A low-voltage circuit in a bidirectional DC-DC converter converts output AC power from a high-voltage circuit to DC power to charge a smoothing reactor and discharge the smoothing reactor, and includes an active snubber circuit including switching elements and each having a backward diode and a snubber capacitor. The snubber capacitor of the active snubber circuit has its one end connected to a drain end of the switching elements and has its other end connected to a node between a center tap of a high-frequency transformer and a smoothing reactor.

A low-voltage circuit in a bidirectional DC-DC converter converts output AC power from a high-voltage circuit to DC power to charge a smoothing reactor and discharge the smoothing reactor, and includes an active snubber circuit including switching elements and each having a backward diode and a snubber capacitor. The snubber capacitor of the active snubber circuit has its one end connected to a drain end of the switching elements and has its other end connected to a node between a center tap of a high-frequency transformer and a smoothing reactor.

A method for controlling a power conversion system includes: configuring a carrier period of the power modules, and configuring a phase shift of carrier waves of the adjacent power modules to be 2π/N; selecting M power modules to operate within the carrier period, where O≤M≤N, and providing a modulation wave to the power modules, an amplitude of the modulation wave being A/N of a carrier peak of the carrier waves; and comparing the value of the modulation wave with a value of the carrier wave of each of the power modules, respectively, wherein, when the value of the modulation wave is greater than the value of the carrier wave, the corresponding power module runs; when the value of the modulation wave is less than or equal to the value of the carrier wave, the corresponding power module stops.

A method for controlling a power conversion system includes: configuring a carrier period of the power modules, and configuring a phase shift of carrier waves of the adjacent power modules to be 2π/N; selecting M power modules to operate within the carrier period, where O≤M≤N, and providing a modulation wave to the power modules, an amplitude of the modulation wave being A/N of a carrier peak of the carrier waves; and comparing the value of the modulation wave with a value of the carrier wave of each of the power modules, respectively, wherein, when the value of the modulation wave is greater than the value of the carrier wave, the corresponding power module runs; when the value of the modulation wave is less than or equal to the value of the carrier wave, the corresponding power module stops.

A switched mode power supply (SMPS) includes a filter (202), a power factor correction (PFC) circuit (204), and a control circuit (206, 406) configured to determine various electrical parameters of the SMPS. In some embodiments, the control circuit (206, 406) is configured to determine a power line frequency and an AC input voltage based on an AC line voltage and an AC neural voltage. In other embodiments, the control circuit (206, 406) is configured to determine an AC input current based on a reactive current flowing through the filter (202) and a PFC AC current. In further embodiments, the control circuit (206, 406) is configured to report a value of an electrical parameter if value is determined to be accurate. Other example switch mode power supplies, control circuits and methods are also disclosed.

In a power conversion system, a power converter includes a power conversion circuit connected to a direct current (DC) source via a DC distribution line and converts and supplies received DC power to a load, and a power conversion control unit. A power stabilizing device is disposed between the DC distribution line and the power converter and stabilizes a DC voltage applied from the DC power source. A control power source of the power stabilizing device performs current control of the current transformer to suppress DC magnetization caused by a DC current component of the primary current while compensating for a varying component of the DC voltage. The control power source acquires current information or voltage information calculated from control information used by the power conversion control unit for control operations related to energization of the load and uses it as control information for the power stabilizing device.

In a power conversion system, a power converter includes a power conversion circuit connected to a direct current (DC) source via a DC distribution line and converts and supplies received DC power to a load, and a power conversion control unit. A power stabilizing device is disposed between the DC distribution line and the power converter and stabilizes a DC voltage applied from the DC power source. A control power source of the power stabilizing device performs current control of the current transformer to suppress DC magnetization caused by a DC current component of the primary current while compensating for a varying component of the DC voltage. The control power source acquires current information or voltage information calculated from control information used by the power conversion control unit for control operations related to energization of the load and uses it as control information for the power stabilizing device.

A power system includes a DC/AC converter, a traction battery, an AC/DC converter electrically connected between the DC/AC converter and traction battery, and a transformer electrically connected between the DC/AC converter and AC/DC converter. The AC/DC converter includes a plurality of semiconductor devices and a plurality of capacitors such that during power transfer from the DC/AC converter to the traction battery, a voltage across each of the capacitors is half of a battery voltage.

A power system includes a DC/AC converter, a traction battery, an AC/DC converter electrically connected between the DC/AC converter and traction battery, and a transformer electrically connected between the DC/AC converter and AC/DC converter. The AC/DC converter includes a plurality of semiconductor devices and a plurality of capacitors such that during power transfer from the DC/AC converter to the traction battery, a voltage across each of the capacitors is half of a battery voltage.

A three-phase AC reactor according to an embodiment of the present invention includes three-phase coils that are not arranged in parallel, an input and output terminal block having an input and output unit having a parallel arrangement, and an external connection position change unit disposed between a coil end of each of the three-phase coils and the input and output terminal block to connect the coil end to the input and output terminal block.