An image display device of the present invention comprises a display and a power supply unit, and the power supply unit comprises: a first voltage detection unit that detects an input AC voltage by using a first resistance element; a second voltage detection unit that detects an input AC voltage by using a differential circuit having a capacitor element and a second resistance element; a converter that converts the level of the input voltage on the basis of a switching operation of a switching element so as to output a DC voltage; and a control unit that may control the switching element in the converter to be turned on, on the basis of a first signal detected by the first voltage detection unit or a second signal detected by the second voltage detection unit. As such, the present invention operates stably even when an AC voltage of a square wave is applied.

An image display device of the present invention comprises a display and a power supply unit, and the power supply unit comprises: a first voltage detection unit that detects an input AC voltage by using a first resistance element; a second voltage detection unit that detects an input AC voltage by using a differential circuit having a capacitor element and a second resistance element; a converter that converts the level of the input voltage on the basis of a switching operation of a switching element so as to output a DC voltage; and a control unit that may control the switching element in the converter to be turned on, on the basis of a first signal detected by the first voltage detection unit or a second signal detected by the second voltage detection unit. As such, the present invention operates stably even when an AC voltage of a square wave is applied.

An electrical system can include an isolated bidirectional converter (having an input couplable to a grid connection and an output couplable to a battery) and an isolated converter (having an input coupled to the input of the isolated bidirectional converter and couplable to the grid connection, with an AC output coupled to a convenience outlet). The electrical system can further include a controller that controls operation of the converters to operate in one of a plurality of modes including a charging mode in which the isolated bidirectional converter operates in a forward direction to charge the battery and the non-isolated converter powers the convenience outlet from the grid connection, and a non-charging mode in which the isolated bidirectional converter operates in a reverse direction to power the non-isolated converter from the battery and the non-isolated converter powers the convenience outlet.

The present invention provides a power supply device and a power supply method for a DC electric arc furnace, wherein the power supply device comprises phase-shifting rectifier transformers, rectifying units and a regulator; through a structural design of a plurality of branches and a plurality of rectifying units at an output end of each phase-shifting rectifier transformer, and a structural design that outputs of the plurality of rectifying units are connected in parallel and then connected to a power supply short network of a DC electric arc furnace through bus bars, a current output topological structure is formed, which can provide a stable large current for one electrode assembly, and a plurality of current output topological structures can supply power to a plurality of electrode assemblies, so that requirement of a larger power supply current of the DC electric arc furnace can be satisfied; positions of top electrodes are judged and adjusted by the regulator according to real-time working parameters, which ensures that a lifting mechanism of the top electrodes can steadily perform the function of stabilizing arc burning for a long time; at the same time, output voltages and output currents of the rectifying units are adjusted by the regulator according to feedback of the real-time working parameters, so as to provide stable electric energy for the DC electric arc furnace.

Disclosed herein is a battery charger for electric vehicle includes a motor configured to generate power for driving the electric vehicle, an inverter configured to provide the power to the motor, an AC power input terminal configured to be input at least one AC power of single phase AC power and polyphaser AC power from a slow charger, a power factor corrector configured to include a plurality of full bridge circuits through which the AC power is input through the AC power input terminal, a link capacitor configured to connect in parallel with the power factor corrector, a switch network configured to include a first switch SW A provided to connect any one of a plurality of AC power input lines and a neutral line constituting the AC power input terminal with the power factor corrector, and a second switch provided to transfer one of a direct current power input from a quick charger and an alternating current power input from a slow charger to a high voltage battery and a controller configured to control the power factor corrector and the switch network according to the conditions of the AC power and the DC power.

System and methods for power conversion are provided. Aspects include a first switching module comprising a first set of switches, wherein the first set of switches comprise wide-bandgap devices having a first bandgap, a second switching module comprising a second set of switches, wherein the second set of switches comprise semiconductor devices having a second bandgap, and wherein the first bandgap is larger than the second bandgap, an alternating current (AC) power source connected to the first switching module and the second switching module, a first capacitor bank, a second capacitor bank, and a controller configured to operate the first switching module and the second switching module to create a first direct current (DC) voltage across the first capacitor bank and a second direct current (DC) voltage across the second capacitor bank.

System and methods for power conversion are provided. Aspects include a first switching module comprising a first set of switches, wherein the first set of switches comprise wide-bandgap devices having a first bandgap, a second switching module comprising a second set of switches, wherein the second set of switches comprise semiconductor devices having a second bandgap, and wherein the first bandgap is larger than the second bandgap, an alternating current (AC) power source connected to the first switching module and the second switching module, a first capacitor bank, a second capacitor bank, and a controller configured to operate the first switching module and the second switching module to create a first direct current (DC) voltage across the first capacitor bank and a second direct current (DC) voltage across the second capacitor bank.

A voltage balance control method for a flying-capacitor multilevel converter is provided. If the amplitude of the resultant current of the inductor currents from a plurality of output inductors is lower than or equal to a threshold current value, the flowing direction of the inductor current of at least one flying-capacitor multilevel branch circuit is controlled to be changed. Consequently, the problem of erroneously judging the current direction is avoided. Moreover, when the inductor current is low, the voltage of the flying capacitor is correspondingly controlled. Consequently, the voltage balance of the flying capacitor of the flying-capacitor multilevel converter can be achieved more easily.

This application provides a converter and an on-board charger, to avoid a short-circuit fault of the converter while inhibiting a surge impact. The converter includes: a power factor correction PFC circuit, a surge protection circuit, and a switch circuit. The PFC circuit is configured to: convert a first component of a first alternating current received by an alternating current terminal of the PFC circuit into a first direct current, and output the first direct current through a direct current terminal of the PFC circuit; and convert a second direct current received by the direct current terminal of the PFC circuit into a second alternating current, and output the second alternating current through the alternating current terminal of the PFC circuit.

At least one example embodiment is directed to a method for controlling a rectifier. The method includes applying a first control signal to a first switch of the rectifier to cause a first current to flow through a first inductor of the rectifier, applying a second control signal to a second switch of the rectifier to cause a second current to flow through a second inductor. The second control signal and the first control signal have a phase difference. The method includes detecting that the first current falls to a first minimum value at a first time, detecting that the second current falls to a second minimum value at a second time, determining a first difference between the first time and the second time, and determining whether to adjust the second control signal based on the first difference to bring the phase difference closer to a target phase difference.