of power between the plurality of voltage-division power storage elements; and at least one DC/DC converter which is connected to at least one of the voltage-division power storage elements and supplies a control power source to a main circuit control circuitry to control a main circuit.

Abstract: A power supply circuit is configured to convert a voltage of a second electricity storage element into a power supply voltage for a driving circuit, and a voltage detector is configured to detect the voltage of the second electricity storage element. A unit converter includes a first resistor connected to the second electricity storage element electrically in series between the terminals of a first electricity storage element, and a second resistor and a first switch connected electrically in series between the terminals of the second electricity storage element. The power supply circuit is configured to generate a control signal for controlling the first switch on and off based on the detection value from the voltage detector. The power supply circuit is further configured to sense an overloaded state of the second resistor based on the control signal.

Abstract: A power supply includes a second capacitor, an overcharge suppression circuit, a power supply circuit, and a controller. The controller includes: an overcharge suppression control circuit that controls the overcharge suppression circuit in accordance with a magnitude of a voltage of the second capacitor; and a resistance switching circuit that changes a resistance value of the current-limiting resistance circuit depending on whether a gate block state occurs or not and in accordance with a magnitude of the voltage of the first capacitor. In the gate block state, each of the switching elements is fixed in a non-conductive state.

Abstract: Each of a plurality of unit converters includes: a main circuit; a control circuit that controls the plurality of switching elements according to a control signal received from the controller; a power supply that lowers a voltage of a first capacitor to generate a power supply voltage and supplies the power supply voltage to the control circuit; and a current-limiting resistance circuit having a variable resistance value and disposed between the main circuit and the power supply. The power supply includes a second capacitor, an overcharge suppression circuit, a power supply circuit, and a controller. The controller includes: an overcharge suppression control circuit that controls the overcharge suppression circuit in accordance with a magnitude of a voltage of the second capacitor; and a resistance switching circuit that changes a resistance value of the current-limiting resistance circuit in accordance with a magnitude of a voltage of the first capacitor.

Abstract: A master converter and a plurality of slave converters each have an input connected to an associated one of a plurality of power storage elements, respectively, and an output connected to an output terminal in parallel. The master converter converts the voltage of the associated capacitor based on a duty ratio for matching an output voltage to a voltage command value, outputs the converted voltage to the output terminal, and transmits a control signal indicative of the duty ratio to the plurality of slave converters via a signal insulation unit. Each of the plurality of slave converters converts the voltage of the associated capacitor in response to the control signal transmitted via the signal insulation unit and outputs the converted voltage to the output terminal. A correction means is configured to correct at least the duty ratio in the master converter such that the duty ratio in the master converter matches the duty ratio in each of the plurality of slave converters.

Abstract: A power supply circuit is configured to convert a voltage of a second electricity storage element into a power supply voltage for a driving circuit, and a voltage detector is configured to detect the voltage of the second electricity storage element. A unit converter includes a first resistor connected to the second electricity storage element electrically in series between the terminals of a first electricity storage element, and a second resistor and a first switch connected electrically in series between the terminals of the second electricity storage element. The power supply circuit is configured to generate a control signal for controlling the first switch on and off based on the detection value from the voltage detector. The power supply circuit is further configured to sense an overloaded state of the second resistor based on the control signal.

Abstract: A control unit activates a power supply circuit when an input voltage becomes equal to or greater than a first threshold value. The control unit brings a switch into a conductive state when the input voltage becomes equal to or greater than a second threshold value and brings the switch into a non-conductive state when the input voltage becomes equal to or less than a third threshold value. The control unit deactivates the power supply circuit when the input voltage becomes equal to or less than a fourth threshold value. Based on the number of times that the input voltage becomes equal to or greater than the second threshold value after the power supply circuit is activated, the control unit further enables a latch function for holding the power supply circuit in a deactivated state.

Abstract: A control unit activates a power supply circuit when an input voltage becomes equal to or greater than a first threshold value. The control unit brings a switch into a conductive state when the input voltage becomes equal to or greater than a second threshold value and brings the switch into a non-conductive state when the input voltage becomes equal to or less than a third threshold value. The control unit deactivates the power supply circuit when the input voltage becomes equal to or less than a fourth threshold value. Based on the number of times that the input voltage becomes equal to or greater than the second threshold value after the power supply circuit is activated, the control unit further enables a latch function for holding the power supply circuit in a deactivated state.

