A switching power supply that has a reduced conduction loss, when a direct current power supply is connected as an input power supply, by changing a part of a circuit for alternating current-to-direct current conversion, is provided. The switching power supply includes power input terminals to which the direct current power supply or an alternating current power supply is connected; power output terminals configured to output electric power; a smoothing capacitor connected between the power output terminals; a first non-insulated chopper circuit connected between the power output terminals; a second non-insulated chopper circuit connected between the power output terminals; and a switching circuit configured to switch a connection circuit provided between the first non-insulated chopper circuit and the second non-insulated chopper circuit, and the power input terminals.

A chopper section of a power supply device includes a plurality of step-down chopper circuits, and multiphase control of the step-down chopper circuits is performed using gate signals having phases displaced from each other. This shortens the period with which output signals of the step-down chopper circuits are changed. Shortening the period reduces the amount of jitter resulting from a gap between the occurrence of a command signal and a sampling point that is a point in time at which a gate signal is generated. The number of phases of the gate signals equals the number of phases of the step-down chopper circuits. The control of the gate signal generator is asynchronous to feedback control by the controller. Points in time (sampling points) at which gate signals are generated are points in time of generation (sampling points) after a point in time at which the controller calculates a manipulated value.

A chopper section of a power supply device includes a plurality of step-down chopper circuits, and multiphase control of the step-down chopper circuits is performed using gate signals having phases displaced from each other. This shortens the period with which output signals of the step-down chopper circuits are changed. Shortening the period reduces the amount of jitter resulting from a gap between the occurrence of a command signal and a sampling point that is a point in time at which a gate signal is generated. The number of phases of the gate signals equals the number of phases of the step-down chopper circuits. The control of the gate signal generator is asynchronous to feedback control by the controller. Points in time (sampling points) at which gate signals are generated are points in time of generation (sampling points) after a point in time at which the controller calculates a manipulated value.

An uninterruptible power supply device includes a bidirectional chopper that converts a first DC voltage supplied from a battery into a second DC voltage and supplies the second DC voltage to an inverter when a power failure of a commercial AC power supply occurs. The bidirectional chopper includes a capacitor that stabilizes the second DC voltage. The uninterruptible power supply device further includes: a current detector that detects an output current of the battery; and a control circuit that, based on a detection result by the current detector, calculates an estimated temperature increase value of the capacitor every time a predetermined time period elapses, and stops an operation of the bidirectional chopper when the calculated estimated temperature increase value is higher than an upper limit value.

An uninterruptible power supply device includes a bidirectional chopper that converts a first DC voltage supplied from a battery into a second DC voltage and supplies the second DC voltage to an inverter when a power failure of a commercial AC power supply occurs. The bidirectional chopper includes a capacitor that stabilizes the second DC voltage. The uninterruptible power supply device further includes: a current detector that detects an output current of the battery; and a control circuit that, based on a detection result by the current detector, calculates an estimated temperature increase value of the capacitor every time a predetermined time period elapses, and stops an operation of the bidirectional chopper when the calculated estimated temperature increase value is higher than an upper limit value.

A chopper section of a power supply device includes a plurality of step-down chopper circuits, and multiphase control of the step-down chopper circuits is performed using gate signals having phases displaced from each other. This shortens the period with which output signals of the step-down chopper circuits are changed. Shortening the period reduces the amount of jitter resulting from a gap between the occurrence of a command signal and a sampling point that is a point in time at which a gate signal is generated. The number of phases of the gate signals equals the number of phases of the step-down chopper circuits. The control of the gate signal generator is asynchronous to feedback control by the controller. Points in time (sampling points) at which gate signals are generated are points in time of generation (sampling points) after a point in time at which the controller calculates a manipulated value.

A chopper section of a power supply device includes a plurality of step-down chopper circuits, and multiphase control of the step-down chopper circuits is performed using gate signals having phases displaced from each other. This shortens the period with which output signals of the step-down chopper circuits are changed. Shortening the period reduces the amount of jitter resulting from a gap between the occurrence of a command signal and a sampling point that is a point in time at which a gate signal is generated. The number of phases of the gate signals equals the number of phases of the step-down chopper circuits. The control of the gate signal generator is asynchronous to feedback control by the controller. Points in time (sampling points) at which gate signals are generated are points in time of generation (sampling points) after a point in time at which the controller calculates a manipulated value.

A switching power supply that has a reduced conduction loss, when a direct current power supply is connected as an input power supply, by changing a part of a circuit for alternating current-to-direct current conversion, is provided. The switching power supply includes power input terminals to which the direct current power supply or an alternating current power supply is connected; power output terminals configured to output electric power; a smoothing capacitor connected between the power output terminals; a first non-insulated chopper circuit connected between the power output terminals; a second non-insulated chopper circuit connected between the power output terminals; and a switching circuit configured to switch a connection circuit provided between the first non-insulated chopper circuit and the second non-insulated chopper circuit, and the power input terminals.

A switching power supply that has a reduced conduction loss, when a direct current power supply is connected as an input power supply, by changing a part of a circuit for alternating current-to-direct current conversion, is provided. The switching power supply includes power input terminals to which the direct current power supply or an alternating current power supply is connected; power output terminals configured to output electric power; a smoothing capacitor connected between the power output terminals; a first non-insulated chopper circuit connected between the power output terminals; a second non-insulated chopper circuit connected between the power output terminals; and a switching circuit configured to switch a connection circuit provided between the first non-insulated chopper circuit and the second non-insulated chopper circuit, and the power input terminals.

Provided are a method for controlling operation of a module level power electronics (MLPE) device, a method for controlling MLPE devices and a photovoltaic system. In the method for controlling operation of a MLPE device, if it is determined that a current of a photovoltaic string where the MLPE device is located is less than a current threshold and coding information sent by a converter in the photovoltaic system is not received for a first preset time period, an output voltage or an output power of the MLPE device is controlled to be less than a corresponding threshold.