A battery charging circuit can include: a primary rectifier circuit configured to rectify an input AC voltage into a rectified voltage signal; a DC-DC converter configured to generate a charging current according to the rectified voltage signal, in order to charge a battery; a control circuit configured to adjust the charging current by controlling an operation state of the DC-DC converter according to a charging requirement, in order to make an average value of the charging current meet the charging requirement; and where the charging current is controlled to be zero when an absolute value of the input AC voltage is lower than a predetermined threshold.

A battery charging circuit can include: a primary rectifier circuit configured to rectify an input AC voltage into a rectified voltage signal; a DC-DC converter configured to generate a charging current according to the rectified voltage signal, in order to charge a battery; a control circuit configured to adjust the charging current by controlling an operation state of the DC-DC converter according to a charging requirement, in order to make an average value of the charging current meet the charging requirement; and where the charging current is controlled to be zero when an absolute value of the input AC voltage is lower than a predetermined threshold.

A power supply system with line loss reduction supplies power to a load through a power line. The power supply system includes a step-up converter, a detection circuit, and a control unit. The control unit sets a terminal voltage required by the load, controls an output voltage of the step-up converter to be terminal voltage, and acquires an output current corresponding to the terminal voltage to be a present current by the detection circuit. The control unit controls the output voltage to be a modulated voltage, and acquires an output current corresponding to the modulated voltage to be a modulated current by the detection circuit. The control unit adjusts the output voltage to be a first predetermined voltage according to the terminal voltage, the present current, the modulated voltage, and the modulated current.

A power supply system with line loss reduction supplies power to a load through a power line. The power supply system includes a step-up converter, a detection circuit, and a control unit. The control unit sets a terminal voltage required by the load, controls an output voltage of the step-up converter to be terminal voltage, and acquires an output current corresponding to the terminal voltage to be a present current by the detection circuit. The control unit controls the output voltage to be a modulated voltage, and acquires an output current corresponding to the modulated voltage to be a modulated current by the detection circuit. The control unit adjusts the output voltage to be a first predetermined voltage according to the terminal voltage, the present current, the modulated voltage, and the modulated current.

In the parallel operation of power supply units, a high line ripple current may be observed in output when the power supply units (PSUs) are supplied with different inputs. For example, a high line ripple current may be observed when PSUs were supplied with different line frequency inputs and/or when PSUs were supplied with different phase angle input lines. A low pass filter is in a control loop which is capable of filtering the line frequency to get an average current reference signal. The average current reference signal is compared with the real time output current to generate an error signal. This error signal is fed back to a voltage control loop to adjust the output in order to compensate the line ripple.

In the parallel operation of power supply units, a high line ripple current may be observed in output when the power supply units (PSUs) are supplied with different inputs. For example, a high line ripple current may be observed when PSUs were supplied with different line frequency inputs and/or when PSUs were supplied with different phase angle input lines. A low pass filter is in a control loop which is capable of filtering the line frequency to get an average current reference signal. The average current reference signal is compared with the real time output current to generate an error signal. This error signal is fed back to a voltage control loop to adjust the output in order to compensate the line ripple.

The present disclosure is directed to switch a voltage to be supplied to a power source switch in accordance with a state of a power source of an apparatus and restrain power consumption of the power source switch.

A power generation device includes a first generator connected to a prime mover, a second generator connected to the prime mover, a first DCDC converter connected to the first generator, and a second DCDC converter connected to the second generator.

A printer system includes a first apparatus including a first voltage source for converting an inputted AC voltage to a first DC voltage and for outputting the converted first DC voltage, and a first controller operable by a voltage based on the first DC voltage outputted from the first voltage source; and a second apparatus including a second voltage source for converting an inputted AC voltage to a second DC voltage and for outputting the converted second DC voltage, and a second controller operable by a voltage based on the first DC voltage outputted from the first voltage source. The second apparatus includes a first switching portion for switching a state thereof between a connection state in which the AC voltage is supplied to the second voltage source and a non-connection state in which supply of the AC voltage is cut off.

A fault handling system of a solid-state transformer, including a first power unit and a second power unit that are cascaded and connected is provided. The first power unit includes a first auxiliary supply, a first control module, and a first communication module. The first auxiliary supply and the first control module are both electrically connected to two ends of a first busbar capacitor. The first control module is configured to detect a voltage of the first busbar capacitor. The second power unit includes a second auxiliary supply and a second control module. The second auxiliary supply and the second control module are both electrically connected to two ends of a second busbar capacitor. The first communication module outputs fault information to the second control module when the first control module detects that the voltage of the first busbar capacitor is greater than a threshold.