Abstract: In a power conversion device, an inverter (10) of each of three arms (A1 to A3) is controlled such that circulating current (Iz) of three arms (A1 to A3) follows a reference (Izrt) in a test period (times t3 to t4) in which a power system (1) is cut off from the three arms (A1 to A3), and whether the power conversion device is normal is determined based on circulating current (Iz) in the test period. Whether the power conversion device is normal therefore can be determined without affecting the power system (1).

Abstract: A control device generates a voltage command value for controlling a current flowing between a three-phase AC power supply and a power converter such that a full voltage representative value representing voltage values of all power storage devices agrees with a DC voltage command value. The control device generates a zero-phase voltage command value for controlling a circulating current flowing in a delta connection such that the voltage values of the power storage devices are balanced among first to third arms. The control device combines the voltage command value and the zero-phase current command value to generate an output voltage command value for controlling an output voltage of each unit converter. The control device removes a control amount of the full voltage representative value from a computation of the zero-phase voltage command value to cause output current control and circulating current control not to interfere with each other.

Abstract: In the present power conversion device, when a fault occurs in a power system (1) and DC voltage (VDC) of a capacitor (15) included in a unit converter (5) exceeds a protection level (VH), the operation of an inverter (10) is stopped. When the DC voltage (VDC) decreases to a recovery level (V1) or lower, DC voltage control of the inverter (10) is resumed to quickly decrease the DC voltage (VDC). When the DC voltage (VDC) decreases to a recovery level (V2) or lower, reactive power control of the inverter (10) is resumed. Thus, even when a fault occurs in the power system (1), the operation of the inverter (10) can be quickly resumed.

Abstract: In the present power conversion device, when a fault occurs in a power system (1) and DC voltage (VDC) of a capacitor (15) included in a unit converter (5) exceeds a protection level (VH), the operation of an inverter (10) is stopped. When the DC voltage (VDC) decreases to a recovery level (V1) or lower, DC voltage control of the inverter (10) is resumed to quickly decrease the DC voltage (VDC). When the DC voltage (VDC) decreases to a recovery level (V2) or lower, reactive power control of the inverter (10) is resumed. Thus, even when a fault occurs in the power system (1), the operation of the inverter (10) can be quickly resumed.

Abstract: A power converter is electrically connected with an AC power supply via a switch, and is configured with a plurality of unit converters (5) connected in series. A drive circuit (40, 42) drives a plurality of switching elements (11 to 14) of a main circuit (30). An interface circuit (48) outputs a detection value of a voltage sensor (46) to a control device (4). If a bypass switch (7) is turned off when the power converter is activated, each of the plurality of unit converters (5) charges a capacitor (15) using power supplied from the AC power supply. When the power converter is activated, a power supply (50) supplies a power supply voltage to the voltage sensor (46) and the interface circuit (48), prior to the drive circuit (40, 42). The control device (4) turns off the switch when the detection value of the voltage sensor (46) of at least one of the plurality of unit converters (5) is more than or equal to a predetermined value.

Abstract: A control device generates a voltage command value for controlling a current flowing between a three-phase AC power supply and a power converter such that a full voltage representative value representing voltage values of all power storage devices agrees with a DC voltage command value. The control device generates a zero-phase voltage command value for controlling a circulating current flowing in a delta connection such that the voltage values of the power storage devices are balanced among first to third arms. The control device combines the voltage command value and the zero-phase current command value to generate an output voltage command value for controlling an output voltage of each unit converter. The control device removes a control amount of the full voltage representative value from a computation of the zero-phase voltage command value to cause output current control and circulating current control not to interfere with each other.

Abstract: A power converter is electrically connected with an AC power supply via a switch, and is configured with a plurality of unit converters (5) connected in series. A drive circuit (40, 42) drives a plurality of switching elements (11 to 14) of a main circuit (30). An interface circuit (48) outputs a detection value of a voltage sensor (46) to a control device (4). If a bypass switch (7) is turned off when the power converter is activated, each of the plurality of unit converters (5) charges a capacitor (15) using power supplied from the AC power supply. When the power converter is activated, a power supply (50) supplies a power supply voltage to the voltage sensor (46) and the interface circuit (48), prior to the drive circuit (40, 42). The control device (4) turns off the switch when the detection value of the voltage sensor (46) of at least one of the plurality of unit converters (5) is more than or equal to a predetermined value.

Abstract: In a power conversion device, an inverter (10) of each of three arms (A1 to A3) is controlled such that circulating current (Iz) of three arms (A1 to A3) follows a reference (Izrt) in a test period (times t3 to t4) in which a power system (1) is cut off from the three arms (A1 to A3), and whether the power conversion device is normal is determined based on circulating current (Iz) in the test period. Whether the power conversion device is normal therefore can be determined without affecting the power system (1).