A power supply system for arc furnace is described. The power supply system includes a power converter and a polyphase transformer. The power supply system further includes first disconnecting means connecting the input of the power converter to the primary circuit, second disconnecting means connecting the output of the power converter to the primary circuit, and the power supply system further includes a control circuit configured to control the power converter to supply the electrode and to stabilize the courant and the voltage delivered by the grid to reduce reactions in the grid when the first disconnecting means are open and the second disconnecting means are closed, and to control the power converter to stabilize the courant and the voltage delivered by the grid to reduce reactions in the grid when the first disconnecting means are closed and the second disconnecting means are open.

The present disclosure relates to electric converters and methods of controlling the same. One dual-active-bridge direct current to direct current (DC-DC) converter includes a transformer having a primary winding and a secondary winding, a first H-bridge connected to the primary winding, a second H-bridge connected to the secondary winding, and a current sensor structured to measure a current of the transformer. The first H-bridge includes a plurality of switch devices. The second H-bridge includes a plurality of switch devices. The dual-active-bridge DC-DC converter further includes a controller configured to control an on/off state for each of the plurality of switch devices of the first H-bridge and the plurality of switch devices of the second H-bridge based at least in part on the current of the transformer measured by the current sensor.

The present disclosure relates to electric converters and methods of controlling the same. One dual-active-bridge direct current to direct current (DC-DC) converter includes a transformer having a primary winding and a secondary winding, a first H-bridge connected to the primary winding, a second H-bridge connected to the secondary winding, and a current sensor structured to measure a current of the transformer. The first H-bridge includes a plurality of switch devices. The second H-bridge includes a plurality of switch devices. The dual-active-bridge DC-DC converter further includes a controller configured to control an on/off state for each of the plurality of switch devices of the first H-bridge and the plurality of switch devices of the second H-bridge based at least in part on the current of the transformer measured by the current sensor.

A passive boost network configured to boost and output an AC power signal having a predetermined frequency, can include: an input port; an output port configured to provide the AC power signal; first and second passive components coupled in series between first and second terminals of the input port; a third passive component coupled in series with the second passive component between first and second terminals of the output port; and where the first passive component is one of a capacitor and an inductor, and the second and third passive components are each the other of the capacitor and the inductor.

According to one embodiment, an inverter including a detector which detects a value of an output voltage and a value of an output current; a command value input unit which is capable of receiving a current command value; a current command value compensating unit which, when the value of the output voltage detected by the detector is equal to or lower than a predetermined value, computes a compensation current value for compensating the current command value; an adder which adds the compensation current value to the current command value and outputs the compensated current command value; and a current controller which computes a voltage command value so that a difference between the compensated current command value and the output current detected by the detector becomes zero.

A power supply includes a transistor that is connected to a primary winding of a transformer. A controller controls a switching operation of the transistor by quasi-resonant switching. The controller receives a feedback voltage and adjusts the feedback voltage to adjust a blanking frequency, which is an inverse of a blanking time during which the transistor is prevented from being turned on. The controller turns on the transistor after expiration of the blanking time based on a level of a resonant ring.

A first switch and a second switch connected in series to both terminals of a DC power source. A signal generation circuit generates a feedback signal based on the DC voltage detected by the voltage detection circuit, and outputs the feedback signal, the feedback signal for turning the first and second switches on and off. A burst oscillation circuit that generates a burst oscillation signal based on a feedback signal and turns the first switch element and the second switch element on and off based on the burst oscillation signal when the standby state is detected. The burst oscillation circuit comprises a capacitor and a rapid charge circuit. When this device returns from standby state to normal state, the rapid charging circuit charges the capacitor after the feedback signal exceeds the cancellation threshold voltage.

A burst oscillation circuit operates switches in a burst oscillation mode based on a feedback signal. A first burst operation cancellation threshold voltage comparator compares a first burst operation cancellation threshold voltage set higher than a voltage of the feedback signal that a load current reaches the standby threshold and a voltage of the feedback signal, and outputs a first output signal. A second burst operation cancellation threshold voltage comparator compares a second burst operation cancellation threshold voltage set lower than the voltage of the feedback signal that the load current reaches the standby threshold and higher than a voltage of the feedback signal during a non-oscillation period of the burst oscillation operation and the voltage of the feedback signal and outputs a second output signal. A standby cancellation circuit generates a standby cancel signal to cancel the standby state based on the first and second output signal.

A burst oscillation circuit operates switches in a burst oscillation mode based on a feedback signal. A first burst operation cancellation threshold voltage comparator compares a first burst operation cancellation threshold voltage set higher than a voltage of the feedback signal that a load current reaches the standby threshold and a voltage of the feedback signal, and outputs a first output signal. A second burst operation cancellation threshold voltage comparator compares a second burst operation cancellation threshold voltage set lower than the voltage of the feedback signal that the load current reaches the standby threshold and higher than a voltage of the feedback signal during a non-oscillation period of the burst oscillation operation and the voltage of the feedback signal and outputs a second output signal. A standby cancellation circuit generates a standby cancel signal to cancel the standby state based on the first and second output signal.

A burst oscillation circuit operates switches in a burst oscillation mode based on a feedback signal. A first burst operation cancellation threshold voltage comparator compares a first burst operation cancellation threshold voltage set higher than a voltage of the feedback signal that a load current reaches the standby threshold and a voltage of the feedback signal, and outputs a first output signal. A second burst operation cancellation threshold voltage comparator compares a second burst operation cancellation threshold voltage set lower than the voltage of the feedback signal that the load current reaches the standby threshold and higher than a voltage of the feedback signal during a non-oscillation period of the burst oscillation operation and the voltage of the feedback signal and outputs a second output signal. A standby cancellation circuit generates a standby cancel signal to cancel the standby state based on the first and second output signal.